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Graham, Catherine. "Habitat Selection and Activity Budgets of Keel-Billed Toucans at the Landscape Level." Condor 103, no. 4 (November 1, 2001): 776–84. http://dx.doi.org/10.1093/condor/103.4.776.
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Abstract Landscape-level behavioral information is needed to understand factors that underlie animal distributions in disturbed habitats. I examined habitat use and activity budgets of Keel-billed Toucans (Ramphastos sulfuratus) in a pasture-dominated landscape in Los Tuxtlas, Mexico. The objectives were to compare habitat selection at two scales, and to describe activity budgets of toucans with an emphasis on how behavior varied by habitat type. Six toucans were followed between January and July 1998 for a total of 349 hr. I noted behavior, bird location, and habitat type. At one spatial scale, birds' individual movement area was a nonrandom portion of the overall study area. When time spent in habitats by individual toucans was compared to habitat available in individual movement areas, habitat selection was also nonrandom. Forest remnants were preferred at both scales. Toucans spent approximately equal time foraging and perching (35–40%). Calling, preening, and social interactions each occupied 10% or less of the birds' activity budgets. All activities occurred in similar proportions in all habitat types, suggesting that different habitats provide many of the same resources. Combining individual patterns of habitat selection with activity budgets yields a better understanding of factors that allow populations to persist in disturbed landscapes. Selección de Hábitat y Asignación de Actividades del Tucán Ramphastos sulfuratus a Escala de Paisaje Resumen. Se requieren estudios de comportamiento enfocados a la escala de paisaje para comprender los factores que afectan la distribución de los organismos en hábitats perturbados. Se examinó el uso de hábitat y asignación de actividades del tucán Ramphastos sulfuratus en paisajes dominados por pastizales en Los Tuxtlas, México. Los objetivos fueron comparar la selección de hábitat a dos escalas espaciales y describir la asignación de actividades de los tucanes poniendo énfasis en cómo el comportamiento es afectado por el tipo de hábitat. Seis tucanes fueron seguidos entre enero y julio de 1998 por un total de 349 hr. Registré el comportamiento, la posición del ave, y el tipo de hábitat. A una de las escalas espaciales consideradas, el area individual de movimiento de las aves representó una porción no azarosa del area total de estudio. Cuando el tiempo consumido por individuo en un hábitat determinado fue comparado con el hábitat disponible en las áreas individuales de movimiento, la selección de hábitat difirió de una selección al azar. Los remanentes de selva fueron preferidos a ambas escalas. Los tucanes consumieron aproximadamente el mismo tiempo forrajeando y posados (35–40%). Los llamadas, así como las interacciones sociales ocuparon 10% o menos de la asignación de actividades de las aves. Todas las actividades se llevaron a cabo en proporciones similares en todos los tipos de hábitat. La combinación de patrones individuales de selección de hábitat con la asignación de actividades proporciona una mejor comprensión de los factores que permiten la subsistencia de poblaciones en hábitats perturbados.
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Lloyd, John D., and Thomas E. Martin. "Reproductive Success of Chestnut-Collared Longspurs in Native and Exotic Grassland." Condor 107, no. 2 (May 1, 2005): 363–74. http://dx.doi.org/10.1093/condor/107.2.363.
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AbstractHabitat loss and fragmentation have been identified as important factors in the decline of grassland bird populations. However, population declines are apparent even in prairie ecosystems that remain relatively intact suggesting that additional factors are involved. The degradation of breeding habitat may be one such factor, but few studies have examined habitat-specific demography of grassland birds, and thus little is known of how changes in breeding habitat may be related to population declines. We addressed this question by comparing reproductive success of Chestnut-collared Longspurs (Calcarius ornatus) in patches of native prairie and in monocultures of crested wheatgrass (Agropyron cristatum), a grass introduced from Asia. Using recently developed methods for estimating nest survival rate, we found that, independent of habitat type, daily nest survival generally declined from egg laying to fledging. We also found a positive effect of clutch size on nest survival rate, which we interpreted as evidence for individual heterogeneity in nest survival. Finally, we found that the odds of a nest surviving a given day were 17% lower in the exotic habitat, and that nestlings grew more slowly, and had a smaller final mass in the exotic habitat. Despite having lower reproductive success in the exotic habitat, we found no evidence that Chestnut-collared Longspurs preferred to nest in the native habitat. Our results show that the introduction and spread of a commonly planted exotic grass has adverse fitness consequences for a grassland bird, and highlight the importance of maintaining native prairie.Éxito Reproductivo de Calcarius ornatus en Praderas Nativas y ExóticasResumen. La pérdida y fragmentación de hábitat han sido identificados como factores importantes con respecto a la disminución de las poblaciones de aves de pastizales. Sin embargo, las poblaciones están en disminución aún en ecosistemas de pradera relativamente intactos, lo que sugiere que otros factores están involucrados en el proceso. La degradación del hábitat de nidificación podría ser uno de estos factores adicionales, pero pocos estudios han examinado la demografía de aves de pastizales en distintos hábitats. En consecuencia, se conoce muy poco acerca de cómo los cambios en el hábitat podrían estar relacionados con las disminuciones poblacionales. En este estudio abordamos esta pregunta comparando el éxito reproductivo de individuos de la especie Calcarius ornatus en parches de praderas nativas y en monocultivos de Agropyron cristatum, un pasto introducido de Asia. Empleando métodos recientemente desarrollados para estimar la tasa de supervivencia de los nidos, encontramos que independientemente del tipo de hábitat, la supervivencia diaria de los nidos en general disminuyó desde la puesta hasta el momento de emplumamiento de los pichones. También encontramos un efecto positivo del tamaño de la nidada sobre la tasa de supervivencia de los nidos, el cual interpretamos como evidencia de que existe heterogeneidad individual en la supervivencia de los nidos. Finalmente, encontramos que en el ambiente exótico la probabilidad de sobrevivir de un nido durante un día dado fue un 17% menor, los pichones crecieron más lentamente y presentaron una masa final menor. A pesar de presentar un éxito reproductivo menor en el ambiente exótico, no encontramos evidencia de que las aves prefirieran nidificar en el ambiente nativo. Nuestros resultados muestran que la introducción y propagación de un pasto exótico que es plantado con frecuencia tiene efectos adversos sobre la adecuación de un ave de pastizal, y resaltan la importancia de mantener las praderas nativas.
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Gonçalves, Teresa Cristina M., Dayse S. Rocha, and Rodolfo A. Cunha. "Hábito alimentar de Triatoma vitticeps no Estado do Rio de Janeiro, Brasil." Revista de Saúde Pública 34, no. 4 (August 2000): 348–52. http://dx.doi.org/10.1590/s0034-89102000000400006.
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OBJETIVO: O estudo do hábito alimentar dos triatomíneos tem contribuído para o conhecimento da sua biologia no habitat natural. Triatoma vitticeps, espécie que vem invadindo freqüentemente o domicílio apresentando-se infectado por T. cruzi, foi analisado sob esse aspecto, possibilitando conhecer a situação epidemiológica da área. MÉTODOS: De fevereiro de 1989 a abril de 1993, 122 espécimes de T. vitticeps foram capturados em duas áreas da localidade de Triunfo, 2° Distrito do Município de Santa Maria Madalena (RJ). Os insetos foram dissecados para a retirada do conteúdo estomacal. Os anti-soros utilizados foram: homem, vaca, cavalo, cão, porco, tatu, gambá, roedor e ave. RESULTADOS: Do total analisado, 79 estavam positivos e 43 negativos para os anti-soros testados: tatu (30,3%) > homem e porco (13,1%) > ave e cão (11,5%) > cavalo (5,7%) > gambá (4,9%) > roedor (4,1%) > boi (3,3%). As fontes alimentares identificadas variaram de 1 a 4 e 6: 0 - 25,41%; 1 - 45,08%; 2 - 10,66%; 3 - 6,56%; 4 - 1,64% e 6 - 0,82%. Quanto à infecção por T. cruzi, 74 espécimes (65,54%) estavam positivos, 39 (34,51%) negativos e 9 não foram examinados. CONCLUSÕES: Os resultados caracterizam o hábito silvestre de T. vitticeps e a tripanosomíase como uma enzootia. A vigilância epidemiológica se faz necessária para o acompanhamento do comportamento dessa espécie.
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Costa e Silva, Leticia Da, Denise Fukumi Tsunoda, and Viviane Deslandes. "Mineração de dados: busca de conhecimento sobre a evolução do canto da família Thamnophilidae." AtoZ: novas práticas em informação e conhecimento 1, no. 1 (June 1, 2011): 61. http://dx.doi.org/10.5380/atoz.v1i1.41284.
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Introdução. Descreve a utilização de uma técnica de mineração de dados sobre o canto, a biologia e o micro-habitat da família Thamnophilidae (Aves) a fim de encontrar padrões que os relacionem. Método. Uma base de dados foi construída em planilha Excel® relacionando 82 espécies da família da ave Thamnophilidae com diversos atributos referentes às características do canto, da biologia e do micro-habitat em que são encontradas. Na análise utilizou-se o algoritmo Apriori no software WEKA 3.7.1. Resultados. Ao associar os diferentes atributos de 82 espécies diferentes considerando o suporte mínimo de 10% e a confiança mínima de 90% foram encontrados 172 padrões, dos quais 42 continham um dos atributos do canto: PC1 e PC2. Os padrões que relacionavam o atributo PC2 foram os mais significativos ao indicar a relação deste com o tamanho e gênero da família. Os resultados colaboraram para gerar a hipótese de que os atributos do canto possuem comportamentos não relacionados. Conclusões. O experimento demonstrou que o algoritmo pode ser melhor aproveitado em bases de dados maiores e/ou cuja padronização dos dados apresente menor número de categorias, o que pode ser uma limitação no campo da macroecologia. Mas, ao mesmo tempo, se mostrou um instrumento alternativo para o estudo exploratório de relações entre diversos atributos, cujos resultados podem servir de objetos de análises mais aprofundadas.
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Mateus, Wagner de Deus, and Maria Inês Gasparetto Higuchi. "Percepções na Conservação da Fauna Silvestre Amazônica em Risco de Extinção." Fronteiras: Journal of Social, Technological and Environmental Science 9, no. 1 (March 4, 2020): 358–79. http://dx.doi.org/10.21664/2238-8869.2020v9i1.p358-379.
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Esse trabalho apresenta as percepções da fauna silvestre de moradores das comunidades amazônicas participantes dos programas de conservação do gavião-real (Harpia harpyja) e tracajá (Podocnemis unifilis). A partir da observação sistemática e entrevistas semiestruturadas a pesquisa discute a constituição das percepções na conservação dessas espécies-bandeiras, a partir de processos sociohistóricos e saberes ambientais peculiares em cada comunidade. As percepções sobre o gavião-real se fundamentam na intangibilidade da ave, que os permite ora apreciar sua beleza, e ora temer suas poderosas garras. A conservação se embasa no reconhecimento de sua altivez silvestre e manutenção de seu habitat, mesmo que distante da vida comunitária, caracterizando um comportamento interespecífico. As percepções sobre o tracajá se constituem na sua docilidade, utilidade e função quase doméstica. A conservação se embasa no seu comportamento transespecífico, que o caracteriza como integrante “natural” da comunidade. Para essas pessoas, a percepção da conservação dessas espécies se constitui pela proximidade, conhecimento e experiências.
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Gibson, A. Jamie F., Heather D. Bowlby, and Peter G. Amiro. "Are wild populations ideally distributed? Variations in density-dependent habitat use by age class in juvenile Atlantic salmon (Salmo salar)." Canadian Journal of Fisheries and Aquatic Sciences 65, no. 8 (August 2008): 1667–80. http://dx.doi.org/10.1139/f08-087.
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We examined relationships between abundance and habitat use in three age classes of juvenile Atlantic salmon ( Salmo salar ) in the Stewiacke River, Nova Scotia, Canada. Using stream gradient as a proxy for habitat quality, we used a double half normal function, modified to include density dependence, to model the relationship between habitat quality and fish density. We found that density was asymmetrically distributed around a similar optimum gradient for all three age classes regardless of abundance. Habitat use was highly density-dependent for age-0 and age-1 juveniles, but not for age-2+ salmon. As abundance of age-0 and age-1 salmon increased, their relative density decreased in low-gradient habitat and increased in higher-gradient habitat, although their absolute density increased in all stream gradient categories. Variation in habitat use was consistent with ideal free theory for age-1 juveniles in high-gradient habitat, but not in low-gradient habitat. Age-2+ individuals appeared not to modify their distribution among habitats, even though increasing competition changes the relative benefit of low-gradient habitat in terms of resource acquisition. In contrast, age-1 individuals responded to increased competition by modifying their distribution along the habitat gradient, even though this may have slightly reduced an individual’s potential for growth.
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Mateus, Wagner De Deus, Mariana Baldoino, and Maria Inês Gasparetto Higuchi. "A dimensão participativa na conservação da fauna silvestre amazônica em risco de extinção." Acta Scientiarum. Human and Social Sciences 40, no. 3 (November 27, 2018): 42811. http://dx.doi.org/10.4025/actascihumansoc.v40i3.42811.
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O objetivo deste trabalho é descrever e analisar as percepções de moradores de comunidades amazônicas relativas às formas de inserção e participação nos programas de conservação do gavião-real (Harpia harpyja) e do tracajá (Podocnemis unifilis). A partir da observação sistemática e entrevistas semiestruturadas a pesquisa analisa os constructos que caracterizam a participação dos comunitários na conservação das espécies, de forma direta e indireta. As percepções mostram que a participação na conservação do tracajá se deu de forma direta, onde os comunitários estão inseridos na maioria das etapas do manejo dos quelônios, com prevalência nas atividades não técnicas, mas com atuação protagonista no programa de conservação. A conservação do gavião-real se deu de forma indireta. As pessoas que participavam do programa localizavam-se próximos do local e habitat da ave. Suas participações eram marcadas pela atuação como observadores dos processos técnicos, agentes coadjuvantes. Neste contexto, as externalidades afloraram e deram novos caminhos a forma de atuação na conservação, favorecendo o cenário biocultural. A forma de participação nos dois casos tem relação com as estratégias e estruturas do manejo utilizadas pelos programas, onde o co-manejo é o modelo a ser evidenciado.
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Schulz, Björn, and Sven Büchner. "Populations of Muscardinus avellanarius in north-western Europe can survive in forest poor landscapes, when there are enough hedges (Rodentia: Gliridae)." Lynx new series 49, no. 1 (2018): 57–68. http://dx.doi.org/10.2478/lynx-2018-0008.
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The hazel dormouse (Muscardinus avellanarius) is a strictly arboreal species. In its European lowland range, the forest coverage was heavily reduced during historical times, e.g. down to ca. 4% in the northern German federal state of Schleswig-Holstein in the 18th century. This low forest cover remained for 200 years. According to habitat models, hazel dormice cannot survive in the long-term in habitats with low levels of forest cover (<5–10%). To answer the question, how hazel dormouse populations survived in almost deforested areas the recent species distribution map for north-west Europe was analysed with a GIS-overlay of different habitat data. Additionally, historical maps for north-west Germany were analysed to find crucial historical landscape elements. The history of a site apparently influences the present status of hazel dormice. Forest cover of younger woodlands is still of importance but less determinant. Habitat tradition and continuity are important for habitat suitability for the hazel dormouse and identifying historical hedgerow systems and historical woodlands can help to find places with hitherto unknown presence of hazel dormouse. Apparently, for the hazel dormouse the lack of forest habitats in north-western Europe was successfully compensated by the creation of a hedgerow network. Hedgerows function as a habitat by themselves, not just as a connecting structure. A density of 50 m continuous high quality and well-connected hedgerows per hectare seems to be a minimum for the survival of hazel dormice in northwest European landscapes. The preservation of ancient habitats and the restoration of new habitats as core habitats and connections is a key strategy to facilitate the long-term survival and re-colonisation of species.
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Rosenfeld, Jordan S., and Todd Hatfield. "Information needs for assessing critical habitat of freshwater fish." Canadian Journal of Fisheries and Aquatic Sciences 63, no. 3 (March 1, 2006): 683–98. http://dx.doi.org/10.1139/f05-242.
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The core assumptions of critical habitat designation are a positive relationship between habitat and population size and that a minimum habitat area is required to meet a recovery target. Effects of habitat on population limitation scale from (i) effects on performance of individuals (growth, survival, fecundity) within a life history stage, to (ii) limitation of populations by habitats associated with specific life history stages, and (iii) larger-scale habitat structure required for metapopulation persistence. The minimum subset of habitats required to achieve a recovery target will depend on the extent, quality, and spatial configuration of habitats available to sequential life history stages. Although populations may be limited by available habitat for a single life history stage, altering habitat quality for subsequent stages will also affect individual survival and population size, providing multiple leverage points within a life history for habitat management to achieve recovery targets. When habitat-explicit demographic data are lacking, consequences of uncertainty in critical habitat assessment need to be explicit, and research should focus on identifying habitats most likely to be limiting based on species biology.
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Cockell, Charles S. "Types of habitat in the Universe." International Journal of Astrobiology 13, no. 2 (February 21, 2014): 158–64. http://dx.doi.org/10.1017/s1473550413000451.
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AbstractFrom a biological point of view, all environments in the Universe can be categorized into one of three types: uninhabitable, uninhabited habitat or inhabited habitat. This paper describes and defines different habitat types in the Universe with a special focus on environments not usually encountered on the Earth, but which might be common on other planetary bodies. They include uninhabited habitats, subtypes of which are sterile habitats and organic-free habitats. Examples of the different types of environments are provided with reference to the Eyjafjallajökull, Iceland. These habitat types are used to identify testable hypotheses on the abundance of different habitats and the distribution of life in the Universe.
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Virgl, John A., and François Messier. "Assessment of source-sink theory for predicting demographic rates among habitats that exhibit temporal changes in quality." Canadian Journal of Zoology 78, no. 8 (August 1, 2000): 1483–93. http://dx.doi.org/10.1139/z00-066.
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Within the framework of Pulliam's source-sink model we tested predictions of habitat-specific demography on a "closed" population of muskrats (Ondatra zibethicus L.) occupying three contiguous habitats that exhibited temporal changes in quality and quantity. We were able to distinguish between dispersal among habitats and mortality within each habitat, and induce temporal variation in operational-habitat availability and suitability by manipulating water level. Temporal variation in population size and density among habitats supported the source-sink model and was primarily associated with habitat-specific survival rates. For example, the mean annual over-winter mortality rate of individuals in the principal source habitat (0.87) was less than in the sink habitat (0.94), and subsequently the mean annual finite rate of increase (λ) was positive in the source habitat (λ = 1.41) and negative in the sink habitat (λ = 0.90). The high recruitment rate of juveniles in the prime habitat during autumn was also associated with significant emigration of juveniles from this habitat. Emigration of adults among habitats provided support for the role of spacing behaviour in regulating the breeding density of muskrats in prime habitat. However, in contrast to the assumption of source-sink theory, year-to-year variation in survival rate in the more marginal habitats appeared to be explained more by temporal changes in habitat suitability than by density. Significant emigration of juveniles from the sink habitat was not predicted and was largely dependent on current habitat conditions. In addition, the mean annual emigration rate was lowest in the principal source habitat (0.30) and highest in the more marginal habitats (0.62). Failure to detect directional emigration from prime to marginal habitats in the spring, as predicted by the source-sink model, was likely due to declining local population size. In environments where spatial differences in habitat quality are not static, and annual change in local population size is largely independent of density, current source-sink models must be modified to better predict individual dispersal strategies.
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Horsák, Michal, Michal Hájek, Daniel Spitale, Petra Hájková, Daniel Dítě, and Jeffrey C. Nekola. "The age of island-like habitats impacts habitat specialist species richness." Ecology 93, no. 5 (May 2012): 1106–14. http://dx.doi.org/10.1890/0012-9658-93.5.1106.
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Costa-Milanez, CB, G. Lourenço-Silva, PTA Castro, JD Majer, and SP Ribeiro. "Are ant assemblages of Brazilian veredas characterised by location or habitat type?" Brazilian Journal of Biology 74, no. 1 (February 2014): 89–99. http://dx.doi.org/10.1590/1519-6984.17612.
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Wetland areas in the Brazilian Cerrado, known as “veredas”, represent ecosystems formed on sandy soils with high concentrations of peat, and are responsible for the recharge of aquiferous reservoirs. They are currently under threat by various human activities, most notably the clearing of vegetation for Eucalyptus plantations. Despite their ecological importance and high conservation value, little is known about the actual effects of human disturbance on the animal community. To assess how habitat within different veredas, and plantations surrounding them affect ant assemblages, we selected four independent vereda locations, two being impacted by Eucalyptus monoculture (one younger and one mature plantation) and two controls, where the wetland was surrounded by cerrado vegetation. Ant sampling was conducted in May 2010 (dry season) using three complementary methods, namely baits, pitfall traps, and hand collection, in the wetland and in the surrounding habitats. A total of 7,575 ants were sampled, belonging to seven subfamilies, 32 genera and 124 species. Ant species richness and abundance did not differ between vereda locations, but did between the habitats. When impacted by the monoculture, ant species richness and abundance decreased in wetlands, but were less affected in the cerrado habitat. Ant species composition differed between the three habitats and between vereda locations. Eucalyptus plantations had an ant species composition defined by high dominance of Pheidole sp. and Solenopsis invicta, while natural habitats were defined by Camponotus and Crematogaster species. Atta sexdens was strictly confined to native habitats of non-impacted “veredas”. Eucalyptus monocultures require high quantities of water in the early stages, which may have caused a decrease in groundwater level in the wetland, allowing hypogeic ants such as Labidus praedator to colonise this habitat.
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Noguchi, Hideyuki, Akira Itoh, Takashi Mizuno, Kriangsak Sri-ngernyuang, Mamoru Kanzaki, Sakhan Teejuntuk, Witchaphart Sungpalee, et al. "Habitat divergence in sympatric Fagaceae tree species of a tropical montane forest in northern Thailand." Journal of Tropical Ecology 23, no. 5 (August 16, 2007): 549–58. http://dx.doi.org/10.1017/s0266467407004403.
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Spatial distributions of many tropical trees are skewed to specific habitats, i.e. habitat specialization. However, habitats of specialist species must be divergent, i.e. habitat divergence, to coexist in a local community. When a pair of species specialize in the same habitat, i.e. habitat convergence, they could not coexist by way of habitat specialization. Thus, analyses of habitat divergence, in addition to habitat specialization, are necessary to discuss coexistence mechanisms of sympatric species. In this study, the habitat specialization and habitat divergence along topographic gradients of eight sympatric tree species of the Fagaceae were studied in a 15-ha study plot in a tropical lower montane forest in northern Thailand. A statistical test with torus shift randomizations for 9673 trees of Fagaceae revealed significantly biased distributions for all of the species, for at least one of the four topographic variables used: elevation, slope inclination, aspect and convexity. Slope convexity was the most critical topographic variable, along which all but one species had significantly skewed distributions. Out of 112 possible combinations of species pairs and topographic variables, 18 (16%) and two pairs (1.8%) showed significant habitat divergence and habitat convergence, respectively. The observed habitat divergence alone could not completely explain the coexistence of the eight species. There was a gradation in the habitat position of each species, with relatively large overlaps between species distributed in similar habitats, and small overlaps between species associated with contrasting habitats, respectively. The gradual changes in the habitats of the species suggested that dividing the species into a small number of distinct habitat groups, such as ridge and valley specialists, would not be straightforward.
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Ollivier, Q. R., N. A. Bramwell, E. Hammill, C. Foster-Thorpe, and D. J. Booth. "Are the effects of adjacent habitat type on seagrass gastropod communities being masked by previous focus on habitat dyads?" Australian Journal of Zoology 63, no. 5 (2015): 357. http://dx.doi.org/10.1071/zo15057.
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Variation in abundance and diversity of organisms along habitat edges has long been a key research focus in both terrestrial and marine ecosystems. Previous investigations into edge effects in seagrass ecosystems have predominantly focussed on the seagrass–sandy substrate boundary. However, little is known about what role other habitats (e.g. rocky algal reefs) may play in faunal assemblage patterns. This study investigated the strength to which habitat type influenced gastropod assemblages within seagrass (Posidonia australis) beds, bordered by both sandy substrate and rocky algal reef. We found that benthic invertebrate community composition significantly changed with distance from rocky algal reef, but not with distance from sandy substrate. Proximity to rocky reef had a stronger effect on community composition than other local drivers examined (seagrass biomass and sand particle size). We hypothesise that gastropod affinity for rocky algal reef may be a result of both species-specific habitat preference, and lower predation pressure along adjacent rocky algal reef habitats. This study provides evidence that heterogeneous habitats within close proximity to seagrass beds may exert previously overlooked effects on the distribution of gastropod assemblages, highlighting the need for the inclusion of adjacent habitat type in experimental design for gastropod assemblage distribution studies.
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Rohmawati, Vivi Dwi, Husain Latuconsina, and Hasan Zayadi. "Fish Community in Different Mangrove Habitat in Banyuurip Ujung Pangkah – Gresik Regency." Agrikan: Jurnal Agribisnis Perikanan 14, no. 1 (April 6, 2021): 73–79. http://dx.doi.org/10.29239/j.agrikan.14.1.73-79.
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Mangroves are an important habitat for fish communities, as spawning, growing and foraging areas. This study aims to compare the species composition, presence frequency and structure of fish communities in different mangrove habitats. The research was conducted at Banyuurip Mangrove Center, Ujung Pangkah District, Gresik Regency, East Java, during July-August 2020. Determination of purposive sampling locations based on physical differences in mangrove habitats. Systematic sampling method was used to estimate the number of mangrove species using belt transects. Fish sample collection uses basic gill nets that are placed at high tide in each mangrove habitat. The results showed that the total number of individual mangrove vegetation was 505 from 12 species, the number of species and individual mangrove vegetation differed between habitats, and the highest was found in coastal mangrove habitats. The number of fish was found as many as 181 individuals from 11 species, 10 families and 5 orders. The number and composition of species, families and fish orders differ between mangrove habitats, with the highest number in coastal mangrove habitats. Mozambique tilapia (Oreochromis mossambicus) dominate the estuary mangrove habitat and giant trevally (Caranx sexfasciatus) dominate the coastal mangrove habitat. There are variations in the structure of fish communities between mangrove habitats, the dominance index value of the fish community in the estuary mangrove habitat is higher and in the medium category, while the coastal mangrove habitat is in the low category. On the other hand, the diversity index value of the fish community in the coastal mangrove habitat is in the high category and the estuary mangrove habitat is in the low category.
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Kiatoko, Nkoba, Suresh Kumar Raina, and Frank van Langevelde. "Impact of habitat degradation on species diversity and nest abundance of five African stingless bee species in a tropical rainforest of Kenya." International Journal of Tropical Insect Science 37, no. 03 (August 17, 2017): 189–97. http://dx.doi.org/10.1017/s174275841700011x.
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AbstractNatural habitat degradation often involves the reduction or disappearance of bee species. In Africa, stingless bees are hunted for honey, which is used as food, for medicinal purposes, and for traditional rituals. Severe habitat degradation due to human settlement is hypothesized to have a negative impact on the species diversity of the African stingless bee species. In this paper, we assess the impact of habitat degradation on the diversity of five stingless bee species across different habitats in the tropical rainforest of Kenya (indigenous forest, mixed indigenous forest) and its neighbouring landscape (grassland, village) in western Kenya. The species fauna, nest occurrence, and species diversity of the stingless bee species varied across the different habitats. The number of nesting habitats of the meliponine species varied between habitats in the tropical rainforest.Meliponula ferruginea(reddish brown) nested in five habitats, whileMeliponula bocandeiandMeliponula ferruginea(black) nested only in two habitat types. The species richness decreased within the different types of habitats and the indigenous and mixed indigenous forest contained more species than other habitats. The fauna composition in both homesteads was exclusively similar, while the indigenous and mixed indigenous forests were mostly similar. Similarity in habitat preferences for nesting was revealed betweenM. bocandeivsPlebeina hildebrandtiandM. ferruginea(reddish brown) vsHypotrigona gribodoi. The natural native indigenous forest had the most diverse community compared to the degraded habitats. There are taxon-specific responses to habitat change; and in our study, there is clear value in conserving the native indigenous forest.
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Ossola, Alessandro, Michael A. Nash, Fiona J. Christie, Amy K. Hahs, and Stephen J. Livesley. "Urban habitat complexity affects species richness but not environmental filtering of morphologically-diverse ants." PeerJ 3 (October 22, 2015): e1356. http://dx.doi.org/10.7717/peerj.1356.
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Habitat complexity is a major determinant of structure and diversity of ant assemblages. Following the size-grain hypothesis, smaller ant species are likely to be advantaged in more complex habitats compared to larger species. Habitat complexity can act as an environmental filter based on species size and morphological traits, therefore affecting the overall structure and diversity of ant assemblages. In natural and semi-natural ecosystems, habitat complexity is principally regulated by ecological successions or disturbance such as fire and grazing. Urban ecosystems provide an opportunity to test relationships between habitat, ant assemblage structure and ant traits using novel combinations of habitat complexity generated and sustained by human management. We sampled ant assemblages in low-complexity and high-complexity parks, and high-complexity woodland remnants, hypothesizing that (i) ant abundance and species richness would be higher in high-complexity urban habitats, (ii) ant assemblages would differ between low- and high-complexity habitats and (iii) ants living in high-complexity habitats would be smaller than those living in low-complexity habitats. Contrary to our hypothesis, ant species richness was higher in low-complexity habitats compared to high-complexity habitats. Overall, ant assemblages were significantly different among the habitat complexity types investigated, although ant size and morphology remained the same. Habitat complexity appears to affect the structure of ant assemblages in urban ecosystems as previously observed in natural and semi-natural ecosystems. However, the habitat complexity filter does not seem to be linked to ant morphological traits related to body size.
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Meynecke, J. O. "Coastal habitat connectivity ? implications for declared fish habitat networks in Queensland, Australia." Pacific Conservation Biology 15, no. 2 (2009): 96. http://dx.doi.org/10.1071/pc090096.
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Estuaries are widely recognized as key habitats supporting nearshore secondary production and catch of commercial fisheries. In Queensland, some of these coastal marine habitats are protected by the declared fish habitat programme run by the Department of Primary Industries and Fisheries. Expected environmental changes for Australian estuarine systems include reduced freshwater flow, increased sedimentation and with them, a loss of connectivity. At present, the relationship between the protected declared fish habitat and habitat connectivity remains unknown. By comparing long term coastal fish catch data with geomorphic characteristics of coastal habitats structural connectivity was previously identified as a potential driver of commercial fish catch in Queensland. An ecology landscape approach was used for this study to identify potential fish habitat hotspots along the coastline of Queensland thus allowing better defined networks of declared fish habitats. A comparison between this approach and the current declared fish habitats demonstrated potential deficits and provided important insights for fisheries management. Declared fish habitats should be placed in coastal habitats with high structural connectivity to ensure sustainability of fisheries in light of environmental changes.
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Grzybowski, Mirosław. "Principal Threats to the Conservation of Running Water Habitats in the Continental Biogeographical Region of Central Europe." Journal of Landscape Ecology 13, no. 2 (September 1, 2020): 32–61. http://dx.doi.org/10.2478/jlecol-2020-0009.
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AbstractThis paper discusses the threats to the running water habitats that are highly important to biodiversity the European Community in the Continental Biogeographical Region (CBR) of Europe, specifically in Poland. This study covers four water course habitat types distinguished in Natura 2000, which is a network of nature protection areas in the territory (3260, 3220, 3240, 3270 - the code of the habitat, as in Annex I of the Habitat Directive), occurring in 806 Special Areas of Conservation in Poland. Based on a multivariate analysis, we found significant differences in the conservation status of running water habitats resulting from a variety of threats, pressures, and activities. Agriculture has a number of negative impacts on running water habitats, which are most evident for the following habitats: 3260 > 3270. Forest management may have both negative (3260) and positive effects on habitats (3270). Natural system modifications strongly affect habitats 3240, 3270 > 3260. Among the negative anthropogenic influences are pollution (3260 > 3220); human intrusions, disturbances, and tourism (reported most often) (3260, 3270); transportation and service corridors (3260, and 3270); urbanization, residential, and commercial development tourism (3260); biological resource use other than for agriculture and forestry (3270 > 3260); and mining, extraction of materials, and energy production (3270). Geological events and natural catastrophes—most often inundation—were identified as important hazards for habitat 3240. The development of alien and invasive species strongly affects habitats 3240 > 3260, 3270, and natural biotic and abiotic processes affect habitats 3220 > 3260. Negative impacts associated with climate change were detected mostly for habitat 3260. Taking into account the threats identified, a list of recommended practices for running water habitat types is presented, to be considered in habitat conservation programmes.
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Palo, Anneli, and Mark Gimbutas. "Dynamics of tree layer composition, tree age and large diameter trees in Habitats Directive Annex I forest habitats in Estonia on the basis of monitoring data collected from 2010–2012." Forestry Studies 58, no. 1 (June 1, 2013): 57–73. http://dx.doi.org/10.2478/fsmu-2013-0006.
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Abstract The protection of late-succession forest habitats and continuous woodlands is the primary goal in Estonian forest nature conservation. Therefore ecological qualities of almost all forest stands in Estonian protected areas are described. Forest patches will be mapped and protected as Annex I forest habitats if they have enough structural and functional qualities. The member states of the European Union report in every six years about the conservation status of European Habitats Directive Annex I habitats. Changes in area as well as changes in habitat type’s structure and functions are also declared. In the present paper the dynamics in tree species composition, stand age and larger diameter trees of monitored Annex I forest habitats is analyzed. The mean age of stands is older than the Estonian mean value, but it is only slightly higher than the cutting age of the corresponding tree species. The mean diameter of larger living trees is in general larger than dead wood, which is indicative of the forest succession and historical low-intensive forest management. Currently, conservation activities support natural succession in forests that formerly were managed economically. Therefore, changes in the composition of tree layer species are to be expected. The dominance of spruce and the abundance of broad-leaved trees are increasing in non-managed forest habitats. In contrast, the proportion of pine, birch and aspen decreases significantly. In general the number of tree species in habitat patches will increase; thereby the dominance of certain species will decline. According to the Estonian interpretation of the forest types in the Manual of the Habitats Directive, some stands with changed main tree species will need to be reclassified. Therefore the area of some forest habitat types may increase in the future. On contrary the area and functional quality of some other habitat types may decrease.
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Rango, Jessamy J. "A Survey of Ant Species in Three Habitats at Mount St. Helens National Volcanic Monument." Psyche: A Journal of Entomology 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/415183.
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Ants were surveyed in three habitats at Mount St. Helens in 2008. The area most impacted by the 1980 eruption is the Pumice Plain. Less impacted is the Blowdown Zone where trees were toppled due to the blast. Two habitats were surveyed in the Pumice Plain varying in vegetation density (Pumice Plain Low-Vegetation (PPLV) and Pumice Plain High-Vegetation (PPHV)), and one habitat was surveyed in the Blowdown Zone (BDZ). Ten ant species were collected with the most species collected from the BDZ habitat and the least from the PPLV habitat. Ant abundance was higher at the BDZ and PPHV habitats than at the PPLV habitat. Ant biodiversity was highest at the BDZ habitat than at the PPHV and PPLV habitats. Significant correlations between ant community parameters and plant community parameters were also found. Few plants in the PPLV habitat may contribute to the lack of ants. High ant species richness at the BDZ habitat may be due to complex plant architecture. Results from this study suggest that ants are important focal species in tracking biotic recovery following disturbances.
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Ravi, Harshan, Olya Stringfield, Gustavo De Leon, Sandra Johnston, Russell Rockne, Behnam Badie, Christine E. Brown, Kristin Swanson, Robert Gatenby, and Natarajan Raghunand. "NIMG-74. MULTIPARAMETER MRI INVESTIGATION OF HIGH-GRADE GLIOMA RESPONSE TO CAR T CELL IMMUNOTHERAPY." Neuro-Oncology 21, Supplement_6 (November 2019): vi178. http://dx.doi.org/10.1093/neuonc/noz175.743.
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Abstract INTRODUCTION Immunotherapy with engineered CAR T cells is a promising new therapy for glioblastoma, for which predictive and prognostic biomarkers are needed to inform effective intervention. Recently, our group analyzed standard-of-care (SOC) MRI images of long-term and short-term glioblastoma survivors and identified six intratumoral “habitats” of which “Habitat 6” was correlated with survival at diagnosis in high-grade glioma. Based on the MRI characteristics of “Habitat 6”, viz. high enhancement and high edema, we hypothesized that it could be a marker of tumor immune infiltrates. We are studying longitudinal changes in tumor “habitat” composition on MRIs of subjects with recurrent high-grade glioma treated with CAR T cells engineered to target IL13Ra2. METHODS MRI scans of the brain were acquired in 6 subjects at 3.0 T at baseline and various times before and after initiation of CAR T cell therapy. FLAIR, T1W and T1W-CE MRI images were registered to T2W images and six intratumoral “habitats” were computed as per our recently published methodology. The six habitats generated at the end of the tumor segmentation process were: “Habitat 1” (low FLAIR, low enhancement), “Habitat 2” (high FLAIR, low enhancement), “Habitat 3” (low FLAIR, medium enhancement), “Habitat 4” (high FLAIR, medium enhancement), “Habitat 5” (low FLAIR, high enhancement), and “Habitat 6” (high FLAIR, high enhancement). RESULTS Analysis of temporal changes in the six “habitats” shows an initial increase in both “Habitat 4” and “Habitat 6” following CAR T cell therapy initiation. Subjects with higher absolute volumes of “Habitat 6” at the baseline (pre-treatment) showed longer overall survival. Overall survival is a function of absolute “Habitat 6” volume at baseline, its direction of change immediately post-therapy, the duration of any increase in “Habitat 6” post-treatment, and the “Habitat 6” to “Habitat 4” ratio. Additional subjects are being evaluated to further understand these preliminary observations.
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Qian, Tianlu, Yao Chi, Changbai Xi, Zhongqiu Li, and Jiechen Wang. "Changes in the Historical and Current Habitat Ranges of Rare Wild Mammals in China: A Case Study of Six Taxa of Small- to Large-Sized Mammals." Sustainability 12, no. 7 (March 31, 2020): 2744. http://dx.doi.org/10.3390/su12072744.
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Through history, the habitats of wild mammals have changed greatly in China. Habitat changes may reflect changes in the environment and human–wildlife conflicts. This study focused on how the habitat changed for six taxa of rare wild mammals (one family, one genus, and four species) in mainland China. Their historical and current habitats were estimated according to their historical and current presence occurrences and three sets of environmental data (climate data, topography data, and human activity data), using the Maximum Entropy Model. Then, spatial statistical methods were used to analyze the changes in their habitats, and how human activities have influenced changes in their habitat. The results suggest that the habitats of all six taxa of mammals have shrunk considerably, compared to their historical ranges. With regards to current or past habitats, on average, 68.3% of habitats have been lost. The Asian elephant, which is facing the most serious habitat losses, has lost 93.1% of its habitat. By investigating the relationship between the changes in habitats and the anthropogenic impacts for each taxa, human activities have an obvious negative influence on mammal habitats. The sensitivity of habitats to human activities varies among different mammals: the tiger, Asian elephant, Bactrian camel, and snub-nosed monkey are more sensitive to human activities than musk deer and Chinese water deer.
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Paterson, J. E., B. D. Steinberg, and J. D. Litzgus. "Generally specialized or especially general? Habitat selection by Snapping Turtles (Chelydra serpentina) in central Ontario." Canadian Journal of Zoology 90, no. 2 (February 2012): 139–49. http://dx.doi.org/10.1139/z11-118.
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Habitat selection is the disproportionate use of habitat compared with availability. Many studies have focused on specialists, but few have considered habitat selection in populations that are generalists, which can be composed of generalist individuals or individuals that specialize on different habitats. We tested habitat selection and individual specialization in a northern population of a supposed generalist, the Snapping Turtle ( Chelydra serpentina (L., 1758)), during the active season and winter using telemetry. Habitat selection was tested at two spatial scales by comparing random points to home ranges and turtle locations using Euclidean distances. Turtles selected home ranges from the habitats available in the population range. However, at the population level, all aquatic habitats were equally preferred, and the population behaved as a generalist owing to individuals specialized on different habitats. Over half of the individuals showed evidence of individual specialization on different habitat types. Turtles did not select habitat within home ranges during the active season, but overwintering turtles chose locations that were colder than haphazard stations in the same habitats, likely to reduce metabolic costs and the risk of acidosis. These findings have implications for the management of this species at risk and for understanding the evolution of resource generalization.
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Fernández, Guillermo, and David B. Lank. "Sex, Age, and Body Size Distributions of Western Sandpipers During the Nonbreeding Season With Respect to Local Habitat." Condor 108, no. 3 (August 1, 2006): 547–57. http://dx.doi.org/10.1093/condor/108.3.547.
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AbstractWe documented the local density and sex, age-class, and body size distributions of Western Sandpipers (Calidris mauri) among habitats at Bahía Santa María, northwestern Mexico, during the nonbreeding season. Three habitats were recognized: brackish flats, mangroves, and cattail marshes, which we ranked as richest to poorest in food resources and safest to most dangerous in predation danger. Western Sandpiper population structure differed among habitats. Bird densities were highest in brackish flats, the richest and safest habitat, and males and adults of both sexes were overrepresented. In cattail marshes, which appeared to be the poorest and most dangerous habitat, bird densities were lower, and the sex ratio and age ratios within each sex were more even. In mangroves, bird densities were similar to those in cattail marshes, but sex and age ratios were similar to those in brackish flats. Exposed culmen, an index of structural size, was not related to habitat use in either sex. Body mass of immature males was more variable than that of adults among habitats and immature males gained mass throughout the winter. Birds in brackish flats and mangroves were initially heavier, but tended to lose mass, whereas birds in cattail marshes were initially lighter, but tended to gain mass. Mass distributions thus converged in late winter. While the social and ecological causes and significance of differential sex and age-class distributions among habitats remain largely unquantified, evidence from this and previous studies suggests that nonbreeding population structure is a common phenomenon with important implications for migratory shorebirds.
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Lemieux Lefebvre, S., M. Landry-Cuerrier, and M. M. Humphries. "Identifying the critical habitat of Canadian vertebrate species at risk." Canadian Journal of Zoology 96, no. 4 (April 2018): 297–304. http://dx.doi.org/10.1139/cjz-2016-0304.
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Identification of critical habitat is central to major conservation laws protecting endangered species in North America and around the world. Yet the actual ecological research that is required to identify which habitats are critical to the survival or recovery of species is rarely discussed and poorly documented. Here we quantitatively assess the information and methods used to identify critical habitat in the recovery strategies of 53 vertebrates at risk in Canada. Of the critical habitat identifications assessed, 17% were based on habitat occupancy information, 28% on habitat characteristics and (or) functions, and 40% assessed habitat suitability by linking functional use and biophysical characteristics. However, only 15% of the recovery strategies we evaluated examined relationships between habitat and population viability, abundance, individual fitness, or survival. Furthermore, the breadth of evidence used to assess critical habitats was weaker among long-lived taxa and did not improve over time. Hence, although any approach used to identify critical habitat is likely to be a step in the right direction in minimally protecting and maintaining habitats supporting critical life-cycle processes, there is a persistent gap between the widely recognized importance of critical habitat and our ability to quantitatively link habitats to population trends and individual fitness.
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Thompson, Ian D. "The importance of superior-quality wildlife habitats." Forestry Chronicle 80, no. 1 (February 1, 2004): 75–81. http://dx.doi.org/10.5558/tfc80075-1.
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While animals may use many habitat types, relatively few are preferred and fewer yet are superior in quality (referring to individual fitness as the measure of quality). Historical reduction in habitat quality for some wildlife species has occurred such that we may now have limited reference to original superior-quality habitats. As time passes, managers may be unaware that superior habitats are slowly disappearing and that the slow but cumulative change is significant to a species at the population level. The perception of superior-quality habitat also changes with each successive generation of managers based on their experiences. This paper raises the concern that retrospective work may often be required to determine past forest habitats and associated animal populations to avoid the risk of falling into a trap of not recognizing ever-declining habitat quality through time and relegating animals to what is in fact much poorer quality habitat than those to which they are actually best adapted. Further, the relationship between relative abundance and habitat quality may often be uncertain owing to maladaptive habitat selection by animals, inappropriate survey timing or interannual population differences. While we have begun to appreciate aspects of habitat selection for many forest species, few data are yet available that relate selected habitats to fitness of individual animals. Hence, while we may have models to predict habitat use, considerable research remains to be done to be able to predict long-term sustainability of species in managed landscapes. Key words: habitat quality, forest management, sustainability, biodiversity
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Yan, Wen-Bo, Zhi-Gao Zeng, Hui-Sheng Gong, Xiang-Bo He, Xin-Yu Liu, Kai-Chuang Si, and Yan-Ling Song. "Habitat use and selection by takin in the Qinling Mountains, China." Wildlife Research 43, no. 8 (2016): 671. http://dx.doi.org/10.1071/wr16011.
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Context Understanding habitat use and selection by threatened ungulates is a crucial prerequisite to prioritise management areas and for developing effective conservation strategies. Aims The aim of our research was to determine the habitat use and selection of takins (Budorcas taxicolor) in the middle range of the Qinling Mountains, China. Methods The study was conducted from August 2013 to August 2015. Global positioning system (GPS) radio-tracking was used to monitor 10 collared takins to gain their location information. The Manly–Chesson selectivity index and Bonferroni-adjusted 95% confidence intervals were applied to determine which habitats were selected. Key results Habitat use and selection by takins showed obvious individual differences. At the landscape scale, all of the four most common habitat types were preferred by takins. However, all takins avoided artificially planted larch forest, and farmland and village. Available habitats within the home ranges also mostly included the four common habitat types. At the home-range scale, all individuals had significant habitat selectivity during the entire tracking period and each season. The habitat use and selection within the home range varied obviously with season and showed sexual differences to a certain extent. Conclusions The habitat selection by takins is scale-dependent. At the landscape scale, takins are most likely to occur at sites covered by forest. At both landscape and home-range scales, our results indicated that takins need more diverse forest habitats, but none of the four most common forest habitats is essential for survival of this species. Implications The present work has provided more insight into the habitat use and habitat selection of takins in mountainous forest landscapes. Many measures such as maintaining a diversity of forest habitats, avoiding habitat alteration by invasion of exotic plants, and increasing the area of available habitats by relocating the villages from within to outside of the reserve are recommended to conserve this large species.
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Both, Christiaan, Chris A. M. Van Turnhout, Rob G. Bijlsma, Henk Siepel, Arco J. Van Strien, and Ruud P. B. Foppen. "Avian population consequences of climate change are most severe for long-distance migrants in seasonal habitats." Proceedings of the Royal Society B: Biological Sciences 277, no. 1685 (December 16, 2009): 1259–66. http://dx.doi.org/10.1098/rspb.2009.1525.
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One consequence of climate change is an increasing mismatch between timing of food requirements and food availability. Such a mismatch is primarily expected in avian long-distance migrants because of their complex annual cycle, and in habitats with a seasonal food peak. Here we show that insectivorous long-distance migrant species in The Netherlands declined strongly (1984–2004) in forests, a habitat characterized by a short spring food peak, but that they did not decline in less seasonal marshes. Also, within generalist long-distance migrant species, populations declined more strongly in forests than in marshes. Forest-inhabiting migrant species arriving latest in spring declined most sharply, probably because their mismatch with the peak in food supply is greatest. Residents and short-distance migrants had non-declining populations in both habitats, suggesting that habitat quality did not deteriorate. Habitat-related differences in trends were most probably caused by climate change because at a European scale, long-distance migrants in forests declined more severely in western Europe, where springs have become considerably warmer, when compared with northern Europe, where temperatures during spring arrival and breeding have increased less. Our results suggest that trophic mismatches may have become a major cause for population declines in long-distance migrants in highly seasonal habitats.
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Powell, M., A. Accad, and A. Shapcott. "Where they are, why they are there, and where they are going: using niche models to assess impacts of disturbance on the distribution of three endemic rare subtropical rainforest trees of Macadamia (Proteaceae) species." Australian Journal of Botany 62, no. 4 (2014): 322. http://dx.doi.org/10.1071/bt14056.
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Species within the Macadamia genus (Proteaceae) are rare and threatened narrowly distributed inhabitants of subtropical lowland rainforests of eastern Australia. Despite their strong cultural links and economic importance as a source of germplasm for the macadamia nut industry, a comprehensive assessment of factors contributing to their conservation status, or the potential impacts of climate change, is lacking. We used maximum entropy models to identify the respective niche of the following three Macadamia species with overlapping extant distributions: M. integrifolia, M. ternifolia and M. tetraphylla. We used model predictions to identify and prioritise respective areas of habitat, together with change in geographic distribution of habitats between 1990 and 2070 climates. Results reveal considerable overlap in the geographic extent of habitat among the three species; however, the extent of current occupation of habitat by any individual species is limited. Relatively high levels of clearing of ecological communities strongly associated with M. integrifolia or M. ternifolia have occurred within the extent of their respective habitats, with M. tetraphylla less affected within the Queensland extent of its range. Response to climate change varies among the three species, with a general trend of shift in respective niche to areas that currently experience relatively high precipitation and lower temperature regimes.
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Jayawardana, J. M. C. K., Martin Westbrooke, Michael Wilson, and Cameron Hurst. "Macroinvertebrate communities in willow (Salix spp.) and reed beds (Phragmites australis) in central Victorian streams in Australia." Marine and Freshwater Research 57, no. 4 (2006): 429. http://dx.doi.org/10.1071/mf05139.
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Exotic willows (Salix spp.) are widespread riparian tree species of rivers in temperate Australia and New Zealand. Despite being considered as a weed of national significance, little is known about the habitat value of willows and the impact on aquatic biota of vegetation change following willow management programmes. Macroinvertebrate fauna in root habitats of willows and Phragmites australis habitats were examined in three central Victorian rivers to understand the effect of such littoral habitat changes on macroinvertebrates. Data were analysed using Partially Nested Factorial ANOVA with season, river and habitat as main effects. Habitat structure had a significant effect (P < 0.05) on macroinvertebrate community assemblage. However, effect of habitat was not consistent among seasons. The greatest community differences among habitats were observed during winter and least separation during autumn. Taxa responsible for community differences among habitats were also identified. Species richness and abundance did not show consistent variation among habitats over different rivers or seasons. This study provided some indication of the macroinvertebrate community changes that would take place in situations where riparian vegetation changes takes place from willows to P. australis.
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Belovsky, Gary E. "Insights for caribou/reindeer management using optimal foraging theory." Rangifer 11, no. 4 (October 1, 1991): 7. http://dx.doi.org/10.7557/2.11.4.987.
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Optimal foraging theory is useful to wildlife managers, because it helps explain the nutritional value of different habitats for wildlife species. Based upon nutritional value, the use of different habitats can be predicted, including how factors such as insect harassment, predation and migration might modify habitat selection. If habitat value and use can be understood, then changes in habitat availability which are of concern to wildlife managers can be assessed. The theory is used to address diet choice and habitat use of caribou/reindeer. Diet choice is examined in terms of lichen composition of the diet and is demonstrated to be a function of daily feeding time, food abundance and digestive capacity. The diet choice model is then used to assess the nutritional profitability of different habitats and which habitat should be preferred based upon nutritional profitability. Caribou/reindeer use of habitats is demonstrated to be easily modified by insect harassment and predation which change the nutritional profitability of habitats differentially. The same type of approach could be used to explain migratory behaviour; however, the needed parameter values are unavailable. The results of this analysis lead one to question some common conceptions about caribou/reindeer ecology.
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Liford, A. N., and K. K. Cecala. "Does riparian disturbance alter stream amphibian antipredator behaviors?" Canadian Journal of Zoology 95, no. 2 (February 2017): 75–79. http://dx.doi.org/10.1139/cjz-2016-0113.
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Ecological traps occur when a species makes maladaptive habitat-selection decisions. Human-modified environments including deforested riparian habitats can change how organisms respond to environmental cues. Stream amphibians alter their habitat selection in response to abiotic cues associated with riparian clearing, but little research exists to determine if behavioral shifts to abiotic cues may make them more susceptible to predation. To evaluate if deforested habitats create ecological traps, we studied habitat-selection behavior of larval Black-bellied Salamander (Desmognathus quadramaculatus (Holbrook, 1840)) when given conflicting environmental cues. We also evaluated the potential for learning or adaptation to cues in deforested reaches by evaluating individuals from forested and deforested reaches. We anticipated that individuals from deforested reaches would make adaptive antipredator choices when presented with well-lit habitat, whereas individuals from forested reaches would select shaded habitat closer to a predator. We found that habitat origin, light, and predator presence all interacted to influence habitat selection. Although individuals from forested habitats selected shaded environments, all observed individuals adaptively avoided a predator. Individuals from deforested reaches were more willing to enter well-lit habitat to avoid the predator. Despite documented declines of salamanders associated with forest removal, it appears that individuals are capable of making adaptive antipredator decisions in degraded habitats.
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Herdman, Emily J., and Karen E. Hodges. "Habitat Use by Nuttall’s Cottontails (Sylvilagus nuttallii nuttallii) at their Northern Range Edge (British Columbia, Canada)." Canadian Field-Naturalist 131, no. 2 (October 29, 2017): 133–40. http://dx.doi.org/10.22621/cfn.v131i2.1827.
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in Canada, Nuttall’s Cottontails (Sylvilagus nuttallii nuttallii) occur in southcentral British Columbia (BC), where they are federally listed as a species of special Concern due to their presumed small populations and limited distribution in fragmented habitats. Their habitat use and movement patterns are poorly known at this northern edge of their distribution. We used livetrapping, radio-collaring, and fecal pellet surveys to examine Nuttall’s Cottontails’ use of remaining patches of native habitat as well as use of human-impacted areas. Cottontails were present in low densities and only about half of presumably suitable patches of native sagebrush-steppe were occupied. Cottontails were more likely to occur in shrubby habitat, but at a fine scale cottontails used areas that had a lower density of shrubs and finer substrates. movement patterns differed significantly between areas of varying habitat quality, with longer movements in natural habitat. one radio-collared male cottontail used anthropogenic habitats adjacent to native habitat; this use corresponds with landowner reports. However, it is not clear whether Nuttall’s Cottontails are able to use anthropogenically-impacted areas to maintain populations or in areas where such habitats are not near native habitats. our results suggest that these animals are rare and occur primarily in remnant patches of shrub-steppe within BC.
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Mentil, Lorenzo, Corrado Battisti, and Giuseppe Maria Carpaneto. "The older the richer: significant increase in breeding bird diversity along an age gradient of different coppiced woods." Web Ecology 18, no. 2 (October 2, 2018): 143–51. http://dx.doi.org/10.5194/we-18-143-2018.
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Abstract. Forest structural complexity could be a good predictor of overall species diversity. Since tree harvesting has a negative effect on forest structure, it is important to analyse the effects of this disturbance on sensitive groups, as forest birds. In this study, we aimed to shed light on this aspect by analysing a set of univariate metrics in bird communities breeding in three coppiced forest habitats (coppiced of chestnut, coppiced of Turkey oak and high forest of beech) along a gradient in age classes. We hypothesised that, with increasing forest age, (i) breeding bird communities will progressively increase in diversity and, (ii) due to higher habitat heterogeneity due to coppicing, a higher species turnover in the first age classes could appear. In each forest habitat, all the metrics significantly increased, from recently coppiced to more mature forests, due to progressively higher availability of resources and niches along the gradient. When comparing paired forest habitats, abundance and richness were significantly different only in the two oldest age classes, highlighting that responses to different tree composition were more marked in the mature phase. In all forest habitats, species turnover (βw diversity) decreased progressively along the age gradient and was highest in the youngest age classes where many vegetation layers were present. Due to different coppice management practices, growth regime and consequent habitat heterogeneity, chestnuts showed a different pattern when compared to other forest habitats, with an increase in species turnover (βw diversity) at intermediate level. With increasing age of the forests, all the diversity metrics increased and species turnover decreased, highlighting the role of older forests as strategic habitats for highly structured bird communities.
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Garnick, S., J. Di Stefano, M. A. Elgar, and G. Coulson. "Do body size, diet type or residence time explain habitat use in a vertebrate herbivore community?" Australian Journal of Zoology 64, no. 2 (2016): 91. http://dx.doi.org/10.1071/zo15061.
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Many theories attempt to explain patterns of community organisation among large herbivores. We explored the role of body size, diet type and residence time on habitat use in a community comprising four metatherians (western grey kangaroo, Macropus fuliginosus; eastern grey kangaroo, M. giganteus; red-necked wallaby, Notamacropus rufogriseus; swamp wallaby, Wallabia bicolor) and two eutherians (red deer, Cervus elaphus; European rabbit, Oryctolagus cuniculus) in south-eastern Australia. We used camera traps to estimate habitat occupancy, quantified habitat specialisation using relative entropy, and ran regressions using percentage grass consumed, log(mass) and log(time at site) as predictor variables and relative entropy as the response. If body size influenced habitat use, we predicted smaller species would occupy fewer habitats. If diet type influenced habitat use, we predicted intermediate feeders would use more habitats. If the time that a species had been present at a site predicted community organisation, newer species would use more habitats. None of these theories explained habitat use in our community. Red deer used a narrower range of habitats than expected, perhaps due to the poor suitability of habitats available in the Grampians. While interactions between our hypotheses are likely to be important, the body size model deserves further attention in this community.
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Caddy, John F. "Why do assessments of demersal stocks largely ignore habitat?" ICES Journal of Marine Science 71, no. 8 (April 19, 2013): 2114–26. http://dx.doi.org/10.1093/icesjms/fss199.
Full textAbstract:
AbstractThe divergence between most stock assessments and studies in marine ecology is characterized by the low priority usually given to assessing the holding capacity of marine habitats. Habitats of high structural complexity are relatively uncommon in shelf waters, are contagiously distributed, and are damaged incidentally by bottom-towed gear. Structurally complex habitats are used by many demersal fish and crustaceans for predation abatement and as a site for feeding forays. Successive life-history stages typically migrate through several structurally complex habitats which recent studies show often to have fractal properties. One consequence of fractal structures as cover is a rapid reduction of protection from predators with growth in size: migration is the only response possible when further growth of the recruiting age class renders individuals in that habitat vulnerable to predation. A common feature of structurally complex habitats with high vulnerability at size is the occurrence of population bottlenecks. It is suggested that identifying and rectifying shortages of structured habitat, and eliminating habitat bottlenecks, will be effective in stock enhancement. This will require placing strict spatial constraints on the operation of bottom gear. This paper reviews new methods of estimating juvenile predation mortality, including mortality-at-age and mortality-at-life-history stage, which depend on the fractal characteristics of structurally complex habitats.
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Sievers, Katie T., Rene A. Abesamis, Abner A. Bucol, and Garry R. Russ. "Unravelling Seascape Patterns of Cryptic Life Stages: Non-Reef Habitat Use in Juvenile Parrotfishes." Diversity 12, no. 10 (September 30, 2020): 376. http://dx.doi.org/10.3390/d12100376.
Full textAbstract:
Juvenile fish often use alternative habitats distinct from their adult phases. Parrotfishes are an integral group of coral reef fish assemblages, are targeted in fisheries, are sensitive to reef disturbances, and have been documented as multiple-habitat users. Considering the abundance of research conducted on parrotfishes, very little is known about their juvenile ecology at the species level due to their cryptic and variable coloration patterns. We collected juvenile parrotfishes in non-reef habitats (macroalgal beds, seagrass beds, and lagoons) in the Philippines and used DNA analysis to determine species composition. The results were then compared with data on adult parrotfish abundance from underwater visual census (UVC) surveys in coral reef and non-reef habitats. Collections identified 15 species of juvenile parrotfishes in non-reef habitats, and of these, 10 were also recorded in UVCs as adults. Informed by adult surveys, 42% of the 19 parrotfish species observed as adults were classified as multi-habitat users based on their presence in coral reef and non-reef habitats. When accounting for the occurrence of species as juveniles in non-reef habitats, 93% of the species collected as juveniles would be considered multi-habitat users. Species identified as juveniles in non-reef habitats comprised 50% of the average adult parrotfish density on coral reefs and 58–94% in non-reef habitats. The species richness of juveniles in non-reef habitats was greater than that of adults occupying the same habitats, and the most common adult species observed in UVCs was not collected as juveniles in non-reef habitats. Finally, UVC suggested that 97% of juvenile parrotfish <10-cm total length was present in non-reef habitats compared to coral reefs. These results provide further evidence for ontogenetic movement across habitat boundaries for parrotfish species in a diverse and highly connected tropical seascape. This is one of the few studies to quantify links between nursery and adult habitat in parrotfishes, highlighting the importance of including non-reef habitats in ecological studies of an iconic group of coral reef fish.
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Lee, Chen-Lu, Colin K. C. Wen, Yen-Hsun Huang, Chia-Yun Chung, and Hsing-Juh Lin. "Ontogenetic Habitat Usage of Juvenile Carnivorous Fish Among Seagrass-Coral Mosaic Habitats." Diversity 11, no. 2 (February 18, 2019): 25. http://dx.doi.org/10.3390/d11020025.
Full textAbstract:
Seagrass beds and coral reefs are both considered critical habitats for reef fishes, and in tropical coastal regions, they often grow together to form “mosaic” habitats. Although reef fishes clearly inhabit such structurally complex environments, there is little known about their habitat usage in seagrass-coral mosaic habitats. The goal of this study was to examine potential factors that drive habitat usage pattern by juvenile reef fishes. We quantified (1) prey availability, (2) potential competitors, and 3) predators across a gradient of mosaic habitats (n = 4 habitat types) for four dominant carnivorous fishes (lethrinids and lutjanids) in the main recruitment season at Dongsha Island, South China Sea. We found that the coral-dominated habitats had not only a higher availability of large crustacean prey but also a higher abundance of competitors and predators of juvenile fishes. Food availability was the most important factor underlying the habitat usage pattern by lethrinids and lutjanids through ontogeny. The predation pressure exhibited a strong impact on small juvenile lethrinids but not on larger juveniles and lutjanids. The four juvenile fishes showed distinct habitat usage patterns through ontogeny. Collectively, mosaic habitats in the back reef system may be linked to key ontogenetic shifts in the early life histories of reef fishes between seagrass beds and coral reefs.
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Carlisle, Aaron B., Kenneth J. Goldman, Steven Y. Litvin, Daniel J. Madigan, Jennifer S. Bigman, Alan M. Swithenbank, Thomas C. Kline, and Barbara A. Block. "Stable isotope analysis of vertebrae reveals ontogenetic changes in habitat in an endothermic pelagic shark." Proceedings of the Royal Society B: Biological Sciences 282, no. 1799 (January 22, 2015): 20141446. http://dx.doi.org/10.1098/rspb.2014.1446.
Full textAbstract:
Ontogenetic changes in habitat are driven by shifting life-history requirements and play an important role in population dynamics. However, large portions of the life history of many pelagic species are still poorly understood or unknown. We used a novel combination of stable isotope analysis of vertebral annuli, Bayesian mixing models, isoscapes and electronic tag data to reconstruct ontogenetic patterns of habitat and resource use in a pelagic apex predator, the salmon shark ( Lamna ditropis ). Results identified the North Pacific Transition Zone as the major nursery area for salmon sharks and revealed an ontogenetic shift around the age of maturity from oceanic to increased use of neritic habitats. The nursery habitat may reflect trade-offs between prey availability, predation pressure and thermal constraints on juvenile endothermic sharks. The ontogenetic shift in habitat coincided with a reduction of isotopic niche, possibly reflecting specialization upon particular prey or habitats. Using tagging data to inform Bayesian isotopic mixing models revealed that adult sharks primarily use neritic habitats of Alaska yet receive a trophic subsidy from oceanic habitats. Integrating the multiple methods used here provides a powerful approach to retrospectively study the ecology and life history of migratory species throughout their ontogeny.
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Bobadoye, Bridget O., Paul N. Ndegwa, Lucy Irungu, and Ayuka T. Fombong. "Vulnerable Habitats Alter African Meliponine Bee’s (Hymenoptera: Apidae) Assemblages in an Eastern Afromontane Biodiversity Hotspot." International Journal of Insect Science 9 (January 1, 2017): 117954331770978. http://dx.doi.org/10.1177/1179543317709788.
Full textAbstract:
Habitat degradation has over time formed synergy with other factors to contribute to dwindling populations of both fauna and flora by altering their habitats. The disturbance of natural habitats affects the diversity of both vertebrates and invertebrates by altering both feeding and nesting sites for which organisms are known to depend on for survival. Little is known of the extent to which vulnerable habitats could shape the diversity of most indigent pollinators such as African meliponine bee species in tropical ecosystems. This study was conducted to determine how disturbance could shape the natural occurrence of African meliponine bee species in different ecological habitats of Taita Hills, leading to changes in their diversity. A total of four species depicted by the Renyi diversity profile was recorded in five of the six main habitat types surveyed, and a further extrapolation with Shannon index ( EH) also predicted the highest species richness of 4.24 in a deciduous habitat type. These meliponine bee species ( Hypotrigona gribodoi, Hypotrigona ruspolii, Meliponula ferruginea (black), and Plebeina hildebrandti) were observed to be unevenly distributed across all habitats, further indicating that mixed deciduous habitat was more diverse than acacia-dominated bush lands, grasslands, and exotic forest patches. Geometric morphometrics categorized all four meliponine bee species into two major clusters—cluster 1 ( H gribodoi, H ruspolii, M ferruginea (black)) and cluster 2 ( P hildebrandti)—and further discriminated populations against the 4 potential habitats they are likely to persist or survive in. Each habitat appeared to consist of a cluster of subpopulations and may possibly reveal ecotypes within the four meliponine populations. This has revealed that unprecedented conversions of natural habitats to agroecosystems are a key driving factor causing increased habitat isolation and vulnerability in this Afromontane region which may potentially distort local assemblages of native pollinators, such as meliponine bee species.
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Brown, Timothy J., and Paul Handford. "Sound Design for Vocalizations: Quality in the Woods, Consistency in the Fields." Condor 102, no. 1 (February 1, 2000): 81–92. http://dx.doi.org/10.1093/condor/102.1.81.
Full textAbstract:
AbstractThe acoustic adaptation hypothesis (AAH) predicts that vocalizations intended for unambiguous long range communication should possess amplitude modulation (AM) characteristics such that the temporal patterning of amplitude degrades less than alternative patterns during transmission through native habitat. The specific predictions are that open habitat signals should be structured as rapid AM trills, whereas closed habitat signals should be structured as low-rate AM tonal whistles. To investigate the benefit of trill- and whistle-structured signals in open and closed habitats, respectively, a high and low carrier frequency set of four synthetic signals which ranged from rapid AM trills to low rate AM whistles were transmitted 3 hours after sunrise through five different habitat types ranging from closed mature forest to open grassland. Results indicate that, on average, whistles degrade less than trills in both habitats. Trills benefit in open habitats through their tendency to be received with a more consistent quality than whistles. Such differences in transmission consistency among AM patterns are not found in closed habitats. While not degrading less on average, lower frequency signals are received with a more consistent quality than are higher frequency signals of the same AM structure, in both open and closed habitats.
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Fort, Kevin T., and Ken A. Otter. "Effects of Habitat Disturbance on Reproduction in Black-Capped Chickadees (Poecile Atricapillus) in Northern British Columbia." Auk 121, no. 4 (October 1, 2004): 1070–80. http://dx.doi.org/10.1093/auk/121.4.1070.
Full textAbstract:
Abstract Avian species that persist in breeding in disturbed habitats are often thought to be less affected by disturbance than habitat specialists lost following disturbances, yet there is growing evidence that human-altered environments may negatively affect reproductive behavior and nest success of those generalists as well. We compared nest success of Blackcapped Chickadees (Poecile atricapillus) in two adjacent habitats: a mature mixed-wood forest (undisturbed) and a forest regenerating after logging (disturbed). Despite similar breeding densities, proportion of nests that successfully fledged young was lower in the disturbed habitat than in the undisturbed habitat. Abandonment was the most common cause of nest failure. A within-habitat comparison of the social rank of birds revealed that low-ranking birds had lower nest success than high-ranking birds in the disturbed, but not in the undisturbed, habitat. Clutch size and brood size of nests that progressed to the point of hatch did not differ significantly between habitats. Average total number of fledglings produced per pair, though not significantly different, was suggestively lower in the disturbed habitat. Across habitats, nests situated in snags with lower amounts of internal decay were more successful. Successful nests were also located in sites with higher canopy height, low understory density below 1 m, and higher understory density between 2 and 3 m—all attributes generally associated with undisturbed, mature forests in the region. Our results provide evidence that disturbed habitats may represent poor-quality habitat for this forest generalist, and that habitat quality differentially affects individuals, depending on their dominance rank.
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Dufek, Matias I., Dario D. Larrea, Miryam P. Damborsky, and Pablo R. Mulieri. "The Effect of Anthropization on Sarcophagidae (Diptera: Calyptratae) Community Structure: An Assessment on Different Types of Habitats in the Humid Chaco Ecoregion of Argentina." Journal of Medical Entomology 57, no. 5 (April 20, 2020): 1468–79. http://dx.doi.org/10.1093/jme/tjaa071.
Full textAbstract:
Abstract Sarcophagidae (Diptera) are of great interest from a veterinary, medical, and forensic viewpoint, and are potential bioindicators for environmental impact assessments. In this study, we evaluated changes in abundance, species richness, and diversity of flesh flies in different habitat types in the Humid Chaco ecoregion of South America: 1) anthropized habitats: urban, cattle farm, and alfalfa crop, and 2) natural habitats: savanna and forest. We hypothesized that sarcophagid fly community parameters are affected by the anthropization and that spatial turnover will contribute more to the overall beta diversity than nestedness between habitats. In each habitat, samplings were conducted monthly from March 2015 to February 2016 in 25 sites, 5 per habitat, totaling 300 independent samples at the end of the study. We collected 5,790 Sarcophagidae (55 species). Community parameters of Sarcophagidae were evaluated and compared. The ecological effects of anthropization and habitat type were observed in the present study. As expected, our results showed the highest abundance, species richness, and diversity in the savanna and forest habitats (natural), whereas the lowest values were registered in the urban and alfalfa crop habitats, supporting the hypotheses of anthropization as the main driver of diversity loss. In addition, sarcophagid assemblages differed between all habitats and the overall dissimilarity was structured by spatial turnover. The main conclusion of this research is that flesh fly community structure is greatly affected by anthropization and habitat type, and this would be related to canopy cover and microclimate conditions of each environment.
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Osuka, Kennedy, Marc Kochzius, Ann Vanreusel, David Obura, and Melita Samoilys. "Linkage between fish functional groups and coral reef benthic habitat composition in the Western Indian Ocean." Journal of the Marine Biological Association of the United Kingdom 98, no. 2 (October 10, 2016): 387–400. http://dx.doi.org/10.1017/s0025315416001399.
Full textAbstract:
Benthic habitat composition is a key factor that structures assemblages of coral reef fishes. However, natural and anthropogenic induced disturbances impact this relationship. This study investigates the link between benthic habitat composition and fish functional groups in four countries in the Western Indian Ocean (WIO). Benthic composition of 32 sites was quantified visually from percentage cover of hard and soft corals, rubble, turf, fleshy and crustose coralline algae. At each site, abundance of 12 coral-associated fish functional groups in 50 × 5 m transects was determined. Cluster analysis characterized reefs based on benthic cover and revealed five habitat types (A, B, C, D and E) typified by decreasing cover of hard corals, increasing cover of turf and/or fleshy algae and differences in benthic diversity. Habitat type A was present in all four countries. Other habitats types showed geographic affiliations: notably Comoros sites clustered in either habitats B or E, northern Madagascar had B, C and D type habitats, whereas sites in central Tanzania and northern Mozambique had habitats D and E. Fish functional groups showed significant linkages with some habitat types. The abundances of corallivores, invertivores, detritivores and grazers were higher in habitat B, whereas planktivores and small excavators showed lower abundances in the same habitat. These linkages between benthic habitat types and fish functional groups are important in informing priority reefs that require conservation and management planning.
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Arifianti, Eka Nur, Husain Latuconsina, and Hasan Zayadi. "Composition and Density of Gastropode in Mangrove Habitat of Banyuurip, Ujung Pangkah - Gresik." Agrikan: Jurnal Agribisnis Perikanan 14, no. 1 (April 4, 2021): 65–72. http://dx.doi.org/10.29239/j.agrikan.14.1.65-72.
Full textAbstract:
Gastropods are one of the biota that live in association with mangrove habitat. This study aims to compare the species composition and structure of the gastropod community in different mangrove habitats. This research was conducted in Banyuurip Mangrove Center (BMC), Ujung Pangkah-Gresik during July-August 2020. Determination of the observation station purposively based on physical differences in mangrove habitat. Estimation of mangrove and gastrode density by systematic sampling method using belt transects. There were 12 mangrove species with the highest number of species in the coastal mangrove habitat, with the highest species composition and density of Avicennia marina. The highest mangrove density was found in coastal mangrove habitats for all criteria. The number of gastropods found were 2,171 specimens belonging to 15 species, 5 families and 5 orders. The highest number of species, families and orders in coastal mangrove habitat were 1,191 specimens, 11 species from 5 families and 5 orders, the lowest was in estuarine mangrove habitat as many as 980 specimens from 9 species, 2 families and 2 orders. Densities of gastropods differ between mangrove habitats, with the highest density in coastal mangrove habitats and the lowest in estuarine mangrove habitats. The composition and density of the highest gastropods species in the estuary mangrove habitat is Cassidula aurisfelis and in the coastal mangrove habitat is Pirenella cingulata. The importance of conservation and rehabilitation efforts for mangroves that have been degraded to support the gastropods associated in it.
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Lustyk, Pavel, and Petr Vahalík. "Threat Degree Classification According to Habitat Quality: A Case Study from the Czech Republic." Forests 12, no. 1 (January 14, 2021): 85. http://dx.doi.org/10.3390/f12010085.
Full textAbstract:
Important sources of information in the field of nature protection are red lists, which define the degree of threat to individual species. In practice, an assessment of the quality of the habitats in which a species occurs is used to a very limited extent in the preparation of red lists of vascular plants. At the same time, this parameter is usually essential to determine their degree of threat. At present, habitat quality data are available for the territory of the Czech Republic; these were obtained during Natura 2000 habitat mapping in the years 2000–2019. In this paper we propose the use of habitat quality data to determine the degree of threat to selected species of vascular plants and to compile a national red list. Nine plant species from three habitat types were selected for this study: meadows and wetland habitats in the alluvium of large rivers (Cardamine matthioli Moretti, Gratiola officinalis L., Teucrium scordium L.), fen habitats (Carex appropinquata Schumach., C. cespitosa L., C. lepidocarpa Tausch) and ecotone shrub habitats (Rosa agrestis Savi, R. micrantha Borrer ex Sm., R. spinosissima L.). For these species, the quality of the habitats in which they occur was analysed and grid maps were created, which present (1) the level of knowledge of habitat quality and (2) the average habitat quality. The results were compared with the degree of threat in the current national red list. Habitat quality analysis should also be used in the future to detect threatened species, which today are outside the red list and this assessment may be useful in compiling another updated red list of vascular plants of the Czech Republic.
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Wright, Jeffrey T., James E. Byers, Loni P. Koukoumaftsis, and Paul E. Gribben. "Differences in anti-predator traits of a native bivalve following invasion by a habitat-forming seaweed." Marine and Freshwater Research 63, no. 3 (2012): 246. http://dx.doi.org/10.1071/mf11184.
Full textAbstract:
Invasive habitat-forming species cause large changes to the abiotic environment, which may lead to lethal and sublethal effects on native fauna. In this study, we tested whether morphological anti-predator traits of an infaunal bivalve, Anadara trapezia, differed between areas invaded by the habitat-forming seaweed Caulerpa taxifolia and uninvaded habitats in estuaries in New South Wales, Australia. Caulerpa changes the abiotic environment in ways that may affect traits of native species. In particular, there is lower water flow, lower dissolved oxygen in the water and sediments are more silty and anoxic than in unvegetated habitat. To test our hypotheses, we collected Anadara from Caulerpa and uninvaded habitats and measured shell thickness, shell strength and resistance to opening of valves. We found that all three traits were reduced in Anadara from Caulerpa habitat compared with Anadara from uninvaded habitats. These findings are consistent with the idea that trait modifications in native fauna in response to invasive habitat-forming species can potentially increase susceptibility to predation.
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Skewes, T. D., D. M. Dennis, C. R. Pitcher, and B. G. Long. "Age structure of Panulirus ornatus in two habitats in Torres Strait, Australia." Marine and Freshwater Research 48, no. 8 (1997): 745. http://dx.doi.org/10.1071/mf97191.
Full textAbstract:
The lobster population in Torres Strait, Australia, is made up of juvenile and sub-adult lobsters up to two years old (1+ and 2+), with some 3-year-old (3+) male lobsters. These lobsters live either on shallow reefs or in the deeper areas between reefs. Intensive surveys of lobsters in these two habitats showed that 1+ lobsters live only in the deep habitat, 2+ lobsters live in the deep habitat and on shallow reefs, and 3+ male lobsters live mainly on shallow reefs. In the deep habitat, lobsters were found mainly in areas that had rock and rubble substratum. There may be little movement of lobsters onto or off the shallow reefs during the winter months and 1+ lobsters probably recruit onto the shallow reefs so