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Carvalho, Mônica Canaan, Luciano Cavalcante de Jesus França, Isaira Leite e Lopes, Laís Almeida Araújo, José Márcio de Mello, and Lucas Rezende Gomide. "ALGORITMOS DE APRENDIZAGEM DE MÁQUINA NA MODELAGEM DA DISTRIBUIÇÃO POTENCIAL DE HABITATS DE ESPÉCIES ARBÓREAS." Nativa 7, no. 5 (September 12, 2019): 600. http://dx.doi.org/10.31413/nativa.v7i5.7214.
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O estudo teve como objetivo avaliar três métodos de aprendizagem de máquina (árvore de decisão-J48, random forest e redes neurais artificias), na modelagem da distribuição de dez espécies arbóreas mais abundantes em uma sub-bacia do rio São Francisco (MG). Utilizaram-se dados provenientes do Inventário Florestal de Minas, com total de 77 fragmentos amostrados e 2.234 parcelas, nas quais foram computadas a presença/ausência de cada espécie. Empregaram-se 12 variáveis ambientais categóricas procedentes do Zoneamento Ecológico Econômico de Minas Gerais (ZEE/MG), além de variáveis relacionadas ao balanço hídrico do solo (evapotranspiração atual e potencial, aridez e índice alpha). A parametrização dos três algoritmos para as dez espécies selecionadas foi feita com o auxílio do algoritmo cv parameter do software WEKA. Os resultados mostram que os algoritmos testados apresentaram desempenhos estatisticamente iguais em 60% das espécies arbóreas. Os algoritmos random forest e multilayer perceptron foram estatisticamente iguais para a espécie Eugenia dysenterica, sendo superiores ao algoritmo J48. Contudo, o algoritmo random forest foi superior aos demais para as três espécies do gênero Qualea. Conclui-se que o algoritmo random forest apresentou-se como o mais robusto para a modelagem da distribuição potencial de habitat de espécies arbóreas.Palavras-chave: inteligência artificial; árvore de decisão; random forest; redes neurais artificiais. MACHINE LEARNING ALGORITHMS FOR MODELING THE POTENTIAL DISTRIBUTION HABITAT OF TREE SPECIES ABSTRACT: The aim of the present study was to evaluate three methods of machine learning (decision tree-J48, random forest and artificial neural networks) to model the potential habitat distribution of the ten most abundant tree species of the São Francisco river watershed. The presence/absence tree species data were from 77 fragments sampled with 2,234 plots. We used 12 categorical environmental variables from the Economic Ecological Zoning of Minas Gerais (ZEE/MG), as well as variables related to soil water balance (current and potential evapotranspiration, aridity and alpha index). The parameterization of the three algorithms was done with cv parameter algorithm of the WEKA software. The results showed the applied algorithms were statistically similar for 60% of the tree species. The random forest and multilayer perceptron algorithms were statistically similar considering the Eugenia dysenterica and superior to J48 algorithm. However, the random forest algorithm was superior to the other for the three species of Qualea genera. The conclusion is the random forest was the most robust model for the potential distribution habitat of tree species.Keywords: artificial intelligence; decision trees; random forest; artificial neural networks.
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Harris, Peter T., Thomas C. L. Bridge, Robin J. Beaman, Jody M. Webster, Scott L. Nichol, and Brendan P. Brooke. "Submerged banks in the Great Barrier Reef, Australia, greatly increase available coral reef habitat." ICES Journal of Marine Science 70, no. 2 (November 29, 2012): 284–93. http://dx.doi.org/10.1093/icesjms/fss165.
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Abstract Harris, P. T., Bridge, T. C. L., Beaman, R. J., Webster, J. M., Nichol, S. L., and Brooke, B. P. 2013. Submerged banks in the Great Barrier Reef, Australia, greatly increase available coral reef habitat. – ICES Journal of Marine Science, 70: 284–293. Anthropogenic global ocean warming is predicted to cause bleaching of many near-sea-surface (NSS) coral reefs, placing increased importance on deeper reef habitats to maintain coral reef biodiversity and ecosystem function. However, the location and spatial extent of many deep reef habitats is poorly known. The question arises: how common are deep reef habitats in comparison with NSS reefs? We used a dataset from the Great Barrier Reef (GBR) to show that only about 39% of available seabed on submerged banks is capped by NSS coral reefs (16 110 km2); the other 61% of bank area (25 600 km2) is submerged at a mean depth of around 27 m and represents potential deep reef habitat that is spatially distributed along the GBR continental shelf in the same latitudinal distribution as NSS reefs. Out of 25 600 km2 of submerged bank area, predictive habitat modelling indicates that more than half (around 14 000 km2) is suitable habitat for coral communities.
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Lind, P. R., B. J. Robson, B. D. Mitchell, and T. G. Matthews. "Can sand slugs in rivers deliver conservation benefits? The biodiversity value of tributary junction plug wetlands in the Glenelg River, Australia." Marine and Freshwater Research 60, no. 5 (2009): 426. http://dx.doi.org/10.1071/mf08175.
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Restoration works are carried out to alleviate human impacts and improve habitats within ecosystems. However, human impacts may also create new (anthropogenic) habitat for species to exploit. A dilemma arises when proposed restoration works would remove anthropogenic habitat and the assemblages it supports. Sediment input into the Glenelg River has formed tributary junction plug wetlands at confluences. Sand slug removal is proposed as part of river rehabilitation, but would also drain plug wetlands. We sampled four plug wetland, four river run and three river pool sites to determine whether plug wetlands influence water quality and add to the biodiversity of macroinvertebrates in the Glenelg River. Water quality and macroinvertebrate diversity were similar in plug wetlands, river runs and river pools. Assemblages were distinct among all sites, regardless of type, so there was no characteristic ‘plug-wetland fauna’. Therefore, although removal of plug wetlands would not cause a dramatic loss of invertebrate biodiversity, it would destroy anthropogenic habitat that supports a similar range of species to natural habitats in a river subject to multiple degrading processes. Gains from rehabilitation should be weighed against the value of anthropogenic habitat and the extent of similar habitat lost elsewhere in the ecosystem.
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Witt, Jonathan DS, and Paul DN Hebert. "Cryptic species diversity and evolution in the amphipod genus Hyalella within central glaciated North America: a molecular phylogenetic approach." Canadian Journal of Fisheries and Aquatic Sciences 57, no. 4 (April 1, 2000): 687–98. http://dx.doi.org/10.1139/f99-285.
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Many benthic freshwater invertebrates are strong candidates for diversification as a result of their short generation times, the divergent selection pressures that they encounter across habitat gradients, and the insular nature of aquatic environments. We analysed populations of the amphipod crustacean Hyalella azteca s.l. from habitats in Ontario, Wisconsin, New Brunswick, and the Yukon Territory. Combined analysis of allozymes and the mitochondrial cytochrome c oxidase I gene revealed that H. azteca is a complex of at least seven species showing marked genetic, but little morphological divergence. Two or more co-occurring species were detected in at least 15 of the 24 habitats. Evidence suggests that diversification has arisen as a consequence of both isolation in different glacial refugia and habitat specialization. A recent origin for the subgenus Hyalella, following the formation of the Isthmus of Panama, is improbable; the subgenus appears to have originated as early as the mid-Miocene.
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Møller, Anders Pape, Canwei Xia, Bo ZHou, Xianli Che, Xingzhi CHu, Changzhang Feng, Karsten Laursen, et al. "Comparative urbanization of birds in China and Europe based on birds associated with trees." Current Zoology 65, no. 6 (March 4, 2019): 617–25. http://dx.doi.org/10.1093/cz/zoz007.
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AbstractUrbanization effects on living organisms are spatially heterogeneous. Here we quantified the abundance of birds per tree in forested urban and rural habitats for 85,829 trees mainly in China and Europe. A population model was based on the assumption that: 1) birds have a normally distributed habitat preference; 2) an increase in population size linked to the habitat preference; 3) a population size dependent on the habitat preference; and 4) the removal of a certain fraction of individuals giving rise to extinction. We tested for large-scale differences in the impact of urbanization on the frequency distribution of the difference in abundance between urban and rural habitats in China and parts of Europe. The difference in the frequency distribution of urban population density of birds in trees minus rural population density of birds in trees in China and Europe was statistically significant, suggesting that the abundance of birds differed between trees in urban and rural habitats, but more so in China than in Europe. We hypothesize that more pronounced differences in China than in Europe may have arisen due to the Four Pests Campaign in 1958–1962 that resulted in death of hundreds of millions of birds (mainly tree sparrows Passer montanus, but also numerous other less common species that were starting to become urbanized around 1960). Species that were less common in 1960 could not sustain reductions in population size in urban areas and hence these species are still rare or absent in urban areas today 60 years later.
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Crews, Sarah C., Erika L. Garcia, Joseph C. Spagna, Matthew H. Van Dam, and Lauren A. Esposito. "The life aquatic with spiders (Araneae): repeated evolution of aquatic habitat association in Dictynidae and allied taxa." Zoological Journal of the Linnean Society 189, no. 3 (December 17, 2019): 862–920. http://dx.doi.org/10.1093/zoolinnean/zlz139.
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Abstract Despite the dominance of terrestriality in spiders, species across a diverse array of families are associated with aquatic habitats. Many species in the spider family Dictynidae are associated with water, either living near it or, in the case of Argyroneta aquatica, in it. Previous studies have indicated that this association arose once within the family. Here we test the hypothesis of a single origin via the broadest phylogeny of dictynids and related ‘marronoids’ to date, using several taxa that were not previously sampled in molecular analyses to provide the first quantitative test of the hypothesis put forth by Wheeler et al. (2016). We sampled 281 terminal taxa from 14 families, assembling a matrix with 4380 total base pairs of data from most taxa. We also assembled an atlas of morphological traits with potential significance for both ecology and taxonomy. Our resulting trees indicate that an aquatic habitat association has arisen multiple times within dictynids. Dictynidae and the genus Dictyna are polyphyletic and the genera Lathys and Cicurina remain unplaced. A review of aquatic habitat associations in spiders indicates that it occurs in members of at least 21 families. With our morphological atlas, we explore characters that have been implicated in aiding an aquatic lifestyle, which in the past may have caused confusion regarding taxon placement. Our results indicate that not all spiders with traits thought to be useful for aquatic habitat associations occupy such habitats, and that some spider taxa lacking these traits are nonetheless associated with water.
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Lüscher, Beatrice, Lutz Dalbeck, and Dagmar Ohlhoff. "Beaver ponds as habitat of amphibian communities in a central European highland." Amphibia-Reptilia 28, no. 4 (2007): 493–501. http://dx.doi.org/10.1163/156853807782152561.
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Abstract The Eurasian beaver Castor fiber, formerly occurred across the Palaearctic, but was nearly eradicated in the 19th century. Due to reintroductions in the 20th century, beaver populations are increasing and now extend into highland areas. Natural still waters are scarce in highlands of Central Europe. Therefore the question arises, “Are beaver ponds essential habitats for amphibians?”, especially since fishes, predators of amphibian larval stages, also inhabit beaver ponds. We investigated the amphibian fauna of one typical valley in the Eifel, that was colonized by beavers in 1981, and compared areas with and without beaver ponds. All anuran species of the region occupied beaver ponds, including species that were absent (Alytes obstetricans, Bufo bufo and Rana kl. esculenta) or rare (Rana temporaria) in natural waters. Alytes obstetricans obviously benefited from pond construction and the removal of trees by beavers which leads to sunny plots along the slopes of the valley, crucial habitat for this species. The urodelans Salamandra salamandra, Triturus alpestris and Triturus helveticus were widely distributed in beaver ponds. Our results show clearly, that beaver altered landscapes offer high quality habitats for amphibians in our study area. Due to a considerable increase of habitat heterogeneity in impounded streams, the predator Salmo trutta was not able to extirpate the amphibian fauna. We conclude that the historic effects of beavers need to be considered for a proper understanding of patterns of amphibian distribution and habitat requirements in Central European Highlands. Furthermore, beaver-created landscapes will be of future relevance for conservation of endangered species, like Alytes obstetricans.
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Kopps, Anna M., Corinne Y. Ackermann, William B. Sherwin, Simon J. Allen, Lars Bejder, and Michael Krützen. "Cultural transmission of tool use combined with habitat specializations leads to fine-scale genetic structure in bottlenose dolphins." Proceedings of the Royal Society B: Biological Sciences 281, no. 1782 (May 7, 2014): 20133245. http://dx.doi.org/10.1098/rspb.2013.3245.
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Socially learned behaviours leading to genetic population structure have rarely been described outside humans. Here, we provide evidence of fine-scale genetic structure that has probably arisen based on socially transmitted behaviours in bottlenose dolphins ( Tursiops sp.) in western Shark Bay, Western Australia. We argue that vertical social transmission in different habitats has led to significant geographical genetic structure of mitochondrial DNA (mtDNA) haplotypes. Dolphins with mtDNA haplotypes E or F are found predominantly in deep (more than 10 m) channel habitat, while dolphins with a third haplotype (H) are found predominantly in shallow habitat (less than 10 m), indicating a strong haplotype–habitat correlation. Some dolphins in the deep habitat engage in a foraging strategy using tools. These ‘sponging’ dolphins are members of one matriline, carrying haplotype E. This pattern is consistent with what had been demonstrated previously at another research site in Shark Bay, where vertical social transmission of sponging had been shown using multiple lines of evidence. Using an individual-based model, we found support that in western Shark Bay, socially transmitted specializations may have led to the observed genetic structure. The reported genetic structure appears to present an example of cultural hitchhiking of mtDNA haplotypes on socially transmitted foraging strategies, suggesting that, as in humans, genetic structure can be shaped through cultural transmission.
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Osborne, Colin P., and Robert P. Freckleton. "Ecological selection pressures for C 4 photosynthesis in the grasses." Proceedings of the Royal Society B: Biological Sciences 276, no. 1663 (February 25, 2009): 1753–60. http://dx.doi.org/10.1098/rspb.2008.1762.
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Grasses using the C 4 photosynthetic pathway dominate grasslands and savannahs of warm regions, and account for half of the species in this ecologically and economically important plant family. The C 4 pathway increases the potential for high rates of photosynthesis, particularly at high irradiance, and raises water-use efficiency compared with the C 3 type. It is therefore classically viewed as an adaptation to open, arid conditions. Here, we test this adaptive hypothesis using the comparative method, analysing habitat data for 117 genera of grasses, representing 15 C 4 lineages. The evidence from our three complementary analyses is consistent with the hypothesis that evolutionary selection for C 4 photosynthesis requires open environments, but we find an equal likelihood of C 4 evolutionary origins in mesic, arid and saline habitats. However, once the pathway has arisen, evolutionary transitions into arid habitats occur at higher rates in C 4 than C 3 clades. Extant C 4 genera therefore occupy a wider range of drier habitats than their C 3 counterparts because the C 4 pathway represents a pre-adaptation to arid conditions. Our analyses warn against evolutionary inferences based solely upon the high occurrence of extant C 4 species in dry habitats, and provide a novel interpretation of this classic ecological association.
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Tomaŝových, Adam, and Susan M. Kidwell. "Accounting for the effects of biological variability and temporal autocorrelation in assessing the preservation of species abundance." Paleobiology 37, no. 2 (2011): 332–54. http://dx.doi.org/10.1666/09506.1.
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Quantifying the effects of taphonomic processes on species abundances in time-averaged death assemblages (DAs) is pivotal for paleoecological inference. However, fidelity estimates based on conventional “live-dead” comparisons are fundamentally ambiguous: (1) data on living assemblages (LAs) are based on a very short period of sampling and thus do not account for biological variability in the LA, (2) LAs are sampled at the same time as the DA and thus do not necessarily reflect past LAs that contributed to the DA, (3) compositions of LAs and DAs can be autocorrelated owing to shared cohorts, and (4) fidelity estimates are cross-scale estimates because DAs are time-averaged and LAs are not. Some portion of raw (total) live-dead (LD) variation in species composition thus arises from incomplete sampling of LAs and from biological temporal variation among LAs (together = premortem component of LD variation), as contrasted withnewvariation created by interspecific variation in population turnover and preservation rates and by the time-averaging of skeletal input (together = postmortem component of LD variation). To tackle these problems, we introduce a modified test for homogeneity of multivariate dispersions (HMD) in order to (1) account for temporal autocorrelation in composition between LAs and DAs and (2) decompose total LD compositional variation into premortem and postmortem components, and we use simulations to evaluate the contribution of within-habitat time-averaging on the postmortem component. Applying this approach to 31 marine molluscan data sets, each consisting of spatial replicates of LAs and DAs in a single habitat, we find that total LD variation is driven largely by variation among LAs. However, genuinely postmortem processes have significant effects on composition in 25–65% of data sets (depending on the metric) when the effects of temporal autocorrelation are taken into account using HMD. Had we ignored the effects of autocorrelation, the effects of postmortem processes would have been negligible, inflating the similarity between LAs and DAs. Simulations show that within-habitat time-averaging does not increase total LD variation to a large degree—it increases total LD variation mainly via increasing species richness, and decreases total LD variation by reducing dispersion among DAs. The postmortem component of LD variation thus arises from differential turnover and preservation and multi-habitat time-averaging. Moreover, postmortem processes have less effect on the compositions of DAs in habitats characterized by high variability among LAs than they have on DAs in temporally stable habitats, a previously unrecognized first-order factor in estimating postmortem sources of compositional variation in DAs.
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Cecere, Jacopo G., Licia Calabrese, Gerard Rocamora, and Carlo Catoni. "Movement Patterns and Habitat Selection of Wedge-tailed Shearwaters (Puffinus pacificus) Breeding at Aride Island, Seychelles." Waterbirds 36, no. 4 (December 2013): 432–37. http://dx.doi.org/10.1675/063.036.0414.
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Bell, J. R., D. A. Bohan, E. M. Shaw, and G. S. Weyman. "Ballooning dispersal using silk: world fauna, phylogenies, genetics and models." Bulletin of Entomological Research 95, no. 2 (April 2005): 69–114. http://dx.doi.org/10.1079/ber2004350.
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AbstractAerial dispersal using silk (‘ballooning’) has evolved in spiders (Araneae), spider mites (Acari) and in the larvae of moths (Lepidoptera). Since the 17th century, over 500 observations of ballooning behaviours have been published, yet there is an absence of any evolutionary synthesis of these data. In this paper the literature is reviewed, extensively documenting the known world fauna that balloon and the principal behaviours involved. This knowledge is then incorporated into the current evolutionary phylogenies to examine how ballooning might have arisen. Whilst it is possible that ballooning co-evolved with silk and emerged as early as the Devonian (410–355 mya), it is arguably more likely that ballooning evolved in parallel with deciduous trees, herbaceous annuals and grasses in the Cretaceous (135–65 mya). During this period, temporal (e.g. bud burst, chlorophyll thresholds) and spatial (e.g. herbivory, trampling) heterogeneities in habitat structuring predominated and intensified into the Cenozoic (65 mya to the present). It is hypothesized that from the ancestral launch mechanism known as ‘suspended ballooning’, widely used by individuals in plant canopies, ‘tip-toe’ and ‘rearing’ take-off behaviours were strongly selected for as habitats changed. It is contended that ballooning behaviour in all three orders can be described as a mixed Evolutionary Stable Strategy. This comprises individual bet-hedging due to habitat unpredictability, giving an underlying randomness to individual ballooning, with adjustments to the individual ballooning probability being conferred by more predictable habitat changes or colonization strategies. Finally, current methods used to study ballooning, including modelling and genetic research, are illustrated and an indication of future prospects given.
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Branstetter, Michael G., Ana Ješovnik, Jeffrey Sosa-Calvo, Michael W. Lloyd, Brant C. Faircloth, Seán G. Brady, and Ted R. Schultz. "Dry habitats were crucibles of domestication in the evolution of agriculture in ants." Proceedings of the Royal Society B: Biological Sciences 284, no. 1852 (April 12, 2017): 20170095. http://dx.doi.org/10.1098/rspb.2017.0095.
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The evolution of ant agriculture, as practised by the fungus-farming ‘attine’ ants, is thought to have arisen in the wet rainforests of South America about 55–65 Ma. Most subsequent attine agricultural evolution, including the domestication event that produced the ancestor of higher attine cultivars, is likewise hypothesized to have occurred in South American rainforests. The ‘out-of-the-rainforest’ hypothesis, while generally accepted, has never been tested in a phylogenetic context. It also presents a problem for explaining how fungal domestication might have occurred, given that isolation from free-living populations is required. Here, we use phylogenomic data from ultra-conserved element (UCE) loci to reconstruct the evolutionary history of fungus-farming ants, reduce topological uncertainty, and identify the closest non-fungus-growing ant relative. Using the phylogeny we infer the history of attine agricultural systems, habitat preference and biogeography. Our results show that the out-of-the-rainforest hypothesis is correct with regard to the origin of attine ant agriculture; however, contrary to expectation, we find that the transition from lower to higher agriculture is very likely to have occurred in a seasonally dry habitat, inhospitable to the growth of free-living populations of attine fungal cultivars. We suggest that dry habitats favoured the isolation of attine cultivars over the evolutionary time spans necessary for domestication to occur.
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Maíra Leite, ESCORCIO, and DUTRA Elza Maria do Socorro. "Considerações Fenomenológico-existenciais sobre o Habitar no Semiárido Brasileiro." PHENOMENOLOGICAL STUDIES-Revista da Abordagem Gestáltica 24, no. 1 (2018): 57–65. http://dx.doi.org/10.18065/rag.2018v24n1.6.
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Vannimwegen, Ron, and Diane Debinski. "Nest Success of Yellow Warblers in Willow Habitats: The Role of Surface Water and Snakes." UW National Parks Service Research Station Annual Reports 28 (January 1, 2004): 53–57. http://dx.doi.org/10.13001/uwnpsrc.2004.3575.
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Yellow Warblers (Dendroica petechia) are migratory songbirds found in high abundance in the tall willow (Salix boothii) habitats of Grand Teton National Park (GTNP). Willows are found in wet soils with high water tables and varying densities of exposed surface water. Dense surface area of water leads to thick, well foliated, continuous patches of S. boothii, which is the favored nesting habitat of Yellow Warblers. This water, however, also supports the favored prey base of the wandering garter snake (Thamnophis elegans vagrans), which has been known to prey on songbird nest contents when the opportunity arises. We hypothesized that nest territories containing high densities of surface water would also attract garter snakes, and increase the probability of nest failures. We found and monitored 28 Yellow Warbler nests, recorded their locations and fates (success or failure) and measured the density of surface water within each nest territory. We analyzed nest success with the logistic-exposure method coupled with comparisons of models with and without water density as an explanatory variable. Information theoretic model comparison consistently supported models with water density over those without. A significant correlation was found between water density within a nest territory and that nest's daily survival probability. The estimate of this effect was -0.049 (a logistic model parameter) with a standard error of 0.019. Expressed alternatively, each 5-meter per territory increase in waterway density decreases the odds ratio of nest survival by 21%. While water density provides a trade off between nesting habitat and predation pressure, other predation causes and temporal water density variation likely contribute to overall warbler productivity in important ways as well.
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Dick, Jaimie T. A., and Robert W. Elwood. "Effects of Natural Variation in Sex Ratio and Habitat Structure On Mate-Guarding Decisions in Amphipods (Crustacea)." Behaviour 133, no. 13-14 (1996): 985–96. http://dx.doi.org/10.1163/156853996x00567.
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AbstractWe employed field-based studies, with complementary laboratory-based studies, to investigate social and environmental influences on tactical mate-guarding decisions in amphipods (Crustacea). Firstly, we investigated variation in precopulatory mate-guarding duration in Cammarus duebeni celticus in relation to the social structure of natural populations. Variation in population density of up to two orders of magnitude had no effect on precopula duration, whereas guarding durations increased as the sex ratios of the populations became more male biased. That is, males have some ability to assess the probability of other males taking females into precopula and are prepared to guard for longer as this threat of male: male competition increases. A field demonstration of tactical shifts in reproductive behaviour in response to pertinent social conditions is thus provided. Secondly, the 'habitat segregation' hypothesis, which proposes that positive size-assortative pairing in amphipod populations arises due to variation in the use of micro-habitats, was tested in natural field populations and under laboratory conditions in Echinogammarus marinus. This was necessary in order to distinguish any purely environmental determinants of size-assortment from the role of active decisions by males concerning mate choice and male: male competition. The hypothesis was rejected on the grounds that size-assortative pairing arises under both heterogeneous and homogeneous environmental conditions. Further, in both study species, male and female body size were positively correlated with precopula duration. Thus, indirect competition for access to large, fecund females, based on the timing of male entry into precopula, together with direct aggression, provides the explanation for size-assortative pairing in amphipods.
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Becker, Thorsten, and Jonas V. Müller. "Floristic affinities, life-form spectra and habitat preferences of the vegetation of two semi-arid regions in Sahelian West and Southern Africa." Basic and Applied Dryland Research 1, no. 1 (January 1, 2007): 33–50. http://dx.doi.org/10.1127/badr/1/2007/33.
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Ramos, Jaime A. "Characteristics of Foraging Habitats and Chick Food Provisioning by Tropical Roseate Terns." Condor 102, no. 4 (November 1, 2000): 795–803. http://dx.doi.org/10.1093/condor/102.4.795.
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Abstract I studied tropical Roseate Terns (Sterna dougallii) on Aride Island, Seychelles, between 1997–1999. Productivity in 1998 was 0.58 fledglings/breeding pair, and in 1999 no young fledged. Roseate Terns on Aride concentrated their foraging along the coastline exposed to prevailing winds, with flock size over this area being significantly correlated with amount of food offered to chicks. In 1998, Lesser Noddies (Anous tenuirostris) were present in 91% of the Roseate Tern flocks, but in 1999 occurred in only 32%. During the 1998 successful breeding season, Roseate Terns were associated with dense flocks of Lesser Noddies over predatory fish, whereas during the 1999 failure season most Roseate Tern flocks were either monospecific or mixed with Fairy Terns (Gygis alba), and without predatory fish. The mean flock size of Roseate Terns (82 vs. 6 birds) and the rate of foraging attempts (8.3 vs. 2.8 attempts min−1) were significantly greater in association with predatory fish. Mullidae (Parupeneus or Mulloidichthys) were the primary prey taken by Roseate Terns, and alternative sources of food were apparently scarce. The high daily variations in the amount of food brought to chicks, intermediate periods of low food delivery, and an apparent seasonal decline in the amount of food brought to the colony suggest that food is unpredictable on a daily and seasonal basis. Absence of predatory fish may explain complete breeding failures and periods of low food delivery, but the importance of other factors is unknown. Information on the ecology and movement patterns of predatory fish around Aride Island is needed to assist the conservation of the Roseate Terns.
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Benton, Michael J., and Glenn W. Storrs. "Replacement events among tetrapods: expansion or competition?" Paleontological Society Special Publications 6 (1992): 25. http://dx.doi.org/10.1017/s2475262200005852.
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Many macroevolutionary patterns have been explained in the past on the basis of expectations and prejudice rather than quantitative testing. Large-scale ecological replacements have been a prime example, where expectations of progress and competitive advantage have coloured interpretations. Equally, no doubt, others have looked for, and found, evidence for entirely noncompetitive processes to explain major replacements (reviewed, Benton 1987).A partially quantitative approach is presented, based on a study of tetrapod families, marine and nonmarine, through the interval from Devonian to the present day. New data bases of the history of tetrapod diversification have the advantage over older attempts of (1) a fully cladistic phylogeny, and hence monophyletic families; (2) a detailed overview of stratigraphy and improved range data; (3) palaeobiogeographic control; and, (4) definition of ecological categories in terms of mean body size categories, diet, main habitat types (fully marine; partially marine/ coastal; freshwater; aquatic/terrestrial; lowland; upland; arboreal, aerial).The bulk of the diversification of tetrapods is correlated with increases in the ranges both of habitats occupied and of diets (Benton 1990). However, tetrapod families came and went, and a large proportion of the diversification could have been driven by competition and progressive replacement of archaic families by competitively superior ones in ecological relays. In order to test this, the ranges of all tetrapod families were plotted against time and sorted into a variety of habitat, dietary, and palaeogeographic categories.The results do not support a generalised view of competitive ecological relays. The majority of families appear to have arisen within new cells of the matrix, and did not apparently overlap in time with, or follow closely after, any potential competitors. This would be the minimum requirement for a postulate of competition. Only some 5% of cases could be open to a competitive explanation, and these include certain well known examples, such as multituberculates/ rodents, plesiadapiforms/ rodents, ichthyosaurs/ mosasaurs. The present study has narrowed the odds againt large-scale competition as a significant motor of large-scale biotic replacements. Most new taxa of tetrapods appear to have arisen in response to the availability of empty adaptive space.Environmental shifts may also be detected during the course of tetrapod evolution, with expansions offshore to ever more fully aquatic lifestyles among marine tetrapods (because they all arose from terrestrial ancestors!), and with expansions from lowland tropical zones to temperate belts, uplands, and marginal lifestyles (burrowing, climbing, flying) among nonmarine tetrapods.
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Rieger, Anna-Katharina. "Marie-Odile Rousset, Bernard Geyer, Pierre-Louis Gatier, Nazir Awad (Edd.): Habitat et Environnement. Prospections dans les marges arides de la Syrie du Nord." Gnomon 92, no. 2 (2020): 149–55. http://dx.doi.org/10.17104/0017-1417-2020-2-149.
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Esin, Evgeny V., Grigorii N. Markevich, and Michail Yu Pichugin. "Juvenile divergence in adaptive traits among seven sympatric fish ecomorphs arises before moving to different lacustrine habitats." Journal of Evolutionary Biology 31, no. 7 (May 5, 2018): 1018–34. http://dx.doi.org/10.1111/jeb.13283.
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Sahoo, Debgopal, Guruprasad Samanta, and Manuel De la Sen. "Impact of Fear and Habitat Complexity in a Predator-Prey System with Two Different Shaped Functional Responses: A Comparative Study." Discrete Dynamics in Nature and Society 2021 (September 10, 2021): 1–22. http://dx.doi.org/10.1155/2021/6427864.
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Habitat complexity or the structural complexity of habitat reduces the available space for interacting species, and subsequently, the encounter rate between the prey and predator is decreased significantly. Different experimental shreds of evidence validate that the presence of the predator strongly affects the physiological behaviour of prey individuals and dramatically reduces their reproduction rate. In this study, we investigate the interplay between the level of fear and the degree of habitat complexity in a predator-prey model with two different shaped functional responses. We, therefore, develop the functional response using the timescale separation method, and the shape of the resulting functional response depends upon the monotonous property of catch rate, g N where N is the prey biomass. Whenever g N increases strictly, a saturating functional response occurs, but for nonmonotonic g N , a dome-shaped functional response arises. For saturating case, it has been revealed that both prey and predator biomass may oscillate for lower levels of fear and a lower degree of habitat complexity. To stabilize this oscillatory behaviour to a coexistence state, we have to adequately increase the level of fear or degree of habitat complexity. However, for dome-shaped case, more complicated dynamics are observed. In this case, coexistence steady state, if exists, may be locally asymptotically stable for a lower degree of habitat complexity, but for intermediate values, the system is capable of producing multiple coexistence steady states with a bistable phenomenon between predator-free steady state and a coexistence steady state. Moreover, if the level of fear is sufficiently low, the system may experience a supercritical or/and subcritical Hopf bifurcation. In the dynamics of parametric disturbance for the degree of habitat complexity parameter, dome-shaped functional response predicts that disturbance may trap the system into a nearest attractor (either a large amplitude stable limit cycle or predator-free steady state); this can be overcome only by a larger alteration, or sometimes it is impossible to overcome (hysteresis phenomena), whereas the saturating-shaped functional response predicts a system resilience. For both the functional responses, a higher degree of habitat complexity always increases the extinction possibility of the predator, and no level of fear can compensate this biodiversity loss.
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Blanchard, Pierrick, Christine Lauzeral, Simon Chamaillé-Jammes, Nigel G. Yoccoz, and Dominique Pontier. "Analyzing the proximity to cover in a landscape of fear: a new approach applied to fine-scale habitat use by rabbits facing feral cat predation on Kerguelen archipelago." PeerJ 4 (March 7, 2016): e1769. http://dx.doi.org/10.7717/peerj.1769.
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Although proximity to cover has been routinely considered as an explanatory variable in studies investigating prey behavioral adjustments to predation pressure, the way it shapes risk perception still remains equivocal. This paradox arises from both the ambivalent nature of cover as potentially both obstructive and protective, making its impact on risk perception complex and context-dependent, and from the choice of the proxy used to measure proximity to cover in the field, which leads to an incomplete picture of the landscape of fear experienced by the prey. Here, we study a simple predator-prey-habitat system, i.e., rabbitsOryctolagus cuniculusfacing feral catFelis catuspredation on Kerguelen archipelago. We assess how cover shapes risk perception in prey and develop an easily implementable field method to improve the estimation of proximity to cover. In contrast to protocols considering the “distance to nearest cover”, we focus on the overall “area to cover”. We show that fine-scale habitat use by rabbits is clearly related to our measure, in accordance with our hypothesis of higher risk in patches with smaller area to cover in this predator-prey-habitat system. In contrast, classical measures of proximity to cover are not retained in the best predictive models of habitat use. The use of this new approach, together with a more in-depth consideration of contrasting properties of cover, could help to better understand the role of this complex yet decisive parameter for predator-prey ecology.
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Nyamwamu, Ronald Orare, and Justus Moturi Ombati. "Effectiveness of Agricultural Extension Wildlife Mitigation Strategies on Human-Wildlife Conflict Among Small-Scale Maize Farmers in Laikipia County, Kenya." Journal of International Agricultural and Extension Education 25, no. 1 (May 15, 2018): 51–59. http://dx.doi.org/10.5191/jiaee.2018.25105.
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Agriculture is critical in the achievement of food security, employment of creation opportunities, steering economic growth, and also a source of raw materials for agricultural industries in many Sub-Saharan countries. However, farmers face various challenges which negatively affect farm productivity and production. Human-wildlife conflict is one of the most pressing challenges that smallholder maize farmers experience in some parts of Kenya. It arises from either people’s encroachment on wildlife habitats or the movement of wildlife from their natural habitat into neighboring farmland. Small-scale farmers use various agricultural extension strategies to mitigate the conflict. However, the effectiveness of the agricultural extension mitigation strategies adopted by smallholder maize farmers in Laikipia County had not been investigated and information on the same was inadequate and poorly documented. This study sought to determine the effectiveness of the agricultural extension wildlife conflict mitigation strategies adopted by smallholder maize farmers in Laikipia County. Whereas a document review guide was used to collect secondary data, semi-structured questionnaires were used to collect primary data from maize farmers and extension agents. Descriptive statistics were used to analyze primary data. It was established that crop damage was very severe, even up to 70% per cropping season although farmers used mitigation strategies such growing of unpalatable plants, live fences, hairy crops, and digging trenches. This study concluded that the Agricultural Extension Mitigation Strategies used were not effective. It was recommended concerted efforts between stakeholders in the conflict to realize the benefits of synergies so as to stem crop damage and give small-scale farmers a chance to be food secure.
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Zivanovic-Milic, Tijana, and Sinisa Trkulja. "Serbia and the Danube area in the light of the new urban agenda." Spatium, no. 38 (2017): 51–58. http://dx.doi.org/10.2298/spat1738051z.
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A new global framework to guide urban development and housing policy in the next twenty years - the New Urban Agenda was adopted at the end of the Habitat III Conference held in Quito, Ecuador. This time, the Agenda was tailored and adopted to the requirements of the Sustainable Development Goals and particularly to the requirements of Goal 11 - Make cities inclusive, safe, resilient and sustainable, established in 2015. The paper outlines the basic facts indicating the complexity of Agenda-making and the entire Habitat III process. It also points to the first controversies that have arisen around and after the conference in Quito and examines the importance attached, and the one that the Agenda might have in the future in the Danube countries, especially in Serbia, taking into account demographic trends, diversity in the level of the existing quality of urban life and challenges to be met.
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Dunbar, R. I. M., Padraig MacCarron, and Cole Robertson. "Trade-off between fertility and predation risk drives a geometric sequence in the pattern of group sizes in baboons." Biology Letters 14, no. 3 (March 2018): 20170700. http://dx.doi.org/10.1098/rsbl.2017.0700.
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Group-living offers both benefits (protection against predators, access to resources) and costs (increased ecological competition, the impact of group size on fertility). Here, we use cluster analysis to detect natural patternings in a comprehensive sample of baboon groups, and identify a geometric sequence with peaks at approximately 20, 40, 80 and 160. We suggest (i) that these form a set of demographic oscillators that set habitat-specific limits to group size and (ii) that the oscillator arises from a trade-off between female fertility and predation risk.
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El-Amier, Yasser A., Ahmed El-Zeiny, El-Sayed F. El-Halawany, Ashraf Elsayed, Mohamed A. El-Esawi, Ahmed Noureldeen, Hadeer Darwish, Amal Al-Barty, and Shrouk A. Elagami. "Environmental and Stress Analysis of Wild Plant Habitat in River Nile Region of Dakahlia Governorate on Basis of Geospatial Techniques." Sustainability 13, no. 11 (June 3, 2021): 6377. http://dx.doi.org/10.3390/su13116377.
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Spatiotemporal environmental changes lead to disturbances in wild plant habitats, particularly in regions characterized by changeable land use and cover. The present study aims to characterize wild plant habitats in the River Nile region of Dakahlia Governorate using a multidisciplinary approach, incorporating remote sensing, GIS and sampling analyses. Twenty-four stands representing the wild plant habitats in the River Nile region were geographically identified, sampled and analyzed. Water and soil samples were investigated for physical and chemical characteristics. Two calibrated multispectral Landsat images dated 1999 and 2019 were processed to produce LULC, NDSI, NDMI and NDSI to characterize wild plan habitats. The floristic composition showed the presence of 64 species belonging to 53 genera and 28 families. Ecologically, the recorded plant species in the present work can be classified into four main categories, which are separated into three communities according to the TWINSPAN classification. Results showed that the annual loss of agricultural lands (3.98 km2) is closely relevant to the annual expansion of urban areas (4.24 km2). Although the uncontrolled urban sprawl caused loss of agricultural lands, it leads to the expansion of wild plant habitats, represented mainly by the sparse class and partially by the moderately dense class as obtained from NDVI. The increase in mean values of the moisture (NDMI) from 0.034 in 1999 to 0.64 in 2019 may have arisen from the increase in total areas of wild plant habitats during the investigated period (1999–2019). This might increase the suitability of conditions for wild habitats which induces the proliferation of natural plants.
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Newsome, A. E., P. C. Catling, B. D. Cooke, and R. Smyth. "Two ecological universes separated by the Dingo Barrier Fence in semi-arid Australia: interactions between landscapes, herbivory and carnivory, with and without dingoes." Rangeland Journal 23, no. 1 (2001): 71. http://dx.doi.org/10.1071/rj01015.
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This paper challenges conclusions of Caughley et al. (1980) that the abundance of red kangaroos (Macropus rufus) in western New South Wales is solely due to lack of dingoes (Canis lupus dingo), and vice versa for neighbouring South Australia. A Dingo Barrier Fence divides the two different ecological systems, which have sheep in New South Wales and cattle in South Australia. This paper re-examines in particular whether there is an environmental gradient across the Fence that was dismissed by Caughley et al. This paper concludes to the contrary, that there is a strong environmental gradient. Our aerial surveys demonstrate significantly that habitats favouring red kangaroos are prevalent in New South Wales today, but are very scarce or absent in South Australian landscapes. Aerial surveys were used in both studies, but designs differed. Caughley et al. flew at right angles across the Fence on paths 28 km apart. Flights would have crossed the south-westerly streamlines rarely. Our flight lanes followed streamlines looking for floodouts, the favourite habitat of red kangaroos. Return lanes went between streamlines sampling other habitats. Counts of red kangaroos seen were made every 1.75 km, with the specific habitat also identified. Three extra factors are invoked in our study. One is that the low annual rainfalls translate into intrinsically low survival rates of pouch-young of red kangaroos, contrary to their abundance in New South Wales today. The other two are related to that current abundance also. There is now evidence for greatly increased run-off of rainfall from catchments onto the open plains in New South Wales. Also present is a very large shallow basin lying between catchments and the Dingo Barrier Fence. Streamlines enter it but none flow past its western rim. The above conclusions were confirmed during subsequent ground surveys over three years. Of eleven species of medium and large vertebrates seen in New South Wales, five were absent in South Australia. Three were kangaroos, and the others were feral pigs and goats. Emus are more abundant in New South Wales also. All of those species would be targets for dingoes, especially as alternate prey to rabbits that generate huge eruptions every decade or so. Red foxes (Vulpes vulpes) were in lower abundance in South Australia with dingoes present, as expected with meso-predator interactions. Feral cats (Felis catus) were in similar numbers on both sides of the Fence for unknown reasons. Competition between rabbits (Oryctolagus cuniculus) and sheep for food in New South Wales was shown to significantly reduce rabbit numbers in drought. That rabbits are perennially in lower densities there than in South Australia may be due to the higher densities of foxes than in South Australia. Historically, red kangaroos were rare in the region in the mid-1800s. Their abundance has arisen since European occupation. Thc species was rare on those open plains, and permanent water was scarce. Rabbit Haemorrhagic Disease reached the study-area in 1995. Its impact reduced rabbit populations to a rarity that prevails today on both sides of the Dingo Fence. Predation from dingoes, foxes and feral cats may assist continuance of low numbers of rabbits. Pastures, seedling trees and livestock will benefit, as will the kangaroos.
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Mercer, John P., R. Colin A. Bannister, Gro I. van der Meeren, Valerie Debuse, David Mazzoni, Steve Lovewell, Ronan Browne, Adrian Linnane, and Brendan Ball. "An overview of the LEAR (Lobster Ecology and Recruitment) project: results of field and experimental studies on the juvenile ecology of Homarus gammarus in cobble." Marine and Freshwater Research 52, no. 8 (2001): 1291. http://dx.doi.org/10.1071/mf01216.
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Field and experimental studies were undertaken in four European countries on clawed lobster (Homarus gammarus) ecology and recruitment. The aims were to assess: (a) abundance of early benthic phase (EBP) lobsters and other benthic species at cobble sites, (b) the effect of these species on EBP growth and survival, and (c) influence of these factors on recruitment and/or viability of restocking. Suction sampling of cobble sites revealed a wide diversity and abundance of potential competitors but no EBP lobsters. Hatchery-produced EBPs were therefore used for small-scale mesocosm experiments. In nature, predation on EBP was rapid without shelter, whereas in-vitro mortality, growth, and behaviour experiments showed that cover potentially increases survival. Scarcity per se may not completely explain the apparently absence of EBP, given that not a single EBP lobster was located either during this study or during any other of the extensive benthic investigations. The present paper discusses the implications of their apparent absence and whether it arises because EBPs are very scarce, cannot be captured by suction sampling, are not within lobster habitat, or occupy a specialized niche within adult habitat outside the range of current sampling methods.
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Maezo, Maria José, Henri Fournier, and Beatrix E. Beisner. "Potential and realized interactions between two aquatic invasive species: Eurasian watermilfoil (Myriophyllum spicatum) and rusty crayfish (Orconectes rusticus)." Canadian Journal of Fisheries and Aquatic Sciences 67, no. 4 (April 2010): 684–700. http://dx.doi.org/10.1139/f10-016.
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With multiple invasions, the potential arises for interactions between invasives inhibiting or promoting spread. Our goal was to investigate the interaction between two invasives, Eurasian watermilfoil ( Myriophyllum spicatum ) and rusty crayfish ( Orconectes rusticus ), which co-occur in several lakes in western Quebec, Canada, and to determine their overlap with littoral fish communities. Crayfish potentially aid milfoil dispersal by fragmentation or, alternatively, inhibit its proliferation through destruction and direct consumption. With a mesocosm experiment, we quantified milfoil fragment production versus biomass reduction by crayfish. More fragments were produced at medium to high crayfish densities, with a significant reduction of milfoil only at the highest densities, demonstrating the potential for both positive and negative interactions. Second, we determined the habitat preferences of each species by conducting a survey in the same lake. There was little overlap in the species’ distributions, with each preferring different habitat features, indicating either a low probability of interaction or that interaction occurred historically, resulting in a contemporary exclusion pattern. While our experiment showed a potential for significant interaction, the low natural co-occurrence of these species suggests that they do not currently influence each other or that they previously excluded each other.
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Sanger, Thomas J., Liam J. Revell, Jeremy J. Gibson-Brown, and Jonathan B. Losos. "Repeated modification of early limb morphogenesis programmes underlies the convergence of relative limb length in Anolis lizards." Proceedings of the Royal Society B: Biological Sciences 279, no. 1729 (August 17, 2011): 739–48. http://dx.doi.org/10.1098/rspb.2011.0840.
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The independent evolution of similar morphologies has long been a subject of considerable interest to biologists. Does phenotypic convergence reflect the primacy of natural selection, or does development set the course of evolution by channelling variation in certain directions? Here, we examine the ontogenetic origins of relative limb length variation among Anolis lizard habitat specialists to address whether convergent phenotypes have arisen through convergent developmental trajectories. Despite the numerous developmental processes that could potentially contribute to variation in adult limb length, our analyses reveal that, in Anolis lizards, such variation is repeatedly the result of changes occurring very early in development, prior to formation of the cartilaginous long bone anlagen.
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Horáčková, Jitka, Štěpánka Podroužková, and Lucie Juřičková. "River Floodplains as Habitat and Bio-Corridors for Distribution of Land Snails: Their Past and Present." Journal of Landscape Ecology 8, no. 3 (December 1, 2015): 23–39. http://dx.doi.org/10.1515/jlecol-2015-0012.
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Abstract River floodplains of Czech rivers serve as refugia to woodland or hydrophilous gastropods, in current intensively agriculturally utilised, urbanised and largely fragmented landscape. This habitat often form one of the last refuge and replace the natural habitat of these species. River floodplains also represent linear bio-corridors in landscape and allow gastropods to spread through the landscape in both directions, up and down the stream. We showed based on available fossil mollusc successions that development of the floodplain mollusc fauna took place quite different way in various river floodplains, depending on their specifics and geographical location, because especially the ones situated in the chernozem area of the Czech Republic had very different history in comparison with those in higher altitudes. The species richness and composition of recent floodplain malacofauna arises from historical development of particular area/site and depends also on environmental factors such as an elevation, humidity gradient, vegetation type and its biomass, light conditions of the site and soil reaction. Recently, the invasive plants represent a serious problem for current floodplain ecosystems; species richness and abundances of terrestrial mollusc floodplain assemblages are changing due to their effect. The impact on gastropods is species-specific and was described for the following species: Impatiens glandulifera, Fallopia japonica subsp. japonica, F. sachalinensis, F. ×bohemica.
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Peacock, E., A. E. Derocher, G. W. Thiemann, and I. Stirling. "Conservation and management of Canada’s polar bears (Ursus maritimus) in a changing Arctic1This review is part of the virtual symposium “Flagship Species – Flagship Problems” that deals with ecology, biodiversity and management issues, and climate impacts on species at risk and of Canadian importance, including the polar bear (Ursus maritimus), Atlantic cod (Gadus morhua), Piping Plover (Charadrius melodus), and caribou (Rangifer tarandus)." Canadian Journal of Zoology 89, no. 5 (May 2011): 371–85. http://dx.doi.org/10.1139/z11-021.
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Canada has an important responsibility for the research, conservation, and management of polar bears ( Ursus maritimus Phipps, 1774) because the majority of polar bears in the world occur within the nation’s borders. Two fundamental and recent changes for polar bears and their conservation have arisen: (1) the ongoing and projected further decline of sea-ice habitat as a result of climate change and (2) the implementation of aboriginal land claims and treaties in Canada’s North. Science has documented empirical links between productivity of polar bear population and sea-ice change. Predictive modeling based on these data has forecast significant declines in polar bear abundance and distribution of polar bears. With the signing of northern land claims and treaties, polar bear management in Canada has integrated local aboriginal participation, values, and knowledge. The interaction of scientific and local perspectives on polar bears as they relate to harvest, climate change, and declining habitat has recently caused controversy. Some conservation, management, and research decisions have been contentious because of gaps in scientific knowledge and the polarization and politicization of the roles of the various stakeholders. With these ecological and governance transitions, there is a need to re-focus and re-direct polar bear conservation in Canada.
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Liebig, Katrin, Mathias Boelke, Domenic Grund, Sabine Schicht, Malena Bestehorn-Willmann, Lidia Chitimia-Dobler, Gerhard Dobler, Klaus Jung, and Stefanie C. Becker. "The Stable Matching Problem in TBEV Enzootic Circulation: How Important Is the Perfect Tick-Virus Match?" Microorganisms 9, no. 1 (January 19, 2021): 196. http://dx.doi.org/10.3390/microorganisms9010196.
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Tick-borne encephalitis virus (TBEV), like other arthropod-transmitted viruses, depends on specific vectors to complete its enzootic cycle. It has been long known that Ixodes ricinus ticks constitute the main vector for TBEV in Europe. In contrast to the wide distribution of the TBEV vector, the occurrence of TBEV transmission is focal and often restricted to a small parcel of land, whereas surrounding areas with seemingly similar habitat parameters are free of TBEV. Thus, the question arises which factors shape this focal distribution of TBEV in the natural habitat. To shed light on factors driving TBEV-focus formation, we used tick populations from two TBEV-foci in Lower Saxony and two TBEV-foci from Bavaria with their respective virus isolates as a showcase to analyze the impact of specific virus isolate-tick population relationships. Using artificial blood feeding and field-collected nymphal ticks as experimental means, our investigation showed that the probability of getting infected with the synonymous TBEV isolate as compared to the nonsynonymous TBEV isolate was elevated but significantly higher only in one of the four TBEV foci. More obviously, median viral RNA copy numbers were significantly higher in the synonymous virus–tick population pairings. These findings may present a hint for a coevolutionary adaptation of virus and tick populations.
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Fjeldså, J. "The avifauna of thePolylepiswoodlands of the Andean highlands: the efficiency of basing conservation priorities on patterns of endemism." Bird Conservation International 3, no. 1 (March 1993): 37–55. http://dx.doi.org/10.1017/s0959270900000770.
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SummaryThe Andean páramo and puna zones may once have been densely dotted by woodlands, mainly ofPolylepis, but human impact has now led to a highly disjunct distribution of this habitat. Because of the habitat fragmentation, many specialized woodland birds now show relictual distributions. Speciations to thePolylepiszone took place in Peru and Bolivia during cold/arid climatic periods, asPolylepis-dominated woodland refuges were isolated away from the humid cis-Andean zone and the pre-Andean scrub-forest in Bolivia. An efficient protection of biodiversity in a minimum of well-managed areas could be achieved, if efforts were concentrated in highlands near the proposed Pleistocene woodland refuges: 55% of all endemic and 67% of all threatened and near-threatened landbirds of the high Andean zone of Peru and Bolivia were recorded within three 10 x 10 km study plots near Cochabamba in Bolivia and east of Abancay and on the east slope of Cordillera Blanca in Peru. The biological basis for the efficiency of this approach is discussed.Los páramos y punas Andinas pueden haber estado densamente poblados de bosques, principalmente dePolylepis, pero el impacto humano ha causado una distribución muy esparcida de este habitat. Debido a la fragmentatión del habitat, muchos pájaros especializados al bosque, ahora muestran distribuciones rudimentales. La diferenciación de las espeties en la zona dePolylepisse dió en Perú y Bolivia durante períodos climáticos fríos/aridos, al igual que los refúgios de bosques dominados porPolylepisfueron aislados de la zona húmeda cis-Andina y de la zone chaqueña en Bolivia. Se podría lograr una protección efitiente de la biodiversidad en un mínimo de áreas bien manejadas, si se concentrasen los esfuerzos en las sierras cerca de los refúgios propuestos de bosque Pleistocenico. Así es, que un 55% de los pájaros endémicos y 67% de todos los especies en peligro de extintión de la zona alto-Andina de Perú y Bolivia fueron registrados dentro de tres áreas de estudio de 10 × 10 km, cerca de Cochabamba en Bolivia, y al sureste de Abancay y en la vertiente oriental de la Cordillera Blanca en Perú. El artículo diserta los processos básicos.
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Witucki Brown, Janet, Shu-li Chen, Linda Mefford, Allie Brown, Bonnie Callen, and Polly McArthur. "Becoming an Older Volunteer: A Grounded Theory Study." Nursing Research and Practice 2011 (2011): 1–8. http://dx.doi.org/10.1155/2011/361250.
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This Grounded Theory study describes the process by which older persons “become” volunteers. Forty interviews of older persons who volunteered for Habitat for Humanity were subjected to secondary content analysis to uncover the process of “becoming” a volunteer. “Helping out” (core category) for older volunteers occurs within the context of “continuity”, “commitment” and “connection” which provide motivation for volunteering. When a need arises, older volunteers “help out” physically and financially as health and resources permit. Benefits described as “blessings” of volunteering become motivators for future volunteering. Findings suggest that older volunteering is a developmental process and learned behavior which should be fostered in older persons by personally inviting them to volunteer. Intergenerational volunteering projects will allow older persons to pass on knowledge and skills and provide positive role modeling for younger volunteers.
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Seymour, Mona. "“Support Your Local Invasive Species”: Animal Protection Rhetoric and Nonnative Species." Society & Animals 21, no. 1 (2013): 54–73. http://dx.doi.org/10.1163/15685306-12341269.
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Abstract This article explores protection efforts that have arisen in the New York City metropolitan area around the monk parakeet, a nonnative bird that has achieved a broad distribution outside its native habitat range. In some urban regions in which populations are established, controversy has developed around the parakeets’ use of utility infrastructure and potential impacts on native species and agricultural crops. This case provides an opportunity to explore animal protection rhetoric about nonnative species, an understudied topic, considering the great extent to which species have become established in ecosystems outside their natural ranges and the persistence of public affinity for nonnative plants and wildlife. This article identifies four major frames through which advocates have delivered the birds to public and legal audiences and considers how they have mobilized and handled notions of “nonnative-ness” in their advocacy work.
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Burgstaller, Wolfgang. "Thermodynamic boundary conditions suggest that a passive transport step suffices for citrate excretion in Aspergillus and Penicillium." Microbiology 152, no. 3 (March 1, 2006): 887–93. http://dx.doi.org/10.1099/mic.0.28454-0.
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Excretion of organic acids, e.g. citrate, by anamorphic fungi is a frequent phenomenon in natural habitats and in laboratory cultures. In biotechnological processes for citrate production with Aspergillus niger extracellular citrate concentrations up to 1 mol l−1 are achieved. Intracellular citrate concentrations are in the millimolar range. Therefore the question arises whether citrate excretion depends on active transport. In this article thermodynamic calculations are presented for citrate excretion by A. niger at an extracellular pH of 3 and by Penicillium simplicissimum at an extracellular pH of 7. From the results of these calculations it is concluded that in both cases a passive transport step suffices for citrate excretion.
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Biewener, Andrew, and Thomas Daniel. "A moving topic: control and dynamics of animal locomotion." Biology Letters 6, no. 3 (April 21, 2010): 387–88. http://dx.doi.org/10.1098/rsbl.2010.0294.
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Animal locomotion arises from complex interactions among sensory systems, processing of sensory information into patterns of motor output, the musculo-skeletal dynamics that follow motor stimulation, and the interaction of appendages and body parts with the environment. These processes conspire to produce motions and forces that permit stunning manoeuvres with important ecological and evolutionary consequences. Thus, the habitats that animals may exploit, their ability to escape predators or attack prey, their capacity to manoeuvre and turn, or the use of their available energy all depend upon the processes that determine locomotion. Here, we summarize a series of 10 papers focused on this integrative research topic.
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Appel, Markus, and Gero von Daniels. "SPAs and SACs in Conversion Areas?" Journal for European Environmental & Planning Law 4, no. 2 (2007): 97–109. http://dx.doi.org/10.1163/187601007x00109.
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AbstractAt times, European nature conservation efforts seem to create obstacles in their own path. One striking example for this is at present coming into focus in East Germany, where the huge crater-like holes remaining from the massive open cast lignite mining activities in the former GDR are to be recultivated and rehabilitated. However, birds have nonetheless already begun to settle and habitats have formed in some parts of the areas in question, so that the designation of the areas as 'Special Protection Areas' (SPAs) and 'Special Areas of Conservation' (SACs) within the meaning of the Birds and Habitats Directives seems indicated. On the other hand, it would be very difficult, if not impossible, to realise the intended recultivation and rehabilitation measures in SPAs or SACs. The same dilemma may be encountered in other regions of Europe, especially in Eastern Europe, where former mining, industrial or military sites or similar areas are being subjected to a sea change. In this connection, the question arises of whether such areas in the process of conversion are eligible to be considered as SPAs and SACs at all.
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Ishikawa, Asano, Yoel E. Stuart, Daniel I. Bolnick, and Jun Kitano. "Copy number variation of a fatty acid desaturase gene Fads2 associated with ecological divergence in freshwater stickleback populations." Biology Letters 17, no. 8 (August 2021): 20210204. http://dx.doi.org/10.1098/rsbl.2021.0204.
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Fitness of aquatic animals can be limited by the scarcity of nutrients such as long-chain polyunsaturated fatty acids, especially docosahexaenoic acid (DHA). DHA availability from diet varies among aquatic habitats, imposing different selective pressures on resident animals to optimize DHA acquisition and synthesis. For example, DHA is generally poor in freshwater ecosystems compared to marine ecosystems. Our previous work revealed that, relative to marine fishes, several freshwater fishes evolved higher copy numbers of the fatty acid desaturase2 ( Fads2 ) gene, which encodes essential enzymes for DHA biosynthesis, likely compensating for the limited availability of DHA in freshwater. Here, we demonstrate that Fads2 copy number also varies between freshwater sticklebacks inhabiting lakes and streams with stream fish having higher Fads2 copy number. Additionally, populations with benthic-like morphology possessed higher Fads2 copy number than those with planktivore-like morphology. This may be because benthic-like fish mainly feed on DHA-deficient prey such as macroinvertebrates whereas planktivore-like fish forage more regularly on DHA-rich prey, like copepods. Our results suggest that Fads2 copy number variation arises from ecological divergence not only between organisms exploiting marine and freshwater habitats but also between freshwater organisms exploiting divergent resources.
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Campbell, Stuart J., Joshua E. Cinner, Rizya L. Ardiwijaya, Shinta Pardede, Tasrif Kartawijaya, Ahmad Mukmunin, Yudi Herdiana, Andrew S. Hoey, Morgan S. Pratchett, and Andrew H. Baird. "Avoiding conflicts and protecting coral reefs: customary management benefits marine habitats and fish biomass." Oryx 46, no. 4 (October 2012): 486–94. http://dx.doi.org/10.1017/s0030605312000348.
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AbstractOne of the major goals of coral reef conservation is to determine the most effective means of managing marine resources in regions where economic conditions often limit the options available. For example, no-take fishing areas can be impractical in regions where people rely heavily on reef fish for food. In this study we test whether coral reef health differed among areas with varying management practices and socio-economic conditions on Pulau Weh in the Indonesian province of Aceh. Our results show that gear restrictions, in particular prohibiting the use of nets, were successful in minimizing habitat degradation and maintaining fish biomass despite ongoing access to the fishery. Reef fish biomass and hard-coral cover were two- to eight-fold higher at sites where fishing nets were prohibited. The guiding principle of the local customary management system, Panglima Laot, is to reduce conflict among community members over access to marine resources. Consequently, conservation benefits in Aceh have arisen from a customary system that lacks a specific environmental ethic or the means for strong resource-based management. Panglima Laot includes many of the features of successful institutions, such as clearly defined membership rights and the opportunity for resource users to be involved in making, enforcing and changing the rules. Such mechanisms to reduce conflict are the key to the success of marine resource management, particularly in settings that lack resources for enforcement.
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Nehm, Ross H., and Dana H. Geary. "A gradual morphologic transition during a rapid speciation event in marginellid gastropods (Neogene: Dominican Republic)." Journal of Paleontology 68, no. 4 (July 1994): 787–95. http://dx.doi.org/10.1017/s0022336000026226.
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We document a speciation event between two species of Prunum (Marginellidae: Gastropoda) in Pliocene strata of the northern Dominican Republic. The ancestral species, P. coniforme, is widely distributed in the Mio-Pliocene of the Dominican Republic and Jamaica, and has a range of at least 11 m.y. The descendant species, P. christineladdae, is endemic to the northern Dominican Republic. The ancestral species persists after its descendant arises. The transition between species is marked by stratigraphic and morphologic intermediates, and occurs during an interval estimated to be between 73,000 and 275,000 years (representing 0.6-2.5 percent of the duration of the ancestral species). Although the transition takes more than a geologic instant, the overall pattern of morphologic change is best described by the model of punctuated equilibrium. The change between species apparently involved a habitat shift into deeper water, and occurred during accelerated deepening. All of the Neogene Dominican species of Prunum appear to have had depth-defined ranges.
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Anderson, James L., Frank Asche, and Taryn Garlock. "Economics of Aquaculture Policy and Regulation." Annual Review of Resource Economics 11, no. 1 (October 5, 2019): 101–23. http://dx.doi.org/10.1146/annurev-resource-100518-093750.
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Since the Blue Revolution began in the late 1960s, global aquaculture production has grown rapidly. Aquaculture now accounts for over half of the world's fish for direct human consumption and is expected to approach two-thirds by 2030. With aquaculture's growth, a number of high-profile concerns have arisen, including pollution, feeding practices, disease management and antibiotic use, habitat use, non-native species, food safety, fraud, animal welfare, impacts on traditional wild fisheries, access to water and space, market competition, and genetics. Managing these concerns requires thoughtful and well-designed policies and regulations. This manuscript reviews the contributions natural resource economics has made to evaluating aquaculture policy and regulation. Despite their valuable contributions, however, economists have been largely underrepresented in the debate. The primary influencers of aquaculture policies and regulations have been traditional fisheries managers, environmental groups, and natural scientists. We identify many important areas that should be more thoroughly addressed by economists.
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Milsom, William K. "Mechanisms of ventilation in lower vertebrates: adaptations to respiratory and nonrespiratory constraints." Canadian Journal of Zoology 67, no. 12 (December 1, 1989): 2943–55. http://dx.doi.org/10.1139/z89-417.
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The design of vertebrate respiratory systems has been subject to two major sets of constraints. The first is the need to satisfy the primary function of the respiratory surface as an organ of gas exchange. These constraints include the need to reduce the diffusion gradient between air and blood while providing adequate ventilation and perfusion of the exchange surface. The second set of constraints arises from the need to satisfy other physiological, environmental, and behavioral demands. The constraints imposed by the low oxygen content and high density of water as a respiratory medium, the rigid shell of turtles, and the long thin body of snakes, as well as the life-style and habitat of diving animals, are all used to illustrate the unique features of several experiments in the design and performance of respiratory pumps. It is shown, however, that despite the tremendous diversity that exists among species, all mechanisms allow ventilation to be powered by surprisingly similar changes in pulmonary pressure.
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Francis, R., and D. J. Read. "Mutualism and antagonism in the mycorrhizal symbiosis, with special reference to impacts on plant community structure." Canadian Journal of Botany 73, S1 (December 31, 1995): 1301–9. http://dx.doi.org/10.1139/b95-391.
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Examination of the roots of land plants has revealed the occurrence of mycorrhiza in the majority of species, over 70% of which are hosts to zygomycetous fungi that form vesicular–arbuscular (VA) associations. On the basis of experiments with a small number of host species showing enhancement of growth following colonization, it is widely assumed that wherever mycorrhizas are observed, the symbiosis is of the mutualistic type. The value of definitions based on structural rather than functional attributes is here brought into question by experiments simulating the ecologically realistic circumstance in which seeds germinate in soil in the presence or absence of established VA mycelium. These reveal a spectrum of fungal impacts in which some species respond mutualistically, while others, putative hosts or nonhosts, are antagonised, showing reduction of yield and survivorship and, hence, a loss of fitness relative to plants grown without VA fungi. Antagonised species normally grow in disturbed, open habitats and fail to establish in closed communities. It is hypothesised that their turf incompatibility arises from a sensitivity to interference by VA fungi, which consigns them to ruderal habitats. Mycorrhizal fungi, thus, play a role in defining the ecological niches occupied by plants and in determining of plant community composition. Key words: mycorrhiza, vesicular–arbuscular, mutualism, symbiosis, antagonism, plant community.
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Evans, Roger M., and Clive V. J. Welham. "Aggregative mechanisms and behavior in ring-billed gulls departing from a colony." Canadian Journal of Zoology 63, no. 12 (December 1, 1985): 2767–74. http://dx.doi.org/10.1139/z85-412.
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Departures of ring-billed gulls (Larus delawarensis) from a breeding colony were significantly clumped in time and space. Mean departure directions did not correlate among successive days, but were highly correlated with wind direction. Most gulls circling about the colony did not depart. Gulls that did depart typically flew directly away from the colony and approximately half emitted distinctive "contact" calls. Significantly more gulls departed when others were soaring on nearby thermals than at other comparable times. Playback experiments showed that contact calls and calls from thermal flocks attracted other gulls. A causal model of flock formation, derived from the assumption that temporal clumping arises from social facilitation superimposed upon random departure times, was supported by (i) random fly-up times by nondeparting gulls, (ii) demonstrated attractiveness of contact calls, (iii) characteristically direct flight paths of departing gulls, and (iv) by simulations of departing gulls. Social attraction, temporal and spatial grouping, wind, and visual contact between successively departing birds all appear to facilitate aggregation within localized regions of the habitat.
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Griffin, John N., and Brian R. Silliman. "Predator diversity stabilizes and strengthens trophic control of a keystone grazer." Biology Letters 7, no. 1 (August 25, 2010): 79–82. http://dx.doi.org/10.1098/rsbl.2010.0626.
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Despite the global vulnerability of predators to extinction, and the critical functional role they play in many ecosystems, there have been few realistic tests of the consequences of predator species deletion (conversely, predator diversity) in natural ecosystems. We performed a four-month field experiment in a southeastern United States salt marsh to test the role of predatory crab diversity in regulating populations of a keystone grazer that can decimate marsh vegetation at high densities. Our results revealed that a combination of this system's two resident predator species, in comparison to individual species, both stabilize and strengthen predation rates on the potent grazer. Monthly monitoring of predation rates from intense, hot summer months into the cooler autumn indicate this diversity benefit arises from predators responding differentially to changing environmental conditions across seasons. This study provides some of the first experimental field support for the insurance hypothesis from marine ecosystems, suggests that predator temporal complementarity may be more common than currently perceived, and argues for conservation of predator diversity to ensure reliable and effective control of potentially habitat-destroying grazers.
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Russell, Anthony P., and Aaron M. Bauer. "The morphology of the digits of the golden gecko, Calodactylodes aureus and its implications for the occupation of rupicolous habitats." Amphibia-Reptilia 10, no. 2 (1989): 125–40. http://dx.doi.org/10.1163/156853889x00160.
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AbstractThe recent rediscovery of the golden gecko, Calodactylodes aureus, after more than 100 years, has given occasion to reconsider both its phylogenetic position amongst the gekkonine geckos and the functional aspects of its subdigital pads. The morphology of these pads and the anatomical basis of their control suggests that Afroedura among a grouping of gekkonine geckos with phenetically similar digits, shows the greatest structural similarity to Calodactylodes. Available data do not support a robust hypothesis of actual relationship between these two genera, but if relationship is not the underlying dictator of the similarity seen, the degree of convergence is remarkable. The general similarity in digital form of those genera possessing terminal, leaf-like scansors, both in the Gekkoninae and Diplodactylinae, appears to be associated with rupicolous habitats and indicates an evolutionary pathway by which more extensive climbing pads may have arisen. It is likely that this morphotypic pathway has been followed independently by several lineages of gekkonine and diplodactyline geckos.
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Capper, Daniel. "The search for microbial Martian life and American Buddhist ethics." International Journal of Astrobiology 19, no. 3 (November 14, 2019): 244–52. http://dx.doi.org/10.1017/s1473550419000296.
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AbstractMultiple searches hunt for extraterrestrial life, yet the ethics of such searches in terms of fossil and possible extant life on Mars have not been sufficiently delineated. In response, in this essay, I propose a tripartite ethic for searches for microbial Martian life that consists of default non-harm towards potential living beings, default non-harm to the habitats of potential living beings, but also responsible, restrained scientific harvesting of some microbes in limited transgression of these default non-harm modes. Although this multifaceted ethic remains secular and hence adaptable to space research settings, it arises from both a qualitative analysis of authoritative Buddhist scriptural ethics as well as the quantified ethnographic survey voices of contemporary American Buddhists. The resulting tripartite ethic, while developed for Mars, contains ramifications for the study of microbes on Earth and further retains application to other research locations in our Solar system.