Dissertations / Theses on the topic 'Feeding guild'

Group-living, within the Hymenoptera, is restricted to taxa in which females return to their nests repeatedly with food for their offspring (multiple provisioning), increasing the opportunities for helping (e.g. by guarding the nest). Some solitary wasps provide only one large prey item per cell (single provisioning). <i>Ammophila sabulosa</i> (Sphecidae) females provision half of their cells singly and half multiply. The costs and benefits of these two alternatives are compared in terms of : a. Total weight of prey (caterpillars) provided. b. Time taken to capture and transport prey. c. The probability of intraspecific theft of prey from cells. d. The incidence of parasitism by miltogrammine flies. There is no evidence that either strategy is more successful than the other. An advantage of flexible provisioning is suggested by a study of <i>Anoplius viaticus</i> (Pompilidae), females of which provision all cells singly with spiders. Despite provisioning prey of a smaller size range than does <i>Ammophila</i>, total prey weight in <i>Anoplius</i> cells is more variable and dependent upon seasonal changes in prey availability. <i>Ammophila</i> females steal caterpillars from each others' nests, and both they and <i>Anoplius</i> females brood-parasitize cells of conspecifics. Intraspecific parasitism as an alternative nesting strategy is discussed and compared with work on other solitary wasps. Patterns of resource utilization are documented for the guild of spider-hunting pompilid wasps at one site. Data were collected on : a. Microhabitat utilization. b. Seasonal occurrence. c. Female size distributions. d. Prey species and sizes. Observed patterns of utilization and overlap are compared with 'neutral' models of guild structure in which various aspects of the species x resources utilized matrix are randomized. Some of the results are consistent with the idea that interspecific competition has partly determined pompilid guild structure, but problems of methodology and interpretation are discussed.

The reintroduction of lions, cheetahs and African wild dogs to Kwandwe Private Game Reserve in the Eastern Cape Province of South Africa created the opportunity to study the biology and behaviour of these large carnivores in an enclosed system. The research focused on space utilisation and feeding ecology of the predators, using standard observational methods. Changes in the structure of the carnivore guild, and changes in the prey base that occurred during the study were used as natural experiments to examine factors affecting space use and diet. In general, the diets of the predators were similar to previous studies and prey abundance was more important than prey species size in determining prey selection. Changes in the abundance of certain prey species was matched by a dietary switch in lions from kudu to warthog and an increase in the proportion of springbok kills by the cheetahs. There was no significant difference in the proportions of prey species detected by ad hoc or continuous observations. Core areas occupied by the predators were significantly smaller than home ranges except when females were denning. Home ranges overlapped both within and between species, but there was very little overlap of core areas. An increase in the number of lion prides in the area during the study resulted in an increase in overlap of home ranges of lions and cheetahs, but did not result in a change in home range size. Space use by female cheetahs with cubs increased as the cubs grew older. The use of thicket vegetation by cheetahs decreased with an increase in the number of lion prides. Minimum Daily Energy Expenditure, energy intake and net benefit were calculated for the predators using data from continuous observations. All predators exhibited a large net benefit and the net benefit for single female cheetahs was greater than for the members of the coalition. Net benefit for the alpha pair of African wild dogs was lower than that of the pack.

Submitted by (ana.araujo@ufrpe.br) on 2016-08-22T11:40:08Z No. of bitstreams: 1 Carolina Alves Collier.pdf: 1967577 bytes, checksum: 200ee0c9c05fb39ab23840a268dff357 (MD5)<br>Made available in DSpace on 2016-08-22T11:40:09Z (GMT). No. of bitstreams: 1 Carolina Alves Collier.pdf: 1967577 bytes, checksum: 200ee0c9c05fb39ab23840a268dff357 (MD5) Previous issue date: 2012-02-28<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>The dynamics of resource partitioning among species from the same trophic guild, reduces competition and allows coexistence between them. Such sharing can result from different environmental performance and morphological changes resulting from the differential use of food resources. In this study, we evaluated the dynamic of partitioning of food resources in a guild of piscivorous fish, considering the ecomorphology and feeding of the species. Samples were collected monthly, between March/2007 and February/2008, the pond Curralinho, inserted in the semiaridnortheast. We evaluated the five most abundant species ofpiscivorous guild, and they are Acestrorhynchus lacustris, Acestrorhynchus britskii, Hoplias malabaricus, Pygocentrus piraya e Serrasalmus brandtii. The association of the informations trophics and ecomorphologicals of the evaluated piscivores resulted in similar patterns of clustering, demonstrating that the species that used different food resources, also possessed distinct morphological. The first group focused concentrated the two Serrasalminae species, while the second contained Hoplias malabaricus and two species of Acestrorhynchus. Among the species of Serrasalminae and Acestrorhynchus, morphological changes were not observed. However, among the members of Serrasalminae differences were observed in the strategies and food preferences, indicating a partitioning of resources between them. Such sharing can be evidenced by the intermediate value of dietary overlap between these two species. The food overlap index shows high values just within the group formed by H malabaricus and the two Acestrorhynchus species, however H. malabaricus differed in their strategy and food preference, which can contribute to reducing the potentialcompetitive with Acestrorhynchus. Just between the two species Acestrorhynchus did not show differences in strategy and food preference, indicating that theyhad the highest competitive potential between piscivorous evaluated. We emphasize the importance of the concomitant use of analysis ecomorphological and feeding, which is essential to a better understanding of the real trophic sharing.<br>A dinâmica da partilha de recursos, entre espécies de uma mesma guilda trófica, reduz a competição e possibilita a coexistência entre elas. Essa partilha pode decorrer do desempenho ecológico diferenciado resultante de variações morfológicas e da utilização diferenciada dos recursos alimentares. Neste estudo, avaliou-se a dinâmica da partilha de recursos alimentares numa guilda de peixes piscívoros, considerando a ecomorfologia e alimentação das espécies. As coletas foram realizadas mensalmente, entre março/2007 e fevereiro/2008, na lagoa Curralinho, inserida no semiárido nordestino. Foram avaliadas as cinco espécies mais abundantes da guilda dos piscívoros, sendo elas Acestrorhynchus lacustris, Acestrorhynchus britskii, Hoplias malabaricus, Pygocentrus piraya e Serrasalmus brandtii. A associação das informações ecomorfológicas e tróficas dos piscívoros avaliados resultou em padrões similares de agrupamento, demonstrando que as espécies que utilizaram recursos alimentares diferenciados, também possuíram padrões morfológicos distintos. O primeiro grupo concentrou as duas espécies de Serrasalminae, enquanto o segundo conteve Hoplias malabaricus e as duas espécies de Acestrorhynchus. Entre as espécies de Serrasalminae e Acestrorhynchus não foram observadas variações morfológicas. No entanto, entre os integrantes de Serrasalminae, foram observadas diferenças nas estratégias e preferências alimentares, indicando uma partilha dos recursos entre elas. Essa partilha pode ser evidenciada pelo valor intermediário de sobreposição alimentar entre estas duas espécies. O índice de sobreposição alimentar apresentou altos valores apenas dentro do grupo formado por H. malabaricus e as duas espécies de Acestrorhynchus,, entretanto H. malabaricus diferiu em sua estratégia e preferência alimentar, o que pode contribuir para a redução do potencial competitivo com Acestrorhynchus. Apenas entre as duas espécies de Acestrorhynchus não foram evidenciadas diferenças na estratégia e preferência alimentar, indicando que elas apresentaram o mais elevado potencial competitivo entre os piscívoros avaliados. Ressaltamos a importância da utilização concomitante de análises ecomorfológicas e de alimentação, que são indispensáveis para uma melhor compreensão da real partilha trófica.

Sandy beaches are often highly allochthonous, depending on external subsidies of carbon and nutrients. Despite this, sandy beach macrofaunal assemblages have received little attention regarding their response to enhanced primary productivity generated from coastal upwelling. This thesis investigates the influence of upwelling on macrofaunal assemblages over a variety of spatial and temporal scales. Spatially, four regions were examined across two biogeographic provinces to remove temperature as a confounding factor, and limit biogeography-specific effects. A nested hierarchical design enabled both large and small scales to be examined and generalities about upwelling effects across multiple areas to be considered. Sampling was conducted in two seasons, and over two years, to test the persistence of any effects. Biogeography and region had the strongest influences on macrofaunal biodiversity. Upwelling influenced macrofaunal assemblages in every region when analyses were conducted at the species level. However, the particular effect, positive or negative, differed among regions depending on local factors, and between the response variables, abundance and biomass. Coarser scales of taxonomy, feeding guild and developmental mode were investigated; however, the influence of upwelling generally became weaker and more varied, and occasionally disappeared. Seasonality was greater on the South Coast but was still important in some analyses on the West Coast. At the small-scale, variation within-beaches was lower than between beaches, assemblage structure remained stable over time, and consistent zonation was not present. The influence of temperature on filtration rate and oxygen consumption of Donax serra was investigated to test a driving mechanism for assemblage responses to upwelling. Feeding ability was significantly reduced at colder temperatures indicating an important factor which may be involved in determining assemblage structure. These results suggest that alterations to upwelling regimes predicted under climate change scenarios will impact sandy beach macrofauna, however the specific outcome will depend on multiple contextual factors.

Polybrominated flame retardants (BFRs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were analysed in eggs of various wild bird species from industrialised areas in South Africa. Eggs were collected during the 2008 – 2009 breeding season, homogenised and sent to the Norwegian School of Veterinary Science (NVH) for gas chromatography-mass spectrometry (GC-MS) analysis. The concentration, contamination profile, and risk assessment were conducted for each pollutant class, while effects of species-specific variation, feeding guild, and feeding habitat were investigated. Levels of BFRs ranged between 2.6 – 44 ng g-1 wet mass (wm). The predominant congeners were BDE-153, -154, - 183 and -47. Results indicated species, in close contact to humans, had higher levels of BFRs, even at lower trophic levels. Therefore, diet was not the primary route of exposure. High concentrations and the occurrence of nona-PBDE congeners and HBCD indicated exposure to current use BFRs. There were measurable levels of OCPs and PCBs in all eggs analysed. Median OCP concentration ranged from 4.2 – 623 ng g-1 wm. DDE was the predominant compound in all species with the exception of the Crowned Lapwing (Vanellus coronatus) where chlordanes were predominant. This may indicate a species-specific attribute in the metabolic efficiency or diet of the genus, since these findings have been reported elsewhere in literature. Congener profiles indicated historic sources of lindane and DDT, while low levels of p,p’-DDT in al species indicate long-range or atmospheric transport. Even though levels of p,p’-DDE were approaching toxicological thresholds, no eggshell thinning was evident. Concentrations of OCPs and PCBs showed an increase with increasing tophic level. PCB concentrations ranged between 0.9 – 296.4 ng g-1 wm. When studying the metabolic potential of PCBs, metabolic groups showed good agreement with the biodegradability of the individual congeners. Phenobarbital-type (PB-type) inducer PCBs were prevalent, indicating the predominance of less toxic PCB congeners. However, non-ortho PCBs were not analysed. These congeners aslo could impact on the toxic potential of PCBs in wild bird eggs. Principle component analysis (PCA) indicated that variances within datasets could be attributed to congener profiles within species as they were affected by exposure, diet, position in the food web, and association with human activities. Although the individual groups of organohalogens were below no observed effect levels (NOELs), negative effects could occur through interactions of various compounds with each other, as well as the unique exposure profiles of South African bird populations. To assess the dietary exposure of low-income human populations living close to large industries, the occurrence of organohalogens was investigated in backyard chicken eggs. Levels of dioxins in these eggs were above the European Union (EU) recommended limits, whereas BFRs and OCPs levels were below levels of concern. Nevertheless, areas where DDT is actively applied to dwellings for malaria control should be urgently investigated. The presence of measureable levels of all the compounds considered, indicate an environment seriously impacted by anthropogenic activity that in the long term could negatively affect both the environment and human health, if it has not already done so.<br>Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2011.

Trophic downgrading of ecosystems necessitates a functional understanding of trophic cascades. Identifying the presence of cascades, and the mechanisms through which they occur, is particularly important for seagrass meadows, which are among the most threatened ecosystems on Earth. Shark Bay, Western Australia provides a model system to investigate the potential importance of top-down effects in a relatively pristine seagrass ecosystem. The role of megagrazers in the Shark Bay system has been previously investigated, but the role of macrograzers (i.e., teleosts), and their importance relative to megagrazers, remains unknown. The objective of my dissertation was to elucidate the importance of teleost macrograzers in transmitting top-down effects in seagrass ecosystems. Seagrasses and macroalgae were the main food of the abundant teleost Pelates octolineatus, but stable isotopic values suggested that algae may contribute a larger portion of assimilated food than suggested by gut contents. Pelates octolineatus is at risk from numerous predators, with pied cormorants (Phalacrocorax varius) taking the majority of tethered P. octolineatus. Using a combination of fish trapping and unbaited underwater video surveillance, I found that the relative abundance of P. octolineatus was greater in interior areas of seagrass banks during the cold season, and that the mean length of P. octolineatus was greater in these areas compared to along edges of banks. Finally, I used seagrass transplants and exclosure experiments to determine the relative effect of megagrazers and macrograzers on the establishment and persistence of three species of seagrasses in interior microhabitats. Teleost grazing had the largest impact on seagrass species with the highest nutrient content, and these impacts were primarily observed during the warm season. My findings are consistent with predictions of a behaviorally-mediated trophic cascade initiated by tiger sharks (Galeocerdo cuvier) and transmitted through herbivorous fishes and their predators.

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No. of bitstreams: 1 LianaMPC_DISSERT.pdf: 2474434 bytes, checksum: f2bb5ffb379f9469038f03a2e7fdd955 (MD5) Previous issue date: 2016-03-28<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>In semiarid regions, as the Caatinga, the rains distribution can determine the food availability and the intensity of hydric stress. This, with frequency, affects breeding aspects of birds, as time, length and reproduction intensity. In this study we have tested the hypothesis: (1) The breeding of the sampled species is restricted to the rainy season characteristic of the region; (2) Intra-annual variations in the rains’ volume and frequency are correlated with the quantity of individuals and species reproducing; (3) the species of the community reproducing in a way temporally jointly, independent of the feeding guilds. The study was accomplished in Caatinga’s region, with assessments every 14 days of brood patch occurrence. Three reproductive cycles was studied between september-2012 and october-2015. It was utilized the Cross-Correlation Function – CCF to verify the relation existing between the rains and the breeding birds. Altogether, 46 species (377 records) were observed with patches. The reproduction occurred in a seasonal way between february and july, with 94% of the records of patches restricted to the period. The intensity and duration of the breeding (total of individuals and species) was significantly correlated with the rains, when considered the time lag of 14 days. The length (140, 168, and 154 days) and time (march/02 to july/20, February/01 to july/19, February/12 to july/18) of breeding differed between three reproductive cycles. The analysis by feeding guild (insectivore-restrictive, insectivore-frugivorous, insectivore-granivorous and omnivorous) resulted in a similar pattern to general, mainly when it’s considered the correlation and time lag with the rains. Our study indicates that the breeding birds in the Caatinga’s area studied it was not just, generally, related to rainy seasons, as it was break out via answer of short deadline to the rainfall intensity. Including having it period, length and intensity regulated by this climatic factor or by other factors correlated to rains (g.e. food availability)<br>Em regiões semiáridas, como a Caatinga, a distribuição das chuvas pode determinar a disponibilidade do alimento e a intensidade do estresse hídrico. Isso, com frequência, afeta aspectos reprodutivos das aves, tais como época, comprimento e intensidade da reprodução. Neste estudo, testamos as hipóteses: (1) A reprodução das espécies amostradas é restrita ao período chuvoso característico da região; (2) variações intra-anuais no volume e na frequência das chuvas estão correlacionadas com a quantidade de indivíduos e espécies se reproduzindo; (3) as espécies da comunidade se reproduzem de forma temporalmente conjunta, independentemente da guilda alimentar. O estudo foi realizado em uma região de Caatinga, com avaliações a cada 14 dias de ocorrência de placa de incubação. Três ciclos reprodutivos foram estudados entre set-2012 e out-2015. Foi utilizada a Função de Correlação Cruzada (Cross-correlation Function – CCF) para verificar a existência de relação entre as chuvas e a reprodução das aves. Ao todo, 46 espécies (377 registros) foram observadas com placas. A reprodução ocorreu de forma sazonal entre fevereiro e julho, com 94% dos registros de placas restritos ao período. A intensidade e a duração da reprodução (total de indivíduos e de espécies) foram significativamente correlacionadas com as chuvas, quando considerado o time lag de 14 dias. O comprimento (140, 168 e 154 dias) e a época (02/mar a 20/jul, 01/fev a 19/jul, 13/fev a 18/jul) da reprodução diferiram entre os três ciclos reprodutivos. As análises por guilda alimentar (insetívoro-restritivo, insetívoro-frugívoro, insetívoro-granívoros e onívoros) resultaram em padrão semelhante ao geral, principalmente quando considerada a correlação e time lag com as chuvas. Nosso estudo indica que a reprodução das aves na área de Caatinga estudada não só esteve, de modo geral, relacionada às épocas chuvosas, como foi deflagrada via resposta de curto prazo à intensidade da precipitação. Inclusive, tendo seus períodos, comprimentos e intensidades regulados por este fator climático ou por outros fatores correlacionados às chuvas (e.g. disponibilidade de alimento)<br>2017-03-23

A drive into the country will soon confirm the effects of agriculture on the environment. Different agricultural practices such as vast fields of monocultures, forests of exotic timber, and large intensive feed lots of livestock, will be evident. The need to provide food for an increasing population particularly in Africa is the driving force behind the intensification of agriculture. The production of increased food supply is often considered without knowledge of the impacts on the environment. The North East District of Botswana is a small district compared to other districts of Botswana but unlike these large districts the population density is comparably high with a demand for agricultural space. Botswana is a desert margins area under threat of desertification with many signs of desertification being evident throughout the country. The main agricultural activity in the North East District is livestock farming with horticulture being practiced on the banks of sandy river beds. The district provided an ideal area to compare the impacts of different livestock farming techniques. Four different approaches of livestock farming were examined with the number of livestock cattle in particular, being a noticeable difference and the grazing intensity of these cattle being another important difference. This study examined the impacts of these different grazing techniques on the environment with a particular reference to birds. Data was collected using a point count system with 28 points evenly spaced in a grid across the different land uses. Each point was subject to a total of six surveys with summer and winter having three surveys each. It was expected that bird numbers and species would be impacted by the grazing intensity while the different feeding and nesting guilds may also respond to grazing intensity. Statistical analysis included geostatistical analysis, uni-variant, mult-variant and non-metric multi-dimensional scaling. The results show that birds were impacted by grazing intensity with species richness and bird numbers being negatively affected. However, feeding and nesting guilds were impacted differently. Climate change and land degradation are a reality and will impact on avian diversity and sound management practices need to be implemented to protect biodiversity in marginal areas.<br>Thesis (Master of Environmental Sciences)--North-West University, Potchefstroom Campus, 2013

Les sols représentent environ 63% des émissions de N2O et à eux seuls les sols tropicaux représentent 23% de ce budget soit une contribution bien plus élevé que les sols tempérés. Ces sols sont connus pour abriter une grande biodiversité d'invertébrés dominés par quatre types i.e. termites, vers de terre, fourmis et larves de scarabaeid. Ces groupes macrofaunal sont considérés comme des ingénieurs des sols via notamment leurs actions de régulation de la disponibilité des ressources chimiques, tels que l'azote minéral pour les micro-organismes. Cette régulation est due à leurs capacités de digestion spécifiques de la matière organique ainsi que la création et/ou la modification des habitats des sols. Cette étude est basée sur l'hypothèse suivante (i) l'environnement digestif et les structures biogéniques de ces ingénieurs du sol sont considérées comme des « hot spot » d' émissions de N2O (ii) les taux d'émission de N2O varient en fonction de leurs régimes alimentaires, cette macrofaune ingérant des substrats avec différents C:N (iii) le taux d'émission de N2O de chaque invertébré est corrélé à la densité des communautés bactériennes digestives impliquées dans l'émission de N2O (bactéries nitrifiantes et dénitrifiantes) et à leur teneur en azote minéral dans leur tube digestif. Pour évaluer ces différentes hypothèses, des mesures des taux d'émission de N2O ont été effectuées in vitro en aérobiose pour la macrofaune (30 espèces différentes en provenance d'Afrique, d'Amérique du Sud et d'Europe) et leurs matériels biogéniques associées (nids, turricules). L'abondance des gènes fonctionnelles des bactéries nitrifiantes (AOA et AOB) et dénitrifiantes (nirK, nirS, nosZ) ont été quantifiés par PCR quantitative. Les termites humivores et champignonnistes ainsi que les larves de scarabaeid émettent des quantités significatives de N2O alors que les fourmis n'en émettent pas. Quand aux termites xylophages et litièrivore, ils absorbent le N2O. Les structures biogéniques des vers de terre (turricules) et des fourmis (nid) émettent des quantités importantes de N2O ce qui n'est pas le cas des nids de termites. La faune du sol et leurs structures biogéniques associées, sont donc, dans la majorité des cas étudiés, un lieu d'émission de N2O, confirmant ainsi notre première hypothèse. Ce travail a également démontré qu'il y a avait une étroite corrélation entre régime alimentaire et intensité de l'émission de N2O au sein de chaque type de macrofaune étudié. En revanche, l'abondance des gènes des communautés digestive nitrifiantes et dénitrifiantes et le contenu en N minéral au sein du tube digestif ne semblent pas être des proxies pertinents des émissions de N2O. A partir de ces mesures, des calculs ont été effectuées pour déterminer l'importance de ces émissions à l'échelle des écosystèmes tropicaux étudiés (forêt et savane). Ces calculs suggèrent que la macrofaune du sol dans ces écosystèmes pourrait contribuer entre 0,1 à 11,7% et 0,1 à 8,8% du budget total des émissions de N2O, respectivement. Les résultats de ces travaux devraient contribuer à une meilleure prise en compte de la composante biotique dans la modélisation des émissions de gaz à effet de serre provenant des sols en milieu tropical<br>Soils account for about 63% of N2O emissions. Tropical soils are estimated to emit 23% of global N2O emission budget which is much higher than temperate soil N2O emissions. These soils also harbor a huge biodiversity of invertebrates dominated by four types of macrofauna i.e. termites, earthworms, ants and scarabaeid grubs. These macrofaunal groups are considered as soil engineers because they regulate the availability of chemical resources, like mineral nitrogen, for the microorganisms via their specific digestion capabilities and/or by creating and modifying soil habitats. This study is based on the following hypothesis (i) the gut environment or biogenic structures of these soil engineers are considered as hotspots of N2O emission (ii) the N2O emission rates will vary according to their feeding behavior as these macrofauna thrive on diverse substrates with different C:N ratio (iii) the rate of N2O emission in each soil fauna will also depend on the gut density of the bacterial communities involved in the N2O emission (nitrifiers and denitrifiers) and on the mineral nitrogen content within the gut. To assess these different hypotheses in-vitro short-term N2O emission rates were assessed for either live macrofauna (30 species collected from Africa, South America and Europe) or their biogenic materials or both under aerobic incubations. Genes abundance of nitrifiers (AOA and AOB) and denitrifiers (nirK, nirS, nosZ) were quantified by real time quantitative PCR. Soil-feeders and fungus-growing termites and scarabaeid grubs emitted in-vivo N2O while ants did not. Surprisingly, wood- and grass-feeding termites revealed an uptake of N2O. Biogenic structures of earthworms and ants emitted substantial amount of N2O while those of termites did not. The emission difference between macrofauna or their biogenic materials and their control materials was significant for most of the macrofaunal groups studied confirming our first hypothesis. We also confirmed that the feeding behavior (total N content and C:N ratio of food material) is the main factor explaining the observed N2O emission pattern of each macrofaunal group investigated whereas genes abundances, particularly of denitrifiers and gut N mineral content did not appear to be relevant proxies of the N2O emissions rates. A back-on-the-envelope data upscaling suggests that soil macrofauna could contribute from 0.1–11.7% and 0.1–8.8% of the total soil N2O emissions, respectively, for the tropical rainforest and dry savanna ecosystems. This work should contribute to a better estimation of the soil biotic compartment in the different models of greenhouse gas emissions from tropical soils

Worldwide degradation and conversion of tropical forests affects many species and their provided ecosystem services. Among them are birds, responsible for pollination, seed dispersal, pest control and scavenging. This study, conducted in southwest Ethiopia, compares species composition and bird functional diversity between forest and homegardens close to and far from forest, both in terms of species numbers and bird abundances. Point counts and mist netting were used to obtain data. While the former method detected more species, abundance data from the latter revealed patterns not observed by just comparing species numbers. I found that species diversity was lower in forest compared to gardens and that the species composition of both communities was significantly distinct. Whereas forest had more forest specialists, gardens held more forest visitors and species of open country. Close and far gardens did not differ in any aspect, except that abundances of forest generalist birds were somewhat higher close to forest. Regarding bird feeding guilds, I found that granivores and nectarivores were more numerous in gardens, while frugivores were more common in forest. Carnivores and omnivores showed no effect. Insectivore proportions were the same for forest and farmland, but their numbers (including those of all sub-guilds) were higher in gardens. The Ethiopian forest avifauna is poor in comparison with other Afromontane regions, lacking several, mostly insectivorous genera. This could be the result of an extinction after which its geographic isolation made recolonization difficult, especially for dispersal-limited understory species. Nonetheless, and despite their impoverished state, the results suggest that forest remnants are important for forest-dependent species, being a stronghold for forest specialists and supporting higher numbers of forest generalists in nearby gardens. However, future forest regrowth might be at stake with ongoing agricultural encroachment, because gardens hold fewer frugivores, especially forest specialists, which might affect seed dispersal.<br>Många arter påverkas negativt av avskogning och annan mänsklig påverkan på tropiska skogar, vilket också kan få konsekvenser för de ekosystemtjänster dessa arter levererar. En viktig artgrupp i detta avseende är fåglar, som kan ha betydelse för pollination, fröspridning, naturlig skadedjurskontroll och som asätare. Denna studie, utförd i sydvästra Etiopien, jämför artsammansättning och funktionell diversitet hos fåglar i skogar och trädgårdar både nära och långt ifrån skogen. Både antal arter och antal individer har undersökts. Data materialet bygger både på observationer från punktinventering och fåglar fångade med slöjnät. Med den första metoden noterade jag fler arter, medan abundansvärden från den andra metoden gjorde att jag såg mönster som inte syntes vid endast jämförelser av artrikedom. Jag fann att artrikedomen var lägre i skogen i jämförelse med trädgårdarna, men att artsammansättningen var signifikant skiljd däremellan. Skogarna hade fler skogsspecialister medan trädgårdarna hade fler arter från öppna marker och tillfälliga skogsbesökande arter. Trädgårdar som låg nära eller långt ifrån skogen skiljde sig inte på något sätt utom att individtätheten av skogsgeneralister var något högre i trädgårdar nära skogen. När det gäller uppdelningen av fåglarna utifrån vad de äter så fann jag att fröätande och nektarätande arter var vanligare i trädgårdar medan fruktätande arter var vanligare i skogen. Rovfåglar och allätare uppvisade inget tydligt mönster. Proportionen insektsätande fåglelarter var samma i skogen och trädgårdarna, men det absoluta antalet arter (inklusive alla olika underkategorier) var högre i trädgårdarna. Den etiopiska skogsfågelfaunan är artfattig i förhållande till andra bergstrakter i Afrika och saknar flera släkten av framförallt insektsätande fåglar. Detta skulle kunna bero på ett tidigare utdöende varefter en senare återkolonisering varit svår på grund av den geografiska isoleringen, speciellt för insektsätande fåglar som huvudsakligen finns i undervegetationen. Trots den relativa artfattigdomen så visar resultatet från min studie hursomhelst på att skogarna är viktiga för skogsberoende fåglar. Den största betydelsen har de för skogsspecialister där, men även genom en positiv effekt på abundansen av skogsgeneralister i närliggande trädgårdar. Dock kan framtida återväxt av skogar bli problematisk på grund av en pågående omvandling av skogar till trädgårdar, eftersom trädgårdar hyser färre fruktätande fåglar, vilket kan påverka fröspridning över landskapet.<br>Examining mismatches between management and the supply of ecosystem services in Ethiopian agroecosystems across scales in space and time

Submitted by João Henrique Costa (henrique@biblioteca.ufpb.br) on 2016-12-19T14:32:19Z No. of bitstreams: 1 Arquivototal.pdf: 2635026 bytes, checksum: 13eda8fbce0b59e5bba1b505be4cfed4 (MD5)<br>Made available in DSpace on 2016-12-19T14:32:19Z (GMT). No. of bitstreams: 1 Arquivototal.pdf: 2635026 bytes, checksum: 13eda8fbce0b59e5bba1b505be4cfed4 (MD5) Previous issue date: 2016-07-28<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>The present study aimed to characterize a fish assemblage along a mangrove-reef gradient at Barra do Rio Mamanguape Environmental Protected Area, Paraíba, Brazil, according to the following parameters: spatial distribution, habitat use, feeding ecology and trophic guilds. This dissertation is divided in two chapters: the first one aims to describe the spatial and seasonal distribution, habitat use and ontogenetic shifts on estuary usage; the second one registers fish diet according to region, season and size classes of most abundant species as well as the trophic. Fish samples were gathered using three types of nets along seventeen sites, grouped in four regions according to salinity range: Reefs, Low, Middle and Upper estuaries. Most abundant species were Atherinela brasiliensis and Sphoeroides testudineus. Among the guilds, piscivores were the most abundant, followed by crab eaters. Herbivores were found with higher abundance in reefs. We registered differences in guilds distribution along the mangrove-reef gradient and according to seasons (dry and rainy). Caranx latus, Oligoplites palometa and Mugil curema occupied different regions in different life stages. We registered differences in guilds distribution along the mangrove-reef gradient and according to seasons (dry and rainy).<br>O presente trabalho objetivou caracterizar a ictiofauna ao longo de um gradiente estuarino-recifal na APA Barra do Rio Mamanguape, Paraíba, Brasil, utilizando os seguintes parâmetros: distribuição espacial, uso do habitat, dieta e formação de grupos tróficos. O trabalho foi dividido em dois capítulos, onde o primeiro trata da distribuição espaço-temporal, uso do habitat e mudanças ontogenéticas no uso do estuário; o segundo, descreve a dieta das espécies e registra a formação de grupos tróficos, bem como a dieta das espécies abundantes de acordo com o local e estação em que foram coletadas e pelas classes de tamanho. Foram utilizados arrastos, tarrafas e agulheiras a fim de coletar os peixes e a dieta foi determinada a partir da análise dos conteúdos gástricos. As coletas foram realizadas ao longo de 17 pontos, divididos em quatro regiões a partir do gradiente de salinidade: Recifes, Baixo Estuário, Estuário Médio e Alto Estuário. As espécies mais abundantes foram Atherinela brasiliensis e Sphoeroides testudineus. A maior média de tamanho dos indivíduos foi registrada para a zona recifal, a qual apresentou uma maior contribuição de herbívoros em relação às regiões do estuário. Espécies como Caranx latus, Oligoplites palometa e Mugil curema apresentaram diferenças na preferência do habitat ao conforme ontogenia. A maior parte das espécies registradas no presente estudo foi considerada de origem marinha, podendo depender direta ou indiretamente do estuário. Em relação aos grupos tróficos, o grupo com maior número de representantes foram os Piscívoros, seguidos pelos que se alimentaram de Brachyura. A distribuição dos grupos tróficos também apresentou entre as regiões amostradas e também sazonalmente.

Made available in DSpace on 2016-06-02T19:29:26Z (GMT). No. of bitstreams: 1 3114.pdf: 4153155 bytes, checksum: 9c4f4c3e1041563aa6254cc622f8352d (MD5) Previous issue date: 2010-05-28<br>Financiadora de Estudos e Projetos<br>Studies on the feeding of fishes provide relevant information for understanding the mechanisms allowing the coexistence and exploitation of resources by several species of fishes and also by other components of the aquatic communities.. The objective of the present study was to analyze in detail the feeding habits and the ecomorphology of the fish species Pimelodus fur and Leporinus reinhardti as well as to preliminarily characterize the fedding habits and describe the morphological characteristics of other nine species of fish occurring in a stretch of the Upper São Francisco River Basin. Fishes were sampled in four periods: December 2006 and 2008 (rainy periods) and April 2007 and June 2008 (dry periods) using with gillnets, seine nets and sieve. The results on the feeding ecology of P.fur revealed that this species belong to the trophic gulid of the insectivores, since insects represent between 74.0% and 79.0% of its diet. There were seasonal changes in the diet of P. fur, with food items essentially authochtonous, as aquatic insects larvae being consumed in the dry periods and insects from terrestrial sources, as Araneae and Hymenoptera being added to its diet during the rainy periods, in both São Francisco River and its tributary Piumhi River. In these rivers P. fur displayed high trophic specialization, being a specialist in consuming aquatic insects. It was also observed great overlap in the food items consumed by the different size classes of P. population sampled in both rivers. L. reinhardti had intense feeding activity in both seasons dry and rainy periods. This species belong to the trophic guild of herbivores, being its diet composed mainly by plant material. The feeding spectrum of L. reinhardti is wider in São Francisco River than in the Piumhi River, what can be a consequence of the fact that the gallery forest in the São Francisco River is better preserved in this region than that of the Piumhi River. There were seasonal changes in the diet of L. reinhardt, with some food items as Trichoptera and Hymenoptera only being consumed in the rainy periods. There was no significant change in the diet of L. reinhardti along its development, with preference by plant material in all size classes. L. reinhardti is a feeding specialist with narrow niche breath. There was no feeding niche overlap between P. fur and L. reinhardti in any seasonal period or river stretch studied. Although feeding activity of both P. fur and L. reinhardti was intense during all periods analyzed, the narrow feeding niche breath and the large diet overlap among the size classes within each species population indicate that food sources are abundant in this part of the Upper São Francisco River basin. Regarding the morphological characteristics there was also trophic structuring of the species studied in Piumhi and São Francisco Rivers, with segregation between the body shape of the specialists (insectivores and piscivores) and the more generalist feeders (omnivores and herbivores).<br>Os estudos sobre a alimentação de peixes fornecem informações importantes para a compreensão dos mecanismos que permitem a coexistência e exploração dos recursos por várias espécies de peixes e pelos demais componentes das comunidades aquáticas. O objetivo deste estudo foi analisar detalhadamente o hábito alimentar e a ecomorfologia das espécies de peixe Pimelodus fur (mandi-branco) e Leporinus reinhardti (piau-de-três-pintas), bem como descrever preliminarmente os hábitos alimentares e as características morfológicas de outras nove espécies de peixes com ocorrência em um trecho da bacia do alto rio São Francisco. Os peixes foram coletados em dezembro de 2006 e dezembro de 2008 (períodos chuvosos) e abril de 2007 e junho de 2008 (períodos secos), utilizando-se redes de espera, redes de arrasto, tarrafas e peneiras. Os resultados sobre a alimentação de P. fur revelaram que esta espécie pertence à guilda trófica insetívora, sendo que os insetos representaram entre 74 a 70% de sua dieta. Foi observada variação estacional na alimentação de P. fur, com itens alimentares essencialmente autóctones sendo consumidos no período de seca (larvas de insetos aquáticos) e com artrópodos de origem terrestre (Araneae e Hymenoptera) sendo adicionados à sua dieta no período chuvoso em ambos os rios estudados, Rio São Francisco e Rio Piumhi. Nos rios estudados P. fur apresentou elevada especialização trófica, sendo uma espécie especialista no consumo de insetos aquáticos. Verificou-se também elevada sobreposição alimentar entre as diferentes classes de tamanho de P. fur na população amostrada em ambos os rios. L. reinhardti tem uma alta atividade alimentar em ambos os períodos climáticos, seca e cheia. A espécie L. reinhardti pertence à guilda alimentar herbívora, sendo a sua dieta composta preferencialmente por vegetais superiores. O espectro alimentar de L. reinhardti é mais amplo no Rio São Francisco, do que no Rio Piumhi, provavelmente pelo fato desse trecho do rio apresentar vegetação ciliar mais preservada. Verificou-se variação estacional na alimentação do piau-três-pintas, onde alguns itens como fragmentos de insetos, Trichoptera e Hymenoptera só foram consumidos na estação chuvosa. Não houve variação na dieta ao longo do desenvolvimento de L. reinhardti, sendo observada a preferência por material vegetal em todas as classes de tamanho. L. reinhardti é um peixe especialista, com pequena amplitude de nicho em todas as classes de tamanho. Não ocorreu sobreposição alimentar entre P. fur e L. reinhardti em nenhum dos períodos ou rio avaliados. Embora a atividade alimentar de P. fur e L. reinhardti tenha sido intensa em todos os períodos, a pequena amplitude do nicho e a grande sobreposição alimentar entre as diferentes classes de tamanho em cada espécie sugere que os recursos alimentares sejam abundantes neste trecho do Alto Rio São Francisco. Observou-se estruturação trófica quanto à morfologia das espécies estudadas nos rios Piumhi e São Francisco, com a separação entre as formas do corpo das espécies mais especialistas (insetívoros e piscívoros) daquelas das espécies mais generalistas (onívoro e herbívoro).

A riparian ecosystem is the area between the aquatic and terrestrial setting of a stream, and serves as a corridor and habitat for birds. Several riparian ecosystems are located in urban environments, and three main riparian corridors are located in Potchefstroom. They are the Mooi River, Wasgoed Spruit, and Spitskop Spruit, which encompass a wide range of different vegetation types and anthropogenic factors. Therefore, different habitat types for birds occur along the riparian corridors of Potchefstroom. Factors such as food and water availability, nesting sites, competition, predation, learning, presence of other species, and those species that are able to adapt to environmental changes influence the avian diversity and communities along riparian corridors. The hypothesis is that bird variables along the riparian corridors in Potchefstroom are affected by vegetation, anthropogenic, and seasonal influences. To investigate these affects, two secondary objectives were formulated. The first was to characterise riparian avian habitats (CAHs) according to vegetation and anthropogenic factors, and the second was to identify temporal and spatial changes in avian variables. The three streams were divided into 79 consecutive transects, each 300 m long. The study area consisted of: 17 transects along Spitskop Spruit, 12 along Wasgoed Spruit and 50 along the Mooi River. Bird observations were conducted monthly from June 2006 to June 2007. Birds that were observed with a perpendicular distance ≤ 30 meters towards the streams were included in the results. The bird species that were observed were also classified into different nesting and feeding guilds. Environmental data recorded included: vegetation structure (estimated cover percentages and height classes of trees, shrubs, grasses, herbs, sedges, and reeds), anthropogenic structures (estimated cover percentages of roads, footpaths, bridges, electrical pylons, houses, and drainage pipes), and the presence of informal settlers along each transect (the mean number of people and the space they occupy). Vegetation was monitored in summer– (February 2007 until April 2007) and winter months (June 2007 until August 2007). The anthropogenic structures and the presence of informal settlers (anthropogenic factors) were monitored simultaneously with the bird counts. Transect-time profiles were drawn for the four parameters, which differed on spatial and time scales. Multivariate analyses included non-metric multidimensional scaling (NMS), cluster analysis, and indicator species analysis. Cluster analyses and NMS bi-plots were used to define characterised avian habitats (CAHs). Two types of CAHs were characterised: Summer CAHs (summer vegetation and anthropogenic factors) and Anthropogenically CAHs (Anthropogenic factors alone). Bird species were then ordinated with the summer and anthropogenically CAHs on NMS successional vector graphs. The successional vectors illustrate the avian community trajectories of the different CAHs. Indicator species analyses were performed to describe associations between the bird species and the summer and anthropogenically CAHs. The summer and anthropogenic CAHs that were characterised had different avian community trajectories and different species were associated with these CAHs. Different levels in avian diversity appeared among these CAHs, and convergence and divergence in communities appeared among these CAHs. Birds also selected their habitats according to feeding and nesting behaviours. Consequently, it can be deduced that environmental factors such as vegetation structures and anthropogenic factors, as well as seasonality, had an effect on the distribution of birds along the riparian corridors of Potchefstroom.<br>Thesis (Master of Environmental Sciences)--North-West University, Potchefstroom Campus, 2013

El objetivo de esta tesis es estudiar el efecto del enriquecimiento por materia orgánica producida por el cultivo de peces en el mar y por los vertidos de petróleo en el medio marino. Este trabajo intenta explicar las consecuencias ecológicas de los impactos generados por este tipo de contaminación, y en diseñar de test de toxicidad para evaluar la contaminación en el sur de las costas europeas. Específicamente, en relación con el impacto de la acuicultura, los estudios de recuperación durante la Apertura de peces bentónicos de reducción de piscicultura marina, el papel de la depredación en el sistema bentónico dispersión de los residuos y los vínculos horizontales y verticales con un impacto bentónico.<br>The aim of this thesis is to study the effect of organic matter enrichment produced by marinefinfish farming and oil spills on the marine environment. This work is focused on elucidating theecological consequences of the impact generated by this type of pollution, and on designingtoxictity tests to evaluate pollution for southern European coasts. Specifically, related with aquaculture impact, it studies benthic recovery during open sea fish farming abatement, the role of predation in the benthic system and links horizontal and vertical waste dispersion with benthic impact.

博士<br>國立臺灣大學<br>動物學研究所<br>91<br>In order to reveal the feeding habits, food resource partitioning and guild structure of odontocetes in Taiwanese waters, the stomach contents were used to identify and enumerate the prey they consumed. Using data collected during 1994 to 2001, which included a total 150 stomach samples collected from 14 odontocetes species. The Risso’s dolphin predominantly fed on enoploteuthid squid, with 90.5% of total number of prey. The diet of Fraser’s dolphin was dominated by hatchetfish, with total prey count of 50.6%. The pantropical spotted dolphin primarily consumed lanternfishes which comprised 49.8% of total number of prey. The diet composition of these three dolphins all showed seasonal variation. The food niche width (B=1.6) of Risso’s dolphin was much narrow than that of Fraser’s dolphin (B=4.4) and pantropical spotted dolphin (B=5.1). The low global overlaps found among the food niches of those three sympatric dolphins, indicating that they have succeeded in partitioning the food supply. Difference in feeding depth and food preferences could reduce the direct food competition. Enoploteuthis chunii, Sthenoteuthis oualaniensis and Taonius pavo was the primary prey in the diet of pygmy sperm whale, while E. chunii, Histioteuthis miranda and T. pavo were the most important preys ingested by dwarf sperm whale. Although the primary preys they ingested were very similar, the ratio of each primary prey comprised differently. Pygmy sperm whale fed on much larger T. pavo than those were ingested by dwarf sperm whale, while dwarf sperm whale ingested more H. miranda than pygmy sperm whale did. This result supports the view that the pygmy sperm whale lives seaward of the continental shelf and the dwarf sperm whale lives in the more coastal waters. Five major feeding guilds were identified by cluster analysis, which included a total 150 stomach samples collected from 14 odontocetes species. The first to forth group were predominantly fish eaters, while the fifth group comprised all teuthivorous odontocetes. The odontocetes off west coastal Taiwan fed primarily on croakers (Sciaenidae), needlefishes (Belonidae), jacks (Carangidae), octopus (Octopidae) and loliginid squid (Loliginidae). Off eastern Taiwan waters, the lanternfishes (Myctophidae), enoploteuthid squid (Enoploteuthidae) and flying squid (Ommastrephidae) were primarily consumed by odontocetes. The dendrogram of guild structure was very close to dendrogram of phylogenetic relationships among delphinid cetaceans. The third group belonged to the subfamilies Delphininae, the forth group belonged to Stenoninae and the second guild in fifth major group belonged to Globicephalinae in this study. The odontocetes in the same guilds could reduce the competition by partitioned the habitat spatially and temporally.

碩士<br>國立海洋大學<br>海洋生物研究所<br>90<br>Tidepool is a specific marine ecological habitat, and effected by human beings increase daily. Thus, the ecological studies of tidepool have been noticed recently. However, the ecological investigations of intertidal fishes are few in these twenty years. The diet studies of intertidal fishes are also not enough. The aims of this study are to understand the trophic structure and dynamics of tidepool fishes. Feeding guild is defined as a group of species uses the same or similar resource in a similar way. Food partition among intertidal fish assemblage is the main process to divide community structure. Hence, The identification and analysis of the feeding guild is important fundamental method to understand how the community organize and structure. Tidal pool fishes were collected with anesthetic-clove oil, and then the diet shift and feeding guild of fishes was analyzed with both gut contents and stable isotope. Fishes were collected from the tidal pools of Patotz, Yehliu, Aoti of northern Taiwan and Checheng, Hsiangchiaowan, Jiupeng of southern Taiwan during January and October 2001. We collected 17 families, 52 species of tidepool fishes, and the dominant families, Blennidae, Gobiidae and Pomacentridae are the main investigative fishes. This study is the one of the fewresearches on intertidal fishes in tropical east Pacific Ocean, and also the few research of the diets of tidal pool fishes in Taiwan (tropical area). The main trophic structure of tidal pool fish assemblages in Taiwan was herbivores (33~52%). Comparing with the proportion of herbivores (4~16%) in temperate area, herbivores are morn dominant and important in Taiwan. Comparison between north and south Taiwan might be considered as the comparison between tropical and subtropical area. The results show that there is tendency of difference, but not significant. Spatial variations in the diets of tidal pool fishes show no significance, and the result is the same with the identical family or genus of fishes in other area. Seasonal changes in diet are discovered in herbivorous fishes of tidal pool. After comparing with abundance of food resource, seasonal diet shift pattern are relative with resource abundance was suggested. Most of tidal pool fishes in Taiwan have ontogenetic diet change. The food categories are changed and prey sizes are increasing during their growth. Feeding guild structure is determinately changing with ontogenetic diet shift existing. Hence using ontogenetic trophic unit as a feeding guild unit is more suitable. Stable isotope analysis is used to avoid the mistake of gut contents analysis, but also shows the same result with gut contents analysis. However, stable isotope analysis can not have high resolution as gut contents analysis. Another possibility is that food items are over partitioned in gut contents analysis, and not consist with the natural condition. Stable isotope analysis can not built the feeding guild with statistical significant as gut contents analysis is our unsolved problem. The feeding guilds built from gut contents analysis are not significant different in stable isotope analysis, too. Finally, we suggest that when feeding guild was built by gut contents analysis, assisted by the result of stable isotope analysis to make choices of food items. We believe the result of feeding guild will more consist with nature.

碩士<br>國立中山大學<br>海洋生物科技暨資源學系研究所<br>103<br>In order to investigate the dietary shift of the bigeye tuna in western Indian Ocean, the stable isotope of 117 stomach tissues, 32 muscle tissues and 129 food items of bigeye tuna were analyzed. Moreover, 50 fish and shrimp samples collected from southwestern Taiwan were also analyzed. The results show that both the carbon and nitrogen stable isotope were found different between the bigeye tuna’s stomach and muscle tissues. The δ13C values in stomach were higher than those of muscles, but δ15N values were opposite. The difference was as a result of the different tissues turnover rate of the stomach and muscle tissues. We found that the stable isotope values of stomach and muscle tissues, representing short-(day) and long-term (yearly), respectively, nutrient turnover rate. Small size of bigeye tuna (FL<185 cm), prefer prey on Charybdis smithii and Alepisauridae larvae, had lower δ15N value than the big ones (FL>185 cm). Because of the bigeye tuna prey on more crustacean between July and September, so that they had lower δ15N values than the tuna in other seasons. We found that the size segregation and seasonal shift in the diet of bigeye tuna cause the variation of δ15N values. The highest and lowest δ15N values of the prey of bigeye tuna was Scopelarchus analis (14.21 ± 0.64‰) and Oplophorus gracilirostris (10.06 ± 1.47‰). Influence by prey’s body length, construct of the local food web and the environmental factor, the bigeye tuna’s prey had higher δ15N values than literature records. We speculate that the bigeye tuna from western Indian Ocean prey on lower trophic level prey in a long period, and accumulated lower δ15N, and as a result that their trophic level are overlap between bigeye tuna and their preys in western Indian Ocean.

碩士<br>國立臺灣海洋大學<br>海洋生物研究所<br>95<br>Abstract The forth Nuclear Power Plant built at Gungliao,Taipei county. may pose potential environmental threats to the nearby Yenliao Bay coastal ecosystem due to the thermal discharge, impingement and entrainment in the water of outlet and intake areas after the plant starting to operate in the 2009. Therefore, collecting ecological data in Yenliao Bay before the operation of the 4th Nuclear Power Plant and use it as the baseline information is important for the assessment and monitoring programs for the environmental impact of the 4th Nuclear Power Plant. The purposes of this research are: 1) to demonstrate spatial and a temporal variation of fish community in Yenliao bay; 2) to assemble feeding guilds of dominate fish species using their gut contents; and 3) to construct trophic model of Yenliao bay coastal ecosystem using ECOPATH with ECOSIM. Results showed that species richness, total biomass, and abundance are all larger in the outlet station than the station near intake area. It may be due to the ecotone effect which resulted from the mixed sand and reef seabed near the outlet area and has an isolated reef located nearby. According to stomach contents examined, there were five feeding guilds: 1) benthic feeding fish; 2) piscivorous fish; 3) herbivorous fish; 4) zooplanktivorous fish; 5) polyp-feeding fish in the Yenliao Bay. Among them, benthic feeding fish account for the largest proportion (81.3%). The reef dominant species are almost belonging to the zooplanktivores. The ratio of total primary production to total respiratory is 1.0 which indicates the Yenliao bay was an autotrophic system. It was comprised of 4 trophic levels(4.03). The geometric mean of the trophic transfer efficiencies was 11.1%. The most prominent biological group in terms of biomass and energy flow in the bay was herbivorous zooplankton, its consumption was 983gWW m-2yr-1. Manipulations of the biomass of detritus and benthic feeding fish would have a distinct impact on most compartments. Trophic transfer efficiencies among the 4 trophic levels were 10.7%, 19.3%, and 6.6% respectively. Comparing cycling and ecosystem properties with other coastal ecosystems, it appeared that overall biomass of Yenliao Bay was lower than ones in Chiku and Topony lagoon ecosystems and was equivalent to Kuosheng Bay in the north coast. It is an autotrophic system and has phytoplankton-based food sources, low proportion of the recycled flow, and short food chain. In conclusion, Yenliao Bay is a developing ecosystem which was suffered from disturbances continuously.

Although riparian habitats are important avian breeding areas, few detailed studies of the foraging ecology of birds in such habitats have been reported. I quantified the diet and feeding behavior of 13 species of insectivorous passerines on two study sites in a riparian habitat near Delta Manitoba, during the 1982-1985 breeding seasons. The Manitoba study area was a typical riparian habitat. Vegetation was dominated by a few tree species, dense populations of birds inhabited the area and arthropods were often abundant. Three distinct foraging guilds were identified by discriminant function analysis followed by cluster analysis. One group of birds primarily gleaned for insects in the canopy, another hawked and hovered to obtain prey and the third gleaned and probed to obtain insects below the canopy. Differential use of distinct feeding sites was not important in describing guilds. The foraging behavior of individual species varied more between years than between the two study sites within a year. Two species, Warbling Vireos (Vireo gilvus) and Gray Catbirds (Dumatella carolinensis) belonged to different foraging guilds in different years. Weather conditions, particularly wind and temperature, primarily affected the height at which birds foraged and their use of different feeding maneuvers. There was a high overlap in diet among the bird species because they all frequently fed on the frequently abundant adult midges. Birds in different behavior-defined foraging guilds often had diets as similar to each other as to members of their own foraging guild. When food resources were not abundant, diet overlap among species decreased and diet breadth increased. Although the breadths of feeding behaviors used by individual species generally remained constant despite differing prey availabilities, overlap in behavior among the bird species decreased as anthropod abundance decreased. These findings are consistent with the hypothesis that interspecific competition for food occurred among the riparian birds when food resources were relatively low. Densities of the Manitoba riparian birds may be limited by both food resources and the availability of nesting sites.

碩士<br>國立嘉義大學<br>水產生物學系研究所<br>94<br>Abstract This investigation gathered fish sample by the casting nets way at Haomeiliao Nature Reserve, Chiayi County during May 2004 to April 2005. We colleted 1,316 individuals (64.50 kg as total biomass), belonging to 32 families, 67 species of mangrove fishes. The dominant families we collected here were Carangidae, Mugilidae, Clupeidae and Leiognathidae, and the dominant species were Perch herring (Nematalosa come), Largescale mullet (Liza macrolepis), Blacktip sardinella (Sardinella melanura), Shortnose ponyfish (Leiognathus brevirostris), Tilapia (Oreochromis sp. hybrid), Longarm mullet (Valamugil cunnesius), Blackbarred halfbeak (Hemiramphus dussumieri), Spotted catfish (Arius maculatus) and Hamilton's thryssa (Thryssa hamiltonii). Nowadays, many researchers use feeding guilds as a unit to analysis fish community structure. The most dominant fishes in our investigation belonging to 13 families and 20 species, and then analyse the community structure of the whole year and every season, by the ecostastic software, Primer (v5.2.2). In our investigation we could mainly separate these dominant fishes by clustering for 5 feeding guilds: piscivores, detritivores, crustacivore, zooplanktonivore and omnivores. We found that some fish species may adapt their feeding tendency to seasonal transition. Then, we plotted k-dominance curve in cumulative mode, each for abundance and biomass of dominant fish species; it revealed this researching area is under non- or little-human-infected condition due to the fish ranking biomass is less than ranking abundance. Comparing our analysis of occuring fish species with other 5 mangrove areas of the west seashore of Taiwan (Jhuwei, Hsinfong, Jhunan, Chiku and Dapon-Bay) by the analysis, non-metric multi-dimensional scaling (MDS), we found that the species composition of mangrove fish at west seashore of Taiwan had a pattern of spatial change depending on latitude changing. Finally, most fish species here in our study were carnivores. We suggested that is due to the animal preys were not only variable and abundant, but also vulnerable here. Based on the feeding relations of fishes, a sketchy model of trophic level was constructed in Haomeiliao Nature Reserve, Chiayi County.

Examination of bird assemblages along an environmental gradient which encompasses both climate and habitat change is needed if we are to better understand the potential effects of these changes for avians and the ecological process that depend upon them. Climate change is predicted to have a significant impact on deserts and desert margins, resulting in distributional shifts of entire ecosystems and new community associations. This study explores the probable responses of avian communities to increasing desertification. In general, species richness and numbers of birds in arid zones are low compared to more mesic areas. Different combinations of habitat types and the variety of patches in a landscape influence the diversity and community structures of avians in that landscape. The role of vegetation structure in avian habitat selection in semi-arid areas is dictated by horizontal habitat density as well as vertical structure. Although bird distribution is determined by habitat boundaries, most birds are flexible and can disperse across small habitat barriers. The hypothesis tested, was that bird species assemblages along an aridity gradient are affected primarily by rainfall and secondarily by habitat type. Assessing the impacts of rainfall and habitat on bird variables, such as species richness, abundance, diversity, biomass, and life history traits, were the objectives of the study. An east-west aridity gradient of 300 mm, stretching over 370 km, was chosen in central Namibia for the study area. The climate is harsh with localised rain and considerable daily fluctuations in temperature. Grasses, and trees and shrubs up to 7 m in height are the co-dominant life-forms. Surveys were conducted over three years; one winter and one summer survey in each year. Rainfall, seasons and vegetation height were recorded as environmental variables. Three structurally different habitat types were selected for stratified sampling: open areas, rivers and thickets. Open areas were dominated by grass; river refers to ephemeral dry river lines with mature trees; and thickets comprise woody shrubs and trees. At each site, the same three habitats were used for bird sampling, resulting in 15 sample units. Sampling took place on 51 discontinuous line transects of 1km in length and without a width limit. Univariate analyses included ANOVA and t-tests. Multivariate analyses consisted of cluster analysis, MRPP tests, indicator analysis, Shannon diversity index and NMS ordinations. NMS bi-plots were used to define avian community structures responding to aridity, habitat, migration and life history traits. The results showed that bird species richness, abundance, and diversity remained relatively constant across the aridity gradient, until they declined significantly once a certain aridity threshold was crossed at the most arid site. There were significantly more bird species and individual birds at the wetter sites than at the drier sites. Rivers contained more birds than thickened or open habitat types, suggesting the importance of riparian habitat types for maintaining avian diversity. The three more mesic sites included higher numbers of species from the nesting and feeding guilds, regardless of habitat type, than the two more arid sites. The aridity threshold had a significant effect on bird community structures: more migrant and nomadic species, and omnivore and insectivore species persisted in very arid conditions. From the results it was predicted that climate change will cause avian species to undergo range shifts from west to east, resulting in community composition changes and a reduction in diversity. Life history traits affect the adaptive capabilities of bird species and it is predicted that nomadism, flexibility in diet, and adaptability of nesting requirements will contribute to species persistence in the drier conditions predicted under current climate change scenarios. Dry river lines will act as refugia for avian diversity, but crucial habitat types that currently contain less diversity are also important for maintaining unique avian assemblages.<br>MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

This dissertation addresses large-scale trends in composition, density, taxonomic and functional diversity in deep-sea benthic polychaete communities in the Gulf of Mexico (GoM). The study includes samples from two major sampling programs: the Deep Gulf of Mexico Benthos (DGoMB) program (2000–2002) (51 stations, 200-3700 m) and the SIGSBEE program (Universidad Nacional Autónoma de México), 2008-2010 (27 stations on the Sigsbee Abyssal Plain). Polychaete density decreased exponentially with depth. Alpha diversity did not show a mid-depth maximum and reached its peak near the Mississippi trough. Feeding guild diversity was also highest in the Mississippi trough. The environmental parameters that determine diversity and density of polychaete assemblages and species distribution ranges were examined. Depth, export flux of particulate organic carbon (POC), percent sand and silt were the best predictors of heterogeneity of polychaetes in the GoM. We performed an ecological niche modeling analysis (ENM) based on ‘presence-only’ data of four cosmopolitan species belonging to the Cirratulidae and Spionidae in the GoM. The GoM, being a semi-enclosed ocean basin, offers complex topographic features and hydrographic processes. Comparisons of the overall polychaete diversity and richness patterns from this study for this region indicate a strong geographic variation with increasing depth and distance from the shore. Additionally, the environmental gradients observed play a major role in shaping the spatial distribution of polychaete communities in this region.