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Distribuição e abundância de aves em relação ao uso da terra na bacia do rio Passa-Cinco, estado de São Paulo, Brasil; Distribution and abundance of birds in relation to land use in Passa-Cinco river basin, state of São Paulo, Brazil

Penteado, Marli
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 12/04/2006 PT
Relevância na Pesquisa
36.38%
Paisagens em mosaico, compostas por fragmentos de vegetação natural e habitats implantados, estão se tornando comuns em todo mundo, devido principalmente à agricultura. Por esta razão, os inventários de vida silvestre e os programas de conservação devem considerar não somente habitats prístinos, mas também agroecossistemas. Este estudo é parte de uma pesquisa multitaxa realizada na mesma bacia hidrográfica. Seus objetivos principais foram determinar a riqueza e abundância de aves em diferentes elementos de uma paisagem agrícola usando a Bacia do rio Passa-Cinco (entre as latitudes 22º05`e 22º30`S e as longitudes 47º30`e 47º50`W) como modelo, e também testar a eficácia do método de ponto para amostragem de aves em habitats antrópicos. Para tanto, foram utilizados múltiplos níveis de informação de variáveis de habitat à variáveis ambientais e análises estatísticas multivariadas. Foram registradas 224 espécies de aves em toda a bacia. As florestas nativas apresentaram maior riqueza de espécies (164) e as pastagens a maior abundância de indivíduos. Os fragmentos de floresta nativa apresentaram um padrão distinto dos outros elementos da paisagem, quando se considera a composição específica e abundância nas análises de escalonamento multidimensional. As categorias tróficas apresentaram diferentes padrões de distribuição e abundância em relação aos diferentes elementos da paisagem. Habitats mais estruturados...

Modelos teóricos de distribuição de abundância das espécies para caracterização da diversidade biológica e a utilização de diferentes medidas de abundância; Theoretical models of species abundance distribution to characterize the biological diversity and the use of different measures of abundance

Condé, Paula Alves
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 23/08/2012 PT
Relevância na Pesquisa
36.48%
As distribuições de abundância das espécies (SADs) são consideradas uma maneira informativa e sintética de descrever a diversidade biológica, e revelam um dos padrões mais bem estabelecidos da ecologia, que é a predominância de espécies raras nas comunidades biológicas. A generalidade deste padrão o torna relevante para a análise de outros parâmetros das comunidades. Além disso, ele levou ao desenvolvimento dos modelos teóricos de SAD. Os modelos estatísticos de SAD, por sua vez, passaram a ocupar um papel central na biologia, como principio empírico que sustenta várias teorias ecológicas. Preston sugeriu em 1948 que as SADs das comunidades naturais teriam uma distribuição aproximadamente Lognormal, porém apareciam truncadas devido ao efeito do tamanho amostral, cuja forma real só seria revelada, portanto, em amostras grandes. Esta ideia vai de encontro à propriedade estatística da consistência, que implica que o acúmulo de evidência causado pelo aumento do tamanho amostral favorece a aproximação ao modelo verdadeiro, bem como às estimativas de seus parâmetros. Além do efeito do tamanho amostral, os padrões de distribuição de abundância podem diferir dependendo da medida de abundância utilizada. Estudos sugerem que a biomassa seria uma medida de abundância mais adequada para revelar a distribuição subjacente de uma comunidade biológica em amostras ou escalas menores (differential veiling). Neste contexto...

Abundance and ecologic distribution of the shrimp Rimapenaeus constrictus (Crustacea : Penaeidae) on the northern coast of São Paulo State, Brazil

Costa, R. C.; Fransozo, A.
Fonte: Taylor & Francis Ltd Publicador: Taylor & Francis Ltd
Tipo: Artigo de Revista Científica Formato: 901-912
ENG
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The abundance and ecologic distribution of the shrimp R. constrictus were compared among three different embayments within the northern coast of São Paulo State (23degreesS, 45degreesW); i.e. Mar Virado (MV), Ubatuba (UBA) and Ubatumirim (UBM). Key environmental factors were monitored for a better understanding of the distributional patterns of this species, namely temperature, salinity, depth, organic matter content and texture of sediments. In each bay, six transects were delimited, four parallel to the coastline and the other two in areas adjacent to rocky shores. Monthly samples were taken over a 2-year period (1998 and 1999), using a shrimp fishing boat equipped with double-rig nets. Abundance data were treated separately according to environmental characteristics. A total of 4978 specimens was obtained; 921 at MV, 1948 at UBA and 2109 at UBM. The spatial distribution of R. constrictus differed among bays. Higher abundance values were recorded at areas where silt and clay comprised less than 70% of the sediment. A more diversified sediment at UBM and UBA apparently favours the establishment of this species in the region. Its abundance also followed a seasonal trend, higher during spring and summer when intrusions of cold South Atlantic Coastal Waters (SACW) are frequent...

Temporal changes of abundance, biomass and production of copepod community in a shallow temperate estuary (Ria de Aveiro, Portugal)

Leandro, S. M.; Morgado, F.; Pereira, F.; Queiroga, H.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
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The present study reports on temporal changes of abundance, biomass and secondary production of the copepod community of Ria de Aveiro (Portugal). Zooplankton sampling and hydrological measurements (salinity, temperature, chlorophyll a and nutrients concentrations) were conducted at four occasions (June 2000, September 2000, December 2000 and March 2001), at 6 sampling stations and during ebb and flood. The contribution of copepods (from nauplius to adults) to the total abundance and biomass of the zooplankton community of Ria de Aveiro (Portugal) was equal to 63.6% and 62.0%, respectively (annual average). The estimate of nauplius abundance given by two zooplankton nets with different meshes was significantly different (P < 0.001) with the 64 μm net collecting 13.9 times more than the 125 μm one. No significant differences were found for copepodites and adults. The abundance of all development stages (except adults) was positively correlated (P < 0.05) with salinity and temperature. The seasonal patterns of abundance and biomass were similar to those found in other temperate coastal waters. Mean daily secondary production rate (mean ± SE) estimated by the Huntley and Lopez growth model [Huntley, M.E., Lopez, M.D.G., 1992. Temperature-dependent production of marine copepods: a global synthesis. American Naturalist 140...

Larval abundance patterns of Carcinus-Maenas (Decapoda, Brachyura) in Canal de Mira (Ria de Aveiro, Portugal)

Queiroga, H.; Costlow, J. D.; Moreira, M. H.
Fonte: Inter Research Publicador: Inter Research
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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Larval stages of Carcinus maenas (L.) were intensively sampled in the Canal de Mira (Ria de Aveiro, Portugal) during 2 lunar months: February 12 to March 11 and May 9 to June 7, 1990. Each sampling period included fifteen 25 h fixed-station sampling cycles beginning at intervals of 4 tide cycles. Within each 25 h sampling cycle, plankton samples were collected hourly at several depths using a pump. Analysis of the data from these sampling periods indicated tidal and diel cycles of abundance of first stage C. maenas larvae. A semilunar component was also identified. These patterns were expressed as peaks of abundance during ebb tides, with highest peaks during nocturnal neap ebb tides around the first and last quarters of the moon. Peaks of nocturnal abundance could occur at any time during the night but consistently followed high water. In contrast, megalopae were present in the samples primarily during nocturnal flood tides. Intermediate zoeal stages of C. maenas were not collected. As indicated by an analysis of variance, the main effects of phases of the tide and day on the abundance of first zoeae and megalopae were significant (p < 0.05). These results provide evidence that a component with semilunar periodicity is associated with the release of C. maenas larvae. That the release activity occurs well after sunset is also an additional interesting feature of these observations...

Spatial scaling of species abundance distributions

Borda-de-Água, Luís; Borges, Paulo A. V.; Hubbell, Stephen P.; Pereira, Henrique M.
Fonte: Wiley-Blackwell Publicador: Wiley-Blackwell
Tipo: Artigo de Revista Científica
Publicado em /06/2012 ENG
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Copyright © 2012 The Authors. Ecography © 2012 Nordic Society Oikos.; Species abundance distributions are an essential tool in describing the biodiversity of ecological communities. We now know that their shape changes as a function of the size of area sampled. Here we analyze the scaling properties of species abundance distributions by using the moments of the logarithmically transformed number of individuals. We find that the moments as a function of area size are well fitted by power laws and we use this pattern to estimate the species abundance distribution for areas larger than those sampled. To reconstruct the species abundance distribution from its moments, we use discrete Tchebichef polynomials. We exemplify the method with data on tree and shrub species from a 50 ha plot of tropical rain forest on Barro Colorado Island, Panama. We test the method within the 50 ha plot, and then we extrapolate the species abundance distribution for areas up to 5 km2. Our results project that for areas above 50 ha the species abundance distributions have a bimodal shape with a local maximum occurring for the singleton classes and that this maximum increases with sampled area size.

Variations in the abundance of three Parulidae species in the southern portion of the Brazilian Atlantic Forest, state of Paraná

Santana,Cássius R.; Bochio,Gabriela M.; Anjos,Luiz dos
Fonte: Academia Brasileira de Ciências Publicador: Academia Brasileira de Ciências
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2012 EN
Relevância na Pesquisa
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We evaluated the distribution of abundance of three species of warblers in the southern portion of the Brazilian Atlantic Forest (BAF): Tropical Parula (Parula pitiayumi), the Golden-Crowned Warbler (Basileuterus culicivorus) and the White-Rimmed Warbler (Basileuterus leucoblepharus). Three types of forests comprise this region of the Atlantic Forest: seasonal semi-deciduous forest (SF), mixed rain forest (MF) and dense rain forest (DF). These forest types occur at different elevations: SF ranging from 200 to 800 m, MF ranging from 800 to 1,200 m and DF ranging from sea level up to 2,000 m. We used point counts in fifteen study areas distributed in the three forest types. The White-Rimmed Warbler and the Tropical Parula had higher abundances in MF, and their abundance was positively correlated with the elevation. The Golden-Crowned Warbler did not present a significant difference in abundance among the forest types, and no correlation between abundance and elevation was found. We suggest that the difference in the occupancy of the forest strata by the Golden-Crowned Warbler is because this species is more generalist and thus less sensitive to variations in the vegetation structure among the forests types when compared to the other two warbler species.

Splendid oddness: revisiting the curious trophic relationships of South American Pleistocene mammals and their abundance

FARIÑA,RICHARD A.; CZERWONOGORA,ADA; GIACOMO,MARIANA DI
Fonte: Academia Brasileira de Ciências Publicador: Academia Brasileira de Ciências
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2014 EN
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The South American Pleistocene mammal fauna includes great-sized animals that have intrigued scientists for over two centuries. Here we intend to update the knowledge on its palaeoecology and provide new evidence regarding two approaches: energetics and population density and relative abundance of fossils per taxa. To determine whether an imbalance exists, population density models were applied to several South American fossil faunas and the results compared to those that best describe the palaeoecology of African faunas. The results on the abundance study for Uruguay and the province of Buenos Aires during the Lujanian stage/age reveal that bulk-feeding ground sloths (Lestodon and Glossotherium) were more represented in the first territory, while the more selective Scelidotherium and Megatherium were more abundant in the second. Although the obtained values were corrected to avoid size-related taphonomic biases, linear regressions of abundance vs. body mass plots did not fit the expected either for first or second consumers. South American Pleistocene faunas behave differently from what models suggest they should. Changes in sea level and available area could account for these differences; the possibility of a floodplain in the area then emerged could explain seasonal changes...

Abundance distribution of common and rare plant species of Brazilian savannas along a seasonality gradient

Silva,Igor Aurélio; Cianciaruso,Marcus Vinicius; Batalha,Marco Antônio
Fonte: Sociedade Botânica do Brasil Publicador: Sociedade Botânica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2010 EN
Relevância na Pesquisa
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We examined the species abundance distribution (SAD) of plant communities in: (1) a wet grassland, waterlogged throughout most of the year; (2) a seasonal savanna, with an annual dry season; and (3) a hyperseasonal savanna, with alternating drought and waterlogging over the year. We searched for differences in the abundance distributions of all species, as well as of the common and rare species. We tested whether the SADs fitted the lognormal, log-series, power fraction, and random assortment models. We found that environmental constraints may reduce the evenness of plant communities and change the SADs in savannas. We observed a lognormal abundance distribution in the wet grassland and a random abundance distribution in the hyperseasonal cerrado. The SAD of the seasonal savanna did not follow any model. The common species in the three communities were better fitted by the lognormal model. The rare species in the wet grassland and the hyperseasonal cerrado were better fitted by the random assortment model. The SAD of the rare species of the seasonal savanna did not follow any model. Seasonality seems to modify the lognormal distribution of the overall plant community, generating abundance distributions indistinguishable from random. However...

Helminth communities in three sympatric rodents from the Brazilian Atlantic Forest: contrasting biomass and numerical abundance

Simões,RO.; Maldonado-Júnior,A.; Luque,JL.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2012 EN
Relevância na Pesquisa
36.41%
The study of parasite body size is an important approach to understand the different patterns of helminth community structure, once it is usually analysed using only numerical descriptors which do not capture size heterogeneity among parasite species. In the present study, we compared the pattern in the helminth community of three sympatric wild rodent species Akodon cursor, A. montensis and Oligoryzomys nigripes using numerical abundance and biomass approaches. The cestode Rodentolepis akodontis was the worm with highest biomass in the three rodents. The trichostrongylid Stilestrongylus lanfrediae presented highest biomass in O. nigripes and represented 70% of the total numeric abundance of parasites. Interestingly, for Akodon spp. the species with more biomass represented less than 10% of the total numerical abundance. Parasites with the higher numeric abundance do not have the largest body size. Although the biomass pattern is different from numeric abundance, this difference does not influence in the helminth distribution community among the three sympatric hosts. The status change of a helminth species within the community due to its volumetric dominance might justify a new approach since parasites belonging to different taxa obtain resources from the host in different ways.

Calibrating abundance indices with population size estimators of red back salamanders (Plethodon cinereus) in a New England Forest.

Siddig, Ahmed Ali; Ellison, Aaron M.; Jackson, Scott
Fonte: PeerJ Inc. Publicador: PeerJ Inc.
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
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Herpetologists and conservation biologists frequently use convenient and cost-effective, but less accurate, abundance indices (e.g., number of individuals collected under artificial cover boards or during natural objects surveys) in lieu of more accurate, but costly and destructive, population size estimators to detect and monitor size, state, and trends of amphibian populations. Although there are advantages and disadvantages to each approach, reliable use of abundance indices requires that they be calibrated with accurate population estimators. Such calibrations, however, are rare. The red back salamander, Plethodon cinereus, is an ecologically useful indicator species of forest dynamics, and accurate calibration of indices of salamander abundance could increase the reliability of abundance indices used in monitoring programs. We calibrated abundance indices derived from surveys of P. cinereus under artificial cover boards or natural objects with a more accurate estimator of their population size in a New England forest. Average densities/m2 and capture probabilities of P. cinereus under natural objects or cover boards in independent, replicate sites at the Harvard Forest (Petersham, Massachusetts, USA) were similar in stands dominated by Tsuga canadensis (eastern hemlock) and deciduous hardwood species (predominantly Quercus rubra [red oak] and Acer rubrum [red maple]). The abundance index based on salamanders surveyed under natural objects was significantly associated with density estimates of P. cinereus derived from depletion (removal) surveys...

Calibrating abundance indices with population size estimators of red back salamanders (Plethodon cinereus) in a New England forest

Siddig, Ahmed A.; Ellison, Aaron M.; Jackson, Scott
Fonte: PeerJ Inc. Publicador: PeerJ Inc.
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
36.49%
Herpetologists and conservation biologists frequently use convenient and cost-effective, but less accurate, abundance indices (e.g., number of individuals collected under artificial cover boards or during natural objects surveys) in lieu of more accurate, but costly and destructive, population size estimators to detect and monitor size, state, and trends of amphibian populations. Although there are advantages and disadvantages to each approach, reliable use of abundance indices requires that they be calibrated with accurate population estimators. Such calibrations, however, are rare. The red back salamander, Plethodon cinereus, is an ecologically useful indicator species of forest dynamics, and accurate calibration of indices of salamander abundance could increase the reliability of abundance indices used in monitoring programs. We calibrated abundance indices derived from surveys of P. cinereus under artificial cover boards or natural objects with a more accurate estimator of their population size in a New England forest. Average densities/m2 and capture probabilities of P. cinereus under natural objects or cover boards in independent, replicate sites at the Harvard Forest (Petersham, Massachusetts, USA) were similar in stands dominated by Tsuga canadensis (eastern hemlock) and deciduous hardwood species (predominantly Quercus rubra [red oak] and Acer rubrum [red maple]). The abundance index based on salamanders surveyed under natural objects was significantly associated with density estimates of P. cinereus derived from depletion (removal) surveys...

Habitat, distribution, and abundance of the commercial octopus (octopus insularis) in a tropical oceanic island, Brazil: Information for management of an artisanal fishery inside a marine protected area

Leite, Tatiana Silva; Haimovici, Manuel; Mather, Jennifer; Oliveira, Jorge Eduardo Lins
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.38%
The spatial distribution, abundance and habitat of a population of a shallow-water octopus, Octopus insularis, subject to some fishery pressure,was studied in the Fernando de Noronha Archipelago, a marine protected area off northeastern Brazil. Three techniqueswere used: visual censuses in fixed quadrants and in roving-diver and catch per unit of effort (CPUE) of the commercial fishery.We had two hypotheses, that the species had a nonrandom distribution, related to substrate and body size, and that relative abundance outside the national parkwould be lower than within, possibly due to fishery pressure.We found a patchy distribution over all, with octopuses almost confined to substrates with a large proportion of hard surfaces. Therewere seasonal and depth effects on distribution of the very small octopuses found mainly in shallow water (intertidal to 5m depth) during the dry season. Abundance was similar inside and outside of the national park, which suggests that the octopus fishery is not a threat to the abundance of O. insularis at this present level.

Spatial scale and abundance patterns of large fish communities in freshwater marshes of the Florida Everglades

Chick, John H.; Ruetz, Carl R.; Trexler, Joel C.
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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Anthropogenic habitat alterations and water-management practices have imposed an artificial spatial scale onto the once contiguous freshwater marshes of the Florida Everglades. To gain insight into how these changes may affect biotic communities, we examined whether variation in the abundance and community structure of large fishes (SL . 8 cm) in Everglades marshes varied more at regional or intraregional scales, and whether this variation was related to hydroperiod, water depth, floating mat volume, and vegetation density. From October 1997 to October 2002, we used an airboat electrofisher to sample large fishes at sites within three regions of the Everglades. Each of these regions is subject to unique watermanagement schedules. Dry-down events (water depth , 10 cm) occurred at several sites during spring in 1999, 2000, 2001, and 2002. The 2001 dry-down event was the most severe and widespread. Abundance of several fishes decreased significantly through time, and the number of days post-dry-down covaried significantly with abundance for several species. Processes operating at the regional scale appear to play important roles in regulating large fishes. The most pronounced patterns in abundance and community structure occurred at the regional scale...

Have recent mass mortalities of the sardine Sardinops sagax facilitated an expansion in the distribution and abundance of the anchovy Engraulis australis in South Australia?

Ward, T.; Hoedt, F.; McLeay, L.; Dimmlich, W.; Jackson, G.; Rogers, P.; Jones, K.
Fonte: Inter-research Publicador: Inter-research
Tipo: Artigo de Revista Científica
Publicado em //2001 EN
Relevância na Pesquisa
36.41%
This paper examines the hypotheses (1) that Sardinops sagax and Engraulis australis are spatially segregated and do not interact directly, and (2) that recent mass mortalities of S. sagax have facilitated an expansion in the distribution and abundance of E. australis. In South Australian waters, S. sagax and E. australis both spawn during summer and autumn. Eggs and larvae of both species occur over the continental shelf, and are abundant in areas where upwelling occurs (e.g. off the Coffin Bay Peninsula and the western tip of Kangaroo Island) and frontal systems form (e.g. in Investigator Strait and the entrance of Spencer Gulf). After the mass- mortality events in 1995 and 1998, eggs and larvae of S. sagax were confined mainly to these areas, and estimates of the total abundance of S. sagax eggs and larvae in South Australian waters fell by between 48 and 83% respectively. Between 1996 and 1999, densities of E. australis eggs and larvae increased in both key spawning areas and the central and eastern Great Australian Bight, and total abundance of eggs and larvae increased by over 215 and 285% respectively. These results indicate that (1) S. sagax and E. australis are not spatially segregated and may interact directly, and (2) the mass mortalities of S. sagax may have facilitated an expansion in the distribution and abundance of E. australis. Hence...

Abundance of two Dendrocincla woodcreepers (aves: Dendrocolaptidae) in relation to forest structure in Central Amazonia

Cintra,Renato; Maruoka,Adrianny Erika; Naka,Luciano Nicolas
Fonte: Instituto Nacional de Pesquisas da Amazônia Publicador: Instituto Nacional de Pesquisas da Amazônia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2006 EN
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Few studies have been conducted to verify how the structure of the forest affects the occurence and abundance of neotropical birds. Our research was undertaken between January 2002 and July 2004 at the Reserva Ducke, near Manaus (02º55',03º01'S; 59º53',59º59'W) in central Amazonia, to verify how the forest structure affects the occurrence and abundance of two bird species: the Plain-brown Woodcreeper Dendrocincla fuliginosa and the White-chinned Woodcreeper Dendrocincla merula. Bird species occurrence was recorded using lines of 20 mist-nets (one sample unit), along 51 1-km transects distributed along 9 pararel 8 km trails covering an area of 6400 ha. Along these transects, we placed 50 x 50m plots where we recorded forest structure components (tree abundance, canopy openness, leaf litter, standing dead trees, logs, proximity to streams, and altitude). We then related these variables to bird occurence and abundance using multiple logistic and multiple linear regression models, respectively. We found that D. fuliginosa frequently used plateau areas; being more abundant in areas with more trees. On the other hand, D. merula occurred more frequently and was more abundant in areas with low tree abundance. Our results suggest that although both species overlap in the reserve (both were recorded in at least 68% of the sampled sites)...

The importance of pollinator generalization and abundance for the reproductive success of a generalist plant

Maldonado, María Belén; Lomascolo, Silvia Beatriz; Vazquez, Diego P.
Fonte: Public Library Science Publicador: Public Library Science
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
ENG
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Previous studies have examined separately how pollinator generalization and abundance influence plant reproductive success, but none so far has evaluated simultaneously the relative importance of these pollinator attributes. Here we evaluated the extent to which pollinator generalization and abundance influence plant reproductive success per visit and at the population level on a generalist plant, Opuntia sulphurea (Cactaceae). We used field experiments and path analysis to evaluate whether the per-visit effect is determined by the pollinator?s degree of generalization, and whether the population level effect (pollinator impact) is determined by the pollinator?s degree of generalization and abundance. Based on the models we tested, we concluded that the per-visit effect of a pollinator on plant reproduction was not determined by the pollinators? degree of generalization, while the population-level impact of a pollinator on plant reproduction was mainly determined by the pollinators? degree of generalization. Thus, generalist pollinators have the greatest species impact on pollination and reproductive success of O. sulphurea. According to our analysis this greatest impact of generalist pollinators may be partly explained by pollinator abundance. However...

Small-scale estimation of relative abundance for the coastal spotted dolphins (Stenella attenuata) in Costa Rica: the effect of habitat and seasonality

May-Collado,Laura J; Forcada,Jaume
Fonte: Revista de Biología Tropical Publicador: Revista de Biología Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2012 EN
Relevância na Pesquisa
36.41%
The coastal spotted dolphin (Stenella attenuata graffmani) is one of the most common species of dolphin in inshore Pacific waters of Costa Rica. We conducted surveys in protected waters of the Papagayo Gulf, Costa Rica, to determine relative abundance of dolphins in relation to environmental variables. We used Generalized Additive Models to investigate the influence of a particular set of environmental factors and determine inter-annual trends in relative abundance. School sizes ranged from 1 to 50 individuals ( mean 9.95, SD=10.28). The number of dolphins increased linearly with water depth and transparency, and non-linearly with the dissolved oxygen concentration. High variability in the relative abundance occurred during the dry season (January-April). A previous study on this population found that high number of groups are involved in foraging activities during the dry season. Seasonal changes in relative abundance probably are associated with food availability, a variable that we did not measure. Understanding local resident populations may have important implications for conservation and management strategies. Large-scale studies may overlook variables affecting the abundance of local resident populations that may be detected with studies on a smaller scale such as this one.

Species richness and relative species abundance of Nymphalidae (Lepidoptera) in three forests with different perturbations in the North-Central Caribbean of Costa Rica

Stephen,Carolyn; Sánchez,Ragde
Fonte: Revista de Biología Tropical Publicador: Revista de Biología Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2014 EN
Relevância na Pesquisa
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Measurements of species richness and species abundance can have important implications for regulations and conservation. This study investigated species richness and abundance of butterflies in the family Nymphalidae at undisturbed, and disturbed habitats in Tirimbina Biological Reserve and Nogal Private Reserve, Sarapiquí, Costa Rica. Traps baited with rotten banana were placed in the canopy and the understory of three habitats: within mature forest, at a river/forest border, and at a banana plantation/forest border. In total, 71 species and 487 individuals were caught and identified during May and June 2011 and May 2013. Species richness and species abundance were found to increase significantly at perturbed habitats (p<0.0001, p<0.0001, respectively). The edge effect, in which species richness and abundance increase due to greater complementary resources from different habitats, could be one possible explanation for increased species richness and abundance. Rev. Biol. Trop. 62 (3): 919-928. Epub 2014 September 01.

Abundance and diversity of soil mites (acari) along a gradient of land use types in Taita Taveta, Kenya

Maribie,C.W.; Nyamasyo,G.H.N.; Ndegwa,P.N.; Lagerlöf,J.; Gikungu,M
Fonte: Universidad Autónoma de Yucatán, Facultad de Medicina Veterinaria Publicador: Universidad Autónoma de Yucatán, Facultad de Medicina Veterinaria
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 EN
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The abundance and diversity of soil mites was monitored along a gradient of land use types (LUTs) during the wet seasons in soils of Taita Taveta, Kenya. Sampling of mites from soils was carried out in eight LUTs which included maize-based system (Zea mays), coffee (Coffea Arábica), horticulture, napier grass (Pennisetum purpureum), fallow, pine (Pinus patula), cypress (Cypressus lusitanica), natural forest. LUT significantly influenced abundance, richness and diversity of the soil mites. During the short rains the diversity of soil mites increased in the order napier ,maize-based system, horticulture, coffee, fallow, natural forest, pine forest, cypress plantation while the long rains season abundance increased in the order maize-based system, coffee, horticulture, napier, natural forest, fallow, pine forest, cypress forest. Higher abundance, richness and diversity of the mites was observed in the less disturbed forest ecosystems unlike the agro-ecosystems, which are often disturbed with intensive cultivation A total of 37 families were recorded with 20 oribatid families, 10 mesostigmatid families and 7 prostigmatid families. The families that ranked highest in abundance across the LUT were Scheloribatidae, Oppidae (Oribatida) and Rhodacaridae (Mesostigmata). Land use type influenced significantly (P<0.05) the abundance and diversity of soil mites where intensification lowered the diversity and abundances resulting in less complex mites community structures.