Habitat amount hypothesis and passive sampling explain mammal species composition in Amazonian river islands

Biotropica ◽  
2019 ◽  
Vol 51 (1) ◽  
pp. 84-92 ◽  
Author(s):  
Rafael M. Rabelo ◽  
Susan Aragón ◽  
Júlio César Bicca-Marques ◽  
Bruce W. Nelson
2020 ◽  
Vol 18 (7) ◽  
pp. 376-383 ◽  
Author(s):  
R Travis Belote ◽  
Søren Faurby ◽  
Angela Brennan ◽  
Neil H Carter ◽  
Matthew S Dietz ◽  
...  

2010 ◽  
Vol 16 (1) ◽  
pp. 36 ◽  
Author(s):  
A. J. Buckmaster ◽  
W. S. Osborne ◽  
N. Webb

Urban development can alter species composition and diversity within an area through biotic homogenization, the introduction of exotic species, and localized extinctions of native species. In this study we examined the composition and diversity of small terrestrial mammals within nature reserves surrounded by urban landscapes and compared this with previous surveys of these reserves and nearby non-urban reserves with similar vegetative and geomorphological characteristics. A combination of live trapping and indirect detection techniques was employed in eight reserves in the Australian Capital Territory and surrounding New South Wales to determine current species composition. Compared with previous studies and the non-urban reserves, the urban reserves appear to have lost two-thirds of their native terrestrial small mammal species in the past 26 years. Exotic species were present in all urban reserves, but were only associated with areas characterized by human-induced disturbance in non-urban reserves. Possible causes of this disparity in native species diversity between urban and non-urban reserves are discussed.


2019 ◽  
Vol 12 ◽  
pp. 194008291987037 ◽  
Author(s):  
Antonia Nyamukuru ◽  
John-Arvid Grytnes ◽  
John R. S. Tabuti ◽  
Ørjan Totland

Protected areas generally occur within a matrix of intensively human-modified landscapes. As a way to maintain the biodiversity in these areas, enclosure by fencing is often preferred. This strategy, however, is costly and little is known about the effectiveness of the alternative of unfenced borders on the vegetation and fauna. The objectives of this study are to assess whether there is a distinct difference in biodiversity and composition of plants and mammals between the protected Lake Mburo National Park and the adjacent ranchlands across an unfenced border and to determine the associations between vegetation and faunal species over the same border. We recorded herbaceous vegetation, woody vegetation, and mammal species composition in plots 300 to 500 m away from the border both inside the protected area and in the adjacent ranchlands. The species composition of herbs and mammals in the protected area differ from the adjacent ranchlands, but there is no difference for trees and shrubs. After accounting for land-use type, distance from the border did not significantly account for any additional variation. We also find a correlation between the species composition of vegetation and fauna. Our results suggest that unfenced borders around protected areas create a clear effect.


2019 ◽  
Vol 59 ◽  
pp. e20195942 ◽  
Author(s):  
Átilla Colombo Ferreguetti ◽  
Isadora Cristina Motta Lessa ◽  
Emerson Monteiro Vieira ◽  
André Almeida Cunha ◽  
Helena Godoy Bergallo

The Cerrado is the second largest Brazilian biome and only 2.8% is represented by protected areas. Considering the relevance of the Cerrado and Conservation Units in preserving the mammalian diversity, we provided the first assessment of the diversity of medium- and large-sized mammal species in the Chapada dos Veadeiros National Park (CVNP) and surroundings. We tested the effectiveness of the CVNP by assessing the difference in species composition within the park and its surroundings. We sampled CVNP in the rainy (October-December 2013) and dry seasons (March-June 2014) in order to characterize the seasonality within the community. We selected 36 sampling sites to evaluate the composition of the medium and large mammals in the CVNP and its surroundings, 18 in the CVNP and 18 in the park surroundings. We ordered mammalian composition and frequency of individuals data by using a Non-metric Multidimensional Scaling analysis (NMDS). We assessed the effect of season (dry and rainy seasons) and locality (within the CVNP and surroundings) on mammalian species richness with a two-way analysis of variance (Two-way ANOVA). We recorded 23 species, 13 within the CVNP and 17 species in its surroundings. Composition and frequency of records differed between dry and rainy seasons, with higher richness in the rainy season. Species’ composition and the frequency of records were also different between within the CVNP and its surroundings, with higher richness in the surroundings. These results provide information for the increase of the knowledge of mammalian ecology but also is useful as a tool for future strategies to the conservation of these species. More attention should be given to the monitoring of these species in the long term because this area still harbor some viable populations.


2014 ◽  
Vol 14 (4) ◽  
Author(s):  
Renan Maestri ◽  
Daniel Galiano ◽  
Bruno Busnello Kubiak ◽  
Jorge Reppold Marinho

Small land mammals possess features that significantly influence the dynamics of ecosystems and participate in various levels of the food web. In the Brazilian Atlantic Forest the richness of these animals is high, which makes them even more ecologically and numerically relevant in this environment. In this context, we investigated the species composition of small mammals in an unexplored area of southern Brazil, and compared the species composition of this area with other Atlantic Forest regions in order to understand how this community is related to others. The study area was located in an interior Atlantic forest formation, at a transition region between deciduous and Araucaria forests. Small mammals were captured at five collection points using pitfall traps. We compared the species composition found in our studied area with the composition of other 11 studies in different regions by a cluster analysis, and we investigated the presence of spatial autocorrelation between communities with a Mantel test. We recorded 779 individuals from 21 species of small rodents (15 species) and marsupials (six species) during the 13 months of the collection period. This richness was high compared to other studies conducted in the Atlantic Forest formations near to coastline and in interior forest formations. This may be a result of the conditions provided by this transition area (deciduous and Araucaria forests), where could be found elements of the both forests formations, which probably allows the establishment of small mammal species from both forest types. Despite differences in sampling effort of the studies, our results suggest that the interior forest formations may harbor a number of species comparable to the formations near the coast. The species composition of this area was similar to those found in other interior forest formations with the same phytophysiognomy characteristics and at nearby regions, and it was less similar to the distant formations located in southeastern and northeastern Brazil and nearby to the coastline. This can be a result of both the spatial autocorrelation (i.e. more nearby communities tend to have more similar species composition) and the differences of forest characteristics among regions.


2020 ◽  
Author(s):  
Santiago Saura

AbstractThe Habitat Amount Hypothesis (HAH) predicts that species richness, abundance or occurrence in a habitat site increases with the amount of habitat in the ‘local landscape’ defined by an appropriate distance around the site, with no distinct effects of the size of the habitat patch in which the site is located. It has been stated that a consequence of the HAH, if supported, would be that it is unnecessary to consider habitat configuration to predict or manage biodiversity patterns, and that conservation strategies should focus on habitat amount regardless of fragmentation. Here, I assume that the HAH holds and apply the HAH predictions to all habitat sites over entire landscapes that have the same amount of habitat but differ in habitat configuration. By doing so, I show that the HAH actually implies clearly negative effects of habitat fragmentation, and of other spatial configuration changes, on species richness, abundance or occurrence in all or many of the habitat sites in the landscape, and that these habitat configuration effects are distinct from those of habitat amount in the landscape. I further show that, contrary to current interpretations, the HAH is compatible with a steeper slope of the species-area relationship for fragmented than for continuous habitat, and with higher species richness or abundance for a single large patch than for several small patches with the same total area (SLOSS). This suggests the need to revise the ways in which the HAH has been interpreted and can be actually tested. The misinterpretation of the HAH has arisen from confounding and overlooking the differences in the spatial scales involved: the individual habitat site at which the HAH gives predictions, the local landscape around an individual site, and the landscapes or regions (with multiple habitat sites and different local landscapes) that need to be analysed and managed. The HAH has been erroneously viewed as negating or diminishing the relevance of fragmentation effects, while it actually supports the importance of habitat configuration for biodiversity. I conclude that, even in the cases where the HAH holds, habitat fragmentation and configuration are important for understanding and managing species distributions in the landscape.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4531 ◽  
Author(s):  
Rodolfo Jaffé ◽  
Xavier Prous ◽  
Allan Calux ◽  
Markus Gastauer ◽  
Gilberto Nicacio ◽  
...  

The degradation of subterranean habitats is believed to represent a serious threat for the conservation of obligate subterranean dwellers (troglobites), many of which are short-range endemics. However, while the factors influencing cave biodiversity remain largely unknown, the influence of the surrounding landscape and patterns of subterranean connectivity of terrestrial troglobitic communities have never been systematically assessed. Using spatial statistics to analyze the most comprehensive speleological database yet available for tropical caves, we first assess the influence of iron cave characteristics and the surrounding landscape on troglobitic communities from the Eastern Amazon. We then determine the spatial pattern of troglobitic community composition, species richness, phylogenetic diversity, and the occurrence of frequent troglobitic species, and finally quantify how different landscape features influence the connectivity between caves. Our results reveal the key importance of habitat amount, guano, water, lithology, geomorphology, and elevation in shaping iron cave troglobitic communities. While mining within 250 m from the caves influenced species composition, increasing agricultural land cover within 50 m from the caves reduced species richness and phylogenetic diversity. Troglobitic species composition, species richness, phylogenetic diversity, and the occurrence of frequent troglobites showed spatial autocorrelation for up to 40 km. Finally, our results suggest that the conservation of cave clusters should be prioritized, as geographic distance was the main factor determining connectivity between troglobitic communities. Overall, our work sheds important light onto one of the most overlooked terrestrial ecosystems, and highlights the need to shift conservation efforts from individual caves to subterranean habitats as a whole.


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