scholarly journals Habitat Specificity Modulates the Response of Small Mammals to Habitat Fragmentation, Loss, and Quality in a Neotropical Savanna

2021 ◽  
Vol 9 ◽  
Author(s):  
Ingrid de Mattos ◽  
Bárbara Zimbres ◽  
Jader Marinho-Filho
Keyword(s):  
Species Composition ◽  
Functional Diversity ◽  
Habitat Loss ◽  
Habitat Quality ◽  
Small Mammals ◽  
Small Mammal ◽  
Patch Size ◽  
Landscape Configuration ◽  
Habitat Amount ◽  
Habitat Generalists

Landscape conversion of natural environments into agriculture and pasture are driving a marked biodiversity decline in the tropics. Consequences of fragmentation might depend upon habitat amount in the landscape, while the quality of remnants can also affect some species. These factors have been poorly studied in relation to different spatial scales. Furthermore, the impacts of these human-driven alterations may go beyond species loss, possibly causing a loss of ecosystem function and services. In this study, we investigated how changes in landscape configuration (patch size and isolation), habitat loss (considering a landscape gradient of 10, 25, and 40% of remnant forest cover), and habitat quality (forest structure) affect small mammal abundance, richness, taxonomic/functional diversity, and species composition in fragmented landscapes of semideciduous forests in the Brazilian Cerrado. Analyses were performed separately for habitat generalists and forest specialists. We live-trapped small mammals and measured habitat quality descriptors four times in 36 forest patches over the years 2018 and 2019, encompassing both rainy and dry seasons, with a total capture effort of 45,120 trap-nights. Regression analyses indicated that the effect of landscape configuration was not dependent on the proportion of habitat amount in the landscape to determine small mammal assemblages. However, both patch size and habitat loss impacted different aspects of the assemblages in distinct ways. Smaller patches were mainly linked to an overall increase in small mammal abundance, while the abundance of habitat generalists was also negatively affected by habitat amount. Generalist species richness was determined by the proportion of habitat amount in the landscape. Specialist richness was influenced by patch forest quality only, suggesting that species with more demanding habitat requirements might respond to fragmentation and habitat loss at finer scales. Taxonomic or functional diversity were not influenced by landscape structure or habitat quality. However, patch size and habitat amount in the landscape were the major drivers of change in small mammal species composition in semideciduous forests in the Brazilian savanna.

scholarly journals Multi-taxa ecological responses to habitat loss and fragmentation in western Amazonia as revealed by RAPELD biodiversity surveys

2021 ◽  
Vol 51 (3) ◽  
pp. 234-243
Author(s):  
Gabriel M. MOULATLET ◽  
Emmanuel AMBRIZ ◽  
Jennifer GUEVARA ◽  
Karima G. LÓPEZ ◽  
Marina RODES-BLANCO ◽  
...  
Keyword(s):  
Species Composition ◽  
Habitat Loss ◽  
Forest Cover ◽  
Landscape Fragmentation ◽  
Dung Beetles ◽  
Landscape Configuration ◽  
Edge Density ◽  
Logistic Regression Models ◽  
Habitat Loss And Fragmentation ◽  
Taxonomic Groups

ABSTRACT Habitat loss and fragmentation caused by deforestation are important anthropogenic drivers of changes in biodiversity in the Amazon rainforest, and has reached its highest rate in recent decades. However, the magnitude and direction of the effects on species composition and distribution have yet to be fully understood. We evaluated the responses of four taxonomic groups − birds, amphibians, orchid bees, and dung beetles - to habitat loss and fragmentation at both species and assemblage level in the northern Ecuadorian Amazon. We sampled fifteen 250-m long plots in terra-firme forest remnants. We calculated one landscape fragmentation index (fragindex), which considers the proportion of continuous forest cover, edge density and isolation in the landscape, and nine landscape configuration metrics. Logistic regression models and multivariate regression trees were used to analyze species and assemblage responses. Our results revealed that over 80% of birds, amphibians or orchid-bee species, and 60% of dung beetles were negatively affected by habitat loss and fragmentation. Species composition of all taxonomic groups was significantly affected by differences in forest cover and connectivity. Less than 5% of all species were restricted to landscapes with fragindex values higher than 40%. Landscape metrics related to the shape and area of forest patches determined the magnitude and direction of the effect on species responses. Therefore, changes in the landscape configuration of Ecuadorian Amazonia should be minimized to diminish the effects of habitat loss and fragmentation on species occurrence and assemblage composition.

scholarly journals Habitat quality versus spatial variables as determinants of small mammal assemblages in Atlantic Forest fragments

2015 ◽  
Vol 97 (1) ◽  
pp. 253-265 ◽  
Author(s):  
Ana C. Delciellos ◽  
Marcus V. Vieira ◽  
Carlos E. V. Grelle ◽  
Priscilla Cobra ◽  
Rui Cerqueira
Keyword(s):  
Species Richness ◽  
Atlantic Forest ◽  
Habitat Quality ◽  
Small Mammals ◽  
Small Mammal ◽  
Habitat Structure ◽  
Fragment Size ◽  
Vegetation Density ◽  
Matrix Properties ◽  
Mammal Assemblages

Abstract Fragment size, isolation, and matrix properties have received considerable attention as predictors of species richness, abundance, and composition in habitat patches. However, measurements of habitat attributes or habitat quality are more directly related to the proximate effects of habitat fragmentation and may be more determinant of assemblages than traditional explanatory variables at local scales. We determine how habitat structure in fragments—a measure of habitat quality—compares to fragment size, isolation, and matrix properties as determinants of richness, abundance, and composition of non-volant small mammals in a fragmented landscape of Atlantic Forest. Small mammals were surveyed once in 25 fragments in the Macacu River watershed, Rio de Janeiro, Brazil, from 1999 to 2001 and 2005 to 2009. A total of 83 candidate models were formulated and compared by Akaike Information Criteria. Habitat structure was one of the main determinants of small mammal assemblages in fragments, as important as fragment isolation for species composition and climatic season for species richness. Rodents were more abundant in fragments with increased overstory and understory vegetation density and more fallen logs. The contrary pattern was found for overall species richness and for species of terrestrial habit, which were more abundant in fragments with more open forest: decreased overstory and understory vegetation density and less fallen logs. Habitat quality in fragments may be a more important determinant of assemblages of small mammals and other vertebrates than previously considered in landscape and land use studies. O tamanho e isolamento dos fragmentos e as propriedades da matriz têm recebido considerável atenção como preditores da riqueza, abundância e composição de espécies em manchas de habitat. Entretanto, medidas dos atributos do habitat ou da qualidade do habitat são mais diretamente relacionadas aos efeitos imediatos da fragmentação de habitat, e seriam mais determinantes das comunidades do que as variáveis explicativas tradicionais. Determinamos como a estrutura do habitat nos fragmentos—uma medida da qualidade do habitat—se compara ao tamanho e isolamento dos fragmentos, e às propriedades da matriz como determinantes da riqueza, abundância e composição de espécies de pequenos mamíferos não-voadores em uma paisagem fragmentada de Mata Atlântica. Os pequenos mamíferos foram amostrados uma vez em 25 fragmentos na Bacia do Rio Macacu, Rio de Janeiro, Brasil, de 1999 a 2001 e de 2005 a 2009. Um total de 83 modelos foram formulados e comparados utilizando o Critério de Informação de Akaike. A estrutura do habitat foi um dos principais determinantes das comunidades de pequenos mamíferos nos fragmentos de mata, tão importante quanto o isolamento entre fragmentos para a composição de espécies e os efeitos das estações climáticas sobre a riqueza de espécies. Os roedores foram mais abundantes nos fragmentos com estratificação vertical e sub-bosque mais densos e com maior presença de troncos caídos. O padrão contrário foi encontrado para a riqueza total de espécies e para espécies de hábito terrestre, que foram mais abundantes em fragmentos com estratificação vertical e sub-bosque menos densos e menor presença de troncos caídos. A qualidade do habitat em fragmentos pode ser determinante das comunidades de pequenos mamíferos e outros vertebrados, mais importante do que considerado previamente em estudos de paisagens e uso da terra.

scholarly journals Multi-scale determinants of small mammal and lizard dimensions of diversity across Amazonian insular forest fragments

2021 ◽  
Author(s):  
Ana Filipa Palmeirim ◽  
Fabio Farneda ◽  
Marcus Vinicius Vieira ◽  
Carlos A. Peres
Keyword(s):  
Habitat Loss ◽  
Small Mammals ◽  
Small Mammal ◽  
Habitat Type ◽  
Forest Area ◽  
Small Island ◽  
Forest Fragments ◽  
Species Identity ◽  
Hydropower Development ◽  
Β Diversity

Abstract Context Hydropower development is one of the primary drivers of habitat loss and insular fragmentation. Yet, studies quantifying such effects on biodiversity are mostly limited to taxonomic metrics, often overlooking species identity and their functional and phylogenetic roles. Objectives We examined taxonomic, functional and phylogenetic responses to habitat loss and insular fragmentation of small mammals and lizards within (α) and between sites (β). Methods Both taxa were surveyed across 25 islands within the Balbina Hydroelectric Reservoir, and adjacent continuous forest, in Central Amazonia. Each dimension of diversity was related to spatial and habitat variables. We also examined functional composition using community-weighted mean trait values, and community redundancy using functional uniqueness. β-diversity was partitioned into their richness (βrich) and replacement (βrepl) components. Results Functional and phylogenetic α−diversities of both taxa mirrored the taxonomic dimension, all of which increased with forest area. Individual small mammal (body mass and matrix tolerance), and lizard traits (heliothermic mode and habitat type) were also predicted by forest area. For both taxa, species functional uniqueness decreased with forest area, and all dimensions of β-diversity were predominantly partitioned in βrich. Conclusions The environmental filter created by forest area resulted in the low conservation value associated with small forest islands, only occupied by a small set of species comprised by generalist lizards and matrix-tolerant small mammals. On the other side, large forest sites ensured ecosystem resilience to disturbance. To maintain ecosystem integrity, creating a myriad small island over large expanses of floodwaters should be avoided in future hydropower development.

scholarly journals Low impact of forest conversion on biodiversity: evidence from small mammals in contrasting forests of Mt. Liangshan, China

2021 ◽  
Author(s):  
He Xingcheng ◽  
Zhixin Wen ◽  
Zhang Dejun ◽  
Yin Xudong ◽  
Chen xue ◽  
...  
Keyword(s):  
Functional Diversity ◽  
Small Mammals ◽  
Small Mammal ◽  
Forest Conversion ◽  
Forest Types ◽  
Community Structures ◽  
Plantation Forests ◽  
The Impact ◽  
Primary Forests ◽  
Diversity Metrics

Secondary and plantation forests are the main alternative forests remaining after the deforestation of primary forests. Understanding the conservation value of secondary and plantation forests is important for resource utilization. To explore the impact of forest conversion on biodiversity, we compared multiple diversity metrics (taxonomic, phylogenetic and functional diversity) and community structures of small mammals in the primary, secondary and plantation forests on Mt. Liangshan, Sichuan Province, China. Seven field surveys were conducted to survey local small mammal assemblages between 2016 and 2020. We found that the taxonomic, phylogenetic and functional diversity metrics of small mammals in the three forest types were similar at the landscape scale, while all diversity metrics were lowest in the plantation forest and highest in the primary forests at the site scale. The community structure analysis showed that random processes were dominant across the three forest types, and there was no difference in small mammal community structures among the three forest types. Our results indicated that secondary and plantation forests in the nature reserves, adjacent to the primary forest and exposed to little human disturbance, also can provide important habitats for small mammals.

scholarly journals Effects of Long-Term Habitat Protection on Montane Small Mammals: Are Sorex araneus and S. minutus More Sensitive Than Previously Considered?

Diversity ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 38
Author(s):  
Ana Maria Benedek ◽  
Anamaria Lazăr ◽  
Niculina Viorica Cic ◽  
Maria Denisa Cocîrlea ◽  
Ioan Sîrbu
Keyword(s):  
Species Composition ◽  
Small Mammals ◽  
Biological Diversity ◽  
Sorex Araneus ◽  
Short Term ◽  
Animal Populations ◽  
Small Mammal Communities ◽  
Mammal Communities ◽  
Habitat Generalists

Protection of natural areas by restricting human activities aims to preserve plant and animal populations and whole communities, ensuring the conservation of biological diversity and enhancement of ecosystem services. Therefore, it is expected that the longer the protection, the stronger the desired effects. We evaluated the responses of small mammals at the population and community levels under protection in the southern Carpathian Mountains. We surveyed small mammals for five years in sites with long- and short-term protection and non-protected. Besides protection status, we included elevation, habitat heterogeneity, and the month of survey as predictors in our models. As response variables, we considered abundance, presence, species composition and species richness. Community abundance responded to all four predictors and species composition was influenced by protection status and month of study. The shrews Sorex araneus and S. minutus had positive responses to protection, both in terms of abundance and relative abundance (their ratio within the community). Our results suggest that overall, montane small mammal communities respond positively to long-term protection, especially S. araneus and S. minutus. These shrew species are considered habitat generalists, but they appear to be in fact sensitive to the habitat quality enhanced through protection.

scholarly journals The influence of fire on populations of small mammals of the Kruger National Park

Koedoe ◽  
1981 ◽  
Vol 24 (1) ◽  
Author(s):  
N. G Kern
Keyword(s):  
Species Diversity ◽  
Species Composition ◽  
Small Mammals ◽  
Small Mammal ◽  
National Park ◽  
Kruger National Park ◽  
Control Treatment ◽  
Mammal Species ◽  
Low Diversity ◽  
Small Mammal Species

A total of 16 000 trap-nights was employed over eleven months to examine the influence of burning on small mammal populations in two major veld-types of the Kruger National Park. Four burning treatments (control, annual August burning, triennial August and April burning) were examined in detail and the following parameters determined: small mammal species composition, population density, biomass and species diversity. The control treatment had a high, stable small mammal density, biomass and diversity; the annual burning treatment had a low diversity and was dominated by Tatera leucogaster. The triennial burning treatments showed a cycle of species composition from domination by T. leucogaster following burning, through domination by other rodent species to domination by Crocidura hirta at the end of the cycle. The distributions and movements of the small mammals can be explained in terms of cover and litter preferences.

Understory use by terrestrial small mammals in an unflooded forest patch in the Pantanal floodplain

Mammalia ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Nayara Yoshie Sano ◽  
Heitor Miraglia Herrera ◽  
Grasiela Edith de Oliveira Porfirio ◽  
Filipe Martins Santos
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Understory Vegetation ◽  
Monodelphis Domestica ◽  
Forest Patch ◽  
Habitat Features ◽  
Species Characteristics ◽  
Local Habitat

AbstractTo date, there have been no studies that have evaluated small mammal utilization of the understory of forests. In this study, we described the use of vertical strata by small mammals in patches of unflooded forests, known as “cordilheiras”, in the Nhecolândia sub-region of the Pantanal, Brazil. We collected all species using the ground and understory, including the terrestrial didelphid Monodelphis domestica. We suppose that local habitat features (e.g., Acuri palms), rather than intrinsic species characteristics, may be more conducive to the use of understory vegetation by small mammals in the Nhecolândia region.

scholarly journals Repeated surveying over 6 years reveals that fine-scale habitat variables are key to tropical mountain ant assemblage composition and functional diversity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mulalo M. Muluvhahothe ◽  
Grant S. Joseph ◽  
Colleen L. Seymour ◽  
Thinandavha C. Munyai ◽  
Stefan H. Foord
Keyword(s):  
Climate Change ◽  
Species Composition ◽  
High Altitude ◽  
Functional Diversity ◽  
Large Scale ◽  
Climate Models ◽  
Spatial Scales ◽  
Abiotic Factors ◽  
Composition Analysis ◽  
Fine Scale

AbstractHigh-altitude-adapted ectotherms can escape competition from dominant species by tolerating low temperatures at cooler elevations, but climate change is eroding such advantages. Studies evaluating broad-scale impacts of global change for high-altitude organisms often overlook the mitigating role of biotic factors. Yet, at fine spatial-scales, vegetation-associated microclimates provide refuges from climatic extremes. Using one of the largest standardised data sets collected to date, we tested how ant species composition and functional diversity (i.e., the range and value of species traits found within assemblages) respond to large-scale abiotic factors (altitude, aspect), and fine-scale factors (vegetation, soil structure) along an elevational gradient in tropical Africa. Altitude emerged as the principal factor explaining species composition. Analysis of nestedness and turnover components of beta diversity indicated that ant assemblages are specific to each elevation, so species are not filtered out but replaced with new species as elevation increases. Similarity of assemblages over time (assessed using beta decay) did not change significantly at low and mid elevations but declined at the highest elevations. Assemblages also differed between northern and southern mountain aspects, although at highest elevations, composition was restricted to a set of species found on both aspects. Functional diversity was not explained by large scale variables like elevation, but by factors associated with elevation that operate at fine scales (i.e., temperature and habitat structure). Our findings highlight the significance of fine-scale variables in predicting organisms’ responses to changing temperature, offering management possibilities that might dilute climate change impacts, and caution when predicting assemblage responses using climate models, alone.

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