Dados do Trabalho

TÍTULO

SPATIAL HETEROGENEITY AND HABITAT CONFIGURATION OVERCOME HABITAT COMPOSITION INFLUENCES ON ALPHA AND BETA MAMMAL DIVERSITY

Resumo

Habitat fragmentation involves changes in landscape composition, configuration, and habitat quality, affecting both natural vegetation patches and the anthropogenic matrix. The effects of landscape modifications on biodiversity are currently subject to intense debate, and disentangling them is of utmost importance to support conservation strategies. We evaluated the importance of landscape composition, configuration, and spatial heterogeneity to explain α- and β-diversity of mammals within heterogeneous and fragmented landscapes. We expected species richness to be positively related to all predictive variables, with the strongest relationship with landscape composition, followed by configuration and spatial heterogeneity, respectively. We also expected landscape to influence both β-diversity components (nestedness and turnover), in the same order of importance expected for species richness, and with a stronger influence on the nestedness component due to deterministic loss of species more sensitive to habitat disturbance. We recorded small to large-sized mammal occurrences over 20 landscapes within Brazil and analyzed landscape structure using: i) thematic mapping of habitat features and ii) measures of spatial heterogeneity based on vegetation indexes derived from satellite images. We compared a set of models to explain species richness using the Akaike Information Criterion and evaluated the effects of differences in predictive variables between pairs of landscapes on both β-diversity components using a Multiple Regression on distance Matrix. We found that, against our expectations, landscape configuration was the main driver of species richness, followed by spatial heterogeneity and last by landscape composition. Species nestedness was explained, in order of importance, by spatial heterogeneity, landscape configuration, and landscape composition. Although conservation policies tend to focus mainly on habitat amount, we advocate that landscape management must include strategies to preserve and improve habitat quality and complexity in natural patches and the surrounding matrix, enabling landscapes to harbor higher species diversity.

Palavras-chave

image texture, biotic homogenization, fragmentation, habitat modelling, species losses

Financiamento

Funding - ALR receives a doctoral scholarship  (CNPq #153423/2016-1), LSMS receives a doctoral fellowship from the São Paulo Research Foundation - FAPESP (#2015/25316–6 and #2017/15772–0), FM has a post-doctoral scholarship (CAPES/PNPD #20131509), MCR was funded by FAPESP (#2013/50421-2), (CAPES/PROCAD #88881.068425/2014-01) and receives a research grant from CNPq (#312045/2013-1; #312292/2016-3), and NCC is a research fellow at CNPQ (Ecology). TSFS received a research grant from CNPq (##310144/2015-9) during part of the study.