Thresholds in the relationship between functional diversity and patch size for mammals in the Brazilian Atlantic Forest

Author(s)

Magioli, M. ^[1] ; Ribeiro, M. C. ^[2] ; Ferraz, K. M. P. M. B. ^[1] ; Rodrigues, M. G. ^[3]

Affiliation

^[1] Univ Sao Paulo, Escola Super Agr Luiz de Queiroz, Dept Ciencias Florestais, Lab Ecol Manejo & Conservacao Fauna Silvestre, BR-13418900 Piracicaba, SP - Brazil

^[2] Univ Estadual Paulista, Dept Ecol, Lab Ecol Espacial & Conservacao, Rio Claro, SP - Brazil

^[3] Minist Meio Ambiente, Inst Chico Mendes Conservacao Biodiversidade, Area Relevante Interesse Ecol Matao de Cosmopolis, Campinas, SP - Brazil

• Document type: Journal article
• Source: ANIMAL CONSERVATION; v. 18, n. 6, p. 499-511, DEC 2015.
• Web of Science Citations: 23

Abstract

Patch size affects abundance and diversity of mammal species, but there is little information on threshold regarding this relationship or relating it to functional diversity. Therefore, we aimed with this study to (1) evaluate if the functional diversity of medium-and large-sized mammal assemblages can be explained by patch size; (2) if this relationship is positive, evaluate whether it is linear (neutral hypothesis) or has critical thresholds (threshold hypothesis); (3) propose specific conservation strategies for each situation. We used primary and secondary mammal database for different forest remnants sizes in the Brazilian Atlantic Forest biome. We calculated functional diversity (FD), using an ecologically meaningful set of traits: body mass and locomotion form, behavioral and dietary traits, and environmental sensitivity of species. We compared linear models with threshold models using Akaike information criterion (AIC). FD values increased with patch size, possibly associated with the high complexity and heterogeneity of larger areas. The threshold model better explained the pattern between FD values and patch sizes than the linear one (delta AIC = 35.8), confirming our threshold hypothesis. Two thresholds (at 60 and 2050 ha) were identified. Our results highlight the need of compliance with the Brazilian Forest Code for assemblages in fragments lower than 60 ha. For assemblages in fragments between the two thresholds whose FD values significantly increased with patch size, we recommend improvements in conservation planning. For assemblages in fragments bigger than 2050 ha, we suggest the establishment of new protected areas, or at least, the maintenance of the existent ones. Our approach can serve as the basis for analysis with other taxonomic groups and ecosystems, increasing chances of maintaining faunal ecological functions, and improving species conservation. (AU)

• FAPESP's process: 14/09300-0 - Trophic ecology, functional diversity and occurrence of terrestrial mammals in the Atlantic Forest
• Grantee: Katia Maria Paschoaletto Micchi de Barros Ferraz
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/50421-2 - New sampling methods and statistical tools for biodiversity research: integrating animal movement ecology with population and community ecology
• Grantee: Milton Cezar Ribeiro
• Support Opportunities: Regular Research Grants