How Does Landscape Modification Induce Biological Homogenization in Tropical Stream Metacommunities?

Author(s)

Siqueira, Tadeu ^[1] ; Teixeira Lacerda, Camila Giaj-Levra ^[1] ; Saito, Victor S. ^[2]

Affiliation

^[1] UNESP Univ Estadual Paulista, Inst Biociencias, Dept Ecol, Rio Claro - Brazil

^[2] Univ Fed Sao Carlos, Programa Posgrad Ecol & Recursos Nat, BR-13560 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Biotropica; v. 47, n. 4, p. 509-516, JUL 2015.
• Web of Science Citations: 12

Abstract

Habitat modification can homogenize biological communities. Beta diversity analyses provide key information for understanding biotic homogenization, especially given recent conceptual and methodological advances. Here, we investigated if landscape modification was associated with taxonomic homogenization in 32 stream insect communities from the Brazilian Atlantic Forest. We investigated: (1) if the way we defined landscape affected our estimates of beta diversity; (2) to what extent changes in species composition versus relative abundance caused the observed homogenization; and (3) if environmental heterogeneity among modified habitats influenced homogenization. We detected taxonomic homogenization caused by landscape modification only when we used refined landscape categorizations and abundance-based diversity measures. For forested streams, changes in relative abundance rather than absolute taxonomic composition increased the biological variation. Forested streams were generally more heterogeneous, with a variable set of abundant genera; by contrast, non-forested streams were more homogeneous, with the same set of genera being more or less abundant. We suggest that landscape modification by agriculture, pasture, and silviculture reduces beta diversity by limiting the colonization of potential species, and, ultimately, causing taxonomic homogenization. Studies investigating biotic homogenization should include multiple dissimilarity measures representing changes in relative species abundance and community composition. Resumo A modificacAo de habitats pode causar homogeneizacAo das comunidades biologicas. A analise da diversidade beta fornece informacoes fundamentais para a compreensAo da homogeneizacAo biotica, especialmente tendo em conta os avancos conceituais e metodologicos recentes. Nos investigamos se a modificacAo da paisagem esta associada a homogeneizacAo taxonomica em 32 comunidades de insetos aquaticos da Mata Atlantica brasileira. Nos investigamos: (1) se a forma como definimos paisagens afetou nossas estimativas de beta diversidade, (2) em que medida as mudancas na composicAo de especies versus abundancia relativa causou a homogeneizacAo observada, e (3) se a heterogeneidade ambiental entre os habitats alterados afetou a homogeneizacAo. Detectamos homogeneizacAo taxonomica causada por modificacoes na paisagem somente quando usamos uma categorizacAo refinada de paisagens e medidas de diversidade beta baseadas em abundancia. Entre os riachos florestados, mudancas na abundancia relativa, e nAo na composicAo taxonomica absoluta, aumentaram a variacAo biologica. Riachos florestados foram, de modo geral, mais heterogeneos biologicamente, com um conjunto variavel de generos dominantes; por outro lado, riachos nAo florestados foram mais homogeneos, com o mesmo conjunto de generos sendo mais ou menos abundantes. Nos sugerimos que a modificacAo da paisagem pela agricultura, pastagem e silvicultura reduz diversidade beta, limitando a colonizacAo de especies potenciais, consequentemente, causando homogeneizacAo taxonomica. Estudos investigando homogeneizacAo biotica devem incluir diferentes medidas de dissimilaridade que representam mudancas na abundancia relativa das especies e na composicAo taxonomica da comunidade. (AU)

• FAPESP's process: 13/20540-0 - Process in metacommunities: ecological, evolutive and spatial factors structuring aquatic macroinvertebrates communities
• Grantee: Victor Satoru Saito
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/50424-1 - Scaling biodiversity in tropical and boreal streams: implications for diversity mapping and environmental assessment (ScaleBio)
• Grantee: Tadeu de Siqueira Barros
• Support Opportunities: Regular Research Grants