Threshold responses of Amazonian stream fishes to timing and extent of deforestation

Autor(es)

Brejao, Gabriel L. ^[1] ; Hoeinghaus, David J. ^{[2, 3]} ; Perez-Mayorga, Maria Angelica ^[1] ; Ferraz, Silvio F. B. ^[4] ; Casatti, Lilian ^[1]

Afiliação do(s) autor(es)

^[1] UNESP Sao Paulo State Univ, Dept Zool & Bot, 2265 Cristovao Colombo St, BR-15054000 Sao Jose Do Rio Preto, SP - Brazil

^[2] Univ North Texas, Dept Biol Sci, 1155 Union Circle 310559, Denton, TX 76203 - USA

^[3] Univ North Texas, Adv Environm Res Inst, 1155 Union Circle 310559, Denton, TX 76203 - USA

^[4] Univ Sao Paulo, Dept Forest Sci, Luiz de Queiroz Coll Agr, Av Padua Dias 11, Piracicaba, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Conservation Biology; v. 32, n. 4, p. 860-871, AUG 2018.
• Citações Web of Science: 7

Resumo

Deforestation is a primary driver of biodiversity change through habitat loss and fragmentation. Stream biodiversity may not respond to deforestation in a simple linear relationship. Rather, threshold responses to extent and timing of deforestation may occur. Identification of critical deforestation thresholds is needed for effective conservation and management. We tested for threshold responses of fish species and functional groups to degree of watershed and riparian zone deforestation and time since impact in 75 streams in the western Brazilian Amazon. We used remote sensing to assess deforestation from 1984 to 2011. Fish assemblages were sampled with seines and dip nets in a standardized manner. Fish species (n = 84) were classified into 20 functional groups based on ecomorphological traits associated with habitat use, feeding, and locomotion. Threshold responses were quantified using threshold indicator taxa analysis. Negative threshold responses to deforestation were common and consistently occurred at very low levels of deforestation (<20%) and soon after impact (<10 years). Sensitive species were functionally unique and associated with complex habitats and structures of allochthonous origin found in forested watersheds. Positive threshold responses of species were less common and generally occurred at >70% deforestation and >10 years after impact. Findings were similar at the community level for both taxonomic and functional analyses. Because most negative threshold responses occurred at low levels of deforestation and soon after impact, even minimal change is expected to negatively affect biodiversity. Delayed positive threshold responses to extreme deforestation by a few species do not offset the loss of sensitive taxa and likely contribute to biotic homogenization. (AU)

• Processo FAPESP: 10/17494-8 - Peixes de riachos de terra firme da Bacia do Rio Machado, RO
• Beneficiário: Lilian Casatti
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 12/21916-0 - Relações entre o processo de desmatamento e os padrões de diversidade de peixes em riachos da Amazônia Ocidental
• Beneficiário: Gabriel Lourenço Brejão
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 15/05827-6 - Relações entre o processo de desmatamento e os padrões de diversidade de peixes em riachos da Amazônia Ocidental
• Beneficiário: Gabriel Lourenço Brejão
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado
• Processo FAPESP: 09/12318-0 - O papel da vegetação secundária na conservação da biodiversidade e água na região central de Rondônia
• Beneficiário: Silvio Frosini de Barros Ferraz
• Modalidade de apoio: Auxílio à Pesquisa - Regular