When roads cross streams: fish assemblage responses to fluvial fragmentation in lowland Amazonian streams

Autor(es)

Gabriel L. Brejão ^[1] ; Fabrício B. Teresa ^[2] ; Pedro Gerhard ^[3]

Afiliação do(s) autor(es)

^[1] Universidade Estadual Paulista “Júlio de Mesquita Filho”. Departamento de Zoologia e Botânica - Brasil

^[2] Universidade Estadual de Goiás. Campus de Ciências Exatas e Tecnológicas - Brasil

^[3] Embrapa - Brasil

• Tipo de documento: Artigo Científico
• Fonte: Neotropical Ichthyology; v. 18, n. 3 2020-09-04.

Resumo

ABSTRACT Roads affect biodiversity by increasing mortality rates, habitat loss, and natural landscape fragmentation. Poorly installed culverts can impound streams, changing the environmental conditions, and affecting aquatic communities. We evaluated the effects of road crossings on the taxonomic composition and functional structure of fish assemblages in lowland eastern Amazonian streams, Brazil. We tested the hypothesis that the presence of road-derived impoundments affects assemblage taxonomic and functional composition and structure. Two predictions were addressed: (1) Species and functional group composition will differ in impounded reaches in relation to lotic reaches; (2) Assemblages in downstream lotic reaches will be richer in species and functional groups in relation to upstream lotic and impoundment reaches. We sampled five streams crossed by roads presenting impoundment formation, conducted by visual census (day, dusk, and night) in 200 m line transects. Assemblage composition from lentic reaches was different from lotic reaches, and Shannon diversity from downstream reaches was different from upstream and impoundment, however, beta diversity partitioning between lotic reaches showed higher nestedness contribution, reinforcing the role of impoundment in limiting fish dispersal between lotic reaches. These results suggest that impoundments impose environmental and dispersal constraints to fish, affecting their longitudinal distribution in streams fragmented by roads. (AU)

• Processo FAPESP: 18/11954-9 - Redes fluviais como conectoras da paisagem: a qualidade das conexões ripárias influencia os padrões de diversidade de peixes de riachos?
• Beneficiário: Gabriel Lourenço Brejão
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado