TY - JOUR
T1 - Longitudinal changes on ecological diversity of Neotropical fish along a 1700 km river gradient show declines induced by dams
AU - López-Rodríguez, Anahí
AU - Meerhoff, Mariana
AU - D'Anatro, Alejandro
AU - de Ávila-Simas, Sunshine
AU - Silva, Ivana
AU - Pais, Joaquín
AU - Teixeira de Mello, Franco
AU - Reynalte-Tataje, David Augusto
AU - Zaniboni-Filho, Evoy
AU - González-Bergonzoni, Iván
N1 - Publisher Copyright:
© 2024 Associação Brasileira de Ciência Ecológica e Conservação
PY - 2024/4
Y1 - 2024/4
N2 - In naturally flowing waters, communities are expected to increase their taxonomic and functional diversity as well as increase the complexity of food web architecture along the longitudinal gradient from headwaters to mouth. However, these theories do not necessarily apply to dammed rivers. We analysed fish communities at 12 locations along the 1700 km stretch of the transnational Uruguay River. We determined species richness, beta-diversity and its components (turnover and nestedness), trophic diversity, and isotopic niches at community level, with particular focus on areas upstream and downstream of the four existing dams. We estimated trophic diversity metrics based on diet analysis, and isotopic niche breadth based on Bayesian isotopic niche models. We detected consistent longitudinal changes, supporting predictions from the River Continuum Concept. However, taxonomic richness, trophic diversity, and isotopic niche decreased abruptly immediately downstream of dams, and the component contributing the most to beta diversity was turnover, with the highest values occurring mainly after the cascade of dams in the upper Uruguay River, fitting expectations from the Serial Discontinuity Concept. The dam-free stretches of the Uruguay River allowed the recovery of ecological diversity as fish richness and trophic and isotopic niche increased. The negative impacts of dams should urgently be considered in the Neotropics, where many large dams are projected.
AB - In naturally flowing waters, communities are expected to increase their taxonomic and functional diversity as well as increase the complexity of food web architecture along the longitudinal gradient from headwaters to mouth. However, these theories do not necessarily apply to dammed rivers. We analysed fish communities at 12 locations along the 1700 km stretch of the transnational Uruguay River. We determined species richness, beta-diversity and its components (turnover and nestedness), trophic diversity, and isotopic niches at community level, with particular focus on areas upstream and downstream of the four existing dams. We estimated trophic diversity metrics based on diet analysis, and isotopic niche breadth based on Bayesian isotopic niche models. We detected consistent longitudinal changes, supporting predictions from the River Continuum Concept. However, taxonomic richness, trophic diversity, and isotopic niche decreased abruptly immediately downstream of dams, and the component contributing the most to beta diversity was turnover, with the highest values occurring mainly after the cascade of dams in the upper Uruguay River, fitting expectations from the Serial Discontinuity Concept. The dam-free stretches of the Uruguay River allowed the recovery of ecological diversity as fish richness and trophic and isotopic niche increased. The negative impacts of dams should urgently be considered in the Neotropics, where many large dams are projected.
KW - Beta diversity
KW - Fish diversity
KW - Habitat fragmentation
KW - Isotopic niche
KW - Longitudinal gradient
KW - Trophic diversity
UR - http://www.scopus.com/inward/record.url?scp=85190736215&partnerID=8YFLogxK
U2 - 10.1016/j.pecon.2024.03.003
DO - 10.1016/j.pecon.2024.03.003
M3 - Journal article
AN - SCOPUS:85190736215
SN - 2530-0644
VL - 22
SP - 186
EP - 195
JO - Perspectives in Ecology and Conservation
JF - Perspectives in Ecology and Conservation
IS - 2
ER -