Related Experiment Video
Updated: Jan 31, 2026

Modeling the Size Spectrum for Macroinvertebrates and Fishes in Stream Ecosystems
Published on: July 30, 2019
Historic deforestation reaches riparian thresholds that reduce fish diversity, particularly in unprotected streams of
Lucas Pires Oliveira1, Maria João Feio2, Ronaldo S Silva3
1University of Coimbra, Faculty of Sciences and Technology, Department of Life Sciences, Marine and Environmental Sciences Centre, Associate Laboratory ARNET, Coimbra, Portugal; Universidade Federal do Pará, Programa de Pós-Graduação em Ecologia, Rua Augusto Corrêa, 66075-110, Belém, PA, Brazil.
Abstract:
The aquatic ecosystems of the Amazon are under increasing pressure from land-use and land-cover changes, primarily driven by agricultural expansion, infrastructure development, and logging. This study investigated the relationship between riparian vegetation loss (RVL) over time (up to 38 years) and fish biodiversity in streams of southwestern Amazonia, assessing the extent to which protected areas mitigate these impacts. We sampled 35 first to third-order streams in two Extractive Reserves in Acre, Brazil: Chico Mendes (RESEX-CM), including streams within the reserve and its buffer zone, and Cazumbá-Iracema (RESEX-CI). A total of 127 fish species were recorded: 75 for RESEX-CI, 60 for RESEX-CM, and 58 for streams in UPA (unprotected areas). UPA streams had greater RVL and lower species richness (median = 10.5) than RESEX sites (median = 15-21). No significant differences were found between RESEX sites, highlighting impact mitigation. Species richness began to decline 15 years prior to sampling, with losses linked to higher riparian vegetation loss (RVL), cumulative magnitude, and longer durations of RVL. Sensitive species and functional groups both responded to small RVL losses, from 0.84 to 11.43 % and 1.86-34.98 %, respectively. The results reinforce the importance of protected areas for the conservation of water bodies and fish assemblages in southwestern Amazonia. However, they also highlight impacts that exceed legal limits for riparian vegetation. These findings provide insights for improved riparian vegetation management, considering both the extent and duration of vegetation loss.
Related Concept Videos
Stream Function
Osmoregulation in Fishes
Diversity of Archaea I
Cell Diversity
Multicellular...
Diversity of Archaea II
Diversity of Protists I

