Distribution and abundance of freshwater decapods in an Atlantic rainforest catchment with a dammed future

Abstract

Variations in physical characteristics along the course of a river influence habitat availability which reflects in species distribution. Knowledge of ecology and diversity of lotic species is important for evaluating how river ecosystems will respond to environmental impacts. Freshwater decapods are a group of high ecological and economic importance, but the knowledge about factors influencing their distribution is scarce in Brazil. We performed a survey of decapods to describe their abundance and distribution as well as to study their relationships with stream physical variables and especially their association with different substrates types. We studied 23 sites located in 15 tributaries of Guapiaçú River, RJ, where we collected decapods in different substrates types and measured a set of physical variables. We found five decapods species, including amphidromous and non-amphidromous shrimps and crabs. Decapods were strongly associated with leaf-litter substrates and their abundance was related to a multivariate axis describing longitudinal changes in stream characteristics. We concluded that decapods occurring in the Guapiaçú catchment inhabit mainly small streams with preserved riparian forests where they find shelter and potential prey of invertebrates. The ongoing project to build a dam on the Guapiaçú River will have negative consequences to migrating shrimps and we strongly recommend that mitigating actions, such the construction of structures to allow the passage of migrating fauna, should be taken.Keywords: shrimps, environmental factors, leaf litter, tropical stream, damming. Distribuição e abundância de decápodes de água doce e sua associação com variáveis ambientais em uma bacia hidrográfica de Mata Atlântica que será represada ResumoVariações nas características físicas de um rio ao longo do seu curso influenciam a disponibilidade de habitas e dessa forma a distribuição de espécies. O conhecimento sobre a ecologia e diversidade de espécies lóticas é importante para avaliar como esses ecossistemas responderão a impactos ambientais. Decápodes de água doce são um grupo de grande importância ecológica e econômica, contudo o conhecimento sobre fatores influenciando sua distribuição ainda é escasso no Brasil. Nós realizamos um levantamento de decápodes para descrever sua abundância e distribuição, bem como estudar sua relação com características físicas dos rios, especialmente sua associação com tipos diferentes de substrato. Nós estudamos 23 localidades distribuídas em 15 rios tributários do Rio Guapiaçú, RJ, onde coletamos decápodas em diferentes tipos de substratos e medimos um conjunto de variáveis físicas. Nós encontramos cinco espécies de decápodas incluindo camarões anfídromos e não anfídromos e caranguejos. Esses organismos foram fortemente associados a substratos de folhiço alóctone e sua abundância foi relacionada com um eixo PCA que descreve as mudanças nas características físicas longo do curso do rio. Nós concluímos que os decápodas que ocorrem na bacia do Rio Guapiaçú habitam princi...

Forest conversion adversely affects native Macrobrachium shrimp assemblages in tropical Malaysian streams

“…Although fish communities have been found to be strongly associated with woody material (Wright & Flecker, 2004; Chua et al, 2020), this relationship is not significant for Macrobrachium species. This suggests a greater reliance of Macrobrachium on leaf litter microhabitats for foraging and refuge (Crowl et al, 2001; March et al, 2001; Silva‐Junior, Silva‐Araújo & Moulton, 2017) and highlights the importance of a diverse array of microhabitats for aquatic biodiversity in general.…”

Species richness and longitudinal distribution of crustaceans in the Logawa River, Banyumas, Indonesia

“…Hazeri et al (2019) reported that crustacean species depend on the availability of habitat structure. In detail, Silva-Junior et al (2017) reported that decapods were more abundant in leaf litter substrates than in sandy areas. In the Logawa River, leaf litter substrate was predicted to have originated from the tributary before Station II and the stream before Stations IV, V, and VI ( Figure 1).…”