Impact of anthropogenic disturbances on a diverse riverine fish assemblage in Fiji predicted by functional traits

Abstract

Anthropogenic disturbances particularly affect biodiversity in sensitive freshwater ecosystems by causing species loss. Thus, measuring the response of species to multiple disturbances is a key issue for conservation and environmental management. As it is not practical to assess the response of every species in a community, we compared the performance of trait and taxonomic-based groupings of species for their abilities to predict species loss in a threatened freshwater fish assemblage. Specifically, we examined responses of a Fijian freshwater fish assemblage to deforestation, placement of anthropogenic barriers (overhanging culverts) and the presence of introduced cichlids. Species grouped by traits showed more consistent responses to disturbances than taxonomic groups. In particular, species belonging to trait groups that were estuary associated favoured medium-to-hard substrate, while feeding specialists were highly likely to be absent in catchments with high deforestation and overhanging culverts. The presence of introduced cichlids (Oreochromis mossambicus and O. niloticus) had a smaller effect than deforestation and barriers, but was negatively associated with species richness of diadromous species with climbing ability and positively associated with presences of some piscivores. The trait groups also revealed that detritivores, species favouring soft substrate, and those with a broad dietary range were less sensitive to anthropogenic disturbances. Our study indicates that using traits to predict species loss from disturbed environments can aid in detecting the responses of rare species to disturbance. In addition, we provided a method to estimate the consistency of species’ responses to disturbance. This study may ultimately help managers identify the most effective actions for conserving sensitive species that are seldom recorded in surveys

Climbing for dummies: recommendation for multi‐specific fishways for the conservation of tropical eels and gobies

“…The diadromous life cycle of eels and sicydiines makes these species particularly sensitive to the impact of instream barriers (Han et al ., 2008; Rolls, 2011). Many dams and other manmade structures impede their migrations throughout their distribution range (Holmquist, Schmidt‐Gengenbach & Yoshioka, 1998; Lagarde et al ., 2020 b ; Lin et al ., 2017). Most fishways at dams focus on upstream passage, but diadromous species have a life cycle that also requires downstream passage.…”

Los modelos de cambio climático futuro como predictores de la reducción del área de distribución de dos especies de cíclidos endémicos de Honduras

“…Sumado a esto, los cambios en las condiciones climáticas afectan las tasas metabólicas basales (Kua et al, 2020), la dinámica energética, alteran el hábitat, la conectividad, afectando la supervivencia, distribución y reproducción (Asase et al, 2021;Lenoir et al, 2019). Por lo que se pone de manifiesto la importancia de los esfuerzos de conservación en esta zona, ya que además del cambio climático, también enfrentan otras amenazas como la contaminación, el cambio de uso de la tierra, la alteración del hábitat, las enfermedades y especies invasoras, que se han identificado como factores de disminución de las poblaciones de peces de agua dulce (Arthington et al, 2016;Lin et al, 2017;Yousefi et al, 2020). Con respecto a A. hogaboomorum, los resultados sugieren que la red de áreas protegidas no proporciona una cobertura suficiente para conservar a este cíclido endémico, que está restringida únicamente a la cuenca del Pacífico.…”

Partitioning fish communities into guilds for ecological analyses: an overview of current approaches and future directions

“…For example, the investigator must decide which distance measures to use to quantify similarity of species to each other, as well as the form of linkage (tree building) methods. Previous distance measures used in guild analysis include, but are not limited to, the Bray-Curtis dissimilarity index (e.g., Liu et al 2019), Euclidean distances (e.g., Córdova-Tapia and Zambrano 2016), and Gower's dissimilarity index (e.g., Lin et al 2017). The choice of distance measure may be influenced by the types of data available (e.g., using Gower's dissimilarity index when data are continuous and categorical, including binary); however, such decisions may also be made in a rather arbitrary manner without careful consideration.…”

“…This is beneficial when working with large data sets that contain many species and when comparing across communities. Further, by focusing on function and resource use, guild analyses have the potential to create more meaningful groupings than those determined by taxonomy in questions of community ecology, as the latter are based solely on evolutionary relatedness and do not consider divergence of function in closely related species, nor the convergence of traits among evolutionarily distant species (Macnaughton et al 2016;Lin et al 2017). Another major benefit of the guild approach is its versatility.…”