Spatiotemporal changes in feeding ecology of brook trout in sub-alpine lakes at Gaspésie National Park

Abstract

As a result of strong anthropogenic impacts such as climate change, invasive species and extreme weather, freshwater ecosystems are facing global degradation. Due to these effects the understanding of a changing environment is being more and more frequently studied in order to cope with such changes. A central part of understanding species reaction toward environmental changes is by studying the feeding ecology which provides many aspects of trophic interactions. The main objective in this research is to assess spatial and temporal changes in the feeding ecology of brook trout (Salvelinus fontinalis) inhabiting alpine lakes via stomach content analysis. Because feeding strategy for opportunistic feeders like brook trout was long believed to not practice individual specialization, this study aims to dig deeper into the examination of individual specialization within generalist populations. The feeding ecology of brook trout was investigated with various indices related to diet overlap, individual specialization, and species diversity. This research also estimates the relative importance for all prey items as well as group them in the following prey groups: fish, zooplankton, terrestrial invertebrates, and benthic macroinvertebrates. The general pattern, show that the different populations did not exhibit either strong specialization or strong generalization in feeding strategy among brook trout populations. However, some populations expressed seasonal variation indicating that they indeed were individual specialists among the generalist population and vise versa. This research suggested that the most explanatory reason for some prey items being highly represented in their diet was because of prey availability and abundance. This research has contributed to a broader understanding of freshwater ecosystem dynamics in alpine lakes. Additionally, the results from this research can be used to inform conservation efforts, aiming to preserve biodiversity and ecosystem resilience in the face of global environmental changes.

As a result of strong anthropogenic impacts such as climate change, invasive species and extreme weather, freshwater ecosystems are facing global degradation. Due to these effects the understanding of a changing environment is being more and more frequently studied in order to cope with such changes. A central part of understanding species reaction toward environmental changes is by studying the feeding ecology which provides many aspects of trophic interactions. The main objective in this research is to assess spatial and temporal changes in the feeding ecology of brook trout (Salvelinus fontinalis) inhabiting alpine lakes via stomach content analysis. Because feeding strategy for opportunistic feeders like brook trout was long believed to not practice individual specialization, this study aims to dig deeper into the examination of individual specialization within generalist populations. The feeding ecology of brook trout was investigated with various indices related to diet overlap, individual specialization, and species diversity. This research also estimates the relative importance for all prey items as well as group them in the following prey groups: fish, zooplankton, terrestrial invertebrates, and benthic macroinvertebrates. The general pattern, show that the different populations did not exhibit either strong specialization or strong generalization in feeding strategy among brook trout populations. However, some populations expressed seasonal variation indicating that they indeed were individual specialists among the generalist population and vise versa. This research suggested that the most explanatory reason for some prey items being highly represented in their diet was because of prey availability and abundance. This research has contributed to a broader understanding of freshwater ecosystem dynamics in alpine lakes. Additionally, the results from this research can be used to inform conservation efforts, aiming to preserve biodiversity and ecosystem resilience in the face of global environmental changes.