Predicting how climate change and globally invasive piscivorous fishes will interact to threaten populations of endemic fishes in a freshwater biodiversity hotspot

Abstract

Freshwater ecosystems are highly vulnerable to the detrimental impacts of both biological invasions and climate change. Piscivorous alien fishes drive populations of small-bodied native fishes to extinction and warming is already driving extreme temperature events in lakes and rivers globally. Here, we use Ecological Niche Modelling (ENM) to predict how climate change will alter the geographical space of six alien fishes and five native fish genera (which include multiple endemic species) in Turkey, a hotspot of freshwater fish diversity. The models predicted that the geographical space of the alien fishes already present in Turkey would generally increase (including pikeperch Sander lucioperca and perch Perca fluviatilis), but with the most substantial increases in largemouth bass Micropterus salmoides, a species not yet present in Turkey but that is invasive in countries nearby and is highly popular for sport angling.For the native fish genera, general predictions were for reduced geographical space, especially in the south and east of the country, suggesting the endemic species will become increasingly imperilled in future. Their populations will also be at increasing risk of deleterious impacts from the alien piscivores, as the predictions were also for increasing overlaps in the geographical space of both the alien fishes and native fish genera. These predictions suggest that the conservation of these endemic species need to consider measures on preventing both the introduction of alien species (e.g. largemouth bass) and the further dispersal of extant alien species (e.g. pikeperch), as well as habitat interventions that will limit the effects of climate change on their populations. These results also indicate that the combination of climate change and alien invasions could have substantial impacts on this -and similar -hotspots of freshwater diversity.

Biological invasions are a population‐level rather than a species‐level phenomenon

“…These selections produce offspring with mean trait values shifted relative to those of their original parent's population, facilitating local adaptation and possibly resulting in a greater likelihood of invasion and consequent spread and impact (Briski et al., 2018). It has been widely evidenced that species undergoing the transport phase do not automatically establish in the new area; their survival hinges upon the prevailing environmental conditions and biotic filters occurring at the local scale (Aksu et al., 2021; Emiroğlu et al., 2023).…”

Shedding light on conservation strategies for the invasive species Potamopyrgus antipodarum under changing climate

“…In freshwater ecosystems, two of the most prevalent drivers of global environmental change are climate change and invasive species (Emiroğlu et al 2023). By raising the temperature of the water, changing stream ow patterns, and increasing precipitation regimes, climate change will severely affect freshwater systems.…”

“…Consequently, these introductions have often resulted in species becoming invasive in their new habitats (Dukes and Mooney 2004). Moreover, climate change serves as another major driver of non-native species introductions and their ecological impact (Emiroğlu et al 2023) as temperature increases and precipitation regime changes will lead to the formation of new suitable habitats (Rahel and Olden 2008). Together, these factors contribute to the heightened risk of invasive species establishment and proliferation worldwide.…”

Interactions of invasive pumpkinseed with a riverine endemic fish indicate trophic overlap but minimal consequences for somatic growth and condition

“…Though not so wide-spread, pumpkinseed has established populations in Turkey (Tarkan et al, 2015) but still there is no report on their invasive populations causing ecological impacts, which could also be due to lack of relevant studies. Future climate change models predicted a country-scale range expansion of pumpkinseed and potential niche overlaps with some common endemic cyprinid species (Emiro glu et al, 2023), with likely increases in dispersal via fluvial networks. Thus, the negligible ecological impact found in the present study should be approached with caution, as pumpkinseed is likely to spread to other systems under future scenarios of climate change where detrimental impacts could be incurred.…”