Climate change sensitivity of threatened, and largely unprotected, Amazonian fishes

Abstract

1. Climate change is poised to have fundamental impacts on the freshwater environments of the Amazon River Basin, and protected areas are routinely proposed as a possible management strategy to conserve freshwater fishes. However, there remains a paucity of information regarding the sensitivity of threatened fish species to climateinduced changes in water quantity and quality.2. An expert-based survey was used to address the following questions: (1) Are currently threatened fish species in Brazil also sensitive to projected effects of climate change? (2) Does the current conservation status of fish species also reflect their degree of sensitivity to climate change? and (3) What are the specific aspects of climate change that are likely to contribute the most to species sensitivity?3. Survey respondents evaluated 35 species (11 families) representing 50% of the threatened species in the Brazilian Amazon. The results suggest that the majority of threatened Brazilian fish species are considered highly sensitive to climate change impacts.4. Climate-induced changes in water quality were, on average, considered a greater threat to species persistence than potential changes in water quantity. Survey results also suggest that fishes exhibit high sensitivity to changes in temperature and dissolved oxygen, and moderate to high sensitivity to changes in high-flow (i.e. flood) and low-flow (i.e. drought) regimes. 5. A considerable mismatch was found between species conservation status and sensitivity to climate change, suggesting that perceptions of present-day extinction risk do not necessarily provide insight into future risks associated with climate change.6. Species sensitivity to climate change showed no relationship to dispersal ability, indicating that protected areas may serve as important refugia for those species unable to keep pace with climate change. Despite this, the number and size of protected areas in Brazil have decreased over the past decade, largely to support the exploitation of hydropower and mining. Strategic conservation planning that involves existing and new protected areas for those species most at risk to climate change is warranted.

Assessing conservation priorities of endemic freshwater fishes in the Tropical Andes region

“…This is important because susceptibility of freshwater fishes to climate change in the Tropical Andes does not appear to be related to their level of threat, as only 11% of the threatened species are also vulnerable to climate change (Carr & Tognelli, ). This mismatch between the current conservation status of a species and its vulnerability to emerging climate‐related threats has also been reported for fishes in California (Moyle, Kiernan, Crain, & Quiñones, ), the Brazilian Amazon (Frederico, Olden, & Zuanon, ), and globally (Comte & Olden, ). Species that are vulnerable to climate change but are not currently threatened could easily go under the conservation radar, as there are no current imminent threats to them, suggesting that perceptions of current extinction risk do not necessarily provide insight into future risks associated with climate change (Frederico et al, ).…”

“…This mismatch between the current conservation status of a species and its vulnerability to emerging climate‐related threats has also been reported for fishes in California (Moyle, Kiernan, Crain, & Quiñones, ), the Brazilian Amazon (Frederico, Olden, & Zuanon, ), and globally (Comte & Olden, ). Species that are vulnerable to climate change but are not currently threatened could easily go under the conservation radar, as there are no current imminent threats to them, suggesting that perceptions of current extinction risk do not necessarily provide insight into future risks associated with climate change (Frederico et al, ). In this regard, the results of this study can be crucial in advocating the protection of native fish populations in need, and for proactive climate adaptation planning, such as restoration, land purchases, and management actions tending to enhance the resilience of riverine ecosystems, and to minimize the impacts (Palmer et al, ).…”

A network meta‐analysis of threats to South American fish biodiversity

“…Climate change can be conspicuous even in remote areas that have somehow been preserved. While Amazonian river flood pulses regulates the structure of fish communities, half of the endangered species in this system can disappear due to climate change (Frederico et al., ), which is combined with other threats in the Amazon including pressure from deforestation, damming, and introduction of non‐natives (Padial et al., ). Water level fluctuation and flood pulses are also associated with changes in thermal regimes (Junk, Bayley, & Sparks, ) or human activities (Pereira, Tencatt, Dias, de Oliveira, & Agostinho, ).…”

“…Brazil is the most significant fish producer, but the last official report of catch data to FAO occurred in 2014 (FAO ). Such reports frequently lack by‐catch information, as well as realistic fishing effort and time‐series data (Frederico, Olden, & Zuanon, ). In some regions like the Brazilian semiarid, local fish biodiversity is basically related to introductions (Petrere, ), which threatens native fish communities (Bezerra, Angelini, Vitule, Coll, & Sánchez‐Botero, ) and misinform the actual conservation status (Pelicice et al., ).…”

Fishes from the Jaru Biological Reserve, Machado River drainage, Madeira River basin, Rondônia State, northern Brazil

“…Jaru Biological Reserve) (Bruner et al 2001) or conservation of fish species (Frederico et al 2016). Historically, the majority of the current protected areas in Brazil were created with disregard for the aquatic environment (Agostinho et al 2005, Abell et al 2007.…”