ALIENFISH&CLIMCHANGE

Modelling of non-native fish species responses to climate change

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 Obiettivo del progetto (Objective)

'Non-native species introductions are a major concern in Europe and globally, threatening biodiversity, ecosystem function and global economies; this will be exacerbated with climate change. Current climate change models for Europe and the UK predict: progressively warmer, wetter winters; warmer, dryer summers; an increase in extreme river flows. This is likely to increase the risk of non-native species reproductive potential and dispersal, which are key factors in establishment success. Using pumpkinseed Lepomis gibbosus in ambient and warm-water conditions as a case study, the Fellowship aims to: 1) Assess pumpkinseed growth and reproductive traits in nature (using methods currently employed for the species); 2) Acquire estimates of spawning event frequency in nature and in the lab to assess reproductive output (direct observation in semi-natural ponds via a novel telemetry array system, and in lab experiments, plus egg size distribution analysis on wild caught fish); 3) Determine pumpkinseed dispersal rates from floodplain water bodies into receiving streams (using drift nets to estimate propagule pressure); and 4) Develop (or improve existing) models of pumpkinseed reproductive output and dispersal (using relationships between juvenile growth and mean age at maturity, gravity models to assess the dispersal process, and GIS software to produce risk maps to aid in identifying areas at risk of biological invasion). The proposed fellowship is particularly novel in aiming to two important and timely questions relevant to the assessment of risks posed by non-native species in general, and of pumpkinseed in particular: 1) Will climate warming increase the risk of non-native fish establishing self-sustaining populations? 2) Will increased variability in precipitation and river discharge increase the risk of non-native fishes expanding their current ranges? The MC Fellow will receive invaluable training and experience, which will enhance his career prospects at home.'

Introduzione (Teaser)

Fish scientists have studied the environmental biology and reproductive behaviour of the pumpkinseed sunfish, a non-native species from North America. The investigation has been conducted to determine the effect of global warming on the biodiversity of European freshwater systems.

Descrizione progetto (Article)

Freshwater environments are extremely sensitive to changes in meteorological conditions and the organisms they contain may be vulnerable to predicted future climate change. Aquatic ecosystems and biodiversity can also be threatened by non-native species introduced into Europe either by accident or design.

An increase in extreme weather events such as flash floods due to global warming raises the risk of non-native species reproducing and dispersing into the freshwater environment. A changing climate will put additional stress on native organisms, which are already under duress from alien species due to predation, competition for food and the introduction of new diseases.

The European-funded Alienfish&climchange project determines the risks and impacts presented by non-native fish under conditions of climate change. A scientist funded by the Marie Curie Intra-European Fellowship has assessed the risk posed by the pumpkinseed (Lepomis gibbosus) and estimated spawning frequency, growth and dispersal rates as a result of flood events. Drift nets were used to sample populations in the wild and study their reproductive strategy.

Pumpkinseed reproduction and the corresponding increase in the species' invasiveness were investigated under controlled conditions. For six months fish were held in artificial ponds; three ponds were heated by 2-3 degrees centigrade and three were at ambient temperature. Fish kept in the heated ponds spawned earlier and for longer, leading to a higher number of larger young fish and better survival rates over winter. The findings suggest that L. gibbosus will become more invasive under warmer climatic conditions.

It is crucial to understand the environmental biology of alien species if an eradication programme is to be developed to help conserve native fish. Data from Alienfish&climchange will help environmental managers and government bodies make informed decisions regarding non-native species such as pumpkinseed fish.