Modelling of non-native fish species responses to climate change (ALIENFISH&CLIMCHANGE)

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:
- Assess pumpkinseed growth and reproductive traits in nature (using methods currently employed for the species);
- 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);
- Determine pumpkinseed dispersal rates from floodplain water bodies into receiving streams (using drift nets to estimate propagule pressure); no information available.

The experiments revealed that pumpkinseed fish are likely to become more invasive in the UK under warmer climatic conditions. On-going field samples indicated a link between pumpkinseed dispersal and the establishment of new populations, with pumpkinseed in the UK expected to shift form non-invasive to invasibe under the predited warmer climatic consitions. There were indications for a risk of dispersal of alien fish species under the more variable discharge regimes predicted for climate change.