Research Output

Inter-population dispersal of adult stoneflies detected by stable isotope enrichment.

  1. Dispersal of adult stream insects may be of considerable importance in regional population dynamics and colonisation of new sites, but quantifying the rate and extent of dispersal is difficult.

2. We used stable isotope (15N) enrichment to mark more than 1.5 million larval stoneflies (Leuctra inermis) before they emerged from an upland stream in the Plynlimon area of mid-Wales, in order to determine directly the rate and pattern of inter-site dispersal.

3. A small number of isotopically enriched adult stoneflies were captured in samples taken at adjacent streams between 800m and 1.1km away from the source population, including a headwater of a different river system.

4. The distribution of marked individuals suggested that wind influences dispersal direction in the uplands, but the low number of captures limits our ability to draw firm conclusions.

5. This is the first direct demonstration of dispersal of insects between streams. The dispersal distances recorded were significantly greater than those suggested by previous direct studies, but much more consistent with indirect studies based on genetic differentiation of populations.

Citation

Briers, R. A., Gee, J. H. R., Cariss, H. M. & Geoghegan, R. (2004). Inter-population dispersal of adult stoneflies detected by stable isotope enrichment. Freshwater Biology. 49, 425-431. doi:10.1111/j.1365-2427.2004.01198.x. ISSN 0046-5070

Authors

Keywords

Dispersal patterns; Flight; Leuctridae; Nitrogen isotope 15N; Distribution; Plecoptera studies; Comparison; Winds significant;

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