Comparing latitudinal and upstream–downstream gradients: life history traits of invasive mosquitofish
Article first published online: 1 FEB 2011
© 2011 Blackwell Publishing Ltd
Diversity and Distributions
Volume 17, Issue 2, pages 214–224, March 2011
How to Cite
Carmona-Catot, G., Benito, J. and García-Berthou, E. (2011), Comparing latitudinal and upstream–downstream gradients: life history traits of invasive mosquitofish. Diversity and Distributions, 17: 214–224. doi: 10.1111/j.1472-4642.2011.00743.x
- Issue published online: 16 FEB 2011
- Article first published online: 1 FEB 2011
- Biological invasions;
- invasive species;
- life history;
- reproductive investment;
Aim Variation of life history traits along spatial gradients is poorly understood in invasive species and particularly in freshwater fish. We aimed to examine life history variation in a highly invasive fish (Gambusia holbrooki) along latitudinal and upstream–downstream river gradients and to assess the effects of age on this variation. We hypothesized similar responses in populations inhabiting environments more favourable to this species (lower latitudes and lower reaches of rivers).
Location European rivers from southern Spain to southern France.
Methods We sampled mosquitofish from the lowest reaches of ten river basins along 6° of latitude in the Mediterranean region and seven sites along the upstream–downstream gradient in three of the rivers. We examined abundance, population structure, size-at-age and other life history traits along these gradients.
Results As hypothesized, lower reaches and lower latitudes both resulted in higher reproductive effort and lower body condition of mosquitofish. However, these patterns explained low per cent variation, were nonlinear and strongly depended on fish age. Independently of fish size, age groups differed in reproductive effort, in the gonadal weight–size relationship and its variation along spatial gradients. Mean size-at-age (or overall body size) did not vary with latitude (so the intra-specific version of Bergmann’s rule or its converse does not apply) and in contrast increased upstream in rivers.
Main conclusions Our findings suggest that for life history traits of freshwater organisms, river longitudinal variation plays a role as important as climate, with often differential effects. Our results also illustrate the poor knowledge of spatial variation of many life history traits, which precludes the understanding and prediction of biological invasions in a rapidly changing world.