Assessing the value of the umbrella-species concept for conservation planning with meta-analysis.

The umbrella-species concept, which suggests that conservation strategies designed for one species may benefit co-occurring species, has been promoted as a framework for conservation planning. Nevertheless, there has been considerable variation in the outcome of empirical tests of this concept that has led researchers to question its value, so we used data from 15 published studies in a meta-analysis to evaluate whether conservation of putative umbrella species also conserves co-occurring species. We tested the effectiveness of putative umbrella species categorized by taxonomic group, taxonomic similarity to co-occurring species, body size, generality of resource use, and trophic level to evaluate criteria proposed to guide the selection of umbrella species.

In situ reproduction, abundance, and growth of young-of-year and adult largemouth bass in a population exposed to polychlorinated biphenyls.

We conducted a two-year field study (2000-2001) in the Housatonic River, Massachusetts (USA) to determine if we could detect in situ population-level effects on largemouth bass (Micropterus salmoides) exposed to elevated levels of polychlorinated biphenyls (PCBs). Calculated whole-body PCB concentrations in adult bass in 2002 averaged 121 mg/kg (range = 34-556 mg/kg). Polychlorinated biphenyl concentrations in young-of-year (YOY) composites in 2000 and 2002 averaged 28 mg/kg (range = 21-41 mg/kg) and 19 mg/kg (range = 16-24 mg/kg), respectively.