Influence of physical habitat management strategies on sportfish and food-web processes
The addition of habitat structures is a popular management strategy in reservoirs meant to mitigate the negative effects of passive and anthropogenic physical habitat degradation on sportfish populations and angler harvest and satisfaction. However, mechanisms linking the direct effect of habitat management strategies on reservoir food-webs, and the ability of habitat management strategies to meet objectives, remains unclear. We conducted a series of replicated pond experiments using plastic fish attractors (Artificial) and coarse woody habitat (CWH) to test hypotheses linking the direct impact of habitat material type and spatial arrangement on aquatic invertebrates and the growth, condition, and survival of largemouth bass (M. salmoides) and bluegill (L. machrochirus), independent of habitat amount. Patterns of invertebrate community colonization and daily secondary production were similar between ponds containing Artificial or CWH structures. Moreover, the growth, condition, and survival of largemouth bass and bluegill sunfish were similar in ponds containing Artificial or CWH structures, and between ponds that differ in habitat spatial arrangement. Our results suggest that other factors such as habitat amount, or the presence of alternative physical habitats, are more important to fishes and aquatic invertebrates than habitat material type or spatial arrangement. Management agencies and stakeholders should focus on maintaining existing physical habitat abundance and diversity, and the relative cost and longevity of introducing different physical habitat types at the appropriate spatial extent may be more important than habitat material type or spatial arrangement.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign