David Bass

Application of Island Biogeography Theory to Temporary Pools

Abstract One aspect of island biogeography theory contends that a direct correlation exists between the size of an island and the species richness of an island. We applied this aspect of island biogeography theory to temporary pools. Six temporary pools were randomly selected and placed into three size categories based on the volume of water contained in each. The contents were filtered through a 0.250 mm sieve and retained. Invertebrates were identified, and counted. We found that species richness and the total number of individuals increased with pool size. In addition, the larger pools supported more functional feeding groups than smaller pools. These results were probably a reflection of greater microhabitat availability in the larger pools.

Colonization and succession of benthic macroinvertebrates in Arcadia Lake, a South-Central USA reservoir

Colonization and succession of benthic macroinvertebrates in Arcadia Lake, an urban reservoir, were studied for four years. Physicochemical conditions including water temperature, dissolved oxygen concentrations, pH, specific conductance, and Secchi disc depth were also recorded. Colonization of the reservoir occured fairly rapidly through a sequence of three invasions. The first, and most significant, colonists were primarily facultative species already present in streams and ponds that were inundated by the impoundment. Later arrivals tended to be limnophilic species that probably came from other bodies of water. Of 30 species encountered in a pre-impoundment collection, only six were still present three years following impoundment. Thirty-three additional benthic macroinvertebrates species invaded the area following impoundment. Dominant taxa in the reservoir included Dero nivea, Limnodrilus sp., Chaoborus punctipennis, Chironomus sp., and Procladius sp. Pollutants accumulating in this urban reservoir, including metals and pesticides, and siltation probably have kept benthic populations relatively low and possibly reduced potential species diversity.