Abstract:
Benthic macroinvertebrate community structure was studied with respect to stream habitat type in two lowland tropical streams. Three reaches along the Carbon river and two within the Gandoca stream were chosen as study sites in Talamanca, Costa Rica. Macroinvertebrates were collected from four habitat types: leaf packs in riffles, cobble in rimes, areas of sand in pools, and areas of gravel in pools. Communities were dominated by insects in the orders Ephemeroptera (Thraulodes, Baetis?), Diptera (Chironomidae, Tipulidae), Trichoptera (Hydropsychidae, Glossosomatidae, Hydroptilidae, Calamoceratidae), and Odonata(Progomphus, Hetaerina). Noninsect macroinvertebrates were dominated by shrimps (Macrobrachium) and snails (Gastropoda). Functional feeding group composition was dominated by collector-gatherers. In most reaches, both habitat types in rimes supported higher macroinvertebrate abundance and biomass than did habitats in pools. Leaf packs in rimes represent an important habitat that is present year-round in these aseasonal tropical systems. Community composition and diversity were similar to that reported for other areas of Central America.

Author Keywords:
community structure, abundance, diversity, biomass, leaf pack habitats, riffle habitats, Talamanca

KeyWords Plus:
LEAF-LITTER, INSECTS, COMMUNITIES, RIVER, MICRODISTRIBUTION, INVERTEBRATES, DECOMPOSITION, DIVERSITY, BREAKDOWN, DETRITUS

Addresses:
Ramirez A, Univ Georgia, Inst Ecol, Athens, GA 30602 USA
Univ Georgia, Inst Ecol, Athens, GA 30602 USA

Publisher:
REVISTA DE BIOLOGIA TROPICAL, UNIVERSIDAD DE COSTA RICA CIUDAD UNIVERSITARIA, SAN JOSE, COSTA RICA

IDS Number:
214BC

ISSN:
0034-7744