Abstract:
The benthic macroinvertebrate community of streams draining the south-Caribbean coast of Costa Rica, was studied to determine community structure and composition through time (September 1995 - May 1996), the effect of vegetation cover on drainage area (forest vs. disturbed sites) and to compare two sampling methods; Surber and kitchen sieve. Five sites, predominantly with a forest cover drainage area, show abundances (mean=157.60 indivs./m(2)) and taxa richness (mean=9.65 spp./m(2)) significantly higher than those found in the disturbed drainage areas (means=82.08 and 4.62 respectively). All sites have high community heterogeneity indices (> 0.80) which, together with the low similarity indices (< 0.40) between sampling times indicate a macroinvertebrate community subject to frequent disturbance events that diminish species permanence in the aquatic system. The kitchen sieve sampling method with ten replicates (4 000 cm(2)) is significantly more effective in sampling the community in terms of abundance (mean=165.10) than the traditional Surber sampler (mean=83.03) using three replicates (3 333 cm(2)). Both are equally effective in the number of taxa collected, although each device captures different ta,va. The species similarity between the Surber and the sieve method ranges between 0.1379 to 0.7619 when combining all sampling times.

Author Keywords:
streams, community structure, tropical Caribbean, sampling method, macroinvertebrates, Costa Rica, richness

KeyWords Plus:
EQUILIBRIUM

Addresses:
Paaby P, Univ Costa Rica, CIMAR, Ctr Invest Ciencias Mar & Limnol, San Jose 2060, Costa Rica
Univ Costa Rica, CIMAR, Ctr Invest Ciencias Mar & Limnol, San Jose 2060, Costa Rica

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

IDS Number:
214BC

ISSN:
0034-7744