Earthworm abundance and distribution pattern in two plant communities within a subtropical wet forest of Puerto Rico

TitleEarthworm abundance and distribution pattern in two plant communities within a subtropical wet forest of Puerto Rico
Publication TypeThesis
Year of Publication1996
AuthorsGonzález, G
DegreeMaster
Number of Pages72
UniversityUniversity of Puerto Rico
CityRio Piedras
Accession NumberLUQ.204
Keywordssubtropical wet forest
Abstract

The abundance and distribution patterns of earthworms were studied in two plant communities within a subtropical wet forest in the Luquillo Experimental Forest of Puerto Rico. One plant community is dominated by Dacryodes excelsa, Manilkara bidentata, Guarea guidonea, and Sloanea berteriana and the other by Heliconia caribaea and Prestoea montana. The former is found along ridges and hillslopes and is predominantly associated with Zarzal soil series; the latter is often found in valleys where Coloso soil occurs. A litter manipulation experiment was carried out to examine the relationship between litter input and earthworm abundance in the two plant communities. Three treatments(control, litter removal, and litter addition) were randomly assigned to plots that were established near to and away from Dacryodes trees and Heliconia clones. Litterfall was collected at both locations in each of the communities. Earthworm biomass and density in the Dacryodes community were twice as high as those in the Heliconia community. Earthworm distribution was clumped in both plant communities, but more aggregated in the Heliconia community. Litterfall rate did not differ between Dacryodes and Heliconia communities. Litter Mg and Ca concentrations were lower and C/P ratio was higher in the Dacryodes than in the Heliconia community. Within Dacryodes community, earthworm density or biomass did not differ between areas near to and away from Dacryodes trees. In contrast, abundance of anecic worms was higher in areas away from than to near the Heliconia clones. Dry weight of total earthworms tended to be higher in the litter addition treatment than the control within the Heliconia community. These data indicate that the effects of litter quantity and quality on earthworm abundance vary with plant communities within the subtropical wet forest.

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