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Stable isotopic studies of earthworm feeding ecology in tropical ecosystems of Puerto Rico
Author(s) -
Hendrix Paul F.,
Lachnicht Sharon L.,
Callaham Mac A.,
Zou Xiaoming
Publication year - 1999
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/(sici)1097-0231(19990715)13:13<1295::aid-rcm605>3.0.co;2-9
Subject(s) - earthworm , chemistry , ecology , ecosystem , tropical forest , biology
Feeding strategies of earthworms and their influence on soil processes are often inferred from morphological, behavioral and physiological traits. We used 13 C and 15 N natural abundance in earthworms, soils and plants to explore patterns of resource utilization by different species of earthworms in three tropical ecosystems in Puerto Rico. In a high altitude dwarf forest, native earthworms Trigaster longissimus and Estherella sp. showed less 15 N enrichment ( 15 N = 3–6‰) than exotic Pontoscolex corethrurus ( 15 N =7–9‰) indicating different food sources or stronger isotopic discrimination by the latter. Conversely, in a lower altitude tabonuco forest, Estherella sp. and P. corethrurus overlapped completely in 15 N enrichment ( 15 N = 6–9‰), suggesting the potential for interspecific competition for N resources. A tabonuco forest converted to pasture contained only P. corethrurus which were less enriched in 15 N than those in the forest sites, but more highly enriched in 13 C suggesting assimilation of C from the predominant C 4 grass. These results support the utility of stable isotopes to delineate resource partitioning and potential competitive interactions among earthworm species. Copyright © 1999 John Wiley & Sons, Ltd.