Comparing the Invertebrate Communities and the Decomposition Dynamics Between Dead Native and Non-Native Trees in a...

A 6-year time-series study in the Western Everglades region of Florida, United States examined the influence of woody debris from two tree species on invertebrate richness, abundance, and diversity, as well as tree debris mass loss, fragmentation, and residence time. Samples of decomposing fine woody debris and coarse woody debris (CWD) from non-native Melaleuca quinquenervia (Cav.) Blake and native Pinus elliottii Englem trees were removed from a field site every six months and processed to capture data on biotic and abiotic variables. Invertebrates found within debris were identified to family. A total of 61,985 individual invertebrates from three classes, 17 orders, and 95 families were identified from all debris. Although both tree species supported similar richness and diversity of invertebrates, abundance was greater in P. elliottii CWD compared with M. quinquenervia. Mass loss and fragmentation of debris were more rapid in M. quinquenervia fine woody debris with no differences between species for CWD. Although M. quinquenervia CWD supported fewer invertebrates than P. elliottii, overall the exotic tree provided a similar resource during the decomposition phase as the native P. elliottii suggesting that, unlike when it is alive, its decomposing presence had a minimal impact on invertebrate food webs. Land managers should consider specific intervals between herbicide applications and controlled burns to decrease the magnitude of fires in areas where a significant portion of the fuel load consists of dead M. quinquenervia, knowing that the decomposing trees are providing significant resources for invertebrate communities in the meantime.