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United States Department of Agriculture

Agricultural Research Service

Title: Consequences of Melaleuca quinquenervia invasion of the Florida Everglades: “Notes from the underground” with specific reference to nematodes

Authors
item Porazinska, Dorota - UFL
item Pratt, Paul
item Giblin-Davis, Robin - UFL

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 14, 2007
Publication Date: August 15, 2007
Citation: Porazinska, D.L., Pratt, P.D., Giblin-Davis, R.M. 2007. Consequences of Melaleuca quinquenervia invasion of the Florida Everglades: “Notes from the underground” with specific reference to nematodes. Journal of Nematology. 39(4): 305-312.

Interpretive Summary: We investigated the composition and diversity of nematode communities from soils dominated by the invasive tree Melaleuca quinquenervia as compared with adjacent soils supporting native non-invaded plant communities at 6 sites across the Florida Everglades over three years. Despite the significant geographical separation of the sites and their differences in soil type, hydrology, and native plant composition, there were consistent differences in nematode abundance and diversity between the tested plant communities. Out of 86 identified nematode genera, 20% were sensitive to the shift in vegetation cover. Overall effects were usually negative, although the exact direction and magnitude of change were site and year of sampling dependent. In general, total nematode abundance was reduced by 60% under Melaleuca. The most dramatic changes occurred among fungivores and herbivores, which were more abundant (>2X) under native plants than associated with Melaleuca. In addition, nematode communities under native vegetation shifted from herbivore to bacterivorous dominated nematodes under Melaleuca stands. The diversity of nematodes, measured as overall richness of nematodes (at the generic level) was 20% lower under exotic versus native plant communities. The decline of richness was particularly high for herbivorous nematodes (56%) and fungivores (30%). Along with changes in the soil nematode communities, changes in the soil chemical characteristics were also observed. While positive effects to Melaleuca were observed for soil moisture, % of Ca and Mg, the contribution of clay particles, and total soil C and N, the overall plant available concentrations of P, K, Ca, Mg as well as CEC were reduced. In conjunction with results from other studies, our data provide support for the presence of weakened plant-soil biota negative feedbacks in Melaleuca invaded habitats that might play a role in the remarkable success of this exotic plant in Florida ecosystems.

Technical Abstract: We investigated the composition and diversity of nematode communities from soils dominated by the invasive tree Melaleuca quinquenervia as compared with adjacent soils supporting native non-invaded plant communities at 6 sites across the Florida Everglades over three years. Despite the significant geographical separation of the sites and their differences in soil type, hydrology, and native plant composition, there were consistent differences in nematode abundance and diversity between the tested plant communities. Out of 86 identified nematode genera, 20% were sensitive to the shift in vegetation cover. Overall effects were usually negative, although the exact direction and magnitude of change were site and year of sampling dependent. In general, total nematode abundance was reduced by 60% under Melaleuca. The most dramatic changes occurred among fungivores and herbivores, which were more abundant (>2X) under native plants than associated with Melaleuca. In addition, nematode communities under native vegetation shifted from herbivore to bacterivorous dominated nematodes under Melaleuca stands. The diversity of nematodes, measured as overall richness of nematodes (at the generic level) was 20% lower under exotic versus native plant communities. The decline of richness was particularly high for herbivorous nematodes (56%) and fungivores (30%). Along with changes in the soil nematode communities, changes in the soil chemical characteristics were also observed. While positive effects to Melaleuca were observed for soil moisture, % of Ca and Mg, the contribution of clay particles, and total soil C and N, the overall plant available concentrations of P, K, Ca, Mg as well as CEC were reduced. In conjunction with results from other studies, our data provide support for the presence of weakened plant-soil biota negative feedbacks in Melaleuca invaded habitats that might play a role in the remarkable success of this exotic plant in Florida ecosystems.

Last Modified: 12/18/2014
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