Management intensity affects the relationship between non-native and native species in subtropical wetlands

Authors


  • Boughton, E.H. (corresponding author, eboughton@archbold-station.org) & Quintana-Ascencio, P.F. (pquintan@mail.ucf.edu): Department of Biology, University of Central Florida, 4000 Central Florida Boulevard, Orlando, FL 32816, USA
    Nickerson, D. (nickersn@mail.ucf.edu): Department of Statistics and Actuarial Science, University of Central Florida, 4000 Central Florida Blvd, PO Box 162370, Orlando, FL 32816, USA
    Bohlen, P.J. (pbohlen@mail.ucf.edu): MacArthur Agro-ecology Research Center, 300 Buck Island Ranch Road, Lake Placid, FL 33852, USA

  • Co-ordinating Editor: Beth Middleton

Abstract

Question: Does management intensity affect the association between non-native and native species and between non-native species and soil nutrients in wetlands?

Location: MacArthur Agro-Ecology Research Center, Florida, USA.

Methods: We evaluated native and non-native plant richness and relative frequency in 15 1-m2 plots in 40 wetlands across two types of pastures, highly managed (fertilized, ditched, planted, heavily grazed by cattle) and semi-natural (unfertilized, lightly seasonally grazed). Plant biomass was collected in five 0.25-m2 plots per wetland and sorted to species. Soil cores were collected to analyse soil total nitrogen (N) and phosphorus (P). An information-theoretic approach was used to compare mixed effects models considering the association of non-native richness, relative frequency, and biomass with native richness, relative frequency, biomass, C3 grass relative frequency (a dominant native group), N, P and wetland-type.

Results: Non-native richness was negatively correlated with native richness in semi-natural wetlands, but there was no evidence of an association between these variables in highly managed wetlands. Non-native richness increased with increasing soil N in semi-natural wetlands, but not in the highly managed wetlands. Soil P was positively related to non-native frequency in semi-natural wetlands but negatively related in highly managed wetlands. Non-native frequency and biomass were negatively related to relative frequency of C3 grasses in both management types.

Conclusions: Our results indicate that management intensity influences relationships between native and non-native richness. Management intensity interacts with abiotic or biotic factors, such as soil nutrients and composition, in predicting where non-native species will most likely need control.

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