Ecological Archives E096-020-A3

Carol M. Frost, Raphael K. Didham, Tatyana A. Rand, Guadalupe Peralta, and Jason M. Tylianakis. 2015. Community-level net spillover of natural enemies from managed to natural forest. Ecology 96:193–202. http://dx.doi.org/10.1890/14-0696.1

Appendix C. Taxonomic composition of specialist predators moving across the habitat edge.

We used Primer 6 Version 6.1.11 with Permanova+ Version 1.0.1 to analyze the taxonomic composition of the specialist predators (parasitoids) collected in flight intercept traps. We ran two analyses. In the first, we square-root-transformed the trap count data, and calculated Bray Curtis similarity between samples. In the second, we converted the counts to presence/absence and calculated Jaccard similarity. The second analysis was to increase the weighting of rare species relative to abundant species, as compared to the first analysis, in order to see whether the results were sensitive to the weighting (Anderson 2008). In both analyses, we then ran a PERMANOVA, in which we used Type I sums of squares, permutation of residuals under a reduced model, fixed effects sum to zero for mixed terms, with 4999 permutations (Anderson 2008). We included site first, as a random factor, followed by sampling effort as a fixed effect, and then forest type (native vs. plantation) as a fixed effect. In both analyses, trapped parasitoid taxonomic composition was not significantly affected by forest type (Tables C1, C2.)

Table C1. PERMANOVA table of results when the Bray Curtis similarity metric was used for square-root-transformed trap sample data.

Table C2. PERMANOVA table of results when the Jaccard similarity metric was used for presence/absence-transformed trap sample data.

Literature cited

Anderson, M. J., R. N. Gorley, and K. R. Clarke. 2008. PERMANOVA+ for PRIMER: Guide to Software and Statistical Methods. University of Auckland, Auckland.

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