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 96:193202. 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.

Source

df

SS

MS

Pseudo-F

P(perm)

Unique permutations

Site

7

23243

3320.4

2.17

0.1717

2367

Sampling effort

5

10700

2139.9

1.40

0.1976

4980

Forest type

1

2001.8

2001.8

1.31

0.2625

252

Residual

2

3053.7

1526.8

 

 

 

Total

15

38998

 

 

 

 

 

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

Source

df

SS

MS

Pseudo-F

P(perm)

Unique permutations

Site

7

27466

3923.7

1.46

0.3176

2336

Sampling effort

5

14717

2943.3

1.10

0.3932

4972

Forest type

1

3007.7

3007.7

1.12

0.2982

244

Residual

2

5367.1

2683.5

 

 

 

Total

15

50557

 

 

 

 

 

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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