Island foxes exhibited higher alpha diversity than island spotted skunks across both Santa Cruz and Santa Rosa Islands
We found that bacterial richness and Shannon diversity significantly differed by species (ANOVA: richness, F= 45.179, df =1,p <0.001; Shannon diversity, F= 5.777,df =1, p= 0.018) and sequencing plate (ANOVA: richness,F= 87.182, df =2, p <0.001; Shannon diversity, F= 7.559, df =2, p <0.001), with evenness only differing by sequencing plate (ANOVA: evenness,F= 16.709, df =2, p <0.001; Figure 2; Figure S1). In contrast, island and its interaction with species did not significantly predict alpha diversity across all three measures (allp >0.05; Table S2). We further explored these patterns using pairwise t- tests implemented between species and sequencing plates (Figure S1; Table S3). Between species, skunks exhibited significantly lower richness (pairwise t- test:t =-3.872, adj.p <0.001; Figure 2 A) and lower Shannon diversity approaching significance (pairwise t- test:t = -1.696, adj.p =0.093; Figure 2 B). Between sequencing plates, plate CIF_S08 exhibited lower richness and Shannon diversity amid higher evenness compared to plates CIF_S09 and CIF_S10 (alladj.p < 0.05), which did not significantly differ from each other (all adj.p > 0.05; Figure S1; Table S3).