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).