Results
Our analysis included 76 datasets – 37 invertebrate, 12 mammal, 9 bird,
9 herptile, and 9 plant metacommunities – totaling 4401 species and
1190 patches (Fig. 2). Biodiversity declined with habitat fragmentation
(SL > SS) in 19.9% of the SLOSS comparisons, showed no
response (SS = SL) in 34.7% of the comparisons, and increased with
fragmentation (SS > SL) in 45.2% of the comparisons (Fig.
2). If we consider only cases where one of the three SLOSS outcomes was
at least twice as likely to occur as the other two outcomes (i.e.,
> 66% of the comparisons), we found negative fragmentation
effects in 9 metacommunities (11.8%), no effect in 20 metacommunities
(26.3% of the sample), and positive fragmentation effects in 28
metacommunities (36.8%). Biodiversity was typically higher in sets of
many small patches than in sets of a few large patches in plants (81%
vs. < 1%), invertebrates (45.2% vs. 18.4%), birds (44.3%
vs. 17.5%), and mammals (36.7% vs. 19.5%). Conversely, biodiversity
of amphibians and reptiles was typically higher in sets of a few large
patches (21.6% vs. 48.8%).
Taxonomic identity had a significant effect on the SLOSS outcome,
explaining 19% of the variation, with variation explained increasing to
27% when including an additive effect of patch size evenness in the
model (marginal R2). The probability of observing
positive responses to fragmentation in biodiversity increased from
herptiles (βamp&rep = 7.95; SD = 3.98; z = 1.99;p = 0.04) to mammals (βmamm = 10.01; SD = 3.79; z
= 2.64; p < 0.01 ), birds (βbirds =
10.80; SD = 3.97; z = 2.72; p < 0.01 ), invertebrates,
(βinvert = 11.31; SD = 3.64; z = 3.10; p< 0.01 ), and plants (βplants = 16.46; SD =
4.19; z = 3.92; p < 0.01 ).