Data from: Which landscape size best predicts the influence of forest cover on restoration success? – A global meta-analysis on the scale of effect

Landscape context is a strong predictor of species persistence, abundance
and distribution, yet its influence on the success of ecological
restoration remains unclear. Thus, a primary question arises: which
landscape size best predicts the effects of forest cover on restoration
success? To answer this question, we conducted a global meta-analysis for
biodiversity (mammals, birds, invertebrates, herpetofauna and plants) and
measures of vegetation structure (cover, density, height, biomass and
litter). Response ratios were calculated for comparisons between reference
(e.g. old-growth forest) and disturbed sites (degraded or restored). Using
an information-theoretic approach, mean response ratio (restoration
success) and response ratio variance (restoration predictability) within
each study landscape were regressed against the percentage of overall
(summed forest cover) and contiguous (summed pixels of ≥60% forest cover)
forest within eight different buffer sizes of radius 5–200 km (at 1-km
resolution). We included 247 studies encompassing 196 study landscapes and
4360 quantitative comparisons. The best buffer (landscape) size varied for
the following: (i) overall and contiguous forest cover, (ii) biodiversity
and vegetation structure and (iii) mean response ratio and response ratio
variance. Only plant biodiversity was influenced by overall forest cover
(buffer size of 5, 10 and 200 km radii), while plants (10 and 200 km
radii), mammals (5, 10 and 50–200 km radii), invertebrates (5 and 10 km
radii), cover (5 km radii), height (5 km radii) and litter (100 km radii)
were influenced by contiguous forest cover. Overall, mean response ratio
and response ratio variance were positively and negatively nonlinearly
related with both overall and contiguous forest cover, respectively. We
reveal for the first time a clear pattern of increasing restoration
success and decreasing uncertainty as contiguous forest cover increases.
We also indicate preliminary recommended buffer sizes for investigating
landscape restoration effects on biodiversity and vegetation structure.
However, the coarse grain and variability in the data mean the optimal
landscape size may not have been detected; thus, further research is
needed. Synthesis and applications. When setting targets for ecological
restoration, policymakers and restoration practitioners should account for
the following: (i) the landscape context, particularly the amount of
contiguous habitat up to 10 km around a disturbed site, and (ii) the
uncertainty in restoration success, as it increases when contiguous forest
cover falls below about 50%.