Data extraction & quality control
The final set of 28 studies contained 101 pairwise control (unburnt) and
treatment (burnt) plots and 5311 observations, where one observation
equates to a species being present in a burnt or unburnt plot
(Appendix 2, Table S1 ). Some studies reported changes in tree
and shrub communities but used plot sizes that are widely considered too
small for accurate estimates of the species richness of these groups as
the plots could only contain one or two mature individuals of these life
forms. We thus did not include observations for calculating tree species
richness when plots were less than 100 m2, or for
shrub species richness when plots were less than 16 m2(see Mueller-Dombois et al., 2008). Most studies (n = 24; 85 %)
provided their study site’s latitude and longitude but when these were
not provided, they were obtained using the description of the study site
location and the online toolhttps://www.latlong.net/. Not
all studies provided data on species’ abundances (density or percentage
cover), so we converted data into a presence/absence matrix for each
burnt and unburnt site.
From each study, we extracted data on two fire metrics – time since
fire (number of years between the most recent fire and sampling period),
and fire type (prescribed or non-prescribed burns). We defined each site
as protected if it was within the boundaries of a protected area (IUCN
categories I to VI) as defined by the World Database on Protected Areas
(WDPA) database (UNEP-WCMC & IUCN, 2020); this was achieved using thewdpar R package version 1.3.2 (Hanson, 2020).
Biomes were classified according to Olson et al. (2001) as i) Tropical
and Subtropical Moist Broadleaf Forests (TSMBF; 5 papers & 1846
observations) ii) Tropical and Subtropical Dry Broadleaf Forests (TSDBF,
6 papers & 859 observations) iii) Tropical and Subtropical Coniferous
Forests (TSCF, 1 paper & 31 observations), iv) Tropical and Subtropical
Grasslands, Shrublands & Savannas (TSGSS, 13 papers and 2433
observations) and v) Flooded Grasslands and Savannas (FGS, 3 papers and
142 observations).