Editing IPCC:AR6/WGII/Chapter-2 (section)

===== 2.4.4.2.5 Observed changes in post-fire vegetation =====

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Globally, fire has contributed to biome shifts ( [[#2.4.3.2|Section 2.4.3.2]] ) and tree mortality (Sections 2.4.4.2, 2.4.4.3) attributed to anthropogenic climate change. Research since the AR5 has also found vegetation changes from wildfire due to climate change. Through increased temperature and aridity, anthropogenic climate change has driven post-fire changes in plant regeneration and species composition in South Africa ( [[#Slingsby--2017|Slingsby et al., 2017]] ), and tree regeneration in the western USA ( [[#Davis--2019b|Davis et al., 2019b]] ). In the fynbos vegetation of the Cape Floristic Region, South Africa, post-fire heat and drought and the legacy effects of exotic plant species reduced the regeneration of native plant species, decreasing species richness by 12% from 1966 to 2010 and shifting the average temperature tolerance of species communities upward by 0.5°C ( [[#Slingsby--2017|Slingsby et al., 2017]] ). In burned areas across the western USA, the increasing heat and aridity of anthropogenic climate change from 1979 to 2015 pushed low-elevation ponderosa pine ( ''Pinus ponderosa'' ) and Douglas fir ( ''Pseudotsuga menziesii'' ) forests across critical thresholds of heat and aridity that reduced the post-fire tree regeneration by half ( [[#Davis--2019b|Davis et al., 2019b]] ). In the southwestern USA, where anthropogenic climate change has caused drought ( [[#Williams--2019|Williams et al., 2019]] ) and increased wildfire ( [[#Abatzoglou--2016|Abatzoglou and Williams, 2016]] ), high-severity fires have converted some forest patches to shrublands ( [[#Barton--2018|Barton and Poulos, 2018]] ). Field evidence shows that anthropogenic climate change and wildfire, together, altered vegetation species composition in the southwestern USA and Cape floristic region, South Africa, reducing post-fire natural regeneration and species richness of tree and other plant species, between 1966 and 2015, at GMST increases of 0.3°C–0.9°C ( ''medium evidence'' , ''high agreement'' ).

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