The most common type of community change takes the form of in situ decreases in cold-adapted species and increases in warm-adapted species . This process has lead to increases of species richness on mountaintops and decreased richness at adjacent lower elevations  . While it is also expected from observed range shifts of individual species that species richness should increase along tropical/temperate ecotones and along temperate/boreal ecotones, to date this has not been well documented. Lewthwaite et al  documented a small increase in local richness across Canada for 265 species of butterflies, but the stronger effect was an homogenization across the region, with generalist species generally expanding into new sites and leading to lower Beta-diversity . In a study of 66 bumble bee species across North America and Europe, Soroye et al  did not find the expected pattern, with most sites, regardless of latitude, declining in species richness, even when individual species benefited from warming or increased precipitation at some sites. Observed shifts in community composition have consequences for species' interactions. Such indirect effects of climate change have been shown to often have greater impacts on species than the direct effects of climate itself, particularly for higher-level consumers .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report