Changes in community composition are also happening within ecosystem types. Duque et al.  showed a change in the composition of northern Andean forests, and Feeley et al.  showed such a change in that of forests up to 2800 m in Costa Rica. In both cases the proportion of species adapted to warmer conditions increased, driven primarily by patterns of mortality, indicating that the changes in composition are mostly via range retractions, rather than range shifts or expansions. An analysis of 200 forest inventory plots in the Andes likewise indicated a widespread, though not ubiquitous, thermophilisation of tree species' composition . Within a period of 8 years , significant shifts in communities of vascular plants, butterflies and birds were found in Switzerland . At lower elevations, communities of all species groups changed towards warm-dwelling species, corresponding to an average uphill shift of 8 m, 38 m and 42 m in plant, butterfly and bird communities respectively. However, rates of community change decreased with elevation in plants and butterflies, while bird communities shifted towards warm-dwelling species at all elevations .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report