TS.B.1.2 Observed responses of species to climate change have altered biodiversity and impacted ecosystem structure and resilience in most regions . Range shifts reduce biodiversity in the warmest regions and locations as adaptation limits are exceeded . Simultaneously, these shifts homogenise biodiversity  in regions receiving climate-migrant species, alter food webs and eliminate the distinctiveness of communities . Increasing losses of habitat-forming species such as trees, corals, kelp and seagrass have caused irreversible shifts in some ecosystems and threaten associated biodiversity in marine systems . Human-introduced invasive  species can reduce or replace native species and alter ecosystem characteristics if they fare better than endemic species in new climate-altered ecological niches . Such invasive species effects are most prominent in geographically constrained areas, including islands, semi-enclosed seas and mountains, and they increase vulnerability in these systems . Phenological shifts increase the risks of temporal mismatches between trophic levels within ecosystems , which can lead to reduced food availability and population abundances  and can further destabilise ecosystem resilience.  
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report