A new global review of observed climate change impacts on plant communities reveals major gaps in where and how we monitor some of the world's most climate-vulnerable ecosystems.
Mediterranean-type ecosystems (MTEs) occur in five regions globally: the Mediterranean Basin, California, central Chile, southwestern Australia and South Africa. Recognised for their exceptional biodiversity and endemism, these ecosystems are also experiencing substantial climate pressures. Yet a systematic review by researchers from the University of Cape Town and the South African Environmental Observation Network reveals that evidence of how their plant communities are responding to climate change remains uneven.
The researchers identified 128 studies meeting their criteria, with only 9% conducted in the Global South. The study, published in Ecological Solutions and Evidence, was led by Hana Petersen, with Ryan Blanchard and Jasper Slingsby.
“Much of what we know about the future of Mediterranean-type ecosystems comes from models and experiments,” says Petersen. “But observations of what is actually happening in natural plant communities are much less common, and the observations we do have are not evenly distributed around the world.”
All five Mediterranean-type ecosystems experience hot, dry summers and cooler, wetter winters, and support globally important biodiversity. The IPCC has reported extreme droughts across all five regions in recent decades, including particularly severe events in South Africa and California. The review found that only 11 of the 128 studies were represented in IPCC assessment reports. Evidence was also strongly geographically biased, limiting our ability to distinguish genuine ecological differences between regions from differences arising from where research has been conducted.
“This geographical imbalance matters because it limits how confidently we can generalise from one MTE region to another,” says Slingsby. “A response documented extensively in California or the Mediterranean Basin may not necessarily tell us how vegetation will respond in the Cape Floristic Region, for example.”
The most frequently reported disturbances were climate variability, drought, wildfire, frost, and pathogens or insect infestations. Most studies examined vegetation condition and growth, while far fewer investigated plant diversity, phenology or physiology. Some response types were not represented in particular regions. Although confidence was relatively high in evidence linking climate change-related disturbances to vegetation responses, it was lower when studies attempted to demonstrate that climate change itself had caused observed biological changes.
“Seeing that vegetation has changed at the same time as climate has changed does not necessarily tell us that climate change caused that vegetation change,” explains Blanchard. “There can be many other factors involved, including fire, land use, herbivory, invasive species and natural ecological variability.”
Few observational studies included in the review used modern causal inference approaches to distinguish climate change effects from other drivers. The researchers argue that this gap presents an opportunity to make better use of existing ecological data, including through reanalysis of historical datasets. The authors advocate coordinated research across all five MTEs, integrating long-term monitoring, existing observational datasets, remote sensing, experiments and causal inference methods.
“This is not simply a matter of filling gaps on a map,” says Petersen. “We need to understand whether the mechanisms driving resilience in one region can help us anticipate what will happen in another.”
A coordinated approach could strengthen understanding of climate-driven vegetation change and support conservation planning and climate adaptation in some of the world's most important biodiversity hotspots.
Ecological Solutions and Evidence
Systematic review
Not applicable
A systematic review of observational studies reporting climate change impacts on plant communities in Mediterranean-type ecosystems
4-Aug-2026
The authors declare no conflict of interest.