Protected areas play a key role in the sequestration and storage of carbon from the atmosphere into ecosystems and provide refuges for threatened species and are recognized as nature-based solutions to climate change adaption and mitigation.
Climate change is pushing temperatures beyond the thermal tolerance of many species. Whether protected areas (PAs) can serve as climate change refugia for biodiversity has not yet been explored. We find that PAs of natural (seminatural) vegetation effectively cool the land surface temperature, particularly the daily maximum temperature in the tropics, and reduce diurnal and seasonal temperature ranges in boreal and temperate regions, as compared to nonprotected areas that are often disturbed or converted to various land uses. Moreover, protected forests slow the rate of warming more at higher latitudes. The warming rate in protected boreal forests is up to 20% lower than in their surroundings, which is particularly important for species in the boreal where warming is more pronounced. The fact that nonprotected areas with the same type of vegetation as PAs show reduced warming buffer capacity highlights the importance of conservation to stabilize the local climate and safeguard biodiversity.
Protected areas (PAs) have long been used for conserving biodiversity and maintaining ecosystem services. They can provide relatively undisturbed habitats to protect threatened and endangered species. Land conservation practices around PAs have shown to effectively reduce deforestation (1) and buffer rapid agricultural and urban expansion (2). Without legal protection, natural vegetation in nonprotected areas (NPAs) is often disturbed or converted to various forms of land use, which constitutes the major threat to biodiversity (3). Land disturbance and conversion not only result in habitat and biodiversity loss but also affect Earth’s climate (4, 5) and increase the occurrence of climate extremes (6). Climate change and increased occurrences of climate extremes, particularly hot episodes, are pushing a growing number of animal and plant species toward local extinction when temperatures exceed their thermal tolerance limits (7, 8).
PAs play a key role in the sequestration and storage of carbon from the atmosphere into ecosystems and provide refuges for threatened species and are recognized as nature-based solutions to climate change adaption and mitigation (9–11). The aim of nature climate solutions to stabilize climate warming at the global scale is to make use of the characteristics of healthy ecosystems to increase carbon storage and cut greenhouse gas emissions while also enhancing biodiversity (12, 13). Globally, more than 16% of the land area is currently protected, and this stores between 12 and 16% of land carbon stocks (14, 15). Land-use change in these PAs, especially in forests, can have substantial effects on the global mean temperature, not only via enhanced greenhouse effects but also via nonlocal biogeophysical climate feedbacks. These nonlocal effects on global mean temperature can be substantial (16, 17).
However, biodiversity and its response to climate change are largely determined by microclimate that is modulated by local habitats and landscape features at the local scale (18–20). The modified landscapes have complex impacts on the local land surface and air temperatures through altered evapotranspiration (ET), surface albedo, and aerodynamic resistances (21–23). Land conversion from natural vegetation to croplands, which has been shown to have a net warming effect in the tropics, may have a neutral or net cooling effect in northern latitudes (24). However, the potential of PAs to maintain microclimate at local scales and buffer habitats from anthropogenic climate change has, so far, not been explored globally.
Here, we quantify the effects of terrestrial PAs on thermal habitats at the local scale across five major biomes, i.e., boreal (evergreen needleleaf), temperate (deciduous broadleaf), and tropical (evergreen broadleaf) forests; grasslands; and savannas. According to the 2018 World Database on Protected Areas (WDPA) (25) and Moderate Resolution Imaging Spectroradiometer (MODIS) land cover classification of 2018 (26), these five biomes account for about 63% of the global PA network and 79% of the terrestrial PAs with natural or seminatural vegetation (Fig. 1A and table S1). Species richness and abundances are often much higher inside PAs than that outside for many species (27), although the effectiveness of management in PAs can be compromised by external pressures and inadequate government support in some regions (10). Biological communities within PAs are assumed to be sustainably managed toward long-term conservation aims, and their conditions are considered to be optimal under the current climate state. NPAs of the same natural or seminatural vegetation and climate as nearby PAs are expected to experience more pressures than PAs. Our results demonstrate that PAs tend to have larger leaf area index (LAI) values than the NPAs, characterizing higher amount of foliage in the canopy that drives physiological and biophysical processes (fig. S1).
This is an excerpt from a research article by XIYAN XU, ANQI HUANG, ELISE BELLEPIETER DE FRENNE and GENSUO JIA published earlier by Science.org.