Publications by year
2023
Trew BT, Lees AC, Edwards DP, Early R, Maclean IMD (2023). Climate-smart prioritisation of tropical Key Biodiversity Areas for protection in response to widespread temperature novelty.
Abstract:
Climate-smart prioritisation of tropical Key Biodiversity Areas for protection in response to widespread temperature novelty
Key Biodiversity Areas (KBAs) are a cornerstone of 21stcentury area-based conservation targets. In tropical KBAs, biodiversity is potentially at high risk from climate change, because most species reside within or beneath the canopy, where small increases in temperature can lead to novel climate regimes. We quantify novelty in temperature regimes by modelling hourly temperatures below the forest canopy across tropical KBAs between 1990 and 2019. We find that up to 66% of KBAs with tropical forest are likely to have transitioned to novel temperature regimes. Nevertheless, 34% of KBAs are providing refuge from novelty, 58% of which are not protected. By conducting the first pan-tropical analyses of changes in below-canopy temperatures, we identify KBAs that are acting as climate refugia and should be prioritised as candidates for expansion of the conservation network in response to the post-2020 Global Biodiversity Framework target to conserve 30% of land area by 2030.
Abstract.
Trew B, Edwards D, Lees A, Klinges DH, Early R, Svátek MM, Plichta R, Matula R, Okello J, Niessner A, et al (2023). Novel climates are already widespread beneath the world’s tropical forest canopies.
Abstract:
Novel climates are already widespread beneath the world’s tropical forest canopies.
Abstract
. Tropical forest biodiversity is potentially at high risk from climate change, but most species reside within or beneath the canopy, where they are buffered from extreme temperatures, implying that forest canopies may reduce the severity of warming impacts. Using a mechanistic microclimate model, we quantify hourly below-canopy climate conditions of 300,000 tropical forest locations globally between 1990–2019. We show that while temperature extremes are buffered below canopy, recent small increases in beneath-canopy temperature (<1ºC) have led to highly novel temperature regimes across most of the tropics. This is the case even within ecologically unfragmented areas, suggesting that tropical forests are sensitive to climate change. However, across the globe, some forest areas have experienced low climate novelty and thus serve as. important climate refugia. These areas require urgent protection and restoration. By conducting the first pan-tropical analyses of changes in below-canopy climatic conditions, we challenge the prevailing notion that tropical forest canopies reduce the severity of climate change impacts.
Abstract.
Trew B (2023). Quantifying the vulnerability of biodiversity to climate change.
Abstract:
Quantifying the vulnerability of biodiversity to climate change.
Species distribution models (SDMs) have emerged as a powerful research tool for predicting the impact of climate change on global biodiversity and are increasingly being used to guide international and local decision-making for conservation. However, the accuracy of these models is limited by their reliance on seasonally aggregated climate data derived from weather stations, which fail to reflect conditions experienced by organisms in nature. This is because climate conditions vary in multiple dimensions: geographical space, vertical space, and through time. In this thesis, I explore what this means for predicting the impact of climate change on global biodiversity. I demonstrate that the conclusions reached about where, and which species are most threatened by climate change is fundamentally altered when the discrepancy between standard climate data and conditions experienced by species is considered. In Chapter 2, I show that global diversification has, in part, been driven by spatiotemporal variation in climate, such that the most diverse regions have historically experienced relatively stable conditions and are thus more sensitive to changes that do occur. In Chapter 3, I show that the choice of near-ground or free-air temperatures to fit SDMs significantly influences which places are perceived as most vulnerable to climatic changes. In Chapters 4 and 5, I investigate the temporal and vertical dimensions of climate change and demonstrate that even modest changes can result in widespread and pervasive novel conditions across the tropics. Finally, in Chapter 6, I incorporate spatiotemporal climate gradients into SDMs to investigate whether recent climate changes have resulted in declines of climate suitability and species richness for neotropical bird species. I conclude by emphasising the need to realistically capture the conditions experienced by organisms when predicting how they are responding to climate change. My thesis demonstrates the importance of accurately capturing multi-dimensional climate gradients and considering how they are relevant to organisms when predicting the impact of climate change on global biodiversity. By doing so, predictive modelling can better inform conservation strategies to protect the most vulnerable species and regions.
Abstract.
Gardner AS, Trew BT, Maclean IMD, Sharma MD, Gaston KJ (2023). Wilderness areas under threat from global redistribution of agriculture.
Curr Biol,
33(21), 4721-4726.e2.
Abstract:
Wilderness areas under threat from global redistribution of agriculture.
Agriculture expansion is already the primary cause of terrestrial biodiversity loss globally1,2; yet, to meet the demands of growing human populations, production is expected to have to double by 2050.3 the challenge of achieving expansion without further detriment to the environment and biodiversity is huge and potentially compounded by climate change, which may necessitate shifting agriculture zones poleward to regions with more suitable climates,4 threatening species or areas of conservation priority.5,6,7 However, the possible future overlap between agricultural suitability and wilderness areas, increasingly recognized for significant biodiversity, cultural, and climate regulation values, has not yet been examined. Here, using high-resolution climate data, we model global present and future climate suitability for 1,708 crop varieties. We project, over the next 40 years, that 2.7 million km2 of land within wilderness will become newly suitable for agriculture, equivalent to 7% of the total wilderness area outside Antarctica. The increase in potentially cultivable land in wilderness areas is particularly acute at higher latitudes in the northern hemisphere, where 76.3% of newly suitable land is currently wilderness, equivalent to 10.2% of the total wilderness area. Our results highlight an important and previously unidentified possible consequence of the disproportionate warming known to be occurring in high northern latitudes. Because we find that, globally, 72.0% of currently cultivable land is predicted to experience a net loss in total crop diversity, agricultural expansion is a major emerging threat to wilderness. Without protection, the vital integrity of these valuable areas could be irreversibly lost.
Abstract.
Author URL.
2022
Trew BT, Early R, Duffy JP, Chown SL, Maclean I (2022). Using near-ground leaf temperatures alters the projected climate change impacts on the historical range of a floristic biodiversity hotspot.
DIVERSITY AND DISTRIBUTIONS,
28(6), 1282-1297.
Author URL.
2021
Trew BT, Maclean IMD (2021). Vulnerability of global biodiversity hotspots to climate change.
Global Ecology and Biogeography,
30(4), 768-783.
Abstract:
Vulnerability of global biodiversity hotspots to climate change
AbstractMotivationMore than half of Earth's species are contained in a mere 1.4% of its land area, but the climates of many of these biodiversity hotspots are projected to disappear as a consequence of anthropogenic climate change. There is growing recognition that spatio‐temporal patterns of climate in biodiversity hotspots have shaped biological diversity over a variety of historical time‐scales, yet these patterns are rarely taken into account in assessments of the vulnerability of biodiversity hotspots to future climate change. In our review, we synthesize the climatic processes that have led to the diversification of hotspots and interpret what this means in the context of anthropogenic climate change. We demonstrate the importance of mesoclimatic processes and fine‐scale topographical heterogeneity, in combination with climatic variability, in driving speciation processes and maintaining high levels of diversity. We outline why these features of hotspots are crucial to understanding the impacts of anthropogenic climate change and discuss how recent advances in predictive modelling enable vulnerability to be understood better.LocationGlobal.Main conclusionsWe contend that many, although not all, biodiversity hotspots have climate and landscape characteristics that create fine‐scale spatial variability in climate, which potentially buffers them from climatic changes. Temporally, many hotspots have also experienced stable climates through evolutionary time, making them particularly vulnerable to future changes. Others have experienced more variable climates, which is likely to provide resilience to future changes. Thus, in order to identify risk for global biodiversity, we need to consider carefully the influence of spatio‐temporal variability in climate. However, most vulnerability assessments in biodiversity hotspots are still reliant on climate data with coarse spatial and temporal resolution. Higher‐resolution forecasts that account for spatio‐temporal variability in climate and account better for the physiological responses of organisms to this variability are much needed to inform future conservation strategies.
Abstract.
2019
Trew BT, Grantham HS, Barrientos C, Collins T, Doherty PD, Formia A, Godley BJ, Maxwell SM, Parnell RJ, Pikesley SK, et al (2019). Using Cumulative Impact Mapping to Prioritize Marine Conservation Efforts in Equatorial Guinea. Frontiers in Marine Science, 6