Guy F. Midgley

Bio: Guy F. Midgley is an academic researcher from Stellenbosch University. The author has contributed to research in topics: Climate change & Biodiversity. The author has an hindex of 66, co-authored 217 publications receiving 30649 citations. Previous affiliations of Guy F. Midgley include University of Cape Town & International Union for Conservation of Nature and Natural Resources.

Ecological impacts: Variance and ecological transitions

Abstract: Rainfall variability could be a key determinant of the diverse spatial patterns of tree cover in the tropics.

No going back for species and ecosystems

Abstract: These are times both terrible and exhilarating, and for none more than conservation biologists. We are confronted by compound pressures on biodiversity worse than any seen before in human history, and our ability to respond is limited not only by a collective failure of vision, but also by economic, social and political turbulence. We are increasingly conscious of at least one window of opportunity, a coherent global response to climate change, shutting faster than we can leap through. As we know, we are the first generation able to understand the changes we have caused, but the last with the chance to influence the course of many of them [2].

Combined impacts of future climate‐driven vegetation changes and socioeconomic pressures on protected areas in Africa

Abstract: Africa's protected areas (PAs) are the last stronghold of the continent's unique biodiversity, but they appear increasingly threatened by climate change, substantial human population growth, and land‐use change. Conservation planning is challenged by uncertainty about how strongly and where these drivers will interact over the next few decades. We investigated the combined future impacts of climate‐driven vegetation changes inside African PAs and human population densities and land use in their surroundings for 2 scenarios until the end of the 21st century. We used the following 2 combinations of the shared socioeconomic pathways (SSPs) and representative greenhouse gas concentration pathways (RCPs): the “middle‐of‐the‐road” scenario SSP2–RCP4.5 and the resource‐intensive “fossil‐fueled development” scenario SSP5–RCP8.5. Climate change impacts on tree cover and biome type (i.e., desert, grassland, savanna, and forest) were simulated with the adaptive dynamic global vegetation model (aDGVM). Under both scenarios, most PAs were adversely affected by at least 1 of the drivers, but the co‐occurrence of drivers was largely region and scenario specific. The aDGVM projections suggest considerable climate‐driven tree cover increases in PAs in today's grasslands and savannas. For PAs in West Africa, the analyses revealed climate‐driven vegetation changes combined with hotspots of high future population and land‐use pressure. Except for many PAs in North Africa, future decreases in population and land‐use pressures were rare. At the continental scale, SSP5–RCP8.5 led to higher climate‐driven changes in tree cover and higher land‐use pressure, whereas SSP2–RCP4.5 was characterized by higher future population pressure. Both SSP–RCP scenarios implied increasing challenges for conserving Africa's biodiversity in PAs. Our findings underline the importance of developing and implementing region‐specific conservation responses. Strong mitigation of future climate change and equitable development scenarios would reduce ecosystem impacts and sustain the effectiveness of conservation in Africa.

Food Security: The Challenge of Feeding 9 Billion People

Abstract: Continuing population and consumption growth will mean that the global demand for food will increase for at least another 40 years. Growing competition for land, water, and energy, in addition to the overexploitation of fisheries, will affect our ability to produce food, as will the urgent requirement to reduce the impact of the food system on the environment. The effects of climate change are a further threat. But the world can produce more food and can ensure that it is used more efficiently and equitably. A multifaceted and linked global strategy is needed to ensure sustainable and equitable food security, different components of which are explored here.

Novel methods improve prediction of species' distributions from occurrence data

Abstract: Prediction of species' distributions is central to diverse applications in ecology, evolution and conservation science. There is increasing electronic access to vast sets of occurrence records in museums and herbaria, yet little effective guidance on how best to use this information in the context of numerous approaches for modelling distributions. To meet this need, we compared 16 modelling methods over 226 species from 6 regions of the world, creating the most comprehensive set of model comparisons to date. We used presence-only data to fit models, and independent presence-absence data to evaluate the predictions. Along with well-established modelling methods such as generalised additive models and GARP and BIOCLIM, we explored methods that either have been developed recently or have rarely been applied to modelling species' distributions. These include machine-learning methods and community models, both of which have features that may make them particularly well suited to noisy or sparse information, as is typical of species' occurrence data. Presence-only data were effective for modelling species' distributions for many species and regions. The novel methods consistently outperformed more established methods. The results of our analysis are promising for the use of data from museums and herbaria, especially as methods suited to the noise inherent in such data improve.

Extinction risk from climate change

Abstract: Climate change over the past approximately 30 years has produced numerous shifts in the distributions and abundances of species and has been implicated in one species-level extinction. Using projections of species' distributions for future climate scenarios, we assess extinction risks for sample regions that cover some 20% of the Earth's terrestrial surface. Exploring three approaches in which the estimated probability of extinction shows a power-law relationship with geographical range size, we predict, on the basis of mid-range climate-warming scenarios for 2050, that 15-37% of species in our sample of regions and taxa will be 'committed to extinction'. When the average of the three methods and two dispersal scenarios is taken, minimal climate-warming scenarios produce lower projections of species committed to extinction ( approximately 18%) than mid-range ( approximately 24%) and maximum-change ( approximately 35%) scenarios. These estimates show the importance of rapid implementation of technologies to decrease greenhouse gas emissions and strategies for carbon sequestration.