It is getting hotter in here: determining and projecting the impacts of global environmental change on drylands

Abstract

Drylands occupy large portions of the Earth, and are a key terrestrial biome from the socio-ecological point of view. In spite of their extent and importance, the impacts of global environmental change on them remain poorly understood. In this introduction, we review some of the main expected impacts of global change in drylands, quantify research efforts on the topic, and highlight how the articles included in this theme issue contribute to fill current gaps in our knowledge. Our literature analyses identify key under-studied areas that need more research (e.g. countries such as Mauritania, Mali, Burkina Faso, Chad and Somalia, and deserts such as the Thar, Kavir and Taklamakan), and indicate that most global change research carried out to date in drylands has been done on a unidisciplinary basis. The contributions included here use a wide array of organisms (from micro-organisms to humans), spatial scales (from local to global) and topics (from plant demography to poverty alleviation) to examine key issues to the socio-ecological impacts of global change in drylands. These papers highlight the complexities and difficulties associated with the prediction of such impacts. They also identify the increased use of long-term experiments and multidisciplinary approaches as priority areas for future dryland research. Major advances in our ability to predict and understand global change impacts on drylands can be achieved by explicitly considering how the responses of individuals, populations and communities will in turn affect ecosystem services. Future research should explore linkages between these responses and their effects on water and climate, as well as the provisioning of services for human development and well-being.

Carbon management in dryland agricultural systems. A review

“…Those attributes would lead to the reduction of soil susceptibility to degradation processes such as erosion and to the maintenance of agricultural productivity and ecosystem services. This last aspect is paramount to improving the livelihood of people living in drylands, over 38 % of the global human population (Maestre et al 2012).…”

A demographic approach to study effects of climate change in desert plants

“…Drylands, the largest terrestrial ecosystem (figure 1a [2,3]), are considered among the most sensitive to projected global environmental change [4]. Global circulation models project temperature increases, precipitation decreases and an increase in interannual variability in precipitation for many deserts [4].…”

Increasing aridity reduces soil microbial diversity and abundance in global drylands

“…However, we have limited knowledge of the role of climatic factors as drivers of their abundance and diversity at regional and global scales (10)(11)(12). This gap in our understanding is particularly true for drylands, areas with an aridity index (precipitation/potential evapotranspiration ratio) below 0.65 (13), which are among the most sensitive ecosystems to climate change (14). Drylands are expected to expand in global area by 11-23% by 2100 (15), experiencing increased aridity and reduced soil moisture (16).…”

“…Land degradation and desertification already affect ∼250 million people in the developing world (17). Altered climate and the growth of human populations will almost inevitably exacerbate these problems in drylands (14,17). Because the provisioning of ecosystem services essential for human development (e.g., soil fertility, food, and biomass production) heavily relies on the abundance, composition, and diversity of soil fungi and bacteria (18,19), it is Significance Climate change is increasing the degree of aridity in drylands, which occupy 41% of Earth's surface and support 38% of its population.…”