Surface indicators are correlated with soil multifunctionality in global drylands

Abstract

1. Multiple ecosystem functions need to be considered simultaneously to manage and protect the several ecosystem services that are essential to people and their environments. Despite this, cost effective, tangible, relatively simple and globally relevant methodologies to monitor in situ soil multifunctionality, that is, the provision of multiple ecosystem functions by soils, have not been tested at the global scale.2. We combined correlation analysis and structural equation modelling to explore whether we could find easily measured, field-based indicators of soil multifunctionality (measured using functions linked to the cycling and storage of soil carbon, nitrogen and phosphorus). To do this, we gathered soil data from 120 dryland ecosystems from five continents.Handling Editor: Kechang Niu 3. Two soil surface attributes measured in situ (litter incorporation and surface aggregate stability) were the most strongly associated with soil multifunctionality, even after accounting for geographic location and other drivers such as climate, woody cover, soil pH and soil electric conductivity. The positive relationships between surface stability and litter incorporation on soil multifunctionality were greater beneath the canopy of perennial vegetation than in adjacent, open areas devoid of vascular plants. The positive associations between surface aggregate stability and soil functions increased with increasing mean annual temperature. Synthesis and applications.Our findings demonstrate that a reduced suite of easily measured in situ soil surface attributes can be used as potential indicators of soil multifunctionality in drylands world-wide. These attributes, which relate to plant litter (origin, incorporation, cover), and surface stability, are relatively cheap and easy to assess with minimal training, allowing operators to sample many sites across widely varying climatic areas and soil types. The correlations of these variables are comparable to the influence of climate or soil, and would allow cost-effective monitoring of soil multifunctionality under changing land-use and environmental conditions. This would provide important information for evaluating the ecological impacts of land degradation, desertification and climate change in drylands world-wide.

Loss of plant cover mediates the negative effect of anthropogenic disturbance on the multifunctionality of a dryland

“…In drylands, global studies investigating the main drivers of ecosystem multifunctionality indicate the importance climatic factors, livestock grazing and biodiversity (Gross et al, 2017;Maestre et al, 2012Maestre et al, , 2016. Nevertheless, plant cover has been shown as a strong predictor of multifunctionality in drylands (Berdugo et al, 2017;Eldridge et al, 2020). When compared to the biodiversity effects, plant cover presented stronger effects on ecosystem functioning at the global scale (Maestre et al, 2010;Soliveres et al, 2014).…”

Low‐intensity kangaroo grazing has largely benign effects on soil health

“…the ability of soils to provide multiple ecosystem functions simultaneously), in the presence of low levels of kangaroo grazing. While we did not assess soil nutrients, indirect evidence for this comes from global studies (Eldridge et al 2019) showing that two of our surface measures, litter incorporation and soil surface integrity, were two strong predictors of soil multifunctionality in drylands, after accounting for the influence of climate and soil. Our study, however, does not consider appropriate stocking rates of kangaroos in this peri-urban environment.…”

“…Within each quadrat, we assessed the status and morphology of 14 soil surface attributes, which are indicative of soil health and function (e.g. Maestre & Puche 2009;Eldridge et al 2017;Eldridge et al 2019). These features were as follows: (i) surface roughness, that is microtopography; (ii) surface hardness, that is the extent to which the surface resists deformation by erosion; (iii) surface cracking, the degree of cracking in the crust; (iv) crust stability, assessed by examining how soils break down in water; (v) soil surface integrity, that is the cover of the soil that is uneroded; (vi) surface deposited soils, that is the cover of any eroded material deposited on the soil; (vii) biological soil crust cover; (viii) plant foliage cover; (ix) plant basal cover; (x) litter cover; (xi) litter depth; (xii) litter origin, that is whether litter is local or transported from elsewhere; (xiii) the degree of litter incorporation; and (xiv) soil texture (Appendix S1).…”

Resilience, Adaptability, and Regime Shifts Thinking: A Perspective of Dryland Socio-Ecology System

“…And the related vegetation and soil characteristics of dryland rangelands across Patagonia were released this year (Oliva et al, 2020). Other studies have looked at using the correlation between the easier-collecting surface indicators and soil multi-functionality in further to conduct resilience measuring in global drylands (Eldridge et al, 2020).…”