Ecosystem Services In Drylands Research Articles

Dominant species determine grazing effects on the stability of herbaceous community production at multiple scales in drylands

Abstract Sustainable provision of critical ecosystem services in drylands is reliant on their stability under anthropogenic disturbances. Livestock grazing and shrub encroachment are the primary drivers of disturbance that impact their biodiversity and production dynamics. However, the effects of grazing on the stability at multiple scales, particularly following the transition from grass‐dominated to shrub‐encroached drylands, is still largely unexplored. Here, we conducted comparable sheep‐grazing experiments in two types of drylands (grass‐dominated vs. shrub‐encroached grasslands) on the Mongolia Plateau to explore the effects of grazing and shrub encroachment on biodiversity and stability at multiple scales. We examined how grazing affected the temporal stability of aboveground biomass in herbaceous communities in both grass‐dominated and shrub‐encroached grasslands, through two potential mechanisms: insurance effects and changes in the population‐level stability of individual species. We found that an increase in sheep grazing intensity had significant and negative effects on insurance effects by decreasing both species asynchrony and spatial asynchrony but it had no effects on population stability, consequently leading to reductions in herbaceous community stability of the grasslands. However, grazing‐increased insurance effects cancelled out grazing‐decreased population stability, contributing to no changes in the community stability of shrub‐encroached grasslands. Likely, because grazing‐induced reductions in the relative abundance of the dominant species were more noticeable in shrub‐encroached grasslands than that of in grasslands. Moreover, the grazing‐decreased abundance of dominant species was directly correlated to increases in insurance effects in shrub‐encroached grasslands but not in grasslands, despite the positive relationships between population stability and the relative abundance of the dominant species in both grass‐dominated and shrub‐encroached drylands. Synthesis and applications. Our results indicate that grazing can decrease the stability of herbaceous production in drylands but this negative effect is attenuated with the transition from grasslands to shrub‐encroached grasslands, suggesting that grazing effects on herbaceous community stability can be altered by shrub encroachment in drylands. Furthermore, the stability of dominant grasses plays a crucial role in stabilizing herbaceous communities and should be considered in promoting sustainable ecosystem functioning and services in drylands.

Determining the contribution of microbiome complexity to the soil nutrient heterogeneity of fertile islands in a desert ecosystem.

"Fertile islands" are known as hotspots of soil nutrient spatial heterogeneity in dryland ecosystems. Although soil microorganisms play critical functional roles in nutrient capture and cycling within fertile islands, our understanding of polymicrobial community roles in regulating soil nutrient distribution in fertile islands remains limited. Herein, we aim to clarify the relationships between the complexity of soil microbial (bacterial, archaeal and fungal) communities and the nutrient distribution around fertile islands. Soil samples were collected along vertical profiles at varying depths in three patches under the canopy of Hedysarum scoparium (CENTRE), at the edge (EDGE) of the canopy and outside (OUTSIDE) the canopy in an area of flowing sand. All the three microbiota have showed spatial heterogeneity around the fertile islands. Among them, bacteria had the most significant heterogeneity, and bacterial community assembly was dominated by deterministic processes. Microbial interaction patterns also showed spatial heterogeneity among different patches. More interaction complexity within microbiota was found in the bacteria in the CENTRE patch and in the fungi in the OUTSIDE patch. In addition, the proportions of among-kingdom connections were reduced under the canopies. Bacteria had the highest connectivity and centrality in the polymicrobial networks and were the most important predictor of polymicrobial interaction complexity, which may have contributed to the distribution of soil nutrients. The random forest (RF) model provided evidence that bacterial beta-diversity and the polymicrobial network complexity index can be optimal predictors of the soil multinutrient cycling index. Our study highlighted the responses of bacteria and polymicrobial interactions to fertile islands and their importance in driving soil nutrient heterogeneity. This information will help in managing soil microorganisms to provide dryland ecosystem services.

Ecologically relevant moisture and temperature metrics for assessing dryland ecosystem dynamics

AbstractIn drylands, water‐limited regions that cover ~40% of the global land surface, ecosystems are primarily controlled by access to soil moisture and exposure to simultaneously hot and dry conditions. Quantifying ecologically relevant environmental metrics is difficult in drylands because the response of vegetation to moisture and temperature conditions is not easily explained solely by climate‐based metrics. To address this knowledge gap, we developed and examined 27 climate and ecological drought metrics across dryland areas of the western United States. Included in the 27 metrics is a suite of 19 largely new “ecological drought metrics” that are designed to quantify multiple aspects of environmental limitation in drylands, including overall growing conditions, seasonal fluctuations, seasonal moisture timing, exposure to extreme drought and recruitment potential for perennial plants. To quantify these metrics, we simulated water balance pools and fluxes of daily soil moisture at multiple depths with historical weather from 1970 to 2010 using the SOILWAT2 ecosystem water balance model. We assessed the relationships among these metrics and their spatial and temporal patterns. We found that the inclusion of ecological drought metrics substantially increased the dimensionality of the climate metrics dataset; the number of independent variables needed to explain 90% of the variance in the dataset increased with the addition of ecological drought metrics. Spatial patterns in overall growing conditions represented well‐known differences among ecoregions, for example, high temperatures and low precipitation in the southwest and cool temperatures and greater precipitation in the northeast. Seasonal fluctuation in soil water availability (SWA) was greatest in the southwest (Mojave Desert), whereas fluctuation in climatic water deficit (CWD) was greatest in the northwest (northern Great Basin and Columbia Plateau). Seasonal timing of moisture also differed among metrics; the timing of wet degree days (WDD), the timing of SWA and the timing of CWD were only weakly related to seasonal timing of precipitation. Plant recruitment metrics varied strongly across western drylands. In the Great Plains, recruitment events occurred more frequently and lasted longer than in the intermountain regions, where recruitment events were comparatively rare and short. These ecological drought metrics provide new insight into patterns of soil moisture and temperature that shape the structure and function of dryland ecosystems. The metrics will be useful for assessing the potential impact of climate change on dryland ecosystems and developing adaptive resource management strategies to sustain dryland ecosystem services in a changing world.

Evaluating the influences of urban expansion on multiple ecosystem services in drylands

ContextEffectively estimating the influences of urban expansion on multiple ecosystem services (ESs) is of great importance for improving urban planning in drylands. However, there are some shortcomings in the existing urban expansion models, which lead to great uncertainties in the assessment of the influences of urban expansion on multiple ESs.ObjectivesThis study sought to effectively estimate the influences of urban expansion on multiple ESs in drylands.MethodsWe combined the land use scenario dynamics-urban model and ES models to estimate the influences of urban expansion on habitat quality, food production, water retention, air quality regulation, sand fixation, and aesthetics.ResultsThe results showed that (1) our method can effectively evaluate the influences of urban expansion on multiple ESs in drylands, and the accuracy increased by more than 20% on average. (2) Under the impacts of future urban expansion, the annual average loss per unit area of habitat quality, food production, water retention, air quality regulation, sand fixation, and aesthetics will increase. (3) Future urban expansion will occupy more cropland and grassland, which will be the main reason for the intensified degradation of multiple ESs.ConclusionsWe suggest that the local government should focus on protecting key ecosystems, especially grasslands, from urban expansion to mitigate the potential influences on multiple ESs in drylands.

Relationships Between Key Dryland Ecosystem Services: A Case Study in Ordos, China

Dryland ecosystem services (ESs) have been severely harmed by global environmental changes and increased human activities. To improve ESs, it is necessary to understand how they interact in drylands. In this study, we selected Ordos dryland, which is situated in northern China, as the study area to assess its four key ESs—food supply (FS), carbon storage (CS), water yield (WY), and habitat quality (HQ)—and to identify the hotspots of multiple ES supply. Furthermore, we studied the constraint effects between ESs in Ordos in 2000, 2010, and 2020 and used a spatial trade-off model to map the trade-off and synergy areas of ESs from 2000 to 2010 and from 2010 to 2020. The results indicated that all four ESs in Ordos increased significantly over the study period. The hotspots for the supply of multiple ESs also increased in areal extent during this period, and the state of the regional ecological environment continued to improve. The constraint effect between ESs showed that as the CS increased, its constraint effect on WY and FS decreased and then increased, whereas its constraint effect on HQ only decreased; as the WY increased, its constraint effect on HQ decreased and then increased, and its constraint effect on FS continued to decrease; as the FS increased, its constraint effect on HQ continued to increase. From the change in the area of ESs trade-offs and synergies, there was an increase in the area of positive synergy for four pairs of ESs in Ordos, which were CS-WY, CS-HQ, WY-HQ, and FS-HQ. These findings help in establishing a scientific foundation for the management and optimization of ESs in drylands.

Intermediate human activities maximize dryland ecosystem services in the long-term land-use change: Evidence from the Sangong River watershed, northwest China

Human activities cause widespread changes in landscape composition, which can affect ecosystem services produced by these landscapes. It is usually believed that ecosystem services can be maximized only when we eliminate all human activities. However, this belief is not the case, at least in dryland ecosystems. Here, a gradient of human activity intensity was used to investigate changes in the value of ecosystem services over 30-years of land-use change between 1990 and 2020 in the arid Sangong River watershed of northwest China. Spatial analyses were performed to determine how the value of dryland ecosystem services changed with human activity intensity. Stepwise regressions and linear programming models were also performed to examine how to optimize the value of ecosystem services (i.e., regulating services, provisioning services, supporting services, and cultural services). We found that landscapes of the Sangong River watershed became increasingly fragmented and that human activities gradually intensified, but the value of ecosystem services fluctuated rather than linearly decreasing over the past 30 years. Specifically, a unimodal relationship was observed between human activities and ecosystem services. The peak value of ecosystem services was 5799 USD ha−1 yr−1 under intermediate human activity intensity (i.e., human footprint index ranged from 0.2 to 0.4 at a scale of one). Gross domestic product (GDP) per capita, population, and water consumption were the three most important driving factors of human activities and ecosystem services. Our results suggest that intermediate human activities may maximize dryland ecosystem services in long-term land-use change at the watershed scale, and highlight the importance of regulating economic development, population, and water consumption for the management of dryland ecosystem services.

Editorial: Impacts of Climate Change and Land-Use on Soil Functions and Ecosystem Services in Drylands

Editorial: Impacts of Climate Change and Land-Use on Soil Functions and Ecosystem Services in Drylands

Opportunities and Challenges of Irrigated Crop Production in Dry Land Areas. Review

Irrigation development is very much needed in developing countries as it enhances land, water and labour productivity and improves use of agricultural inputs. Irrigated agriculture shows significant improvement over rainfed agriculture productivity it provides improved resilience against climate variability improves food security and enhances intensification. Also, with a depleting resource base and with stagnating productivity in irrigated areas, improving the productivity of dryland agriculture is necessary to maintain food security at the national scale.To improve the conditions for agricultural production, investments are needed in soil and water conservation to improve soil fertility, increase soil moisture and allow for supplemental irrigation in critical stages of growth.Generally, over 40 percent of the world area is categorized as dry-land developing countries where its accommodate 2.3 billion people mostly in Africa and Asia, and in these regions about one billion people rely on dry-land ecosystem services through rain-fed, irrigated farming and pastoralism. Dry-land areas are categorized by a scarcity of water, which has an impact on food production. Efficiency in irrigation system would help food production sustain especially in dry-land developing countries. Improvement in irrigation could be extended over an additional 110 million ha in dry-land developing countries, producing enough grain for millions of people where more than half of future increases in crop production are expected to come from irrigated land. There are two types of known irrigation systems, namely large-scale and small-scale irrigation. Most of the dryland developing countries are engaging in small-scale irrigation systems, as they are more affordable than those of large-scale systems, but are still capable of increasing food production. Water harvesting is one of the small-scale techniques of collecting runoff rain water for irrigation purposes and has significantly improved both the yield and reliability of agricultural production. The objective of this review is to examine the Opportunities and challenges of irrigated crop production in dry land developing countries. Ethiopia’s dryland agriculture is a high-risk, low-input enterprise for resource-poor farmers, who frequently use poor quality seed, inadequate and imbalanced fertilizers, and poor crop management practices. Consequently, crop yields are much below their demonstrated achievable potentials. Remedial measures for improving crop productivity include effective rainwater harvesting, land consolidation, improved credit facilities, better soil and water conservation, use of good quality seed, balanced nutrient management, and weed control. Keyword: crop Production, Land Irrigation and dry-land developing countries DOI: 10.7176/JAAS/71-02 Publication date: April 30 th 2021

Adaptation strategies of nomadic herders in northeast Mongolia: climate, globalisation and traditional knowledge

ABSTRACT Herders in Mongolia have adapted to changing environmental conditions over thousands of years through innovations in pasture and herd management practices, knowledge, collective institutions and mobility strategies, yet they now face unprecedented climate risks threatening their livelihoods, economies and ways of life. This paper presents the results of a study into how herder communities adapt to climate change and the potential role an ecosystem services approach could play in informing the development of effective adaptation strategies. The findings are based on semi-structured interviews with herders, key informants, focus group discussions and a survey of nomadic households in Northeast Mongolia. The benefits of pasture ecosystem services have changed considerably due to climatic and socio-economic changes in the Mongolian steppe resulting in degradation of the pastureland and water resources. The ways that traditional ecological knowledge and practices can support adaptation to climate change are explored. In particular, the seasonal movement of nomads represents a valuable form of knowledge and practice of adaptation in response to the changes in temperate dryland ecosystems. To continue to maintain mobility as part of adaptation strategies other adaptation actions are required, such as the implementation of an appropriate livestock insurance systems that addresses climate and weather risks, and restoration of dryland ecosystem services, notably through reforestation and improvement of water supplies. Further changes in the pastureland ecosystems may lead to further adaptations in nomadic livelihoods, leveraging nomadic herders’ knowledge of local ecosystem services.

Mask R-CNN and OBIA Fusion Improves the Segmentation of Scattered Vegetation in Very High-Resolution Optical Sensors.

Vegetation generally appears scattered in drylands. Its structure, composition and spatial patterns are key controls of biotic interactions, water, and nutrient cycles. Applying segmentation methods to very high-resolution images for monitoring changes in vegetation cover can provide relevant information for dryland conservation ecology. For this reason, improving segmentation methods and understanding the effect of spatial resolution on segmentation results is key to improve dryland vegetation monitoring. We explored and analyzed the accuracy of Object-Based Image Analysis (OBIA) and Mask Region-based Convolutional Neural Networks (Mask R-CNN) and the fusion of both methods in the segmentation of scattered vegetation in a dryland ecosystem. As a case study, we mapped Ziziphus lotus, the dominant shrub of a habitat of conservation priority in one of the driest areas of Europe. Our results show for the first time that the fusion of the results from OBIA and Mask R-CNN increases the accuracy of the segmentation of scattered shrubs up to 25% compared to both methods separately. Hence, by fusing OBIA and Mask R-CNNs on very high-resolution images, the improved segmentation accuracy of vegetation mapping would lead to more precise and sensitive monitoring of changes in biodiversity and ecosystem services in drylands.

Global Dryland Ecosystem Programme (Global-DEP): Australasian consultation report

Drylands occupy about 41% of Earth’s land area and are home to more than 2 billion people, at least half of whom are dependent on dryland ecosystem services for their livelihoods and wellbeing. Because drylands are by definition climatically challenged, and because so many peoples’ livelihoods depend on managing these challenges, climate and other environmental changes have the potential to impact dryland inhabitants early. Such impacts affect ecosystems and people in but also beyond drylands, for example where people are forced to migrate.

Grazing pressure interacts with aridity to determine the development and diversity of biological soil crusts in Patagonian rangelands

AbstractGrazing is directly related to land degradation and desertification in global drylands. Grazing impacts on vascular plants, reasonably well‐known, depend on its intensity and are modulated by local aridity conditions. However, we do not know how the interplay of grazing intensity and aridity affect biocrusts, topsoil assemblages dominated by cyanobacteria, lichens, and mosses that provide key ecosystem services in drylands. Here, we determined how grazing affects biomass, total cover, and richness of biocrust structural types across a regional aridity gradient in the Patagonian steppe. On average, grazing by sheep reduced biocrust biomass, total cover and richness of structural types by 55, 90, and 59%, respectively. In general, high grazing pressures had a larger impact on biocrusts than moderate or light grazing pressures. For example, biocrust cover was reduced by 85, 89, and 98% by light, moderate, and high grazing pressures, respectively. Although a slightly different response to grazing was observed under low aridity conditions, these more benign climatic conditions did not compensate for the negative effects of trampling by domestic animals on biocrusts. Nonetheless, estimated biocrust recovery rates under medium aridity conditions were faster than previously thought: it took 24, 18, and 58 years to double biocrust biomass, total cover, and richness of structural types. Sheep cannot be just removed in Patagonian rangelands because the production of meat and wool represents the main local economic activity. But landowners must consider our results to protect the ecosystem functions and services provided by biocrusts for future generations to come.

Spectral Diversity Successfully Estimates the α-Diversity of Biocrust-Forming Lichens

Biocrusts, topsoil communities formed by mosses, lichens, liverworts, algae, and cyanobacteria, are a key biotic component of dryland ecosystems worldwide. Experiments carried out with lichen- and moss-dominated biocrusts indicate that climate change may dramatically reduce their cover and diversity. Therefore, the development of reproducible methods to monitor changes in biocrust diversity and abundance across multiple spatio-temporal scales is key for evaluating how climate change may impact biocrust communities and the myriad of ecosystem functions and services that rely on them. In this study, we collected lichen-dominated biocrust samples from a semi-arid ecosystem in central Spain. Their α-diversity was then evaluated using very high spatial resolution hyperspectral images (pixel size of 0.091 mm) measured in laboratory under controlled conditions. Support vector machines were used to map the biocrust composition. Traditional α-diversity metrics (i.e., species richness, Shannon’s, Simpson’s, and Pielou’s indices) were calculated using lichen fractional cover data derived from their classifications in the hyperspectral imagery. Spectral diversity was calculated at different wavelength ranges as the coefficient of variation of different regions of the reflectance spectra of lichens and as the standard deviation of the continuum removal algorithm (SD_CR). The accuracy of the classifications of the images obtained was close to 100%. The results showed the best coefficient of determination (r2 = 0.47) between SD_CR calculated at 680 nm and the α-diversity calculated as the Simpson’s index, which includes species richness and their evenness. These findings indicate that this spectral diversity index could be used to track spatio-temporal changes in lichen-dominated biocrust communities. Thus, they are the first step to monitor α-diversity of biocrust-forming lichens at the ecosystem and regional levels, a key task for any program aiming to evaluate changes in biodiversity and associated ecosystem services in drylands.

Impacts of Agricultural Management Systems on Biodiversity and Ecosystem Services in Highly Simplified Dryland Landscapes

Covering about 40% of Earth’s land surface and sustaining at least 38% of global population, drylands are key crop and animal production regions with high economic and social values. However, land use changes associated with industrialized agricultural managements are threatening the sustainability of these systems. While previous studies assessing the impacts of agricultural management systems on biodiversity and their services focused on more diversified mesic landscapes, there is a dearth of such research in highly simplified dryland agroecosystems. In this paper, we 1) summarize previous research on the effects of farm management systems and agricultural expansion on biodiversity and biodiversity-based ecosystem services, 2) present four case studies assessing the impacts of management systems on biodiversity and ecosystem services across highly simplified dryland landscapes of the Northern Great Plains (NGP), USA, 3) discuss approaches to sustain biodiversity-based ecosystem services in drylands, and 4) present a conceptual framework for enhancing agricultural sustainability in the drylands through research, policy, economic valuation, and adaptive management. An analysis of the land use changes due to agricultural expansion within the Golden Triangle, a representative agricultural area in the NGP, indicated that the proportion of land conversion to agriculture area was 84%, 8%, and 7% from grassland, riparian, and shrubland habitats, respectively. Our results showed this simplification was associated with a potential reduction of pollination services. Also, our economic analysis projected that if 30% parasitism could be achieved through better management systems, the estimated potential economic returns to pest regulation services through parasitoids in Montana, USA alone could reach about $11.23 million. Overall, while dryland agroecosystems showed a significant loss of native biodiversity and its services, greater pest incidence, and a decrease in plant pollinator networks, these trends were moderately reversed in organically managed farming systems. In conclusion, although land use changes due to agricultural expansion and industrialized farming threaten the sustainability of dryland agroecosystems, this impact can be partially offset by coupling ecologically-based farming practices with adaptive management strategies.

Economic impacts of Prosopis spp. invasions on dryland ecosystem services in Ethiopia and Kenya: Evidence from choice experimental data

Biological invasions can induce trajectories of changes that make ecosystems fragile and less reliable in providing services and goods. Here we set out to assess the economic value of dry land ecosystem services affected by the invasive tree Prosopis, which was originally introduced in Africa and elsewhere for providing firewood, animal fodder and other services to rural people. Based on choice experiment method, we estimated the economic values of dry land ecosystem services affected by Prosopis in the heavily invaded Afar region, Ethiopia and Baringo County, Kenya. Including labor and cash contributions as payment attributes, a random parameters logit model was employed for analyzing households' preferences for the affected ecosystem services. We found that, despite the services provided by Prosopis, households from both regions were willing to pay for its management primarily driven by biodiversity and water. WTP was on average higher in Afar (USD 50.42/year) than in Baringo (USD 37.74/year), which may be because the ecosystems in Afar were less degraded prior to the invasion by Prosopis than in Baringo and that charcoal production in Afar is officially prohibited. Our results indicate that the costs imposed by the deliberately introduced Prosopis outweigh its benefits in both Afar and Baringo.

A global meta-analysis on the monetary valuation of dryland ecosystem services: The role of socio-economic, environmental and methodological indicators

Monetary valuation of dryland ecosystem services may help to increase the salience of drylands in decision making. Yet, there is no comprehensive assessment of the indicators that determine the estimated monetary values for dryland ecosystem services (hereafter: dryland value). Having compiled a database consisting of 559 observations from 66 valuation studies in drylands worldwide, this study analyzes the relative importance of local socio-economic, environmental and methodological indicators in explaining the monetary value estimates for nine dryland ecosystem services by means of a multiple regression analysis. By explicitly quantifying the effect sizes of the indicators of dryland value, we shed new light on the driving forces behind monetary valuation of dryland ecosystem services. Our results show that local socio-economic and environmental conditions are marginal in explaining dryland value, indicating that local dryland conditions are not sufficiently captured with current valuation approaches. Simultaneously, we find that methodological factors, including valuation method and study extent, heavily influence dryland value, suggesting that monetary valuation outcomes are largely determined by the selected methodology. This emphasizes the need to improve monetary valuation methods so that they better capture local dryland conditions in order to be able to serve as a meaningful tool for decision making.

Linking wind erosion to ecosystem services in drylands: a landscape ecological approach

Wind erosion is a widespread environmental problem in the world’s arid landscapes, which threatens the sustainability of ecosystem services in these regions. We investigated how wind erosion and key ecosystem services changed concurrently and what major biophysical and socioeconomic factors were responsible for these changes in a dryland area of China. Based on remote sensing data, field measurements, and modeling, we quantified the spatiotemporal patterns of both wind erosion and four key ecosystem services (soil conservation, crop production, meat production, and carbon storage) in the Mu Us Sandy Land in northern China during 2000–2013. Linear regression was used to explore possible relationships between wind erosion and ecosystem services. From 2000 to 2013, wind erosion decreased by as much as 60% and the four ecosystem services all increased substantially. These trends were attributable to vegetation recovery due mainly to government-aided ecological restoration projects and, to a lesser degree, slightly increasing precipitation and decreasing wind speed during the second half of the study period. The maximum soil loss dropped an order of magnitude when vegetation cover increased from 10% to 30%, halved again when vegetation increased from 30 to 40%, and showed little change when vegetation increased beyond 60%. Our study indicates that vegetation cover has nonlinear and threshold effects on wind erosion through constraining the maximum soil loss, which further affects dryland ecosystem services. These findings have important implications for ecological restoration and ecosystem management in dryland landscapes in China and beyond.

Differential effects of valuation method and ecosystem type on the monetary valuation of dryland ecosystem services: A quantitative analysis

The method of monetary valuation of ecosystem services has been argued to depend on the type of ecosystem under consideration and the choice of valuation method. Still, the impact of these factors has been hardly studied in a quantitative manner. This study aims to analyze the differential effects of ecosystem type and valuation method on the values estimated for ecosystem services, as well as the potential impact of these effects on aggregated values for ecosystem services. Drylands pose a highly relevant case to investigate these impacts, because they are particularly diverse in ecosystem types, the provided ecosystem services and, hence, are also expected to be estimated with various methods. Our analysis is based on a quantitative analysis of monetary estimates for ecosystem services (expressed in Int$/ha/yr) that were compiled in a comprehensive database containing 512 observations from 57 studies located in drylands worldwide. Our results reveal that the estimated values for dryland ecosystem services depended on the type of ecosystem and method under consideration. Several of these differential effects had a significant impact on the aggregated mean values for dryland ecosystem services. Cultivated lands had high mean values for provisioning services, in particular for food provision, but low values for regulating services. In dry forests, biodiversity-related services were estimated high, in contrast to semi-deserts and arid wetlands. Compared with other methods, market pricing estimated low values for climate regulation and high values for biological regulation. When values were aggregated for ecosystem services, market pricing was found to impact the mean value for climate and biological regulation significantly. Our results highlight the importance of explicit consideration of methods and ecosystem types in monetary valuation, which could lead to more accurate approximation of ecosystem service values.

Contrasting Effects of Aridity and Grazing Intensity on Multiple Ecosystem Functions and Services in Australian Woodlands

AbstractGlobal change is expected to reduce the provision of multiple ecosystem services in drylands, the largest biome on Earth. Understanding the relative importance of climate change and overgrazing on ecosystems services is critical for predicting the effects of global change on ecosystem well‐being. We generated a system‐level understanding of the effects of climate (aridity intensity) and land use intensification (herbivore grazing intensity) on four regulating ecosystem services (C‐storage, N‐availability and P‐availability, and organic matter decomposition) and one provisioning service (plant production) in wooded drylands from eastern Australia. Climate change and grazing intensity had different effects on multiple ecosystem services. Increasing aridity from 0·19 (dry subhumid) to 0·63 (arid) had consistent suppressive effects on C‐storage, N‐availability, decomposition and plant biomass services, but not on P‐availability. The magnitude of these suppressive effects was greater than any effects due to grazing. All sites showed evidence of kangaroo grazing, but the heaviest grazing was due to cattle (dung: range 0–4545 kg ha−1; mean 142 kg ha−1). Any effects of grazing on ecosystem services were herbivore specific and ranged from positive to neutral or negative. Sheep, and to a lesser extent cattle, were associated with greater N‐availability. Rabbits, however, had a greater effect on P‐availability than aridity. Our study suggests that increases in livestock grazing may fail to sustain ecosystem services because of the generally stronger negative effect of increasing aridity on most ecosystem services in our model dryland. These services are likely therefore to decline with global increases in aridity. Copyright © 2017 John Wiley & Sons, Ltd.

Agent-based modeling of complex social\u2013ecological feedback loops to assess multi-dimensional trade-offs in dryland ecosystem services

ContextRecent conceptual developments in ecosystem services research have revealed the need to elucidate the complex and unintended relationships between humans and the environment if we are to better understand and manage ecosystem services in practice.ObjectivesThis study aimed to develop a model that spatially represents a complex human–environment (H–E) system consisting of heterogeneous social–ecological components and feedback mechanisms at multiple scales, in order to assess multi-dimensional (spatial, temporal, and social) trade-offs in ecosystem services.MethodsWe constructed an agent-based model and empirically calibrated it for a semi-arid region in Northeast China, and examined ecosystem service trade-offs derived from the Sloping Land Conversion Program (SLCP), which is based on payment for ecosystem services. This paper describes our model, named Inner Mongolia Land Use Dynamic Simulator (IM-LUDAS), using the overview, design concepts, and details + decision (ODD + D) protocol and demonstrates the capabilities of IM-LUDAS through simulations.ResultsIM-LUDAS represented typical characteristics of complex H–E systems, such as secondary and cross-scale feedback loops, time lags, and threshold change, revealing the following results: tree plantations expanded by the SLCP facilitated vegetation and soil restoration and household change toward off-farm livelihoods, as expected by the government; conversely, the program caused further land degradation outside the implementation plots; moreover, the livelihood changes were not large enough to compensate for income deterioration by policy-induced reduction in cropland.ConclusionsIM-LUDAS proved itself to be an advanced empirical model that can recreate essential features of complex H–E systems and assess multi-dimensional trade-offs in ecosystem services.