Hydrological Ecosystem Services Research Articles

How Experts’ Opinions and Knowledge Affect Their Willingness to Pay for and Ranking of Hydrological Ecosystem Services

To ensure that ecosystem services are included in decision-making processes, many studies have relied on expert opinions and knowledge to identify, rank, and assess willingness to pay. In this study, expert opinions according to their expertise in hydrology, ecology, and sociology were surveyed and compared in terms of (1) recognition and ranking of hydrological ecosystem services (HESs) and (2) willingness to pay for HESs. The decision-making process was also investigated, specifically the rankings of factors in experts’ plans for climate change adaptation. The experts’ recognition of and opinions concerning HESs were positively correlated at various levels with intention to pay (i.e., whether respondents were willing to pay for HESs). Most experts recognized the importance of HESs and allocated high average scores of 9.15, 8.17, and 8.41 to water yield, sediment export, and nutrient export, respectively, using a scale from 1 (least important) to 10 (most important). The percentage of sociologists (100%) exhibited greater intention to pay than those of hydrologists (70%) and ecologists (93%), respectively. Experts prioritized environmental impact over economic cost in policy decision-making, and they differed significantly by field in terms of their rankings of the functional, economic, environmental, and social considerations of decision-making. The results revealed significant differences among experts in their decision-making preferences according to their fields of knowledge. The experts of a specific study field may be more willing to pay for that than for another. Greater intellectual exchange and analysis among experts should be implemented and diverse expert opinions should be solicited in policy decision-making.

A multi-model approach for analysing water balance and water-related ecosystem services in the Ouriyori catchment (Benin)

ABSTRACT Freshwater supply remains limited in West Africa due to lack of operational governance frameworks. In this study, the Water flow and balance Simulation Model (WaSiM) and the Soil and Water Assessment Tool (SWAT) were applied in the Ouriyori catchment (14.5 km2, Benin) to assess hydrological ecosystem services (HES) in terms of service flow and service capacity using the ecosystem accounting framework. The modelling exercises indicated satisfactory goodness-of-fit coefficients greater than 75% with an absolute bias of less than 25%. The HES capacity was in general higher than the HES flow for crop and household (surface/groundwater) water supplies, indicating that the catchment can potentially supply more water under optimal storage and management conditions. Positive and negative shifts in service capacities of crop water and household supplies were observed over the simulation period. These significant results can support sustainable interventions in securing water and food productions through increasing HES flow and capacity.

De Pago por Servicios Ambientales Hidrológicos a Fondos Concurrentes: estudio de percepción social en una comunidad forestal de Oaxaca, México

Esta investigación contribuye a la discusión sobre el futuro del programa federal de Pago por Servicios Ambientales Hidrológicos (PSAH) y su posible transición hacia los Mecanismos Locales de Pago por Servicios Ambientales a través de Fondos Concurrentes (MLPSA-FC). Se desarrolló un análisis de percepción social con actores clave involucrados en el proceso de aplicación (proveedores, usuarios e intermediarios) sobre los efectos sociales, económicos y ambientales generados en una comunidad forestal de Oaxaca, México. A partir de entrevistas semiestructuradas aplicadas en 2016-2017, se identificó que los usuarios se inclinan hacia los MLPSA-FC; no obstante, los intermediarios y los proveedores prefieren el PSAH. Al parecer, la transición no se da por una decisión voluntaria, sino en un contexto de alta competitividad e insuficiencia presupuestaria para sustentar el programa federal de PSAH por parte de la Comisión Nacional Forestal (CONAFOR). En este sentido, es necesario elaborar evaluaciones de los efectos, desde un enfoque integral, de los esquemas de PSA en México, así como estudios de comparación de los efectos generados por los programas federales y los mecanismos locales desde perspectivas inter y transdisciplinarias.

Evaluating water resources management scenarios considering the hierarchical structure of decision-makers and ecosystem services-based criteria

This paper introduces a new methodology for evaluating water resources management scenarios considering different aspects of their hydrological ecosystem services. The temporal variations of supplied water to different demands are assessed as provisioning hydrological ecosystem services. Then, three agricultural drought management policies have been defined for each water supply-demand alternative to reduce the irrigation water and cultivated area of the agricultural demand nodes during droughts. In addition to the net primary productivity criterion (NPP) and economic profit, the ecological condition of the system has been evaluated as an ecosystem services-based criterion. To prioritize and select the best water resources management (WRM) scenario(s), a game theory-based hierarchical evidential reasoning (ER) technique with multiple decision-makers has been used. The proposed methodology has been applied to the Urmia Lake basin, which is the largest saline lake in the Middle East. The grade-based values of the criteria have been used to compare the WRM scenarios. The results show that a scenario that includes supplying 100% of the lake's water demand has the highest priority. This scenario also suggests reducing the cultivated area of dominant crops and using deficit irrigation practices.

The effect of future land use changes on hydrologic ecosystem services: a case study from the Zala catchment, Hungary

Maintaining and, where possible, improving the ecological status of our water resources are of particular importance for the future. So, one of the main drivers of landscape design must be to protect our waters. In this study, we carried out an evaluation of four hydrologic ecosystem services (HES) in the Zala River catchment area, the largest tributary of Lake Balaton (more than half of the lake’s surface inflow comes from the Zala River), Hungary. The lake has great ecological, economic and social importance to the country. We used the cell-based InVEST model to quantify the spatial distribution of flood control, erosion control and nutrient retention ecosystem services for phosphorus and nitrogen; then, we carried out an aggregated evaluation. Thereby, we localized the hot spots of service delivery and tested the effect of focused land use changes in critical areas of low performance on the examined four HES. Forests proved to have the best aggregated result, while croplands near the stream network performed poorly. The modelled change in land use resulted in significant improvement on nutrient filtration and moderate to minimal but improving change for the other HES in most cases. The applied method is suitable as a supporting tool at the watershed level for decision-makers and landscape designers with the aim of protecting water bodies.

Spatio-temporal quantification of patterns, trade-offs and synergies among multiple hydrological ecosystem services in different topographic basins

A comprehensive understanding of the spatio-temporal characteristics of interactions and spatial scales of multiple hydrological ecosystem services (HESs) is important for sustainable ecosystem management, but interactions among multiple HESs and their underlying mechanisms in complex socio-ecological systems in different topographic areas remain under-researched. This study discuss the spatial and temporal variation of patterns and interactions of five HESs (biodiversity maintenance, water yield, soil conservation, aquatic purification and water production) in plain and mountain regions to determine synergies and trade-offs at the sub-catchment scale and county scale from 1980 to 2015, and this study employ a case study in the western plain and eastern mountain part of the Nansihu Lake basin in eastern China. The correlation analysis and bagplot analysis were applied to analyze the linkages between HESs, and then redundancy analysis was used to identify important drivers of spatial patterns and interactions of HESs based on socio-ecological variables (e.g., climate, topography, land use, gross domestic product and population density). The results demonstrate that the intercorrelations among HESs varied significantly between the western plain and eastern mountain in both the strength and the direction of the correlating HESs. It was found that there was a trade-off between the water yield and water production in the provisioning services in the eastern mountain basin, while there was no correlation in the western plain basin. Trade-offs and synergies in the entire basin varied greatly over time and space. Compared to the sub-catchment scale, the relationships among the different HESs were mostly weak and some were not significant at the county scale. The study also revealed that topography, land use and climate were the main driving factors affecting the distribution of HESs and their relationships. This study suggested that the sub-catchment scale was more suitable for policy analysts and policy-makers that are concerned with HESs.

Field scale quantification indicates potential for variability in return flows from flood irrigation in the high altitude western US

The assessment of hydrologic ecosystem services associated with flood irrigation in the western United States is particularly limited by a lack of data about return flows. Return flows, the portion of applied water that returns to adjacent surface and groundwater hydrologic systems during flood irrigation, may provide wildlife habitat, recharge aquifers, and supplement late season baseflows. To improve understanding about variability in the timing and volume of return flows to improve management and policy decisions associated with different irrigation management techniques, our study used an agricultural water balance that combined hydrologic, geophysical, and meteorological tools. We directly measure key components of the water balance and quantify error and uncertainty on a ∼100 ha portion of the Bear Creek watershed in the Upper Wind River Basin of Wyoming. Over the course of a single irrigation season with average precipitation, we found that of the 1,133,000 m3 of water applied to irrigated lands, 328,000 m3 (29 % of applied water) returned to Bear Creek and 487,000 m3 (43 % of applied water) was consumptively used by vegetation. Our data also suggest that 59,000 m3 (18 % of total return flows) occurred more than two weeks after irrigation had ceased. The percent of return flow for this study site is slightly lower than the median of 43 % for all reviewed studies and the percent of delayed return flow—return flow after irrigation has ceased—is slightly higher than the median finding of 14 % across available studies. We found that return flows from flood irrigation at this site are lower than generalized regional estimates and those found by other studies. Thus, our study indicates that the amount and timing of return flows are not necessarily coupled (i.e. lower overall volume did not correspond to lowered late season contribution at this site). In addition, we found that these return flows support hydrologic ecosystem services including, riparian vegetation (wildlife habitat), groundwater storage, and late season baseflows.

Climate change in northern Patagonia: critical decrease in water resources

The current study presents an assessment of the impact of climate change on water yield, one of the main hydrological ecosystem services, in northern Patagonia. The outputs of regional climate models from the CORDEX Project for South America were used to drive the InVEST water yield model. CORDEX regional climate models project for the far future (2071–2100) an increase in temperature higher than 1.5 °C and a precipitation decrease ranging from − 10 to − 30% for the study area. The projected warmer and dryer climate emerges as a robust signal based on model agreement and on consistent physical drivers of these changes. Moreover, both the projected increase in evapotranspiration and the decrease in precipitation contribute to a strong decrease in water yield of around − 20 to − 40% in the headwaters of northern Patagonian watersheds. Comparison of the results in the two basins reveals that the land cover may be considered a buffer of water yield changes and highlights the key role of protected areas in reducing the vulnerability of water resources to climate change.

Comparison of the SWAT and InVEST models to determine hydrological ecosystem service spatial patterns, priorities and trade-offs in a complex basin

• We compared the applicability of InVEST and SWAT in Nansihu Lake basin. • Comparison included the spatial pattern, trade-offs and priorities of three HESs. • The two models provide same reference though some differences in specific values. • Model Users should consider three kinds of conditions and four important factors. Models for the assessment of ecosystem services are important tools for policy-makers and researchers. However, the simulation results of different models vary greatly, and it is difficult for policy-maker to select a suitable model for specific areas. As a result, we compared the results of three hydrological ecosystem services (HESs) in a basin with diverse topography, Nansihu Lake basin, China, including the water supply, soil conservation and water purification services estimated by the Soil and Water Assessment Tool (SWAT) and the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model. Further comparisons of the HES results were conducted in the application of spatial pattern, priority and trade-off analyses through spatial statistics, hot spot and correlation analyses. Firstly, the results showed that the HES values in whole basin simulated by SWAT model were a little higher than those in InVEST model. Secondly, the spatial patterns of soil conservation service simulated by the two models were approximately similar in whole basin because of proximate simulation algorithm and input data, but the spatial distribution of the other two HESs varied greatly. In particular, the spatial patterns of water supply service simulated by the two models were more similar in hill areas than those in plain areas, while the spatial patterns of water purification service displayed opposite result. Furthermore, the distributions of hot and cold spots of HESs simulated by the two models were approximately consistent. Thirdly, the results of relation analysis to HESs were similar to SWAT and InVEST model roughly. The study suggested that the results of the two models could provide similar frames of reference for management and policy-making although different simulation results between the two models. This research can provide the theoretical basis for model selection, policy decision-making and regional ecosystem management.

Identifying hotspots for investment in ecological infrastructure within the uMngeni catchment, South Africa

In recent times, there has been a growing recognition of the role which ecological infrastructure (EI) can play within the water resources management arena. However, practice has generally lagged conjecture regarding the integration of EI in the water resources management decision-making process. In this study, we aim to demonstrate how the state-of-the-art in ecosystem service modelling can be implemented to guide decision making with regards to investments in EI to improve the delivery of specific hydrological ecosystem services (HES) within the uMngeni catchment. For this purpose, the Resource Investment Optimization System (RIOS) and Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) models were applied to identify priority areas for investment and to evaluate the HES benefits that can potentially be achieved. Several global and local data sets were used to provide the requisite inputs to perform alternative land management scenario simulations. The results of these simulations demonstrated that potential investments in EI within the uMngeni catchment can lead to substantial reductions in sediment export (≈47%). Although, this may be accompanied by marginal decreases in the surface water yield (≈1.40%), there is a net benefit associated with reducing sediment export. Despite, these investigations being limited in their representation of HES due to inter alia the lack of localized data sets and inherent model limitations, the study successfully demonstrated how the RIOS and InVEST models can be collectively applied to guide decision-making regarding investments in EI.

Spatial conservation areas for water yield hydrological ecosystem services with their economic values effects under climate change: a case study of Teshio watershed located in northernmost of Japan

Abstract Water resources prioritization conservation planners are increasingly becoming aware of the economic value of water supply ecosystem services (ESs) under climate changes. Here we assessed how the water yield ES framework is implemented in the current spatial prioritization conservation of the water resources under climate change across the Teshio River watershed. We applied the systematic conservation model to optimize the area for water resources which satisfied the protection targets with and without considering economic values of the water yield provision service. The model indicated that the areas of spatial optimal ES protection for water yield with considering economic values were totally different from those without considering economic values of water resources. The optimal priority conservation areas were concentrated in southwestern, southeastern, and some northern areas of this watershed. These places could guarantee water resources sustainability from both environmental protection and socio-economic development standpoints. Moreover, the spatial priority conservation areas for water yield with economic value from hydro-power electricity production were traded off against the areas for water yield with economic values from resident water-use and irrigation for rice. Therefore, the systematic conservation planning of water yield with economic values under climate changes may provide a useful argument to promote the conservation of water resources.

The Brazilian Forest Code and riparian preservation areas: spatiotemporal analysis and implications for hydrological ecosystem services

The Brazilian Forest Code (BFC) requires the preservation and restoration of forests in riparian preservation areas (RPAs). The total area in RPAs and the impacts of changes in the BFC on RPA requirements are uncertain due to lack of clarity about how RPAs are defined in practice. We reconstruct the history of the RPA rule, use a recent cadastral database (CAR) of the state of Rondonia to quantify the area of RPA by stream size and to document the impact of the 2012 changes in RPA requirements, and review the literature on hydrological ecosystem services (HES) in light of RPA rules. We find that most (64%) of the area in RPAs in the state of Rondonia was illegally deforested by 2017, and the 2012 regulations require restoration of only half of that cleared area. Most of the RPA is located along small streams ( 200 m wide) was forested. Current restoration requirements (5 m regardless of stream width) for very small properties (< 60 ha) are likely inadequate to restore HES. Preservation of forest along large streams remains important, but policy and management should also emphasize the preservation and restoration of forest along small streams because they account for most of the riparian preservation area, with important implications for humans and ecosystems.

Spatial priority areas for individual and multiple hydrological ecosystem services with economic costs across teshio watershed, northernmost of Japan

Spatial priority areas for individual and multiple hydrological ecosystem services with economic costs across watershed through systematic conservation model represent a significant step toward cost-effective, transparent allocation of resources for ecosystem conservation and socio-economic development. However, current studies demonstrated that few economic costs derived from natural resources into hydrological ecosystem services reserve networks were involved into spatial conservation of hydrological ecosystem services. Therefore, there is a need for more challenging and integrated testing of economic costs to systematic conservation of hydrological ecosystem services across real-world watershed in order to build effective and reliable priority areas for hydrological ecosystem services. Here though systematic conservation model, we constructed spatial priority areas for multiple hydrological ecosystem services with different economic costs in Teshio watershed, northernmost of Japan. We demonstrated that economic costs impacted on the changes in spatial priority areas under a set of conservation targets and can obviously shift spatial patterns of priority areas for individual and multiple hydrological ecosystem services, which can increase the cost-effectiveness success of ecosystem service conservation for different stakeholders. Additionally, we examined how spatial correlations between priority areas for individual and multiple hydrological services under different economic cost scenarios, which can be recognized as surrogates to measure the ecosystem services tradeoffs from economic and ecological standpoint in the reserve networks designs. Therefore, integrating economic costs into ecosystem-based conservation in watershed is more-comprehensive ecological-economic conservation framework.

Soil Hydrothermal Characteristics among Three Typical Vegetation Types: An Eco-Hydrological Analysis in the Qilian Mountains, China

Soil moisture is a central theme in eco-hydrology. Topography, soil characteristics, and vegetation types are significant factors impacting soil moisture dynamics. However, water loss (evapotranspiration and leakage) and its factors of the self-organized vegetation pattern are not clear, which has significant ecologic functions and contributes to different hydrological ecosystem services. From an eco-hydrological point of view, we relied on the observation of rainfall, soil moisture, and soil temperature in the growing season of a drought year to compare soil moisture and temperature dynamics in terms of frequency/probability distribution and water loss among three typical vegetation types in the Qilian Mountains, China. The results indicated that shrubland (the semi-shaded slope) had the highest average soil moisture at the surface soil (0–40 cm) and soil profile during the growing season, while grassland (the south-facing slope) had the lowest daily average soil moisture and highest daily average soil temperature at the surface soil and soil profile. Spruce forest (the shaded slope) had the lowest daily average soil temperature at the surface soil and soil profile (p &lt; 0.001). Water loss among the three vegetation types has a clear positive relationship with soil water content and a negative relationship with soil temperature. The values of water loss between values of water loss at the wilting point and maximum evapotranspiration point tend to occur in wetter soil moisture under the spruce forest and shrubland, whereas that of grassland emerges in drier soil moisture. The spruce forest and shrubland experienced higher water loss than the grassland. Although the spruce forest and shrubland had a better capacity to retain soil water, they also consumed more soil water than the grassland. Soil moisture may be the main factor controlling the difference in water loss among the three vegetation types. These findings may contribute to improving our understanding of the relationship between the soil moisture dynamics and vegetation pattern, and may offer basic insights for ecosystem management for upstream water-controlled mountainous areas.

Functional diversity overrides community-weighted mean traits in linking land-use intensity to hydrological ecosystem services

Land-use intensification can importantly influence terrestrial ecosystem services by altering plant functional traits. Although we know that functional traits influence both ecosystem properties and services, we do not fully understand the mechanistic pathways governing these relationships nor how they will respond to global climate change. To identify the impact pathways of land-use intensity on hydrological services under changing precipitation regimes, we monitored hydrological services in 15 plots of different land-use types during 25 precipitation events (6 light, 8 moderate, and 11 heavy rains). Bayesian structural equation modeling was used to quantify the direct and indirect effects between land-use intensity, functional trait components (community weighted mean [CWM] and functional diversity [FD]), ecosystem properties (canopy density, litter fall and fine-root density), and hydrological services under different rainfall intensities. The impact of land-use intensity on hydrological service provisioning was regulated by plant functional traits regardless of intensity rainfall. Under light and moderate rain, FD significantly influenced hydrological services by altering canopy density and fine-root density, but we found no significant effect of CWMs. Under heavy rain, FD had significant, and greater, impacts on hydrological services than CWM of traits, although CWM of traits influenced hydrological services provision indirectly by altering canopy density and fine-root density. Land-use intensity indirectly affected hydrological services mainly by altering FD regardless of rainfall intensification, suggesting that the reduction of niche differentiation caused by land-use intensity is the main mechanism of hydrological services degradation. Our results suggested that the effect of land-use intensity on hydrological services are likely to change with increasing frequency of extreme precipitation events because of the different underlying mechanism at play and emphasize the importance of FD in maintaining hydrological services in respond to global environmental changes.

Combining Global Remote Sensing Products with Hydrological Modeling to Measure the Impact of Tropical Forest Loss on Water-Based Ecosystem Services

In the Lower Mekong River Basin (LMB), deforestation rates are some of the highest in the world as land is converted primarily into intensive agriculture and plantations. While this has been a key for the region’s economic development, rural populations dependent on the freshwater water resources that support their fishing and agriculture industries are increasingly vulnerable to the impacts of flood, drought and non-point source pollution. Impacts of deforestation on ecosystem services (ES) including hydrological ES that control the availability and quality of fresh water across the landscape, regulating floods and droughts, soil erosion and non-point source pollution are known. Despite this understanding at the hillslope level, few studies have been able to quantify the impact of wide-scale deforestation on larger tropical watersheds. This study introduces a new methodology to quantify the impact of deforestation on water-based ES in the LMB with a focus on Cambodia by combining spatial datasets on forest loss from remote sensing and spatially-explicit hydrological modeling. Numerous global and regional remote sensing products are synthesized to develop detailed land use change maps for 2001 to 2013 for the LMB, which are then used as inputs into a hydrological model to develop unique spatial datasets that map ES changes due to deforestation across the LMB. The results point to a clear correlation between forest loss and surface runoff, with a weaker but upward trending relationship between forest loss and sediment yield. This resulted in increased river discharge for 17 of the 22 watersheds, and increased sediment for all 22 watersheds. While there is considerable variability between watersheds, these results could be helpful for prioritizing interventions to decrease deforestation by highlighting which areas have experienced the greatest change in water-based ES provision. These results are also presented in a web-based platform called the Watershed Ecosystem Service Tool.

Assessing the implementation of Payments for Hydrological Ecosystem Services in Peru through a bottom‐up stakeholder analysis: Case study of Lima, Peru

AbstractPayments for Ecosystem Services (PES) represent a revolutionary conservation paradigm aimed at providing a sustainable financing for conservation, assuring the continued supply of ecosystem services (ES) for different beneficiaries while having the opportunity to improve sustainable livelihoods of rural communities providing these services. Whereas PES schemes are increasingly being developed all over the world, Peru has created a national legislative framework to operationalize them, called Rewarding Mechanisms for Ecosystem Services (MRSE), with an especial development on Hydrological Ecosystem Services (MRSEH) to sustain good quality and quantity of drinking potable water for urban areas. However, a lack of coordination, miscommunications, and unintegrated decision making process among the wide variety of stakeholders involved, especially urban (downstream water users) and rural stakeholders (ES upstream providers) has caused several challenges for the government to be implemented. This paper proposes an innovative methodology tool aimed to overcome these challenges, based on an in‐depth bottom‐up stakeholder analysis able to identify and understand those problems, and proposes sustainable win‐win upstream–downstream interventions to carry out in the future. A detailed review of the available literature on bottom‐up stakeholder participation methodology and a deep understanding of the MRSEH socio context were completed. We conclude that this methodology has the potential to be applied in any MRSEH of Peru at the design stage and also recommend that more research related with MRSEH stakeholder engagement should be conducted.

Climate Change Impact on Spatiotemporal Hotspots of Hydrologic Ecosystem Services: A Case Study of Chinan Catchment, Taiwan

Hydrologic ecosystem services are greatly affected by the changing climate. In this study, the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model was used to quantify hydrologic ecosystem services. Five general circulation models (GCMs) and two representative concentration pathways (RCPs) were selected to estimate hydrologic ecosystem services. The Local Indicators of Spatial Association (LISA) index was used to identify hydrologic ecosystem hotspots. The hotspots were used to evaluate the impact of climate change on the services. Results indicate that annual water yields vary from −17% to 8%, with significant intra-year fluctuation. Compared to baseline data, the CESM1-CAM5 predicts an increase of 45% in June, but HadGEM2-AO predicts a drop to only 12% in January. Sediment export results show a similar trend to water yield, with sediment export increasing significantly under RCP 8.5, and monthly sediment export increases concentrated from June and October. Nitrogen and phosphorous exports both show less significant changes but obvious intra-year variations. The CESM1-CAM5 predicts strong seasonal and spatial variation of the hydrologic ecosystem services. Our proposed approach successfully identifies annual and monthly hotspot spatial changes of hydrologic ecosystem services under climate change.

Impacts of Climate Change and Urban Expansion on Hydrologic Ecosystem Services in the Milwaukee River Basin

Land use/land cover (LULC) and climate changes could affect water quantity and quality and thus hydrologic ecosystem services (ES). However, studies of these impacts on hydrologic ES are limited by the current methods and techniques. We attempted to find out how the LULC and climate changes impact hydrologic ES at different temporal scales so that decision-makers can easily understand hydrologic ES variations for guiding management plans. In this study, we analyzed the impacts of LULC and climate changes on hydrologic ES in the Milwaukee River basin, USA with a conceptual modeling framework for hydrologic ES. The model framework was applied to a series of climate and urban expansion scenarios. Two hydrologic responses (streamflow and sediment) and three hydrologic ES (water provision index (WPI), flood regulation index (FRI), and sediment regulation index (SRI)) were calculated. Major findings include: (1) Climate change has much larger impacts than LULC at the monthly scale. For example, the impacts of climate change on streamflow were −6 to 9 m3/s whereas those of LULC change were −0.4 to 0.2 m3/s. Also, WPI (ranging from 0 to 1) changed between −0.16 and 0.07 with climate change but between −0.02 and −0.001 with LULC changes. (2) Compared to changes at the annual scale, the results show much larger variabilities as monthly time-series and mean monthly numbers. These findings suggest that the climate change weighs more than the realistic LULC change in term of impacts on hydrologic ES and those impacts can be identified with results at the monthly temporal scale. This approach with the framework and scenarios can better support management planning for decision-makers with detailed results and temporal precision.

Modelling Development of Riparian Ranchlands Using Ecosystem Services at the Aravaipa Watershed, SE Arizona

This paper describes how subdivision and development of rangelands within a remote and celebrated semi-arid watershed near the US–Mexico border might affect multiple ecohydrological services provided, such as recharge of the aquifer, water and sediment yield, water quality, flow rates and downstream cultural and natural resources. Specifically, we apply an uncalibrated watershed model and land-change forecasting scenario to consider the potential effects of converting rangelands to housing developments and document potential changes in hydrological ecosystem services. A new method to incorporate weather data in watershed modelling is introduced. Results of introducing residential development in this fragile arid environment portray changes in the water budget, including increases in surface-water runoff, water yield, and total sediment loading. Our findings also predict slight reductions in lateral soil water, a component of the water budget that is increasingly becoming recognized as critical to maintaining water availability in arid regions. We discuss how the proposed development on shrub/scrub rangelands could threaten to sever imperative ecohydrological interactions and impact multiple ecosystem services. This research highlights rangeland management issues important for the protection of open space, economic valuation of rangeland ecosystem services, conservation easements, and incentives to develop markets for these.