Adaptation of land management in the Mediterranean under scenarios of irrigation water use and availability

Meeting the growing demand for food in the future will require adaptation of water and land management to future conditions. We studied the extent of different adaptation options to future global change in the Mediterranean region, under scenarios of water use and availability. We focused on the most significant adaptation options for semiarid regions: implementing irrigation, changes to cropland intensity, and diversification of cropland activities. We used Conversion of Land Use on Mondial Scale (CLUMondo), a global land system model, to simulate future change to land use and land cover, and land management. To take into account future global change, we followed global outlooks for future population and climate change, and crop and livestock demand. The results indicate that the level of irrigation efficiency improvement is an important determinant of potential changes in the intensity of rain-fed land systems. No or low irrigation efficiency improvements lead to a reduction in irrigated areas, accompanied with intensification and expansion of rain-fed cropping systems. When reducing water withdrawal, total crop production in intensive rain-fed systems would need to increase significantly: by 130% without improving the irrigation efficiency in irrigated systems and by 53% under conditions of the highest possible efficiency improvement. In all scenarios, traditional Mediterranean multifunctional land systems continue to play a significant role in food production, especially in hosting livestock. Our results indicate that significant improvements to irrigation efficiency with simultaneous increase in cropland productivity are needed to satisfy future demands for food in the region. The approach can be transferred to other similar regions with strong resource limitations in terms of land and water.     

围填海造成的海岸带生态系统服务损耗的货币化评估技术探讨

从围填海负面生态影响的货币化评估的必要性和重要性入手,基于国内外相关研究的分析,将海岸带生态系统服务划分为两大类,一类是提供物质性产品和条件的供给服务;另一类是提供其他非物质性的服务,包括调节、文化和支持服务,并对供给、调节、文化和支持四类服务各自包含的具体子服务加以识别.在此基础上,针对海岸带生态系统提供的各类服务自身的特点,运用直接市场法、替代市场法、调查评价法和成果参照法,提出了围填海造成的海岸带生态系统服务损害的货币化评估技术选择的基本框架,并构建了四类服务(子服务)损耗货币化的相应评估模型.     

Groundwater dependent ecosystems. Part II. Ecosystem services and management in Europe under risk of climate change and land use intensification

Groundwater in sufficient amounts and of suitable quality is essential for potable water supplies, crop irrigation and healthy habitats for plant and animal biocenoses. The groundwater resource is currently under severe pressure from land use and pollution and there is evidence of dramatic changes in aquifer resources in Europe and elsewhere, despite numerous policy measures on sustainable use and protection of groundwater. Little is known about how such changes affect groundwater dependent ecosystems (GDEs), which include various aquatic and terrestrial ecosystems above ground and inside the aquifer. Future management must take this uncertainty into account. This paper focuses on multiple aspects of groundwater science, policy and sustainable management. Examples of current management methods and practices are presented for selected aquifers in Europe and an assessment is made of the effectiveness of existing policies such as the European Water Framework Directive and the Habitat Directive in practice and of how groundwaters and GDEs are managed in various conditions. The paper highlights a number of issues that should be considered in an integrated and holistic approach to future management of groundwater and its dependent ecosystems.     

Assessing the high impacts of land use change: spatial characteristics of land uses and ecological compensation based on payment for ecosystem services model in a mountainous area,China

Most impacts on ecosystem services (ESs) are related to land use changes that may cause ecosystem fragmentation and loss of ecosystem functions. Spatial planning focused on sustainable landscape development should consider the local potential for providing ESs as well as ecological conservation due to land use changes. To better address the issues that are related to ecological and the ecological and environmental conservation, ecological compensation could coordinate the development of the energy, the economy, and the environment by internalizing environmental externalities and adjusting for the relationships with stakeholders’ benefits. In this study, we developed a framework for analyzing the spatial characteristics of land uses and calculating ecological compensation based on pay for ecosystem services (PESs) from 1995 to 2010 in the upstream of Min River, China. In terms of lacunarity analysis, we firstly explored the spatial patterns of land uses in these two periods that occurred at different spatial characteristic scales. We also observed a strong relationship between lacunarity values and the different distribution patterns of land uses. We then investigated changes in ESs in response to land use change through the assignment of per unit area ecological service value (ESV) method. The total value of ESs dropped from 449.97 billion yuan in 1995 to 441.35 billion yuan in 2010, exhibiting decreasing rate, mainly due to the degradation of woodlands. Soil formation and retention, gas regulation, and biodiversity protection were the three largest ESs, contributing about 50% of the total ESV. Considering the changed relation between social and economic indicators and ESV based on spatial visualization and analysis, we finally constructed a quantitative estimate model for ecological compensation taking a village as study unit and determined standard value so as to evaluate ecological compensation from 1995 to 2010. Spatial differences of the ecological compensation were significant among all the villages and towns. The maximum ecological compensation account (ranged from 1.68 to 8.54 billion yuan) appeared in the villages approximated to Li County, Heishui County, and Songpan County, Sichuan, People’s Republic of China. This proposed framework provides a better understanding of spatial characteristic scales of land uses and enables evaluation of the ecological integrity of landscapes. It also fills up the gap in the field of quantitative evaluation of regional ecological compensation and provides a feasible way to reconcile the conflicts among benefits in the economic, social, and ecological sectors.

     

Relationships between diversity of grassland vegetation, field characteristics and land use management practices assessed at the farm level

In order to assess the impact of policies to encourage extensification in less favoured areas and improve our knowledge of extensive livestock systems, we analyzed relationships between the diversity of grassland vegetation and land use management practices and field characteristics. This study, conducted on a mountainous area in the centre of France, was based on 149 fields, mainly of natural grasslands belonging to 7 farmers. Regression analyses were performed to analyze the relations between the grassland vegetation types (five types established from the list of dominant species), management practices (cutting versus grazing and fertilization) and the topographic (altitude and aspect) and topologic (slope, distance and surface area) characteristics of the fields. The land use management rules used by the farmers were studied by specifying the grazing management rules of the herd (dairy cows), as well as those for conserved forage (mainly hay or silage) and were identified from observations mentioned on the “grazing schedules”, as well as from interviews at the beginning, in the middle and at the end of the study period. The statistical analysis showed that neither the topographic characteristics of the fields nor the distance from the cowshed or surface area were correlated with the grassland vegetation types. It was the management practices used, largely determined by the field slope, which determined the grassland vegetation type. On the other hand, farmers’ statements showed that the grazing and cutting management rules were mostly determined by the slope of the fields and the distance from the cowshed and, to a lesser extent, by the altitude and aspect. These results showed that the farmers take into consideration environmental differences when choosing fields to allocate for grazing and cutting at different seasons, particularly when they are constrained by these features. Nevertheless, when the constraints were minimal, a wide diversity of grassland vegetation types was also observed. This diversity was a result of attributing different functions to the fields which led to different management practices (defoliation methods and fertilization) and, thus, to different grassland vegetation types. Consequently, for farms where animal feed requirements vary according to the time of the year and the type of animal, we suggest that diversity in the grassland vegetation types is a sound component of these livestock systems.     

Carbon sequestration capacity and productivity responses of Mediterranean olive groves under future climates and management options

The need to reduce the expected impact of climate change, finding sustainable ways to maintain or increase the carbon (C) sequestration capacity and productivity of agricultural systems, is one of the most important challenges of the twenty-first century. Olive (Olea europaea L.) groves can play a fundamental role due to their potential to sequester C in soil and woody compartments, associated with widespread cultivation in the Mediterranean basin. The implementation of field experiments to assess olive grove responses under different conditions, complemented by simulation models, can be a powerful approach to explore future land-atmosphere C feedbacks. The DayCent biogeochemical model was calibrated and validated against observed net ecosystem exchange, net primary productivity, aboveground biomass, leaf area index, and yield in two Italian olive groves. In addition, potential changes in C-sequestration capacity and productivity were assessed under two types of management (extensive and intensive), 35 climate change scenarios (ΔT-temperature from +?0 °C to +?3 °C; ΔP-precipitation from 0.0 to ??20%), and six areas across the Mediterranean basin (Brindisi, Coimbra, Crete, Cordoba, Florence, and Montpellier). The results indicated that (i) the DayCent model, properly calibrated, can be used to quantify olive grove daily net ecosystem exchange and net primary production dynamics; (ii) a decrease in net ecosystem exchange and net primary production is predicted under both types of management by approaching the most extreme climate conditions (ΔT?=?+?3 °C; ΔP?=???20%), especially in dry and warm areas; (iii) irrigation can compensate for net ecosystem exchange and net primary production losses in almost all areas, while ecophysiological air temperature thresholds determine the magnitude and sign of C-uptake; (iv) future warming is expected to modify the seasonal net ecosystem exchange and net primary production pattern, with higher photosynthetic activity in winter and a prolonged period of photosynthesis inhibition during summer compared to the baseline; (v) a substantial decrease in mitigation capacity and productivity of extensively managed olive groves is expected to accelerate between +?1.5 and +?2 °C warming compared to the current period, across all Mediterranean areas; (vi) adaptation measures aimed at increasing soil water content or evapotranspiration reduction should be considered the mostly suitable for limiting the decrease of both production and mitigation capacity in the next decades.

     

Simulated dynamics of carbon stocks driven by changes in land use, management and climate in a tropical moist ecosystem of Ghana

Sub-Saharan Africa is large and diverse with regions of food insecurity and high vulnerability to climate change. This project quantifies carbon stocks and fluxes in the humid forest zone of Ghana, as a part of an assessment in West Africa. The General Ensemble biogeochemical Modeling System (GEMS) was used to simulate the responses of natural and managed systems to projected scenarios of changes in climate, land use and cover, and nitrogen fertilization in the Assin district of Ghana. Model inputs included historical land use and cover data, historical climate records and projected climate changes, and national management inventories. Our results show that deforestation for crop production led to a loss of soil organic carbon (SOC) by 33% from 1900 to 2000. The results also show that the trend of carbon emissions from cropland in the 20th century will continue through the 21st century and will be increased under the projected warming and drying scenarios. Nitrogen (N) fertilization in agricultural systems could offset SOC loss by 6% with 30 kg N ha⁻¹ year⁻¹ and by 11% with 60 kg N ha⁻¹ year⁻¹. To increase N fertilizer input would be one of the vital adaptive measures to ensure food security and maintain agricultural sustainability through the 21st century.