An Emergy-Based Approach to Assess and Valuate Ecosystem Services of Tropical Wetland Pastures in Brazil

Wetland grasslands are important ecosystems for raising beef cattle, because they are highly productive and present forages with high quality. Most of these ecosystems are threatened by overgrazing or by being replaced by exotic pastures. Emergy synthesis approach was used to assess and value the services provided by native pastures wetland under three conservation status and also to compare them to exotic pastures on wetlands. The ecosystem service that was assessed included forage provision for calves production estimated from grazing capacity of cow with calf at the foot. Habitat maintenance to plant diversity and wild herbivores were also evaluated. The results showed that natural wetland pastures with better conservation status provided valuable ecosystem services and are highly renewable. Data envelopment analysis (DEA) showed that regardless of the conservation state of the natural pastures, wet native grasslands were more efficient than wet exotic grasslands. Replacing native pastures by exotic ones may reduce plant diversity and the renewability of the system. The proposed method has a holistic approach to pasture ecosystems and is able to help decision-makers to define sustainable management practices and to subsidise public policies when it comes to payments regarding ecosystem services.

Rating the Degradation of Natural Hay Pastures in Northern China

Natural hay pastures in semi-arid pastoral areas produce the highest yields of hay in northern China.However, long-term continuous hay harvesting with no rest interval has resulted in severe degradation across widespread areas of these natural hay pastures. In addition, no clear data exist on the spatial distribution or degree of degradation occurring in natural hay pastures primarily because a nationally unified and normative evaluation standard is lacking. In view of the above problems, we employed an analytic hierarchy process to carry out screening and accuracy validation of evaluation indicators for natural hay pastures in north China grasslands(temperate meadow steppes, temperate steppes, mountain meadows, and lowland meadows). Our study identified seven easily measured indicators that reflect the state of natural hay pastures(average height, aboveground biomass, coverage, proportion of medium grasses, litter biomass, proportion of degradation-indicative plants, and proportion of bare spots and saline-alkali spots). A five-level scoring method was employed to delineate the threshold range for these indicators, The results of this study show that this method effectively solved the technical bottleneck for graded evaluation of degradation in natural hay pastures. This provides a theoretical basis for the scientific assessment of natural hay pasture degradation as well as important technical support for sustainable use of natural hay pastures and livestock production.