Biodiversity in the context of ecosystem services: the applied need for systems approaches

Recent evidence strongly suggests that biodiversity loss and ecosystem degradation continue. How might a systems approach to ecology help us better understand and address these issues? Systems approaches play a very limited role in the science that underpins traditional biodiversity conservation, but could provide important insights into mechanisms that affect population growth. This potential is illustrated using data from a critically endangered bird population. Although species-specific insights have practical value, the main applied challenge for a systems approach is to help improve our understanding of the role of biodiversity in the context of ecosystem services (ES) and the associated values and benefits people derive from these services. This has profound implications for the way we conceptualize and address ecological problems. Instead of focusing directly on biodiversity, the important response variables become measures of values and benefits, ES or ecosystem processes. We then need to understand the sensitivity of these variables to biodiversity change relative to other abiotic or anthropogenic factors, which includes exploring the role of variability at different levels of biological organization. These issues are discussed using the recent UK National Ecosystems Assessment as a framework.     

Valuing mangrove ecosystem services: linking nutrient retention function of mangrove forests to enhanced agroecosystem production

Mangroves are highly productive wetland ecosystems strategically located at the interface between land and sea. They play an important role in the biogeochemical cycles of the coastal environment, acting as sources of nutrients to adjacent marine and terrestrial ecosystems through active and passive transport. We examined the nutrient contents in mangrove and nonmangrove soils in and around the Bhitarkanika National Park, India and assessed whether the local agricultural producers were aware of and placed a value on this contribution of mangrove forests in enhancing agroecosystem productivity. Soil samples from both mangrove and nonmangrove areas were analysed and quantity of organic carbon, total nitrogen, available phosphorus and potassium were derived. The replacement cost method was used to derive the value of nutrients in mangrove soils. We estimated that each hectare of mangrove contains additional nutrients worth US$232.49 in comparison to nonmangrove areas. The difference in nutrient content in mangrove versus nonmangrove areas gave the value of US$3.37 million for the nutrients in 145 km² of mangrove forests. The agricultural producers were aware that mangrove forests act as a source of nutrients and were willing to pay a higher price for the land adjoining mangrove forests. Around 92% of the producers ranked nutrient retention as a secondary function of mangrove forests. Despite crop depredation from wild ungulates and conflict with salt water crocodiles the agriculturist finds the benefit to cost ratio of mangrove forests high and more than 76% were in favour of mangrove restoration. This study provides an opportunity to highlight the importance of mangrove ecosystems to the livelihoods of the local people and the urgent need to sustain these through proper policy and market interventions.     

人工鱼礁构建对海洋生态系统服务价值的影响——以深圳杨梅坑人工鱼礁区为例

基于深圳杨梅坑人工鱼礁区2008年的研究和统计数据,采用生态系统服务价值方法,系统分析了杨梅坑人工鱼礁建设对海洋生态系统的影响.结果表明:与深圳附近海域相比,杨梅坑人工鱼礁构建后旅游娱乐服务价值所占比例由87%降至42%,食品供给服务价值所占比例由7%升至27%,原材料供给、气候调节、空气质量调节、水质净化调节、有害生物和疾病的生物调节与控制、知识扩展服务价值所占比例少许提高;2008年,深圳杨梅坑人工鱼礁区单位面积服务价值为1714.7万元.km-2,远高于深圳市近海海洋生态系统的平均值和全球近海生态系统的平均值.人工鱼礁生态系统影响并改变了区域海洋生态系统服务价值结构,提高了区域生态系统服务价值,对于合理开发与利用海洋资源、修复受损的海洋生态环境和渔业资源有着重要意义.利用生态系统服务价值方法对人工鱼礁构建区进行评价,可以更好地反映人工鱼礁构建效益,能有效促进我国人工鱼礁建设的发展、提高海洋生态系统管理水平.