农业景观生物多样性功能和保护对策

研究表明,农业集约化生产和农业景观均质化导致农业景观生物多样性降低,致使生物多样性相关野生资源保护、自然授粉、害虫调节、水土涵养等生态系统服务功能受损,进而影响了农业可持续发展。本文对国内外农业景观生物多样性及其生态系统服务功能研究和实践进行了综述。分别探讨了农业景观在生物多样性保护、授粉服务、调节服务、水土涵养等多方面生态服务功能中发挥的作用及其生物多样性保护的意义,总结了欧美在农业景观生物多样性保护所采取的实践措施,指出中国虽然在生物多样性保护方面做出很多努力,但却忽略了对农业景观的保护,近些年的城市化和集约化发展都进一步加剧了农业景观生物多样性的丧失,亟需借鉴欧美国家经验提出我国的农业景观生物多样性保护策略。我们认为保护和提高农业景观生物多样性的生态集约化对维护农作物产量,改善品种具有重要的作用。农业景观生物多样性保护需要从农田生态系统和农业景观两个尺度上开展农业景观综合管理,提高农田作物和景观植物多样性和异质性,恢复和提高生物多样性及其生态服务功能。最后,针对我国农业可持续发展面临的问题和需求,建议从政策和法规、监测和评估、工程技术研发、技术集成示范、生态补贴制度、培训和推广等方面,开展农业景观生物多样性保护。     

Do we protect biological originality in protected areas? A new index and an application to the Bonifacio Strait Natural Reserve

Changes in biodiversity may disrupt the ecological functions performed by species assemblages. Hence, we urgently need to examine the implications of biodiversity loss not only in terms of species conservation but also in terms of sustainability of ecosystem services. The ability of protected areas to maintain local species richness has been clearly demonstrated. However, preserving goods and services provided by ecosystems requires not only the conservation of species richness but also the conservation of the most ‘original’ species, i.e. the ones with the highest average rarity of their attributes which are likely to perform some unique functions in ecosystems. We proposed a new conservation of biological originality (CBO) index as well as associated randomization tests to quantify the ability of protected areas to maintain viable populations for the most original species. As an application, we used long-term fisheries data collected in the Bonifacio Strait Natural Reserve (BSNR) to determine the species which benefited from the protection reinforcement in 1999. We also estimated a set of 14 ecomorphological functional traits on the 37 fish species caught in the BSNR and we obtained a functional originality value for each species. As a result, we found that functional originality was significantly protected in the fish assemblage of the BSNR: species with the most original functional trait combinations became more abundant after 1999. Our finding suggests that protecting most original species is an insurance against functional diversity erosion in the BSNR. More generally, our new index can be used to test whether protected areas may protect preferentially the most original species and whether restorative management promotes the reestablishment of the most original species with particular habitat requirements.     

Biodiversity conservation in human-modified landscapes of Mesoamerica: Past, present and future

Mesoamerica provides a unique context for biodiversity conservation in managed landscapes because of its geography, history of human intervention, and present conservation and development initiatives. The long and narrow form of the Mesoamerican landmass, and its division by a central mountain range, has served as both a bridge and a barrier. Conservation efforts in Mesoamerica are unique for the emphasis they place on regional connectivity through the Mesoamerican Biological Corridor and on biodiversity conservation in managed landscapes. The emphasis on conservation in agricultural systems has fostered innovations in payment for ecosystem services, and provides novel insights on the functional role that biodiversity plays in the provisioning of ecosystem services. The increasing rate of economic development in the region and the advent of new payment for ecosystem service schemes have provided new opportunities for forest regeneration and restoration. However, the small scale of private landholdings and the diversity of land uses featured in the region, while contributing to biodiversity conservation due to their structural and floristic complexity, present challenges for biodiversity monitoring and management.     

基于生物多样性和生态系统服务的生态农场景观设计

近年来随着民众对良好生态环境和优质食品需求的增加,生态农场在我国蓬勃兴起。如何设计和建造生态农场成为新的研究领域。其中将生物多样性和生态系统服务整合到生态农场设计被认为是保障生态农场可持续生产的关键。本研究在回顾生态农场发展历程,分析生态农场中生物多样性的内涵,总结生态农场的景观结构、生物多样性和生态系统服务的关系及其应用的基础上,提出了以提升和利用生物多样性和生态系统服务为目标的生态农场景观结构优化的设计原则。研究建议生态农场的景观设计应主要包括农场与周围景观的关系、种植系统设计和有益生物栖息地的保护和重建3方面的内容,并具体提出了每个方面需遵循的一般设计原则。同时,研究以我国南方水稻主产区新建水稻生态农场设计为例,印证了上述原则和方法在实践中的可行性。研究表明,为了更好地将生物多样性整合到生态农场建设中,未来需要深入认识生物多样性及其生态功能,认识生物多样性与农业产量和收益的关系,开发利用能够促进有益生物多样性和生态系统服务的功能植物,并推动生态农场实施生物多样性保护的生态补偿政策的制定。本研究对推动将生物多样性保护和生态服务管理整合到生态农场设计提供了方法指导和实证,对生态农场的发展建设具有参考借鉴意义。     

Prospects for biodiversity conservation in the Atlantic Forest: Lessons from aging human-modified landscapes

Recent global assessments have shown the limited coverage of protected areas across tropical biotas, fuelling a growing interest in the potential conservation services provided by anthropogenic landscapes. Here we examine the geographic distribution of biological diversity in the Atlantic Forest of South America, synthesize the most conspicuous forest biodiversity responses to human disturbances, propose further conservation initiatives for this biota, and offer a range of general insights into the prospects of forest species persistence in human-modified tropical forest landscapes worldwide. At the biome scale, the most extensive pre-Columbian habitats across the Atlantic Forest ranged across elevations below 800 masl, which still concentrate most areas within the major centers of species endemism. Unfortunately, up to 88% of the original forest habitat has been lost, mainly across these low to intermediate elevations, whereas protected areas are clearly skewed towards high elevations above 1200 masl. At the landscape scale, most remaining Atlantic Forest cover is embedded within dynamic agro-mosaics including elements such as small forest fragments, early-to-late secondary forest patches and exotic tree monocultures. In this sort of aging or long-term modified landscapes, habitat fragmentation appears to effectively drive edge-dominated portions of forest fragments towards an early-successional system, greatly limiting the long-term persistence of forest-obligate and forest-dependent species. However, the extent to which forest habitats approach early-successional systems, thereby threatening the bulk of the Atlantic Forest biodiversity, depends on both past and present landscape configuration. Many elements of human-modified landscapes (e.g. patches of early-secondary forests and tree monocultures) may offer excellent conservation opportunities, but they cannot replace the conservation value of protected areas and hitherto unprotected large patches of old-growth forests. Finally, the biodiversity conservation services provided by anthropogenic landscapes across Atlantic Forest and other tropical forest regions can be significantly augmented by coupling biodiversity corridor initiatives with biota-scale attempts to plug existing gaps in the representativeness of protected areas.     

Sustaining biodiversity conservation in human-modified landscapes in the Western Ghats: Remnant forests matter

Human-modified tropical landscapes under semi-natural or agro-ecosystems often harbor biodiversity of significant conservation value. In the Western Ghats of India, these ecosystems also provide connectivity between protected areas and other remnant forests. We investigated the conservation value of these landscapes and agro-ecosystems using results from 35 studies covering 14 taxonomic groups. Large, conspicuous taxonomic groups and tree-covered land-use types have received much focus in this area of research in the Western Ghats. We computed a response ratio defined as the log ratio of species richness in human land use to species richness in forest control site from 17 studies. In a meta-analysis, we investigated variation of this ratio across studies with respect to three variables: taxonomic group, the land-use type sampled and the extent of forest cover within the study landscape. Higher forest cover within the landscape emerged as a major positive influence on biodiversity in human-modified landscapes for vertebrates and vegetation while no patterns emerged for invertebrates. Our results suggest that loss of remnant forest patches from these landscapes is likely to reduce biodiversity within agro-ecosystems and exacerbate overall biodiversity loss across the Western Ghats. Conservation of these remnant forest patches through protection and restoration of habitat and connectivity to larger forest patches needs to be prioritized. In the densely populated Western Ghats, this can only be achieved by building partnerships with local land owners and stakeholders through innovative land-use policy and incentive schemes for conservation.     

Forest restitution and protected area effectiveness in post-socialist Romania

The effectiveness of protected areas can diminish during times of pronounced socio-economic and institutional change. Our goals were to assess the effectiveness of Romanian protected areas at stemming unsanctioned logging, and to assess post-socialist logging in their surrounding landscapes, during a time of massive socio-economic and institutional change. Our results suggest that forest cover remained fairly stable shortly before and after 1990, but forest disturbance rates increased sharply in two waves after 1995 and 2005. We found substantial disturbances inside protected areas, even within core reserve areas. Moreover, disturbances in the matrix surrounding protected areas were even lower than inside protected area boundaries. We suggest that these rates are largely the result of high logging rates, triggered by rapid ownership and institutional changes. These trends compromise the goals of Romania’s protected area network, lead to an increasing loss of forest habitat, and more isolated and more fragmented protected areas. The effectiveness of Romania’s protected area network in terms of its ability to safeguard biodiversity is therefore most likely decreasing.     

Agricultural intensification and loss of matrix habitat over 23 years in the West Wimmera, south-eastern Australia

The global trend toward more intensive forms of agriculture is changing the nature of matrix habitat in agricultural areas. Removal of components of matrix habitat can affect native biota at the paddock and the landscape scale, particularly where intensification occurs over large areas. We identify the loss of paddock trees due to the proliferation of centre pivot irrigation in dryland farming areas as a potentially serious threat to the remnant biota of these areas. We used a region of south-eastern Australia as a case study to quantify land use change from grazing and dryland cropping to centre pivot irrigation over a 23-year period. We also estimated rates of paddock tree loss in 5 representative landscapes within the region over the same period. The total area affected by centre pivots increased from 0 ha in 1980 to nearly 9000 ha by 2005. Pivots were more likely to be established in areas which had originally been plains savannah and woodlands containing buloke (Allocasuarina luehmannii), a food source for an endangered bird. On average, 42% of paddock buloke trees present in 1982 were lost by 2005. In the two landscapes containing several centre pivots, the loss was 54% and 70%. This accelerated loss of important components of matrix habitat is likely to result in species declines and local extinctions. We recommend that measures to alleviate the likely negative impacts of matrix habitat loss on native biota be considered as part of regional planning strategies.     

Continental‐scale Impacts of Livestock Grazing on Ecosystem Supporting and Regulating Services

Grazing by livestock supports millions of people worldwide, particularly in drylands, but has marked negative effects on ecosystem services and functions. In Australia, its effects on ecosystem services have not been fully quantified. We examined the extent to which grazing by livestock influenced supporting (productivity, habitat for organisms and biodiversity) and regulating (carbon cycling and hydrological function) services, using data from published and unpublished studies on livestock grazing from a large number of sites across Australia. Grazing reduced our measure of supporting services by about 20% and regulatory services by 8%. On average, grazing reduced plant productivity by 40%, habitat value by 20%, and biodiversity, hydrological function and carbon sequestration by about 10%. Habitat and productivity showed strong declines with increasing grazing intensity, and carbon showed strong declines at the lowest and highest contrasts. Hydrological function and biodiversity did not decline with increasing grazing intensity. Overall, the results indicate that livestock grazing leads to substantial degradation at a continental scale by reducing ecosystem services associated with habitat provision, biodiversity, and soil and water functions. Management of livestock grazing will be critical if we are to retain functional levels of ecosystem services into the next century. Copyright © 2016 John Wiley & Sons, Ltd.