Fragments, functions and flows - the scaling of biodiversity and ecosystem services in urban ecosystems

城市面积仅占地球陆地面积的2.8%，但超过50%的人口生活在其中，而且这一比例正在迅速增长。人口的高度集中产生了各种各样的重要后果。这些与环境的关系最近引起了媒体、压力集团、决策者、研究人员以及地方和国家政府的极大关注。特别令人关切的是，如何才能最有效地改善城市地区的环境状况，提高城市居民与自然环境之间的相互作用水平，以及提高城市地区对更广泛地提供生态系统服务的贡献。这就提出了一个关键问题，即城市地区生物多样性和生态系统服务之间的关系形式，城市地区的结构如何（不同类型和程度的不透水面和透水面的空间结构;城市形态）影响这些关系，因此，如何最好地管理现有结构，以及如何规划未来结构以达到最佳效果。尽管对层次和分布的理解近年来，城市地区的生物多样性和生态系统服务都有了显著改善，但对城市地区生物多样性和生态系统服务之间的关系的研究却非常少（而且在主要的经验研究汇编中基本上没有）。事实上，这些环境构成了重大和不寻常的挑战：-城市景观高度分散，大部分被建筑物和路面封闭;-绿地嵌入建筑物和道路的复杂马赛克中，对整个城市景观中生物多样性和生态系统服务的流动施加了重大限制和方向性;- 人类对这些环境的管理强度可能导致能源流动的空间格局和规模，生态系统服务所依赖的不会自然产生的物质和生物多样性;以及，-城市地区的人口聚集通常需要不太传统的方法来进行生态研究，为了确定这些生物多样性-生态系统服务关系，加深理解并检验这种理解，我们对该项目的总体方法包括五个主要步骤。我们将：-确定城市地区的空间生态结构;-确定生物多样性-生态系统服务关系以及连通性对它们的影响;-确定生物多样性的流动以及在选定情况下的服务提供;-通过实验扰动这些流动，以确定对生态系统服务提供的影响;并-将这些研究结果以空间上明确的模型的形式整合起来，这些模型将构成“生态系统服务”的基础。GIS模型层。这将使我们能够加深理解，并为利益相关者（例如规划者、当地人民和非政府组织）提供如何测试不同开发提案的“场景”的说明，为基于合理科学和利益相关者参与的决策提供支持。

Urban areas cover just 2.8% of the Earth's land area, but over 50% of the human population lives in them, and these proportions are growing rapidly. Such heavy concentration of people has a wide variety of important consequences. Those for their relations with the environment have attracted much recent attention from the media, pressure groups, policy makers, researchers, and local and national government. Of particular concern have been how improvements can most effectively be made to the environmental conditions experienced in urban areas, to the levels of interaction between urban dwellers and the natural environment, and to the contribution of urban areas to the broader scale provision of ecosystem services. This raises the key issue of the form of relationships between biodiversity and ecosystem services in urban areas, how the structure of urban areas (the spatial structure of the different kinds and extents of impermeable and permeable surfaces; urban form) influences these relationships, and thus how the existing structure can best be managed and how future structure can be planned to best effect.Although understanding of the levels and distributions both of biodiversity and of ecosystem services in urban areas has improved dramatically in recent years the relationships between biodiversity and ecosystem services have been extremely poorly studied in urban areas (and are largely absent from major collations of empirical studies). Indeed, these environments pose significant and unusual challenges:- the urban landscape is highly fragmented, with large portions sealed by buildings and paving;- greenspaces are embedded in a complex mosaic of buildings and roads that imposes major constraints and directionality on the flows of biodiversity and ecosystem service delivery across the urban landscape;- the intensity of human management of these environments can give rise to spatial patterns and scales of flows of energy, materials and biodiversity on which ecosystem services depend that would not naturally occur; and,- the very aggregations of people that give rise to urban areas typically necessitate less conventional approaches to conducting ecological research therein, involving greater engagement with the general public, and less dependence on the use of large pieces of equipment, which is "out of bounds" to the general population.In order to determine these biodiversity-ecosystem service relationships, develop deeper understanding and to test this understanding our overall approach to this project involves five main steps. We shall:- characterise the spatial ecological structure of urban areas;- determine biodiversity-ecosystem service relationships and the influence of connectivity on them;- determine the flows of biodiversity, and service delivery in selected cases;- experimentally perturb those flows to determine the impact on ecosystem service delivery; and- integrate these findings in the form of spatially explicit models which will form the basis of an "ecosystem service" layer for GIS models.This will enable us to deepen understanding, and to provide illustrations for stakeholders (such as planners, local people and NGOs) as to how "scenarios" of different development proposals might be tested, to provide support for decisions based on sound science and stakeholder engagement.