Predicting the scale of landscape context effects: How big is a landscape?

背景技术背景：可以说，在保护中最重要的空间尺度问题是确定景观背景影响特定人口或社区的距离。我们知道，没有池塘、森林或保护区是一个岛屿。生态变量，如人口丰富度或物种丰富度的强烈影响的景观背景下，例如周围的道路密度，森林覆盖，或城市化。为了采取有效的保护行动，我们需要知道这些影响发生的距离，即景观的“影响范围”。预测影响尺度也是景观生态学研究的关键。如果在错误的程度上测量景观变量，景观背景的影响可能无法检测到，和/或景观效应的相对重要性将被错误地估计。然而，许多研究人员任意选择一个单一的空间尺度进行分析，其他人则根据生物体的运动生物学来缩放景观，合理的假设是，效应的尺度取决于生物体与其环境相互作用的空间范围。到目前为止，对这一假设的检验结果好坏参半，表明还有其他因素在起作用。例如，人口统计参数（例如，繁殖率），一个物种的运动行为的细节，和物种的相互作用？尺度如何变化，取决于景观预测（道路密度，森林覆盖等）？它是否取决于测量的响应，例如，丰度，物种丰富度？目前还没有全面的理论来预测景观背景对人口和社区反应的影响规模。目的：在接下来的5年里，我的目标是建立和验证一套假设，用于预测景观背景对人口和社区反应的影响规模。方法：我提出了八个假设，提出的影响规模和（一）物种特征（扩散，繁殖率，资源利用，天敌的特征），（二）响应变量（丰度，发生，物种丰富度），（三）景观变量的类型（通过资源的可用性，如栖息地数量，或通过死亡率，如道路密度）之间的关系。我们将使用基于个人的空间模拟模型来评估假设，并估计影响效应规模的因素的相对重要性。然后，我们将首先（i）使用多尺度实证研究估计景观预测因子对多个个体物种和群落响应的影响尺度，然后（ii）进行跨物种（或物种组）比较，以测试观察到的影响尺度是否如假设和模拟预测的那样变化。由于我的目标是开发一个通用的，有效的理论来预测效果的规模，我们将进行几个不同的物种组的实证测试，包括：森林小型哺乳动物，池塘和森林栖息的两栖动物，树皮和木材钻孔甲虫，森林地面植物，和alvar植物。重要性：我们知道，选择“正确的”空间尺度在景观和保护生态学中非常重要，但我们通常“即兴发挥”，因为我们事先不知道正确的尺度。拟议的研究将建立有效的理论，使景观和保护生态学家选择正确的空间尺度进行分析和应用。这将（i）增加景观生态学研究的推理能力，（ii）大大提高大规模保护行动的有效性，确保它们在正确的空间范围内实施，以实现保护目标。

BACKGROUND: Arguably the most important spatial scaling problem in conservation is identification of the distance within which the landscape context affects a given population or community. We know that no pond, forest patch, or protected area is an island. Ecological variables such as population abundance or species richness are strongly influenced by the landscape context, e.g. the surrounding road density, forest cover, or urbanization. For effective conservation action we need to know the distance within which these effects occur, i.e. the ‘scale of effect’ of the landscape. Predicting the scale of effect is also critical to landscape ecological research. If landscape variables are measured at the wrong extent, effects of landscape context can go undetected, and/or relative importance of landscape effects will be incorrectly estimated. Nevertheless, many researchers arbitrarily select a single spatial scale for analysis and others scale the landscape to the movement biology of the organism(s), on the reasonable assumption that the scale of effect depends on the spatial extent over which the organism interacts with its environment. Tests of this assumption so far have been mixed, indicating that other factors come into play. For example, how is the scale of effect influenced by demographic parameters (e.g., reproductive rate), by details of a species’ movement behaviour, and by species interactions? How does the scale change, depending on the landscape predictor (road density, forest cover etc.)? And, does it depend on the response measured, e.g., abundance, species richness? There is currently no comprehensive theory for predicting the scale of effect of the landscape context on population and community responses. OBJECTIVE: Over the next 5 years I aim to build and validate a set of hypotheses for predicting the scale of effect of the landscape context on population and community responses. APPROACH: I propose eight hypotheses, suggesting relationships between the scale of effect and (i) species traits (dispersal, reproduction rate, resource use, traits of natural enemies), (ii) response variables (abundance, occurrence, species richness), and (iii) type of landscape variable (acting through resource availability e.g. habitat amount, or through mortality e.g. road density). We will use individual-based spatial simulation modelling to evaluate the hypotheses and to estimate relative importance of factors influencing the scale of effect. We will then test the hypotheses by first (i) estimating the scale of effect of landscape predictors on multiple individual species and community responses, using multi-scale empirical studies, and then (ii) conducting cross-species (or species group) comparisons to test whether the observed scale of effect changes as predicted from the hypotheses and simulations. Since my goal is to develop a general, validated theory for predicting the scale of effect, we will conduct the empirical tests for several different species groups, including: forest small mammals, pond and forest dwelling amphibians, bark and wood boring beetles, forest floor plants, and alvar plants. SIGNIFICANCE: We know that selecting the ‘right’ spatial scale is hugely important in landscape and conservation ecology, but we generally ‘wing it’ because we do not know the right scale a priori. The proposed research will build validated theory that will allow landscape and conservation ecologists to select the right spatial scale for analyses and application. This will (i) increase inferential strength in landscape ecology studies and (ii) greatly increase effectiveness of landscape-scale conservation actions, ensuring that they are implemented at the correct spatial extent for best success in effecting conservation goals.