A Generic Shallow Lake Ecosystem Model Based on Collective Expert Knowledge
A Generic Shallow Lake Ecosystem Model Based on Collective Expert Knowledge
复制标题
基于集体专家知识的通用浅湖生态系统模型
DOI：
10.1007/s10750-005-1397-5
复制
发表时间：
2006
期刊：
影响因子：
2.6
通讯作者：
Uygar Özesmi
中科院分区：
文献类型：
--
作者：
C. Tan;Uygar Özesmi
我们使用模糊认知映射（FCM）开发一个通用的浅水湖泊生态系统模型，通过增强个人的认知地图绘制的8位科学家在浅水湖泊生态学领域的工作。我们计算了个人认知地图和集体认知地图增强产生的图论指数。集体认知图共有32个变量，113个连接。图论指数揭示了浅水湖泊生态系统的非线性动态的内部循环。生态过程是民主组织的，没有自上而下的等级结构。集体地图中最核心的变量是沉水植物。最强的连接是悬浮固体浓度降低水的透明度，磷浓度增加浮游植物生物量，更高的水的透明度增加沉水植物，底栖鱼类生物量减少沉水植物和增加悬浮固体浓度，沉水植物减少悬浮固体。通用模型的稳态条件是典型的浅水浑浊湖泊生态系统。一般浅水湖泊生态系统模型有进入浑浊状态的趋势，因为没有动态环境变化，可能会导致之间的转变浑浊和清水状态，和一般模型表明，只有动态扰动制度可以保持清水状态。本文开发的模型捕捉浅水湖泊的经验行为，并包含替代稳定状态理论的基本模型。此外，我们的模型扩展了基本模型，量化了连接的相对影响，并将其扩展为22个变量和99个加权因果连接。使用我们的扩展模型，我们运行了4个模拟：收获沉水植物，营养减少，在不减少营养的情况下去除鱼类，以及生物操纵。只有生物操纵，其中包括鱼类的去除和营养盐的减少，有可能将浑浊状态转换为清水状态。结构和关系的通用模型，以及管理模拟的结果支持在浅水湖泊生态系统的实际实地研究。因此，模糊认知映射方法，使我们能够了解浅水湖泊生态系统的复杂结构作为一个整体，并获得一个有效的通用模型的基础上，专家在该领域的隐性知识。
We used fuzzy cognitive mapping (FCM) to develop a generic shallow lake ecosystem model by augmenting the individual cognitive maps drawn by 8 scientists working in the area of shallow lake ecology. We calculated graph theoretical indices of the individual cognitive maps and the collective cognitive map produced by augmentation. There were a total of 32 variables with 113 connections in the collective cognitive map. The graph theoretical indices revealed internal cycles showing non-linear dynamics in the shallow lake ecosystem. The ecological processes were organized democratically without a top-down hierarchical structure. The most central variable in the collective map was submerged plants. The strongest connections were suspended solids concentration decreasing water clarity, phosphorus concentration increasing the phytoplankton biomass, higher water clarity increasing submerged plants, benthivorous fish biomass reducing submerged plants and increasing suspended solids concentration, and submerged plants decreasing suspended solids. The steady state condition of the generic model was a characteristic turbid shallow lake ecosystem. The generic shallow lake ecosystem model had the tendency to go into a turbid state since there were no dynamic environmental changes that could cause shifts between a turbid and a clearwater state, and the generic model indicated that only a dynamic disturbance regime could maintain the clearwater state. The model developed herein captured the empirical behavior of shallow lakes, and contained the basic model of the Alternative Stable States Theory. In addition, our model expanded the basic model by quantifying the relative effects of connections and by extending it with 22 more variables and 99 more weighted causal connections. Using our expanded model we ran 4 simulations: harvesting submerged plants, nutrient reduction, fish removal without nutrient reduction, and biomanipulation. Only biomanipulation, which included fish removal and nutrient reduction, had the potential to shift the turbid state into clearwater state. The structure and relationships in the generic model as well as the outcomes of the management simulations were supported by actual field studies in shallow lake ecosystems. Thus, fuzzy cognitive mapping methodology enabled us to understand the complex structure of shallow lake ecosystems as a whole and obtain a valid generic model based on tacit knowledge of experts in the field.