基于椭圆脐点突变模型的大熊猫生存状态研究

得益于有力的保护,大熊猫受威胁等级由"濒危"降为"易危"。根据全国大熊猫调查数据,近年来,大熊猫野生种群与栖息地面积总体上均处于持续增加态势;同时,大熊猫栖息地破碎化与局域种群隔离也呈加剧的趋势。两相对比,形成悖论现象,难以正确认知当前大熊猫的生存状态。大熊猫作为高度特化的K对策大型动物,其生存高度依赖于栖息地生态系统,极易受栖息地丧失与破碎化的影响。对大熊猫生存状态的研究,不应局限于栖息地或种群等单项指标的变化,而应基于系统科学的整体视角。结合全国第三、四次大熊猫调查数据,对大熊猫野生种群数量与栖息地及潜在栖息地的面积进行复相关分析,发现大熊猫野生种群数量与栖息地、潜在栖息地的面积之间存在着高度显著正相关,表明三者之间存在着稳定而密切的耦合关系,进而建立了大熊猫种群与栖息地、潜在栖息地之间的耦合函数。突变理论作为一种成熟的系统科学理论,提供了较完备的数学方法,利用系统中少量的关键指标便可实现对系统行为的刻画。基于突变理论,以大熊猫分布区生态系统为研究对象,选取了大熊猫种群数量、栖息地与潜在栖息地的面积为系统关键指标,利用种群与栖息地、潜在栖息地之间的耦合函数,构建了"大熊猫—栖息地"系统椭圆脐点突变模型,对生态系统的稳定性进行研究。发现虽然野生种群数量、栖息地与潜在栖息地的面积均持续增长,但严峻的局域种群生存危机与栖息地的高度破碎化,从总体上削弱了系统的稳定性,大熊猫分布区生态系统的稳定性处于持续下降态势,且濒临系统临界状态,生态系统具有较大的退化压力,大熊猫的生存危机依然严峻。

Survival status evaluation of giant panda based on elliptic catastrophe model

Owing to strong protection measures, the threat to giant pandas was reduced from "endangered" to "vulnerable" by the IUCN in 2016. In recent years, national surveys of giant pandas revealed that the wild populations and habitat areas had increased constantly. However, habitat fragmentation and population isolation have become a more serious threat. Therefore, it is difficult to evaluate the current survival state of pandas accurately, although this is necessary for their protection. As a highly specialized animal utilizing the K-strategy, pandas are strongly dependent on their habitat ecosystems, and vulnerable to habitat fragmentation and population isolation. Therefore, the survival status of giant pandas should be evaluated from the perspective of the ecosystem. Based on the third and fourth national survey data, a multiple correlation analysis of population size with area of habitat and potential habitat was performed. We found a highly significant correlation between giant panda populations and habitats, implying that habitat conservation was the key to panda protection, and that there was a stable and close coupling relationship between wild populations and habitats. From the perspective of panda protection, this correlation constituted the basis for studying the ecosystem and designing ecosystem models. As a mature theory of systems science, the catastrophe theory provides a method of constructing system models with several key indices in the system, which can ignore the internal mechanism of the system. Considering the ecosystem of the distribution area of giant pandas as the research object, the number of wild pandas, and the area of the habitat and potential habitat as the key indices, the catastrophe theory was applied to this ecosystem. Moreover, the catastrophe potential function of the ecosystem was constructed, and the elliptic catastrophe model was derived. We found that, although the habitat area and number of wild populations continued to grow, the severe local population survival crisis and habitat fragmentation had generally weakened the systems'' stability. The stability of the ecosystem is decreasing gradually and is very close to a critical state. Therefore, the ecosystem is still being subjected to great degradation pressures, and the survival crisis of giant pandas remains serious. Based on the current population and their habitat status, we suggested that all habitats needed to be protected effectively in the short-term. In addition, considering each large habitat as the center, corridors need to be constructed to connect the large population with surrounding small populations. In the long-term, more corridors need to be designed and constructed to expand the "star" network into a complex network, which will effectively withstand any disturbance. The catastrophe theory and its mathematical models were based on the entire system, and they included the relationships between the key elements, rather than solely on a few indices. This theory provided a coherent framework for modeling the complex dynamics of ecosystems. There are seven elementary catastrophes and corresponding models in the catastrophe theory, which have various potential applications. In addition to the evaluation of risk for biodiversity and the ecosystem, it has universal applicability in the study of ecology and as a methodology of system analysis.