ISWC OpenIR  > 水保所知识产出(1956---)
延河流域地带性物种分布对气候变化的响应研究
陈淑娟
Subtype学士 ; 硕士
2011-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword气候变化 物种空间分布模拟 Gam模型 生态位漂移 生境 延河流域
Abstract

作为气候变化的敏感区,黄土高原地区的气候变化对植被分布可能会产生重要影响。科学认识现有植被分布格局与当前气候等环境之间的关系,研究未来气候变化下植被分布格局,阐明不同物种生态适宜性对气候变化的响应趋势,建立未来植被分布格局的参照系统,对黄土高原未来植被恢复与重建具有重要的指导意义。本文以黄土丘陵区延河流域为研究区,通过研究该区残存自然植被与环境的关系,建立相应的物种分布模型,模拟和预测该区当前气候条件下和2050年各气候变化情景下的植被潜在分布,揭示主要地带性物种生态位中心对未来气候变化的响应规律,在此基础上探究揭示物种分布对气候变化的响应的研究方法,以期为更大尺度的植被分布与气候变化关系研究提供理论与方法等方面的探索。研究取得的主要结果有:
1)采用非线性建模途径(广义相加模型General Additive Model),为延河流域23个物种建立了广义相加模型,模型验证表明,ROC值均在0.7以上,cvROC值也在0.6以上,建立的模型符合统计要求。以物种分布模型为基础,结合统计工具与地理信息系统软件,通过对各预测变量的模型运算,预测了23个物种的空间分布。
2)通过所建立的物种分布模型,预测各气候情景下地带性物种空间分布,结果表明,气候变化将引起地带性物种空间分布格局的变化。温度升高2.5 ℃,降雨增加15% 将导致物种分布边界北移,有些物种甚至向北迁移出延河流域。
3)气候变化引起物种生境改变,导致物种生态位中心漂移,本论文研究了物种生态位中心在年均温和年均降雨量两个环境梯度上的漂移情况,结果表明,随着温度增加或降雨增加,物种生态位中心向较高温度或较大降雨处漂移。但不同物种漂移程度不同,生境要求较高的物种响应更加强烈,在温度梯度和降雨梯度上,物种生态位中心最大漂移分别可达3.55 ℃和75 mm。
4)与传统的通过物种分布边界或物种分布面积的变化揭示物种分布对气候变化的响应方法相比,物种生境变化百分比更能够敏锐揭示气候变化对物种空间分布的影响,该方法既能体现物种分布面积的变化,又能体现物种生境得失的具体情况。物种生境变化百分比能探测到物种空间分布格局的微小变化,快速准确察觉物种分布对全球气候变化的响应,可为应对全球变化可能引起的不良后果,及时采取措施减轻气候变化对生态系统的影响提供决策支持。
5)通过物种潜在分布面积与物种生境变化百分比的关系分析,表明在黄土丘陵沟壑区,由于地形因子对物种分布有着举足轻重的作用,因此与广域物种相比,分布范围较窄的物种对气候变化的响应更加敏感这一生态学理论不适于地形复杂的黄土丘陵区,物种分布范围大小并不能够指示物种分布对气候变化的敏感性响应。
关键词:气候变化 物种空间分布模拟 GAM模型 生态位漂移 生境 延河流域

Other Abstract

Loess Plateau, with fragile ecological environment, is very sensitive to climate change. Climate change may cause changes in vegetation structure and productivity and create opportunities for niche differentiation when empty niches are created at rear edges of range shifts. Moreover, the climate change will lead to more notable changes in species distribution and a more significant shift in realized niche due to the complex topography in the loess Plateau. Conservation managers must be able to detect measure and accurately predict such impacts of climate change on species in order to mitigate impacts on biodiversity and ecological restoration. This paper will try to address this problem through a case study in Yanhe River Catchment, aiming at studying the relations between remnant natural vegetation and environment, and building prediction models for different species. Combining with GIS spatial analysis, to predict the zonal species distribution in Yanhe River catchment and quantify the drifts of species niche center in main environmental gradients under six climate change scenarios in 2050, aiming at providing a simulated reference system for the planning and decision-making under climate changes in natural conservation and ecological restoration and studying methods accurately detecting species responses to climate change. As an initial work in this area, the author hopes that this work can provide scientific implications for ecological restoration under climate change scenarios in Yanhe River catchment, and experiences in methods and model building for studies in large scale. Here are the main outputs.
1) Based on the sampling plan according to stratification sampling and random sampling strategies, this paper collected 265 sample plots. It can meet with the requirement of building GAM(generalized additive models)model. Based the model building on the equilibrium theories, which assumed that the vegetation is in a relative equilibrium with environment, GAM models were built for 23 zonal species. The minumum of ROC validation of these models is 0.7, and cvROC is 0.6. Validation of these models showed that established models are sound in terms of statistic terms. According to the established  GAM models, this paper mapped 23 species’ distribution in Arcview using GAM models and lookup tables produced in S-Plus.
2) Based on the established GAM models, this paper predicted zonal species’ distribution under climate change scenarios. In general, our results showed that climate change would cause change in the distribution of endemic species. Following temperature increase, most species shifts to the higher latitude and some of these species shift their ranges out of Yanhe River Catchment.
3) Climate change will create opportunities for niche differentiation when empty niches are created at rear edges of range shifts. It will cause niche shift under climate change scenarios. The results showed that the species niche center drift to higher temperature gradient; Species distribution has the same response to climate change in precipitation gradient. But different species responded differently to climate change, Species with restricted ranges are more likely to be sensitive to climate change than widespread species. Concerning the temperature gradient and precipation gradient, the result shows a significant shift in response optimum 3.55 and 75℃ mm under climate changes scenarios. Species that encounter a broader array of climatic conditions across their range shows inconspicuous shift in envioroment gradient.
4) Compared to the general methods which study the sensitivity of species to climate change, calculated each species’ the percentage of range expansion or contraction can immediately detect the responses of species to climate change. Analysis the percentage of range expansion or contraction can reveal the change of species distribution area and calculate species habitat loss and gain. It can detect and accurately predict species distribution changes in order to mitigate impacts on regional species protection or ecological restoration.
5) Analyzed the relationship between the species potential distribution area and the percentage of stable suitable habitat and percentage of potentially new suitable habitat, the results showed that the ecology theory that generalist species should have broader tolerances to climate changes than specialist species didn’t sound in the Loess Plateau where topography is very important to species distribution. Species distribution ranges can’t reflect the sensitivity of species reponse to climate change.
Key words: Climate change; Prediction and simulation of potential species distribution; GAM model; Niche shift; Species habitats; Yanhe River Catchment

Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/8892
Collection水保所知识产出(1956---)
Recommended Citation
GB/T 7714
陈淑娟. 延河流域地带性物种分布对气候变化的响应研究[D]. 北京. 中国科学院研究生院,2011.
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