Habitat Suitability Evaluation Of Endangered Plants Based On Bayesian Network

In recent years, a series of qualitative or quantitative modeling approach is applied to establish habitat suitability models, these modeling methods require the sufficient investigation or almanac data to ensure model precision and accuracy, and Bayesian network (Bayesian network, BN) is a organic combination of Bayesian probability model and a directed acyclic graph network topology which has a low demand on the existing information, and can make a information reasoning under the incomplete and uncertainty information. Bayesian network can take the advantage of limited data to build a robust model which has a good intelligibility and logic, and can use literature, survey data and expert opinions to adjust the model parameters at any time.It is an effective integration and complementary of the expertise and test data, this method ignores minor contact, highlights the main contradictions and has a persuasive reasoning. Bayesian network has been more and more applied in establish habitat suitability model of rare and endangered species to provide reliable scientific basis for the establishment and management of protected areas of decision-makers.This study takes the rare and endangered plants Taiwania flousiana Gaussen for example, takes the southern region of China as the study area, collecting latitude and longitude data of Taiwania flousiana Gaussen, using climate, topography and soil data of the study area, this paper combines related analysis and random forest (RF) method to select evaluation factor and preliminary build the Bayesian network model, then according expert opinion, a large number of documents and decision theory to build a Taiwania flousiana Gaussen habitat suitability model.At the same time, according habitat suitability model to ratiocinate and discuss the uncertainty reasoning of Taiwania flousiana Gaussen suitable habitat and set up limit value of each evaluation factor to determine the extent of the Taiwania flousiana Gaussen growth factors, then combining the reasoning result with GIS technology to determine the Taiwania flousiana Gaussen suitable habitat spatial distribution in southern China, showing the analysis results in the visualizing form shows, providing scientific basis for the introduction and Taiwania flousiana Gaussen protection.The main conclusions of this study are as follows:(1)Taiwania flousiana Gaussen is affected by climate most among three environmental factors, i.e., climate, topography, soil. While the two factors, temperature and precipitation in climate, the latter one has more influence on the growth of Taiwania flousiana Gaussen, especially precipitation intensity in rainfall conditions is of a key component.(2)Among these three environmental factors, the pH(soil acidity) changes suitable habitat of Taiwania flousiana Gaussen to the greatest degree, followed by the ASPE (aspect) and Bio4 (seasonal changes coefficient in temperature) which also have great impacts. Because Taiwania flousiana Gaussen is hardy, Bio11 (mean temperature of coldest quarter) has smaller impact than the pH, ASPE and Bio4 these three factors, showing strong adaptability to low temperature. SOM (soil organic content) in completely above or below the average level, degree of suitable habitat changes of Taiwania flousiana Gaussen is 0.(3)Area in which Taiwania flousiana Gaussen can grow accounted for 60.8% of the total area in the study area(low, medium and high suitable habitat sum), where the high suitable habitat accounted for 16.3%, mainly distributing Nujiang River Basin in the western of Yunnan, the eastern of Nanpanjiang basin in the eastern of Yunnan, the south-central of Guizhou and Leishan which is a mountain in Guizhou southeastern, to the south of the Yangtze River in Hubei western, Jiufeng Mountains south section in the eastern of Fujian and western of Lancang River Basin in the south of Yunnan. The rainfall in these places is adequate and stable at between 1200 mm?1700mm, the annual average temperature is about 16?. The altitude of mountainous region is 1500 ?2000 m, the loam area whose soil is mainly mountain yellow acidic in these high suitable region.(4)Certain shade environment is better in the growth process of Taiwania flousiana Gaussen. Whole lighting or shade condition makes it failure to thrive, resulting in a decrease of suitable habitat area. Taiwan flousiana grows faster in hot and humid climate, the larger change of seasonal temperature is, the better Taiwan flousiana grows.