Integrated geographical environment factors explaining forest landscape changes in Luoning County in the middle reaches of the Yiluo River watershed, China

Abstract

Analysis of forest landscape changes and its driving factors is vital to forest ecosystem management and sustainable development. However, it is difficult to integrate various environment factors and explain the change of forest landscape. Research on the impact of integrate geographical environment factors on forest landscape changes is still lacking. In this study, we quantified forest area and mapped forest landscape distribution in 1990, 1995, 2000, 2005, 2000, 2010, and 2015 in Luoning County in the middle of the Yiluo River watershed by using multi-temporal land use data, and detected spatio-temporal changes of the forest landscape. Three types of forest landscape changes (unconverted, reforestation, and deforestation) and ten geographical environment factors (elevation, slope, proximity to previous forest edge, distance to rivers, mean annual temperature, mean annual precipitation, distance to roads, distance to residential centers, population density, Gross Domestic Product) were identified. Pearson correlation analysis and line regression analysis were applied to examine the relationships between forest landscape changes and geographical environment factors. Based on the relationships, correlation coefficient and adjusted R2, these environment factors were formed into an integrated geographical environment factors index (IGEF), and an approach for analyzing forest landscape changes along the geographical environment factors gradient was proposed. The results showed that: (1) the total area of forest landscape decreased from 1990 to 2000 and continued to increase from 2000 to 2015; (2) reforestation and deforestation were closely related to individual geographical environment factors and IGEF index; (3) reforestation and deforestation mainly occurred in the areas with low and medium IGEF index values, while forest landscape unconverted was mainly distributed in the areas with high and medium IGEF index values. The observed forest landscape changes could be explained by a set of given geographical environmental factors. Our findings are expected to enhance the understanding of integrated analysis method of geographical environmental factors and contribute to the targeted forest landscape management in mountain areas.