| The forest landscape is a composite ecosystem made up of multiple diverse forest communities within a geographical region.Landscape pattern is the distribution and composition of different landscape elements in geographical and spatial locations,representing the distribution characteristics and associated relationships of various landscape elements,and directly affect the social provisioning,ecological regulating,and biodiversity conservation functions of forest landscapes.The change of landscape pattern is affected by the combination of natural environment and human activities.Investigating the dynamics of landscape patterns helps us comprehend the function of numerous driving factors and their interrelationships,which is crucial for forest resource conservation and management.In this study,we investigated the dynamic evolution of forest landscape pattern in Maoershan farm by using area transfer matrix,landscape pattern index,forest age transfer matrix,and structural equation model with the forest inventory data in 1983,1993,2004,and 2016,analyzing the change patterns and driving factors,and proposing reasonable and effective management measures to further provide guidance and suggestions for sustainable forest management,the main research contents and results are as follows:(1)In 2016,the forest land accounts for 86.77%of the total area of the region,which is the basis of the forest farm landscape.The forest land landscape is dominated by soft broad-leaved mixed forest and hard broad-leaved mixed forest,the forest land landscape generally shows an upward trend.From 1983 to 1993,the landscape area of forest land decreases by378.6 hm~2,and the area increases by 1 730.8 hm~2 and 499.4 hm~2 during 1993-2004 and 2004-2016,respectively.Due to the influence of the natural environment and human disturbance,various types of vegetation in the forest land also have changed to varying degrees.Compared with 1983,in 2016,the area of soft broad-leaved mixed forest decreases by 1 183.20 hm~2,the poplar forest area increases by 1 618.89 hm~2,the hard broad-leaved mixed forest area increases by 1 457.07 hm~2,and the coniferous broad-leaved mixed forest area increases by 767.87 hm~2.The increased forest land mainly comes from 1 280.84 hm~2 of cultivated land,1 050.46 hm~2 of afforestation land,779.14 hm~2 of sparse forest land and 619.30 hm~2 of unused land,while the area of cultivated land transferred is the largest.(2)At the landscape level,the numbers of patch,patch density,patch shape index,Shannon diversity index and Shannon evenness index all decrease,while the patch association index and the maximum patch index increase,which indicates that the landscape fragmentation decreases and the distribution tends to gather.(3)There is a phenomenon of retention and transfer of forest age in natural forests.With the increase of age class,the retention probability of soft broad-leaved mixed forest increases with a 0.04 step difference,and the stand age vector is an arithmetic sequence with a tolerance of 0.04;the retention probability of mixed hard-broadleaf forests increases with a 0.06 step difference,and the stand age vector is an arithmetic sequence with a tolerance of 0.08.(4)From Phase I to Phase III,the total effects of natural factors(slope,slope position,and elevation)in the structural equation model are 0.3196,0.1685,and 0.1092,respectively,and the distance factors(distance from roads,rivers,and settlements)are 0.2712,0.2226 and0.2010,and the management measures are 0.2800,0.0300 and 0.0200 respectively.The distance factor has a significant and stable influence on the stand types,while the natural factors and management measures have a significant impact in the early stage,and gradually weakens in the latter two periods.The landscape area of forest land increases steadily,the landscape distribution becomes more concentrated and the landscape diversity decreases,natural and distance factors have a significant impact on forest types,and human factors promote the positive succession of forests. |
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