Severity: Warning
Message: file_get_contents(https://...@pubfacts.com&api_key=b8daa3ad693db53b1410957c26c9a51b4908&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 176
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 176
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 250
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 1034
Function: getPubMedXML
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3152
Function: GetPubMedArticleOutput_2016
File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
Understanding landscape pattern change and its response to anthropogenic disturbance is of great significance for ecosystem conservation and management. Based on high-precision land use data from 1980 to 2015, we studied the spatial and temporal changes of landscape patterns in the Qinling Mountains and its response to anthropogenic disturbance by using the landscape pattern vulnerability index and human disturbance degree constructed by the landscape pattern index and the surface coverage classification system. The results showed that the degree of landscape fragmentation gradually increased in the Qinling Mountains. The landscape shape became more complex, the degree of landscape aggregation and connectivity decreased, and the spatial distribution of the landscape pattern index showed distinct features of topographic differentiation from 1980 to 2015. The fragility of the landscape pattern in the Qinling Mountains was on a downward trend as a whole. The spatial pattern of the low-vulnerable region had changed significantly, which mainly expanded from Xi'an and Hanzhong to the surrounding areas. The degree of anthropogenic disturbance in the landscape pattern of Qinling Mountains gradually increased. The spatial distribution was "high in the east, low in the west, high in the north-slope, low in the south-slope, high on the periphery, low in the middle". The fragility of landscape pattern, patch density and Shannon diversity index increased with the increases of anthropogenic disturbance, while the aggregation index and maximum patch index decreased. In the past 35 years, the impacts of anthropogenic disturbance, which gradually weakened the vulnerability of landscape pattern, also increased Shannon diversity index and the largest patch index gradually, while it had not significantly changed the patch density and the aggregation index.
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Source |
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http://dx.doi.org/10.13287/j.1001-9332.201812.018 | DOI Listing |
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