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
To maintain ecosystem functions and ensure ecological security, estimating the value of ecosystem services and constructing an ecological security pattern are necessary. Considering the lack of systematic research on the estimation of ecosystem service value and the construction of ecological security pattern, this study extracted the ecological source based on the analysis of ecosystem service value and morphological spatial pattern. According to the natural conditions such as geographical location and altitude, land use type, landscape pattern type, elevation, slope, and normalized difference vegetation index were selected to establish the resistance surface. The minimum cumulative resistance model was used to identify potential ecological corridors, so as to construct the ecological security pattern of Heilongjiang Province, and longitudinal analysis was conducted from 2000 to 2020. The results showed that: ① The overall value of ecosystem services in Heilongjiang Province showed an upward trend (with an amplitude of 42%), the value of hydrological regulation services accounted for the largest proportion among different service types (approximately 30%), and the value of forest land services accounted for the largest proportion among different land use types (up to 70%). ② Eight ecological source areas were extracted, mainly distributed around Greater Khingan Mountains, Lesser Khingan Mountains, Changbai Mountain, and Wanda Mountain, with the largest area of ecological source in Greater Khingan Mountains. ③ Twenty-eight potential ecological corridors were identified, mainly distributed in the northeastern side of the line from Heihe City to Mudanjiang City, forming densely populated areas in Qitaihe City, northern Mudanjiang City, and southern Jixi City. ④ An ecological security network pattern in Heilongjiang Province was constructed with Greater Khingan Mountains Region, Mudanjiang City, and Shuangyashan City as endpoints and Yichun City as the center, finding that the main problem faced at that time was uneven spatial distribution. The research results are helpful to formulate and establish more reasonable ecological environment protection measures and policies and can provide reference value and scientific basis for provincial ecosystem protection and optimization.
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http://dx.doi.org/10.13227/j.hjkx.202312122 | DOI Listing |
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