[Evolution of Ecological Security Pattern in the Economic Belt of the Northern Slope of Tianshan Mountains Under...

Investigating and clarifying the mechanisms by which climate change influences ecological security patterns is an effective measure for maintaining ecological security. Based on this， the study region selected is the Tianshan North Slope Economic Belt， utilizing three typical climate scenarios from the sixth coupled model intercomparison project （CMIP6）： SSP1-1.9， SSP2-4.5， and SSP5-8.5. First， the patch-generated land use change simulation model （PLUS model） was used to simulate land use evolution under different climate scenarios by 2060. Based on this， the integrated assessment model for ecosystem services and trade-offs （InVEST model） was applied to assess four key ecosystem services： water production， soil conservation， habitat quality， and carbon storage. Additionally， morphological spatial pattern analysis （MSPA） and the patch importance index （DPC） were employed to identify ecological source. Next， the analytic hierarchy process （AHP） was used to determine the weights of seven indicators， including land use， topography， habitat quality， and climate factors， to construct an ecological resistance surface. Finally， ecological corridors were extracted based on circuit theory. The results indicate： ① Ecological source areas were spatially distributed with more in the south and fewer in the north， denser in the south and sparser in the north， concentrated in the forested and grassland areas north of the Tianshan Mountains. In 2020， the area was 76 807 square kilometers， and in the SSP245 scenario by 2060， it slightly decreased to 75 979 square kilometers， showing the highest stability. Under the SSP585 scenario， the source area decreased to 66 904 square kilometers， with the highest degree of fragmentation. Under the SSP119 scenario， it expanded to 80 031 square kilometers with the best connectivity. ② Under the SSP245 scenario， the total length of ecological corridors reached its maximum， increasing to 4 509 kilometers. Under the SSP585 scenario， degradation was severe， with the total length of corridors decreasing by 21.7%， while the number of corridors increased by 10， resulting in a fragmented ecological network characterized by "increased quantity but decreased quality." Under the SSP119 scenario， the total length of corridors was 3 592 kilometers， a slight increase of 5.4%， with the number of corridors decreasing to 81. The distribution structure of ecological corridors was optimized， with the most significant improvement in connectivity， highlighting the effectiveness of ecological conservation efforts. ③ Ecological pinch points increased in all three scenarios， with the most dramatic increase occurring in the SSP585 scenario， in which the number of hotspots increased by 235%， and the area increased by 15.91 square kilometers. The area of ecological barriers decreased in all three scenarios but remained large in the SSP585 scenario. Through SSP scenario comparisons， it was found that under the low-carbon scenario， source areas and corridor networks were expanded and strengthened， indicating that low emissions are beneficial for ecological stability； however， under the high-emission scenario， source area sizes decreased， ecological resistance increased， corridors became fragmented， and the vulnerability of the ecological security pattern rose.