Habitat quality degradation in Chinese nature reserves has been mitigated—based on habitat quality observations from 2010 to 2020

Systematic assessments of the habitat quality (HQ) of nature reserves (NRs) and revealing the driving factors of their progress and degradation have become a focus of global biodiversity conservation. China has established a state-led nature reserve management system. Comparative analyses of biodiversity conservation effectiveness across different types of nature reserves are still insufficient, and there remains a lack of adequate evaluation concerning the mitigation of disturbances. We analyzed the spatiotemporal variation characteristics of HQ in Chinese NRs from 2010 to 2020. We revealed differences in HQ across various administrative levels, types and geographical regions of NRs and analyzed the driving factors of HQ changes. The results showed that: (1) during the study period, the overall HQ of Chinese NRs exhibited a downward trend; however, this trend slowed down during the second periods (2015–2020), likely due to strengthened conservation measures. (2) Spatially, HQ was low in the west and high in the east. Except for the northwestern, eastern and southwestern regions, NRs in other regions showed a downward trend in HQ, with the northeastern region declining the most. (3) Compared with provincial NRs, the national NRs presented a lower decrease in HQ. Among the main types of NRs, the degree of HQ decline decreased in the following order: natural heritage type (NHT) > natural ecosystem type (NET) > wildlife type (WT). Therefore, we need to focus on the management and policy support for NRs with severely declining HQ, such as provincial NRs and natural heritage type NRs, as this is key to preventing the overall decline in HQ. (4) HQ degradation was affected mainly by changes in the Land Use Degree (LUD) index and minimum temperature. HQ improvement was affected mainly by the LUD change. These findings indicate that rational land use is still an important factor for the sustainable development of NRs. And we should pay attention to NRs located in areas susceptible to abnormal or fluctuating minimum temperatures. This study provides a scientific basis for the macro planning and quality improvement of Chinese NRs conservation in the future.