Effectiveness of Heilongjiang Nanwenghe Nature Reserve in Improving Habitat Quality in and around the Reserve

Abstract Biodiversity loss is a critical challenge globally, and protected areas (PAs) has been established as an important policy tool for conservation. However, doubts exist regarding their effectiveness, and their policy effects and spatial spillover effects on surrounding areas are poorly understood. To address this, this study evaluated the effectiveness of Heilongjiang Nanwenghe National Nature Reserve (HNNNR) in China by using a combination of the InVEST model and the improved SDID model. The study covers a time span of approximately 31 years (1990–2020) and is divided into two periods (1990–1999 and 1999–2020), which allows for the assessment of the effects of nature reserves in the region. Our results showed that: (1) The establishment of HNNNR has improved the habitat quality in the reserve and Non-reserve area, with a greater impact on habitat quality in non-reserve areas than in the reserve; (2) The core zone within HNNNR showed the most significant improvement in habitat quality, while the buffer zone showed the least improvement; (3) The improvement of habitat quality in non-reserve area was mainly contributed by the policy spatial spillover effects, where the buffer zone has the strongest spillover benefits to the non-reserve, but the core zone has the weakest spillover effects to the non-reserve. Our results show the beneficial impact of a nature reserve for improving habitat quality in and around the reserve. This study provides a quantitative paradigm for assessing the conservation effectiveness of PAs across temporal and spatial scales.