As global climate change continues, the frequency and intensity of compound dry-heat events have significantly increased on both global and regional scales, exerting notable impacts on vegetation physiological activities. However, current studies mostly focus on the impacts of individual drought or heat events on vegetation while often neglecting the stress from compound dry-heat events. This study utilized monthly Standardized Precipitation Index (SPI), Standardized Temperature Index (STI), Compound Drought and Heat Index (CDHI), and Normalized Difference Vegetation Index (NDVI) from 1982 to 2015 to investigate the impacts and time-lag effects of different climatic conditions on vegetation during the growing season. The results revealed the following: (1) Compound dry-heat conditions generally promote vegetation growth at higher latitudes but suppresses it at mid-to-low latitudes. Additionally, as humidity increases, the effect of compound dry-heat conditions on vegetation shifts from suppression to promotion. Regarding different vegetation types, compound dry-heat conditions generally inhibit herbaceous plants while promoting woody plants. (2) The average lagged time of compound dry-heat and heat conditions events on vegetation is relatively short (1.1±1.8 and 1.1±1.9 months, respectively), whereas drought conditions exhibit a longer lagged time (2.8±2.1 months). The lagged time of all events varies with humidity levels. However, in different extreme climate events, the lagged time of compound dry-heat events is longer and comparable to that of drought events, while heat events have a relatively short lagged time, with no significant variation across different climate zones. In summary, this study comprehensively analyzes the impact of different climatic conditions on vegetation and their time-lag effects, providing a scientific basis for understanding vegetation dynamics under climate change.

The recently proposed Species-Area-Isolation hypothesis for global species richness distribution suggests that climate and climatic geography (i.e., the spatial distribution of climatic conditions, including climatic area and climatic isolation) can explain 90% of global species richness patterns, with larger and more isolated climatic conditions typically supporting higher species richness. However, it remains unclear whether this global pattern applies to regional species richness distributions. This study uses the Qinghai-Xizang Plateau, a unique geographic and climatic region, as a case study, employs generalized additive models (GAMs) based on climatic space to investigate the influence of climate and climatic geography on species richness patterns on the Qinghai-Xizang Plateau. The results indicate that: (1) The Species-Area-Isolation hypothesis applies to species richness distribution on the Qinghai-Xizang Plateau, suggesting its broader applicability. Considering climate and its geographic attributes, the model explains 85% of the animal species richness distribution and 80% of the plant species richness distribution on the Qinghai-Xizang Plateau. (2) Larger and moderately isolated climatic conditions support greater species richness, with climatic isolation showing a dual mechanism: moderate isolation (mean Euclidean distance between geographic fragments within climatic units < 500 km) increases richness, while high isolation (> 500 km) reduces it. (3) Climate is the primary factor influencing species richness distribution on the Qinghai-Xizang Plateau, while the independent effect of climatic geography is relatively minor. However, its interaction with climate is significant for certain taxa, explaining 25%, 12%, and 22% of the spatial variation in mammal, amphibian, and plant species richness, respectively. This study provides a regional empirical case for the Species-Area-Isolation hypothesis and offers a theoretical foundation for the conservation of regional species richness.

National Parks play a crucial role in achieving the scientific protection and rational utilization of natural resources. Under risks of climate change and human interference, detecting and monitoring the evolution of national park ecological resilience is a key cornerstone for ensuring regional sustainable development. Based on the construction of the ecological resilience assessment framework of "resistance-adaptivity-resilience" and the method framework of "highlands identification - resistance surface construction - corridor extraction", this study examines the spatio-temporal pattern and network of ecological resilience in Northeast China Tiger and Leopard National Park from 2017 to 2022. The results show that in this national park, each dimension of ecological resilience exhibits varied levels, with resilience dimension showing the highest and most stable level. The spatial heterogeneity of ecological resilience is significant, with the spatial characteristics closely related to geographical environment and human activities. The valley area, which accounts for 13.85% of the total area of the region, is the area with intense human activities and weak ecological resilience. A turning point appeared in the year of 2019, as the construction of national park promoted the change of ecological resilience from active interaction to non-interference adaptation pattern, signaling a prominent positive overall trend. The ecological resilience network system has significant hierarchical characteristics, with a total length of 4603 km of internal ecological corridors, and the radiating effect is gradually increasing. To enhance ecological resilience, it is fundamental to strengthen ecological corridor network connection and improve self-organizing adjustment ability of ecological resilience system to cope with risk interference. Through the construction of ecological resilience assessment framework, this study helps to effectively integrate the spatiotemporal processes of ecological resilience and ecological networks from a theoretical perspective, realize the organic connection of "surface-line" in the study of ecological resilience of national parks, and provide theoretical support for the formulation of ecological environmental development strategies for national parks, so as to promote regional sustainable development and efficient coordination of multiple factors.