Taxus cuspidata is a rare and endangered plant species with an extremely small population which is endemic to China. This study focused on the natural T. cuspidata population in Jilin Province in China. Conventional population ecology survey methods were used to describe its population structure characteristics. Then, we chose diameter structure instead of temporal structure to establish a static population life table, draw a population survival curve, and quantify the future development trend by using population dynamic analysis and time sequence prediction. The results showed that: (1) the static life table suggested that the population of T. cuspidata was stable overall. The population survival curve tended to be Deevey Ⅱ, with a high early seedling mortality, and the later population growth tended to be stable; (2) the survival curve suggested that the population initially experienced higher mortality rates in the early stage. However, as time progressed and the population aged, the mortality rates decreased, resulting in a more stable population in the middle and late stages; (3) The diameter class structure of T. cuspidata was stable overall, and the dynamic indices showed that the population was fluctuating. The population was influenced by external disturbances and showed some resistance to human disturbance; (4) time sequence prediction analysis showed that the mortality rate of young individuals was high, natural renewal could be maintained, and the population size would remain at a certain amount in the future. The result shows that the Jilin region is a highly suitable area for the growth of Taxus cuspidata’s population in Northeast China. We recommend in situ conservation of remaining wild populations, relocation of germplasm resources, and reduction of human activities; these actions will be beneficial to Taxus cuspidata’s long-term survival.

Biodiversity loss has accelerated over decades and probably exerted adverse impacts on ecosystems. As a key forest ecosystem function, tree productivity and its relationship with the change in species diversity are a hotspot in ecology research. However, the changing patterns of the relationships between these two variables across ecosystems with different environmental conditions and the underlying mechanisms are not well understood but key to make environmental context-specific strategies for forest ecosystem conservation and management. Here, we examined changes in relationship (R_DI-AGB) between the tree species diversity index (DI) and aboveground biomass (AGB) across temperate forest ecosystems with different environmental contexts on a small spatial (plot) scale as well as clarified the driving mechanisms using ground-based data from 3 natural reserves in northeastern China, surveying 22,139 trees across 77 species and 185 plots. We found substantial changes in R_DI-AGB across natural reserves with different environmental conditions on a small spatial scale. These changes were probably modulated by site-specific factors. A positive R_DI-AGB was attributed to positive impacts of local climate conditions (i.e., mean annual temperature and potential evapotranspiration) and stand age on both DI and AGB, which was observed in the Changbai Mountains Natural Reserve. In contrast, a negative R_DI-AGB was likely due to opposite directions in the effects of the site-dependent factors (elevation, mean annual precipitation, vapor pressure deficit, and seasonality of temperature) on DI and AGB, appearing in the Honghuaerji Natural Reserve. In addition, complex impacts of site factors on DI and AGB leading to no obvious R_DI-AGB was observed in the Shengshan Natural Reserve. Our results highlight the importance of site-dependent factors in modulating species diversity–productivity relationships and the need to use site-specific strategies in management and conservation for forest-dominated natural reserves and other forest ecosystems with heterogeneous environmental conditions.

Vaccinium uliginosum (VU) is one of the most precious wild berry plants distributed in the Changbai Mountain region in northeast China. Eight key morphological traits of VU were analyzed to examine the variation among and within five natural populations at different altitudes, as well as their response to environmental factors. The study results showed an increasing trend of variation among populations with ascending altitudes, but the range variation within populations exhibited a decreasing trend. The diversity level among populations was found to be higher than that within populations, and the five populations of VU were classified into four groups. Except for leaf width and twig length, all other morphological traits demonstrated significant or extremely significant correlations. Generally, with increasing altitude, leaf length decreased, while plant height, clear bole height, and basal diameter decreased significantly, and similar trends were observed with moisture factors, while a significant positive correlation was found with temperature factors. Among them, the morphological traits of clear bole height and basal diameter exhibited the strongest correlation with environmental factor variations. Overall, these findings indicate extensive variation in the morphological traits of VU within and among populations at different altitudes, with clear responses to changes in environmental factors.