The foraging strategies of sympatric ungulates with similar ecological niches are important for understanding ecological niche differentiation, resource utilization, competition, and coexistence and for understanding the ecological impacts on plant communities in the ecosystem. The behavior of the wapiti (Cervus elaphus) and Siberian roe deer (Capreolus pygargus) foraging on Japanese yew (Taxus cuspidata) has affected its succession and renewal in the northeastern forests of China, which has become an urgent problem for the relevant departments. This study analyzed the foraging strategies of the wapiti and Siberian roe deer on Japanese yew from July 2021 to January 2024 using field investigations and infrared camera monitoring in the Muling National Nature Reserve, Heilongjiang Province, China. It was found that the wapiti and Siberian roe deer have different foraging strategies in terms of time, space, and behavior. Temporally, they both preferred to forage for the saplings of the Japanese yew during the winter season, the degree of overlap in foraging rhythms was medium (Dhat1=0.67), and the diurnal foraging activity index (DRAI) of the wapiti was larger than that of the Siberian roe deer. Spatially, the suitable foraging habitat of the Siberian roe deer was twice that of the wapiti, and their overlap was low in the location and direction of saplings and the distance of the seed tree. Behaviorally, the foraging intensity of the wapiti was heavy, and Siberian roe deer was low. Foraging reduced the average primary branch height, number of new branches, and length of lateral branches of saplings, and the influence of the wapiti was significantly greater than that of the Siberian roe deer. This study provides a scientific basis for solving the conservation and management problems of the deer animals foraging on Japanese yew and contributes to further understanding of the competition-coexistence mechanism of sympatric species.

1. Many policies and studies globally have highlighted the pivotal role of wetland ecosystems regarding wetland biota and their ecological status. With the strengthening of wetland ecosystem management legislation and policy, wetland restoration should also consider increasing habitat diversity to improve biota. We explore whether the construction of artificial ecological islands can increase the diversity of wetland birds and macroinvertebrates before assessing the effects of actively constructing islands via human intervention on wetland protection. 2. We discuss changes in waterfowl and macroinvertebrate diversity (i) with and without islands, (ii) at different water level gradients surrounding the islands, (ⅲ) on different island substrates, and (ⅳ) at different time scales. We used ANOVA, ANOSIM and cluster analysis to test the differences. 3. The waterfowl and macroinvertebrate communities had spatially heterogeneous distributions and vary over time due to both natural and anthropogenic stresses. The establishment of islands significantly changed the community composition and biodiversity of the macroinvertebrate and the waterfowl. The waterfowl and macroinvertebrate communities had different compositions at different water levels. Macroinvertebrates are the main food components of waterfowl and are closely related to them, and overall, abundance and diversity of macroinvertebrates directly and/or indirectly affect the biodiversity of waterfowl. Potentially, the construction of islands could provide some co-benefits for the conservation of wetland birds and macroinvertebrates. Synthesis and applications. Establishing artificial ecological islands in broad open water areas and increasing the water level gradient and substrate diversity. It can increase the micro-habitat diversity by artificially increasing the heterogeneity of the water depth conditions of a habitat. These changes can accommodate aquatic organisms with different ecological niches to increase the biodiversity, affecting the ecological restoration of inland freshwater marshes and wetlands. As such, wetland parks can play a positive role in protecting important bird migration pathways in northeast Asia.