Potentially differential impacts on niche overlap between Chinese endangered Zelkova schneideriana and its associated tree species under climate change

Abstract

Climate change has a significant impact on the potential distribution for endangered trees. However, to date, little is known about how the endangered trees and main associated ones in different types of subtropical forests respond to climate change. Here, we first selected the endangered Zelkova schneideriana endemic to China and its associated trees as focus species from two subtropical forest communities (i.e. deciduous broad-leaf forest, bamboo and broad-leaf mixed forest) in China, and divided them into two species pairs: Z. schneideriana vs. Celtis sinensis, and Z. schneideriana vs. Phyllostachys edulis. Then, we simulated the three species’ suitable areas under current and future climate scenarios using Maxent based on the occurrence records and environmental variables, and further measured niche overlap between each species pair over time. Our Maxent showed: (1) Temperature-related factors have greater influence on Z. schneideriana than the other factors. The most important factor influencing its population distribution was Min temperature of coldest month (Bio6), followed by Mean diurnal range (Bio2), with the total contribution of 78.9%. (2) Currently, the suitable area of Z. schneideriana was predicted to be 106.50 × 104 km2, mostly located in the subtropical region of China, especially in Anhui, Hubei, Hunan, Jiangsu, and Zhejiang provinces. (3) Its suitable area would decrease and its average migration distance was 19.72 km under 16 future climate scenarios, with the core distribution migrating northeast. (4) There is an asynchrony of potential niche overlap between species pairs. One species pair with C. sinensis will rise in terms of Schoener’s D and I values whereas the other one with P. edulis will decline in the future. This asynchrony can be ascribed to the different future suitable ranges of these focus species as well as their ecological characteristics. Our study provides a new perspective on the conservation for endangered trees and surrounding neighbors in Chinese subtropical forests.

Impacts of Climate Change on the Biogeography and Ecological Structure of Zelkova schneideriana Hand.-Mazz. in China

“…Among all climate variables, Bio6 (minimum temperature of the coldest month) and Bio2 (mean diurnal temperature range) have the greatest impact on the distribution of Zelkova schneideriana . This finding aligns with Zhou et al’s previous study [ 23 ]. Zhou et al suggested that the ample precipitation in subtropical regions is unlikely to be a limiting factor for the distribution of Zelkova schneideriana .…”

“…Over time, the distribution range of Zelkova schneideriana in both climate scenarios is expected to face contraction, consistent with previous findings [ 23 , 26 ]. In subtropical regions of China, variations exist in the trends of changes observed in plant distribution areas.…”

“…Additionally, our study reveals a potential expansion of Zelkova schneideriana ’s distribution range towards higher latitudes and elevations, accompanied by a reduction in lower latitudes and elevations areas. This trend is expected to become more significant with intensifying climate warming, aligning with previous research [ 23 , 26 ]. The observed migration pattern may be related to changes in the species’ climatic niche.…”

“…Research conducted by Shao and Zhang on the Zelkova schneideriana communities in Jiangsu, China, demonstrated that Zelkova schneideriana is the most important dominant species, exhibiting limited competitive interactions with other tree species [ 22 ]. Building upon this, research conducted by Zhou et al revealed that the Zelkova schneideriana predominantly occurs in two forest ecosystems within China’s subtropical regions: deciduous broad-leaved forests and mixed bamboo and broad-leaved forests, covering 19 provinces nationwide [ 23 ]. However, excessive human logging and weak natural regeneration capacity have resulted in a continuous decrease in its distribution [ 24 , 25 ].…”

Predicting suitable habitat for the endangered tree Ormosia microphylla in China

“…The model predicts the species’ fundamental niche rather than the actual niche, resulting in the predicted potential distribution area being larger than the actual range. However, the species may fail to disperse to some suitable areas due to biogeographical barriers, such as human interference, topographical obstacles, and inter-specific competition 49 .…”