The Potential Impacts of Climate Change on the Distribution of Tree Species

Editorial

15 November 2023

Editorial: The potential impacts of climate change on the distribution of tree species

Yanlong Guo

Chunyan Lu

Wei Gu

Zebin Zhao

and

Di Yang

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0 citations

Editors

YanLong Guo

Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS)

Chunyan Lu

Fujian Agriculture and Forestry University

Wei Gu

Shaanxi Normal University

Zebin Zhao

Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS)

Di Yang

University of Wyoming

Impact

Stomatal Conductance of Juveniles under Droughted and Ambient Treatments. The black dotted line shows the average time of permanent stomatal closure (n = 10 per species), when measurements were consistently at or below a minimum value of 90 mmol m−2 s−1 (solid gray horizonal line).

Original Research

12 October 2023

Mortality thresholds of juvenile trees to drought and heatwaves: implications for forest regeneration across a landscape gradient

Alexandra R. Lalor

, 6 more and

Greg A. Barron-Gafford

Tree loss is increasing rapidly due to drought- and heat-related mortality and intensifying fire activity. Consequently, the fate of many forests depends on the ability of juvenile trees to withstand heightened climate and disturbance anomalies. Extreme climatic events, such as droughts and heatwaves, are increasing in frequency and severity, and trees in mountainous regions must contend with these landscape-level climate episodes. Recent research focuses on how mortality of individual tree species may be driven by drought and heatwaves, but how juvenile mortality under these conditions would vary among species spanning an elevational gradient—given concurrent variation in climate, ecohydrology, and physiology–remains unclear. We address this knowledge gap by implementing a growth chamber study, imposing extreme drought with and without a compounding heatwave, for juveniles of five species that span a forested life zones in the Southwestern United States. Overall, the length of a progressive drought required to trigger mortality differed by up to 20 weeks among species. Inclusion of a heatwave hastened mean time to mortality for all species by about 1 week. Lower-elevation species that grow in warmer ambient conditions died earlier (Pinus ponderosa in 10 weeks, Pinus edulis in 14 weeks) than did higher-elevation species from cooler ambient conditions (Picea engelmannii and Pseudotsuga menziesii in 19 weeks, and Pinus flexilis in 30 weeks). When exposed to a heatwave in conjunction with drought, mortality advanced significantly only for species from cooler ambient conditions (Pinus flexilis: 2.7 weeks earlier; Pseudotsuga menziesii: 2.0 weeks earlier). Cooler ambient temperatures may have buffered against moisture loss during drought, resulting in longer survival of higher-elevation species despite expected drought tolerance of lower-elevation species due to tree physiology. Our study suggests that droughts will play a leading role in juvenile tree mortality and will most directly impact species at warmer climate thresholds, with heatwaves in tandem with drought potentially exacerbating mortality especially of high elevation species. These responses are relevant for assessing the potential success of both natural and managed reforestation, as differential juvenile survival following episodic extreme events will determine future landscape-scale vegetation trajectories under changing climate.

3,754 views

5 citations

Original Research

02 June 2023

Climate change effects on the potential distribution of the endemic Commiphora species (Burseraceae) on the island of Socotra

Dario La Montagna

, 6 more and

Michele De Sanctis

The Socotra Archipelago (Yemen) is an interesting biodiversity hotspot, with a significant proportion of endemic species that have evolved to survive in an arid subtropical environment, inscribed as a World Heritage Site by UNESCO. The terrestrial ecosystems of Socotra face several threats, including climate change, overgrazing and soil degradation. Socotra Island has four endemic species of the genus Commiphora (Burseraceae). Little is known about their local distribution and ecology, yet these trees could be useful indicator species. Our study focuses on the distribution and niche characterisation of the four endemic Commiphora species of Socotra and how climate change may affect them. The aim is to improve insights into their habitats and to provide an essential basis for future local management plans and ecological restoration. We compared the current distribution with the forecasted potential distribution under a CMIP6 (Coupled Model Intercomparison Project) climate scenario, allowing us to define target conservation areas and assess potential local extinction risks. To achieve this, we collected distribution data in the field throughout Socotra Island, covering the current distribution ranges of the four species. To assess the potential distribution of these species, we applied three models (GAM, MaxEnt, RandomForest) using bioclimatic, topographic and soil variables. Forecasts under a climate change scenario were made using bioclimatic variables from the CMCC-CESM2 climate model for two different socioeconomic pathways. The distribution of three endemic Socotran Commiphora is mainly correlated to clay content in the soil and winter precipitation, while C. socotrana is affected by seasonal precipitation and temperature. Under different potential future climate scenarios, the distribution of C. ornifolia is predicted to remain stable or increase, while C. parvifolia distribution could increase, yet C. planifrons and C. socotrana are predicted to undergo a strong reduction of suitable areas and an upward shift in the mountains. Our results highlight that it is essential to conserve the unique terrestrial ecosystems in Socotra and to preserve these endemic trees which have a wide range of ecosystem services. Updates on the predicted extinction risk assessment are fundamental to understand conservation priorities and strategize future actions to ensure the persistence of Socotran myrrh trees and other endangered endemic tree taxa on the island.

3,010 views

6 citations

Total vole mortality for both the 2021 and 2022 growing seasons, pooled among species for the north and south sides of the DWD. Y-axis represents total number of seedlings with dark gray representing vole mortality, lighter gray representing mortality from other causes, and lightest gray representing alive seedlings.

Original Research

02 October 2023

Experimental downed woody debris-created microsites enhance tree survival and growth in extreme summer heat

Mark E. Swanson

, 3 more and

Henry D. Adams

2,133 views

3 citations

Dynamics of mass loss of foliar litter at different elevations along Daiyun Mountain. Each bar represents the mean litter mass loss of different elevation (900–1,600 m) in that incubation site (N = 3). Sample size, N = 96, F-values from the effects of elevation, time and interactions of litter mass loss in a general linear mixed model (GLMM). Different lowercase letters indicate the difference among different elevations during the same decomposition period at a significance level of 0.05.

Original Research

15 May 2023

Microclimate along an elevational gradient controls foliar litter cellulose and lignin degradation in a subtropical forest

Bo Chen

, 8 more and

Zhongsheng He

1,494 views

4 citations

Changes in the net photosynthetic rate (A), stomatal conductance (B), and water use efficiency (C) under different salinity concentrations. Lowercase letters over the bars denote significance levels based on ANOVA post-hoc means using LSD analysis (p < 0.05).

Original Research

24 April 2023

Coordination in functional traits of Populus euphratica leaves under salt stress

Duan Li

, 2 more and

Jiyan Li

1,301 views

2 citations

Locations of 125 selected occurrence records (shown by white circles) of Mimosa bimucronata in China in relation to elevation. Images on the left show the species’ flowers, fruits and a small patch of the species.

Original Research

15 March 2023

Spatio-temporal patterns of an invasive species Mimosa bimucronata (DC.) Kuntze under different climate scenarios in China

Chunping Xie

, 2 more and

Dawei Liu

1,869 views

5 citations

Global distributions of the fundamental climate niche of lodgepole pine predicted by the final universal response function (fURF) for the current and the 2050s climates. The current fundamental climate niche distribution overlaid with the observed occurrence of lodgepole pine worldwide (A), where each dot represents a single occurrence point. Potential growth performances (represented by 20-year height) by the 2050s with emission scenario RCP 4.5 using climatically local (B), and optimal provenances (C). Differences in the performance between the two future projections (B,C) and the current are shown in panels (D,E), respectively.

Original Research

07 February 2023

Predicting the global fundamental climate niche of lodgepole pine for climate change adaptation

Yueru Zhao

and

Tongli Wang

The widely used species-occurrence-based models that predict the realized climate niche of plants can be too restrictive and do not reflect among-population variation in assessing climate change impact and guiding assisted migration for adaptation to future climates. To mitigate this deficiency, this study built a fundamental climate niche model for lodgepole pine (Pinus contorta Dougl. ex Loud.) based on 20-year tree height from wide-ranging provenance trials as a case study. The model was built through comparisons and optimizations of two candidate models, universal response function (URF) and universal transfer function (UTF), with linear and linear mixed-effect forms, against varying sample sizes based on the comprehensive provenance trials. We found that URF and UTF models had similar performances, while URF models were more straightforward in identifying optimal provenances for planting sites. Linear mixed-effect models did not show clear advantages over linear models in our case but prevented including additional predictors, which are often critical. We selected the linear model of URF and predicted the fundamental climate niche of lodgepole pine on a global scale and revealed a great potential of using this species for climate change adaptation beyond its native distribution, representing a significant step in forest genecology. Our study presented a new approach for assisted migration at the species and the population levels to optimize adaptation and productivity under a changing climate.

1,965 views

8 citations

Original Research

11 January 2023

Modeling habitat suitability of Hippophae rhamnoides L. using MaxEnt under climate change in China: A case study of H. r. sinensis and H. r. turkestanica

Xiao-hui He

, 7 more and

Xing-lin Zhu

Hippophae rhamnoides is widely known for its important ecological, economic, and social benefits. It is known as the pioneer plant of soil and water conservation, with homology in food and medicine. With the climate warming in recent years, the numbers of this species and countries with this plant have decreased steadily. H. r. sinensis and H. r. turkestanica have the widest distribution area in China, which account for more than 90% of the total national Hippophae rhamnoides resources. We firstly screened the presence data and downscale the environment variables (climate and soil) by correlation analysis. Secondly, based on the 232 occurrence data of H. r. sinensis and 10 environmental variables, the 73 occurrence data of H. r. turkestanica and 11 environmental variables, we simulated and predicted their suitable habitats in China, both at the current time and in the 2050S (2041–2060), and analyzed the dominant factors effecting its distribution by using MaxEnt. Finally, we studied the habitat variations and centroid migrations of these subspecies under future climate scenarios using the spatial analysis function of ArcGIS. The results indicated that the area of suitable habitat for H. r. sinensis is much larger than that of H. r. trkestanica in China. The suitable habitat of H. r. sinensis is concentrated in the middle and upper reaches of the Yellow River, mainly distributed in Shaanxi, Shanxi, Sichuan, Qinghai, Gansu, Ningxia, Tibet, and Inner Mongolia, and that of H. r. trkestanica is mainly distributed in Xinjiang and Tibet. The former is mainly affected by bio13 (precipitation of the wettest month), bio11 (mean temperature of the coldest quarte) and bio3 (Isothermality), and the latter is mainly affected by bio13 (precipitation of the wettest month), bio2 (mean diurnal range) and bio15 (precipitation seasonality), and the former is also more stable in the face of future climate change. They are more susceptible to climate than soil in their survival. Although, the two subspecies tend to expand and migrate toward lower latitude under future climate scenarios, there are some differences. H. r. sinensis will migrate westward, while H. r. trkestanica will migrate eastward as a whole. They have a high stability of suitable habitat and are not at risk of extinction in the future. The study’s findings help to clarify the resource reserve of Hippophae rhamnoides L. in China, which will help to guide the protection of wild resources and to popularize artificial planting in suitable areas, and provides scientific basis for the protection of ecological environment.