Regional disparity in extinction risk: Comparison of disjunct plant genera between eastern Asia and eastern North America

Effects of ultraviolet radiation as a climate variable on the geographic distribution of Oryza sativa under climate change based on Biomod2

Introduction

Oryza sativa is one of the most important cereal crops globally.

Methods

The aim of this study was to map areas suitable for the growth and conservation of O. sativa under current and future climatic conditions, and to observe the effects of UV variables on the distribution area of O. sativa.

Results

Based on species distribution records, we used the Biomod2 platform to combine climate data, future shared socioeconomic pathways, and elevation data. The ensemble model (EM) was constructed by screening multiple species distribution models (SDMs), including RF, GBM, ANN, and MARS. The ROC value of the joint model is greater than 0.95, indicating that the model has high reliability and accuracy. Mean annual temperature (bio01), temperature seasonality (bio04), minimum temperature in the coldest month (bio06), mean temperature of coldest quarter (bio11), human footprint and human activity impact index (hfv2geo1) and annual average ultraviolet radiation (uvb1annualmeanuv.b) were the most important environmental variables affecting the suitable distribution area of O. sativa. Under the current climate conditions, the suitable habitats of O. sativa are mainly distributed in the south of the Yangtze River. In the future climate scenario, the total suitable habitat area of O. sativa tended to decrease, but the suitable distribution area under the influence of UV was larger than that without UV.

Discussion

Climate change will significantly affect the potential distribution of O. sativa in China and increase its extinction risk. Therefore, it is necessary to provide a reference for the conservation, management, introduction and cultivation of food crops in China.

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

This study utilized the platform for ensemble forecasting of species distributions, biomod2, to predict and quantitatively analyze the distribution changes of Zelkova schneideriana Hand.-Mazz. under different climate scenarios (SSP1-2.6 and SSP5-8.5) based on climate and land-use data. This study evaluated the geographic range changes in future distribution areas and the results indicated that, under both SSP1-2.6 and SSP5-8.5 scenarios, the distribution area of Zelkova schneideriana would be reduced, showing a trend towards migration to higher latitudes and elevations. Particularly, in the more extreme SSP5-8.5 scenario, the contraction of the distribution area was more pronounced, accompanied by more significant migration characteristics. Furthermore, the ecological structure within the distribution area of Zelkova schneideriana also experienced significant changes, with an increasing degree of fragmentation. The variables of Bio6 (minimum temperature of the coldest month), Bio2 (mean diurnal temperature range), Bio15 (precipitation seasonality), and elevation exhibited important influences on the distribution of Zelkova schneideriana, with temperature being particularly significant. Changes in land use, especially the conversion of cropland, had a significant impact on the species' habitat. These research findings highlight the distributional pressures faced by Zelkova schneideriana in the future, emphasizing the crucial need for targeted conservation measures to protect this species and similar organisms.

Soil properties constrain predicted poleward migration of plants under climate change

Many plant species are predicted to migrate poleward in response to climate change. Species distribution models (SDMs) have been widely used to quantify future suitable habitats, but they often neglect soil properties, despite the importance of soil for plant fitness. As soil properties often change along latitudinal gradients, higher-latitude soils might be more or less suitable than average conditions within the current ranges of species, thereby accelerating or slowing potential poleward migration. In this study, we built three SDMs - one with only climate predictors, one with only soil predictors, and one with both - for each of 1870 plant species in Eastern North America, in order to investigate the relative importance of soil properties in determining plant distributions and poleward shifts under climate change. While climate variables were the most important predictors, soil properties also had a substantial influence on continental-scale plant distributions. Under future climate scenarios, models including soil predicted much smaller northward shifts in distributions than climate-only models (c. 40% reduction). Our findings strongly suggest that high-latitude soils are likely to impede ongoing plant migration, and they highlight the necessity of incorporating soil properties into models and predictions for plant distributions and migration under environmental change.