The potential effects of climate change on amphibian distribution, range fragmentation and turnover in China

Abstract

Many studies predict that climate change will cause species movement and turnover, but few have considered the effect of climate change on range fragmentation for current species and/or populations. We used MaxEnt to predict suitable habitat, fragmentation and turnover for 134 amphibian species in China under 40 future climate change scenarios spanning four pathways (RCP2.6, RCP4.5, RCP6 and RCP8.5) and two time periods (the 2050s and 2070s). Our results show that climate change may cause a major shift in spatial patterns of amphibian diversity. Amphibians in China would lose 20% of their original ranges on average; the distribution outside current ranges would increase by 15%. Suitable habitats for over 90% of species will be located in the north of their current range, for over 95% of species in higher altitudes (from currently 137-4,124 m to 286-4,396 m in the 2050s or 314-4,448 m in the 2070s), and for over 75% of species in the west of their current range. Also, our results predict two different general responses to the climate change: some species contract their ranges while moving westwards, southwards and to higher altitudes, while others expand their ranges. Finally, our analyses indicate that range dynamics and fragmentation are related, which means that the effects of climate change on Chinese amphibians might be two-folded.

Keywords: Amphibians; Climate impacts; Dispersal; Distribution; Fragmentation; MaxEnt; Range shifts; Turnover.

Figure 1. Predicted species movement in a climate scenario, using the BC45 scenario as an example.

The arrow represents the distance and direction of species geometric mean point at different periods. The black arrow presents climatic scenario of the 2050s, blue arrow presents climatic scenario of the 2050s–2070s. The wind roses summarize the distance and direction of shift for each species. The radiuses of rings on each wind rose represent geographical distance (inner circus: 2°; outer circus: 5°). The grey axis bars on wind roses represent a length of 7°. BC45 scenario represents BCC-CSM1-1 as AOGCM and using RCP4.5 as greenhouse gas scenarios. The figure was generated using R (http://www.R-project.org/), ggplot2 (https://cran.r-project.org/web/packages/ggplot2/index.html) and raster (http://CRAN.R-project.org/package=raster) softwares, and the map was created using data downloaded from the GADM database (http://www.gadm.org/) for free use.

Figure 2. Distribution patterns of 134 species of amphibians from different aspects.

Sub-graph (A) present latitude change of 134 kinds of amphibians. (B) present longitude change. (C) present altitude change. (D) present area change percent. (E) present distribution space loss percent. (F) new distribution space percent.

Figure 3. Percent of coherence index (CI) change.

CI is the probability that two animals placed in different areas (patches) will find each other. The order of 134 species in X axis from left to right depends on the order of mean value of area change (from low to high, to make thing to be comparable, the 2070s using the order of the 2050s). The dotted line means that the potential distribution area has no any change under future climatic change.

Figure 4. Turnover of species under climate change, using the BC45 scenario in the 2070s as example.

(A) species richness in current; (B) turnover rate; (C) turnover sum of 134 species. The figure was generated using R (http://www.R-project.org/), ggplot2 (https://cran.r-project.org/web/packages/ggplot2/index.html) and raster (http://CRAN.R-project.org/package=raster) softwares, and the map was created using data downloaded from the GADM database (http://www.gadm.org/) for free use. QL, Qinling Mountains; DB, Dabie Mountains; SC, Sichuan Basin and surrounding areas; GZ, western Guizhou province; WY, Wuyi Mountains; ZJJ, Zhangjiajie Nature Reserve; ZJH, Zhongjianhe Nature Reserve.