Predicting Future Seed Sourcing of Platycladus orientalis (L.) for Future Climates Using Climate Niche Models

Abstract

Climate niche modeling has been widely used to assess the impact of climate change on forest trees at the species level. However, geographically divergent tree populations are expected to respond differently to climate change. Considering intraspecific local adaptation in modeling species responses to climate change will thus improve the credibility and usefulness of climate niche models, particularly for genetic resources management. In this study, we used five Platycladus orientalis (L.) seed zones (Northwestern; Northern; Central; Southern; and Subtropical) covering the entire species range in China. A climate niche model was developed and used to project the suitable climatic conditions for each of the five seed zones for current and various future climate scenarios (Representative Concentration Pathways: RCP2.6, RCP4.5, RCP6.0, and RCP8.5). Our results indicated that the Subtropical seed zone would show consistent reduction for all climate change scenarios. The remaining seed zones, however, would experience various degrees of expansion in suitable habitat relative to their current geographic distributions. Most of the seed zones would gain suitable habitats at their northern distribution margins and higher latitudes. Thus, we recommend adjusting the current forest management strategies to mitigate the negative impacts of climate change.

Incorporating local adaptation into forecasts of species’ distribution and abundance under climate change

“…Very few of the SDM studies we reviewed looked for evidence of adaptation to local climate in the different intraspecific groups. However, a recent trend in SDM papers is to also use occurrence and climate data to test for similarity in the climatic niches of the groups (e.g., Hu et al, ; Ikeda et al, , Meynard et al, ). An important caveat is that patterns of occurrence by themselves do not provide very strong tests of the hypothesis that intraspecific groups differ in their environmental tolerances.…”

“…None of the studies we reviewed included climate responses across the entire life cycle of an organism or allowed climate tolerances to continue to evolve over time (Appendix S2). Only three studies considered LA to aspects of the local environment other than climate (Hu et al, ; Schwalm et al, ; Wang et al, ), and none considered LA to biotic drivers such as interacting species. Only two studies included empirical estimates of dispersal rates (Cacciapaglia & van Woesik, ; Morin et al, ) and none considered gene flow among intraspecific lineages or locations.…”

“…Other advantages of SDMs are that they commonly consider an extensive set of potential climate variables (Supporting Information Appendix S2), increasingly incorporate model uncertainty by using several algorithms, and build uncertainty in future climate into ensemble-based distribution forecasts (Table 1; Araújo & New, 2007;Thuiller, 2004 Very few of the SDM studies we reviewed looked for evidence of adaptation to local climate in the different intraspecific groups. However, a recent trend in SDM papers is to also use occurrence and climate data to test for similarity in the climatic niches of the groups (e.g., Hu et al, 2017;Ikeda et al, 2017, Meynard et al, 2017. An important caveat is that patterns of occurrence by themselves do not provide very strong tests of the hypothesis that intraspecific groups differ in their environmental tolerances.…”

“…SDMs were the only models to incorporate uncertainty in future climate conditions when making forecasts, and were also more likely to compare intraspecific models to forecasts from a species-wide model ( Table 1, Supporting Information Appendix S2), even though it would be straightforward to do both using other approaches. However, most models, especially SDMs, were cross-validated to a portion of the dataset (Figure 2d) Only three studies considered LA to aspects of the local environment other than climate (Hu et al, 2017;Schwalm et al, 2016;Wang et al, 2010), and none considered LA to biotic drivers such as interacting species. Only two studies included empirical estimates of dispersal rates (Cacciapaglia & van Woesik, 2018;Morin et al, 2008) and none considered gene flow among intraspecific lineages or locations.…”

Local Adaptation and Response of Platycladus orientalis (L.) Franco Populations to Climate Change

“…Therefore, assessment of the potential growth response of forest trees to climate change and the selection of optimal provenances are critical to improving the survival rate of tree populations facing climate change [13]. Since the species distribution model (SDM) was first used to explore the distributional limits of plant species in 1980s [14,15], it has been widely used to predict potential changes in species distributions under climate change scenarios [16][17][18][19]. However, SDMs treat tree species as single homogeneous entities and cannot predict growth rates; thus, among-population variation within tree species could not be considered in developing forest adaptive strategies through seed transfer and assisted migration.…”