Climate biogeography ofArabidopsis thaliana:linking distribution models and individual variation

Abstract

AIM: The role of environmental conditions in limiting species distributions is often hypothesized, but it is challenging to gather large-scale data to demonstrate environmental impacts on individual performance. The past and present biogeography of model organisms is key context to understanding how environment shapes species' genetic and phenotypic diversity. LOCATION: Global. TAXON: Arabidopsis thaliana ("Arabidopsis"). METHODS: We fit occurrence records to climate data, and then projected the distribution of Arabidopsis under last glacial maximum, current, and future climates. We confronted model predictions with individual performance measured on 2,194 herbarium specimens, and we asked whether predicted suitability was associated with life-history variation measured on 898 natural accessions. RESULTS: The most important climate variables constraining the Arabidopsis distribution were winter cold in northern and high elevation regions and summer heat in southern regions. Herbarium specimens from regions with lower habitat suitability in both northern and southern regions were smaller, supporting the hypothesis that the distribution of Arabidopsis is constrained by climate-associated factors. Climate anomalies partly explained interannual variation in herbarium specimen size, but these did not closely correspond to local limiting factors identified in the distribution model. Late-flowering genotypes were absent from the lowest suitability regions, suggesting slower life histories are only viable closer to the center of the realized niche. We identified glacial refugia farther north than previously recognized, as well as refugia concordant with previous population genetic findings. Lower latitude populations, known to be genetically distinct, are most threatened by future climate change. The recently colonized range of Arabidopsis was well-predicted by our native-range model applied to certain regions but not others, suggesting it has colonized novel climates. MAIN CONCLUSIONS: Integration of distribution models with performance data from vast natural history collections is a route forward for testing hypotheses about species distributions and their relationship with evolutionary fitness across large scales.

Seasonal models reveal niche changes during invasion in Capsella bursa-pastoris

“…While the patterns of what environmental contributions contributed to each model are complex, there is a general trend that minimum temperature is more important in Europe while maximum temperature is more important in North America. A similar pattern is seen in Arabidopsis thaliana , a close relative of C. bursa-pastoris (Yim et. al., 2022).…”

Ecological trade-offs drive phenotypic and genetic differentiation of Arabidopsis thaliana in Europe

“…These variations are likely influenced by environmental factors associated with latitude, including temperature and day length. For example, populations at higher latitudes may exhibit delayed flowering to avoid late spring frost, while those at lower latitudes may have adaptations for coping with higher temperatures 44 . Here, we observed a center-to-margin trait differentiation rather than latitudinal clines, which was reflected in U-shape, or inverse U-shape, relationships between traits and latitude (Supplementary Fig.…”

“…The distribution and phenotypic diversity of cosmopolitan groups across Europe is constrained by climate-associated factors associated with latitude 44 . The most suitable habitats are found in central and western Europe.…”

Evaluating niche changes during invasion with seasonal models in Capsella bursa‐pastoris

“…A similar pattern where summer high temperature limits the non‐native North American range is also seen in Arabidopsis thaliana (L.) Heynh. [Brassicaceae], a close relative of C. bursa‐pastoris (Yim et al, 2022 [preprint]). Our findings also fit in with work from other systems showing that seasonal models have the potential to better describe key environmental features shaping occurrence (Batalden et al, 2007; Hereford et al, 2017; Williams et al, 2017; Ingenloff and Peterson, 2021).…”