Phenotypic distribution models corroborate species distribution models: A shift in the role and prevalence of a dominant prairie grass in response to climate change

Abstract

Phenotypic distribution within species can vary widely across environmental gradients but forecasts of species' responses to environmental change often assume species respond homogenously across their ranges. We compared predictions from species and phenotype distribution models under future climate scenarios for Andropogon gerardii, a widely distributed, dominant grass found throughout the central United States. Phenotype data on aboveground biomass, height, leaf width, and chlorophyll content were obtained from 33 populations spanning a ~1000 km gradient that encompassed the majority of the species' environmental range. Species and phenotype distribution models were trained using current climate conditions and projected to future climate scenarios. We used permutation procedures to infer the most important variable for each model. The species-level response to climate was most sensitive to maximum temperature of the hottest month, but phenotypic variables were most sensitive to mean annual precipitation. The phenotype distribution models predict that A. gerardii could be largely functionally eliminated from where this species currently dominates, with biomass and height declining by up to ~60% and leaf width by ~20%. By the 2070s, the core area of highest suitability for A. gerardii is projected to shift up to ~700 km northeastward. Further, short-statured phenotypes found in the present-day short grass prairies on the western periphery of the species' range will become favored in the current core ~800 km eastward of their current location. Combined, species and phenotype models predict this currently dominant prairie grass will decline in prevalence and stature. Thus, sourcing plant material for grassland restoration and forage should consider changes in the phenotype that will be favored under future climate conditions. Phenotype distribution models account for the role of intraspecific variation in determining responses to anticipated climate change and thereby complement predictions from species distributions models in guiding climate adaptation strategies.

Origins of abrupt change? Postfire subalpine conifer regeneration declines nonlinearly with warming and drying

“…, Smith et al. ). Seedlings generally produced more biomass and needles with warming, and root‐to‐shoot length ratios increased, with Douglas‐fir increasing more than lodgepole pine.…”

Intraspecific variation in lizard heat tolerance alters estimates of climate impact

“…This variation can dramatically modify inferences about behavioural patterns and fitness (Adolph & Porter, ) and, therefore, estimations of climate impacts accounting for trait (Cochrane, Yates, et al., ) or niche (Pearman, D'Amen, Graham, Thuiller, & Zimmermann, ) variation within species. For instance, phenotypic and species distributions can track different aspects of climate change (e.g., temperature vs. precipitation) and both complement impact assessments (Smith et al., ), climate effects can be masked by thermoregulation interacting with topography (Sears et al., ) and spatial scale (Barton, Clusella‐Trullas, & Terblanche, ), latitudinal enhancement of heat tolerance might signal recent poleward range expansions (Lancaster, ), while species distribution models can fail to detect constrains in population expansion (Kolbe et al., ) or area of occupancy (Benito Garzón et al., ) owing to trait plasticity. To illustrate this point, we predicted annual restriction times of 596, 668, 697 and 715 hr per 5 × 5 km 2 grid cell using the CT max of each of four populations of the Schreiber's green lizard L. schreiberi (CT max range = 40.5–42.9°C across individuals, and 41.0–42.1°C among population medians).…”

“…This variation can dramatically modify inferences about behavioural patterns and fitness (Adolph & Porter, 1993) and, therefore, estimations of climate impacts accounting for trait or niche (Pearman, D'Amen, Graham, Thuiller, & Zimmermann, 2010) variation within species. For instance, phenotypic and species distributions can track different aspects of climate change (e.g., temperature vs. precipitation) and both complement impact assessments (Smith et al, 2017), climate effects can be masked by thermoregulation interacting with topography (Sears et al, 2011) and spatial scale (Barton, Clusella-Trullas, & Terblanche, 2018), latitudinal enhancement of heat tolerance might signal recent poleward range expansions (Lancaster, 2016), while species distribution models can fail to detect constrains in population expansion (Kolbe et al, 2010) where it is mostly restricted to riparian shrubs in mountain ranges and low temperate forests close to mountain slopes (Monasterio, Shoo, Salvador, Iraeta, & Díaz, 2013). Our population-based modelling variation above would imply differences in predicted annual restriction times for the species from 85 to 102 seven-hour days per grid cell during which individuals would be forced to shelter from overheating.…”

“…Theoretical developments have demonstrated that incorporating intraspecific variability in lifehistory traits into modelling could substantially improve forecasts of how species ranges might respond to environmental shifts such as climate change (Ikeda et al, 2017;Valladares et al, 2014). This has been corroborated in a few applied studies, particularly with plants (Benito Garzón, Alía, Robson, & Zavala, 2011;Cochrane, Hoyle, Yates, Wood, & Nicotra, 2015;Smith, Alsdurf, Knapp, Baer, & Johnson, 2017), and including thermal traits in ectotherms such as insects (Lancaster, 2016), reptiles (Artacho, Saravia, Perret, Bartheld, & Le Galliard, 2017) and amphibians (Kolbe, Kearney, & Shine, 2010). However, little effort has been made to quantify the magnitude and the likely predictive importance of population differences in CT max for multiple species in a common biogeographical context.…”

Inference of biogeographic history by formally integrating distinct lines of evidence: genetic, environmental niche and fossil

“…nuclear microsatellites). Likewise, a better understanding of how functional traits relate to the environment (Kostikova et al 2013, Soudzilovskaia et al 2013, Smith et al 2017) coupled with growing databases on traits (Kattge et al 2011) could help constrain models of species' spread (Angert et al 2011). Additionally, microsatellites, large SNP datasets such as produced by RADseq, and sequences (from nuclear genomes and from chloroplasts) each offer different information content due to mutation and recombination, thus combining marker types should increase the ability of integrative modeling to make demographic inference, a point which to our knowledge is rarely exploited in the literature.…”