Grow Where You Thrive, or Where Only You Can Survive? An Analysis of Performance Curve Evolution in a Clade with Diverse Habitat Affinities

AbstractPerformance curves are valuable tools for quantifying the fundamental niches of organisms and testing hypotheses about evolution, life-history trade-offs, and the drivers of variation in species’ distributionpatterns. Here, we present a novel Bayesian method for characterizing performance curves that facilitates comparisons among species. We then use this model to quantify and compare the hydrologicalperformance curves of 14 different taxa in the genus Lasthenia, an ecologically diverse clade of plants that collectively occupy a variety of habitats with unique hydrologicalfeatures, including seasonally flooded wetlands called vernal pools. We conducted a growth chamber experiment to measure each taxon’s fitness across five hydrologicaltreatments that ranged from severe drought to extended flooding, and we identified differences in hydrologicalperformance curves that explain their associations with vernal pooland terrestrial habitats. Our analysis revealed that the distribution of vernal pool...