Repo for mesquite under various watering regime manuscript
We sought to identify the functional traits important for initial establishment of a globally invasive shrub, Prosopis spp., by quantifying morphological and ecophysiological responses of seedlings to contrasting moisture regimes. Our model plant was Prosopis velutina (Woot.), a prominent invader of North American grasslands. ## Methods Seedlings received one of three watering levels corresponding to regional ambient (100%), dry (-65%; reduction of 65% relative to ambient), and wet (+165%; increase of 65% relative to ambient) growing season precipitation regimes. A total of 32 plant aboveground, belowground, and ecophysiological traits were assessed when seedlings reached ages of 11- and 22-days. ## Results Germination under dry conditions was high (72%) and only slightly reduced compared to ambient and wet conditions with subsequent seedling survival unaffected. High trait plasticity supported early recruitment over the range of soil moisture conditions, including extreme drought. Fresh weight, absolute growth rate, tap root length, and root surface area and mass were the key traits in distinguishing between responses to altered moisture regimes. ## Conclusions Shrub seedling establishment in drylands characterized by low and variable rainfall is contingent on the ability to exploit short-term windows of soil moisture availability. Dry conditions reduced germination and slowed seedling growth but did not prevent early establishment. Our results do not support the widely held assumption that the initial recruitment of dryland shrubs is episodic with respect to above-average rainfall. Indeed, early recruitment of P. velutina and functionally similar species can potentially occur even in moisture conditions well below-average. Recognition of this potential should be factored into grassland conservation, management, and monitoring planning.
All scripts for analyses in the paper are in the Scripts directory. For details on a specific script and itβs purpose, see the Scripts/README.md.
Data for all analyses are in the Data directory.
Statistical outputs (descriptive stats, MANOVA, ANOVA, and post-hoc tests) are in the Outputs directory.