Optimizing Species Selection for Forest Restoration in the Lower Rio Grande Valley

Over the past four decades, the Lower Rio Grande Valley has been reforested with over 3.3 million native thornscrub plants in old agricultural land through transplanting native species. However, assessments of LRGV forest restoration efforts are scarce, and to address the knowledge gap, this study examined species-specific responses to restoration interventions (RIs) aimed at minimizing seedling mortality for optimizing species selection. A critical period for forest restoration in old croplands is the seedling stage, where high mortality occurs due to the interactive effects of abiotic stress, compromised soil nutrient status from intensive agriculture, and mammalian herbivory. So, we evaluated seedling mortality and growth in 24 native species in response to physical seedling shelters and mycorrhiza-biostimulants admixture. We also quantified 15 plant functional traits including, wood density, root mass fraction, stem height, root tips, leaf tissue density to determine the potential of these plant traits to serve as predictors of native plant mortality in restoration by associating them with species-specific differential mortality data obtained in the field. We found that only physical shelters reduced overall mortality and greater wood density, root mass fraction and lower root tips, stem height were associated with lower seedling mortality. These results contribute to an integrative understanding of the physiology of native plants and extend the scope of this work to aid in the selection of species and interventions in forest restoration