Effects of Scarification, Phytohormones, Soil Type, and Warming on the Germination and/or Seedling Performance of Three Tamaulipan Thornscrub Forest Species.

Paula Luera,Kimberly Wahl-Villarreal,Christopher A Gabler,Abeny Treviño,Pushpa Soti,Bradley O Christoffersen

doi:10.3390/plants10081489

Paula Luera, Kimberly Wahl-Villarreal + Show 4 more

Open Access

https://doi.org/10.3390/plants10081489

Copy DOI

Abstract

The Tamaulipan thornforests of south Texas and northeast Mexico are an ecologically and economically important conservation hotspot. Thornforest restoration is limited by native tree and shrub seedling availability for planting. Seedling shortages arise from low seed availability and knowledge gaps regarding best practices for germinating and growing the 70+ thornforest species desired for restoration plantings. To fill key knowledge gaps, we investigated three ecologically important thornforest species with low or highly variable germination or seedling survival rates: Ebenopsis ebano, Cordia boissieri, and Zanthoxylum fagara. For each, we quantified the effects of different dosages of chemical seed treatments used to promote germination (sulfuric acid, SA; gibberellic acid, GA; indole-3-butyric acid, IBA) on germination likelihood and timing. We also quantified the effects that these chemical seed treatments, soil media mixture type, and soil warming had on seedling survival, growth, and root morphology. Ebenopsis germination peaked (>90%) with 40–60 min SA treatment. Cordia germination peaked (40%) with 100 mg/L GA treatment. Zanthoxylum germination was negligible across all treatments. Seed molding was rare but stirring during SA treatment reduced Ebenopsis molding by 4%. Ebenopsis seedling survival, height, leaf count, and root morphology were minimally affected by seed treatments, generally reduced by warming, and influenced by soil mix, which also mediated responses to warming. These results suggest improvements to existing practices that could increase Ebenopsis germination by 10–20% and potentially double Cordia germination.

Highlights

Deforestation is both a driver and consequence of climate change, while reforestation offers a means to mitigate climate change
This study focuses on three woody plant species native to Tamaulipan thornscrub forests: Ebenopsis ebano (Berl.) Barneby and Grimes, Cordia boissieri A
Sulfuric acid (SA) treatment: Soaking time in sulfuric acid had a significant effect on the likelihood of germination in both the unstirred (ANODEV, χ2 = 150.33, p < 0.0001) and stirred (ANODEV, χ2 = 80.81, p < 0.0001) treatments (Figure 1a,b)

Summary

Introduction

Deforestation is both a driver and consequence of climate change, while reforestation offers a means to mitigate climate change. To reverse habitat loss and mitigate climate change while supporting human populations, many land management techniques aim to conserve or restore habitats that provide multiple important ecological functions, such as wildlife habitat or carbon sequestration [7,8], and often promote forest conservation and restoration in urban and rural sites [9,10]. Principal among these functions are wildlife habitat, which supports a hundredmillion-dollar regional ecotourism industry based largely around bird- and butterflywatching, and carbon sequestration [11,12,13] These dense and well-armed forests provide a short, thick canopy preferred by many native reptiles and mammals, including endangered ocelots (Leopardus pardalis) that depend on closed-canopy thornforests with >95%

Methods

Results

Discussion

Conclusion