EFFECT OF HERBIVORY ON THE REFORESTATION OF FOUR SPECIES OF THE FABACEAE FAMILY IN DETERIORATED AREAS

Abstract

Reforestation plays an important role in attempting to reverse ecosystem degradation in arid regions, where natural rainfall variability makes ecological restoration difficult. The aim of this work was to evaluate the survival and growth of four native species of the Fabaceae family (Prosopis velutina Wooton, Havardia mexicana (Rose) Britton & Rose, Parkinsonia microphylla Torr., and Olneya tesota A. Gray), with and without protection against herbivory in a degraded arid land in Sonora, Mexico. A three-level factorial design was established according to the protection treatments (PET and mesh, 20 and 30 cm in height, respectively) and a control (without protection). The variables of survival and height were evaluated 6, 12, and 24 months after transplant. Computer packages were used for the statistical analyses, establishing 5 % significance. Survival was highest in the plants with protection, with 100 % for the first year, both for PET and mesh, in comparison with a survival rate of 16.6 % for the unprotected control plants. The second year, the highest survival rate was found in plants protected by a mesh (41.6 %), whereas plants protected with PET and the control had the lowest survival rates, both with 8.3 % (χ2 = 5.674, p ≤ 0.058). The height of plants was affected by herbivory. Plants protected by mesh reached a greater height (29.4 cm) in comparison with the PET treatment, with 17.4 cm, and the control, with 3.1 cm (p < 0.0001). The growth of native forage fabaceae (leguminous) tree species in Sonora is extremely slow and relies on both herbivore protection and above-average rainfall years. This work presents the use of low-cost herbivory protection strategies to increase the survival and height of plants 2 years after being established.