干旱区生态环境知识资源中心

The tropical dry deciduous forest (TDF) of the semi-arid region of Bajio in Mexico is dominated by successional communities, in which Lysiloma microphyllum is irregularly distributed, however the environmental factors influencing its establishment have been poorly studied. We conducted field experiments to isolate the impact of three factors on the early life-history stages of this tree. Over a 2-y period, we monitored the effects of (1) predation, (2) understorey light and (3) aspect on germination, seed-to-seedling transition (establishment) and seedling survival, and we found that open space negatively affected germination (14.9 +/- 1.5% vs 96 +/- 1.5% in shade; mean +/- SE), while shade increased seedling establishment and survival (36.9 +/- 8.2% vs 4.7 +/- 3.8% in open sites). Predation decreased survival and was strongest in open conditions (0 vs 62.7 +/- 9.4% in shaded exclosures). In contrast, aspect had little influence on germination and survival. The results suggest that shaded microsites positively affect the early life stages of L. microphyllum, a key process in TDF recovery.