Annual variation in birds and plants of a tropical second-growth woodland
Looked at changes in plant and fruit eating bird diets in one secondary forest for three years (5, 6, 7, yr after abandonment). Vegetation changed from nearly impenetrable to rel more open. Decrease in canopy openenss and herbaceous shrubs. Plant resources directly used by birds (flowers, fruits) showed no significant changes overall among years in overall abundance. Second-growth bird and plant communities can be quite dynamic over relatively short times. Four of the eight common bird sp that showed little change in activity among years have lek breeding systems. Sp with specialized breeding systems may be more likely to remain in second-growth habitats over time, despite changes in veg structure and resource abundance. At the end of the study, the forest ws approximately 10 yers old and they saw evidence that birds typical of mature forest understory were colonizing. Thus, rapidly regenerating second-growth may be an improtant alternative habitat for some forest species. But although they may be benefcial for some species, seond-grwoth will not substitute for mature forest. Regenerating habitas often provide imprtant resources (fruit, nectar) for birds (and other animals) during periods of food shortage in more mature forests.