Changes in vegetation structure and composition along a tropical forest chronosequence: implications for wildlife Saara J. DeWalt a,* , Satya K. Maliakal a , Julie S. Denslow a,b a Department of Biological Sciences, 107 Life Sciences Building, Louisiana State University, Baton Rouge, LA 70803, USA b USDA Forest Service, Institute of Pacific Islands Forestry, 23 E. Kawili St., Hilo, HI 96720, USA Received 28 September 2002; received in revised form 25 October 2002; accepted 30 December 2002 Abstract Changes in tropical forest structure and species composition that occur during regeneration following land abandonment may have important consequences for wildlife populations. Many animals rely on forest resources as sites for foraging, nesting, and protection that may vary in abundance in forests of different ages. In this study, we examined aspects of forest composition and structure thought to be important to wildlife along a tropical moist forest chronosequence in the Barro Colorado Nature Monument (BCNM) of central Panama. Secondary forests of approximately 20, 40, 70, and 100 years in fallow as well as two stands of old-growth forest (>500 years) were intensively studied. All stands were located on relatively fertile soils and were in close proximity to old-growth forest. Within 70 years following cessation of active management, many structural aspects of secondary forests resembled those of old-growth stands. Large living tree (65 cm diameter) density and coarse-woody debris volume increased with secondary forest age and were equivalent to old-growth levels by 70 years. Snag density and basal area did not differ with stand age. Species composition and availability of food resources in secondary forests did not converge on old-growth characteristics as quickly as most structural aspects, but many resources available to generalist frugivores were common across the chronosequence. Tree, but not liana, species composition of secondary stands became more similar to old growth with increasing forest age. Understory fleshy fruit availability was highest in young secondary stands, while importance values of trees and lianas with animal-dispersed fruits remained unchanged across the chronosequence. The importance of species particularly important to some frugivores, such as Ficus and Virola, had unpredictable distributions, but palm importance value increased with stand age. We suggest that young secondary forests may provide adequate nesting, foraging, and roosting resources for many animal taxa, but some populations of animals specializing on coarse-woody debris, large trees, or particular species of trees may be limited in secondary forest less than 70 years old. # 2003 Elsevier Science B.V. All rights reserved. Keywords: Coarse-woody debris; Forest structure; Neotropics; Snags; Succession 1. Introduction Old-growth tropical forests are high priorities for conservation because of their complex structure and high tree and animal species diversity. However, the conservation value of secondary tropical forests also becomes important as old-growth tropical forests are logged or cleared. Without further anthropogenic disturbance, natural successional processes eventually may restore attributes of old-growth forests to these degraded ecosystems. Although the relative roles of vegetation structure and composition in structuring Forest Ecology and Management 182 (2003) 139–151 * Corresponding author. Present address: 5518 Covode St. #A2, Pittsburgh, PA 15217-1950, USA. Tel.: þ1-412-421-3495. E-mail address: sdewalt@lsu.edu (S.J. DeWalt). 0378-1127/$ – see front matter # 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0378-1127(03)00029-X