Demographic effects of legal timber harvesting on Guaiacum sanctum L., an endangered neotropical tree: implications for conservation

Abstract

Guaiacum sanctum is a timber tree species from the Americas, considered threatened in eleven different countries, including Mexico, and listed in CITES Appendix II. This species is currently harvested legally in the southern Mexican state of Campeche. Despite its protected status, the current condition of its populations and the effects of harvesting upon them have not been assessed. The conservation status of four unlogged populations were evaluated across Central Campeche by documenting their densities and demographic structures, and then compared the size class demographic structures of one unlogged and three logged populations at different times after harvest (3, 8 and 20 years) to evaluate the effects of timber harvesting upon population structure. Additionally, a regeneration index (proportion of seedlings within the population) was estimated for each of the seven populations. Densities of G. sanctum varied from 278 to 1732 stems/ha with ≥1cm at 1.3m·height in Campeche. Differences were found in the population structures of unlogged populations, although the density of seedlings and trees was high in all of the sites. Contrary to expectations, higher densities were found in all size classes in logged populations. Results suggest that current logging practices do not have a drastic negative effect on the density of remaining individuals. Although the results indicate that G. sanctum in Campeche is not locally endangered, it is recommend that it be maintained in CITES Appendix II.