Avian use of an exotic tree (Gmelina arborea) plantation in Guatemala: Evaluating its conservation potential as an alternative land-use

Hierarchical approaches to the study of ecological patterns and processes are an effective means for evaluating environmental problems for conservation. One such problem is the continued anthropogenic change to natural landscapes over large spatial scales in the tropics, and the influence of this change on species that occupied those lands. Further compounding the problem is the realization that parks and reserves set aside to preserve affected species may not have the capacity to maintain long-term biologic diversity, and land-uses that have replaced these natural areas cannot support the same species-rich communities. I evaluated one of these new land-uses, a 7000 hectare Gmelina arborea tree plantation in Guatemala, to assess its potential role in bird conservation and its suitability as habitat for forest bird species. I examined local and landscape-scale vegetation patterns along with individual bird species distribution to see if scale-dependent vegetation attributes and bird species making up the avian community were significantly associated with one another. In addition, I examined foraging behavior and its relation to food availability of a subset of species.; The plantation was forest-like in structure, and supported mostly habitat generalists and edge-tolerant forest bird species, of which 28% were Neotropical migrants. I found a statistically significant positive relationship between increasing local-scale vegetative complexity and bird species richness and species composition, along with a strong significant association between landscape-scale forest coverage and individual bird species distribution patterns and the communities they compose. Sixty-four percent of the bird species I examined were significantly associated with landscape-scale predictors. Several bird species significantly preferred G. arborea over native trees as a foraging site, and several species were observed to exhibit behavioral plasticity in response to the non-native trees. Overall, I found that vegetatively complex areas within the heterogeneous Gmelina plantation had the ability to support bird communities similar to edge and secondary growth habitats in the region, as well as to maintain species richness similar to that of some shaded coffee plantations. These data indicate that, if managed with natural vegetation, G. arborea plantations may be an alternative to degraded pastureland in the Neotropics.