Abstract:
Most reserves fail to capture the habitat heterogeneity necessary to maintain viable
populations of wide-ranging species. Methods to determine defensible dimensions of
reserves and reserve networks are needed. The primary goal of this study was to develop
such methods for lowland tropical forests by examining habitat- and spatial-use patterns of the
Mealy Parrot (Amazona farinosa) in northern Guatemala. Regional connectivity has been
demonstrated by altitudinal migration of birds that track seasonal fruit availability; it is now
recognized that a suite of habitats along the elevational gradient must be protected to
conserve biodiversity of tropical montane ecosystems. However, in tropical lowlands, little is
known about spatiotemporal patterns of resources and animals that rely on them. I
considered the large-bodied, frugivorous Mealy Parrot a useful focal species because its
movements and habitat use should be coupled with the ecological factors determining fruit
distribution. Individual- and population-based methods were developed in this study. In each
of 4 years, radio telemetry revealed that adult Mealy Parrots breeding in northeastern
Guatemala engaged in predictable seasonal migrations within mature lowland forest.
Although the area covered by these parrots was considerable (10,000 km²), more significant
was the consistency of their movements and specific locations utilized. Canopy-based
population surveys were used to estimate densities of all 6 locally occurring parrot species as
a function of landscape type and season over a two-year period; the data suggest that
migration is common in this parrot community. Mealy Parrots rely on mature lowland forest
arrayed along regional environmental gradients. Over distances of a few hundred kilometers
and a range in elevation of [approximately] 200 m, variation in fruiting phenology, forest composition, and
rainfall shape this species' movement patterns. Basing reserve design on size alone is
insufficient. Large protected areas, such as the 600 km² Tikal National Park and even the
21,000 km² Maya Biosphere Reserve, will not maintain this population of Mealy Parrots
without inclusion of areas that encompass the range of spatiotemporal variability governing
migration patterns. The Mealy Parrot occurs from Mexico through Amazonia and may serve
as a valuable focal species for conservation planning in other parts of its range.
