Treesearch

The Luquillo Experimental Forest (LEF) located on the Caribbean island of Puerto Rico has a rich history of ecological research, including a variety of avian studies, and is one of the most active ecological research sites in the Neotropics. The LEF spans an elevational range from 100 to 1075mover which five life zones and four forest types are found in a warm, humid subtropical climate. A total of 23 bird species breeds here and another 76 species, mostly migrants, are known to occur. The food web of the forest in the lower elevations is especially well studied, which allows an assessment...

We radiotracked Northern Waterthrushes (Parkesia noveboracensis) in four habitats in Puerto Rico during two winters (i.e., January–April) in 2003 and 2004 to determine the ecological determinants of diurnal space use and overwinter sitepersistence in this species. The majority of birds (69%) were sedentary and used a contiguous area within a single habitat over the winter period. A smaller percentage (31%) initially used a contiguous area within a single habitat but then permanently moved from that area to another disjunct location (mean = 418 m). Most of these movements were out of the...

We investigated the relationships among space-use patterns, home-range attributes, and individual characteristics to determine the consequences of different space-use strategies for the overwinter physical condition of Northern Waterthrushes (Parkesia noveboracensis). We have elsewhere demonstrated that heterogeneity in food availability drives the movement decisions of site-persistent and itinerant individuals during the nonbreeding period. Here, we show that intraspecific competition played an important role in determining where individuals initially and eventually settled. Territoriality...

Soils of tropical forests are important to the global budgets of greenhouse gases. The Brazilian Atlantic Forest is the second largest tropical moist forest area of South America, after the vast Amazonian domain. This study aimed to investigate the emissions of nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) fluxes along an altitudinal transect and the relation between these fluxes and other climatic, edaphic and biological variables (temperature, fine roots, litterfall, and soil moisture). Annual means of N2O flux were 3.9 (±0.4), 1.0 (±0.1), and 0.9 (±0.2) ngNcm−2 h−1 at...

Given that ecological effects of disturbance have been extensively studied in many ecosystems, it is surprising that few quantitative syntheses across diverse ecosystems have been conducted. Multi-system studies tend to be qualitative because they focus on disturbance types that are difficult to measure in an ecologically relevant way. In addition, synthesis of existing studies across systems or disturbance types is challenging because sufficient information needed for analysis is not easily available. Theoretical advances and improved predictions can be advanced by generalizations...

We analyzed how and why governmental forest regulation and nongovernmental forest certification in Costa Rica, Guatemala, and Nicaragua and their execution lead to, or fail to produce desired changes in forest owner and user behavior toward the enhanced sustainability of tropical forests. The findings confirmed not only that sufficient resources and capacity for forest policy execution are crucial for attaining policy objectives, but also that innovative arrangements for promoting, verifying, and enforcing policy compliance can compensate for limited resources and processes. Such arrangemen...

We report results of new research on (1) community composition of novel subtropical dry forests developing on abandoned pastures and agricultural fields in both private and protected public lands and (2) seed germination and growth rates of plantings of native tree species on degraded soils. We found that novel dry forests were dominated by introduced species, which accounted for 59 percent of the Importance Value (IV) of stands. These forests had high species dominance, with the most dominant species averaging 51 percent of the IV but reaching values as high as 92 percent. The floristic...

Seed dispersal by wind is a critical yet poorly understood process in tropical forest trees. How tree size and fecundity affect this process at the population level remains largely unknown because of insufficient replication across adults. We measured seed dispersal by the endangered neotropical timber species big-leaf mahogany (Swietenia macrophylla King, Meliaceae) in the Brazilian Amazon at 25 relatively isolated trees using multiple 1-m wide belt transects extended 100 m downwind. Tree diameter and fecundity correlated positively with increased seed shadow extent; but in combination...