Treesearch

Throughout the tropics, population movements, urban growth, and industrialization are causing conditions that result in elevated temperatures within urban areas when compared with that in surrounding rural areas, a phenomenon known as the urban heat island (UHI). One such example is the city of San Juan, Puerto Rico. Our objective in this study was to quantify the UHI created by the San Juan Metropolitan Area over space and time using temperature data collected by mobile- and fixed-station measurements. We also used the fixed-station measurements to examine the relationship between average...

Tree cover and species composition were surveyed in 1998, 2003, and 2010 after the elimination of grazing and fire on the lower 32 hectares of the Tinaja tract at Laguna Cartagena National Wildlife Refuge in south-western Puerto Rico. Surveys of the secondary subtropical dry forest showed that stems increased 3.9 times, trees 6.7 times, basal area 3.3 times, and biomass 4.4 times between 1998 and 2010. Notable differences occurred by site. Greater numbers of stems and trees, greater basal areas, and usually biomass were tallied on 10 plots along the southern boundary closer to residual...

Photographic key to determine age in two Thryothorus wrens from Nicaragua's Pacific slope. – We used plumage and molt characteristics to determine age in two Neotropical species of the family Troglodytidae, Rufous-and-White Wren (Thryothorus rufalbus) and Plain Wren (T. modestus). Color density, shape, and strength of the black barring in the remiges, rectrices, and greater coverts are more prominent in UCB and DCB birds than in FCJ and FCF individuals. We used wing length in combination with plumage characters and brood patch to determine the sex of Thryothorus rufalbus and caution...

Many serious ecosystem consequences of climate change will take decades or even centuries to emerge. Long-term ecological responses to global change are strongly regulated by slow processes, such as changes in species composition, carbon dynamics in soil and by long-lived plants, and accumulation of nutrient capitals. Understanding and predicting these processes require experiments on decadal time scales. But decadal experiments by themselves may not be adequate becausemany of the slowprocesses have characteristic time scales much longer than experiments can bemaintained. This article...

We used radiotelemetry to quantify habitat and spatial use patterns of neighboring Louisiana Waterthrush (Parkesia motacilla) along two streams in the Caribbean National Forest in Puerto Rico during 2005–2007. Home range sizes varied with younger birds having larger home ranges and core areas than older birds. All birds occupied some length of stream but a wide range of off-stream habitats were also used. Off-stream habitats included a range of disturbance from residential areas to small saturated pastures. Neighbors exhibited a wide range of overlap in home ranges (x¯ 5 20%) and older...

The African tulip tree, Spathodea campanulata, dominates many post-agricultural secondary forests in the moist tropics. Some consider these novel forests have no ecological value, yet they appear to restore ecosystem processes on degraded sites. This study describes the litterfall mass and seasonality, canopy phenology, and microclimate of S. campanulata forests on alluvial and karst substrates in northern Puerto Rico. These substrates have different water drainage properties and I hypothesized that (1) annual leaf fall mass and seasonality would differ between substrate types; because (2)...