Treesearch

El mapa de unidades del paisaje de Puerto Rico representa variaciones climaticas, topograficas y del substrato mediante la integracion de seis zonas climaticas (Ewel y Whitmore, 1973), seis substratos (Bawiec, 2001; USGS, 2005), cinco posiciones topograficas, o topoformas (Martinuzzi et al. 2007), y cuerpos de agua (USGS 2005). Los substratos representan el conjunto simplificado creado por Bawiec (2001) compuesto por doce unidades de terrenos geologicos. Estos terrenos estan clasificados en : depositos de roca caliza del cretaceo y terciario, depositos de aluvion y otros depositos no...

El Proyecto de Analisis de Gap de Puerto Rico (PRGAP) (Gould et al. 2008) desarrollo tres usos de terrenos para Puerto Rico: Urbano, Suburbano, y Rural (Martinuzzi et al. 2007). Estas regiones tambien pueden ser consideradas como urbano, densamente-poblado rural, y escasamente-poblado rural, o como urbano y area silvestre con una interfase de area silvestre-urbana. La categoria de suburbano es la más dinamica en terminos de crecimiento poblacional y cambio en la cobertura del terreno. La superficie desarrollada se refiere aqui a areas urbanas, construidas y sin vegetacion, que resultan de...

Arctic landscapes have visually striking patterns of small polygons, circles, and hummocks. The linkages between the geophysical and biological components of these systems and their responses to climate changes are not well understood. The “Biocomplexity of Patterned Ground Ecosystems” project examined patterned-ground features (PGFs) in all five Arctic bioclimate subzones along an 1800-km trans-Arctic temperature gradient in northern Alaska and northwestern Canada. This paper provides an overview of the transect to illustrate the trends in climate, PGFs, vegetation, n-factors, soils,...

Decomposition is a critical ecosystem function that decomposes dead organic materials, removes wastes, recycles nutrients and renews soils fertility. In natural ecosystems most nitrogen (N) and phosphorus (P) required for plant growth are supplied through the decomposition of detritus, relying therefore on the activities of soil microbes and microfauna. Decomposition is a consequence of interacting physical and chemical processes occurring inside and outside of living organisms in an ecosystem (Chapin III et al. 2002). The two major processes include fragmentation, breaking larger pieces...

Earthworms are classified into endogeic, anecic, and epigeic species to represent soil, soil and litter, and litter feeders, respectively (Bouché 1977). Earthworms can alter soil physical properties and biogeochemical processes (e.g., Ewards and Bohlen 1996) according to their functionality. Endogeic earthworms alter soil properties primarily through changing soil physical and chemical properties and epigeic earthworms mainly affect microbial inoculation and the associated decomposition processes. Anecic earthworm influence soils through both borrowing and inoculation activities (González...

The relative importance of genetic, demographic, environmental, and catastrophic processes that maintain population bottlenecks has received little consideration. We evaluate the role of these factors in maintaining the Puerto Rican Parrot (Amazona vittata) in a prolonged bottleneck from 1973 through 2000 despite intensive conservation efforts. We first conduct a risk analysis, then examine evidence for the importance of specific processes maintaining the bottleneck using the multiple competing hypotheses approach, and finally integrate these results through a sensitivity analysis of a...

Satellite image-based mapping of tropical forests is vital to conservation planning. Standard methods for automated image classification, however, limit classification detail in complex tropical landscapes. In this study, we test an approach to Landsat image interpretation on four islands of the Lesser Antilles, including Grenada and St. Kitts, Nevis and St. Eustatius, testing a more detailed classification than earlier work in the latter three islands. Secondly, we estimate the extents of land cover and protected forest by formation for five islands and ask how land cover has changed over...

We dug a soil pit of 1m x 1m x 1m in a forest dominated by Castilla elastica, a tree for shade coffee introduced in the karst of northern Puerto Rico. We found four soil horizons (designation notes in parenthesis) (A) organic soil matter (E) mineral soil leachate (B) aerobic mineral soil, and (C) saturated soil. The total storage of soil organic matter was 143 Mg/ha. Apparent soil density increased with depth, the ground-water level was between 65 and 80 cm deep, and there were no roots >55 cm deep. This suggests that most of the C. elastica roots are superficial and unlikely to tolerate...