Treesearch

This letter reports the sensitivity of X-band interferometric synthetic aperture radar (InSAR) data from the first dual-spacecraft radar interferometer, TanDEM-X, to variations in tropical-forest aboveground biomass (AGB). It also reports the first tropical-forest AGB estimates fromTanDEM-X data. Tropical forests account for about 50% of the world’s forested biomass and play critical roles in the control of atmospheric carbon dioxide by emission through deforestation and uptake through forest growth. The TanDEM-X InSAR data used in this analysis were taken over the Tapajós National Forest,...

Green areas, also known as green infrastructure or urban vegetation, are vital to urbanites for their critical roles in mitigating urban heat island effects and climate change and for their provision of multiple ecosystem services and aesthetics. Here, I provide a high spatial resolution snapshot of the green cover distribution of the city of San Juan, Puerto Rico, by incorporating the use of morphological spatial pattern analysis (MSPA) as a tool to describe the spatial pattern and connectivity of the city’s urban green areas. Analysis of a previously developed IKONOS 4-m spatial resolutio...

Urban activities and related infrastructure alter the natural patterns of stream physical and chemical conditions. According to the Urban Stream Syndrome, streams draining urban landscapes are characterized by high concentrations of nutrients and ions, and might have elevated water temperatures and variable oxygen concentrations. Here, we report temporal and spatial variability in stream physicochemistry in a highly urbanized watershed in Puerto Rico. The main objective of the study was to describe stream physicochemical characteristics and relate them to urban intensity, e.g., percent...

Young secondary forests and plantations in the moist tropics often have rapid rates of biomass accumulation and thus sequester large amounts of carbon. Here, we compare results from mature forest and nearby 15–20 year old tree plantations in lowland Costa Rica to evaluate differences in allocation of carbon to aboveground production and root systems. We found that the tree plantations, which had fully developed, closed canopies, allocated more carbon belowground - to their root systems - than did mature forest. This increase in belowground carbon allocation correlated significantly with...

Habitat fragmentation studies have produced complex results that are challenging to synthesize. Inconsistencies among studies may result from variation in the choice of landscape metrics and response variables, which is often compounded by a lack of key statistical or methodological information. Collating primary datasets on biodiversity responses to fragmentation in a consistent and flexible database permits simple data retrieval for subsequent analyses. We present a relational database that links such field data to taxonomic nomenclature, spatial and temporal plot attributes, and...

This paper presents initial efforts to establish the San Juan Urban Long-Term Research Area Exploratory (ULTRA-Ex), a long-term program aimed at developing transdisciplinary social-ecological system (SES) research to address vulnerability and sustainability for the municipality of San Juan. Transdisciplinary approaches involve the collaborations between researchers, stakeholders, and citizens to produce socially relevant knowledge and support decision-making. We characterize the transdisciplinary arrangement emerging in San Juan ULTRA-Ex as a knowledge-action network composed of multiple...

This paper examines how knowledge-action-systems the networks of actors involved in the production, sharing and use of policy-relevant knowledge - work in the process of developing sustainable strategies for cities. I developed an interdisciplinary framework- the knowledge-action system analysis (KASA) framework - that integrates concepts of the coproduction of knowledge and social order with social network analysis tools to analyze existing configurations of knowledge-action systems in the city of San Juan, Puerto Rico, and how these are shaping both what we know and how we envision the...

I examined the multiple visions of the future of the city that can emerge when city actors and organizations reconfigure themselves to address sustainability. In various cities worldwide, novel ideas, initiatives, and networks are emerging in governance to address social and ecological conditions in urban areas. However, cities can be contested spaces, bringing a plurality of actors, network configurations, preferences, and knowledge that shape the politics over desirable pathways for future development. I used the knowledge-action systems analysis (KASA) approach to examine the frames and...

Mona Island is the third largest island in the archipelago of Puerto Rico located about 70 km west of the main island. Presently it is a wilderness refuge that contains well-preserved arboreal and shrubby vegetation, and distinct cactus forests, covering the calcareous, elevated plateau. During a forest inventory conducted by the US Forest Service, we obtained leaves of 53 species constituting the vegetation canopy on the plateau of Mona Island. We conducted a biochemical characterization of these leaves based on analyses of carbon (C), nitrogen (N), acid detergent fiber (cellulose,...

We analyzed the nutritional composition and isotope ratios (C and N) of big-leaf mahogany (Swietenia macrophylla King) leaves in plantations established on contrasting soils and climates in Central America (State of Quintana Roo, Yucatan, Mexico) and South America (State of Para, Brazil). The objective was to determine the adaptability of this species to large differences in nutrient availability and rainfall regimes. Nutrient concentrations of leaves and soils were determined spectrophotometrically, and isotope ratios were measured using mass spectrometric techniques.In Para soils were...