USDA Forest Service International Institute of Tropical Forestry

San Juan, Puerto Rico

USDA Forest Service International Institute of Tropical Forestry

San Juan, Puerto Rico
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Van Beusekom E.A.,USDA Forest Service International Institute of Tropical Forestry | Gonzalez G.,USDA Forest Service International Institute of Tropical Forestry | Scholl A.M.,U.S. Geological Survey
Atmospheric Chemistry and Physics | Year: 2017

The degree to which cloud immersion provides water in addition to rainfall, suppresses transpiration, and sustains tropical montane cloud forests (TMCFs) during rainless periods is not well understood. Climate and land use changes represent a threat to these forests if cloud base altitude rises as a result of regional warming or deforestation. To establish a baseline for quantifying future changes in cloud base, we installed a ceilometer at 100ĝ€m altitude in the forest upwind of the TMCF that occupies an altitude range from ĝ1/4 600ĝ€m to the peaks at 1100ĝ€m in the Luquillo Mountains of eastern Puerto Rico. Airport Automated Surface Observing System (ASOS) ceilometer data, radiosonde data, and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite data were obtained to investigate seasonal cloud base dynamics, altitude of the trade-wind inversion (TWI), and typical cloud thickness for the surrounding Caribbean region. Cloud base is rarely quantified near mountains, so these results represent a first look at seasonal and diurnal cloud base dynamics for the TMCF. From May 2013 to August 2016, cloud base was lowest during the midsummer dry season, and cloud bases were lower than the mountaintops as often in the winter dry season as in the wet seasons. The lowest cloud bases most frequently occurred at higher elevation than 600ĝ€m, from 740 to 964ĝ€m. The Luquillo forest low cloud base altitudes were higher than six other sites in the Caribbean by ĝ1/4 200-600ĝ€m, highlighting the importance of site selection to measure topographic influence on cloud height. Proximity to the oceanic cloud system where shallow cumulus clouds are seasonally invariant in altitude and cover, along with local trade-wind orographic lifting and cloud formation, may explain the dry season low clouds. The results indicate that climate change threats to low-elevation TMCFs are not limited to the dry season; changes in synoptic-scale weather patterns that increase frequency of drought periods during the wet seasons (periods of higher cloud base) may also impact ecosystem health. © Author(s) 2017.

Manrique-Hernandez H.,University of Puerto Rico at San Juan | Heartsill-Scalley T.,USDA Forest Service International Institute of Tropical Forestry | Barreto-Orta M.,University of Puerto Rico at San Juan | Betancourt-Roman C.M.,University of Oregon | Ortiz-Zayas J.R.,University of Puerto Rico at San Juan
Ecological Restoration | Year: 2016

Today there is a wide variety of approaches on how to determine when a river restoration project can be considered ecologically successful. The limited information on river restoration responses renders this practice a subjective component of river management. We aimed to contribute to this issue by assessing the ecological outcomes of a restoration project conducted in Quebrada Chiclana, a first-order tropical stream located in the headwaters of the Rio Piedras in the city of San Juan, Puerto Rico. We focused on the reforestation component of the restoration project using current structure and composition of riparian vegetation as an indicator of restoration success. Recovery of riparian vegetation was studied eight years after restoration using a forest succession approach. We conducted a vegetation census and measured structural variables on vegetation at restored and nearby reference areas. We encountered a riparian vegetation community composed of 35 tree and 84 non-tree species. The non-native trees tall albizia (Albizia procera) and African tuliptree (Spathodea campanulata) were the most abundant tree species within the study area. We observed 11 out of the 16 woody species initially proposed in the reforestation plan but with lower tree density than proposed. Even though we demonstrate that the river restoration project has not yet met its reforestation objectives, our results show recovery of the vegetation community in the impacted area has occurred through natural succession. © 2016 by the Board of Regents of the University of Wisconsin System.

Ramirez A.,University of Puerto Rico at San Juan | Rosas K.G.,University of Puerto Rico at San Juan | Lugo A.E.,USDA Forest Service International Institute of Tropical Forestry | Ramos-Gonzalez O.M.,USDA Forest Service International Institute of Tropical Forestry
Ecology and Society | Year: 2014

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 impervious surface cover, and watershed infrastructure, e.g., road and pipe densities. The Río Piedras Watershed in the San Juan Metropolitan Area, Puerto Rico, is one of the most urbanized regions on the island. The Río Piedras presented high solute concentrations that were related to watershed factors, such as percent impervious cover. Temporal variability in ion concentrations lacked seasonality, as did all other parameters measured except water temperature, which was lower during winter and highest during summer, as expected based on latitude. Spatially, stream physicochemistry was strongly related to watershed percent impervious cover and also to the density of urban infrastructure, e.g., roads, pipe, and building densities. Although the watershed is serviced by a sewage collection system, illegal discharges and leaky infrastructure are probably responsible for the elevated ion concentration found. Overall, the Río Piedras is an example of the response of a tropical urban watershed after major sewage inputs are removed, thus highlighting the importance of proper infrastructure maintenance and management of runoff to control ion concentrations in tropical streams.

Munoz-Erickson T.A.,USDA Forest Service International Institute of Tropical Forestry | Lugo A.E.,USDA Forest Service International Institute of Tropical Forestry | Quintero B.,New York University
Ecology and Society | Year: 2014

The synthesis of the contributions in this special issue about the tropical city of San Juan has resulted in five themes. First, the city is subject to multiple vulnerabilities, but socioeconomic factors and education level affect the perception of citizens to those vulnerabilities, even in the face of imminent threat. Second, in light of the social-ecological conditions of the city, how its citizens and institutions deal with knowledge to respond to vulnerabilities becomes critical to the adaptive capacity of the city. Third, the relationship between socioeconomic factors and green cover, which in 2002 covered 42% of the city, is not what has been reported for other temperate zone cities. In San Juan, neighborhoods with households of high socioeconomic level were not necessarily associated with greater green cover. However, in adjacent neighborhoods within the densely populated zones of the city, households of high socioeconomic level did preserve green cover better than households in lower socioeconomic-level neighborhoods. Fourth, tropical conditions such as climate may explain some of the unique aspects of the social-ecological system of San Juan. The most obvious is the exuberance of tropical biota in the city that not only forms novel species assemblages but also provides many ecological services, including food production for up to 60% of the members of particular neighborhoods. Ecosystem resilience is particularly high in aquatic and terrestrial ecological systems in San Juan. Fifth, it appears that the emergence of novel systems in the city represent adaptive responses to the social end ecological conditions in the city. We conclude that the study of a tropical city provides contrast to the prevailing literature on temperate and boreal cities and expands the suite of behaviors of urban social-ecological systems, thus advancing the dialogue on the functioning of cities in light of environmental change. © 2014 by the author(s).

McGinley K.A.,USDA Forest Service International Institute of Tropical Forestry | Cubbage F.W.,North Carolina State University
Journal of Sustainable Forestry | Year: 2012

We evaluated how governmental forest regulation in Costa Rica, Guatemala, and Nicaragua has succeeded or failed in fostering changes in forest owner and user behavior that enhance the sustainability of tropical forest management. As expected, sufficient resources and capacity for forest policy implementation are crucial for attaining governmental forest policy objectives, but innovative arrangements for promoting, enforcing, and verifying policy compliance can compensate for limited regulatory resources and processes. The findings also indicate that: the level of governmental commitment to sustainable forest management (SFM) was as important as total funding levels; a mix of government rules and incentives enhanced adoption of SFM; the incorporation of professional forest regents offset limited agency capacity; and forest certification enhanced SFM on forest concessions. Local level inducements and constraints that enhance or impede governmental forest policy adoption and compliance also were identified. © 2012 Copyright Taylor and Francis Group, LLC.

Ramos-Gonzalez O.M.,USDA Forest Service International Institute of Tropical Forestry
Ecology and Society | Year: 2014

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 resolution classification of the city of San Juan from 2002 revealed a larger area of vegetation (green areas or green infrastructure) than previously estimated by moderate spatial resolution imagery. The city as a whole had approximately 42% green cover and 55% impervious surfaces. Although the city appeared greener in its southern upland sector compared to the northern coastal section, where most built-up urban areas occurred (66% impervious surfaces), northern San Juan had 677 ha more green area cover dispersed across the city than the southern component. MSPA revealed that most forest cover occurred as edges and cores, and green areas were most commonly forest cores, with larger predominance in the southern sector of the municipality. In dense, built-up, urban land, most of the green areas occurred in private yards as islets. When compared to other cities across the United States, San Juan was most similar in green cover features to Boston, Massachusetts, and Miami, Florida. Per capita green space for San Juan (122.2 m²/inhabitant) was also comparable to these two U.S. cities. This study explores the intra-urban vegetation variation in the city of San Juan, which is generally overlooked by moderate spatial resolution classifications in Puerto Rico. It serves as a starting point for green infrastructure mapping and landscape pattern analysis of the urban green spaces within the city of San Juan. The effectiveness of research and city planning will be further enhanced as a result of this type of finer-scale urban cover exploration. © 2014 by the author(s).

Lugo A.E.,USDA Forest Service International Institute of Tropical Forestry
Biotropica | Year: 2010

Cities contain over half of the world's population and are the source of many anthropogenic effects on the world's biota. Close examination of San Juan, Puerto Rico, a tropical city, reveals a significant green infrastructure. The city contains natural and human-constructed forests, urban aquatic systems with native and introduced species, and a thriving and diverse biota adapted to urban conditions. It behooves tropical ecologists to pay attention to the biodiversity of urban environments to learn lessons about ecological persistence and adaptation to novel anthropogenic environments. © 2010 The Author(s). Journal compilation © 2010 by The Association for Tropical Biology and Conservation.

Van Beusekom A.E.,USDA Forest Service International Institute of Tropical Forestry | Gonzalez G.,USDA Forest Service International Institute of Tropical Forestry | Rivera M.M.,USDA Forest Service International Institute of Tropical Forestry
Earth Interactions | Year: 2015

As is true of many tropical regions, northeastern Puerto Rico is an ecologically sensitive area with biological life that is highly elevation dependent on precipitation and temperature. Climate change has the potential to increase the risk of losing endemic species and habitats. Consequently, it is important to explore the pattern of trends in precipitation and temperature along an elevation gradient. Statistical derivatives of a frequently sampled dataset of precipitation and temperature at 20 sites along an elevation gradient of 1000m in northeastern Puerto Rico were examined for trends from 2001 to 2013 with nonparametric methods accounting for annual periodic variations such as yearly weather cycles. Overall daily precipitation had an increasing trend of around 0.1mmday21 yr21. The driest months of the annual dry, early, and late rainfall seasons showed a small increasing trend in the precipitation (around 0.1mmday-1 yr-1). There was strong evidence that precipitation in the driest months of each rainfall season increased faster at higher elevations (0.02mmday21 more increase for 100-m elevation gain) and some evidence for the same pattern in precipitation in all months of the year but at half the rate. Temperature had a positive trend in the daily minimum (around 0.028Cyr-1) and a negative trend in the daily maximumwhose size is likely an order of magnitude larger than the size of the daily minimum trend. Physical mechanisms behind the trends may be related to climate change; longer-term studies will need to be undertaken in order to assess the future climatic trajectory of tropical forests. © 2015, American Meteorological Society. All right reserved.

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