Search

Most of the knowledge of tropical storm effects on forests is from studies conducted in reserves and protected areas. Effects on other settings such as urban forests, coastal forests, and in landscapes with mixed land uses and covers are, comparatively, less studied. Yet research from such forest types and landscape settings is needed to inform actions associated with management, mitigation, or restoration efforts before and after storms. Studies among various landscape settings, along with long-term observations, would offer unique insights into the varied and cumulative effects of tropical storms on forest ecosystems. We argue that these studies are urgently needed as various forest types within different landscape settings are a significant portion of the landscape affected by storms and other disturbances. Using Puerto Rico as a case study, we demonstrate that most tropical storm-forest studies are generated from a limited set of sites under conditions not representative of the most common forest types and landscape settings. We emphasize the need for broader research approaches in the range of forests that are exposed to tropical storms to advance understanding. Such an approach will provide valuable knowledge and understanding needed to inform and take actions across landscape settings, forest context, and socio-environmental conditions.

Coastal wetlands are shrinking rapidly due to land-use activities. Accelerated sea-level rise (SLR) associated to the warming climate is also affecting coastal wetlands, particularly in islands with limited coastal plains. We analyzed coastal wetland changes in Puerto Rico by applying the Sea Level Affecting Marshes Model under two scenarios by 2100. We also analyzed mortality and recruitment in a freshwater swamp dominated by the tree Pterocarpus officinalis Jacq. in the context of landscape saltwater-intrusion and drought. Our results indicate mangroves and estuarine water would replace the areas currently covered by other saltwater and freshwater wetlands, and saltmarsh would encounter the most relative loss among wetland types. A moderate SLR of 1 m by 2100 allows expansion of mangroves but would decrease saltmarsh and freshwater wetlands. A 2-m SLR would decrease the distributions of all vegetated wetlands, mostly replaced by estuarine water. In the P. officinalis forest, saltwater-intrusion and drought increased tree mortality during 2003–2015 compared to 1994–2003. Saltwater intrusion had a more significant negative effect on tree recruitment than on mortality in this Pterocarpus forest. Coastal wetlands are facing challenges to their persistence at current locations due to accelerated SLR, limited coastal lands, and a modified hydrological regime.

Streams and rivers of the Luquillo Experimental Forest, Puerto Rico, have been the subject of extensive watershed and aquatic research since the 1980s. This research includes understanding stream export of nutrients and coarse particulate organic matter, physicochemical constituents, aquatic fauna populations and community structure. However, many of the streams and watersheds studied do not appear in standard scale maps. We document recent collaborative and multi-institutional work to improve hydrological network information and identify knowledge gaps. The methods used to delimit and densify stream networks include establishment and incorporation of an updated new vertical datum for Puerto Rico, LIDAR derived elevation, and a combination of visual-manual and automated digitalization processes. The outcomes of this collaborative effort have resulted in improved watershed delineation, densification of hydrologic networks to reflect the scale of on-going studies, and the identification of constraining factors such as unmapped roadways, culverts, and other features of the built environment that interrupt water flow and alter runoff pathways. This work contributes to enhanced knowledge for watershed management, including attributes of riparian areas, effects of road and channel intersections and ridge to reef initiatives with broad application to other watersheds.

Hurricanes shape ecosystems. A broad range of forested ecosystems is particularly affected by hurricanes, thus creating the need for studies addressing the effects of these disturbances. There is a long history of hurricane and forest research on the Caribbean island of Puerto Rico. In this study, we present results from a systematic literature review of peer-reviewed articles regarding ecological research conducted in Puerto Rico on the topic of hurricanes and forests published from 1900 through 2017. We present a summary of cyclonic activity on the island during the study period and the results from the systematic literature review within this cyclonic context. We discuss findings in terms of aspects of forests studied, geographical distribution of study areas, and time scales at which research was conducted. These findings allow us to determine what was studied about hurricanes and forests, identify gaps in the information, and suggest possible areas of research and production of new knowledge that recent and future storms can bring. We conclude with recommendations identifying research needs and propose additional approaches to complement existing information. Our goal is to generate future knowledge from hurricane and forest research with the broadest applications possible.

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.

From islands with no permanent flowing streams to those with navigable inland waters, the insular Caribbean contains a great range of conditions regarding the access to freshwater resources. Because of the variation in topography and size, the ability of islands to retain freshwater also varies widely. The usage of freshwater in this region is being led by two major drivers: (1) the demands of basic water needs from an increasing urban population, and (2) those of tourism-based economies that demand water for recreation and aesthetic uses. Formal and informal freshwater management and conservation approaches vary from those being implemented at an individual level based on cultural practices, to those based on government programs. Although most islands have integrated watershed resources practices at some level, economic investment in infrastructure and social governance of water and environment need further evaluation and development. In this overview paper, a description of the natural environment associated to freshwater resources in the insular Caribbean is presented, noting also economic and climatic constraints. Opportunities for improvement in the management of Caribbean freshwater resources are discussed in light of the particular regional environmental context.

When landmasses and shapes. we look If (e.g., at it is a countries) a map, thematic we expect reflecting map; this to see is, their a the map actual portrayed that sizes dislandmasses (e.g., countries) reflecting their actual sizes and shapes. If t is a thematic ma ; hi is, a p that d splays information about a specific theme; the different units are colored according to the information displayed (what is known as a choropleth map), or with symbols representing either quantitative or qualitative information (for example, a proportional symbol map). In the case of the insular Caribbean, logically, the Greater Antilles occupy a larger extent than the Lesser Antilles and the small islands in the northern Caribbean (Map 1). Oftentimes, geographic patterns displayed on regional maps are not easily discernible, particularly for those islands with smaller sizes (this will depend, of course, on the scale and extent of the map). This can be problematic because the information, and ultimately the message that wants to be conveyed through a map, can be overlooked or missed due to the inherent size differences.

A BSTRACT. — Riparian zones are dynamic areas adjacent to flowing freshwater that connect aquatic and terrestrial environments. We measured individual tree distances relative to two permanent streams in the Luquillo Forest Dynamics Plot, Puerto Rico, to determine if tree species exhibit distinct affinities for riparian zones in a mid-montane tropical forest. In addition, we also calculated stem density, species richness, and diversity indices in 20 x 20 m randomly selected quadrats at different distances from the streams. We found that no single species in the study site was predominantly associated with riparian zones; however, almost all species were represented by a few stems in close proximity to streams. Multivariate (Fuzzy Set Ordination) ordination of plot species composition in relation to distance to streams indicated that there is greater variation in species composition closer to streams, and less variation in species composition farther from streams. This study suggests that in mid-montane wet forest, riparian zones include all tree species found throughout the forest landscape. R ESUMEN. — Las zonas riberenas son areas de gran dinamismo adyacentes a cuerpos de agua dulce que conectan a los ambientes terrestres con los acuaticos. Para determinar si hay especies de arboles que se encuentran exclusivamente asociadas a la zona riberena en un bosque humedo de montana, medimos la distancia de arboles individuales en relacion a dos quebradas permanentes en la Parcela de Dinamica Poblacional del Bosque de Luquillo, Puerto Rico. Tambien calculamos cantidad de tallos, riqueza de especies e indice de diversidad en cuadrantes 20 x 20 m que estaban a diferentes distancias de las quebradas. No encontramos especies que estuvieran exclusivamente en las zonas riberenas, sin embargo, casi todas las especies estaban representadas cerca de las quebradas. Encontramos una densidad mas alta de arboles cerca de las quebradas. Un analisis de ordenacion multivariado (Fuzzy Set Ordination) a base de composicion de especies y distancia a las quebradas de cuadrantes 20 x 20 m indico que la composicion de especies en cuadrantes cerca de las quebradas era mas variada que la composicion de especies de los cuadrantes a distancias mayores de 50 metros de las quebradas. Este estudio sugiere que en bosques humedos de montana las zonas riberenas incluyen todas las especies de arboles que se encuentran en el paisaje.

Extreme events (hurricanes, floods, and droughts) can influence upstream migration of macroinvertebrates and wash out benthic communities, thereby locally altering food webs and species interactions. We sampled palaemonid river shrimp (Macrobrachium spp.), dominant consumers in headwaters of the Luquillo Mountains of northeastern Puerto Rico, to determine their distributions along an elevational gradient (274–456 m asl) during a series of disturbances (Hurricane Hugo in 1989, a drought in 1994, and Hurricane Georges in 1998) that occurred over a 15-y period (1988−2002). We measured shrimp abundance 3 to 6 times/y in Quebrada Prieta in the Espiritu Santo drainage as part of the Luquillo Long-Term Ecological Research Program. In general, Macrobrachium abundance declined with elevation during most years. The lowest mean abundance of Macrobrachium occurred during the 1994 drought, the driest year in 28 y of record in the Espiritu Santo drainage. Macrobrachium increased in abundance for 6 y following t...

Long-term research on the response of wet forests in the Luquillo Experimental Forest (LEF) to natural and anthropogenic disturbances yielded information useful for the management of these forests and to a better understanding of the functioning of tropical forests and how species composition changes under different disturbance regimes. We summarize studies on basal area removal, response to ionizing radiation, and the effects of hurricanes and landslides on forested watersheds. We also review studies on forested stream biota following hurricane, drought, and flooding events. This chapter also evaluates reforestation of degraded lands and recovery of forests after abandonment of paved roads. All the studies combined cover the major land cover changes that take place throughout the tropics and which require attention to conserve tropical biodiversity. These changes range from limited extractions of resources from forests to deforestation and conversion to pastures. When tropical forests are converted to pastures, more intensive management actions are needed to restore lands, including planting of introduced species capable of growing on degraded lands. Results from the LEF have demonstrated the high resistance and resilience of tropical forests and the success of plantings in the restoration of forest cover on degraded lands. In both streams and forests, species composition shifts from native to introduced species when anthropogenic disturbance regimes become prevalent over the natural disturbance regimes.