Species Composition and Differences in Diversity Among the Pterocarpus Ofﬁcinalis Forested Wetlands of Puerto Rico

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Species composition and differences in diversity among the Pterocarpus ofﬁcinalis forested wetlands of Puerto Rico

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The user has requested enhancement of the downloaded file. Caribbean Naturalist No. 4 2013 Species Composition and Differences in Diversity Among the Pterocarpus officinalis Forested Wetlands of Puerto Rico Rusty A. Feagin, Frances Toledo-Rodríguez, Ricardo J. Colón-Rivera, Fred Smeins, and Roel Lopez The Caribbean Naturalist . . . ♦ A quarterly peer-reviewed and edited interdisciplinary natural history science journal with a regional focus on the Caribbean ( ISSN 2326-7119 [online]). ♦ Featuring research articles, notes, and research summaries on terrestrial, fresh-water, and marine organisms, and their habitats. The journal's versatility also extends to publishing symposium proceedings or other collections of related papers as special issues. ♦ Focusing on field ecology, biology, behavior, biogeography, taxonomy, evolution, anat- omy, physiology, geology, and related fields. Manuscripts on genetics, molecular biology, anthropology, etc., are welcome, especially if they provide natural history insights that are of interest to field scientists. ♦ Offers authors the option of publishing large maps, data tables, audio and video clips, and even powerpoint presentations as online supplemental files which will be linked to the full-text version of the journal in the BioOne.org database.

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Cover Photograph: Traversing a tidal creek in the secondary Pterocarpus officinalis forest in la Reserva Natural de Humacao, Puerto Rico.. Photograph © Doel Delgado. CARIBBEAN NATURALIST Board of Editors James D. Ackerman, Department of Biology, University of Puerto Rico at Río Piedras, USA Alfonso Aguilar-Perera, Department of Marine Biology, Universidad Autónoma de Yucatán, Mexico Wayne J. Arendt, International Institute of Tropical Forestry, Luquillo, Puerto Rico, USA Rüdiger Bieler, Field Museum of Natural History, Chicago, IL, USA Leo Douglas, Department of Geography/Geology, University of the West Indies, Mona, Jamaica Robert Erdman, Department of Biological Sciences, Florida Gulf Coast University, Fort Myers, FL, USA Keith Goldfarb, Eagle Hill Institute, Steuben, ME, USA ... Editor-in-Chief Grizelle González, International Institute of Tropical Forestry, San Juan, Puerto Rico, USA Gary R. Graves, Department of Vertebrate Zoology, Smithsonian Institution, Washington, DC, USA S. Blair Hedges, Department of Biology, Pennsylvania State University, University Park, PA, USA Julia A. Horrocks, Dept. of Biological and Chemical Sciences, Univ. of the West Indies, Cave Hill Campus, Barbados Scott Jones, Smithsonian Institution, Caribbean Coral Reef Ecosystems, Carrie Bow Cay, Belize Heather Judkins, Department of Biological Sciences, University of South Florida, St. Petersburg, FL, USA Craig A. Layman, Department of Biological Sciences,Florida International University, North Miami, FL, USA John Leavengood, Department of Entomology, University of Kentucky, Lexington, KY, USA Antonio A. Mignucci-Giannoni, Manatee Conservation Center, Inter American University, Bay- amón, Puerto Rico, USA Gregg Moore, Department of Biological Sciences, Jackson Estuarine Laboratory, University of New Hampshire, Durham, NH, USA Robert Powell, Department of Biological Sciences, Avila University, Kansas City, MO, USA Chris Rimmer, Vermont Center for Ecostudies, Norwich, VT, USA Armando Rodríguez-Durán, Dean for Research, Inter American University, Bayamón, Puerto Rico, USA Noris Salazar Allen, Smithsonian Tropical Research Institute, Panama Inés Sastre de Jesus, Biology Department, University of Puerto Rico at Mayagüez, USA J. Angel Soto-Centeno, Florida Museum of Natural History, Division of Mammals, Gainesville, FL, USA Christopher Starr, Department of Life Sciences, University of the West Indies, St. Augustine, Trini- dad and Tobago David W. Steadman, Florida Museum of Natural History, Gainesville, FL, USA Kathleen Sullivan Sealey, Department of Biology, University of Miami, Coral Gables, FL, USA Jarrod M. Thaxton, Department of Biology, University of Puerto at Mayagüez, USA Jason M. Townsend, Department of Wildlife, Fish and Conservation Biology, University of Califor- nia-Davis, USA ... Managing Editor Jill Weber, Eagle Hill Institute, Steuben, ME, USA ... Production Editor Byron Wilson, Department of Life Sciences, University of the West Indies at Mona, Kingston, Jamaica Graham A. J. Worthy, Department of Biology, University of Central Florida, Orlando, FL, USA Joseph M. Wunderle, International Institute of Tropical Forestry, University of Puerto Rico at Río Píedras, USA

The Caribbean Naturalist (ISSN # 2326-7119) is published by the Eagle Hill Institute, PO Box 9, 59 Eagle Hill Road, Steuben, ME 04680-0009. Phone 207-546-2821, FAX 207-546-3042. E-mail: [email protected]. Webpage: www.eaglehill.us/cana. Copyright © 2013, all rights reserved. Periodical postage paid in Steuben, ME and additional mailing offices. Published quarterly. Special issue proposals are welcome. On-line secure subscription ordering: rate per year for Caribbean subscribers - $15 regular, $10 students, $60 organizations; for Non-Caribbean subscribers - $20 regular, $15 students, $80 organizations. Journal subscription exchanges are considered. Authors: submission guidelines are available at www.eaglehill.us/cana. Co-published journals: The Northeastern Natu- ralist (ISSN 1092-6194 [print], ISSN 1938-5307 [online]) and the Southeastern Naturalist (ISSN 1528-7092 [print], ISSN 1938-5412 [online]), journals with separate Boards of Editors. The Eagle Hill Institute is a tax exempt 501(c)(3) nonprofit corporation of the State of Maine (Federal ID # 010379899). 20132013 CARIBBEANCaribbean Naturalist NATURALIST No. 4:1–25No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez

Species Composition and Differences in Diversity Among the Pterocarpus officinalis Forested Wetlands of Puerto Rico

Rusty A. Feagin1,*, Frances Toledo-Rodríguez2, Ricardo J. Colón-Rivera1, Fred Smeins1, and Roel Lopez3

Abstract - Pterocarpus officinalis (Dragonsblood Tree, known as Palo de Pollo in Puerto Rico)-dominated forests are a rare ecosystem, found only in fifteen locations in Puerto Rico, most of which are adjacent to the coast and are at risk from sea level rise, nutrient pollution, upstream hydrological modifications, and deforestation. Prior to this study, there was little information on the diversity of organisms inhabiting these forests. The central objectives of our study were to examine the diversity and species composition of three Pterocarpus forests in Puerto Rico located in Humacao, Patillas, and Dorado; compare and contrast diversity among the three forests; and identify possible differences caused by human influences or natural factors. Visual surveys, vegetation plots, pitfall traps, insect traps and nets, and audio recordings were carried out to collect records of birds, mammals, amphibians and reptiles, invertebrates (insects, crustaceans, mollusks), plants, and fungi. The Dorado Pterocarpus forest is only 2.4 ha in extent, but is the rich- est and most diverse; Humacao, the largest tract sampled at 150 ha (63% of the total Pterocarpus coverage in Puerto Rico), is the least rich and diverse. The most obvious factor influencing richness and diversity among the forests is the adjacent land cover and history of the sites. Saltwater intrusion (Humacao), freshwater inflow from watersheds (Humacao, Dorado), and emerging spring water sources (Patillas) may also be factors that alter richness and diversity. Our results will be useful to those planning the appropriate management of this ecosystem in the context of ongoing sea-level rise, climate change, nutrient pollution, upstream hydrological modifications, and deforestation.

Introduction Tropical wetlands are considered among the most valuable (Costanza et al. 1989) and important ecosystems in the world because of the ecosystem services they provide (e.g., flood protection, wildlife habitat; Mitsch and Gosselink 2007). Forested wetlands, in particular, are a feature of low-lying coastal areas in the Ca- ribbean region (Bacon 1990). Rhizophora mangle L. (Red Mangrove) dominates most of these wetlands except for forested areas influenced by freshwater, where the leguminous tree Pterocarpus officinalis Jacq. (Dragonsblood Tree, known as Palo de Pollo in Puerto Rico) is the dominant species (Fig. 1; Weaver 1997). Adapted to flooded ecosystems, P. officinalis inhabits river floodplains, coastal basins, and subtropical rainforests (Alvarez-Lopez 1990). Due to human disturbance and land clearing, Pterocarpus wetlands are now limited to small, genetically isolated

1Department of Ecosystem Science and Management, Texas A&M University, College Station, TX , USA 77845. 2US Fish and Wildlife Service, Parker River National Wildlife Refuge, Newburyport, MA, USA 01950. 3Institute of Renewable Natural Resources, Texas A&M University, College Station, TX, USA 77843. *Corresponding author - feaginr@tamu. edu. 1 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez

Figure 1. A Pterocarpus officinalis tree during the dry season in the secondary re-growth section of the Humacao Natural Reserve forest (H2 section of forest), in Humacao, PR, USA. Photograph © Doel Delgado. 2 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez patches scattered throughout the Caribbean region (Muller et al. 2009, Rivera-Oca- sio et al. 2006). Although the floristic composition of these wetlands has been well described by Alvarez-Lopez (1990) and Imbert et al. (2000), these ecosystems have not received the same research attention as mangrove swamps or upland rainforests (Imbert et al. 2000). In the last century, Puerto Rico lost nearly all of its Pterocarpus forested wetland cover (Helmer 2004), due largely to clearing of the coastal plain for agricultural purposes, often to establish sugarcane plantations. Today, the total area of Ptero- carpus is estimated to cover only 261 ha in approximately 15 locations (Gould 2007). Furthermore, remnant Pterocarpus wetlands in Puerto Rico are restricted to the coast, abutting mangrove ecosystems (Cintrón 1983); the remaining stands now occur near their ecological limits in terms of salinity (Rivera-Ocasio et al. 2007). Though work has also been done on drought tolerance (Lopez and Kursar 2007) and nutrient depletion (Medina et al. 2008), sea-level rise and associated saltwater intrusion appear to be the most serious threats affecting the Pterocarpus ecosystem. Salinities above approximately 12% can kill populations of these trees (Rivera- Ocasio et al. 2007). Pterocarpus wetland forests sustain a unique set of fauna, mainly composed of reptiles, water birds, amphibians, crustaceans, and mollusks (Quiñones-Ramos et al. 1992). This wetland forest type is recognized as rare and limited in extent on the island by the Puerto Rico National Heritage Program (Schwartz 2004). The importance of Pterocarpus wetland forests rests on their rarity, high level of biological productivity, and floral composition. These ecosystems are also of interest to science, and they have intrinsic social value (Figueroa et al. 1984) in terms of recreational and spiritual purposes. The biodiversity of these Puerto Rican wetlands is one factor that has resulted in their designation as a protected ecological resource (Commonwealth of Puerto Rico 2008). However, little is known about the differences in species composition among these forests in Puerto Rico, and the potential causes for these differences. Is there any variance in composition among sites? Is diversity highest in relatively natural areas, or in areas altered by humans? What are the most likely causes for any potential differences: temperature, precipitation, salinity, proximity to the coast, soil parameters, or land-use history? The central objective of this work was to examine the diversity and species composition of three Pterocarpus forests in Puerto Rico (Humacao Natural Reserve, Dorado Pterocarpus Forest Natural Protected Area, and Punta Viento Wetland Natu- ral Reserve). We chose these three forests based on their relative sizes, locations, level of community interest in their preservation, and our ability to gain access to them (Fig. 2). The specific objectives of this project were to sample and list a wide range of plant and animal species, and then to compare and contrast the diversity among the three forests, and determine if differences are caused by human influences or natural factors.

3 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez

Field Site Description Humacao Natural Reserve The Humacao Natural Reserve (HNR), in Puerto Rico, contains the largest and best preserved Pterocarpus forest in the United States, yet the forested stand is only 150 ha in size (representing over half of Pterocarpus forest cover in the US; Alvarez-Lopez, 1990). Much of the original forest acreage was converted for sugarcane production, and eventually into flooded lagoons (Fig. 2b, c). The reserve is currently managed by the Departamento de Recursos Naturales y Ambientales (DRNA). The community of Punta Santiago sits immediately adjacent to the forest, between the lagoons and the ocean. This low-income residential area flooded repeatedly after the 1970s, in part because there was reduced forest cover to absorb and reduce runoff. Subsequently, in 2000, the US Army Corps of Engineers modi- fied the Antón Ruiz River and several other drainages to open a connection between the lagoons and the ocean to allow floodwaters to flow into the ocean (Schwartz 2004). Unfortunately, this has also increased saltwater intrusion into the lagoons and the adjacent Pterocarpus forest (Ferrer 2007). The remnant Pterocarpus wetlands are now threatened by saltwater intrusion due to rising global sea levels, a problem that may be exacerbated by climate change over the next decades.

Dorado Pterocarpus Forest Natural Protected Area (DPFNPA) The DPFNPA forest was donated to the Puerto Rico Conservation Trust in 1995 by the developers of a housing project, as required by the Planning Board (Junta de Planificación), and it is managed by the Fideicomiso de Conservación de Puerto Rico. The forest is located within the property of the Dorado Beach Hotel Corpo- ration, a luxury resort community (Fig. 2d, e). The forest is considered to be the best remaining example of a Pterocarpus forest community on the north coast of the island. The DPFNPA forest covers 2.4 ha. Endangered species like Peltophryne lemur Cope (Puerto Rican Crested Toad), Eleutherodactylus karlschmidti Grant (Web-Footed Coqui), Sabicea cinerea Aubl. (Largeflower Woodvine), and Epi- crates inornatus Reinhardt (Puerto Rican Boa) are known to occur in this forest (Figueroa et al. 1984, Quiñones-Ramos et al. 1992). In 1984, the USDA repeated a 1926 study (Gleason and Cook 1926) and found no change in composition of the climax swamp forest formed by Pterocarpus officinalis and six other tree species in the 54 years between studies (1926–1984). However, total forested area was reduced by 30 percent over this time period. The primary cause of the forest cover loss was anthropogenic tree-cutting and hydrological modifica- tion. Construction of a golf course west of the study area altered drainage patterns, resulting in declines of both Pterocarpus and other secondary forest.

Punta Viento Wetland Natural Reserve in Patillas The Patillas forest is located on the south coast of Puerto Rico in El Bajo sector of the Municipality of Patillas (Fig. 2f, g). The forest covers an area of 4.6 ha and is enclosed within the Patillas Punta Viento Wetland Natural Reserve. The reserve

4 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez

Figure 2. (a) Pterocarpus forest study site locations across Puerto Rico; Humacao, (b) in 1977 and (c) 2006; Dorado, (d) in 1962 and (e) 2006; Patillas, (f) in 1967 and (g) 2006. Stars represent sampled forest sections in (b-g). Imagery courtesy of USGS (2013). 5 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez contains more than 500 acres of wetlands. In 2008, a community-based organiza- tion, Frente Ambiental Amigos de la Naturaleza, Patillas, urged legislators to pass Act No. 92 (Commonwealth of Puerto Rico 2008), designating the wetlands of Punta Viento as an ecological reserve to be managed by the DRNA.

Methods Sampling and identification of organisms We sampled a wide range of plant and animal species at the 3 different Ptero- carpus forests in Puerto Rico (Humacao, Patillas, and Dorado). The second author (F. Toledo-Rodríguez) identified organisms to the lowest taxonomic level possible in two sections of each forest. Taxonomy can be referenced in several databases by authority (Bird Life International 2013, Encylopedia of Life 2013, USDA 2013). The Dorado and Patillas forests were relatively small, and the sampled sections were close together (approximately 67 m and 141 m between the sampled sections, respectively) and, thus, we assumed them to be similar. Subsequently, we grouped the section-level data to present a single list for each forest. In contrast, the Humacao forest was relatively large and contained 2 different sections (approximately 1755 m apart). The Humacao 1 (H1) section was composed of primary forest that had not been cut since Pre-Columbian times, and had exclu- sively freshwater inputs, whereas the Humacao 2 (H2) section was composed of secondary re-growth following a tree harvest in the 1920s; it has both saltwater and freshwater inputs. We present the lists for each section of Humacao separately where applicable. We established two 100 m-long parallel transects in each section of forest. Each transect line had five points spaced 20 m apart (Fig. 3a). The first transect was used to survey birds, amphibians, reptiles, invertebrates, vegetation, and fungi, and the second was used to identify birds only. We chose this sampling scheme based on rapid-assessment techniques commonly used by US federal agencies. We collected or recorded all organisms during four 2–4 day sample sessions over a 2-year period, with at least 2 sessions in the rainy season and two in the dry season (Table 1). The driest months in Puerto Rico are December–April and the wettest months are May–November.

Table 1. Sampling dates for the forests, 2011–2012.

Session I Session II Session III Session IV Humacao Natural Reserve 13, 17 Nov 15, 16 March 23, 24 Dec 1, 2 May 11, 12 Jan 6, 7 May

Dorado Pterocarpus Forest 28, 29 Nov 22, 23 March 20 Dec 15, 16 April Natural Protected Area 19, 20 Jan 17, 18 April 8, 9 Jan

Punta Viento Wetland Natural 18, 19 Nov 20, 21 March 17, 18 Jan 11, 12 April Reserve, Patillas 13, 14 April

6 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez We conducted bird surveys from 7:00–7:30 AM (UTC-4). We recorded all birds seen and heard during a 5-minute period, within a 5-m radius around each point on the transect (Bibby et al. 1998, Hill et al. 2005). We placed audio recording equip- ment (Olympus, Olympus Linear Recorder, LS-11) in the deepest part of the forest (last point on the transect lines) and left it overnight to record both amphibian and bird vocalizations. We identified organisms to the lowest taxonomic level possible by listening to the audio recording for 10 minutes at intervals of every hour throughout the duration of the recording. Additionally, we surveyed for reptiles and amphibians from 9:00–9:30 AM through visual observation and traps. We placed pitfall traps (1.5 gallons) with an opening of 27.75 cm at each transect point and recovered them 24 hours later (Corn and Bury 1990, Hill et al. 2005, Lambert 2002). The overnight recordings described above were particularly useful for our identifications of the endemic coquís. To collect insects, we placed 16-ounce pitfall traps at each transect point and recovered them 24 hours later (Grootaert et al. 2010, Raghavendra et al. 1990). Additionally, we placed baited hanging traps and ground-level traps at the deepest part of the forest transect for a 24-hour period, after which we retrieved them and identified trapped organisms. We sampled vegetation at each point along all transects (Fig. 3b). To estimate the understory cover, we established a 10-m transect perpendicular to the primary transect at each point and recorded the percent cover by species within ten 1-m2 quadrats (Fidelibus and MacAller 1993, Hill et al. 2005). We defined understory

Figure 3. Within each forest section, (a) sampling points and traps were placed along two parallel transects, (b) with vegetation sampling centered on a transect point.

7 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez as the vegetation at the lower level in the forest, below 1.3 m in height. We also recorded the percentage of the ground that was covered by woody Pterocarpus officinalis roots in these quadrats. For tree samples, we used circular plots with a 5-m radius centered around each point and divided the plots into four quadrants. For each quadrant, we identified all tree species present and measured the diameter at breast height (dbh) of the 5 largest trees. We measured dbh 1.3 m from the ground and included the buttress root width, which can be relatively large on Pterocarpus trees. We quantified the percent cover of the upper forest canopy using a spherical crown densiometer and recorded canopy cover for the largest single tree at every quadrant, for a total of 4 trees per point. We measured canopy cover for each tree at the 4 cardinal directions (north, east, south, and west) and recorded the average of these values as the canopy cover for each tree. We then averaged the single- tree canopy cover values to estimate the canopy cover in the transect area. For reference, we used LIDAR data from another unpublished study (William Gould, International Institute of Tropical Forestry, US Forest Service, San Juan, Puerto Rico, USA, unpubl. data) (in H1) to estimate the canopy height, which was ≈30 m for the largest trees, though height varies greatly by forest location and section. Fungi and fishes were also surveyed when we encountered them along the transects (Backiel 1980, BCME 1997, Hill et al. 2005, Schieck and Stambaugh 2006). We then compared species composition and variety among the different forests, and we categorized each species as endemic, native, common resident, visitor, or introduced. We calculated Shannon’s diversity index as the total of all species within an organismal group, and for all species together, for a particular forest. Shannon’s diversity index (H') was calculated for each forest using the following formula: s

H' = ∑ -(Pi * ln Pi), i = 1 where S is the species count and Pi is the relative abundance of each species (i.e., the total number of observations of the species divided by the total number of observations).

Soil, land cover, and environmental factors We sought to identify the environmental differences among the three forests that were related to human influences or natural factors. We used NOAA-NCDC (2013) temperature and precipitation records from 1980–2010 recorded at nearby stations. The station name is Dorado 2 WnW PR for the Dorado Forest data, Patillas PR US and Guayama 2E, PR US for the Patillas forest, and Roosevelt Roads for the forest in Humacao. We collected soil samples from each forest, beginning at the surface and taking samples at every 10 cm to a depth of 40 cm. We immediately placed samples in bags and sent them to Servi-Tech Laboratories to determine percent nitrate-nitrogen, phosphorus, potassium, sulfur, calcium, magnesium, sodium, organic matter, soil pH, buffer pH, soluble salts, cation exchange capacity, and base saturation. We used GIS to digitize and map the land cover that surrounded each forest. Land cover classes included Pterocarpus forest, agricultural or human-managed,

8 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez non-Pterocarpus forest, pasture, forest and pasture mix, mangrove forest, marsh, open water, palm forest, and urban. We then measured the distance from each forest to the following closest features: house, street, ocean, agricultural land, and human-managed area. We used cover classes and distances to determine the possible human influence on the forest.

Results Sampling and identification of organisms Among all Pterocarpus officinalis forests, we found 39 species of birds (Table 2). Dorado, Patillas, and Humacao had 33, 23, and 21 species, respectively. The primary section of forest in Humacao (H1) had 11 bird species and the secondary section (H2) had 19 species. After visiting each forest 6 times, the number of newly-identified organisms slowed for nearly all organisms except for birds (Fig. 4). It appeared that the sampling effort had not yet detected all birds at Do- rado or Patillas, though the numbers at Humacao had begun to level out (Fig. 4c). These species sampling-effort curves demonstrate that, because we generally did not detect new species beyond the fifth visit, our sampling effort proved adequate for most organisms. Among all forests, we found 17 species of amphibians and reptiles. Dorado, Pa- tillas, and Humacao had 15, 10, and 11 species, respectively (Table 3). The primary section of forest in Humacao (H1) had 10 species, while the secondary section (H2) had 11.

Figure 4. Species-sampling effort curves for birds, amphibians and reptiles, and invertebrates for Dorado (a), Patillas (b), and Humacao (c). 9 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez

√ √ √ √ √ √ √ √ √ √ √ √ √ √ H2

√ √ √ √ √ √ √ √ √ H1

P √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √

√ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ D

Common resident Native Native Migrant Visitor Common resident, near threatened Invasive, 1955 Endemic Introduced, 1970 Common resident Rare visitor Endemic Common resident Endemic Visitor Permanent resident Common resident Common resident Endemic Introduced, 1912 Common resident Native Common resident Common resident Common resident Common resident Visitor Status Common resident Common resident Endemic

oodpecker

arbler

Scaly-naped Pigeon Caribbean Martin Antillean Grackle Greater Osprey Northern Parula White-crowned Pigeon Shiny Cowbird Puerto Rican Flycatcher Monk Parakeet Night-Heron Yellow-crowned Ruddy Duck Puerto Rican W Puerto Rican Northern Mockingbird Adelaide's W Adelaide's W Prairie Common Moorhen Puerto Rican Oriole Thrasher Pearly-eyed Puerto Rican Screech-Owl White-winged Parakeet Red-tailed Hawk Green Heron Mangrove Cuckoo Bananaquit Ani Smooth-billed Great Egret Great Blue Heron English common name Grasshopper Sparrow Antillean Mango Green Mango

Paloma Turca Paloma Golondrina Caribeña Mozambique, Chango Águila de Mar Paloma Cabeciblanca

Reinita Pechidorada Juí de Puerto Rico Común Yaboa Pato Chorizo Perico Monje Tordo Lustroso Tordo Carpintero de Puerto Rico Ruiseñor Mucaro Común / Mucarito Reinita Mariposera Reinita Galana Gallareta Común Calandria Zorzal Pardo Guaraguao Judío Garrapatero Perico Ali-Amarillo Perico Martinete Bobo Menor Reinita Garza Real Garzon Cenizo Spanish common name Zumbador Dorado de Puerto Rico Verde Zumbador Gorrión Chichara Vieillot

Müller

Gmelin Baird Gmelin

L. L. Vieillot L. L. L. L. odias L. ops fuscatus Vieillot Progne dominicensis Progne Patagioenas squamosal Bonnaterre Quiscalus niger Boddaert Pandion haliaetus Parula americana L. Patagioenas leucocephala L. Myairchus antillarum Myairchus Nyctanassa violacea L. Molothrus bonariensis Myiopsitta monachus Boddaert Oxyura jamaicensis Gmelin Melanerpes portoricencis Daudin Mimus polyglottos L. Dendroica adelaidae Dendroica Dendroica discolor Dendroica Gallinula chloropus Icterus dominicensis L. Margar Megascops nudipes Daudin Brotogeris versicolurus Brotogeris Coccyzus minor Gmelin flaveola Coereba ani Crotophaga Buteo jamaicensis. Gmelin Butorides virescens Ardea Her Ardea Ardea alba Ardea Ammodramus savannarum Gmelin Anthracothorax viridis Audebert & Table 2. Birds surveyed in the forests. D = Dorado forest, P = Patillas forest. H1 Humacao primary forest, H2 secondary 2. Birds surveyed in the forests. D = Dorado forest, P Table Scientific name Anthracothorax dominicus L.

10 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez

√ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ H2 H2

√ √ √ √ √ √ √ √ √ √ √ √ H1 H1

P √ √ √ √ √ √ P √ √ √ √ √ √ √ √ √ √

√ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ D D

Common resident Endemic Common resident Common resident Status Common resident Endemic Common resident Common resident Common resident Native Native Introduced Introduced, 1998 Native Endemic Endemic Endemic Endemic Endemic Introduced, 1920 Endemic Endemic Endemic Endemic Introduced, 1970 Status

ireo Anole

aterthrush

oad

Common Dwarf Gecko White-lipped Frog American Bullfrog Pig Frog Common Siguana Anole Puerto Rican Crested Anole Emerald Yellow-Bearded Anole Common Grass Anole Barred T Cane Field Coqui Grass Coqui Whistling Frog Coqui Green Iguana English common name Black-whiskered V Black-whiskered Puerto Rican vireo Zenaida Dove Gray Kingbird English common name W Northern Puerto Rican Spindalis Black-faced Grassquit Thrush Red-legged Loggerhead Kingbird

Salamanquita Común Ranita de Labio Blanco Toro Rana Rana Cerdo Lagartijo Jardinero Sapo Marino Coquí Churrí Siguana Común Lagartijo Común Verde Lagartijo Amarilla Lagartijo Barba Lagartijo Manchado Coquí de las Hierbas Coquí Pitito Coquí Común Gallina de Palo Spanish common name

Julian Chiví Bien-te-veo Tórtola Cardosantera Pitirre Reina Mora Zorsal de Patas Coloradas Clérigo Spanish common name Pizpita de Mangle Gorrión Negro

Grant Reinhardt & Lütken

Schmidt

Thomas d’Orbigny

Gmelin

olepis Günther

emminck

L. Amphibians and reptiles surveyed in the forests. D = Dorado forest, P = Patillas forest. H1 Humacao primary forest, H2 secondary Amphibians and reptiles surveyed in the forests. D = Dorado forest, P

dus plumbeus L. eo altiloquus Vieillot eo latimeri Baird Sphaerodactylus macr Sphaerodactylus Leptodactylus albilabris Günther Rana catesbeiana Shaw Rana grylio Stejneger Anolis evermanni Stejneger Annolis stratulus Cope antillensis Eleutherodactylus brittoni Eleutherodactylus cochranae Eleutherodactylus coqui Eleutherodactylus Iguana iguana L. Anolis cristatellus Duméril & Bibron Anolis gunladchi Peters Anolis pulchellus Duméril & Bibron Bufo marinus L. Ameiva exsul Cope forest. Scientific name Table 3. Table Vir Zenaida aurita T Vir Tyrannus dominicensis Tyrannus Table 2, continued. Table Scientific name bicolor Tiaris Tur caudifasciatus Tyrannus Seiurus motacilla Gmelin Spindalis portoricensis Bryant 11 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez

We found relatively few invertebrates overall. Our sampling methods were restricted to two types of hanging traps and a single type of land trap, and thus the survey did not capture the full range of insect niche habitats; for example we did not sample habitats within decaying plant materials. Moreover, both flying and crawl- ing insects were subject to frequent precipitation events and flooding of the forest floor. On one of our sampling dates, our results were affected by flooding of the traps themselves, though that effort was repeated on a subsequent date. For these reasons, we present here the list of organisms found in our surveys but we did not include them into our calculations of Shannon’s diversity index, nor in our further discussion of the forests. We found 15 species of insects, 6 species of arachnids, 2 species of myriapods, 2 species of mollusks, 3 species of crustaceans, and 2 additional animals (Table 4). All forests had nearly the same number of insect species—Dorado had 8, Patillas had 6, H1 had 8, and H2 had 7. We detected mollusks only at Dorado and Patil- las. Patillas had the most crustaceans, and H2 had the least. In terms of additional animals, only H1 had fish, probably because this section of forest receives direct freshwater inflow from a nearby creek. Among all forests, we found 56 species of plants and 6 species of fungi (Table 5). Dorado had 47 plant species, Patillas had 16, and Humacao had only 6. H1 had the largest trees, followed by Patillas; Dorado and H2 had much smaller trees (Fig. 5a). The canopy cover percentage was similar among all forests, except

Figure 5. (a) Average DBH, (b) canopy coverage percentage, (c) understory coverage percentage and coverage of Pterocarpus officinalis roots for Dorado, Patillas, Humacao 1 and Humacao 2. 12 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez

√ √ √ √ √ √ √ √ H2

√ √ √ √ √ √ √ √ H1

P √ √ √ √ √ √ √ √ √ √ √

√ √ √ √ √ √ √ √ √ √ √ √ D

Trap-Jaw Ant Trap-Jaw

ood Termite ood English common name Ant / Fiercely Biting Black Assassin Bug Thread-legged Southern Mole Cricket Loud-singing Bush Cricket Planthopper W Dry Assassin Bug Africanized Honey Bee Domestic Honeybee, Love Bug, Pyrrhocorid Bug Caterpillar of Gold Rim Swallowtail Bug, not identified further True Bug, not identified further True Bug, not identified further True Stretch Spider Rasping Nipple Snail Banded Caracol Fiddler Crab Blue Land Crab Mangrove Land Crab

veja Africanizada veja

iolinista

opo Spanish common name Berraco / Hormiga Chinche Depredador T Grillo Arbusto Grillo de Salta Hojas / Plantas Comején Chinche Depredador A Abeja Doméstica, Bomberitos Oruga de Mariposa Papilio Insecto, no identificados mas Insecto, no identificados mas Escarabajo Rojo Araña Extensa Caracol Áspero o Raspado Caracol de Bandas V Cangrejo Juey Común Juey Pelú Zambuco

groth

Latreille

sp. Giglio-Tos

L. eae L.

sp. sp . ermitoidae sp.

sp Battus polydamas L. Table 4. Invertebrates and other animals surveyed in the forests. D = Dorado forest, P = Patillas forest. H1 = Humacao primary forest, H2 = Humacao = Patillas forest. H1 Humacao primary forest, H2 4. Invertebrates and other animals surveyed in the forests. D = Dorado forest, P Table secondary forest. Scientific name Odontomachus haematodus L. Scapteriscus borellii T Family Apis andr Dysdercus Order Hemiptera Order Hemiptera Order Hemiptera Caracullus marginella Crustaceans Uca leptodactyla Rathbun Ucides cordatus Insects Subfamily Emesinae Orocharis Superfamily Fulgoroidea Doldina interjungens Ber Tetragnatha Mollusks Polydontes lima Férussac guanhumi Cardisoma

13 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez

√ √ √ √ H2

√ √ √ √ √ H1

P √ √ √ √ √ √ √

√ √ √ √ √ √ √ D

English common name Daddy-longlegs / Cellar spider Spider Wolf Harvestmen Jumping Spider Flat Spider Orchard Spider Scorpion Centipede Millipede Fish, not identified further Earthworm

ierra

ejedora

Spanish common name Araña de Patas Largas Araña Lobo Opilión Araña Saltadora Araña Plana T Araña Escorpión Cienpiés Milpiés Pez, no identificado T Lombriz de

sp. Simon

sp . Table 4, continued. Table Scientific name sp. Family Lycosidae Order Opiliones sp. Corythalia banski Roewer Arachnids Family Pholcidae sp. Selenops insularis Keyserling Family Buthidae Myriapods Scolopendra alternans Leach Leucauge regnyi Leucauge regnyi Family Julidae sp . Other animals present Actinopterygii sp. Class Estherella

14 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez

√ √ √ H

P √ √ √ √ √ √

√ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ D

Native Introduced Native Native Native Native Native Native Native Native Native Status Native Native Native Native Native Native Native Native Native Native Introduced Native

ree

Tree

ild Coffee

ood oe

Tongue Ficus Scalloped Lace Leaf Ardicea Ardisia Shoe Button W Gregory False Coffee Banyan Wild Jagua Black Mampoo Antilles Lacebark Strawberry Wild T Stinking Sacky Sac Bean Lauracea

English common name Golden Leather Fern T Cabbage-bark Apple Pond Apple Family Custard Gumbo Limbo Santa-Maria W Guyanese Crack Open Wild-mamee Tie Matchwood Malabar Plum Christmas Cherry Fabaceae Golden Flamboyant

aca

Desconocida V Lengua de Ardicia spp Mameyuelo Ucar Cafecillo Jagüey Blanco Ficus Jagua Corcho Bromelia Cactus Pitahaya Algarrobo Guama Lauracea Spanish common name Helecho de Mangle Moca Cayur Annonaceae Almacigo María Palo Blanco Laurel Espada Cupey Uva de Sierra Macho Yagrumo Pomarrosa Guayaba Silvestre Fabaceae Amarillo Flamboyan

Rich.

(DC.) Backer ex K. Heyne (Aubl.) Maguire, Steyerm. & Frodin

Mez Sarg.

w. (Haw.) Saff. (Haw.) . Wright

. S

. .) Willd Wright L.

Jacq . enatum Kunth

. .

. sp . ostichum aureum L. ostichum aureum

dicea disia elliptica Thunb. Anthurium cr Ar Bucida buceras (L.) Ficus citrifolia Mill Ficus sp Genipa americana L Guapira fragrans (Dum. Cours.) Little antillana Hohenbergia trigonus Hylocereus Hymenaea courbaril L. Inga laurina (Sw Lauracea sp Ar Faramea occidentalis (L.) A. Table 5. Plants and fungi surveyed in the forests. D = Dorado forest, P = Patillas forest. H Humacao 5. Plants and fungi surveyed in the forests. D = Dorado forest, P Table Scientific name Annona glabra Anonacea Bursera simaruba (L.) Calophyllum calaba Britton Casearia guianensis (Aubl.) Urb. Casearia sylvestris Clusia rosea Coccoloba diversifolia Jacq Didymopanax morototoni Eugenia jambos (L.) Alston Eugenia pseudopsidium Jacq Fabaceae sp. # 1 Peltophorum pterocarpum Plants Acr Andira inermis

15 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez

√ √ √ √ √ H

P √ √ √ √ √ √ √ √ √

√ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ D

Status Native Native Native Introduced Introduced Native Native Native Native Native Native Native Native Native Native Native Native Native

ree

ithe ood

Lumpy Bracket Magic Mushrooms Artist's Conk Phellinus Fungus

English common name Puerto Rico Cinnamon W Bullet False Mastic Indian Mulberry Black Mulberry Peronia Bread and Cheese Golden Serpent Fern Rough-leaved Pepper Almond Sweet Whisk Fern Palo de Cachimbo T Dragon Bloodwood White Indigo Berry Royal Palm White Cedar Airplant Giant W Green Green Parasol Red Cup Fungus

erde

ainilla

Amarillo

Yesquero Blanco Yesquero Hongos Mágicos Oreja de Palo Yesca

Spanish common name Canelilla Ausubo Tortugo Noni Moral Palo de Matos Bejuco de Costilla Helecho Espada Higuillo de Limón Almendro Helecho Escoba Palo de Cachimbo Palo de Pollo Tintillo Palma Real Roble Blanco Bromelia V Orquidea V Hongo Sombrilla Copitas

Chev

Jacq .

Webb (G. Mey.) Massee (G. Mey.) . Cook

. Jacq. w. . Beauv

(L.) J. Sm.

(L.) Quél. . (W.Wright) Sw. (W.Wright)

ophylla (DC.) Britton

Trametes gibbosa Trametes Psilocybe sp Ganoderma applanatum (Pers.) Pat. Phellinus igniarius Table 5, continued. Table Scientific name Licaria parvifolia (Lam.) Kosterm. Manilkara bidentata (A.DC.) A. foetidissimum Mastichodendron Morinda citrifolia L. Morus nigra L Ormosia krugii Urb. Paullinia pinnata L Phlebodium aureum Piper amalago L Prunus dulcis (Mill.) D.A. Psilotum nudum (L.) P Psychotria brachiate S officinalis Pterocarpus Randia aculeate L. Roystonea borinquena O.F heter Tabebuia fasciculate Sw Tillandsia Unknown # 1 Unknown # 2 Unknown # 3 Unknown # 4 claviculata Vanilla Fungi molybdites Chlorophyllum Cookeina tricholoma (Mont.) Kountze

16 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez H2, where cover values were lower (Fig. 5b). Understory cover was highest at Do- rado and lowest at H2. Patillas had the most visible root coverage on the ground surface (Fig. 5c). In summary, Dorado had the highest faunal abundance (48 organisms, excluding invertebrates) and the highest faunal Shannon’s diversity value (H' = 3.40 [excluding invertebrates]; Table 6). Dorado had the greatest number of native or endemic species—birds, 7; amphibians/reptiles, 12; and plants, 43. However, Dorado also had the most invasive or exotic bird and plant species, 3 and 4, respectively. For plants and fungi, Dorado had the highest plant and fungal diversity (H' = 2.87). Patillas was second in richness for both fauna (H' = 2.89) and plants/fungi (H' = 1.27). H2 was the least rich in fauna (11 organisms, excluding invertebrates) and least diverse (H' = 1.56). Humacao had the most invasive amphibian/reptile species, 4. All of the plants in both Patillas and Humacao were native or endemic.

Soil, land cover, and environmental factors The Dorado area has an average temperature of 25.1 °C (77.2 °F), a mean annual maximum temperature of 28.3 °C (83.0 °F), and a mean annual minimum

Table 6. Shannon’s diversity index values for each forest. H1 = Humacao primary forest, H2 = Hu- macao secondary forest.

Dorado Patillas H 1 H 2 Birds 3.08 2.40 1.94 2.21 Amphibians and reptiles 2.14 2.00 1.85 1.89 Fauna (excluding invertebrates) 3.40 2.89 2.59 1.56 Plants and fungi 2.88 1.27 0.73

Table 7. Temperature and precipitation averages for the forests from 1980 to 2010.

Rainfall Avg min temp Average temp Avg max temp Forest (station)/period mm (in) °C (°F) °C (°F) °C (°F) Dorado (Dorado 2 WnW PR US) Annual 1637.0 (64.5) 21.3 (70.4) 25.1 (77.2) 28.3 (83.9) Winter (DJF) 388.4 (15.3) 19.4 (67) 24.1 (73.5) 26.6 (80) Spring (MAM) 349.8 (13.8) 20.7 (69.4) 24.7 (76.6) 28.7 (83.7) Summer (JJA) 404.9 (15.9) 22.8 (73.1) 26.6 (79.9) 30.4 (86.8) Fall (SON) 494.0 (19.5) 22.2 (71.9) 25.8 (78.6) 29.5 (85.2) Patillas (Guayama 2 E PR US) Annual 1386.1 (54.6) 23.5 (74.4) 27.1 (80.9) 30.7 (87.4) Winter (DJF) 182.9 (7.2) 22.2 (72) 25.9 (78.7) 29.6 (85.4) Spring (MAM) 247.9 (9.7) 23.1 (73.5) 26.7 (80.1) 30.3 (86.6) Summer (JJA) 421.1(16.6) 24.8 (76.7) 28.3 (83) 31.7 (89.2) Fall (SON) 534.2 (21.0) 24.1 (75.3) 27.7 (81.9) 31.3 (88.4) Humacao (Roosevelt Roads) Annual 1329.4 (52.3) 23.8 (75) 27.1 (80.8) 30.2 (86.5) Winter (DJF) 242.1 (9.5) 22.3 (72.2) 25.5 (78) 28.7 (83.7) Spring (MAM) 281.4 (11.1) 23.4 (74.1) 26.6 (79.9) 29.7 (85.6) Summer (JJA) 333.0 (13.1) 25.4 (77.8) 28.5 (83.3) 31.5 (88.8) Fall (SON) 472.9 (18.6) 24.4 (75.9) 27.6 (81.8) 31.0 (87.8)

17 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez temperature of 21.3 °C (70.4 °F) (Table 7). The average annual precipitation is 1637.0 mm (64.5 in). At Patillas, the average temperature is 27.1 °C (80.9 °F), the mean annual maximum temperature is 30.7 °C (87.3 °F), and the mean annual minimum temperature is 23.5 °C (74.3 °F). On average, Patillas receives 1386.1 mm (54.6 in) of precipitation annually. The average temperature for the Humacao area is 27.1 °C (80.8°F), with a mean annual maximum temperature of 30.2 °C (86.4 °F) and a mean annual minimum temperature of 23.8 °C (74.3 °F); Average annual precipitation is 1329.4 mm (52.3 in). For the soil samples, we present here only nitrate, percent organic matter, soluble salts, sulfur, and calcium. Nitrate was highest in the Dorado samples, but

Figure 6. Soil components for Dorado, Patillas, Humacao 1 and Humacao 2 forest: (a) nitrate, (b) organic matter %, (c) soluble salts, (d) sulfur, and (e) calcium. 18 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez was low in those from Patillas, H1, and H2 (Fig. 6a). Organic matter values were lowest in samples from H1 followed by H2; higher values were recorded for the Patillas and Dorado soils (Fig. 6b). Soluble salts were highest at H2, but low in H1 and Dorado (Fig. 6c). Sulfur values were highest in H2 soils; Dorado and H1 had the lowest values (Fig. 6d). Calcium was the lowest in Dorado, H1, and H2; the highest value was recorded at Patillas (Fig. 6e). The Dorado forest (Fig. 7a) is located within lands owned by the Dorado Beach Hotel Corporation, which is a luxury resort community. To the north of the Ptero- carpus forest, there is an additional non-Pterocarpus forested area that is managed by the Puerto Rico Conservation Trust. To the east, the Dorado forest is separated from a large area of urban development by only a small patch of trees. A remaining small patch of forest adjacent to another well-developed urban area lies to the south, and there is a large golf course to the west. The Patillas forest (Fig. 7b) occurs within the Punta Viento Natural Reserve. A large pasture abuts the forest on the north and mangrove forests occur to the east, south, and west. The Humacao forest (Fig. 7c) is the only one of the forests we sampled that has direct connections to open water through channels or lagoons connected to the ocean. Agricultural lands are adjacent to the northern part of the forest. Urban areas are immediately across the lagoon, to the southwest. The Dorado forest was the closest to roads, houses, human-managed ecosystems, and the ocean (Table 8). In contrast, H1 had the greatest distances to roads,

Figure 7. Land-use/land-cover maps, for (a) Dorado, (b), Patillas, and (c) Humacao. 19 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez houses, and the ocean. Patillas was the closest to an agricultural area, and H2 was the farthest from an agricultural area.

Discussion Richness and diversity among the forests, and possible causes for differences Of the forests we sampled, the Dorado Pterocarpus forest is the most rich and diverse in terms of organisms and has the greatest number of native and endemic species, while the Humacao Pterocarpus forest is the least rich and diverse. How- ever, Dorado is the smallest forest, covering only 2.4 ha, while Humacao is the largest, with an area of 150 ha, which comprises 63% of the total Pterocarpus coverage in Puerto Rico. The temperature and precipitation differences among the forests do not likely explain the difference in richness or diversity. The average annual precipitation is 1637.0 mm (64.5 in) in Dorado Forest and 1329.4 mm (52.3 in) in Humacoa, a difference of only ≈1/5 the total (NOAA 2013). The average temperatures are 25.1 °C (77.1 °F) and 27.1 °C (80.8 °F) for Dorado and Humacao, respectively, a difference of only 2 °C (3.7 °F) (Table 7; NOAA 2013). One potential explanation for the differences in species richness and diversity can be found in results of our soil sampling. Dorado soil samples were high in nitrate, a component of many commercial fertilizers. It is also produced by fixation of nitrogen by soil bacteria as part of the nitrogen cycle, as well as through the decay of organic matter in the soil. The relatively high level of nitrate may be due, in part, to inputs from human activity: Dorado is surrounded by human-managed areas, including a golf course and urban areas. Dorado soils also had the highest organic matter percentage, likely because of the large amount of plant material deposited due to high understory cover and low overstory canopy cover. In contrast, H1 has soils with nitrate below detectable limits, and low impact from human disturbance. The mature trees in H1 have the largest average dbh and, due to the large dense canopy, there is low understory coverage and a low amount of organic matter. Ad- ditionally, the low organic matter in H1 forest soils could be explained by inflow that washes the material downstream during frequent rain events. Inflow and water sources may also be factors that alter richness and diversity. The amount of soluble salts and sulfur in the forests’ soils are likely related to saltwater intrusion, as they were highest at the H2 forest, followed by the Patillas forest. Hydrogen sulfide often results from anaerobic digestion or reduction, the

Table 8. Distance of forest to selected features.

Distance (m) Features Dorado Patillas H 1 H 2 Road 173.43 542.19 1455.42 734.58 House 107.57 640.61 1253.19 723.00 Agricultural area 1764.99 620.92 1443.95 2509.16 Ocean 477.77 495.61 2514.75 1106.54 Human managed 118.62 578.52 1170.34 1326.03

20 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez bacterial breakdown of organic matter in the absence of oxygen, which commonly occurs in swamps. The subsequent oxidation of hydrogen sulfide produces sulfur. Interestingly, Patillas soils had the highest calcium levels, reaching almost 4000 ppm. Patillas differs from the other sites because spring water enters the forested wetland’s surface waters from underlying karst limestone through the Pozo Encan- tado or Enchanted Well. The most evident factor influencing richness and diversity among the forests is the adjacent land-use history of the sites. As mentioned earlier, the Dorado forest is the smallest as well as the most fragmented one, in terms of its interspersion with other land-cover types. Dorado also has the highest number of endemic and native plant species, as well as invasive plant species. Increased plant diversity provides increased animal habitat, and explains, in part, the higher richness of fauna. The forest’s perimeter-to-area ratio is high and it is surrounded by urban homes, infra- structure, and a golf course. Patillas is the second smallest forest, but it is entirely enclosed within a natural reserve. It consistently ranks in the middle of the three forests sampled, in terms of richness and diversity, proximity to human disturbance, and average dbh. It also has the highest Pterocarpus root-cover percentage, likely because it is drier than Huma- cao, though it is still influenced to a small degree by salt, rain, and spring water. H1 is the best example of a large, mature, historically undisturbed, primary Ptero- carpus forest in Puerto Rico. Its trees have a large dbh and canopy coverage, and its soils are low in nutrients, organic matter, and have limited saltwater influence. H2 is the youngest forest of the sites we sampled, and is composed of secondary re-growth established in the 1950s. It has the lowest dbh and overstory canopy cover among all of our study sites. It is strongly affected by saltwater intrusion, with channels crossing it that connect directly to the ocean. It is also necessary to mention that our methodology excluded some habitats where we likely would have recorded additional species. For example, we would undoubtedly have detected additional invertebrates utilizing habitat niches such as dead wood, live tree interiors, and the upper canopy of the forest.

Primary versus secondary Pterocarpus forests At Humacao, the primary and secondary forests have been exposed to different human disturbances. Humans have altered the water flowing into the forests in both sections of forest, though the primary forest has been more affected by altered upstream inflow through digging of irrigation channels for sugarcane production. The secondary forest, while also affected by changes in water flow, was cut and cleared in the 1950s. Subsequently, abandonment of this section resulted in re-growth. In 2000, the US Army Corps of Engineers attempted to reduce flooding in the nearby urban community of Punta Santiago, and their creation of a canal introduced saltwater to the Humacao secondary forest. The number of bird, amphibian and reptile species is lower in the primary forest (total 21) than the secondary forest (total 30). Moreover, the soil in the primary forest had the lowest organic matter values and low nutrient values, including nitrate, while also showing signs of saltwater inundation.

21 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez Our results suggest that mature Pterocarpus officinalis-dominated forests are largely vegetatively monospecific (as also found by Alvarez-López 1990), low in number of dependent species, and have nutrient-poor soils. The fragmentation of these forests, alteration of hydrology, and conversion of adjacent environments has only increased their floristic and faunal diversity.

Conclusion Human influences on these forests have been significant across Puerto Rico and the Caribbean region. Our analysis points out that fragmentation and changes in the surrounding land used by humans increased both richness and diversity in these forests. This increase in the diversity of species comes from both native and endemic Puerto Rican species that have become established in the fragmented forest and small remnants, but also from exotic and invasive species. Still, all Pterocarpus forests provide a natural environment to sustain organisms, and there are likely organisms that thrive particularly in conjunction with Pterocar- pus. For example, although we did not identify any species endemic to Pterocarpus forests, we did find small, as yet unidentified fish in only the most undisturbed -por tions of the primary forest in Humacao. Because the remaining areas covered by the Pterocarpus forest are so limited in extent, protection and management of this forest type are necessary. Ptero- carpus forests are known to support a number of native and endemic species (Cintrón 1983), specifically amphibians, which are reported to be imperiled worldwide. Our results should be useful to those who manage areas that support Pterocarpus forests, not only in a broad sense, but also more specifically to the managers of the forests included in this research. This work will assist those who manage this limited resource in the context of ongoing sea level rise, climate change, nutrient pollution, human interaction, upstream hydrological modifications, and deforestation. We suggest that future management should focus on two distinct preservation efforts. Maintenance of high diversity and use of beneficial habitat should be the goals for Dorado and Patillas, the smaller forests. One problem with this strategy is that Pterocarpus trees may not be able to replace themselves over multiple genera- tions, as other flora may be able to outcompetePterocarpus seedlings in areas with lower amounts of upper canopy cover and higher sun exposure, particularly con- sidering the low number of trees from which to recruit propagules. If management is undertaken to favor Pterocarpus growth, this might negatively affect several species of concern present at the site. Whether these forests will eventually lose their Pterocarpus trees or revert back to a forest with more complete Pterocarpus dominance is unknown, but future studies on tree age structure and recruitment suc- cess could help to answer this question. Conversely, for the remaining large forest (Humacao), the maintenance of low diversity as a semblance of the Pre-Columbian state should be the goal because this forest is the remaining exemplar of the natural state of the Pterocarpus forest ecosystem in Puerto Rico.

22 2013 Caribbean Naturalist No. 4 R.A. Feagin, F. Toledo-Rodríguez, R.J. Colón-Rivera, F. Smeins, and R. Lopez

Acknowledgments This research was funded in part by the Hispanic Leaders in Agriculture and the Envi- ronment Fellowship Program, and the College of Agriculture and Life Sciences at Texas A&M University. We would like to thank Dr. Manuel Piña and Dr. Dave Reed for mentor- ship and support. We would like to thank Doel Delgado for his photography skills. This research would not have been possible without the assistance of Ana Pagan, Luis Baergas, Maño Corbet, Cynthia Morales Otero, Omar Monzon Carmona, Frank Cosme Arroyo, Ray Rodriguez Colon, Noel Rivera Gómez, Carlos Zayas, Alejandro Maldonado, Natalia López- Figueroa, and Denny Fernández del Viso.

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