Comprehensive analysis of land morphology is essential to supporting a wide range environmental studies. We developed a landforms model that identifies eleven landform units for Puerto Rico based on parameters of land position and slope. The model is capable of extracting operational information in a simple way and is adaptable to different environments and objectives. The implementation of the landforms model for land cover change analysis represents an advanced step towards understanding the expansion of urban areas and forest cover in Puerto Rico between 1977 and 1994. Expansion of urban areas has typically been associated with low and flat topographies. Forest recovery, on the other hand, has been associated with high elevations and steep slopes. Our study revealed that (1) nearly half of new developments occurred outside the plains, (2) almost all new forests occurred in mountain regions (but not on the steepest slopes), and (3) there are transitional and very dynamic landforms (the side slopes) that experience both important land development and forest recovery. Finally, we present additional examples of the land-forms model applications, including vegetation mapping, physiography, and the modeling of vertebrate habitat distributions.

A study was conducted on the industrial area waters of Guayanilla Bay to determine the potential for microbial utilization of toxic compounds such as fluorene, naphthalene, phenanthrene, phenol and pentachlorophenol (PCP) as a sole carbon source. Utilization of toxic substrates was determined by using Biolog MT Microplates inoculated with environmental samples. Water quality variables such as pH, salinity, temperature and turbidity were also measured. In general, temporal changes in the Bay influenced the utilization of these compounds, with increased utilization of toxic compounds during rainy season. Heavy rainfall caused perturbation of sediments rich in organic matter, as was evidenced by increased turbidities. This provided both the environment and the substrates necessary for enhanced microbial growth and activity. The levels of dissolved oxygen in the bay water decreased as a result of increased biological activity. Other environmental factors such as fluctuations in temperature, salinity, and pH appear to have little or no impact on microbial utilization of toxic compounds in the bay water.

Total (live dead) ostacod assemblages are documented in five samples from the Coconut Field area, and eight from the Mahogany Field, SE of Trinidad and east of the Orinoco delta. Although the fields both lie in ∼70–80m of water, and Mahogany lies only 18 km NE of Coconut, they are situated in different biofacies: Bradleya ex gr. dictyon, the dominant species in the Coconut Field (46% of total recovery), forms only 7.6% of the fauna in the Mahogany Field. Assemblages in the Mahogany Field are dominated by Bairdoppilata dorsoangulata. Diversity (measured using both species richness and the Information Function) is greater at the Mahogany Field. This suggests greater water clarity at the Mahogany Field, which lies farther from the Orinoco delta. Bythoceratina carmoi, Callistocythere fossulata and Bairdoppilata dorsoangulata are recorded north of 4°N for the first time.

The extant original material that Agustín Stahl used for describing five new species in his Estudios sobre (para) la flora de Puerto Rico was studied. Lectotypes are designated for Hibiscus tomentosus Stahl, Marialva elliptica Stahl, Byrsonima portoricensis Stahl, and Clusia gundlachii Stahl. His known extant plant collections are cited in an appendix with reference to the herbaria where they are deposited.

We studied gas exchange, leaf dimensions, litter production, leaf and litterfall chemistry, nutrient flux to the forest floor, retranslocation rates, and nutrient use efficiency of mangroves in Jobos Bay, Puerto Rico. The fringe forest had a salinity gradient from the ocean (35‰) to a salt flat (100‰) and a basin (about 80‰). Red (Rhizophora mangle), white (Laguncularia racemosa), and black (Avicennia germinans) mangroves were zoned along this gradient. Photosynthetic rates, stomatal conductance, leaf area and weight, leaf specific area, and nutrient use efficiency decreased with increasing salinity, while xylem tension, nutrient retranslocation, and leaf respiration increased with increasing salinity. The concentration of some leaf elements increased with salinity (N, P, Mg, Na) while others decreased (Ca). Leaf specific area was less variable than leaf area or weight. Maximum photosynthesis (12.7 µmol CO₂ m^-2s^-1), leaf conductance (283 mmol CO₂ m^-2s^-1), and litterfall (16.9 Mg ha^-1 yr^-1) in the fringe were high in comparison with those of other world mangroves. Nutrient flux to the forest floor was also high and nutrient use efficiency was low in this forest. Part of the reason for these high values and low use-efficiencies was the high proportion of nutrient-rich flowers and propagules in litterfall. Nevertheless, access to freshwater in the form of groundwater discharge and about 1 m of annual rainfall play a role in the high productivity of the Jobos mangroves.

Neotropical Plecoptera represent an interesting subject of study, for their phylogenetic, biogeographical and ecological importance. The Plecopterofauna of a large portion of the Neotropics is represented by only one genus of Perlidae, Anacroneuria Klapálek. This work provides information about the stonefly fauna of Nicaragua, a country for which few previous investigations have been undertaken for this insect group. Eight species of Anacroneuria are currently recorded, including A. curiosa Stark, A. holzenthali Stark, A. planicollis Klapálek, A. starki Fenoglio & Morisi, A. talamanca Stark, A. litura (Pictet), and the two new records: A. divisa (Navas), and A. lineata (Navas). In addition, a key for adult males is provided and the putative nymph of A. talamanca is described.

Analyses of sediment cores and surface samples collected in Coral Bay, St. John, USVI, reveal four sedimentary facies. The bottom three reflect the natural transgressive evolution of the bay during the Holocene sea-level rise. The surficial facies represents a dramatic increase in terrigenous sediment input since the 1950's. This surficial layer is defined by a decrease in grain size, increase in organic content, increase in terrigenous constituents, and subtle decrease in calcium carbonate content compared to underlying sediments. Based upon ²¹⁰Pb and ¹⁴C dating, accumulation rates have increased by roughly one order-of--magnitude since the 1950's as a result of this increase in terrigenous sediment input. The surficial sediment layer likely represents an anthropogenic signal reflecting the dramatic increase in island development over the past few decades. The surficial “impacted” layer is most pronounced (i.e., exhibits the greatest deviation from underlying sediments) adjacent to the most heavily developed areas, and in protected, low energy regions. It becomes less pronounced in the more open and seaward portions of the bay. This pattern suggests proximity to input and energy level are the dominant controls governing where terrigenous sediments ultimately accumulate. Comparisons with anthropogenically-impacted estuaries along the U.S. Atlantic and Gulf coasts show that, although there are substantial differences in scale and watershed character, all have experienced recent dramatic increases in sediment accumulation. Unlike Coral Bay, however, there is no anthropogenic signal in sediment texture and composition. This may be a reflection of St. John's high-relief terrain, high erodibility of rocks/soils, and intense weathering associated with tropical volcanic island settings.

In general, faunal diversity increases with forest age; therefore, we predict that ant species richness in secondary forests will increase during succession and species composition will vary among different stages of succession. To test this hypothesis we describe the ant communities from five chronosequences comprised of forests that varied in the time lapsed since abandonment (i.e. 0-5 yr, 25–35 yr, and >60 yr). In each site, ants were sampled using baited traps, pitfall traps, and litter sampling. Ants were identified to species and species abundance per sample was recorded. A total of 21 ant species were collected. In all chronosequences, the 25–35 yr secondary forests had the highest ant richness. During this stage of succession, these forests have resources and microhabitats representative of both early successional forest (0–5 yr) and older successional forest (>60 yr). Thus, the ant species composition included both open-habitat and forest ant species. However, the overall composition of the 25–35 yr secondary forests displayed greater similarity to the composition of the >60 yr secondary forests. Similar results were obtained when we included two additional chronosequences and limited the analysis to litter ants. These results suggest that site age is a major force driving ant diversity and composition during plant secondary succession in Puerto Rico.

The columnar cacti Stenocereus griseus and Subpilocereus repandus in the semi-arid enclave of Lagunillas produce a large biomass of fleshy fruits consumed by both birds and bats. In this paper we quantify the consumption of fruits of both cacti by birds and bats. For two weeks during the fructification periods of S. griseus and C. repandus ripe fruits were offered to birds during the day and to bats at night. Bats consumed larger amount of C. repandus pulp than birds, while the consumption of S. griseus was the same for both groups. Birds consumed more S. griseus than C. repandus fruits, whereas bats consumed the fruits of both cacti species in equal amounts. We believe that the different results are due to the morphological characteristics of these fruits; C. repandus has fruits with cryptic coloring that makes their detection difficult for flying frugivores with color vision, while S. griseus has red fruits, which makes them conspicuous to avian frugivores. An ancillary preference study supports this notion, as birds were more likely to consume red-colored morphs of S. griseus compared to white-colored morphs. On the other hand, bats do not distinguish colors and consume both cacti species in equal amounts. This suggests that S. griseus, at least, presents an intermediate bird-bat dispersion syndrome, which, in principle, would guarantee greater fitness in comparison to C. repandus.

Florida presently has a large number (44) of established non-native amphibians and reptiles, 36 of which are lizards. There are currently one native and four non-native teiid lizards in Florida, and difficulty arises when trying to distinguish them from other similar species, especially in small individuals and/or deteriorated or faded preserved specimens. Because of the potential for their misidentifications in both the field and laboratory, we present a key to the established teiid species in Florida along with their current geographic distributions.

Monitoring glucocorticoids is commonly used to evaluate heightened physiological demands on a population under varying conditions. However, detecting changes depends on knowing baseline and temporal patterns in glucocorticoids. Plasma corticosterone was measured in the Turks and Caicos iguana (Cyclura carinata carinata) to determine diurnal and bi-annual baseline patterns as part of monitoring associated with a large-scale translocation program. Plasma from wild males (N = 100) and females (N = 96) was obtained in January of 2002 and 2003 and June 2002. Glucocorticoid concentrations were determined by radioimmunoassay (RIA). Glucocorticoid levels were significantly greater in females than males, and showed a tendency to be inversely related to body condition in females but not in males. For the January samples, there was a non-significant trend for glucocorticoid levels to be highest in the morning. Establishing a daily pattern for only the hours the animals are above ground is useful for evaluating subsequent field studies. The potential influence of reproductive state and seasonal rainfall patterns on glucocorticoid levels is discussed.

The first occurrence of crocodylians from the Quaternary of mainland Puerto Rico is reported from a cave in northern Puerto Rico: this record expands the distribution of crocodylians eastward in the Caribbean region during this period. The occurrence of crocodylians in the Quaternary of Puerto Rico adds another taxon to the current list of extinct fauna of the island. The collection location of four mammalian species, four reptiles, and two amphibians, is also shown on the first published map of this site, called Cueva Salida (Exit Cave). The fossil assemblage supports both previous interpretation of more xeric conditions in the area and a probable Quaternary age for this deposit.

The acute toxicity of endosulfan to three freshwater snails, Melanoides tuberculata (Muller, 1774), Thiara granifera (Lamarck, 1822) and Planorbella duryi (Weatherby, 1879), was determined in Jamaica. These three species are exotic to the island. The 24 hr LC₅₀ values were 7.74, 5.35 and 4.26 mgL^-1, respectively. The 96 hr LC₅₀ values were 2.30, 1.74 and 1.35 mgL^-1, respectively. The three species displayed avoidance reactions, which may have contributed to their higher tolerance of endosulfan in comparison to other aquatic invertebrates and fishes.

Mr. H. L. ‘Hal’ Dixon (1941–2005) was an expert on Jamaican fossil echinoids who contributed to many publications on the Cretaceous and, mainly, Cenozoic geology and paleontology of the island. His research on the Upper Oligocene echinoderms of Jamaica was a particularly comprehensive study of fossils from an intractable limestone. His contribution to the research programs of other experts led to advancement in our knowledge of the Jamaican fossil record on a broad front, including such groups as decapod crustaceans (crabs), trace fossils, rudist bivalves and sirenians (sea cows).

We report an observation of an orbweaving spider (Argiope savignyi; Araneidae) capturing and feeding on a proboscis bat (Rhynchonycteris naso; Emballonuridae) at the La Selva Biological Station in the Caribbean lowlands of Costa Rica. This observation and others suggest that spiders prey upon small bats more frequently than has been noted previously, and that invertebrates should now be considered as regular predators on small bats.