Byron S. Wilson

Plant Species Discrimination in a Tropical Wetland Using In Situ Hyperspectral Data

We investigated the use of full-range (400–2,500 nm) hyperspectral data obtained by sampling foliar reflectances to discriminate 46 plant species in a tropical wetland in Jamaica. A total of 47 spectral variables, including derivative spectra, spectral vegetation indices, spectral position variables, normalized spectra and spectral absorption features, were used for classifying the 46 species. The Mann–Whitney U-test, paired one-way ANOVA, principal component analysis (PCA), random forest (RF) and a wrapper approach with a support vector machine were used as feature selection methods. Linear discriminant analysis (LDA), an artificial neural network (ANN) and a generalized linear model fitted with elastic net penalties (GLMnet) were then used for species separation. For comparison, the RF classifier (denoted as RFa) was also used to separate the species by using all reflectance spectra and spectral indices, respectively, without applying any feature selection. The RFa classifier was able to achieve 91.8% and 84.8% accuracy with importance-ranked spectral indices and reflectance spectra, respectively. The GLMnet classifier produced the lowest overall accuracies for feature-selected reflectance spectra data (52–77%) when compared with the LDA and ANN methods. However, when feature-selected spectral indices were used, the GLMnet produced overall accuracies ranging from 79 to 88%, which were the highest among the three classifiers that used feature-selected data. A total of 12 species recorded a 100% producer accuracy, but with spectral indices, and an additional 8 species had perfect producer accuracies, regardless of the input features. The results of this study suggest that the GLMnet classifier can be used, particularly on feature-selected spectral indices, to discern vegetation in wetlands. However, it might be more efficient to use RFa without feature-selected variables, especially for spectral indices.

Conservation implications of small Indian mongoose (Herpestes auropunctatus) predation in a hotspot within a hotspot: the Hellshire Hills, Jamaica

This study documents impacts of the small Indian mongoose (Herpestes auropunctatus) on a threatened endemic fauna occurring in a biodiversity hotspot within a hotspot, the Hellshire Hills, Jamaica. We analyzed the stomach contents of 217 mongooses and supplemented this information with behavioural observations. The mongoose’s diet consists primarily of invertebrates and lizards, but bird feathers, mammal hair, and a small number of seeds were also recorded. Invertebrates and lizards accounted for 93% of identified prey items. Of special concern were the remains of threatened species such as the recently re-discovered blue-tailed galliwasp (Celestus duquesneyi), indicating that the mongoose may represent a considerable threat to this poorly known taxon. Dietary analyses did not reveal remains of the Critically Endangered Jamaican iguana (Cyclura collei), yet field observations confirmed that the mongoose is a potent predator of hatchling iguanas. Ignoring issues of sample size, this suggests that the analysis of stomach contents alone may mask important demographic impacts attributable to the mongoose (or other predator species). In other words, rare and endangered species may not be detected in diet samples, but the impact of predation may be of demographic significance for effected prey taxa. This study supports previous arguments concerning the negative impact of the mongoose on endemic insular species, and underscores the utility of employing field observations of mongoose foraging behaviour to provide important insights into the conservation implications of predation by non-native predators.

Comparing the effects of classification techniques on landscape-level assessments: pixel-based versus object-based classification

Landscape-level assessments, particularly the quantification of forest fragmentation, often involve calculating landscape metrics from classified remotely sensed images. The utility of these derived metrics is often assumed to be dependent on the quality of the classified images. We compared conventional, pixel-based classification and a newer method of object-based classification to determine the effects of these two methods on fragmentation analysis of Cockpit Country, Jamaica, West Indies. Both methods showed similar trends in fragmentation metrics; however, there were significant differences between the methods for the metrics that quantified landscape configuration. The object-based classification allowed for the easy inclusion of roads into the analysis, which produced more accurate maps that showed a significant difference in the size of the largest forest patch. The object-based method also allowed classification of forests to show the location and extent of core forest areas; we were therefore able to identify an area of core forest that had remained consistent over the study period as a significant area for conservation focus. We recommend that the object-based method be the method chosen for landscape analyses, particularly forest-fragmentation studies.

Continuous spermatogenesis and the germ cell development strategy within the testis of the Jamaican Gray Anole, Anolis lineatopus

Testicular tissues from Anolis lineatopus were examined histologically to determine testicular structure, germ cell morphologies, and the germ cell development strategy employed during spermatogenesis. Anoles (N=36) were collected from southern Jamaica from October 2004 to September 2005. Testes were extracted and fixed in Trumps fixative, dehydrated, embedded in Spurrs plastic, sectioned, and stained with basic fuchsin/toluidine blue. The testes of Jamaican Anoles were composed of seminiferous tubules lined with seminiferous epithelia, similar to birds and mammals, and were spermatogenically active during every month of the year. However, spermatogenic activity fluctuated based on morphometric data for February, May and June, and September-December. Sequential increases for these months and decreases in between months in tubular diameters and epithelial heights were due to fluctuations in number of elongating spermatids and spermiation events. Cellular associations were not observed during spermatogenesis in A. lineatopus, and three or more spermatids coincided with mitotic and meiotic cells within the seminiferous epithelium. Although the germ cell generations were layered within the seminiferous epithelium, similar to birds and mammals, the actual temporal development of germ cells and bursts of sperm release more closely resembled that reported recently for other reptilian taxa. All of these reptiles were temperate species that showed considerable seasonality in terms of testis morphology and spermatogenesis. The Jamaican Gray Anole has continuous spermatogenesis yet maintains this temporal germ cell development pattern. Thus, a lack of seasonal spermatogenesis in this anole seems to have no influence on the germ cell development strategy employed during sperm development.

Conservation Of Insular Herpetofaunas In The West Indies

There are approximately 700 species of amphibians and reptiles that have been described from the West Indies, here defined as excluding Trinidad and Tobago which are adjacent to South America and have continental faunas. This includes approximately 180 amphibians and 520 reptiles. The conservation status of only the amphibians has been assessed comprehensively, and 84% of those species are considered threatened. This chapter provides brief overview of the origin and evolution of the West Indian herpetofauna. This is followed by a discussion of two aspects vital to its conservation: stopping deforestation and facilitating systematic research. For some species, especially large reptiles, it has been claimed that introduced predators have had a greater negative impact than habitat alteration. Although this probably is true in some instances, the point made here is that habitat destruction-in particular, deforestation-is the major and primary threat to the survival of most species. Keywords:amphibians; deforestation; habitat alteration; reptiles; West Indian herpetofauna

Use of object-oriented classification and fragmentation analysis (1985–2008) to identify important areas for conservation in Cockpit Country, Jamaica

Forest fragmentation is one of the most important threats to global biodiversity, particularly in tropical developing countries. Identifying priority areas for conservation within these forests is essential to their effective management. However, this requires current, accurate environmental information that is often lacking in developing countries. The Cockpit Country, Jamaica, contains forests of international importance in terms of levels of endemism and overall diversity. These forests are under severe threat from the prospect of bauxite mining and other anthropogenic disturbances. In the absence of adequate, up-to-date ecological information, we used satellite remote sensing data and fragmentation analysis to identify interior forested areas that have experienced little or no change as priority conservation sites. We classified Landsat images from 1985, 1989, 1995, 2002, and 2008, using an object-oriented method, which allowed for the inclusion of roads. We conducted our fragmentation analysis using metrics to quantify changes in forest patch number, area, shape, and aggregation. Deforestation and fragmentation fluctuated within the 23-year period but were mostly confined to the periphery of the forest, close to roads and access trails. An area of core forest that remained intact over the period of study was identified within the largest forest patch, most of which was located within the boundaries of a forest reserve and included the last remaining patches of closed-broadleaf forest. These areas should be given highest priority for conservation, as they constitute important refuges for endemic or threatened biodiversity. Minimizing and controlling access will be important in maintaining this core.

Cane toads a threat to West Indian wildlife: mortality of Jamaican boas attributable to toad ingestion

The notorious “cane toad” (Bufo marinus) is considered to be one of the 100 worst invasive species in the world. A native of South and Central America, Mexico, and the Rio Grande Valley of the United States, this large toad was intentionally introduced to islands in the Caribbean, and subsequently throughout the southern Pacific, as a biological control agent to combat sugar cane pests. Unfortunately, the primary result of those introductions has been deleterious impacts on native biotas, primarily through competition and predation. More recently, the cane toad has devastated populations of amphibian-eating predators in Australia, through the ingestion of this highly toxic anuran. Elsewhere, however, the impact of the toad on native predators has not been documented. Here we report the first evidence that the cane toad is impacting native predators in other geographic regions. Specifically, we document death due to cane toad poisoning in the endemic and threatened Jamaican boa (Epicrates subflavus). To our knowledge, this is the first report of cane toads causing mortality in naturally occurring predators outside of Australia. Like all members of the genus, B. marinus secretes a powerful bufogenin toxin, which is often fatal if ingested by naïve species that have not co-evolved with Bufo species. Our results should therefore serve as a warning that other endemic predator species in the West Indies and elsewhere may be at risk. Thus, efforts to control the population growth and spread of cane toads may be of even greater conservation concern than previously recognized.

The effects of a hurricane on seedling dynamics and abiotic interactions in a tropical lower montane wet forest

We assessed seedling dynamics and understorey light before and after a hurricane in five randomly selected 5 × 5-m subplots, within 30 permanent sample plots covering a total area of 3750 m2 in a lower montane wet tropical forest, Jamaica over a period of 3 y. Understorey light increased (≈ 60%) following the passage of Hurricane Dean in 2007 but decreased in 2009. Overall, seedling density was positively related to light and survivorship was positively related to both light and density. Mortality was significantly lower and most species recorded their highest growth when the canopy was open (2007–2008). However, lower diversity during this period coincided with higher (average) mortality of uncommon species. The hurricane altered the relative importance of interactions between light, seedling density and dynamics. Consequently, interactions were significant before or 2 y after but not 1 y after the hurricane and their significance varied among the years and species. Periodic changes in the importance of these interactions and the effects of the hurricane were used to separate 12 common species along a continuum of responses, which ranged from positive (lower mortality), neutral to negative (lower growth). Our results indicate that hurricanes have positive and negative effects on seedling dynamics; therefore an increase in the intensity and frequency of hurricanes will likely alter seedling composition, and hence forest structure.

DNA barcoding of an invasive mammal species, the small Indian mongoose (Herpestes javanicus; E. Geoffroy Saint-Hillaire 1818) in the Caribbean and Hawaiian Islands.

Background and aim: The use of DNA barcodes has been proposed as a promising tool for identifying species. The efficacy of this tool for invasive species requires further exploration. The species status of the small Indian mongoose, an exotic invasive in several parts of the world, has been contentious due to morphological similarity with its congeners in its natural habitat. Although the small Indian mongoose is recognized as Herpestes javanicus, this nomenclature has been used interchangeably with Herpestes auropunctatus. Materials and methods: Here, we demonstrate the utility of using DNA barcoding approaches with mtDNA cytochrome b to discriminate between the two species and other sympatric members of the genus Herpestes (Herpestes naso, Herpestes urva, and Herpestes edwardsii). Using the diagnostic DNA positions we obtain, we can identity specimens of nonnative populations of the small Indian mongoose from the Caribbean and Hawaiian Islands to their species of origin. Results: A singe diagnostic site accomplishes the identification of H. javanicus versus H. auropunctatus. Conclusion: Our results indicate that the nonnative mongoose populations from the Caribbean and Hawaiian Islands are H. auropunctatus, and not H. javanicus.

Substrate mapping of three rivers in a Ramsar wetland in Jamaica: a comparison of data collection (hydroacoustic v. grab samples), classification and kriging methods

Most developing countries have failed to adopt hydroacoustics to aid with the management of their aquatic natural resources. We tested the ability of single-beam sonar (SBES) to discern and map substrates in three rivers from the largest wetland in Jamaica, the Black River Lower Morass (BRLM). We used five supervised classification methods (including C5.0; random forest, RF; and naive Bayes, NB) and four interpolation algorithms (indicator kriging (iks), fixed path simulation (fpth), random path simulations (rpth) and multinomial categorical simulation (mcs) based on transitional rates and incorporated into Markov Chain). Irrespective of the classifier used, mcs consistently produced higher overall classification accuracies (OAC) and kappa statistics; however, rpth interpolation produced the lowest balanced error rate (BER) recorded. For all three rivers, OAC, kappa and BER statistics were 49.7–87.1, 32.8–81.0 and 15.3–45.1% respectively. All interpolation algorithms produced maps with higher OAC and kappa indices from data classified using the tree-based classifiers (C5.0 and RF) in the absence of gravel-free substrates. At a lower spatial resolution, comparable maps were obtained by interpolating discrete sample points acquired by grab samples. Given that most of rivers in island states are small, sinuous, shallow and sometimes non-navigable by boat, the use of SBES as the most cost-effective and efficient way of mapping river substrates is questionable, but the interpolation of grab samples might suffice.