Environmental science topics

HO106 Prevalence of chytrid in amphibian populations within Cusuco

(start dates 07 June, 14 June or 21 June;need to complete HO001)

This project has a waiting list

The effective conservation of Cusuco National Park is imperative for many endemic species, none more so than cloud forest amphibians. The spread of chytrid fungus has caused severe declines in many amphibian populations and is a major concern for global amphibian conservation. Chytrid is known to have been present within the amphibian populations of Cusuco for at least 15 years, but its prevalence within specific areas of the forest and the extent to which different species are affected are not well known. Amphibian species will be encountered during diurnal and nocturnal transects and swabbed for chytrid. Swabs will be taken back to the lab at base camp and tested for the presence of chytrid using polymerase chain reaction (PCR) and visualised using agarose gel electrophoresis. Individuals will also be assessed for visual signs of infection. Prevalence of chytrid will be mapped in the park using multiple years’ data to assess whether the disease is continuing to spread to previously uninfected areas to contribute to the investigation into the underlying mechanism of infectivity.

Extended Project Summary


HO108 Factors affecting bird communities in the cloud forests of Cusuco

(start dates 07 June, 14 June or 21 June;need to complete HO001)

Birds are excellent indicators of forest ecosystem health as their abundance and diversity are closely related to habitat disturbance and they make ideal models because they are relatively easy to monitor and study. This topic takes advantage of the existing fixed point count survey work being undertaken for birds at over 130 survey sites across Cusuco, as well as the recently started mark-release-recapture mist netting survey data. By examining species distributions and species richness across varying habitats, projects could: compare bird communities in different administrative divisions of the park (e.g. the buffer/core zones that differ in degrees of wildlife preservation and human activity); study the impact of differing disturbance levels on bird communities; investigate the impact of habitat type on bird community composition; or look at the effect of altitude on bird composition. By using covariates such as temperature, habitat structure and forest type, threshold limits for the different species could be elucidated which may have interesting implications for the impact of habitat alteration (e.g. by deforestation) in the future.

Extended Project Summary


HO109 Variation in cloud forest small mammal populations and their microhabitats, Honduras

(start dates 07 June, 14 June or 21 June;need to complete HO001)

A total of 19 small mammal species have been recorded in Cusuco National Park comprising a complex community. However, three focal species are of interest and dominate the community: 1) Desmarest’s spiny pocket mouse (Heteromys desmarestianus) which occurs on the forest floor >150m from the nearest river (terrestrial environment), 2) the Mexican deer mouse (Peromyscus mexicanus) which occurs along river corridors <3m from the water’s edge (riparian environment), and 3) a currently unidentified Rheomys spp. watermouse which is entirely aquatic and forages by diving within upland rocky streams (riverine environment). Therefore, three traplines are set at each of seven camps throughout the park, each consisting of 12 traps placed approx. 10m apart. These traplines are set up in each microhabitat targeting each of the three small mammal species for comparative and individual study. How these species share the forest and the individual specialism of each species remains largely unknown. Small mammal abundance and species composition can be related to habitat data collected from permanent plots along the transect network (for example forest structure, tree density, % fruiting, leaf litter depth etc.). Additionally, abundance and special distribution patterns may be related to predator abundance and distribution (mainly large snake species including Wilson’s pit viper, Cerrophidion wilsoni), building up a picture of the trophic relationships in the region.

Extended Project Summary


HO112 Tracking the recovery of a keystone urchin species and its role in reef restoration

(start dates 14 June, 21 June or 28 June; need to complete dive training and the Caribbean reef ecology course)

This project has a waiting list

Under natural conditions, the sea urchin (Diadema antillarum) is the most important herbivore on Caribbean coral reefs, and is therefore considered a keystone species. However, a disease in the 1980s caused the death of an estimated 98% of individuals throughout the region. This mass mortality event had a devastating effect on reef health, driving subsequent phase shifts to algal dominated benthic communities. Recovery has been extremely limited, with populations on most reefs still severely depleted, and Utila Island is a classic example of this. Remarkably, the Banco Capiro reef system in Tela Bay has a population density of D. antillarum at astonishingly high levels. It also boasts extremely high benthic reef health, despite historical overfishing leading to a complete collapse of the fishery. Since its recent discovery, Operation Wallacea scientists began detailed population studies in 2013 and this project will continue to build on this. The primary objective is to quantify changes in the abundance, biomass and population structure of D. antillarum on the reefs of Utila and Banco Capiro. Further data will assess the potential roles of competition, predation and environmental factors in driving the recovery on Banco Capiro.

Extended Project Summary


HO113 Managing the Caribbean lionfish invasion

(start dates 14 June, 21 June or 28 June; need to complete dive training and the Caribbean reef ecology course)

This project has a waiting list

Lionfish are an invasive species in the Caribbean and are having a devastating impact on local fish communities throughout the region. Introduced in the 1980s, believed to be by accident, lionfish have spread extremely quickly and are now found as far as New York City and Brazil. Their success is down to a number of factors, including their high reproductive rate, generalism in terms of both diet and habitat, and a lack of natural predators. They are now considered to be one of the greatest threats to the future of Caribbean coral reefs and their fish communities. Management approaches to dealing with the lionfish invasion are limited, with one of the most common being direct removal via spear fishing. This relies on regular visitation to individual reef sites, as studies have shown full recovery of lionfish populations only five months after complete removal. Baseline data will be collected on population densities of lionfish at sites of varying intensities of culling. Lionfish will subsequently be removed and morphometric measurements taken along with dissections for physiological and gut content assessments, which can link fish assessments to gauge prey availability. In addition, lionfish behavioural responses to divers, such as Flight Initiation Distance (FID) and Alert Distance (AD) can be assessed, which could also be expanded to include commercially valuable fish such as grouper.

Extended Project Summary


IN124 Coral reefs and environmental change

(start dates 20 June, 27 June or 04 July; need to have completed reef survey techniques course and be dive trained if incorporating a diving element into the research)

This project has a waiting list

The implications of short and long-term environmental change have been widely discussed in the scientific literature and media. The sensitivity of reef building corals to environmental conditions varies greatly between species. It now appears that the most sensitive species tend to have a branching or tabulate growth form. Such species, most often belonging to the genus Acropora, greatly add to the physical complexity of the reef scape. Their loss from the system will reduce physical rugosity and most likely biological diversity, and the implications of this loss needs to be carefully considered. The 2016 thermal anomaly had a limited impact on reefs of the Wakatobi as compared to other regions, although the impact was greatest on branching and tabulate corals particularly in shallow waters. This leads to worrying uncertainty over whether fish species formally associated with these growth forms are still abundant or whether they have also been lost from the system. The ecological consequences of the loss of these fish depends on the species in question and their larger role in the ecology of these reefs. Research is required that examines the relationship between branching and tabulate corals, and the degree of fidelity that exists between these habitat types, resident fish species and the sensitive coral growth forms. Dissertations in this field could also focus on the abundance of branching and tabulate corals across reef sites and reef zones to determine the actual impact of the 2016 bleaching event on the reefs of the Wakatobi.

Extended Project Summary


IN127 Seagrass and patch reef ecology

(start dates 20 June, 27 June or 04 July; need to have completed reef survey techniques course)

Tropical seagrass beds are extremely important and provide numerous ecosystem and ecological services. The Wakatobi harbours some of the most biodiverse seagrass beds in the world. Seagrass habitat has been shown to provide refuge and nursery grounds for many economically important invertebrates as well as for fish, with some species being seagrass specialists whilst others migrate from the reef into seagrass beds daily or at specific points in their life cycle (ontogenetic migration). However, like many other important habitats in the world, seagrasses of the Wakatobi are threatened by numerous anthropogenic activities including fin-fisheries and invertebrate over exploitation, trampling, and by the presence of intertidal seaweed farms. The implications of these activities in isolation and when combined have not been fully explored or quantified in terms of their ecological or economic costs. Research is required that examines the implications of these activities for seagrass productivity, biomass and biodiversity and resulting consequences for permanent as well as transient invertebrates and fish that depend on the system for food or refuge. Seagrasses within the Wakatobi extend from the low tide mark through to the reef flat. This transition zone is characterised by intermittent coral patch reefs. The ecological significance of these coral patches, not only in terms of total biodiversity but also through the provision of nursery areas and transient “stop-over” sites utilised by fish migrating from reef to seagrass, has not been fully explored. Therefore within this research topic the ecological services of shallow subtidal patch reefs could be explored and questions investigated regarding their conservation value.

Extended Project Summary


IN129 Evaluating potential effects of rising environmental temperatures on thermal ecology of fiddler crabs, Uca spp.

(start dates 20 June, 27 June or 04 July)

Often exhibiting high levels of biodiversity and endemism, mangrove forests demonstrate a remarkable interdependence between local flora and fauna such that a loss of diversity or density in one group has marked adverse effects on the other. Declines in burrowing crustacean populations, for example, have been shown to result in reduced organic turnover, decreased nutrient and energy cycling, and diminished primary productivity in mangrove species. Fiddler crabs (Uca species) are one of several semi-terrestrial, burrowing, mangrove decapods making up a keystone group commonly referred to as engineers. Indonesia boasts the highest diversity of fiddler crab species of any country in the world with 14 total species, seven of which can be found within an area of 4-square meters within the Ambeua Mangrove near Hoga Island. Previous research at the Hoga Marine Laboratory has shown that local fiddler crab populations are relatively tolerant of high temperatures; however, with environmental
temperatures across the Malay Archipelago expected to increase by up to 4°C in coming decades, it is unclear how fiddler crab populations and ultimately mangrove ecosystems, may be affected. Potential dissertation projects could evaluate differences in thermal adaptations of Uca spp. occupying different intertidal regions, or may look at acclimation responses of a single Uca species. All studies would include a field observation component, though most of the empirical work would take place in the Hoga Island Research Laboratory. Students are strongly encouraged to contact their project field supervisor early in the proposal development process.

Extended Project Summary


ME150 Understanding the non-conventional cenote-mangrove forest system

(start dates 12 June or 26 June)

The Yucatan Peninsula is formed of limestone karst substrate that was once coral reef. As limestone is porous, rainwater seeps through the rock surface to form an extensive network of underground rivers accessed from the surface by sink holes, known locally as cenotes. Mangrove forests associated with cenotes in coastal regions are not new, but research of them is. This novel project aims to investigate the driving forces behind the structure and function of these unusual mangrove ecosystems and to investigate differences of animal community structure in comparison with coastal mangrove forests. The majority of mangrove animals exploit the available hard substrata within mangrove ecosystems. Areas such as mangrove prop roots and in particular large wood detritus (LWD) are favourable for most mangrove fauna, but nothing is known about the organisms that process the fixed carbon in cenote mangrove forests. Projects may highlight new and unreported information from forest structure and function, to mangrove fauna diversity and niche separation. Continuous belt transects and plots will be used to establish the tree structure, composition and basal areas with the cenote mangrove forests. Biodiversity assessments of the fauna upon mangrove roots, substratum and LWD will be made, and animal observations will be employed. Degradation processes of LWD will be recorded in the forests and compared with those from conventional mangrove forests.

Extended Project Summary


PE152 Tropical butterfly diversity and environmental gradients

(start dates 11 June or 25 June)

This project has a waiting list

The forest of the Pacaya-Samiria Reserve is awash with a diversity of bright and colourful butterflies and moths (Lepidoptera), notably including species of the beautiful blue morpho. Lepidoptera make excellent indicators of environmental change due to their variety of life-history strategies and their rapid life cycles. The Lepidoptera of the Pacaya-Samiria are monitored using baited catch-and release traps containing fermenting fruit, sugar water or salt water, each attracting a different suite of species. This allows a number of research questions to be examined. Projects could investigate the niche-partitioning of butterflies and moths according to food source and food availability within forest types; alternatively the diversity and community composition changes along the natural environmental gradients from forest edge to centre could be studied; temporal niche-partitioning between butterflies and moths and whether the response to forest edges differs between day and night is also of interest; additionally, there is an opportunity to study the vertical stratification of the Lepidoptera community between the understorey and the mid-canopy. Permission is not granted to collect specimens, but as a diverse and abundant study group, the Lepidoptera project can be tailored to address any number of environmental questions, whilst also contributing to the long-term climate change data set.

Extended Project Summary


PE153 Potential impacts of climate change on sustainable fishing resources for the Cocama indigenous people

(start dates 11 June or 25 June)

This project has a waiting list

The fish populations of the Pacaya-Samiria Reserve are a vital resource for the local Cocama people, making up to 70% of the protein in their diet. Fund Amazonia and Opwall have been monitoring the fish populations of the Pacaya-Samiria Reserve for eight years and have seen dramatic fluctuations in abundance and diversity in response to changing water levels. This means there is huge potential for continuing climate fluctuations to affect the fish community and hence the people who depend on them for their livelihood. This project could combine studying the fish abundance and diversity responses to climate change using the long-term datasets, coupled with the sociological impact of these changes on the local indigenous people. Fish sampling is carried out using 30m x 3m gill nets with 3 inch mesh and fished for as close to one hour as possible. The fishing locations are chosen by our local guides to imitate the genuine fishing conditions of local people. Sociological data regarding how the changing fish populations are affecting the type of fish eaten, the amount of time spent fishing and the fishing methods being used could be collected by interviewing local guides and by organised visits to nearby Cocama villages.

Extended Project Summary