Does a higher degree of complex root systems have a higher diversity of root fauna, and do epifaunal communities change with shore height/immersion times? Animals such as oysters, mussels, littorina, sesarmid crabs and sponges are integral to the community structure of mangroves enhancing system diversity. Some of these animals filter the water and some are important detritivores that process decaying leaf litter. Therefore, many of these species are important in the trophodynamics of mangrove energy pathways. These animals rely on hard surfaces at low tide such as prop roots. If wood harvesting continues, will these animal communities decline? One project could look at the diversity of fauna associated with prop-roots in different mangrove zones and could involve detailed ecological studies within the mangrove followed by sorting and identification at the marine facility.

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IH291 Ecology and behaviour of fiddler and sentinel crab populations, Indonesia (Weeks 2 - 8; need to have completed IH007)

Mixed populations of fiddler crab occur in some intertidal areas of the Wakatobi, but the same species also occur in single-species populations, e.g. Uca vocans on the Ambeuan mudflat, or U. tetragonon at the western end of Pantai Pogo (near the village of Furake) and U. mjoebergi at the eastern end of the same bay. There are a number of comparative studies that could be done to investigate how competition with other species is affecting the feeding time, feeding areas and activity budgets of each of the species, and resource partitioning of the intertidal areas. Both mixed and single-species populations of two species of sentinel crab, Macrophthalmus convexus and M. serenei, occur in some numbers at the top of the low tide sand flat on Pantai Kampoa. How do these species partition the resources and are there interactions between the species?

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IH292 Mangrove root-tissue re-generation in Indonesia

(Weeks 2 - 8; need to have completed IH007)

Do mangrove woody tissues have the ability to recover when damaged in their dynamic environment? Mangrove habitats are essential for the health of adjacent ecosystems, such as seagrass beds and coral reefs, as the mangroves sequester and trap fine sediments within their root systems and for their role as vital nursery grounds for many juvenile crustacean and fish species located within the complex root systems at high tide. Anthropogenic activities, such as mangrove wood harvesting, could be highly damaging but the extent to which mangrove species can recover from such impacts has been little studied. One project could assess the regeneration potential of damaged mangrove root systems. Natural damage to root systems could be assessed at various zones and repeated assessments used to determine the rate at which tissue recovers. Snorkelling may be useful but this project will need only limited in-water activity.

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IH293 Detrimental impacts upon mangrove faunal community structure facilitated by wood removal in Indonesia

(Weeks 2 - 8; need to have completed IH007)

To what extent does the harvesting of mangrove materials reduce the biodiversity of these important ecosystems? The majority of mangrove animals exploit the available hard substrates within these extreme environments. Areas such as mangrove prop roots and, in particular, large wood detritus (LWD) are a favoured habitat for the majority of mangrove fauna. However, exploitation of mangrove systems and removal of both live trees and LWD will inevitably reduce available habitat. Limited information is available on extraction rates (live wood to LWD), natural levels of LWD and consequences of its removal for biodiversity. One project, which would require trekking through mangrove forests, could examine the importance of LWD for system biodiversity and evaluate the consequences of its removal.

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IH294 Mangrove habitat complexity in Indonesia

(Weeks 2 - 8; need to have completed IH007)

Does a reduction of mangrove habitat complexity result in a reduction of biodiversity? Much tropical research has examined the association between loss of structural complexity and loss of biodiversity, particularly on coral reef systems. Like coral reefs, mangrove forests are also in decline and their habitat complexity is also under threat mainly through anthropogenic actions, such as wood extraction and land clearance. However, unlike coral reef systems, very little is known about the association between habitat complexity of mangrove systems and associated biodiversity. One project, which would involve trekking through and sampling of the mangrove forest, aims at quantifying mangrove complexity and the association between complexity and species diversity across a range of spatial scales and disturbance levels.

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HB295 Seagrass ecology in Honduras

(Utila: Weeks 2 - 5 and Cayos Cochinos: Weeks 6 - 10; need to have completed HU007 or HC008)

Utila is surrounded by seagrass beds, but these beds are subjected to a variety of disturbance and pollution from the developing town. Assessing the health of the seagrass beds and their associated macrofauna is vitally important to their survival. Projects will use snorkelling to assess aspects of the health and ecology of the seagrass beds. The undisturbed seagrass beds of Cayos Cochinos provide an excellent comparative site with their pristine seagrass beds. Elements of study can include quantifying macrofauna and algae distribution within the beds and studying the relation this has to environmental variables including indicators of pollution and disturbance. The results of the study will be used to form part of a long term monitoring program of seagrass status around Utila and Cayos Cochinos MPA. Note this project can be done by snorkelling only.

HU296 Assessing the impact of mangrove degradation on their functionality in Honduras (Weeks 2 - 8; need to have completed HU007)

The island of Utila is dominated by mangrove and wetland systems. These are highly important to the functioning of the entire marine ecosystem on the island through their role in coastal protection and as fish nurseries. However, they are being placed under increasing threat from the development on the island, either through direct removal to clear space for construction, or more commonly through partial disturbance and pollution. Many previous studies on mangroves have compared the functioning of healthy systems to areas where mangroves have been completely removed, but little has been done on the impacts of degradation on mangrove systems and its effect on their functioning. This topic allows research to be done on mangroves in four contrasting lagoons. Of these lagoons, one is subjected to high levels of organic pollution, while a second is subjected to physical disturbance from dredging and boat traffic, a third contrasting lagoon is relatively untouched and a fourth is part of a marine reserve. These contrasting systems provide an excellent opportunity to study the effects of differing levels of mangrove disturbance on sediment stability using cores and a muffle furnace to determine bulk densities of sediment. Another option is to compare the epibiont fauna of the mangrove roots to see if these correlate with levels of organic pollution. Estimates of the health of the mangroves can be made from the percentage of shoots that reach the sediment and the abundance and size of leaves on sample branches. This project is ideal for students studying environmental degrees and projects can analyse a variety of environmental measurements and potentially present the data through GIS. However, this topic can also be developed as a biological study by assessing the impact of mangrove degradation on their value as a fish nursery using trapping. On this topic, students will be kayaking around the remote mangrove lagoons, exploring and surveying areas of Utila that are rarely, if ever, seen by other people.

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