 |
|||||||||
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
|||||||||
|
|
|||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||||
The executive summary of this report provided below outlines the results of our work on the coral reefs of Montserrat. The report discusses the diversity and health of the reefs, the impacts of the current volcanic activity, a proposed marine park, and potentials for ecotourism. A full copy of the report is available at SEI, and in Montserrat copies are housed at Montserrat National Trust, Ministry for Agriculture Trade and Environment, and Physical Planning Unit.
1. The Caribbean region is a distinct Large Marine Ecosystem with characteristic physical and biological parameters. The region is bathed by warm water currents and sea temperatures vary little throughout the year. High biological productivity in coastal areas and low productivity offshore are characteristic features of the Caribbean.
2. Montserrat forms part of the leeward island chain, a geologically young archipelago that began to form less than 50 million years ago. The island is roughly pear shaped and characterized by steep volcanic mountains. The sea drops precipitously close to shore, and the 100 fathom contour line is less than 2 km from the coast around much of the island. Montserrat has a high energy, erosion-prone coastline, with volcanic beaches scattered around the island. There is only one white sandy beach in the north (Rendezvous Bay). There are few safe anchorages, and between November and March, strong groundswells affect the west coast. The east coast is exposed year-round.
3. There are three main coastal habitats in the Caribbean:
coral reefs, mangroves, and sea grass beds. All three habitats
are areas of high productivity and important to island biological,
fishery, and cultural resources. All three habitats are also in
decline. Coral reefs are among the most diverse and beautiful
natural environments. They occur only in warm and clear waters.
Corals provide food and habitat for hundreds of species of fish,
invertebrates, and plants. Biological factors, including predation,
competition, and mutualism, and physical factors such as hurricanes
combine to maintain the high diversity that characterizes coral
reef ecosystems. Coral reefs are in decline worldwide. It is estimated
that 10% of the world's reefs have been lost and that if current
patterns continue, then by the year 2010 a further 30% will be
lost. In response to this decline many countries are enacting
protection laws, and designating parks to halt reef degradation.
(Image 1 shows divers collecting reef data using photoquadrats).
Click on this thumbnail to see
full size image.
4. In 1995 and 1996 we carried out a series of studies to
document the biological diversity of Montserrat's coral reefs.
The goal of the study was to document the reef patterns with
a view to marine park development. This was one of the first scientific
studies carried out on the reefs. We used a range of scientific
methods to survey the reefs. Sessile species such as corals, sponges,
and marine plants were surveyed using photoquadrat analysis. In
addition during 1995 and 1996 we set up a series of permanent
quadrats at selected sites. Mobile invertebrates (e.g. crabs,
starfish etc.) were recorded using 10 meter transects. Fish abundance
and diversity was estimated using 20m visual transects.(Image
2 collecting sediment traps on the reefs).
Click on this thumbnail to see full size image.
The start of our study coincided with the beginning of the Soufriere Hills volcanic eruption, which is still ongoing. Ash and sediment from this eruption is falling on the reefs. To measure sediment levels on the reefs we recorded sediment depth and set up a series of underwater sediment traps. Water clarity and turbidity were estimated using secchi disks. We carried out aerial surveys of the reefs, and estimated rate of sediment input to reefs from volcanic origin, and conducted surveys of affected reefs to document changes in the health of the reef system.
5. This study provides a baseline study for future comparisons,
and the monitoring program can continue to be run either by other
researchers or locally trained personnel. (Image 3: giant
and tube sponges abound in Montserrat).
Click on this thumbnail to see full size image.
6. Montserrat's reefs are rich and biologically diverse. During our surveys we recorded 37 true coral species, 17 gorgonian and other octocorals, 87 invertebrate, 3 seagrass, 37 algal species, and 67 fish species. Not all individuals could be identified to species level as this can require microscopic or genetic analysis.
7. Montserrat's reefs are a series of patch reefs interspersed
with sand and sediment. Corals and other sessile species are
found on rocky outcrops, rather than older coral remains. Corals,
algae, and sponges occupy most of the primary space. Corals occupy
from 20-45% of available space, and algae (marine plants) cover
from 23-41% of space. Dictyota is the dominant algal species.
Coral diversity is high but individual coral heads tend to be
small. The number of coral species did not vary among sites, except
that we recorded fewer species in heavily sedimented areas. There
was a decrease in the abundance of finger corals (Porites) between
1995 and 1995 mainly due to hurricane damage. Gorgonian corals
are abundant, but elkhorn corals are rare in Montserrat waters.
A striking feature of Montserrat's reefs is the abundance of invertebrates,
anemones are common and have a range of cleaning shrimp and crabs
associated with them. The density of sea urchins varies significantly
among sites. (Figure 11 shows the composition and distribution
of the main sessile (attached) species in 1996 and 1996: Gari=Garibaldi
Reef; Carrs=Carrs Bay Reefs; Rend=Rendezvous Bay; Colbys=Colbys
Reefs).
Click on this
thumbnail to see full size image.
(Figure 12a shows the composition and distribution of coral
species in 1995 and 1996).
Click on this thumbnail to see full size
image.
8. Plankton feeding fish dominate the coral reef fish assemblage.
Two families the labrids (wrasses) and pomacentrids (chromis and
damselfish) dominated the fish community. (Figure 14 shows
the abundance and distribution of predominant fish families).
Click on this thumbnail
to see full size image.
Juvenile wrasses are among the most abundant species. Fish abundance decreased significantly between 1995 and 1996 possibly as a result of Hurricane Luis. Fish are patchily distributed within and among reefs. Fish are generally less abundant on heavily sedimented reefs. Ghost fish pots are occasionally found on the reefs and these trap and kill a variety of reef fish species. Hurricane Luis removed a number of ghost and active fishing pots, probably to deeper waters, and there were fewer ghost pots observed in 1996.
9. Sediment depth differed significantly among sites.
Rendezvous Bay in the north of the island had the least amount
of sediment. This area is in the drier region of Montserrat and
is unaffected by sediment or ash from the volcano. Garibaldi Bluff
had higher sediment loads, and the inner region of the reef had
the highest sediment input. Secchi disk measurements showed that
water clarity was often significantly reduced within 100m of shoreline.
This was mainly due to runoff resulting from rains and volcanic
activity. (Image 7: Brain coral buried by volcanic sediment
and ash).
Click on this
thumbnail to see full size image.
Helicopter surveys showed that the vegetation had been destroyed
in the vicinity of the volcano and increased soil erosion was
leading to high rates of sediment input into the sea. At Whites
River sediment load ranged from 130-150 g dry weight/liter of
water.Water flow into the sea was estimated at 1.5m/sec. (Table
1 shows water clarity (an indirect measurement of sediment and
nutrient load).Click on this thumbnail
to see full size image.
10. Garibaldi reef is subject to ash falling from volcanic eruptions and sediment input through the Belham river. Our surveys in 1996 showed that the reef is showing signs of stress. Part of the reef was covered in a red algal mat that trapped sediment over the corals (see image 7). In addition, six sponges had severely disintegrated. 64% of Agaricia colonies were bleached.
11. The volcanic nature of the island plays a large role
in the abundance and distribution of coral reefs around Montserrat.
Evidence suggests that reef is limited by the availability of
hard substrate. High runoff rates from steep slopes limit the
establishment of coral reefs. Volcanoes also affect the relative
abundance of corals, sponges and algae and the consumers that
feed on these species. Volcanic islands have higher rates of runoff,
which limits coral growth, but provide high nutrient input. High
nutrients favor algal (plant) growth, and algae dominate many
of the reefs in Montserrat. Additional evidence supports the suggestion
that Montserrat's waters are nutrient rich, for instance, there
is an abundance of sponges and planktivorous fish. One algal species,
Dictyota, is dominant. We do not know what accounts for
its dominance but it may be related to the abundance of sea urchins
Diadema antillarum. This urchin suffered mass mortality
in the 1980s and Dictyota increased in many of these areas.
However without data from Montserrat during the 1980s, we can
only speculate as to the reason for Dictyota dominance.
Individual corals are small and this may be due to high sediment
loads, or poor light condition. Further research on these questions
are warranted. (Image 8: Plankton-feeding chromis fish live
and feed in large schools at the reef edge).
Click on this thumbnail to see full size image.
12. Sediment accumulation and resuspension in water is a natural processes that can be greatly impacted by anthropogenic activities, and by naturally occurring events including volcanoes and hurricanes. Sedimentation can affect growth rates, calcification rates, species richness, and zonation patterns. It can be difficult to distinguish between direct impacts of sediment, and indirect impacts through reduced light or salinity levels. Susceptibility to sedimentation varies among species, small polyp species and plate-like growth forms are more susceptible to mortality. There are three main sediment sources on Montserrat's reefs: volcanic ash deposition directly from the air, ash and debris runoff from the land, and resuspension and redeposition of benthic sediments. Increased sediment input, resulting from volcanic activities that occurs from the east to the southwest of the island is of concern. Sediment load changes the limit of the euphotic zone (the depth at which photosynthesis ceases to occur), and we have recorded situations where the reef lies below the euphotic zone. In addition sedimentation has covered some reefs in the south of the island. The north of the island receives little sediment input and water clarity is consistently high. Continued sediment input may change the distribution and diversity of the reefs and need to be monitored.
13. The marine environment is critical to the natural and cultural heritage of the world. Many communities depend on marine resources for economic well-being. Coral reefs are in decline world wide and important commercial industries (e.g. fishing) are declining as a result. To halt the decline and to sustain the reef environment, many countries are designating Marine Protected Areas (MPA). When well-managed a MPA can conserve diversity, sustain fisheries, and promote ecologically sensitive tourism. The Caribbean region now has 104 MPAs. There is general support for the development of a marine park in Montserrat. The development of such a park involves the support and education of the local community, the development of clear goals for the park, use of well-defined criteria to identify park areas, and a plan for operating, monitoring, and managing the park. The report discusses each of these areas in detail.
14. One of the main obstacles to successful park monitoring and management is funding. Many countries are finding new ways to make parks and protected areas self-sustaining. These include, user fees, environmental trust funds, environmental cost recovery charges. In addition new partnerships among government, non-governmental organizations, and the private sector are ensuring better funding, monitoring and management of marine protected areas.
15. We propose a marine park system for Montserrat that is based on a zoning system, similar to that which has been successfully used in other MPAs, including Cayman Islands and the Great Barrier Reef Marine Park. Based on our biological surveys, on current uses and physical plans for Montserrat, and on other economic, social and cultural criteria developed by Kelleher and Kenchington (1992) we propose three main zones: fishery zones dedicated to fishing and stock enhancement, marine reserve zones dedicated to education, research, conservation and recreation, with no fishing or collecting allowed in the reserves, and a marine preserve dedicated as an environmental safety zone to protect reefs and fisheries, and act as sources of new recruits for the reef and fishery, and with no fishing, diving or other activities in the preserve apart from monitoring by park personnel For the fishery zone we recommend the following areas: from Foxes Bay to O Garros to the 100 fathom contour line, South of Marguerita Bay to the airport to the 100 fathom contour line, and Carrs Bay to Old Road Bay from outside the 10 fathom line to the 100 fathom line. These areas rank highly with respect to economic and social importance. For the marine reserve zones we recommend the following areas: Garibaldi Bluff reef; Pinnacle; Potato Hill Reef; Little Bay to Rendezvous Bay; Old Road Point to Carrs Bay inside the 10 fathom contour line; O Garros; Roches Bluff to Spanish Point to the 100 fathom contour line. These areas rank highly with respect to biogeographic, ecological, naturalness, scientific importance and economic importance criteria. For the marine preserve we recommend from North of Rendezvous Bay to Marguarita Bay to the 100 fathom contour line. This ranks highly as a high diversity and source area. If these recommendations are followed then of the waters to the 100 fathom contour line 55% will be designated for fishery, 25% as a preserve, and 20% as marine reserve.
16. Ecotourism is responsible tourism based on conserving the environment and sustaining the well-being of local economies and cultures. It is the fastest growing segment of the tourism market. Ecotourists visit natural areas in search wildlife, flora and fauna and activities that allow them to study nature. They are concerned that the areas they visit are well protected. Many countries are now looking towards ecotourism as a way of conserving natural resources and the economy. Montserrat has the potential to develop an ecotourism industry based on its marine and land resources. However, this must be carefully planned to ensure that the resources are not destroyed leading to collapse of the ecosystem and the economy. We propose that ecotourism in Montserrat be developed around a research and ecotourism center. This center can co-ordinate visitor activities and programs, provide a center for research and education. The model is based on a successfully operating ecotourism and research program in Costa Rica. Costs and development concepts are included in the chapter.
© 2000 Sustainable Ecosystems
Institute
 comments: sei@sei.org |