June 12, 2007
To Whom It May Concern:
I am writing to express my concern over conservation issues on Isla Bastimentos, and other islands in the Bocas del Toro province of Panama. As a biologist studying birds on the Bocas del Toro Archipelago, I can vouch for the biological uniqueness of this area and the urgent need for stronger conservation measures.
The birds of the Bocas del Toro Archipelago were not well-studied until the Smithsonian Bocas Expedition (SBE) in the late 1980s and early 1990s began systematically sampling on each island. Below I will highlight some of the notable finds of that expedition, as well as some of the preliminary results of my own more recent research. I will conclude with some more detailed thoughts on conservation issues relevant to the Bocas del Toro Archipelago.
Mangrove cucko in a mangrove tree
One of the more notable finds of the SBE included 2 Mangrove Cuckoos (Coccyzus minor) on Isla Solarte, an island separated from Bastimentos by a narrow mangrove channel. This species is known to be uncommon on the Pacific side of Panama and has never before been found on the Caribbean coast between northern Costa Rica and Venezuela. Thus, the mangroves of Solarte and Bastimentos are likely an area of critical importance for this rare species. The proposal by Red Frog Beach Club to develop a marina in Bahia Honda, the narrow bay between Solarte and Bastimentos, along with the greatly increased boat traffic a marina such as this would cause, would likely directly affect this species if it regularly occurs here, and especially if it is breeding. More surveys are needed to determine the status of this bird, but its presence highlights the importance of mangrove conservation in this area.
Stub-tailed Spadebill (Platyrinchus ancrominus)
Of all the birds discovered by the SBE, the Stub-tailed Spadebill (Platyrinchus ancrominus) was perhaps the most surprising. Prior to the expedition, this species was unknown in Panama. Its closest mainland relatives are on the Pacific slope of northwestern Costa Rica. Though no genetic work has been done on this species, the Bocas del Toro race is likely a unique subspecies. It is an uncommon to locally common resident of the understory of mature and second growth forests of the Bocas del Toro Archipelago, but is entirely absent from the mainland. It is likely sensitive to understory clearing.
Another surprising discovery made by the SBE was the presence of two subspecies of Green Honeycreeper (Chlorophanes spiza arguta and C. s. subtropicalis). C. s. arguta is found throughout the Panamanian mainland, as well as on the more recently formed islands of San Cristobal and Popa. However, two individuals found on the much older island of Bastimentos have the blue-green plumage of C. s. subtropicalis, its nearest mainland relatives found in the Andes of Colombia and western Venezuela. Proposed development on Isla Bastimentos will likely also affect this bird of forest canopies, which molecular genetics studies will likely show to be a rare subspecies unique to Bastimentos. The discovery of this species highlights the importance of Bocas del Toro as a biological crossroads between North and South America. Further study will increase our understanding of the ecological and climatic forces that allowed some South American species to expand their ranges northward historically, and also the reasons for the subsequent retreat of some species which have left relictual populations on the islands of Bocas del Toro. There are several other North/South American species pairs that currently meet and change over in Bocas del Toro including the Scarlet- and Sulfur-rumped Tanagers (Ramphocelus spp.) and the Golden and White Collared Mankins (Manacus spp.), both on the mainland.
The Golden Collared Manakin (Manacus vitellinus), the subject of my studies, also shows complicated and unusual variation across the islands and mainland of Bocas del Toro. The birds found on Isla Bastimentos are significantly larger than their mainland counterparts (although smaller than those found on Isla Colon and Isla Escudo), and surprisingly give a vocalization different from the Golden Collared Manakin. Thus, they show unique phenotypic differences that make it worthy of conservation as a separate subspecies. Similar, though even larger, manakins found on Isla Escudo, the oldest and most isolated of the Bocas del Toro islands, date the likely origin of this subspecies to greater than 10,000 years ago. It was probably once present on the mainland too, during a time when sea levels were lower (during the last ice age) and all of today’s islands were attached to the mainland by “land bridges”. However, pure Golden Collared Manakins and White Collared Manakins appear to have subsumed its ranger there as the climate changed, leaving it isolated on the islands today. There are also other differences between the Bastimentos manakins and their mainland counterparts: Island birds are more social, the males forming extremely large groups, and building display courts (used in female attraction) that are much larger than their mainland counterparts, and often much closer together. The behavior and genetics of these birds on Bastimentos warrants more study. This species often occupies forest edges, and can be found in mature second growth forest, as well as oldgrowth. It is not tolerant of large-scale clearing, however, and it is particularly sensitive to clearing of the forest understory, a practice often employed by developers in this region.
The avifauna of the Bocas del Toro Archipelago is also notable for what it lacks. Perhaps most notable is the absence of toucans from Isla Colon and Isla Bastimentos. Presumably these species were present when the islands were attached to the mainland, but we have no idea what led these species to go extinct on these islands. Presumably the habitat is suitable. The water distance from Isla Popa to Bastimentos is less than 1 km, and even less if one takes into account the many intervening mangrove islands. It would seem that these large birds could cross the gap if they so desired, but maybe water gaps of this size are indeed insurmountable.
Isolated populations of species no longer found on the adjacent mainland and other islands give us insight into the former ranges of many species and the ecological requirements that might have caused their retreat or continued persistence. It should be noted that these unusual biogeographical patterns are not restricted to birds. Similar patterns can be seen, for example, in pit vipers which are absent from Isla Bastimentos, yet present on Isla Colon and Isla Escudo. A similar pattern can be seen in a squirrel species that is restricted to Isla Colon whose closest mainland relatives occur in northwest Costa Rica and Nicaragua. The patterns are not restricted to fauna either. A Smithsonian sponsored rapid diversity assessment in which I participated in 2003, discovered a species of tree on Isla Bastimentos, that had never before been recorded in Panama, its closest relatives being in Costa Rica.
Dendrobates pumilio, Bocas del Toro
A combination of processes, including hybridization and isolation on islands has also likely allowed for the evolution of novel subspecies not found outside of the islands. This is evident not just in birds like the Golden Collared Manakin, but also in other taxa such as sloths and the multiple unique morphs of the poison dart frog, Dendrobates pumilio, found in Bocas del Toro. Isla Bastimentos alone has four distinct morphs that are found only on that island. All are found only in mature shaded forest with intact understory. Many other taxa, including invertebrates and fish in the freshwater streams of Bastimentos and other islands are entirely unstudied. Due to their isolation, there are likely many unique species and subspecies waiting to be discovered in these habitats. The Bocas del Toro Archipelago has often been called the “Galapagos of Central America”. This title is not far off the mark. These islands are a living laboratory for understanding evolutionary and ecological processes, such as speciation, historical and present day biogeography, and the affects of climate change. It should be noted that the only terrestrial protected areas constitute a disproportionately small section of Isla Bastimentos. None of the other islands have any formal protection. We are only just beginning to document the unique combinations and morphs of flora and fauna on these islands, and the ecological forces behind present day and historical biogeographical distributions in Bocas del Toro. The islands offer us unique opportunities to understand the speciation process in the species-rich lowland tropics.
The lack of terrestrial protection is even more alarming when one considers the impact of forest clearing and subsequent sedimentation on marine ecosystems. Healthy marine ecosystems are essential to the future conservation of this entire area and the survival of local human populations. Bocas del Toro is perhaps best known for its coral reefs which have spawned a booming tourism industry. The Bastimentos marine park protects only a fraction of these reefs and, according to Smithsonian research scientist Hector Guzman, many of the most diverse reefs sit beside terrestrial areas that are unprotected. The region can likely handle more small scale development projects that take into account the conservation of the ecosystems that tourists come to see. It cannot handle large scale development that destroys natural ecosystems rather than protecting or restoring them. Small scale tourism projects should be developed in conjunction with the indigenous communities present on these islands, rather than adding unsustainable development to currently undeveloped areas, and excluding the local people from participation and profit. The indigenous communities present on the islands understand that intact ecosystems are essential to their own survival, and that increased income from sustainable tourism can also decrease their direct dependence on the land. Large scale development projects that exclude the indigenous population destroy or alter large sections of land and sea, and relegate these already poor people to continued poverty and continued dependence on diminishing natural resources.
At the very least, thorough, large-scale taxonomic inventories are need on all of the islands, particularly for non-vertebrate fauna. This should be done before any further large-scale development takes place. Second, the boundaries of Isla Bastimentos Marine Park should be expanded to include land area and mangroves directly abutting the most diverse reefs. Buffer zones should be set aside to allow indigenous communities access to the resources they need using traditional low-impact, sustainable practices, with the idea that as they develop small-scale community tourism, they will eventually rely less on these finite and unique island ecosystems. Large-scale development should be halted in areas adjacent to forest preserves and reefs, and preferably stopped altogether. New protected areas should be established on every island in the Archipelago, especially Isla Escudo. Strict zoning laws are needed to limit the kinds of development and location of development relative to critical biological resources. These measures are needed to ensure the continued function of the Bocas del Toro Archipelago as a natural scientific laboratory, and to ensure that the people of Bocas have a sustainable future.
Thank you for your consideration of these issues.
Sincerely,
Tim Billo
Doctoral Student
Box 351800
Seattle, WA 98195 USA
timbillo@u.washington.edu
Ph. 206-543-0417
Fax: 206-543-3041
Filed under: Areas Protegidas, Arrecifes, Biodiversidad, Bocas del Toro, Bosques, Decline de anfibios, Etica, Evaluación de Impacto Ambiental, Fauna, Recursos Naturales, Vida Silvestre | 1 Comment »
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