Puerto Rico Critical Wildlife Areas - Puerto DRNA - Gobierno de ...

66- Mona Island, Puerto Rico
Area Description:
Mona Island is located in the latitude 18 0 3-8’N and longitude 67 0 51-57’W; 68 km to
the southwest of Higüeras tip (Rincón municipality); 74 km to the southwest of Mayagüez; 48
km to the southwest of Desecheo Island and 60 km to the southeast of Espada tip in Dominican
Republic. Mona Island has an area of 5519 ha and contains 32.2 km of coast. Due to the location
of Mona Island and the dangerous crossing of Mona Channel, the intervention of man has been
minimal. This condition has propitiated to the conservation of fauna endemic to the island
This semi-arid island is a karst plateau made up of stratified limestone and dolomite
rocks with an elevation between 40 to 60 m above sea level. The majority of the coastal zone
area is composed of cliffs. Near the surface periphery of the cliffs there is an area of 60 to 80 ha
of caves. Numerous karst features, including a series of flank margin caves, literally ring the
periphery of the island (Frank et al., 1998). In the late 1880s and early 1900s, ~150,000 metric
tons of guano were commercially mined from caves on the island (Frank and Benson, 1998).
Mona island contain 7.2 Km of sandy beaches located in the southern half of the island
(Diez and Van Dam 2004). The beaches of Mona are whiter than those of Puerto Rico (JCA
1973). The average precipitation is 79 cm per year. The soils are sandy and alkaline with low
fertility (Morales 1985; Cardona and Rivera, 1988). There are no rivers in Mona Island. There is
a very small patch of a mangrove swamp, about 0.5 ha in size. This area serves as habitat for
birds and crabs. It is under brackish water and is covered by a thick growth of mangrove trees
(Rivera, 1973).
The fauna of Mona is the most unique of any of Puerto Rico’s islands (Raffaele and
Duffield 1979). From the point of view of animal distribution (terrestrial or inland) Mona Island
can be divided into the following ecosystems: 1-Rocky shores 2-Sandy beaches 3-Coastal plains
(terrace) 4-Bajuras (sinkholes) 5-Caves 6- Limestone tableland 7-Temporary pools and water
reservoirs (Vélez 1973).
In spite of Mona’s small size, distance from a large land mass and its low rainfall, it
supports a known flora to date of 393 vascular plant species. Mona’s flora in the most part is
similar to Guánica forest plus a touch of Dominican Republic flora. The distribution pattern
shows that 25 species are unique. Four are found only on Mona; sixteen have migrated west
only to Mona and not beyond, and four species have migrated east to Mona and not beyond.
Approximately eleven percent of the flora is either rare or endangered (Woodbury 1973).
Ownership/Protection:
Mona Islands is publicly owned. The Government of Puerto Rico, through the DNER,
owns and manages both Mona and Monito Islands as wildlife reserves (Morales 1985). With a
permit obtained from the DNER, the public is allowed to visit Mona Island. During the hunting
season on Mona Island, the public (with permit and license) is allowed to hunt pigs and goats.
Special Recognition:
In 1919 Mona was declared an Insular Forest (Naturaleza 1991). It is recognized as a
“Unique Natural Area” according to the outstanding natural wonders, the scenic values and
scientific importance (JCA 1973). In 1975 was recognized as a National Natural Landmark by
the U.S. National Park Service. In 1985, Mona Island was declared Critical Habitat for the
Mona Boa, Mona Iguana and the beaches were declared breeding area for the Hawksbill sea
turtle. The Puerto Rico Planning Board declared Mona and Monito including the water that
surrounds these Islands until an extension of 3 nautical miles a Natural Reserve in 1986. The
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