Guayacan Rainforest Reserve

 

The C.R.A.R.C. is based at its Guayacán Rainforest Reserve, which is nestled in the Caribbean foothills of northern Talamanca, near the small town of Guayacán de Siquirres. This reserve, with a total area of 49 hectares (121 acres), is located in the upper catchment basin of the Siquirres River, which is an official protected watershed known as the Zona Protectora Cuenca Río Siquirres. To date 56 species of amphibians have been documented within the Guayacán Rainforest Reserve, including several very rare and endangered species. The C.R.A.R.C. is located nine highway kilometers from the city of Siquirres, right on the National Highway 10, which leads from the Caribbean lowland town of Siquirres to Turrialba. It is easy to get to the center, being only two hours from the Costa Rican capital of San José, ten minutes from Siquirres, 45 minutes from Turrialba, and less than an hour from Puerto Limón. Access from these towns is along blacktopped highways. Sorry, there are no dusty pothole-filled dirt roads.

The original property of the Guayacán Rainforest Reserve was purchased in September of 2002. In March of 2008, we were able to purchase an additional smaller adjacent property, bringing the total size of the reserve to 49 hectares.

Prior to being purchased in 2002, the land that made up the original C.R.A.R.C. reserve had a mixture of land use. Roughly 5000 sq. meters (half a hectare) bordering the highway was planted with coffee and bananas. To the east of the coffee and bananas there was a small section of pasture, roughly 2 hectares in size, which was inhabited by four cows. Along the southern border, towards the center of the property there was an additional section of roughly 2.5 hectares of pasture. The remaining area was covered in mixture of secondary and old growth forest. After purchasing the property in 2002, the cattle were removed, along with the majority of coffee and banana plants. We immediately began the task of replanting native species of trees and herbaceous plants on much of the disturbed areas. The previous owner had a permit to log a section of forest, but we were able to obtain the property before any logging took place, and as a result save that section of forest.

The smaller property bought in March of 2008 is primarily abandoned pasture and secondary forest. There is a small strip of old-growth riparian forest along the Siquirres River. This property has some important hydrology aspects, which include two small streams, and the catchment basin of another small stream that starts near the southern boundary of the original property.

Flora and Fauna of the of the Guayacán Rainforest Reserve

In the Guayacán Rainforest Reserve two life zones are represented, that of Tropical Wet Forest, and Tropical Premontane Rain Forest (Holdridge 1967). The areas within the reserve recognized as Tropical Wet Forest are those with an altitude less than 500 m.a.s.l., whereas the areas with an altitude greater than 500 m.a.s.l. are classified as Tropical Premontane Rain Forest.

The abundant rainfall, stable intermediate temperatures, high relative humidity, and varied topography at the Guayacán Rainforest Reserve create conditions that are favorable for an astonishing diversity of flora and fauna. To date, few detailed surveys of the flora and fauna have been carried out in the region of Guayacán, but such work is needed for biological and conservation awareness. Having a low to intermediate altitude (average from 400–650 m.a.s.l.) Guayacán presents an interesting assemblage of biological diversity. At these altitudes many plant and animal assemblages of lowland and mid-elevation species overlap, and this plays a key role in the rich biological diversity of the region. More than 70 species of amphibians have been documented in Guayacán, making it the richest known site in Costa Rica for amphibian diversity (Kubicki 2008; 2016; 2017; and Kubicki unpublished).

 

Some Examples of Additional Fauna Found on the Guayacán Rainforest Reserve.

Two very rare species of scorpions have been found in the Guayacán Rainforest Reserve, Chactas exsul (above and upper right) and Tityus cerroazul (lower right). The species C. exsul was rediscovered by Brian Kubicki after nearly 50 years since its last collection. Tityus cerroazul was documented for the first time in Costa Rica in 2005.

These interesting creatures, known as velvet worms, have their own unique phylum (Onychophora). These prehistoric animals are believed to have remained relatively unchanged for millions of years. The velvet worms are restricted to scattered regions throughout the tropical latitudes of the world. Three phenotypically distinct forms have been found in the Guayacán Rainforest Reserve, and it is assumed that all three represent separate species, but unfortunately there exists very little literature regarding the identification of Costa Rican velvet worms. The above images show two of the three that have been found within the reserve. The red velvet worm (upper left), Peripatus solorzanoi, measuring up to 20 cm in length, is at times seen foraging among the mossy rocks on the edges of streams, or on the forest floor at night.   Peripatus solorzanoi was just recently described as a new species in 2010. The velvet worm to the upper right has on rare occasions been seen foraging on low-lying vegetation at night, and is believed to be an undescribed species. The third species(?) that has been found in the reserve is brown with fine darker markings; this third type of velvet worm is occasionally seen while looking through the leaf litter or searching through the organic remains of rotten logs.

The diversity of vertebrates is equally impressive. Guayacán is also well known for its diversity of reptiles, especially snakes, including many rare species such as the bushmaster (Lachesis stenophrys). Nearly 70 species of reptiles have been recorded within the Guayacán Rainforest Reserve. The reserve is also very rich in avian diversity, but thus far minimal efforts have been invested in creating a detailed bird list, nonetheless our minimal efforts have resulted in more than 200 species being documented within the reserve.

Numerous species of mammals also inhabit the reserve; among them are species such as ocelots, margays, white-faced and howler monkeys, collared peccary, sloths, tayras, olingos, and kinkajous.

Topography of the Guayacán Rainforest Reserve

The Guayacán Rainforest Reserve is situated on the northeastern edge of the Talamancan Mountain Range, and due to this location at the base of such a significant massif it has varying topography. The reserve’s overall altitude ranges from approximately 435–610 meters above sea level (m.a.s.l.). Most of the extreme variation is due to the hydrologic history of the area, with the roughest terrain being found along riparian areas such as the Siquirres River and the Ilex Stream. Even with its moderately rough terrain, much of the reserve is still easily navigable by foot due to the careful planning of our trail network.

The trail system was designed to use the contours of the reserve in one’s favor. We have built our trails using the gradual contours to the best of our ability, but there are still some sections of the reserve that will require a little sweat to arrive at. Several of the most interesting ecosystems are easily accessible.

We have built over 3000 meters of trails on selected parts of the reserve. These trails are important to reduce the impact of continuously walking through the forest.   Understory plants can be extremely fragile, and may take years or even decades to reach a mere meter or two, so avoiding damage to them through the use of trails is important. The trails were also created to facilitate moving to different sections of the reserve on the western side of the Siquirres River. The section of the reserve that is found east of the Siquirres River does not have any trail system due to attempting to limit access to this portion of the reserve and in doing so reducing potential impact on the ecosystems and species found there.

 

This photo shows the small cabin located at the forested pond site. This cabin was built completely out of wind fallen trees from within the reserve. This cabin was created for the purpose of having a place to use for shelter during the unpredictable and often rainy conditions of Guayacán. The cabin measures three meters wide by five meters long. There is an outhouse behind the cabin. The outhouse has a flushing toilet, and a running waterspout for washing purposes. Rainwater is collected from the roof and is held in a 55-gallon barrel reservoir. The photo below shows the proximity of the cabin to the pond.

Climate of the Guayacán Rainforest Reserve

Guayacán has a mild temperature range, with very little seasonal variation. The average temperatures range between a high of 26°–29°C, and a low of 18°–21°C. The diurnal temperatures can vary within the reserve depending on forest coverage. The highest temperatures are felt in the open areas on sunny days, where the increased solar energy causes higher terrestrial heat radiation. During the daylight hours there can be as much as a 5°C difference between the understory of dense forest and open areas.

The C.R.A.R.C. receives an abundant supply of rainfall due to orographic lifting conditions and convectional showers and storms. Guayacán gets an average annual rainfall of 5000–6000 mm, but I have recorded as much as 7822 mm of annual precipitation during unusually wet years (data from a rain gauge at the Costa Rican Amphibian Research Center). The area lacks a prolonged dry season. In the months of April through October strong convectional showers and thunderstorms occur with greater frequency; storms producing lightning and thunder are for the most part uncommon during the rest of the year. During the months of November, December, January, and often lasting into February the rainfall can be much more continual during events that are known as “temporales”. Cold fronts coming in from the north cause “temporales”, and their effect is directly linked to the Caribbean lowlands and slopes. The year of 2015 was unusually rainy on the Caribbean versant of Costa Rica due to the conditions caused by El Niño. During 2015 a total of 7822 mm (308 inches) of rainfall was recorded at the C.R.A.R.C. Guayacán Rainforest Reserve.

mapa2

This map shows the average annual rainfall for Costa Rica. Courtesy of I.C.E. and the Instituto Meteorológico Nacional.

The relative humidity in the Guayacán Rainforest Reserve is high, with an average range from 75–100% throughout the day and evening.

Strong Wind conditions are unusual to rare in Guayacán, but light breezes between 1–10 km/hour often occur, especially in the afternoons or during changing weather fronts.   The sections of Guayacán that receive the highest air movement are the upper ridges, where light breezes are commonly present.

Aquatic Resources of the Guayacán Rainforest Reserve

 

Due to the heavy annual rainfall in the region of Guayacán the C.R.A.R.C. Guayacán Rainforest Reserve is very rich in aquatic resources. Such aquatic resources include swampy areas, ponds, seepages, springs, streams, and the Siquirres River. Within the reserve there are 7 ponds, 16 (rivers, streams, seepages, and springs), and several swampy areas. There are more than 3900 meters of riparian habitat found within the Guayacán Rainforest Reserve. Several of the smaller streams actually originate within the reserve’s boundaries.