Establishing living fences in the deforested areas of Ometepe, Nicaragua in an effort to provide corridors to forest fragments for seed dispersing primates: white-faced capuchin monkeys (C. capucinus) and mantled howler monkeys (A. palliata).



Abstract:

Volcán Maderas is made up of a seasonally wet/dry tropical forest. Two primate species are native to the area: mantled black howler monkeys (A. palliata) and white-faced capuchin monkeys (C. capucinus). Both species traditionally act as germinators and seed dispersers in their ecosystems (Wehncke et al.. 2004). Forest fragmentation by agriculturalists in the area have cut off corridors used by both species, leaving large forested areas without either primate species. This has caused a lack of seed dispersal in the ecosystem and is having a profound effect on the other species which rely on the seed dispersers to maintain the ecosystem they have adapted to (Offerman et. al. 1995). The following project proposes to replace the fence posts, which traverse the deforested areas, with gumbo limbo trees (B. simaruba) to hold the fencing material; thus, providing the two arboreal primate species corridors through the deforested areas.


Introduction:

The Maderas Rainforest Conservancy currently manages approximately 10 square kilometers of tropical forest on Volcán Maderas, Nicaragua. Roughly 1/3 of this land has been fragmented due to agriculture, with pockets of forest fragments interspersed throughout the disturbed area. These deforested regions are transected approximately every 60 meters by fence lines. Each fence line traverses an entire deforested area, connecting forest fragments. This forest is home to an array of flora and fauna (Gillespie 1994), including such species as mantled howler monkeys (A. palliata) and white-faced capuchin monkeys (C. capucinus) who act as seed germinators and dispersers in the ecosystem (Wehncke et al. 2004).

Primates fulfill an important ecological niche by germinating and dispersing seeds (Poulson et. al. 2001). Both C. capucinus and A. palliata have proven to be a major cornerstone of their habitat’s ecology by seed dispersal. Forests rely on these species to maintain the biodiverse flora depended upon by the other species in the habitat (Wehncke et. al. 2004).  Many fruit bearing trees, such as fig trees, depend on these species for germination (Serio-Silva  et. al. 2002). Fragmentation has been shown to keep these species from large portions of the forest they would normally occupy (Estrada et. al. 1996). These two arboreal seed dispersing species lose access to large forest fragments, surrounded by deforestation. Neither C. capucinus nor A. palliata will traverse large areas on the ground. Hence, when an area is surrounded by deforestation, no matter how large, neither of these species will have access to it; or, the opposite occurs, where a group of primates is trapped in a forest fragment too small to provide a year round habitat. Therefore, the seed germination and dispersal, which should be occurring in the ecosystem, does not exist in the fragments. The fragments are then unable to handle the biodiversity they once housed. When a forest loses a seed dispersing species, other important species, such as decomposers are effected. Dung beetles have been shown to form a symbiosis with Howler monkeys and decrease in numbers relative to a decrease in howler numbers (Estrada et. al. 1999). Thus, an ecological chain reaction occurs in these fragments, transforming them into areas of disturbed growth rather than the tropical forests they once were. Such occurrences are evidenced in these forests (Illes 2005).

An economical and immediate solution to this issue, which does not require land acquisition or large scale replanting (both of which would be long term goals), is to replace existing fence posts in the deforested areas with trees which can hold the fencing wire just as effectively. These trees act as a “living fence” and provide arboreal species a corridor through the deforested regions. Living fences have been show to be effective in this way of providing arboreal travel routes across deforested regions and providing species, who act as seed germinators and dispersers, access to forest fragments (Estrada et al. 2006).  These deforested regions are currently divided into agricultural sections by fence lines, which transect the entire deforested areas at spaced intervals. These fences consist of wooden posts strung together with barbed wire. The same can be accomplished by planting live trees to act as the fence posts. These trees can replace fence posts and provide necessary corridors for the primate species to travel through in order to reach uninhabited forest pockets cut off by the fragmentation (Beer 1987).

The reintroduction of these species into forest fragments by live fence planting has been shown to restore these disturbed areas at a relatively rapid rate (Zahawi 2005). Such success depends on the willingness of the arboreal primates to use these living fences as corridors. Arboreal primates, especially cebids, can be suspicious and elusive of any areas of human disturbance. However, the success of live fence planting has been documented in other areas with cebid monkeys. C. capucinus, in particularly, have successfully been reintroduced into forest fragments across deforested areas (Williams et al. 2001).

Ometepe island, one of the world’s largest freshwater islands, is a key conservation target. The tropical forests on Volcán Maderas provide a unique and biodiverse ecosystem (Garber et al. 1999). This ecosystem provides such conservation foundations (among others) as: a stronghold for C. capucinus and A. palliata, a cloud forest, an important pan-american migrating bird site, and a habitat for several endangered reptiles and amphibians - all of which depend on the delicate and balanced ecosystem of the tropical forest for survival. A key component to maintaining the balance of the ecosystem is to ensure the access of seed dispersers into all forested regions.



Methodology:

The initial land for the living fence project is under the management of the Maderas Rainforest Conservancy, under the permission of the land owner. The owner has agreed to allow fence posts transecting the agricultural areas of the land to be replaced with living fences. These deforested agricultural areas account for approximately 1/3 of the total land area (approx. 10 sq. kilometers) managed by the conservancy, with fence posts transecting the clearings at 60 meter intervals.


Developing a strategy through mapping:

The first step is to prioritize which fence posts should be replaced first. This will be done strategically, by studying the home range of the monkeys. Since GPS technology has proven to be effective in mapping and tracking primate home and day range (Tsujj et. al. 2004), handheld GPS units will be used to ascertain exact UTM coordinates so that forest fragments and primate ranging patterns can be marked in detail.

First, the fragmented areas versus densely forested areas must be marked and scaled. This should provide a view of forest pockets surrounded completely by fragmentation. After this, the objective will then be to track both primate species to get an idea of their travel patterns and day ranges on the island. Again, the use of handheld GPS units and UTM coordinate mapping will be employed. The information here will shed light as to which fragmented areas are so severe as to prevent the monkeys from traversing the areas and which fragmented areas allow for primate passage. Since the Howler population is far more habituated than the capuchin population, it is well expected that the fragmentation will effect each species differently in terms of severity.


Cultivating tree cuttings in a greenhouse:

A greenhouse will be constructed on the land to cultivate trees for the fence line plantings. Both species make use of gumbo limbo trees (B. simaruba) for habitat and travel (Francis 1990). Because of this and the ability to clone gumbo limbo from cuttings as well as its rapid growth rate, B. simaruba will be the species employed for fence planting.

In order to clone B. simaruba, branch cuttings will be taken from area trees. These branches will be approximately 2 inches in diameter and will serve as trunks for the cloned trees. These will be brought back to the greenhouse and cultivated for one year. After this time, the new trees should be thick enough and string enough to plant.

In order to ensure strong enough trees and a satisfactory success rate in cloning these trees, a controlled environment is imperative. Thus, a greenhouse must be used. The controlled environment of a greenhouse will accelerate the growth rate of these trees and cultivate a stronger root system. This will also protect the new trees from area pests.


Fence line planting:

One the new trees have developed a thick trunk and strong root system, them will be planted alongside the old fence posts and allowed to root to the ground and grow. After they have been firmly established, the process of fencing can begin. Fencing wire will be attached to the trunks, creating an identical fence to what the old fence posts had housed. Once this has been accomplished, the old fence can be removed. The area is now left with a fence which accomplished everything the old fence had; yet, can be used as a corridor for primates - connecting forest fragments together.


Maintaining the living fence:

The living fence must be monitored to ensure that the trees continue to flourish. In order for the living fence to be effective, the trees must create a constant canopy line from one forest fragment to the other. Thus, the fence lines must be checked for maintenance. In addition to this, the greenhouse will continue to cultivate replacement trees in the event a living fence post is destroyed.

The fence wire must also be monitored and adjusted with the rate of tree growth. This should also be done to ensure that the wire is not harming the tree.


Recording data on primate interaction with the living fence:

After the living fence has been established, both primate species must be watched in order to ascertain the effectiveness of the new corridors. It is, however, important to note that both species may be effected by observer presence. Therefore, every effort must be made to ensure that these observations do not interfere with the primates using these structures.


Recording botanical data:

A botanical survey must be done both before the primates have access to forest fragments and after the corridors have been established. This will give insight into the seed germination  and dispersal process and will provide data as to the role of these species in an ecosystem. This will also monitor the effectiveness of the project.


Information sharing:

Throughout this project, data will be taken to ascertain the effectiveness of each phase of the project. Each phase will be written as a scientific article and submitted to academic journals for publication. These articles will answer questions relevant to reforestation projects as well as primate conservation and ecology. Such articles will include: the methodology and effectiveness of living fence planting; re-introducing a primate species to a previously fragmented ecosystem; how specific primate species build ecosystems through seed germination and seed dispersal; how forest fragmentation effects a primate group’s day range; and an overview of a reforestation strategy. It is the hope of the conservancy that these articles can provide reference to and inspire similar reforestation projects and primate conservation efforts.



References:


Beer, J. (1987). “Experiences with Fence Line Fodder                Trees in Costa Rica and Nicaragua”. in Advances in         Agroforestry Research. ed. Beer, J., Fassbender, H., Heuveldop, J. CATIE: Turrialba.


Cortes-Ortiz, L., Rodriguez-Luna, E., Miller, P. (1996). “Analysis de Viabilidad de Poblaciones y de Habitat para (Alouatta palliata mexicana)”. Neotropical Primates, 4(suppl.):134-142.


Estrada, A., Coates-Estrada, R. (1996). “ Tropical rain forest fragmentation and wild populations of primates at Los Tuxtlas, Mexico”. International Journal of  Primatology. 17:5.


Estrada, A., Anzures, A., Coates-Estrada, R. (1999). “Tropical rain forest fragmentation, howler monkeys (Alouatta palliata), and dung beetles at Los Tuxtlas, Mexico”. American Journal of Primatology. 48:4:253-262.


Estrada, A., Saenz, J., Harvey, C., Naranjo, E., Munoz, D., Rosales-Meda, M. (2006). “Primates in Agroecosystems: Conservation Value of Some Agricultural Practices in Mesoamerican Landscapes”. in New Perspectives in the Study of Mesoamerican Primates. ed. Estrada, A., Garber, P., Pavelka, M.S., Luecke, L. Springer: New York.


Francis, J. K. (1990). “Bursera simaruba (L.) Sarg. Almácigo, gumbo limbo”.  SO-ITF-SM-35. New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station. 5 p


Garber, P.A., Pruetz, J.D., Lavallee, A.C., Lavallee, S.G. (1999) A Preliminary Study of Mantled Howling Monkey (Alouatta palliata) Ecology and Conservation on Isla de Ometepe, Nicaragua”. Neotropical Primates 7:4:113-117


Gillespie, T. W. (1994). “A Biogeographical and Cultural Ecological Assessment of Nature Reserves on the Island of Ometepe, Nicaragua”. Master’s Thesis. California State University. Fullerton.


Illes, L.I. (2005). “Mantled howler monkeys (Alouatta palliata) in a fragmented habitat on the Isle de Ometepe, Nicaragua”. Dissertation. California State Uniersity. Fullerton.


Offerman, H.L., Dale, V.H., Pearson, S.M., O’Neill, R.V., Bierregaard Jr., R.O. (1995). “Effects of forest fragmentation on neotropical fauna: current research and data availability”. Environ. Rev./Dossiers environ. 3(2):191-211.


Poulsen, J.R., Clark, C.J., Smith, T.B. (2001). “Seed dispersal by a diurnal primate community in the Dja Reserve, Cameroon”. Journal of Tropical Ecology. 17:6:787-808.


Serio-Silva, J., Rico-Gray, V. (2002). “ Interacting effects of forest fragmentation and howler monkey foraging on germination and dispersal of fig seeds”. Oryx. 36:3:266-271.


Tsuji,Y., Takatsuki, S. (2004). “Food habits and home range use of Japanese macaques on an island inhabited by deer”. Ecological Research. 19:4:381-388.


Wehncke, E.V., Numa Valdez, C., Dominguez, C.A. (2004). “Seed dispersal and defecation patterns of Cebus capucinus and Alouatta palliata: consequences for seed dispersal effectiveness”. Journal of Tropical Ecology. 20:535-543


Williams, H.E., Vaughn, C. (2001). “White-faced monkey (Cebus capucinus) ecology and management in neotropical agricultural landscapes during the dry season”. Revista de Biología Tropical. 49:3-4


Zahawi, R.A. (2005). “Establishment and Growth of Living Fence Species: An Overlooked Tool for the Restoration of Degraded Areas in the Tropics”. Resotoration Ecology 13:1:92-102

 

Below are detailed descriptions of some of our current conservation initiatives. These initiatives are funded by grant support and private donations. Funds are desperately needed to ensure the success of these projects. If you wish to help, the link below will bring you to our paypal donation site. If you wish to have your donation go directly towards a specific initiative, please let us know in the comment field. All donations to the Maderas Rainforest Conservancy are tax deductible, as the Maderas Rainforest Conservancy is a non-profit, tax exempt  501(c)(3) organization. Thank you for your support!

Click to Contributehttps://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=5135224

1. Primate Corridors in the Forest of Volcán Maderas.


2. Reforestation of Pasture Lands in             La Suerte, Costa Rica.

La Suerte, Costa Rica is in a tropical rainforest basin. The area managed by the Maderas Rainforest Conservancy is one of the few surviving forest fragments in the area. The fragment itself is large enough to sustain the ecosystem within. However it has been bisected by a large pasture, making two forest fragments. The Maderas Rainforest Conservancy is working to reforest this area. Tree are being cultivated in a greenhouse at the site to plant in the pasture area. These trees are the future of one continuous La Suerte rainforest.


Students at the La Suerte field station along with members of the local communcity are helping this process by planting the trees from the greenhouse in the pasture.


Once this process is completed, animals such as the arboreal primates will be able to move between the two forests and a greater preservation of the ecosystem will be ensured.