Costa Rica: Establishment of a Local Biological Corridor Through Ecological Restoration

Project Stage:
Implementation

Start Date:
2004-03-31

End Date:
2007-12-31

Primary Causes of Degradation

Degradation Description

The NSBC is located in an agricultural landscape of mostly banana plantations, plantain plantations, hearts of palm plantations, cattle raising farms and human settlements. Other important economic activities in the region are ecotourism, pineapple plantations and timber plantations. Sixteen restoration areas were identified within those properties, the areas were identified by the need for ecological restoration and because of the strategic position to develop linkages such as distance between forest fragments, shape, and other characteristics of the fragments. The previous land uses and/or disturbances to these restoration areas were the following: banana plantations; abandoned banana plantations areas already possessing secondary growth; cattle raising pastures; an area where the superficial soil layers were completely removed to be used to build a dike (the area had problems of erosion and severely compacted soils); protected areas (within the Nogal Private Wildlife Refuge) that were affected by floods from a river, Río Sucio – since these areas are bordered by a dike the flood waters remained much longer than the usual causing many trees to die and fall down fostering the colonization of invasive plants (including exotic invasive species such as Musa velutina) and also the edge effect in the remaining forests – the main stressor in these areas is therefore the floodings from the river; areas adjacent to a secondary road and along a dike where the deforestation and the work of trucks have damaged and compacted the soils. It is important to note that the main stressor of these areas is either the direct or indirect effects of flooding or its implications of anoxic conditions in the substrate.

Reference Ecosystem Description

The region has a flat topography of mostly alluvial lowlands with undulating terrain in some areas. The annual rainfall is around 3712 mm to 4000 mm with peaks in December/January and June/July. The average temperature is 25.8 ºC and the area is considered a Tropical Wet Forest according to the Holdridge Life Zone system. The soils are mostly Inceptisols and Ultisols with the former predominating near the Río Sucio margins.

Braulio Carrillo National Park extends down to La Selva through a forest corridor that descends in elevation from 2,906 meters at Volcán Barva to 35 meters above sea level at La Selva. This reserve, consisting of both La Selva’s protected environs and the Park, has four major tropical life zones and includes more than 5,000 species of vascular plants, of which more than 700 species are trees. The fauna is similarly diverse. Large predators include jaguars, pumas, and bushmasters. Thousands of arthropod species are being currently recorded at La Selva, and more than 400 species of resident and migratory birds have been sighted in the reserve, representing almost half of Costa Rica’s bird species.

Project Goals

The project intends to connect forest fragments from the Nogal Private Wildlife Refuge, a natural private reserve owned by Chiquita Brands International, to La Selva Biological Station, an ecological research station owned by the Organization for Tropical Studies (OTS). The main restoration goals of this project are the recovery of degraded and damaged ecosystems as well as the replacement of ecosystems that were entirely destroyed.

Monitoring

The project does not have a monitoring plan.

Stakeholders

In 2004 the Nature and Community Project (NCP), an effort between Chiquita Brands International, MIGROS (a swiss retailer), GTZ (German cooperation agency) and Rainforest Alliance was initiated. This project has been working on ecological restoration activities to achieve the consolidation of a local biological corridor in the northern Caribbean lowlands of Costa Rica. The NCP visited each landowner to make a proposal to develop ecological restoration activities within their properties. The most “official” agreement was made with the Monge Leon cattle raising family, a family that has owned a 300 ha (741 acres) farm for over 30 years, the linkage that goes through this property is the largest (4.5 ha = 11.5 acres). Taking into account that there is no legal mechanism to make biological corridors in the Costa Rica’s environmental laws the NCP decided to create an “honor” agreement between Chiquita and the family’s cattle raising company. Ten properties were identified to be used for ecological restoration, including a property owned by Chiquita brands International (where the Nogal Private Wildlife Refuge is located).

Description of Project Activities:
To propose and develop the NSBC through ecological restoration, the Nature and Community Project (NCP) has evaluated the landscape by using satellite photographs, a cartographic sheet and systematic field observations. As a result of analyzing the mentioned sources the NCP identified the key sites to develop physical linkages between the major forest fragments through ecological restoration activities. It is important to note that even though the objective of the NCP is to consolidate physical linkages between forest fragments through ecological restoration, primates are considered a focal group. Primates were chosen as the focal group after the results of a research study. The study analyzed monkey populations, Howler Monkeys (Alouatta palliata) and White-faced Capuchin Monkeys (Cebus capucinus), in order to explore future viability under different scenarios. The study found evidence to support greater viability for primate populations under a fully developed biological corridor fusing both forest fragments. It also found that if the refuge's two forest fragments would have been left separated from each other the monkey populations of both monkey species would not have been feasible within 16 to over 30 years. After identifying the key properties necessary to create the linkages through ecological restoration, the project identified ten small and large landowners. Thus the NCP visited each landowner to make a proposal to develop ecological restoration activities within their properties. The most "official" agreement was made for the Monge Leon cattle raising family, a family that has owned a 300 ha (741 acres) farm for over 30 years, the linkage that goes through this property is the largest (4.5 ha = 11.5 acres). Taking into account that there is no legal mechanism to make biological corridors in the Costa Rica's environmental laws the NCP decided to make an "honour" agreement between Chiquita and the family's cattle raising company. Ten properties were identified to be used for ecological restoration, including a property owned by Chiquita brands International (where the Nogal Private Wildlife Refuge is located). Sixteen restoration areas were identified within those properties, the areas were identified by the need for ecological restoration and because of the strategic position to develop linkages such as distance between forest fragments, shape, and other characteristics of the fragments. As a result of the negative impacts to the areas project leaders identified the needs for ecological restoration. The management plan for the Nogal Private Wildlife Refuge (Nogal PWR) included within its management programs to ensure the long term conservation of the reserve, the creation of biological corridors and reforestation of surrounding areas. To achieve the restoration and landscape connectivity goals the methods to manipulate the biotic and abiotic components were determined and written down in a protocol. This restoration protocol has all the methods performed by the project and has been under updating as more new methods have been practiced. The main interventions made in order to prepare the restoration areas and the maintenance activities are indicated as following: - Selection of tree species for reforestation: 46 native species were first selected between the years 2004 and 2005 for the reforestation. In the following years more species have been added to reach a total of 56 native species (to the region of the country). The following seven species are considered threatened: Jícaro (Lecythis ampla), Corteza (Tabebuia guayacan), Targuayugo (Dussia macroprophyllata), Cedro (Cedrela odorata), Manú (Minquartia guianensis), Campano (Sacoglottis trichogyna) and Almendro (Dipteryx panamensis). The main propagation methods used are seeds. To mark each tree planted a cane pole of Gynerium sagittatum was used, which is actually one of the dominant grass species in target for control. Poles were marked with different colored ribbons to identify monitored trees. - Drainages: as the flooding of the local river basin affects the trees planted the PNC made drainages in critical parts where the most intense flooding occurs. This part is in one of the forest fragments of the Nogal PWR. Other smaller drainages were made in other reforestation areas that were prone to floodings (partly because of the damaged soil conditions). - Soil mixing: in one area (area 6) the soil was significantly damaged by exploitation, erosion and compaction. Thus minimal soil mixing was done by using a truck with subsoiler, and then the soil was mixed with chicken manure. - Holes for trees and tree spacing: holes of different dimensions were dug according to the condition of the soils. For normal soil conditions holes of 15-22 cm deep and 10 cm diameter were dug. For compacted soil conditions holes of the following dimensions were made: 45 cm x 25 cm in the latter case organic fertilizer (chicken manure) was applied at the bottom of each hole. As this plantation was for ecological restoration purposes trees were not planted at equal distances. Different spacing distances were used: 3 m x 3 m, 3.5 m x 3.5 m, 3 m x 4 m, 4 m x 5 to 5 m x 5 m. For all the restoration areas a random species distribution was set. - Elimination of weeds: the main dominant weed species competing with the planted trees are mostly three: Gamalote grass (Paspalum sp.), Velvet Pink Banana (Musa velutina) and Caña brava (Gynerium sagittatum). The second is an exotic invasive species native to Vietnam. The first species, Paspalum sp., is by far the most dominant, so in order to take a more efficient control a herbicide (Roundup® by Monsanto) was used, but only in areas without any slope or near water sources to avoid contamination. - Fencing: in restoring cattle farms, fencing is vital to protect trees from the livestock damage. As part of the restoration protocol the PNC installs both dead fences (wood poles) of Gavilán (Pentaclethra macroloba) tree wood and live fences of Poró tree (Erythrina spp.), for the latter cuttings were used as propagation method. In the cattle raising family's farm three fence gates were made along the linkage so that they can move the livestock from one side of the farm to the other without having the risk of the animals entering the reforestation areas. - Relocation of electrical cables: considering that the Nogal PWR was divided into two separated forest fragments there was a need to link them especially for the viability of primate populations. However the main problem for connectivity was the location of the electric wires that were serving as a functional barrier for the linkages. The NCP decided to pay for the movement and relocation of the wires approximately 100 m away from the former site so that the trees can be planted without the need of having them heavily pruned in the future. - Soil management with fertilizers and dolomitic lime: as a result of soil analysis interpretation, for every main area organic and inorganic fertilizers were used to manage soil conditions. Soil analyses were made by the Costa Rican National University's (UNA) Institute of Forestry Services and Research (INISEFOR) and the National Banana Corporation (CORBANA). The products used include: 10-30-10 fertilizer and two organic fertilizers made of chicken manure, and of mule manure and banana waste. Dolomitic lime was used in the most critical areas. - Selective pruning and thinning of preexisting vegetation: some of the abandoned banana plantations which had secondary growth with many ephimeral heliophyte species such as: Lengua de vaca (Conostegia xalapensis), Balsa (Ochroma pyramidale), Guarumo (Cecropia obtusifolia), among others. Pruning and thinning was necessary to eliminate competition and increase growth rate of the planted species (long-lived heliophyte species). - Site clearing: the basic site preparation and maintenance in all the restoration areas consists basically of manual clearings by using a machete which was generally cutting and clearing all the grasses and weeds in the reforested area, but leaving some ecologically important species (see next point). The maintenance clearings involve clearing the weeds in a radius of 1 m around each tree planted. - Passive restoration: for all the restoration areas the project workers left the growth of certain herbs, shrubs and tree species that are vital in tropical ecosystems. That was done when they had no interference with the growth of the planted trees. Those species were mostly of the following families: piperaceae, cecropiaceae, asteraceae, fabaceae, tiliaceae, bombacaceae, anacardiaceae, among others. These species are of special importance for animal pollinators and dispersers such as bats, birds, moths and other insects. For two restoration areas plots for natural regeneration were determined (one of 2,500 sq. m and the other of 5,380 sq. m) and marked so that in the future growth can be compared between passive and active management. - Edge effect management: areas along the Nogal PWR perimeter in the forest edge were managed by clearing selected vine species (that were growing over large trees) and eliminating exotic herbs such as the Velvet Pink Banana (Musa velutina) and other preexisting vegetation. Monitoring of the reforestation has been performed every three months since the initial planting. Ten percent of all the planted trees are monitored. The sampled trees were selected in a zigzag route throughout each reforestation area, only in area 9 selection occurred with a sample of 10% per species of tree planted. The following measurements and observations are carried out in each monitoring session: height, diameter and observations focusing on the general health condition of each tree monitored. As trees grow considerably fast in the tropics, measurement methods needed to be changed in the course of the monitoring activities. For height measurements metric tapes were being used but as trees grew up quickly a telescopic metre (for trees taller than 2 m) and a Haga altimeter (for trees taller than 9 m) were used. For diameter measurements the project crew used a Caliper (0-150 mm) initially and then a diameter tape to measure DBH. Of the number of trees planted in monitored restoration areas (10,713), 9.36% of them were sampled. The total number of trees planted by the project was 15,846. The rest of the trees (5,143 trees) were planted in non-monitored restoration areas that are under proper maintenance procedures. Height measurements were taken from the very base of the tree to the base of the upper bud at the tree top of the tree. The measurements with the Caliper were taken at the base of the tree but as the trees grew in width DBH (1.3 m) measurements needed to be taken with a diameter tape. The measurements are taken by people from the community and three maintenance employees of the Nogal PWR that were previously trained. Supervision of the activities, tree health condition observations, and also measurement taking was also performed by a forestry engineer and a technician in forestry and wildlife management.

Ecological Outcomes Achieved

Eliminate existing threats to the ecosystem:
The results and the restored areas show by themselves an evident progress towards ecological restoration. The total number of trees planted by the NCP in 20 restoration areas was 15,846 although the monitoring was only done in 16 restoration areas. The total number of trees monitored is 1,484 (9.36%). The growth of tree species varies but the average growth rate for trees of all the restoration areas is remarkable but not unexpected for the lowland humid tropics of Costa Rica. It's important to note that the growth rate of area 9 (which was previously a cattle pasture) is even higher than area 3.2, an area located inside the Nogal PWR, although the latter is occasionally affected by flooding. Abandoned banana plantations (areas 4, 4.2 and 7.2) also show a high growth rate probably because of the nutrients left by the agricultural activities and/or the organic matter developed through the succession process after the abandonment of the plantations. Area 8 showed the highest growth rate, and curiously the highest mortality rate, the area was previously an abandoned pasture in a sloppy and well drained area. Most of the restoration areas have individuals (trees) with diameters ranging from 0 to 60 mm. Area 7.1a & b has the most trees with diameters ranging between 100 mm to 120 mm. The majority of trees where DBH was measured have diameters ranging form 0 to 20 cm. The competition between the planted trees and the preexisting vegetation appears to have forced the trees to grow both in height and width. Also pruning and thinning activities of the preexisting vegetation have encouraged the growth rate. The total mortality rate of all the trees monitored (n = 1,484) was 13.48%. The mortality rate was higher for areas 4 and 8 mostly because of damages caused by animals and competition with vegetation. In these areas the mortality rate exceeded 20% under which mortality is considered very high in tree plantations. The trees in the area 4 were heavily attacked by Leaf cutter ants (Atta sp.) just right after the initial plantation of the trees. Another reason that explains the high mortality rate in this area was the quality of the saplings (size of the saplings and the substrate quality), since the project bought the genetic material and it was not produced by the project's tree nursery. The main causes of mortality have been the following: damages by White-tailed deers (Odocoileus virginianus) and cows, competition by weeds and vegetation, planting trees that were too short (less than 19 cm in height), accidental cutting of the trees when clearing the sites for maintenance, damages by Stingless bees, Leaf cutter ants and attacks by Shoot-borer moth larvae Hypsipilla, and nutrient deficient soils.

Factors limiting recovery of the ecosystem:
There are only two officially protected areas in the NSBC, Nogal Private Wildlife Refuge (102 ha = 252 acres) and La Selva Biological Station (1,600 ha = 3,900 acres) which are respectively located at the northern and southern borders of the corridor. There are two other large important forest fragments within the corridor that are not being officially protected. The NSBC is also located in a working agricultural landscape of banana, plantain, and hearts of palm plantations, cattle raising farms and human settlements. Other important economic activities in the region are ecotourism, pineapple plantations and timber plantations. There are six communities that rely on the land which exist within the corridor: Nogal-Guayacán, Caño Negro, El Palmar, La Flamínea, El Tigre y La Trinidad. Flooding of the stream basin can affect recovery. As the flooding of the local basin affects the trees planted the PNC made drainages in critical parts where the most intense flooding occurs. Other smaller drainages were made in other reforestation areas that were prone to flooding (partly because of the damaged soil conditions).

Socio-Economic & Community Outcomes Achieved

Economic vitality and local livelihoods:
The management plan for the Nogal Private Wildlife Refuge (Nogal PWR) included within its management programs to ensure the long term conservation of the reserve, the creation of biological corridors and reforestation of surrounding areas. Therefore the following benefits for the ecological restoration activities were identified: - Ecological benefits: creation of a local biological corridor to conserve biodiversity in the long term; the environmental services given by these reforested areas: oxygen production, carbon dioxide fixation, hydric resources protection, etc. At least 76% of the tree species planted have known benefits for wildlife mostly as food sources and refuge. - Economic benefits: the biological corridor has the advantage of being potentially important for the ecotourism industry as well as for environmental payment services if the current system is changed in the future. - Aesthetic benefits: a reforested and linked landscape with all its wildlife is more pleasant and beautiful than a landscape where degradation and destructive land uses prevail. - Educational purposes: there is a strong component of environmental education in the region which is being achieved by the local commission of natural resources (CRENASA) an initiative that groups the main conservation organizations in the region (including the NCP). The NSBC is a great effort to educate and encourage future generations through field educational trips to the linkages and so on. - Scientific benefits: by trying to link a biological corridor to one of the world's most famous tropical ecological research centres and through an alliance with OTS the NCP is encouraging the biological monitoring of the corridor by experts from La Selva Biological Station. The ecological restoration efforts also provide impetus to other restoration efforts in the region.

Key Lessons Learned

The results and the restored areas show by themselves an evident progress towards ecological restoration. Although the restoration effort was not meant to have a fully scientific approach it is a relatively simple and sensible effort based on technical and scientific knowledge. It is also an important contribution to the local conservation efforts in Sarapiquí, Costa Rica. This effort has been an important learning process regarding the restoration methods used, the monitoring methods and the community involvement. There is a gap when it comes to ecological restoration in the Neotropics that needs to be addressed by conservationists and land managers. This project can be considered a model for future efforts in the Caribbean slope of Costa Rica and in other countries because of its relatively low costs and its potential for a social impact regarding environmental protection. Some of those trees species are not considered of commercial importance as they are not timber species giving to this effort a surplus value in the use of “unknown” native tree species for ecological restoration purposes. Soil chemical analysis and data gathered with the monitorings have been crucial to understanding growth dynamics, mortality, and factors affecting the planted trees in a very simple and matter-of-fact way. This effort also entailed the temporary employment of local people, especially young adults, some of them are high school students who attend school at night. Thus an ecological restoration project has played a complementary role in the income of the people of a rural village.

Some recommendations based on the experiences gathered during the course of this project are of significant relevance to this and other efforts:

– Trying to consolidate linkages in the landscape through ecological restoration (with the use of native species) and with the support of companies and local people can have an interesting and relevant impact that needs to be considered for land managers and conservationists.

– Ecological restoration methods such as vegetation and soil management and continuous maintenance rather than only tree planting are a must when trying to restore tropical degraded ecosystems in an agricultural landscape.

– The maintenance routines (site clearing, fertilizing, and so on) are also necessary for the development of the restored ecosystem and to guarantee sufficient resilience of the restored ecosystem in a shorter term.

– Passive restoration is very important to let ecological processes happen, considering that these processes are very dynamic and complex in tropical ecosystems. In some areas it is important to allow the growth of some herb, shrub and trees species even in the same active managed areas but bearing in mind that such vegetation might need some management to ensure that they do not interfere with the planted trees that may have a special long term importance for the ecosystem.

– The management of edge effect in tropical rainforests may have a very relevant role in ecological restoration in the future so these activities must be continued to produce some experience. But more research on this topic will be of special interest for forestry ecologists.

– It is important to train the field work staff in order to develop motivation and commitment as well as precise data. The standardization of monitoring methods needs to be well considered before the start of any restoration project.

– For the reforestation monitoring it is recommended that the standardization and the use of a bigger sample size per species and for each restoration area. Such things need to be considered before the start of the project.

Long-Term Management

Monitoring of the NSBC is ongoing and relationships have been established between numerous scientific and environmental organizations to define various future research projects. They include a detailed study of the monkey population in the area to determine their long-term viability and a study of how plants and wildlife are affected by annual floods. Another study will assess which environment wildlife prefers – induced reforestation or natural regeneration – to determine which method should be used to restore other areas.

Planting native trees within the degraded areas may have an additive affect on natural regeneration of forest areas via natural mechanisms. Researchers found that plantations of native species at La Selva Biological Station (Costa Rica) were effective in attracting seed dispersal agents from nearby forest patches, thus facilitating regeneration of degraded pasturelands. To facilitate long term conservation the management plan for the Nogal Private Wildlife Refuge (Nogal PWR) included the creation of biological corridors and reforestation of surrounding areas.

Sources and Amounts of Funding

$85,045 (related to on-the-ground restoration effo USD The cost of planting a tree (including land preparation, planting and maintenance) is US$3. But the costs are certainly higher as most of the trees still need around one to two years of maintenance in nursery care. These costs show a specific case, it is important to note that the expenses will vary from country to another and also depending on the ecosystems to be restored. Costs can include activities that are not ecological restoration activities such as training of the farmers on intensive land use with agroforestry/silvo-pastoral systems and the advice provided by an agronomical engineer. The total project costs (excluding the professional advisory costs – but including the labor force) for project years 1-3 were $85,045.

Other Resources

Chiquita. 2004. Corporate Responsibility News: Nogal Reserve Focuses on Ecology. Chiquita Vision 2: 19

Montero, J. B. 2007. Establishment of a local biological corridor through ecological restoration in the northern Caribbean lowlands of Costa Rica. Nature and Community Project Report – Chiquita Brands International, Inc. 32 pp.

Zamora, C. O. and F. Montagini. 2007. Seed rain and seed dispersal agents in pure and mixed plantations of native trees and abandoned pastues at La Selva Biological Station, Costa Rica. Restoration Ecology 15: 453-461.

Websites:

http://www.chiquita.com/naturecommunity/Home.asp
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