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Introduction
The dramatic and troubling rate of loss of primary rainforest throughout the tropics is of great concern to scientists, conservationists, land managers and concerned citizens. In many tropical areas, rainforest is converted to pasture, which is used for cattle grazing for several years, and subsequently abandoned when the soil is exhausted and no longer able to support good forage. Given the right conditions, it is likely that rainforest can reestablish on these abandoned pasture areas, thereby mitigating the loss of primary forest elsewhere. Moreover, on a time scale of decades to centuries, reestablishment of rainforest is necessary for rejuvenation of soils that become exhausted of resources after several years of pasturing. Thus, rainforest establishment in abandoned pastures is important from two perspectives, but the critical processes, and factors that might limit these processes, remain poorly known by the scientific community. It is with these concerns in mind that we began the Charral Project in the Coto Brus region of southern Costa Rica. The project is funded by a grant from the National Science Foundation, and was initiated in the summer of 1996. We have had the pleasure of working with a number of collaborators, assistants and volunteers thus far on the Charral Project: Dr. Susanne Kolb, Courtney Gale, Brian Spitzer, Augusta West, Gordon Ward, Ronald Murillo, Eric Quesada, Laura Yeung, Christina McCain, Virginia Jin, and Andy Jones. Our thanks and appreciation to all for valuable contributions!
About the background photo The background of this webpage is a substantially lightened version of a photo taken in March 2005. It was shot from our Site 2, looking toward Site 1, and shows the development of vegetation structural complexity in contrast to the surrounding pasture. A number of tree ferns are readily visible in the photo. The large forest preserve of the Las Cruces Biological Station is along the left edge of the photo.
Project Summary The long-term goal of our research project is to determine the sustainability of various land uses in mid-elevation landscapes of southern Costa Rica. We define sustainability as the long-term, landscape-scale retention of biotic diversity and soil mass and nutrient capital. Using this definition, sustainable land use preserves the potential for productive use of the landscape for many generations of Costa Ricans. However, pastures and plantations harbor lower diversity of organisms, and in steep, rugged terrain such as that of southern Costa Rica, tend to lose both soil and its nutrient capital. Therefore these land uses alone cannot be sustainable across entire landscapes. In contrast, the potential natural vegetation of our study area is tropical premontane moist forest, which has very high biotic diversity and positive net influences on soil formation and nutrient retention. Thus, the negative influences of agricultural land uses such as pastures, coffee or banana plantations, can be counterbalanced at the landscape scale by interspersed forested areas. We are working in the vicinity of the Las Cruces Biological Station in Coto Brus canton, southern Costa Rica; in this area, forest is present predominantly as small, isolated fragments of a few hectares, to a few tens of hectares. If a landscape comprised of greater proportions of forested area can be sustainable, such forest must be reestablished on some lands currently in agricultural use.
The short-term goal of our research is to characterize the rates, patterns and mechanisms of forest regeneration in mid-elevation pastures in the vicinity of Las Cruces. During the current Phase I, we are studying the vegetation of abandoned pastures where forest regeneration is occurring naturally. We have established observational areas and experimental plots in five pastures, called Sites 1 -5. All were active pastures until we fenced them in May of 1996. In these Sites, we have quantified seed rain, the seed bank (seeds stored in the soil), seed germination, seedling recruitment, and sapling growth. From these preliminary observations, we are developing hypotheses concerning the barriers to forest regeneration on abandoned and degraded pastures. We believe that our research will aid reforestation efforts in the future, specifically by identifying conditions and strategies that may limit natural or anthropogenic reforestation, and thereby by suggesting conditions and strategies that will ensure that inexpensive reforestation efforts will succeed. We will make our research available to all interested Costa Rican parties through publication and outreach programs at the Las Cruces Biological Station.
Peterson, C.J., B.L. Haines, and J.J. Dosch. Classical succession models and first-decade forest regeneration in five abandoned pastures of premontane wet forest, Costa Rica submitted to Journal of Ecology. Abstract here.
Dosch, J.J., C.J. Peterson, and B.L. Haines. 2007. Seed rain during initial colonization of replicate abandoned pastures in the premontane wet forest zone of southern Costa Rica. Journal of Tropical Ecology, 23: 1-9. Abstract here.
Peterson, C.J. and W.P. Carson. 2008. Processes constraining woody species succession on abandoned pastures in the tropics: on the relevance of temperate models of succession. chapter in edited volume, Tropical Forest Community Ecology, W.P. Carson & S. Schnitzer, editors. Wiley-Blackwell Publishing.
Jones, F. A., C. J. Peterson, and B. L. Haines. 2003. Seed predation in neotropical pre-montane pastures: site, distance, and species effects. Biotropica, 35: 219-225. Abstract here.
Peterson, C. J., and B. L. Haines. 2000. Potential facilitation of tree seedling colonization by rotting logs in southern Costa Rican pastures. Restoration Ecology, 8: 361-369. Abstract here.
Jin, V. L., L. T. West, B. L. Haines, and C. J. Peterson. 2000. P retention in tropical pre-montane soils across forest-pasture interfaces. Soil Science, 165: 881-889. Abstract here.
Haines, B., and C. Peterson. 1999. Mountain sustainable development from an ecologist’s perspective, the case of the Proyecto Charral, Costa Rica. pp. 227-232 in F. O. Sarmiento and J. Hidalgo, editors. III Simposio Internacional de Desarollo Sustentable de Montanas Andinas, AMA. Corporacion Editora Nacional, Quito.
Haines, B., and C. J. Peterson. 1998. El desarrollo sustentable in montanas desde la perspectiva de un ecologico: el case del “Proyecto Charral” en Costa Rica. Geografia Aplicada y Desarrollo 18(37): 33-42.
Mailing address:
Department of Plant Biology
2502 Plant Sciences
University of Georgia
Athens, GA 30602 - 7271
Telephone:
Department: 706-542-3732
Haines office: 706-542-1837
Peterson office: 706-542-3754
Departmental Fax: 706-542-1805
e-mail:
haines@plantbio.uga.edu
chris@plantbio.uga.edu
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