Integrating Agricultural Landscapes with Biodiversity Conservation in the Mesoamerican Hotspot

The major challenge in tropical land management is to meet the ever-growing demand for agricultural products while conserving biodiversity, providing critical ecosystem services, and maintaining rural livelihoods. This challenge is particularly acute in the Mesoamerican biodiversity hotspot, a region of high conservation value for both wild and domesticated species that is undergoing rapid human population growth, ecological degradation, and loss of traditional farming systems (Myers et al. 2000; Harvey et al. 2005a). Approximately 80% of the region's vegetation has been converted to agriculture, threatening biodiversity. More than 300 of the region's endemic species of flora and fauna are threatened, including at least 107 that are critically endangered (CI 2007). With continuing habitat loss (deforestation is 1.2%/year in Central America and Mexico combined; FAO 2005) and fragmentation of remaining forests, pressure on the region's biodiversity will intensify. Habitat destruction and fragmentation are not the only drivers of biodiversity loss in the region, however. Globalization of market forces, agricultural industrialization, migration, public policy, and cultural changes are driving the transformation of diverse, traditional, smallholder agroecosystems into agroindustrial systems dependent on chemical inputs and mechanization (Conway Perfecto et al. 1996; Angelsen Rodrigues et al. 2004). Besides having inadequate dimensions, most protected areas are embedded within an agricultural landscape, and existing buffer zones are inadequate to alleviate effects of fragmentation, contamination by agrochemicals, hunting, and unsustainable or illegal logging (DeFries et al. 2005). The fate of biodiversity within protected areas is therefore inextricably linked to the broader landscape context, including how the surrounding agricultural matrix is designed and managed (Wallace et al. 2005; Vandermeer et al. 2007). Protecting biodiversity while sustaining agricultural productivity, indigenous cultures, and rural livelihoods, requires a new approach to conservation, particularly in regions such as Mesoamerica, where substantial habitat conversion has already occurred. In contrast to the prevailing trend of managing protected areas and productive lands separately, we propose integrated landscape management in which conservation and production units within the agricultural matrix are managed jointly for long-term sustainability. We do not advocate agricultural intensification to spare further forest conversion (e.g., Green et al. 2005) because this approach is unlikely to have the intended outcome, for reasons discussed elsewhere (Vandermeer Matson McNeely Daily et al. 2003; Mayfield Sekercioglu et al. 2007). Landscape configurations that connect forest patches, maintain a diverse array of habitats, and retain high structural and floristic complexity generally conserve more species than landscapes lacking connectivity or habitat complexity (Benton et al. 2003; Bennett et al. 2006). In addition, agricultural landscapes with abundant tree cover serve as buffers for remaining natural areas (Wallace et al. 2005) and contribute regionally to the maintenance of important ecosystem services, such as natural pest management, carbon sequestration, and water and soil conservation (Daily 1997; Soto-Pinto et al. 2002). Within agricultural landscapes, forested and nonforested habitats contribute to biodiversity conservation. Forest fragments, riparian forests, tree plantations, and other types of remnant and introduced tree cover serve as habitats for many species, enhance landscape connectivity, and retain potential for forest regeneration and restoration (Chazdon 2003; Harvey et al. 2006a). Nevertheless, other types of land uses, such as diverse coffee agroforestry (e.g., Moguel Komar 2006), cocoa agroforestry (Rice Harvey et al. 2006b), silvopastoral systems (Harvey et al. 2005b, 2006a), and traditional agroecological land uses (such as diverse polycultures, organic farming, and swidden agriculture; Finegan Nazarea 2006). Thus, conservation of biodiversity will often be well served by policies that favor smallholders, promote diverse farming landscapes, and support dissemination of traditional practices and agroecological knowledge (Castillo maintain intact habitats, ecological communities, and ecosystem functions; buffer existing protected areas; maintain landscape connectivity; and retain landscape resilience to disturbance and climate change. The agricultural goals are to fulfill human livelihood needs, sustain yields, conserve indigenous and smallholder agroecosystems and associated knowledge and culture, diversify products, minimize reliance on external inputs, and reduce vulnerability to natural disasters and climate change. Our action agenda contains six strategies (Table 1). The first consists of working with stakeholders in a participatory approach to identify priority landscapes where action for conservation and agricultural sustainability will bring the greatest results. Numerous tools already identify areas with high conservation value and the greatest need for protection (e.g., key biodiversity areas Eken et al. 2004 and priority ecoregions [Olson Harvey et al. 2005a). Measures should be taken to mitigate these threats. For example, planting multipurpose trees on farms offers an alternative to firewood extraction from native forests (Barrance integrated fire management (including prescribed burns, establishment of fire breaks, and training in sensible fire use) reduces unintended burning of native forests (Myers 2006); and adopting organic practices and integrated pest management can reduce dependence on pesticides (Kogan 1998; Morales Taberelli Naidoo Harvey et al. 2005b). In addition, tree cover in pastures and fields confers benefits to farmers, providing products (fruit, wood, fodder for livestock), ameliorating microclimatic conditions, and increasing soil fertility (Nair 1989). Nevertheles, trees may also reduce agricultural productivity through competition for light, water, and nutrients and serve as hosts for pest species (Ong Harvey et al. 2005a) already promote the use of ecological agriculture and traditional knowledge, but these efforts need to be scaled up to cover a greater proportion of the region's agricultural lands and communities. Last, agricultural land that is highly degraded, unproductive, or unsuitable (e.g., prone to erosion or colonized by exotic species) should be reforested or allowed to regenerate naturally (Montagnini 2001; Lamb et al. 2005). Restoration goals can range from restoring soil fertility for agricultural use to establishing tree plantations or forests for timber or biodiversity conservation. Reforestation efforts should include diverse mixtures of native tree species, including species that provide resources to wildlife and species that have high timber value and provide future income to local farmers. Information on many native species that could be used in large-scale restoration efforts is available (e.g., Hooper et al. 2002; Wishnie et al. 2007). Restoration can also be achieved through natural regeneration, especially where remaining tree cover provides a source of propagules. Natural regeneration can be facilitated by fencing off areas to prevent cattle entry (Guevara et al. 2004), permitting light grazing to reduce competition from grasses on tree seedlings (Posada et al. 2000), using cattle to disperse tree seeds (Miceli-Méndez et al. 2007), or retaining isolated trees or live fences that serve as nuclei for natural regeneration (Slocum 2001; Zahawi Zbinden Pagiola et al. 2005b). Another economic tool with potential to reduce the conflict between conservation and farming is carbon financing for either enhancing carbon sequestration (e.g., reforestation, agroforestry, and improved agricultural land management) or reducing emissions from deforestation (Orlando et al. 2002; Moutinho et al. 2005). The of Costa as a of can be achieved in the the carefully forest of and forest conversion to other land uses, logging within on on either of and the for the PES that for forest conservation and 1996). is only the first are logging for of production in and in Nicaragua et al. 2003). of and environmental by systematically forest cover, and managing is critical for forest conservation. In addition, that the establishment of conservation buffer and conservation will likely encourage natural habitat conservation on lands et al. 2000; et al. 2005). The strengthening of alliances among farmers, and conservation will also promote ecologically sustainable production systems and to approaches to biodiversity conservation and food et al. 2007; Vandermeer et al. 2007). of the schemes require to with environmental such as planting trees along agrochemical and planting native vegetation along also protect farm and ensure they are working conditions, and Nevertheless, or of is often transaction costs and often and are to high levels of participation 2003; 2003). political support at all levels is needed to the strategies outlined there are positive that Mesoamerican are of the of biodiversity conservation and the need to conservation with sustainable rural Mesoamerican are of the on and have to biodiversity action that ensure protection and sustainable use of biodiversity 2005). In addition, there are many programs (e.g., and and even a for in 2005) that to some the need for reconciling biodiversity conservation and rural The have also to the Mesoamerican an to existing protected areas within and between to facilitate of plant and animal species (Miller et al. 2001). be this large-scale will require the management of the agricultural landscapes in which the protected areas are embedded and will depend on the strategies outlined in our the generally positive and promising political there is a of action on the In many the political will has not yet been into funding for implementation is and support for and is place greater attention on their for sustainable development in rural regions with resources and We for a new approach to biodiversity conservation within Mesoamerican that a focus on ecologically sustainable agriculture with existing efforts in protected areas to achieve conservation at local and levels. This new approach farmers as stakeholders in conserving biodiversity and actively farmers as to resilient landscapes that wildlife and rural livelihoods and local Our action agenda provides strategies for reconciling farming and conservation and key socioeconomic, legal, and political that could their our agenda could significant positive changes for both conservation and farming. is however. Landscapes may be degraded that conservation and restoration will be and traditional knowledge may be We therefore farmers, and other stakeholders to actively and manage landscapes to a future for both biodiversity and rural livelihoods in Mesoamerica. This by a of the on and of Landscapes of Mesoamerica by the for and by the the of and the of The working by and We are to the for the