The research focuses on seven dryland areas where native forests have been subjected to intense human pressure in recent decades, resulting in severe deforestation and degradation. Each of these areas is characterised by high biodiversity of international conservation importance, with many endemic, threatened species. These areas are also characterised by the presence of substantial and increasing rural populations, often including indigenous communities, who rely on native forest resources for provision of a number of forest products. The sustainable management of forest resources in these areas is therefore of key importance to the livelihood of local communities. Although the processes of forest degradation in these areas are very similar, the socio-economic and policy context varies, providing scope for comparative analysis. The seven target areas are:
1. Chiapas, Mexico. Research focuses on tropical dry forest sites along an aridity gradient: from sites receiving 800 mm of annual rainfall at 1200 m elevation in the SE extreme of the Chiapas central highlands to lowland sites receiving 500-600 mm located in central Chiapas at 350-400 m elevation. Agriculture and cattle ranching are the main activities in the region, but a considerable extent of degraded dry forest remains on hillslopes. Land tenure includes medium-sized private ranchos, ejidos and communal forest lands. A number of native tree species are sources of forage during the dry periods, and many more provide timber, firewood, fruits and other products. The region is characterized by high ethnic diversity, with many indigenous groups managing land under traditional patterns of use, including cultivation of maize, livestock husbandry and widespread dependence on natural forest resources for a variety of products, particularly fuelwood.
2. Central Veracruz, Mexico. Until recently it was thought that tropical dry forest in this area of Mexico had been completely destroyed, as a result of overexploitation and conversion to agricultural land. However, recent research has indicated that remnant areas of dry forest remain. The study is being carried out primarily in the Municipality of Paso de Ovejas (19° 17 " N, 96° 26" W, 40 m asl, area 384.95 Km2). Research focuses on the driest part of the altitudinal gradient, from 40 to 1100 m altitude over a distance of ca. 50 km. In this area, the primary land use is cattle ranching, generally undertaken on a relatively small scale by private landowners. This project is developing collaborative partnerships with a number of these landholders.
3. Oaxaca, Mexico. One of the most extreme cases of environmental degradation of drylands in Mexico is provided by the Mixteca Oaxaqueña and the Central Valley regions of Oaxaca. Main causes of degradation include high livestock density, agricultural expansion, rangeland management practices, and high deforestation rates. The area is divided into three precipitation zones: (a) more than 900 mm per year, (b) between 600 and 700 mm, and (c) less than 550 mm. The following types of vegetation are found in the study area: tropical deciduous forest, oak forest, pine forest, grassland, and shrublands. In the Mixteca (2 million hectares), plant cover may be less than 25% with dispersed patches of shrubs growing on the top of knolls, and soil erosion is as high as 59% of the area with a soil loss rate of more than 50 ton ha-1 year-1. The area is populated by indigenous groups (Mixtec) whose livelihoods are primarily based on traditional forms of agriculture and use of natural forest resources.
4. Central Valley, Central Chile. Research focuses on three areas within the central zone of Chile, in the Central Valley between the Andes and coastal mountain ranges, at the transition zone between Mediterranean sclerophyllous forest and deciduous dry forest (between 35º and 38ºS, an area of approx. 60.000 km2 in extent). This area has a Mediterranean climate, and has a very high level of endemism among plant species (approx. 47%), but is also the area of Chile with the highest population density (11 million people), concentrated in the largest cities of the country. In addition to urban development of this area, another major factor responsible for the loss of dry forest is the establishment of extensive areas of plantation forests comprised of exotic species, principally Pinus radiata (extending over 2 million ha). Two of the most important uses of forest resources by local communities are extraction of fuelwood from native tree species, and extensive livestock husbandry.
5. Coastal range, Central Chile. Activity takes place in two main areas: (i) Coastal range in Valparaiso Region; 33º S, 71º 30’ W, with precipitation ranging from 100 to 800 mm. Vegetation is sclerophyllous forest, characterised by a high endemism and the presence of some xerophytic plant species such as Cactus spp. The land use is agriculture, urban areas, fruit cultivation and mining. The soil is highly degraded as a result of erosion caused by forest clearance. This region is characterised by the presence of large exporting industries of wine which has led to substantial land use changes. Also, large areas have been converted to forest plantations of exotic tree species. (ii) Eastern slope of the coastal range in the Maule region (south-central Chile). 35º 30’S, 71º 50’ W. Here, sclerophyllous forest has been widely cleared for cultivation of crops and pasture and to produce fuelwood. In recent decades there has been rapid expansion of commercial plantations of pines and eucalypts. Most of the remaining forest is owned by small and medium private landowners as well as large pulp companies, with whom the project will collaborate.
6. Northwestern Argentina. This project focuses on subtropical seasonally dry forests (SSDF) located in Salta (San Martin and Oran Departments) and Jujuy (Santa Barbara and Ledesma Departments) Provinces, northwestern Argentina (22°−24° S, 63.5°−65° W). These forests are located 350-750 m above sea level, and include Andean premontane forest and the transition to dry Chaco forest. Highly seasonal, premontane forest harbors the highest proportion of deciduous species of South America. Chaco forest is the largest unit of tropical dry forest in the Neotropics, extending through Argentina, Bolivia and Paraguay. SSDF are largely threatened by deforestation and transformation to agriculture, mainly for sugarcane and soybean crops. Timber activities are also economically important in the area, and are largely restricted to selective logging of about a dozen valuable native species. The study area covers approximately 10.000 Km2 that combines highly profitable agricultural activities with local and indigenous communities living in extreme poverty. The study area harbours the highest concentrations of ethnic groups (nine) of Argentina (from Andean, Amazonian and Chaco origin). Forest transformation for agriculture is breaking historic forest continuity between Andean premontane forest and dry Chaco forest, creating an agricultural gap of about 5 to 25 Km wide. In the study area, SSDF cover approximately 7500 Km2, most of which is highly disturbed and susceptible to transformation.
7. Southwestern Argentina. The study is conducted in the forest-steppe ecotone on the eastern slopes of the Patagonian Andes, Argentina, between 39°30' and 43°35' S. Climatically, the region is characterized by an abrupt W-E decrease in precipitation due to the orographic effect of the Andes. Droughts in concert with natural and anthropogenic ignition sources determine that fire is the main driver of ecological change in this region. High fire frequency during aboriginal and European settlement eras has led to forest fragmentation, local extinctions of fire-sensitive arboreal taxa and/or retraction of these into fire-free rocky refugia where low fuel loads have permitted the survival of scattered remnant trees. Treeless areas have been traditionally viewed by foresters and land managers as barren lands unable to support native forest and have been used for extensive sheep, cattle and goat ranching. In addition, other introduced herbivores such as European hares, rabbits and exotic deer are negatively impacting native arboreal vegetation. Another source of degradation is the current increasing trend of establishment of exotic (mostly pine) plantations, which drastically change fire regimes increasing fire extent and severity thus further negatively impacting dry native forests.