Resumen
- - Ecological changes associated with land-use dynamics characterized. The historical trend of land use in the Pucallpa region, like most other forest-margin regions, is to convert forest to agricultural lands that often end as pastures. The current landscape is a mosaic of agroecosystems without great immediate environmental problems. However, the sustainability of the different land uses is reason for concern. Timber extraction and hunting have impoverished the forests in species. Reducing the areal extension and fragmenting will cause further gradual loss of value. The Pucallpa region has many secondary forests, most being fallow lands of slash-and-bum agriculture. Although these fallows still seem to fulfil the role of restoring soil fertility, the normal fallow time-length of 3-5 years will almost certainly lead to degradation in the long term. The young fallows provide some of the services of older or primary forests, but their ecological and economic value will further decrease as fallow periods remain short and the distance to 'intact' forest relicts increases. Agricultural land with decreased productive capacity will either be abandoned or converted to pasture. The continued conversion of land to pasture as a desirable development is questionable. Monoculture pastures lead to degradation, and even the best technological alternatives (grass-legume associations) are not permanent. The use of land for pastures in this region leaves few if any options for other uses once the land is degraded; the land's ability to regenerate its productive capacity and a diverse plant community is probably lost for many years.