Gradient Analysis Of Neotropical Montane Forests

Covers the range of natural and managed oak forests in the highlands of tropical America. Providing an understanding of ecological patterns and processes that determine the structure and functioning of these forests, this volume aims to serve as a basis for sustainable forest management and biodiversity conservation.

Neotropical lowland rain forests have received much attention in the last decade, particularly in the debate concerning biological diversity. The lowland forests have been mentioned over and over again as examples of the genetic richness of the tropical forests, and it is true that in small sample plots of, for instance, one hectare of lowland rain forest, the number of species is enormous. Lately, however, it has become increasingly clear, that the high alpha-diversity of lowland tropical rain forests is not accompanied by an equally high beta- and gamma-diversity. Montane forests, on the other hand, have been known for their richness, but when estimating their alpha-diversity by traditional methods using quantitative inventories of trees, their species richness does not equal that of lowland forests. Recent work that includes other life forms than trees, ie. epiphytes, climbers, shrubs and non-vascular plants, however, indicate that the alpha-diversity in many montane forests equals that of lowland forests. When studying the diversity patterns on slightly larger geographic scales, it has become evident that differences in species composition between localities in montane forests is tremendous - their beta- and gamma-diversities are high. It appears that, although they cover much smaller extensions than lowland rain forests, Montane forests are the homes of the better part of the biological diversity of the neotropical countries. Discussions and attention relating to conservation has been equally skewed towards the lowland forests. Still, the montane forests are just as threatened by road construction, agriculture and cattle farming as the lowland forests are. Considering this lack of attention to montane forests, despite their importance for the biological diversity of the neotropics, it was appropriate to call for a symposium addressing these issues. Much knowledge obviously exists, but often in a scattered form, and it was the intention that a symposium could bring together researchers and others with interest in neotropical montane forests, biodiversity and conservation, to exchange ideas and knowledge, and to call attention to the importance of these ecosystems for the future of genetic resources of our planet. This volume contains a selection of abstracts from the "Neotropical Montane Forests Symposium" held at the New York Botanical Garden from June 21-26, 1993. The purpose of the symposium is to document biological and ecological diversity in neotropical wet and moist Montane forests, and place it in the context with other neotropical areas. Emphasis is given to plants, with regards to taxonomic and ecological richness, threatened and conservation areas of high biodiversity and endemism, the evolution, diversity, speciation, distribution and biogeography of Andean-centred genera and families.

The importance of the Neotropics to the world's climate, biogeochemical cycling and biodiversity cannot be questioned. This book suggests that gradients are key to understanding both these issues and Neotropical ecosystem structure, function and dynamics in general. Those gradients are either spatial, temporal or spatio-temporal, where many temporal and spatio-temporal gradients are initiated by disturbances (e.g., tree-fall, landslide, cultivation). And in particular for the Neotropics, three large spatial gradients - latitude, longitude, altitude (elevation) - are of critical importance. The editor has over 30 years of experience investigating Neotropical gradients in Costa Rica, Puerto Rico, Peru and Ecuador, and has published 5 previous books on different aspects of the Neotropics. Once again he has assembled top-shelf Neotropical scientists and researchers, here to focus on gradients: their nature, interactions and how they structure ecosystems.

Until relatively recently the valuable tropical montane cloud forests (hereaf ter usually referred to as TMCFs) of the world had scarcely come under the assaults experienced by the downslope montane and lowland forests. TMCFs are not hospitable environments for human occupation, and their remoteness (except in places near Andean high mountain settlements and in the Ethiopian Highlands) and difficult terrain have given them de facto protection. The ad jacent upper montane rain forests have indeed been under assault for timber, fuelwood, and for conversion to grazing and agriculture for many decades, even centuries in the Andes, but true cloud forest has only come under ex ploitation as these lower elevational resources have disappeared. They have also been "nibbled" at from above where there have been alpine grasslands under grazing pressure. Increasingly now, however, these cloud forest eco systems are being fragmented, reduced, and disturbed at an alarming rate. It is now becoming recognized that steps must be taken rapidly to increase our understanding of TMCF and to achieve their conservation, because: their water-capture function is extremely important to society; • their species endemism is high; they serve as refugia for endangered species being marginalized in these environments by increasingly transformed lower elevation ecosystems; they are relatively little studied; yet, their value to science is extremely high; they have low resilience to disturbance; vii viii Preface and many other reasons, which will be discussed subsequently in this publi cation.

A fascinating work that provides a wealth of information on one of the world’s most biodiverse ecosystems. This is the result of investigations by almost 30 groups of researchers from various disciplines. They performed ecosystem analyses following two gradients: an altitudinal gradient and a gradient of land use intensity and ecosystem regeneration following human use. Based on these analyses, this volume discusses these findings in a huge variety of subject areas.

Neotropical lowland rain forests have received much attention in the last decade, particularly in the debate concerning biological diversity. The lowland forests have been mentioned over and over again as examples of the genetic richness of the tropical forests, and it is true that in small sample plots of, for instance, one hectare of lowland rain forest, the number of species is enormous. Lately, however, it has become increasingly clear, that the high alpha-diversity of lowland tropical rain forests is not accompanied by an equally high beta- and gamma-diversity. Montane forests, on the other hand, have been known for their richness, but when estimating their alpha-diversity by traditional methods using quantitative inventories of trees, their species richness does not equal that of lowland forests. Recent work that includes other life forms than trees, ie. epiphytes, climbers, shrubs and non-vascular plants, however, indicate that the alpha-diversity in many montane forests equals that of lowland forests. When studying the diversity patterns on slightly larger geographic scales, it has become evident that differences in species composition between localities in montane forests is tremendous - their beta- and gamma-diversities are high. It appears that, although they cover much smaller extensions than lowland rain forests, Montane forests are the homes of the better part of the biological diversity of the neotropical countries. Discussions and attention relating to conservation has been equally skewed towards the lowland forests. Still, the montane forests are just as threatened by road construction, agriculture and cattle farming as the lowland forests are. Considering this lack of attention to montane forests, despite their importance for the biological diversity of the neotropics, it was appropriate to call for a symposium addressing these issues. Much knowledge obviously exists, but often in a scattered form, and it was the intention that a symposium could bring together researchers and others with interest in neotropical montane forests, biodiversity and conservation, to exchange ideas and knowledge, and to call attention to the importance of these ecosystems for the future of genetic resources of our planet. This volume contains a selection of abstracts from the "Neotropical Montane Forests Symposium" held at the New York Botanical Garden from June 21-26, 1993. The purpose of the symposium is to document biological and ecological diversity in neotropical wet and moist Montane forests, and place it in the context with other neotropical areas. Emphasis is given to plants, with regards to taxonomic and ecological richness, threatened and conservation areas of high biodiversity and endemism, the evolution, diversity, speciation, distribution and biogeography of Andean-centred genera and families.