The reconstruction of ancient marine environments is an important task of the Earth Sciences, of great interest to geology, pure and applied, to oceanography and climatology, as well as to such fields as ecology and evolution. In principle, such reconstructions are based on the actualistic approach of "the present is the key to the past." Since the deciphering of past environmental changes, either nat- ural or man-made, has considerable bearing on planning, the past may provide a key to the future. Paleoenvironmental interpretations in the marine realm are based to a great extent on...

Nitrogen is a key element in ecosystem processes. Aspects of local and global changes in nitrogen in both undisturbed and disturbed conditions are discussed. Environmental changes caused by pollution from nitrogenous compounds and changes in landuse are also described. Organisms, plants, animals and microorganisms are all affecting nitrogen supply. Emphasis is placed on natural and anthropogenic transfer of nitrogen between ecosystems and also on the interaction of nitrogen with other bioelements.

H. REMMERT Small populations are very often discussed, but there seems to be no general overview touching all the self-evident but norma, lly simply neglected problems connected with small populations. First, there are many very different types of organisms, and as every biologist should know, the problems of small populations are very different in different types of organisms. 1. In vascular plants the problems are different from the situation in birds and mammals; in marine benthic animals or in parasites such as tapeworms the problems are different again, and in seasonal planktonic animals...

Crassulacean acid metabolism (CAM) represents one of the best-studied metabolic examples of an ecological adaptation to environmental stress. Well over 5 % of all vascular plant species engage in this water-conserving photosynthetic pathway. Intensified research activities over the last 10 years have led to major advances in understanding the biology of CAM plants.
New areas of research reviewed in detail in this book include regulation of gene expression and the molecular basis of CAM, the ecophysiology of CAM plants from tropical environments, the productivity of agronomically important...

This volume is concerned with many kinds of links between terrestrial and aquatic ecosystems. Ecological systems on land interact with water in many ways that have been treated throughout the Ecological Studies series. Volume l's chapters 16 through 18, on Hydrologic Cycles, provide background that leads directly into the description of nutrient-hydrologic interactions in Chap- ter 1 ofthe present volume. Volume 2 treats further aspects of water in forests, grassland, and crops. Volume 3 summarizes biological and environmental aspects of the whole Indian Ocean as a marine ecosystem that is...

A symposium on biophysical ecology was held at The University of Michigan Biological Station on Douglas Lake August 20-24, 1973. Biophysical ecology is an approach to ecology which uses fundamental principles of physics and chemistry along with mathematics as a tool to understand the interactions between organisms and their environment. It is fundamentally a mechanistic approach to ecology, and as such, it is amenable to theoretical modeling. A theoretical model applied to an organism and its interactions with its environ- ment should include all the significant environmental factors,...

In 1971 the International Society of Tropical Ecology and the International Association for Ecology held a meeting on Tropical Ecology, with an emphasis on organic production in New Delhi, India. At this meeting a Working Group on Tropical Ecology was organized, consisting of K. C. Misra (India), F. Malaisse (Zaire), E. Medina (Venezuela) and F. Golley (U.S.A.). The object of this Working Group was to stimulate interaction between tropical ecologists through future scientific meetings and other exchanges and communications. A second meeting of ISTE and INTECOL was held in Caracas, Venezuela...

The question "Why are there so many species?" has puzzled ecologist for a long time. Initially, an academic question, it has gained practical interest by the recent awareness of global biodiversity loss. Species diversity in local ecosystems has always been discussed in relation to the problem of competi- tive exclusion and the apparent contradiction between the competitive exclu- sion principle and the overwhelming richness of species found in nature. Competition as a mechanism structuring ecological communities has never been uncontroversial. Not only its importance but even its existence...

Environmental conditions change considerably in the course of 24 h with respect to abiotic factors and intra- and interspecific interactions. These changes result in limited time windows of opportunity for animal activities and, hence, the question of when to do what is subject to fitness maximisation. This volume gives a current overview of theoretical considerations and empirical findings of activity patterns in small mammals, a group in which the energetic and ecological constraints are particularly severe and the diversity of activity patterns is particularly high. Following a comparative...

Broadleaved evergreen forests where holm oak (Quercus ilex 1.) is almost the only canopy tree are a distinctive ecosystem of the Mediterranean Basin. Biogeographically, these forests lie between cool-temperate deciduous forests to the north and drier shrublands to the south. In a more general view, they are ecologically intermediate between these deciduous forests and humid warm-temperate evergreen forests, such as the laurisilva of the Macarone- sian islands or the broadleaved evergreen forests of eastern Asia. Holm oak forests are characterized by small-stature trees (usually 5 to 12 m...