The identification of inputs and outputs is the first and probably most important step in testing and analyzing complex systems. Following accepted natural laws such as the conservation of mass and the principle of electroneutrality, the input/output analysis of the system, be it steady or in connection with perturbations will reveal the status dynamic, will identify whether changes are reversible or irreversible and whether changing the input will cause a hysteresis response. Moreover, measurements ofinput and output fluxes can indicate the storage capacity ofa system, its resilience to...

Low temperature represents, together with drought and salt stress, one of the most important environmental constraints limiting the pro- ductivity and the distribution of plants on the Earth. Winter survival, in particular, is a highly complex phenomenon, with regards to both stress factors and stress responses. The danger from winter cold is the result not only of its primary effect, i. e. the formation of ice in plant tissues; additional threats are presented by the freezing of water in and on the ground and by the load and duration ofthe snow cover. In recent years, a number of books and...

The impetus for this volume comes from two sources. The first is scientific: by virtue of a preference for certain large benthic invertebrates as food, sea otters have interesting and significant effects on the structure and dynamics of nearshore communities in the North Pacific. The second is political: be- cause of the precarious status of the sea otter population in coastal California, the U.S. Fish and Wildlife Service (USFWS) announced, in June 1984, a proposal to establish a new population of sea otters at San Nicolas Island, off southern California. The proposal is based on the premise...

In view of the increasing problems of waste disposal in the Netherlands, plans were made to pipeline the waste to the Ems-Dollard estuary. To evaluate the practicability a project was started with the aim to implement a simulation model of an estuary ecosystem. This model was based on the knowledge of the hydrology, geochemistry and biology of the Ems estuary. For this approach data of the abiotic and biotic environment were collected in studies of the Ems estuary and are presented in this report. With its comprehensive information of biological processes as food webs, biomass production and...

The understanding of pollutant transformations, sorption and transport in soils and uptake by plants is the key to controlling contaminant movement towards groundwater and accumulation in food-chains. Some of these major processes were discussed in the first International Workshop on Pollutants in Porous Media, con- vened in Israel in 1983 (pollutants in Porous Media, Eds. Yaron, Dagan and Goldshmid, Springer-Verlag, 1984). Since that meeting, research on contaminant impact on the environment expanded considerably. New mechanisms explaining inorganic pollutant par- titioning between solid and...

This comprehensive survey comprises a documentation of the climatic and geological factors and an analysis of the natural plant communities of the sahelian ecosystems. Moreover, studies of the land-use and livestock production systems, and the primary and secondary productivity of the Sahel are presented, taking into account the various physical, biological, societal, political and economic factors influencing or constricting their development. The principles, methods and possible data interpretation for the monitoring of ecosystems are discussed, supplemented by a case study in Senegal. The...

In his lectures my teacher Karl Magdefrau used to say that one only becomes a real plant scientist when one enters a tropical rainforest. For me this initiation occurred in 1969 in northern Queensland, Australia, and was associated with the greatest excitement. On another level it received confirmation when I set out in 1983 together with some friends and colleagues for the first detailed ecophysiological studies of epiphytes in the wet tropics in situ in the island of Trinidad and later for similar work in Venezuela. This then promoted the idea of organizing a special symposium on "The...

In March, 1983 a workshop on Pollutants in Porous Media was hosted by the Institute of Soils and Water of the Agricultural Research Organi- zation in Bet Dagan, Israel. At this workshop, the unsaturated zone be- tween the soil surface and groundwater was the focal point of discus- sions for scientists from various disciplines such as soil chemists, physicists, biologists and environmental engineers. Since then, the prob- lem of soil and water pollution has only worsened as more and more cases of pollution caused by human activities including agriculture and industry have been revealed. A...

In a very real sense, much of North American physiological plant ecol- ogy began in the Basin and Range and has been researched there over the last four decades. However, we believe that this book may be the first attempt to bring together the full range of contemporary research into the fascinating plant biology of the Basin and Range Province. We have invited contributions from researchers presently working in and around the Province and asked them to review the major vegetation zones and distinctive environmental issues from a predominantly plant ecophysiological perspective. As...

In this volume experts present the latest status of mathematical and statistical methods in use for the analysis and modeling of plant disease epidemics. Topics treated are - methods in multivariate analyses, ordination and classification, - modeling of temporal and spatial aspects of air- and soilborne diseases, - methods to analyse and describe competition among subpopulations, e.g. pathogen races and - their interaction with resistance genes of host plants - assemblage and use of models - mathematical simulation of epidemics. New chapters on the modeling of the spreading of diseases in air...