Trends in research on the possible effects of climate change concerning aquatic ecosystems with special emphasis on the modelling approach

Knowledge on the expected effects of climate change on aquatic ecosystems is defined by three ways. On the one hand, long-term observation in the field serves as a basis for the possible changes; on the other hand, the experimental approach may bring valuable pieces of information to the research field. The expected effects of climate change cannot be studied by empirical approach; rather mathematical models are useful tools for this purpose. Within this study, the main findings of field observations and their implications for future were summarized; moreover, the modelling approaches were discussed in a more detailed way. Some models try to describe the variation of physical parameters in a given aquatic habitat, thus our knowledge on their biota is confined to the findings based on our present observations. Others are destined for answering special issues related to the given water body. Complex ecosystem models are the keys of our better understanding of the possible effects of climate change. Basically, these models were not created for testing the influence of global warming, rather focused on the description of a complex system (e. g. a lake) involving environmental variables, nutrients. However, such models are capable of studying climatic changes as well by taking into consideration a large set of environmental variables. Mostly, the outputs are consistent with the assumptions based on the findings in the field. Since synthetized models are rather difficult to handle and require quite large series of data, the authors proposed a more simple modelling approach, which is capable of examining the effects of global warming. This approach includes weather dependent simulation modelling of the seasonal dynamics of aquatic organisms within a simplified framework.

Evaluation of corporate environmental management approaches: A framework and application

This article proposes a framework to evaluate corporate environmental strategies. In the proposed framework, a company's environmental risks are analyzed on two dimensions, One dimension, the endogenous environmental risks, arises from the internal operations of the company. The other dimension, the exogenous environmental risks, are determined by the company's external world: its location, its ecological setting, and the demographic characteristics of the physical environment in which it operates. Four environmental management approaches are defined as a function of endogenous and exogenous environmental risks: reactive, proactive, strategic, and crisis preventive. The framework was applied in a survey of 141 company representatives in Hungary. A relationship was sought between the a priori defined environmental management approaches based on technology and location and the companies' environmental management characteristics defined by senior managers. Variables that differentiated among the four environmental management approaches were identified and ranked. The study concludes that there is a relatively well-defined relationship between the environmental risks of companies and the nature of their environmental management approaches, Implementing a strategic environmental management approach may not be the best option for all companies - although there is a growing pressure to do so.