Chapters authored
Thoughts on Water Beetles in a Mediterranean Environment
The chapter provides data from a survey carried out on water beetles in various freshwater ecosystems in Tunisia as a Mediterranean country of considerable diversity. Studies dealing with these insects are fragmentary not only in comparison with the European fauna but also in comparison to other zoogeographical areas. A compiled checklist of beetle species collected from Tunisia is given with an insight on new recorded species. Diversity, altitudinal distribution, and geographical pattern of water beetles in Northern Tunisia are discussed with regard to other Mediterranean areas. They include various chorotypes related to the history of the Mediterranean basin. Several species are threatened and require conservation. According to the criteria of the IUCN, several water beetle species can be included in the list of threatened species.
Part of the book: Insect Physiology and Ecology
Effect of Heavy Metal Pollution on Invertebrates
Metal pollutants are widespread in air, soil and water causing a decline in invertebrates worldwide. The increase of environmental pollution by heavy metals has a negative impact to organisms and influence their diversity, distribution, physiology and behavior. Contrary to other pollutants, metals are non-degradable and can potentially bio-accumulate and be biomagnified in the trophic chain. Because soil invertebrates tend to be strongly affected by environmental disturbances, high concentrations of these metals can become hazardous to invertebrates. Noxious effects can affect all biological levels, and toxins affect all ecological interactions. In this brief chapter, we have tried to develop a comprehensive understanding of the influence of metal contamination on ecosystem disturbance. We give examples of studies on the effects of pollutants on invertebrates.
Part of the book: Heavy Metals