Bøger af David Leslie Hawksworth

1 Plantation forests and biodiversity: Oxymoron or opportunity? Forests form the natural vegetation over much of the Earth's land, and they are critical for the survival of innumerable organisms. The ongoing loss of natural forests, which in some regions may have taken many millennia to develop, is one of the main reasons for the decline of biodiversity. Preventing the further destruction of forests and protecting species and ecosystems within forests have become central issues for environmental agencies, forest managers, and gove- ments. In this di?cult task science has an important role in informing policy and management as to how to go about this. So how do industrial and other pl- tation forests ?t into this? Plantation forests, comprised of rows of planted trees that may be destined for pulp or sawmills after only a few years of growth, appear to have little to c- tribute to the conservation of biodiversity. Yet there is more to this than meets the eye (of the casual observer), and there are indeed numerous opportunities, and often untapped potential, for biodiversity conservation in plantation forestry. With plantation forests expanding at a rate of approximately three million hectares per year, it is crucial to understand how plantations can make a positive contribution to biodiversity conservation and how the potentially negative impacts of this land use can be minimised. That is the topic of this book.

Conservation and biodiversity of protists The conservation of biodiversity is not just an issue of plants and vertebrates. It is the scarcely visible invertebrates and myriads of other microscopic organisms that are crucial to the maintenance of ecological processes on which all larger organisms and the composition of the atmosphere ultimately depend. Biodiversity and Conservation endeavours to take an holistic view of biodiversity, and when the opportunity arises to issue collections of papers dealing with too-often neglected groups of organisms. The protists, essentially eukaryotes that cannot be classi?ed in the kingdoms of animals, fungi, or plants, include some of the lea- known groups of organisms on earth. They are generally treated as a separate kingdom, commonly named Protista (or Protoctista) in textbooks, but in reality they are a mixture of organisms with disparate a?nities. Some authors have hypothesized that the numbers of protists are not especially large, and that many have extraordinarily wide distributions. However, the p- ture that unfolds from the latest studies discussed in this issue is di?erent. There are many species with wide ranges, and proportionately more cosmopolitan species than in macroorganism groups, as a result of their long evolutionary histories, but there are also de?nite patterns and geographical restrictions to be found. Further, some protists are linked to host organisms as mutualists or parasites and necessarily con?ned to the distributions of their hosts.