This thesis deals with the nature conservation of reptiles and amphibians in theNetherlands, the present practices and what should be done to improve them. Most of the species of the herpetofauna, as these groups together are known, are in a state of continuing decline. Obviously something is wrong; apart from the role played in this decline by loss of habitat, measures in the field are not effective for the sustainable survival of these species. This thesis has been written to rectify this; based on current knowledge of the ecology of these protected animals and on own experiences with nature management, it is meant to provide a guide and practical tool when carrying out the appropriate measures in the field. EN-US'>The introduction describes work that has been done internationally, especially at European level, to protect the herpetofauna. Further, how this has influenced policy plans and legislation in theNetherlands. It also points out the shortcomings, both in the approach of the policymakers, as well as in the current training of nature managers, and how these are reflected by the measures taken in the field. This information provides a background for chapter 7, the last chapter of this thesis, where the practice of management is discussed. EN-US'>The remaining chapters include five articles on ecological research; they also show how much time is needed to improve our knowledge on the ecology of these animals. Also, not understanding it can unwittingly create marginal conditions for a species, as was the case for the Slow-worm and Sand Lizard with the forest management on the Utrechtse Heuvelrug in the 1980s; this is described in the first two articles.That long-term surveys of population dynamics are more than necessary, is shown by the great fluctuations in the presence and activity of the European tree frog over the six years it was studied in the southwest of the Netherlands. Methodology is also discussed in this third article, and a practical formula given for estimating population size.Pond ...