The populations of Rana arvalis Nills. 1842 from the Ier Valley (The Western Plain, Romania): present and future

The objectives of the current study were to identify, in detail, the distribution of the largest moor frog populations from the Ier Valley region and to assess the zones that represent important habitats and present measures for their protection. Our study was conducted from March to October during the years 2001-2003. We identified 49 populations of Rana arvalis in The Ier Valley area. Most of these populations can be considered distinct, isolated from each other, apart from a few exceptions. This fact increases their regional chance of extinction. The Rana arvalis populations in the studied area occupy very different habitats. Only a few of these habitats can be considered natural biotopes. As a result of intense dry out of the swamps in the Ier Valley area, the populations of Rana arvalis had reduced in atypical smaller sized habitats, which had a limitating effect on the size of these populations. Small numbers of moor frogs were found in most sites surveyed (less then 6 specimens / site / visit) in the region. We were able to calculate quantitative population assessments for five populations. The largest population was found near Andrid, with 675 ±57 adult specimens, making this one of the largest known population of Rana arvalis in Romania. The second significant population was estimated to be 354 ±25 individuals and it was located near Resighea. The other populations’ sizes were estimated at fewer than 200 adults. We consider the protection of the large breeding populations of Rana arvalis in the Ier Valley area to be a priority, by managing both the breeding and foraging habitats. The potential for the biggest moor frog populations to be part of a single infrastructure is discussed.