Protection of Emys orbicularis and amphibians in the North European lowlands (LIFE05NAT/LT/000094)

Protection of Emys orbicularis and amphibians in the North European lowlands
Habitat managment

1. Pond restoration / digging

Most of the populations of Emys orbicularis have become fragmented, and only single isolated populations have remained in Poland, Lithuania and Germany due to the disappearance of suitable pond complexes. The restoration of existing specific ponds for all three species is necessary in order to stop the decline of the existing Emys orbicularis, Bombina bombina and Triturus cristatus populations, to increase the number of individuals and to restore the viable populations. In order to optimise conservation efforts, the creation of clusters of various ponds for all three species is needed and this complex of ponds will provide maximum benefit for the conservation of the species and for biodiversity. It is also very important to create corridors between local populations with ponds which facilitate individual exchange and support the recolonisation of habitats with extinct populations.

The restored and new ponds will provide favourable foraging, hibernation, resting and breeding (for amphibians) conditions not only for Emys orbicularis, Bombina bombina and Triturus cristatus but also for other amphibian species in need of sun-exposed breeding ponds with good water quality, such as Hyla arborea, Pelobates fuscus and Rana arvalis.

2. Improvement and creation of nesting areas for turtles

Across the countries of Lithuania, Poland and Germany, Emys orbicularis is approaching extinction in a large number of areas. The restoration of existing Emys orbicularis nesting areas, and the creation of new ones in all project areas is vital for the preservation of the species in Lithuania, Poland and Germany. Consequently, it is important to improve nesting areas in the areas, as suggested in this project.

The improvement of the status and the number of suitable nesting areas in local populations is necessary in order to prevent a further decline in the existing Emys orbicularis populations, to secure maximum breeding success, and to increase the number of populations and their viability. Reproductive success has not been recorded over the past few years in many locations with known Emys orbicularis populations in Poland and Germany. Incubation conditions should be improved in these areas if the species is to be preserved. In many cases it is necessary to free the areas from bushes, trees (mainly pines) and high density grass in order to secure open areas. On each site there must be several nesting areas connected to a cluster of ponds. In order to reduce the high predation rate on nests (up to 90 %), which harm small populations especially, the nesting areas have to be fenced or their nests have to be protected with nets. Therefore reproductive success will clearly be increased and the population size respectively.

3. Creating hibernation sites for turtles and amphibians

Hibernation sites for Emys orbicularis are in the aquatic habitat and thus the hibernation sites must be created during the digging of ponds. Hibernation sites for Bombina bombina and Triturus cristatus and other amphibians will be created in the areas around the key ponds. The hibernation sites will be made up of stone piles mixed with soil and heaps of branches in such a way that there will be plenty of holes for amphibians to crawl in. These sites can also be used as a daily refuge.

In the northern part of its distribution, Emys orbicularis spends at least half of the year, and therefore half of its life at hibernation sites. A lack of suitable hibernation sites forces turtles to choose unfavourable sites. Sites with inadequate oxygen availability and/or a high risk of frost can be a danger for turtle fitness and survival. Consequently, unfavourable hibernation sites decrease the survival rate of Emys orbicularis and the viability of small populations. The hibernation sites of amphibians are essential in order to prevent the core part of the amphibian population from migrating far out

4. Installing a sustainable grazing regime with a hardy grazer

Cattle are one of the most useful methods of anaging vegetation in the Lithuanian project sites. In some of the Lithuanian areas with Emys orbicularis and Bombina bombina it is planned to establish permanent, extensive grazing lasting a whole year. For wet areas it is useful to graze with cattle, because cattle grazing usually provides a variable sward when stocked at low to medium densities.

For Emys orbicularis its is important to keep a mosaic landscape with some open parts in order to give the Emys orbicularis a wide choice of potential sun exposed egg laying sites. The aquatic habitat cannot grow over with tall bushes and reed on the edges. Encroachment of larger plants, particularly reed and/or bulrush (Typha latifolia) will occur in shallow water bodies and must be controlled if the open water is to be maintained. The grazing of animals will secure that there are always open pond banks where turtles can sun bask. In free sunny water bodies higher water temperature exists together with lush vegetation structures and better food resources, which supplies more suitable conditions for Emys orbicularis especially during spring time and for juveniles.

5. Removal of unwanted vegetation

The Removal of unwanted vegetation such as bushes and trees near water bodies and in meadows in man's controlled landscape is an ordinary action and at the same time it is very important for the project success. Without natural grazers (aurochs, dears and roes) ponds are overgrowing and become unsuitable for many species and especially for Emys orbicularis and Bombina bombina. Installing of cattle grazing in the area can prevent from the overgrowing of ponds and meadows in the future but it cannot improve the habitat enough for being colonised by Emys orbicularis. Thus, the removal of unwanted vegetation is a necessary action and will take place in all project areas in Lithuania, Poland and Germany.

Bush cutting is important to keep three species (Emys orbicularis, Bombina bombina and Triturus cristatus) in one place. To keep slopes of ponds open to the sun as turtle basking places is one of the basic requirements for turtle ponds. From other hand, open slopes and water edge with low vegetation are good for Bombina bombina' as foraging ground. Removing of the unwanted vegetation is important in order to keep the pond water surface open, this important for tadpole development and Triturus cristatus larvae development. A more diverse fauna and flora develops in sunlit sites.

6. Rearing of turtles

In Germany and Poland, eggs of threatened nests (e.g. nests on fields, in shaded areas or those that are a long distance from the nearest water bodies) will be taken to a rearing station and incubated further if necessary. The Polish juveniles will be kept over the first winter without hibernation, while the German juveniles will be kept for two years (or three years) and fed with special food. This kind of German rearing includes hibernation time for the young turtles during wintertime. In order to secure appropriate care for the animals, they will be under the control of an animal keeper.

In order to support the increase of population size in small populations (< 20 adults), to guarantee the reproductive success of small populations and to release animals for recolonization of the habitats of extinct populations, rearing of juveniles during their first two or three years of life for increasing the total number of turtles is the best and most effective method. By taking eggs from threatened nests, the loss of hatchlings can be clearly diminished.

7. Management of foraging habitats

Emys orbicularis searches for food in moist habitats. Bombina bombina and Triturus cristatus need terrestrial or moist habitats for foraging migration. In the North European lowlands, Emys orbicularis prefers to forage in flooded areas and ponds with shallow water, and to migrate in moist habitats. Bombina bombina, especially juveniles of the species, need areas for foraging with moist ground cover, with Carex swamps and wet meadows. Triturus cristatus forages on semi-natural grasslands

Many former moist areas, pond edges and semi-natural communities have gone out of use during recent decades – this has caused these areas to overgrow with brushwood, reducing the ability of Emys orbicularis, Bombina bombina and Triturus cristatus to forage there. The loss of open, sun-exposed moist and terrestrial habitat can reduce the availability of foraging areas and the opportunities for migration. If a valuable foraging or migration corridor area disappears or loses its value, a population’s long-term survival is out of the question

The management of moist areas covered with reed and Carex vegetation and semi-natural communities (grazing and mowing) keeps these areas open and provides Emys orbicularis,Bombina bombina and Triturus cristatus with favourable foraging and migration conditions. With well-managed wet swampy and drier grassland, the populations can build up in size and a connection between the existing small isolated populations can be a reality in the future.