The Adriatic Marbled bush-cricket is listed as Endangered on the IUCN Red List of Threatened species. It is only found in a few wetland areas at the Adriatic coast of Italy and in the Slovenian marshes south of Ljubljana. The species is found in sedge and reed marshes and depends on a high water level. The habitats of this species have been destroyed due to drainage for agricultural land use and urbanization/industrialization. It was already thought to be extinct, until a large population was rediscovered near Monfalcone (Italy) in 1996. This population has decreased significantly as the habitat has been converted to industrial areas and drained. In Slovenia, the species was discovered in 2004 in Ljubljansko barje, the marshes near Ljubljana between Ig and Skofjliika. In 2008 the size of the Slovenian subpopulations was estimated at about 1,000 males (i.e. a population size of 2,000) on an area of about 1 km² (Veenvliet 2008). This area has recently been heavily transformed into cornfields, so that the Slovenian populations decreased considerably in size.
The major aims of our project were (1) to obtain a recent population size estimate for the Adriatic Marbled Bush-cricket in the Ljubljana marshes and infer the population trend compared to older data, (2) to obtain spatially explicit data on the occurrence of this species in order to identify priority areas for conservation, (3) to reconfirm the existence of this species in the three known localities in Italy, (4) to conduct a workshop together with the local stakeholders in order to derive a conservation strategy for this species.
In 2016, we conducted a first field study on the distribution and abundance in Slovenia. This study showed that the species has become rarer in areas that have been converted to corn fields and that the species is also sensitive to the use of heavy machinery for mowing the sedge meadows. The strategic planning workshops in Slovenia and Italy resulted in two national conservation action plans, which were supported by the regional authorities. First management actions have been implemented, such as fencing off an area that was affected by grazing in one of the Italian populations or mowing a former sedge meadow that was abandoned and affected by scrub encroachment.
Habitat analyses in Slovenia showed that the species prefers sedge vegetation, where males are usually found singing on the top of the sedges. Females are difficult to find and probably hiding in the dense vegetation. As the males of the species appear to sing continuously during good weather condictions, bioacoustic methods are ideal to monitor the population trend. The species appears to be very sedentary and only moves a few meter. It doesn't even cross roads or ditches.
Full implementation of the conservation strategies will require funding of staff for the local reserves in order to secure the best management of the sedge meadows to benefit this species as well as other rare species that are affiliated with its threatened habitat. Our project has helped to raise awareness for this species among local stakeholders, including reserve managers and regional authorities. The publication of two national action plans and their implementation will help to preserve this species from extinction.
Project 162512530 location - Slovenia, Europe