Vjetrenica Cave, Ravno

Brief synthesis

Vjetrenica Cave, Ravno is recognised as one of the world’s most important and species-rich biodiversity hotspots for subterranean fauna in the world. The property contains globally important levels of subterranean species diversity, endemicity, single-genus diversity and species considered as living fossils. Located in the South Dinaric Karst range in southern Bosnia and Herzegovina, Vjetrenica Cave, measures 7,324 meters in length and forms part of the Trebišnjica river system. The Cave provides one of the most well documented examples of the cave hygropetric habitat, an intermediate between aquatic and terrestrial ecosystems denoted by a thin layer of water moving over vertical rock surfaces.

Criterion (x): The property stands out on a global level for its exceptional cave biodiversity and endemicity and can be considered one of the most important hotspots of subterranean faunal diversity globally. More than 230 taxa have been recorded in the Vjetrenica Cave System, including 180 animals, 14 fungi and 35 protists. Altogether, 93 troglobiotic, i.e., obligate subterranean aquatic (48) and terrestrial (45), taxa have been reported for the system, of which 40 were first scientifically described from the property (the property represents the type locality). Vjetrenica Cave also stands out as an exceptional example of single-genus diversity – the nine species of the subterranean amphipod genus Niphargus, which may represent the highest subterranean single-genus diversity in the world.

The exceptional endemicity of the property is illustrated by its stygofauna, of which 78% are only found in the Dinaric region. Vjetrenica Cave is habitat for the only subterranean tubeworm in the world (Marifugia cavatica) and the only freshwater hydrozoan living exclusively in groundwater (Velkovrhia enigmatica). In addition, several of the species found in Vjetrenica Cave are Tertiary and pre-Tertiary relict species, considered as living fossils, whose closest living relatives went extinct a long time ago. The property is also reported to host 21 plant species that are endemic to the Balkans.

Integrity

The area of Vjetrenica Cave (22.87 ha) is embedded within the larger property (413.97 ha). Despite its small size, it is home to the significant subterranean fauna and main cave features and habitats, for which the property is inscribed. The boundary design of the buffer zone appears to cover a significant portion of the catchment, and adequately provides a buffering function to the above attributes of Outstanding Universal Value.

The state of conservation of the cave-dwelling fauna is secure, although given the restricted area of the property, populations are inevitably fragile and prone to impacts from upstream activities, particularly changes to the hydrological regime in the wider catchment of the property. Pressures from tourism, development projects, waste management and their associated pollution are low, although a high level of vigilance and careful watershed management should be maintained in relation to these potential threats.

It is recognised that due to the ongoing research and exploration of the property, and presence of further significant values in the wider Dinaric karst landscape, an extension of the boundaries, or a potential serial transnational extension, may possibly be envisaged in future.

Protection and management requirements

The property is protected through a multi-layer governance framework, under the jurisdiction of various government ministries at the federal, cantonal and municipal level. The entirety of the property and its buffer zone is part of the Vjetrenica-Popovo Polje Protected Landscape, the property being located within the Strict Protection Zone.

Application of the finalised zonation of the Vjetrenica-Popovo Polje Protected Landscape is a priority, and is important for ensuring that the upstream hydrological regime maintains a suitable water supply, inflow, and quality to protect the Outstanding Universal Value of Vjetrenica Cave in the long term.

Management of the property is delegated to the Vjetrenica Public Company Ltd. under the oversight of the Municipality of Ravno and the Herzegovina Neretva Canton. The management body has a management plan, harmonized with the designation law of the protected landscape, and limited staff to manage the property (including tourism).

Key management requirements centre on the protection of the attributes of the unique biodiversity, karst geological features and the wider watershed of Vjetrenica Cave. To ensure the species’ populations and diversity present at the time of inscription is maintained in the long term, it is essential that sufficient and sustainable resources, including staffing and technical capacity, are available for the management of the property. It is important that the management regime of the property focusses not only on tourism management, important in itself as a potential threat, but also enhanced management for nature conservation, including a system of effective biodiversity monitoring within the property, and hydrological management in the wider catchment.