Conservation Measures and Future Perspectives for Europe’s Most Threatened Frog: The Action Plan for Karpathos Water Frog (Pelophylax cerigensis)

TL;DR

This paper outlines a conservation plan for the endangered Karpathos water frog, focusing on habitat restoration and public awareness in Greece.

Contribution

The paper introduces a National Action Plan with specific conservation measures for the critically threatened Pelophylax cerigensis.

Findings

Population decline of the Karpathos water frog is linked to climate change and predation by the Levantine freshwater crab.

A dam construction and taxonomic reassessment of a Rhodes population offer hope for the species' conservation.

Artificial ponds and educational programs are proposed to mitigate threats and raise awareness.

Abstract

The Karpathos water frog (Pelophylax cerigensis) was until recently known to occur only on the island of Karpathos, Greece, and is classified as Endangered (EN) by the IUCN. Its survival is seriously threatened by the lack of freshwater habitats in the southern Aegean, a problem that has worsened due to reduced rainfall and higher summer temperatures. Population studies over the last decade show a strong decline in numbers. During the dry summer months, the remaining natural ponds are often shared with the Levantine freshwater crab, which increases frog mortality through predation. Despite these challenges, some positive developments have occurred, including the construction of a dam in southern Karpathos and the recognition of the Rhodes water frog population as the same species. To address the species’ critical status, the Hellenic Herpetological Society developed a National Action Plan. This plan includes creating artificial ponds, conducting hydrological studies, and implementing education and awareness programs to support the frog’s long-term conservation.

Until recently, the Karpathos water frog (Pelophylax cerigensis) was considered endemic to Karpathos Island (Greece) and has recently been reclassified by the IUCN as Endangered (EN), having been previously assessed as Critically Endangered (CR). The species faces severe threats primarily associated with the scarcity of freshwater bodies in the southern Aegean Sea. Over the past decade, demographic assessments have revealed a marked population decline, driven by the intensifying effects of climate change, including reduced rainfall, and increasing summer temperatures. In addition, the few natural ponds that persist during the dry summer months are often shared with the Levantine freshwater crab (Potamon potamios), resulting in increased frog mortality due to predation. Despite these challenges, recent developments provide cautious optimism. These include the construction of a dam in southern Karpathos and the taxonomic reassessment of the water frog population on the neighboring island of Rhodes as conspecific with P. cerigensis. In response to the species’ precarious status, the Hellenic Herpetological Society designed and implemented a National Action Plan aimed at the protection and conservation of the Karpathos water frog. The Action Plan includes a series of targeted mitigation measures, such as the construction of artificial ponds to retain water during the summer, as well as a hydrological study addressing the seasonal drying of the ecologically important Eleimonitria spring. A key component of the Action Plan involves education and outreach initiatives targeting primary school students, local residents, and visitors, highlighting the frog’s ecological importance and conservation needs. Informational brochures will be distributed across the island to raise awareness of the species’ conservation status and the importance of safeguarding its habitat. The implementation of this Action Plan aims to secure the long-term survival of the Karpathos water frog and to strengthen integrated conservation efforts across its extremely limited range.

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