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Individual study: Captive-bred Pieniny appollo Parnassius apollo frankenbergeri releases help restore the population in Pieniny National Park, Prešovský, Slovakia

Published source details

Adamski P. & Witkowski Z.J. (2007) Effectiveness of population recovery projects based on captive breeding. Biological Conservation, 140, 1-7

Summary

The Pieniny apollo, Parnassius apollo frankenbergeri, is endemic to a mountain range straddling the Slovakian-Polish border. In Slovakia it is restricted to Pieniny National Park (where in the late 1980s and early 1990s it was near extinction) and the Haligovske Hory massif. A serious population decline has occurred, attributed to degradation of its alpine grassland habitat due to afforestation and abandonment of traditional grazing. This study assessed the success of a Pieniny apollo recovery programme, initiated in 1991, in the National Park which included habitat management and releases of captive-bred butterflies.

Study area: The 37.5 km² Pieniny National Park (Pieninský národný park) is located in northern Slovakia. In 1991, the total area of prime habitat within the Park for the apollo was about 10 ha divided between a number of fragmented sites. The apollo only occurred at one of these sites, the Trzy Korony massif, with a population of only 20-30 adults; a large and increasing proportion had malformed wings, perhaps linked to inbreeding.

Habitat management:  Surveys indicated that the caterpillar host plant, Sedum maximum, was quite common but that much occurred in afforested (shaded) areas and thus unsuitable to the butterfly. To extend the amount of open grassland, management focussed on tree and shrub removal from localities where the butterfly had previously occurred. By 2003, a series of suitable habitat patches totalling around 19 ha had been created.

Captive-breeding and releases: The captive breeding programme was established in 1991, founding individuals taken from Trzy Korony. This population was supplemented with captive-bred individuals from 1992 to 2001. In 1995, in order to reduce potential genetic problems, the programme incorporated some butterflies from the next nearest apollo population at Haligowskich Skaly on the Polish side of the border.

Population sizes were determined by mark and recapture studies of adults (captive bred individuals were marked prior to release).

During the period of habitat management and releases, the butterflies expanded from Trzy Korony to form over 12 subpopulations occupying most suitable sites within the Park; the population increased to around 1,000. Some subpopulations appeared stable, whilst survival of others seemed dependent either on a supply of captive-reared individuals or on emigrants from other subpopulations to persist. In some cases, despite supplying a subpopulation with captive-reared individuals, abundance decreased.

The authors urge that despite these overall positive results, releasing captive-reared butterflies to bolster an endangered population entails risks and should be done with caution and only after very careful planning.


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