Thijs Kramer and B.R. Vickers, PROTECFAUNA S.A., Son Cifre de Baix, Manacor, Mallorca (Spain)
Present address: Rembrandtlaan 40, 1213 BH Hilversum, The Netherlands.
(2nd European Chelonian Symposium)
Testudo hermanni robertmertensi WERMUTH occurs in the S'Avall valley of NE Mallorca. As a conservation measure, Son Cifre de Baix, a barranco in the S'Avall valley including the tortoise and its habitat, has been dedicated as a nature reserve.
Testudo hermanni robertmertensi WERMUTH 1958 occurs on Mallorca (Balearic ls.) within its European, western Mediterranean range of distribution (MERTENS & WERMUTH, 1960. LOPEZ JURADO et al., 1979; CHEYLAN, 1981 ). Threats to the sub-species's survival and its habitat are described in this work.
Since 28 September 1978, a nature reserve, at present of 20 ha, has been established on Mallorca at Son Cifre de Baix, near Manacor, and has been provisionally described by BLOKHUIS (1979), VROOM ( 1979). The reserve is part of the S'Avall valley and is a quite inaccessible barranco containing scarcely disturbed habitat with T h. robertmertensi amongst other species of reptile. bird and mammal. The reserve has now been transferred to the charge of an international Patronate to ensure it survives as a valuable refuge and has the support as a conservation project of the IUCN Species Survival Commission Tortoise Group.
Mallorcan T. H. robertmertensi compared
There appear to be three forms of Testudo hermanni GMELIN 1789 in the Mediterranean region: eastern ( T.h. hermanni), central and western (T. h robertmertensi). T. h. robertmertensi at Son Cifre de Baix is the western form and similar to the type specimen from Arta, Mallorca, occurring only on the Balearic Is. and the mainland of Spain and France. On Corsica, Sardinia and Elba. the form differs in the pattern of pigmentation and size; the bright yellow of the western T. h. robertmertensi becomes a duller , rather poorly defined orange- Moreover, there is a transition west to east from an oval outline to a trapezoid shaped carapace. T h. robertmertensi on the Balearic Is. has black claws on the hind limbs and yellow and black front claws (rarely the hind claws are black and yellow. the front claws are then totally yellow), while in Italy from Naples eastwards, the claws of T. h. hermanni are of a uniform pale colour. The size increases from west to east and on Mallorca, the carapace of the largest female known is 16. 5 cm and male 14.0 cm; in Provence (France), 18.5cm and 16.6cm, respectively (CHEYLAN, 1981 ), and on Corsica, 24.5 cm and 18.0 cm. respectively. T. h. robertmertensi on Mallorca is the smallest form, although to speak of it as a dwarf form is probably an exaggeration. T. h. robertmertensi is physiologically weaker than T. h. hermanni and apparently sur-vives less well in captivity than central or the eastern Mediterranean forms.
Main population of Mallorca
The main remaining populations of T h. robertmertensi on Mallorca are to be found in the S'Avall valley and adjoining coastal strip which have not suffered from fires in recent years. The mouth of the valley opens on to the north-east coast and forms a marshland. The valley itself is about 3 km wide with the Na Borges stream running down its length. It is a prime area on the Balearic Is. for forming into a nature reserve, containing the vegetation characteristic of the tortoises. habitat.
The habitat for T. h. robertmertensi varies in different areas only in vegetational density and age of development. The plant communities range from Oleoceratonetum to Rosmarino.ericetum, which are never in a pure or complete stand and interspersed with other plant species.
The Oleo-ceratonetum comprises the following species:
- Olea europaea Ceratonia siliqua
- Clematis cirrhosa Asparagus albus
- Asparagus stipularis Cneorum tricoccon
- Chamaerops humilis Euphorbia dendroides
- Ephedra fragilis Arum pictum
The Rosmarino-ericetum comprises the following species:-
- Erica multiflora Anthyllis cytisoides
- Globularia a lypum Laoandula dentata
- Rosmarinus officinalis Genista lucida
- Teucrium polium Gladiolus illyricus Orchidaceae spp.
Other plant species interspersed with Oleo-ceratonetum and Rosmarino-ericetum are of the following:-
- Asparagus acutifolius Pinus halepensis
- Plantago spp. Ampelodesma mauritanica
- Brachypodium ramosum Cynodon dactylodon
- Hyparrhenia hirta Oryzopsis miliaceae
- Asphodelus microcarpus Smilax aspers
- Cistus monspeliensis Cistus albidus
- Rubia peregrina Carlina corymbosa
- Cynara cardunculus Bellis syloestris
- Pallenis spinosa Rubus ulmifolius
- Phyllirea spp. Pistacia lentiscus
- Prunus spinosa Foeniculum oulgare
- Rhamnus alatemus Quercus ilex
Certain other plant species occur in special circumstances such as when the vegetation is regenerating after fire. Such species are Merendera filifolia and Daphne gnidium, which contain a range of strong alkaloids. It would be interesting to investigate their effect on, for example, breeding.
T. h. robertmertensi carries out a pattern of migration during the period of activity. In the S' AvaIl valley, the tortoises are to be found on high ground during the wet winter season for otherwise they could drown at lower levels which become flooded. During the hot, dry summer, they move lower down where more green vegetation remains providing food in late summer.
Threats to survival
Fires. Fires are a particular hazard to T. h. robertmertensi throughout most of its western Mediterranean range. On Mallorca, the tortoises' range has been reduced by fire year by year and while trying to establish their distribution, one comes across hills completely stripped of vegetation by fire. Only infrequently does one come across corpses and the mortality rate apparently varies with vegetation structure and level of burning. During the 1981 Summer alone, 300 ha of tortoise habitat in the eastern part of the island were destroyed by fires, all started intentionally. The yearly toll of tortoise habitat through burning is about 5OO ha.
On account of exceptionally heavy touristic requirements, many of the coastal areas have been turned over to building development.
Tortoises are collected from the wild and 300.400 are shipped out of Mallorca yearly, mainly for a domestic market on the mainland. Some tortoises are sold locally in pet shops, but this has become less frequent; in September 1981 , a pet shop in the capital of Palma was selling Testudo graeca graeca shipped from the mainland of southern Spain. Tortoises are also sold as stuffed souvenirs, the last record of which was in the fleamarket of Palma in November 1980.
Sheep and goat grazing in tortoise habitats does not appear to have any serious influence on populations, although serious problems could arise if grazing is very intense. Fortunately, sheep and goat grazing are not widespread on Mallorca
Rabbits are also present in the habitats frequented by tortoises, but do not appear to pose a serious threat so long as their numbers are kept in control. Hunters control the rabbit numbers very effectively in unprotected areas, but where hunters are excluded rabbit control measures are required. T. h.robertmertensi often use rabbit burrows as refuges and for egg laying, but occasionally tortoise nests are unearthed by the unceaseless digging of the rabbits. Rabbits can also be competitive grazers to tortoises in their habitats and may cause soil erosion by their digging. Feral pigs are low in numbers and very localised and therefore pose no real threat.
A conservation measure
A proposal is being prepared to designate the whole of the S' AvaIl valley as a nature reserve. The mouth of the valley is marshland, attracting dry and wetland birds equally during their migration. Seven species of amphibians and reptiles, many bird species, including the peregrine falcon (Falco peregrinus), and a large number of endemic and rare species of invertebrates and plants have also been recorded in the valley. As a start, the Son Cifre de Baix has been dedicated as a reserve. Through the guidance of a board of trustees of local and international representatives, it is hoped it will provide a model and give rise to expansion when developed and refined as a reserve.
BLOKHUIS, w A. ( 1979): Physiography, geology and soils of Son Cifre de Baix (Mallorca, Espana) (preliminary report). Unpublished. Mimeograph, 9 pp.
CHEYLAN, M. ( 1981 ): Biologie et ecologie de la tortue d'Hermann Testudo hermanni
GMELlN, 1789. Contribution de I'espece al la connaissance des climats quaternaires de la France, Mem. Trav. E.P H.E. lnst. MontpeIlier No. 13: 1 -404.
LOPEZ JURADO, L.F . , TAVERA TORRALBA, P.A., IBANEZ GONZALEZ, J.M. MACIVOR, JA., GARCIA ALCAZAR, A. (1979): Las tortugas terrestres Testudo graeca y Testudo hermanni en Espana. NaturaIia Hispanica No. 17. Madrid, l.C.O.N.A
MERTENST R.. WERMUTH, H. ( 1960): Die Amphibien und Reptilien Europas (Dritte Liste, - . -). Frankfurt/ M" W. Kramer.
VROOM, T. (1979): Herfstreis naar Mallorca- De schildpad 5(6): ] - ] 2.
A provisional list of reptiles, birds and mammals recorded at Son Cifre de Baix, Manacor (A. LLUL BIBlLONl, unpublished).
Hermann's tortoise ( Testudo hermanni robertmertensi)
Mediterranean spur-thighed tortoise (Testudo graeca graeca) - extinct; remains found
Moorish gecko ( Tarentolca mauritanica )
Turkish gecko (Hemidactylus turcicus)
False smooth snake (Macroprotodon cucullatus)
Viperine snake (Natrix maura)
Barn own ( Tyto alba)
Long-eared owl (Asio otus)
Short-eared owl (Asio flammeus)
Scops owl (Otus scops)
Spanish raven (Corvus corax)
Red kite (Milvus milvus)
Booted eagle (Hieraetus pennatus)
Kestrel (Falco tinnunculus)
Merlin (Falco columbarius) - overwintered
Peregrine falcon (Falco peregrinus)
Sparrowhawk (Accipiter nisus) - overwintered
Buzzard (Buteo buteo) - overwintered
Brown hare (Lepus capensis granatensis) - probably extinct, remains found
Rabbit (Oryctolagus cuniculus)
Pine marten (Martes martes)
Genet (Genetta genetta)
Weasel (Mustela nivalis)
Ferret (Mustela putorius furo)
Vagrant hedgehog (Aethechinus algirus)
White toothed shrew (Crocidura balearica )
Woodmouse (Apodemus sylvvaticus)
House mouse (Mus musculus )
Testudo Volume 2 Number 2 1983