Atlas entry registered by Dr. Alberto Scorolli, based on work and research carried out with the feral horses at Ernesto Tornquist Provincial Park (website).
Country: Argentina Region/Province/Range: Ernesto Tornquist Provincial Park (ETPP) – Buenos Aires
Species: Equus caballus Subspecies/Breed/Type: Feral Creole
Estimated Population size: +/- 400 horses (2014)
Management Authority: Ernesto Tornquist Provincial Park (ETPP)
Management Practices: Population Management Strategy is urgently needed
Ernesto Tornquist Provincial Park (ETPP) is located in the south of the Province of Buenos Aires, Argentina, between 38 º 00’- 38º 07’S and 61º 52’- 62º 03’W. This natural reserve was established in 1938 and covers 67 Km2 of hilly grassland with heights ranging between 450 and 1175 m above sea level. The climate is temperate and humid (Burgos 1968) with a mean annual rainfall of 800 mm. Rains fall mainly in spring with a second peak in autumn. Snowfalls are occasional and, in general, light. The typical vegetation is grassland steppe dominated by species of the genera Stipa and Piptochaetium (Cabrera 1976; Frangi and Bottino 1995).
This Natural Protected Area is very important for biodiversity conservation as it includes many endemic plant and animal species (Kristensen and Frangi 1995). In 1942 a small group between 5-10 horses, which became feral, were introduced to ETPP. In 1995, their descendants, 450 horses, occupied a fenced-off sector of approximately 20 Km2 (Scorolli 2007). These horses were of Creole breed, like all other feral horse populations in Argentina. This breed has originated from Spanish and Andalusian horses, of essentially African barb ancestry, brought to South America by the colonizers during the XVI century (Cabrera, 1945).
Structure and demographics
Currently approximately 40 harem-bands, most single stallion H-Bands. Population size in year 2014 400 feral horses, sex ratio 1:1. adult+sub-adult+yearling: foals (7:1).
Issues worth noting and needed actions
Current density 20 horses/km2, in year 2001-2002 population was food-limited, approaching carrying capacity and reaching 35 horses/km2 (annual mortality more than 80 horses/year).
In 2014 after a massive fire in January and a exceptionally rainy year (highest in decades) the body condition is good and the demographic potential to increase is also high!!
A Population Management Strategy is urgently needed in order to reduce current population size to appropriate levels that preclude high mortality by starvation and environmental impact in a natural protected area created by its grassland biodiversity unusual value.
There is a conflict between government authorities and some horse protection groups that see management as unacceptable.
Bibliography and Further reading
Scorolli, A.L., A.C. Lopez Cazorla and L.A. Tejera. 2006. Unusual mass mortality of feral horses during a violent rainstorm in Parque Provincial Tornquist, Argentina. Mastozoología Neotropical 13: 255-258.
Scorolli, A.L. 2009. Feral horse management in Argentina. In 10th. International Mammalogical Congress. Mendoza, Argentina.
Scorolli A.L. y López Cazorla. 2010a. Demography of feral horses (Equus caballus): a long-term study in Tornquist Park, Argentina. Wildlife Research 37: 207-214.
Scorolli, A. and A. Lopez Cazorla. 2010b. Feral horse social stability in Tornquist Park, Argentina. Mastozoología Neotropical 17 (2): 391-396.
Scorolli, A.L. 2012. Feral horse demography and management in Tornquist Park, Argentina. International Wild Equid Conference. VetMedUni, Viena.
Scorolli, A.L. 2012. Feral horse body condition: a useful tool for population management?. International Wild Equid Conference. VetMedUni, Viena.
About potential environmental impact
de Villalobos, A.E. and S.M. Zalba. 2010. Continuous feral horses grazing and grazing exclusion in mountain pampean grasslands in Argentina. Acta Oecologica 36: 514-519.
de Villalobos, A.E., S.M. Zalba and D.V. Peláez. 2011. Pinus halepensis invasion in mountain pampean grassland: Effects of feral horses grazing on seedling establishment. Environmental Research 111: 953-959.
Loydi, A. and S.M. Zalba. 2009. Feral horses dung piles as invasion windows in natural grasslands. Plant Ecology 201: 471-480.
Loidy, A. and R.A. Distel. 2010. Diversidad florística bajo diferentes intensidades de pastoreo por grandes herbívoros en pastizales serranos del Sistema de Ventania, Buenos Aires. Ecología Austral 20: 281-291.
Loidy, A., R.A. Distel and S.M. Zalba. 2010. Large herbivore grazing and non-native plant invasions in montane grasslands of central Argentina. Natural Areas Journal, 30(2): 148-155.
Zalba S.M. and N. Cozzani. 2004. The impact of feral horses on grassland bird communities in Argentina. Animal Conservation 7: 35-44.