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Population dynamics of feral horses ( E quus caballus ) following above‐average rainfall in a semi‐arid environment of A ustralia
Author(s) -
Kampmann S,
Hampson BA,
Pollitt CC
Publication year - 2013
Publication title -
australian veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.382
H-Index - 59
eISSN - 1751-0813
pISSN - 0005-0423
DOI - 10.1111/avj.12120
Subject(s) - arid , equus , population , fauna , geography , ecology , habitat , population growth , domestication , foal , biology , demography , archaeology , sociology
Background Recent record rainfall in much of semi‐arid Central A ustralia is the most likely reason for a feral horse population increase in excess of normal. Uncontrolled numbers of feral horses have habitat degradation and animal welfare implications. Objectives The aims of this study were to investigate the social structure of feral horses and assess their population growth rate following unseasonably high rainfall. Methods The study area was 4000 km 2 of unmanaged, semi‐arid country in Central A ustralia (latitude 24.50° S , longitude 132.10° E ). Horses were identified by descriptive features from ground searches, movement‐activated cameras and ‘hides’ positioned at key water holes. Wherever possible, sex and age categories were documented. Population growth rate was estimated by the number of foals divided by the number of horses older than 1 year in the observed population. Results A total of 1424 horses were identified and categorised, of which 335 were foals born within the current year. Only 123 juveniles were identified. Of the adult horses, 53.4% were male and 46.6% were female and this differed from parity (P = 0.04). Of the mares, 71.9% had a foal at foot and the population growth rate was 29.5%. Conclusions With a sustained population growth rate of 29.5%, this population of feral horses will more than double within 3 years. The high population increase will likely have a detrimental effect on native fauna and flora and the fragile, semi‐arid ecosystems of Central A ustralia. After a period of high rainfall and plentiful resources, ‘normal’ drought conditions will return and many feral horses will starve and die as they compete for limited resources.