Evaluation of harem stability in wild and feral horses

Lucie Mojžíšková

Bachelor's thesis

Abstract:

Wild and feral horses form relatively stable groups called harems, with strong long-term bonds between the members. Occasionally the stability is disturbed by individual horses changing bands. The thesis aims to provide a comprehensive review of existing literature on harem stability, to evaluate the main factors that have an impact on the rate of the changes and to extract and evaluate numerical data through a meta-analysis. The research shows several mutually interconnected factors, that affect harem stability to different levels. The factors were divided into two categories. First category covered the external factors, which include environmental and seasonal changes, and human intervention in the form of fertility control via immunocontraceptions and surgical sterilizations. Second category covered the individual factors, that arose from the band itself, including behavioural aspects and hierarchical structure of the band. The secondary aim to conduct meta-analysis to analyse rates of harem stability was unsuccessful, as existing numerical data regarding changes in the structure of bands are incomparable. The formula for calculating the rate of stability was different for each study and neither the criteria, on which the calculations were based (age of horses, sex of horses, time period during which changes in harems occurred) were not set up in a unified manner, therefore no statistical analysis could have been drawn from the review. The different methodologies of harem stability calculations included counting individual horses that left the band, ratios of horses that left to horses that stayed with the band, or simple observation, whether the mares are still seen with the same stallion. Some researchers set up more complex formulas with specific time-binding and other criteria, to calculate the rate of harem stability. Further research on harem stability of individual horse populations, as well as unification of the calculations will be necessary to ensure proper management and successful reintroduction projects.

Keywords

Environmental effects, Individual effects, Meta-analysis, Reproduction, Social organization, Social structure

Language used: English

Date on which the thesis was submitted / produced: 20. 4. 2024

Thesis defence

• Date of defence: 27. 5. 2024
• Supervisor: doc. Francisco Ceacero Herrador, Ph.D.
• Reader: Martina Komárková, Ph.D.

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Bachelor programme:
International Cooperation in Agricultural and Rural Development