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Kosmos
|
2009
|
tom 58
|
nr 3-4
377-384
EN
Data on sex structure and growth of the population is crucial for proper game management. Camera traps, which are of reasonably low cost, but very efficient, can potentially measure the aforementioned parameters. The paper objectives was to assess the share of bucks, does and calves in red deer Cervus elaphus population in the area of the Białowieża Forest. Two methods were used: camera traps and a traditional method of all−year−round observations. The study was conducted in the years 2011−2015 in three forest districts and the Białowieża National Park. Reconyx trail cameras were exposed in one location for approximately 30 days, then moved to a new place. Altogether, trail cameras were exposed in 761 spots, at least 500 m apart one from another. Analyses were based on material collected between June 1st to September 31st when sex and age identification were the most reliable and hunting season had yet not started. Additionally, all−year−round observations of animals were done by foresters and scientists in the whole forest area, species, sex and age were noted in the special forms. The number of observers was similar to that of exposed trail cameras. Sex and age structure of red deer population changed between years, but according to both methods does were more numerous than bucks. According to trail cameras, share of bucks was on average 42 vs. 32% (data for all years combined), and a population growth was 39−60 calves/100 does, depending on a year. According to all−year−round observation, share of bucks was 26%, of does 53% and there were 37 calves/100 does. The dominance of does over bucks is difficult to explain as the sex structure at birth is 1:1. The does are more susceptible to predation and are culled more often. As data from trail cameras showed lower disproportion, we may assume that those results were more reliable. Trail cameras can collect data all the time, regardless the season, time of a day and weather conditions. Pictures can be analysed in details and observations verified if necessary. Their biggest disadvantage is price (especially when we assume that all−year−round observations can be done as a part of work duties by forest service), and risk of theft or damage.
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