Epsilon Archive for Student Projects

Abstract

Habitats worldwide have undergone changes which have had effects on the living conditions for many species. Some landscapes have opened up due to agriculture, others have changed into fragmented monocultural habitats due to forestation. This has in some places led to the loss of biodiverse half-open landscapes that used to be more common in Europe during the 18th and 19th century. These half-open landscapes are believed to have been characterized by natural disturbances such as large grazing herbivores and recurring fires. Recreating and maintaining some of the half-open landscapes is crucial in the work of conservation. It is well known that both the effect of grazing herbivores as well as fires can be a natural way to pursue this work. What is less known is the effects these two factors have on each other.
This study was therefore carried out to get a better understanding of how fires affect grazing behaviour of large herbivores, in this case cattle. Two breeds of cattle were studied; the traditional Swedish breed Rödkulla and a commercial breed originating from the UK, Hereford. The study was performed as part of a larger ongoing project in Ekoparken, Nordens Ark, in southwestern Sweden. A total of 14 plots containing one area of previously burned vegetation as well as one area of untouched vegetation each was created in larger pastures. Each plot had a burnt and an unburnt area of 7 x 7 m, i.e. twice 49 m2, and was equipped with cameras to capture the grazing cattle from May to October 2015. The amount of time each animal, visiting one of the 14 plots, spent grazing on the burned area, as well as the unburned, was recorded and later analyzed. The power of the fire varied between the different plots. For 6 plots an area of on average 68,4 % burned whilst only an average area of 4,6 % burned for the other 8 plots. The 6 plots which burned more contained a total of 165 observations and for the other 8 plots the number of observations were 1085.
The cattle in this study spent more time grazing the burnt area compared to the unburnt area but only in the 6 plots with a powerful fire. In the other 8 plots, that were only burnt marginally, there was no difference in grazing behavior between burnt and unburnt. This result agreed with the hypothesis based on the supposedly higher nutritional value of the newly grown grass following a fire. Only the traditional Swedish breed, Rödkulla, spent more time grazing the burned area in comparison to the unburnt area whereas Hereford did not show any preferences. The results showing a preference in grazing on a burned area over an unburned area is important knowledge for understanding the relationship between fire and grazing. This knowledge can be used in managing conservation work more effectively in the future.