Miloslav Homolka

Suitability of NIRS analysis for estimating diet quality of free-living red deer Cervus elaphus and roe deer Capreolus capreolus

In this study, we tested the efficiency of near infrared reflectance spectroscopy (NIRS) to assess nitrogen content in faeces of free-living ruminants. Faecal nitrogen (FN) content was analysed in 168 pellet groups from red deer Cervus elaphus and roe deer Capreolus capreolus in the growing season and in winter using both the standard Kjeldahl method and NIRS analysis. Estimates of nitrogen content obtained by the two methods did not differ (P > 0.1), and the correlation between FN values was significant (P < 0.001). FN content ranged within 1.10–4.58% of dry matter and, as anticipated, it was higher in the growing season than in winter in both species (P < 0.01). Faecal nitrogen values were also higher for roe deer than for red deer, although the difference was only significant in the growing season (P = 0.007). Our study confirmed that faecal nitrogen of free-living ruminants can be accurately determined with NIRS analysis. NIRS represents a low-cost analytical technique, which could replace conventional labourious methods and is highly promising for analyses of diet quality in free-living ruminants.

An assessment of the applicability of photo trapping to estimate wild boar population density in a forest environment

Abstract. Wild boar is an autochthonous animal species of the Czech Republic that has significantly increased its population density in recent years. There are concerns that there is an associated negative impact upon agricultural crop production however, objective methods for sustainable management of wild boar, especially for estimation of its population density and intensity of regulation are still lacking. Wild boar differs markedly from the other free-living ungulates in its spatial activity and food selection, which limits applicability of the experiences and methods used for other species. Two methods of wild boar population censusing in a forest environment were tested in this study. The density of wild boar was evaluated in an area of 2256 ha, circumscribed by both natural and man-made barriers that restrict wild boar migration. Wild boar abundance was estimated using traditional snow-track counting and photo trapping data analysis. Both field methods were used in the winter season 2009-2010. Wild boar abundance as assessed by snow-track counting was 6.3 ind./km2 and by phototrapping 6.8 ind./km2. The results have revealed that if correctly performed, both of the tested methods are applicable to estimate wild boar abundance. Photo trapping seems to be more accurate; it requires special equipment and is time-consuming, however, it provides additional information on the structure of the population and requires less experience to undertake. Combination of several methods is advisable.

Rodent Damage to Natural and Replanted Mountain Forest Regeneration

Impact of small rodents on mountain forest regeneration was studied in National Nature Reserve in the Beskydy Mountains (Czech Republic). A considerable amount of bark damage was found on young trees (20%) in spring after the peak abundance of field voles (Microtus agrestis) in combination with long winter with heavy snowfall. In contrast, little damage to young trees was noted under high densities of bank voles (Myodes glareolus) with a lower snow cover the following winter. The bark of deciduous trees was more attractive to voles (22% damaged) than conifers (8%). Young trees growing in open and grassy localities suffered more damage from voles than those under canopy of forest stands (χ 2 = 44.04, P < 0.001). Natural regeneration in Nature Reserve was less damaged compared to planted trees (χ 2 = 55.89, P < 0.001). The main factors influencing the impact of rodent species on tree regeneration were open, grassy habitat conditions, higher abundance of vole species, tree species preferences- and snow-cover condition. Under these conditions, the impact of rodents on forest regeneration can be predicted. Foresters should prefer natural regeneration to the artificial plantings.

Needles in faeces: an index of quality of wild ungulate winter diet

Abstract. Norway spruce is a wide-spread food resource and its utilisable biomass exceeds the needs of herbivores. Needles seem to be a generally ignored food component in temperate forests that is consumed only when there are no better food sources. It is used especially during winters with deep snow cover. The aim of this study was to test presumption of needles as nutritive poor component of ungulate diets through botanical diet analyses and chemical nutrition estimation (content of crude protein and metabolizable energy volume in faeces) and elaborate the calibration curve on indirect estimation of quality food resources for ungulates in environment (NIRS needle content in faeces). High content of spruce needles corresponded well with a low quality winter diet of wild ungulates and may reflect animal nutritional constraints. As a consequence, the content of spruce needles may be used as an easy index of animal performance in a particular environment in forested area with coniferous forests in temperate zone. Needle content can be determined from the faeces by near infrared spectrophotometer and this easy technique can be recommended as indicator of the food resources quality for ungulates.