Ocena potencjalnej bazy żerowej jelenia szlachetnego (Cervus elaphus L.) w Puszczy Rominckiej

Siuta Alicja

Abstract

The studies were conducted in the Polish part of the Romincka Forest (ca 13.1 thousand hectares) located in the Northeast of the country in the Warmia-Masuria region, Goldap Forest District, in the years 2000/2001 to 2002/2003. The objective of the research was to assess the potential feed base for Red Deer (Cervus elaphus L.) and the nutritive value of fodder plants. The research involved the following: determination of the deer population density; measurement of the amount of the biomass of shoot fodder and forest floor vegetation in three types of forest site such as fresh forest, fresh mixed deciduous forest and fresh mixed coniferous forest; determination of the levels of basic nutrients, gross energy and some mineral components in the plants constituting the biomass of deer fodder; analysis of deer's food preferences with regard to individual plant species; characterisation of the winter diet of deer; assessment of the damage caused by deer to the plantation forests in the study area; and calculation of the energy balance in a barren hind of 120 kg body mass. An equation of linear regression was worked out to calculate the size of the Red Deer (Cervus elaphus L.) population in the Romincka Forest. The equation took into account the relation between the population size and the track density index of the deer. The calculation yielded the number of 185 individuals in the study area, which corresponds to the density of 15.4 animals per 1000 ha. The use of a quite novel technique for estimating the deer population size by means of mathematical models considering the number of tracks counted on transects allows a relatively precise and objective estimation of deer density while substantially reducing the time and labour needed for measurements. Since the traditional methods of measuring the population size of wild animals in their habitat do not ensure sufficient accuracy and usually bear considerable error due to subjectivity, they call for revision. Therefore, if the technique mentioned above proves to ensure a greater consistency and repeatability of the results, it may be officially accepted as a standard method to be commonly used in the hunting practice. A twig count method was employed to determine the supply of shoot fodder (browse), and a harvest technique was used to estimate the biomass of forest floor vegetation. Based on the results, the potential winter feed base for Red Deer (Cervus elaphus L.) in the whole area under study consists of 2349 t d.m. of fodder. The dominant type of winter browse in the plantation forests is the twigs of deciduous tree species such as Quercus sp., Car pinus sp. or/and Betula sp., while in timber stands, the twigs of Rub us sp. and of Betula sp. and Picea sp. The reserves of the winter browse biomass are closely connected with the forest site type, being the largest for the fresh mixed coniferous forest with dominating conifers, mainly Picea sp. The resources of forest floor vegetation markedly vary with site. This category of plant fodder accounts for a major proportion of the potential deer feed. The calculated biomass resources, amounting to 59.3 t d.m., considerably exceed the actual consumption of feed by the deer population (185 individuals) inhabiting the Romincka Forest. Over the whole winter season, assumed to last 120 days in this region, the deer take in 47.1 t d.m. of feed on average. An analysis of the rumen content together with the count of browsed and unbrowsed twigs made it possible to determine the diet selection by deer and the damage to forest by their population. In the winter season the deer diet consists mostly of grasses and sedges which provide the animals with the indispensable energy and nutrients (protein and other). On the other hand, the preferred species of browse plants probably make the main source of micro- and macroelements that are essential for the normal course of metabolic processes in the organism. The research determined also the levels of protein, fat, total fibre, neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) fractions and some mineral components (Ca, P, Mg, Na and K) in the plants in question, as well as the gross energy content of the plants. The nutritive value of shoot fodder and forest floor vegetation, constituting deer feed, displayed seasonal variation. The plant material of the winter season had higher levels of total fibre and its fractions, but a significantly lower protein content than that of the summer season. As indicated by the gross energy content, the plants had a higher calorific value in the winter season. The twigs of deciduous tree species preferred by Red Deer (Cervus elaphus L.) as a source of browse presumably constitute the critical element of their feed base. Therefore, the biomass of these species, excluding the species significant to silviculture such as Quercus sp. or Fraxinus sp., should be an important determinant of the admissible deer density. The total amount of the browse biomass in the whole study area of the Romincka Forest was found to be 16.1 t d.m. Assuming a 10% proportion of these species in the deer diet, the present population would consume in the winter season only 4.71 t d.m. (29.2%) of such food. If the consumption limit is set at 50% of the reserves, the potential size of the deer population in the Romincka Forest ecosystems might increase to 280.4 individuals, corresponding with the density of 23.3 animals per 1000 ha. The deer food-carrying capacity of the Romincka Forest should be defined on the basis of the biomass of herbs and undershrubs, mostly Vacciniurn sp., because they form the main and efficient source of energy for the animal species in question. The reserves of the biomass of this feed in the Romincka Forest at the beginning of winter amount to 43.2 t d.m. Taking into account that the damage caused by the deer to the plantation forests can be considered economically tolerable as it does not exceed 20% of the study area, it is suggested that the game management should aim to increase the size of its population to ca 300 animals by systematically cutting within two or tree hunting seasons the number of animals being shot. However, rationalisation of the management of the hunting ground will also require increasing the number of winter feed plots supplied with multicomponent fodder mixtures. Such mixtures would greatly enhance the existing relatively poor natural feed base for deer in the hard-to-survive winter seasons.
Other language title versionsAssessment of the potential feed base for Red Deer (Cervus elaphus L.) in the Romincka Forest
Book typeMonograph
Other categories ROZPRAWA_HABILITACYJNA
Author Siuta Alicja (FoAS)
Siuta Alicja,,
- Faculty of Animal Sciences
PublisherUniwersytet Rolniczy im. Hugona Kołłątaja w Krakowie, MNiSW [80]
Publishing place (Publisher address)Kraków
Issue year2006
Book series /Journal (in case of Journal special issue)Zeszyty Naukowe Uniwersytetu Rolniczego im. Hugona Kołłątaja w Krakowie. Rozprawy, ISSN 1899-3486, (0 pkt)
Vol429
No313
Pages129
Publication size in sheets9
Languagepl polski
Score (nominal)20
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