Foraging activity of red deer population on restored mid-forest meadows Daszkiewicz J. and Goliński P. Poznan University of Life Sciences, Department of Grassland and Natural Landscape Sciences, Dojazd 11, 60-632 Poznan, Poland;
[email protected]
Abstract Availability of meadow habitats in the territory of free-living red deer (Cervus elaphus) may reduce the negative impact of these animals on forests and arable crops. The aim of this study was to evaluate the foraging activity of red deer on restored mid-forest meadows. In 2014-2015 two experiments located in North-West Poland were carried out, that investigated the effects of different restoration methods (full tillage, including sowing of three types of seed mixtures: M1 – ‘Blühende Wildäsung’, M2 – ‘Weidgreen Hochwildweide’, M3 – the author’s seed mixture, and overdrilling) vs control surface without restoration on the foraging activity of red deer, based on sward browsing intensity, sward yield and quality. Most of the grazing activity and the highest yield and herbage quality were found within areas restored by the full tillage method combined with sowing of specialised seed mixtures. The results indicate that the areas restored by full tillage and sowing of specialised seed mixtures stimulated grazing by red deer and increased herbage yield and quality. Keywords: mid-forest meadows, red deer, restoration, yield, herbage quality, sward browsing intensity
Introduction Red deer (Cervus elaphus) are considered a keystone species for the functioning of agro-forestry systems and have a great impact on the structure of the ecosystem. The increasing size of the red deer population causes more and more damage to agricultural and forest crops (Marchiori et al., 2012). A limitation of this problem has become an important task for game species management. One possible solution could be to relocate the red deer foraging activity from cultivated areas. Mid-forest meadows (grassland areas surrounded by forest which are grazed by wild animals and/or mown 1-2 times per year for conservation of hay or silage) are habitats that can become attractive feeding grounds for red deer. However, because of their forest proximity and ecotone character, mid-forest meadows are often of low economic and environmental value (Sankey, 2012). Red deer, as all ruminant herbivores, choose feeding patches based on the quantity and quality of available forage (Gerhardt et al., 1993). Therefore, increasing productivity of mid-forest meadows by combining various sward treatments and sowing of properly composed seed mixtures may possibly control their food base. The aim of this study was to evaluate red deer foraging activity on restored mid-forest meadows, based on sward browsing intensity in relation to herbage yield and quality.
Materials and methods The data collection on the foraging activity of a free-living red deer population on restored mid-forest meadows was carried out in 2014 and 2015. For this purpose, two mid-forest meadows in the Polanów Forest District (54°10’ N, 16°78’ E) were used as experimental sites. The control areas without restoration (C) on each meadow were compared to the differently restored areas: (1) full tillage combined with sowing of three types of seed mixtures: M1 – ‘Blühende Wildäsung’; M2 – ‘Weidgreen Hochwildweide’ (both commercially available); and the author’s seed mixture – M3 (composed of 23 species: 7 grasses, 5 legumes and 11 herbs); (2) overdrilling using perennial ryegrass and white clover (O).
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Sward browsing intensity in all experimental areas (0.3 ha each) was assessed by ranking the percentage of grazed area (0 – no foraging evidence; 1 – 0-25%; 2 – 25-50%; 3 – 50-75%; 4 – 75-100% of grazed surface) in 9 separate plots (2×2 m squares). Sward yield was estimated by placing three caged grazing exclosures made of 2×2 m wire mesh within each experimental area. Dry matter (DM) yield was measured based on manually harvested sward samples collected inside the cages. Results are given as an average yield of four harvesting terms, according to the standard management schedule of mid-forest meadows in the Polanów Forest District (sward harvest for hay production in June and October before the end of the vegetation season). The collected herbage was dried in an oven at 60 °C for 48 hours. Chemical composition of the herbage in each of the experimental areas was determined according to the Weende method. Crude ash (CA), crude protein (CP), ether extracts (EE) and crude fibre (CF) were analysed by means of near infrared reflectance spectroscopy; and nitrogen free extractives (NFE) were calculated as g per kg of dry matter. The significance of differences between restoration methods was estimated by the Kruskal-Wallis test (one-way ANOVA on ranks) using Agricolae library for R (version 3.2.3).
Results and discussion The highest average DM yield per cut was observed in the area restored using the full tillage method and seed mixture M1 (3,774 kg ha-1) or M2 (2,496 kg ha-1) (Figure 1). Lower DM yield was observed on M3 sown areas (2,011 kg ha-1). The yields per cut within the overdrilled and control areas were not statistically different (1,692 kg ha-1 and 1,647 kg ha-1, respectively). The sward browsing intensity analysis indicated that the areas restored using full tillage became so attractive to the red deer that they focused about 90% of their foraging activity on these areas (Figure 2). The most preferred was mixture M1 – 46.5% of this treatment area was grazed. The areas sown with mixtures M2 and M3 were less attractive – 31.5 and 31.3% of grazed surface, respectively. Overdrilling did not have a statistically significant effect – only 4.1% of the area was browsed, compared to 3.4% in the control areas. The restoration of mid-forest meadows exerted a significant impact on herbage quality, particularly on CP, EE and CF. The best nutritional quality was recorded in the samples taken from the areas restored by the full tillage method (Table 1): CP content ranged from 171 to 191 g kg-1 DM depending on the seed mixture M1-M3, and was significantly higher than in the samples from the overdrilled and control areas (151.6 and 150.4 g kg-1, respectively). The effect of the restoration of mid-forest meadows on the content of CA and NFE in sward was not observed.
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Figure 1. Effect of mid-forest meadow restoration on dry matter yield.
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Figure 2. Effect of mid-forest meadow restoration on sward browsing intensity. Table 1. Effect of mid-forest meadow restoration on the chemical composition of herbage (means 2014-2015 in g kg-1 of dry matter).1 Restoration method Full tillage + M1 Full tillage + M2 Full tillage + M3 Overdrilling Without restoration P-value
Crude ash 58.0a 65.6a 60.8a 54.8a 54.1a 0.7239
Crude protein 190.7a 172.3a 170.5a 151.6b 150.4b 0.0041
Ether extracts 32.7a 32.8a 31.1ab 28.6bc 28.1c 0.0108
Crude fibre 232.0ab 223.9b 221.6b 255.6a 257.9a 0.0118
Nitrogen free extractives 486.6a 505.4a 516.0a 509.4a 509.5a 0.8948
1 Values marked with the same letter are not significantly different.
The results of our study confirm the statement by Langvatn and Hanley (1993) that, while feeding, red deer select ‘most of the best and least of the worst but some of everything’. The foraging activity of red deer was observed in all experimental treatments, but it was significantly lower in the areas with low sward yield and low quality of mid-forest meadows. Langvatn and Hanley (1993) suggest that protein content in the herbage is a better indicator of forage attractiveness for red deer than productivity. In our study, the highest quality of herbage (as indicated by a high CP) was observed within areas restored using the full tillage method, and correlated with the highest sward yield.
Conclusions The restoration of mid-forest meadows using full tillage combined with sowing of specialised seed mixtures positively affected both herbage yield and quality, which leads to greater foraging activity of free-living red deer. The sward browsing intensity of animals was significantly lower within the overdrilled and the control areas.
References Gerhardt P., Arnold J.M., Hackländer K. and Hochbichler E. (2013) Determinates of deer impact in European forests – A systematic literature analysis. Forest Ecology and Management 310, 173-186. Langvatn R. and Hanley T.A. (1993) Feeding-patch choice by red deer in relation to foraging efficiency. Oecologia 95, 164-170. Marchiori E., Sturaro E., Ramanzin M. (2012) Wild red deer (Cervus elaphus L.) grazing may seriously reduce forage production in mountain meadows. Italian Journal of Animal Science 11, 47-53. Sankey T. (2012) Woody-Herbaceous-Livestock Species Interaction. In: Myster R.W. (ed.) Ecotones between forest and grassland, Springer Science+Business Media, New York, pp. 89-114.
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