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31.
Predators can create a “landscape of fear” that influences the spatial distribution of their prey. Understanding whether human activity similarly affects the distribution of species beyond habitat suitability is crucial but difficult to assess for conservation managers. Here, we assessed the effect of recreation and forestry activity on a threatened forest-dwelling umbrella species, the Capercaillie (Tetrao urogallus). We followed the citizen science approach on the landscape scale in the Bohemian Forest. We analyzed species data non-invasively collected through intensive fieldwork by volunteers and assessed human activity in the entire study area by analyzing expert questionnaires. The study area extends over 119,000 ha and harbors one of the largest relict populations of this grouse species in Central European low mountain ranges. Our statistical models revealed a negative impact of recreational activities on the intensity of habitat use of the birds within suitable habitats, thereby pointing toward a landscape of fear. The influence of forestry activity, in contrast, was not clear. In comparison to existing regional tourism impact studies, we were able to elevate the examination to the landscape scale. Our results underlined the relevance of recreation in limiting the species’ habitat on an entire landscape and allow us to conclude that habitat managers should set aside well-defined zones without recreational activities to preserve the refuge of this umbrella species. 相似文献
32.
Alkaline degradation of spruce and beech wood 总被引:1,自引:0,他引:1
V. Mašura 《Wood Science and Technology》1982,16(2):155-164
Summary The alkaline delignification of spruce and beech wood is accomplished in three phases. The first phase results in a decrease of yield down to 83...80%, the second one in a decrease from 83...80% to 64...61% and the third one in a yeld drop from 64...61% to 50...46%. The amount of polysaccharides removed in the first phase was 22%, in the second phase 5...6% and in the third phase 10% of the total polysaccharides in the original wood. The amount of lignin removed in the first phase of delignification was 9...11% in the second phase 53...54% and in the third phase 28% of the total lignin in the original wood. The polysaccharides extracted in the second and third phase amounted to 70...78% of the polysaccharides removed in the first delignification phase. For an entire characterization of the delignification reaction not only the course of lignin removal is of importance but also the course of the polysaccharide extraction. The results show that for a two-stage alkali-oxygen-cooking technology the optimum yield after initial partial alkaline delignification lies in the range of 64...61%. 相似文献
33.
E. Dax O. Livneh O. Edelbaum N. Kedar N. Gavish H. Karchi J. Milo I. Sela H. D. Rabinowit 《Euphytica》1993,74(1-2):159-163
Summary A RAPD marker, linked to the Tm-2
agene engendering TMV resistance in tomatoes, was identified. The validity of the RAPD marker was corroborated by screening several tomato varieties, and correctly identifying those which carried Tm-2
a, as well as by F2 segregation analysis. All tested resistant varieties descending from a common Lycopersicon peruvianum/esculentum ancestor, LA1791, exhibited this marker. 相似文献
34.
35.
The main question connected with developing wheat cultivars adapted to low nitrogen (N) is whether separate breeding programs for low and high input conditions are necessary. Nineteen wheat cultivars were grown over three years in Croatia in a total of eight environments at high N and low N in order to determine the effect of two N levels on means, variances and heritability of grain yield and bread-making quality and to assess the relative efficiency of indirect selection under high N in improving trait means under low N. Means of grain yield and grain protein content decreased under low N 10 and 13 %, respectively compared to the high N, whereas higher reductions of means due to lower fertilization were observed for grain N yield (21 %), wet gluten content (20 %), Zeleny sedimentation value (27 %) and for most rheological parameters, whose mean values were reduced from 20 % to as much as 57 %. Heritabilities for grain yield and grain N yield at high N were 0.82 and 0.76, respectively, and 0.77 and 0.43 at low N. Heritability for dough development time, stability and resistance also tended to be higher at high N than at low N due to a decrease in genetic variance and an increase in error variance at low N. The genetic correlation coefficients between high and low N were higher than 0.90 and the efficiency of indirect selection under high N for performance under low N was near 1.0 for grain yield and for most bread-making quality traits. 相似文献
36.
37.
Josef Suchomel Luboš Purchart Ladislav Čepelka 《European Journal of Forest Research》2012,131(6):1933-1941
Small-mammal communities were monitored over 4 years in South Moravian rural lowland forests in order to study relationships with various forest habitat types. Early successional sites (plantations) and forest edges maintained communities with higher abundance and diversity. Lowest total abundance was observed in unmanaged lowland forest and highest abundance in plantations with irregular undergrowth management. Low diversity was typical of non-fruiting monocultures. In plantations, both diversity and abundance were affected by herb layer removal, with sites subject to regular cutting, displaying lower levels. Significant differences in diversity and species richness were only detected between early and late successional sites, with the former showing higher values. Two basic small-mammal community groups were determined; (1) those inhabiting sites with a thick herb undergrowth and an open tree canopy (plantation) and (2) those inhabiting stands with sparse or no herb layer and a closed canopy (high forest). Forest stands support long-term populations of dominant small forest-dwelling mammal species and, as such, serve as reservoirs, even in rural landscapes dominated by intensive arable farming. Managed early succession lowland forests represent important refuges for a number of small open-habitat mammals negatively affected by intensive farming. 相似文献
38.
The scavenger activities of Equisetum arvense, Equisetum ramosissimum and Equisetum telmateia aboveground parts phosphate buffer (pH 7) extracts were evaluated using three different methods: DPPH assay, ESR and NO radical inhibition assay. Total reducing power was determined by FRAP assay. The E. telmateia extract demonstrated the most relevant scavenger and antioxidant properties. ESR signal of DMPO-OH radical adducts in the presence of E. telmateia phosphate buffer (pH 7) extract was reduced to 98.9% which indicated that E. telmateia could be a useful source of antioxidants with huge scavenger ability. 相似文献
39.
Blaise Ratcliffe Foster J. Hart Jaroslav Klápště Barry Jaquish Shawn D. Mansfield Yousry A. El-Kassaby 《Annals of Forest Science》2014,71(3):415-424
Context
Wood quality traits are important to balance the negative decline of wood quality associated with selection for growth attributes in gymnosperm breeding programs. Obtaining wood quality estimates quickly is crucial for successful incorporation in breeding programs.Aims
The aims of this paper are to: (1) Estimate genetic and phenotypic correlations between growth and wood quality attributes, (2) Estimate heritability of the studied traits, and (3) Assess the accuracy of in situ non-destructive tools as a representative of actual wood density.Methods
Wood density (X-ray densitometry), tree height, diameter, volume, resistance drilling, acoustic velocity, and dynamic modulus of elasticity were estimated, along with their genetic parameters, for 1,200, 20-year-old trees from 25 open-pollinated families.Results
Individual tree level heritabilities for non-destructive evaluation attributes were moderate ( $ {\widehat{h}}_i^2=0.37-0.42 $ ), wood density and growth traits were lower ( $ {\widehat{h}}_i^2=0.23-0.35 $ ). Favorable genetic and phenotypic correlations between growth traits, wood density, and non-destructive evaluation traits were observed. A perfect genetic correlation was found between resistance drilling and wood density (r G ?=?1.00?±?0.07), while acoustic velocity and dynamic modulus of elasticity showed weaker genetic correlations with wood density (r G ?=?0.25?±?0.24;?0.46?±?0.21, respectively).Conclusion
This study confirmed that resistance drilling is a reliable predictor of wood density in western larch, while the weak genetic correlations displayed by acoustic velocity and dynamic modulus of elasticity suggest limited dependability for their use as fast in situ wood density assessment methods in this species. 相似文献40.
R. Jakuš 《Journal of pest science》1998,71(8):152-158
A method and layout of various systems of barriers of pheromone traps is described. The rationale of the method is based on
the stress of spruce and the chemical communication ofIps typographus. Various systems of pheromone trap barriers were used according to the required level of protection. The method was used
in two areas affected by air pollution and bark beetle outbreak. The first area was in an unnatural spruce monoculture region
while the second was in a National Park.
The described method led to a significant reduction of bark beetle attacks on trees along forest edges and subsequently to
the stopping of movement of the zone of attacked trees due to bark beetle damage. In the case of forest stands with no reduced
canopy closure, the reduction of attacks led to a dramatic decline of bark beetle outbreak. On the other hand, this method
was not able to reduce the level of bark beetle attack in the interior of forest stands with a decreased level of canopy closure.
This method, as part of differentiated pest management measures in one forest district, was successful without any other protection
measures in the condition of natural reserves in a spruce vegetation zone. 相似文献