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The interactive effects of various nitrogen fertiliser formulations applied to urine patches on nitrous oxide emissions in grassland

{array} $ N. As a result, N can be efficiently utilised by the pasture before it becomes available for loss. This argument is further supported by the high N 2 O and EF values from the CAN fertiliser group, where half of N is already in the N O 3 − $\begin{array}{} \displaystyle \rm NO_3\,^- \end{array} $ N form. Comparison of disaggregated and re-aggregated emissions with aggregated cumulative emissions Fertiliser is commonly applied to pastoral soils shortly after grazing, meaning some of it is applied to fresh urine patches. In intensive and semi

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Additive genetic, non-additive genetic and permanent environmental effects for female reproductive performance in seasonal calving dairy females

from the current rate of only 77% of heifers ever calving within their lifetime, as well as increasing the proportion of heifers calving within 26 months of birth. The presence of genetic variation for heifer calving rate traits support the argument for publishing the breeding values of heifer calving rate traits to identify sires that have more daughters entering the herd. Genetic correlations between the heifer calving rate traits and other nulliparae reproductive traits were generally strong and favourable, owing to the part–whole relationship between nulliparae

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Lennukilidari ja spektraalse kaugseireandmestiku kasutamine metsa peamiste takseertunnuste hindamiseks Aegviidu katsealal / Estimation of main forest inventory variables from spectral and airborne lidar data in Aegviidu test site, Estonia

Abstract

Field measurements from 450 sample plots, airborne lidar data and spectral images from Aegviidu, Estonia, 15 by 15 km test site were used to analyse options to estimate main forest inventory variables using remote sensing data. Up to 7 m random error in location of 15 m radius sample plots within homogeneous stands causes usually about 0.5 m standard deviation in lidar pulse return height distribution percentiles. Forest mean height can be predicted with linear relationship from 80th percentile of lidar pulse return height distribution. Upper percentiles of pulse return height distribution are not significantly affected by omitting returns from ground and forest understorey vegetation. Total stem volume in forest can be predicted by using 80th percentile, 25th percentile and canopy cover as model arguments with less than 70 m3 ha-1 standard error. Best species specific stem volume models had 10 m3 ha-1 smaller standard error.

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What is the use of the research carried out on the permanent plots in the Białowieża National Park?

Abstract

The purpose of the strictly protected area of the Białowieża National Park (BNP) established in early 1900s, was to protect a compact block of the Białowieża forest from any direct human influence and activity. Its founders considered it a ‘laboratory of nature’ In 1936, five rectangular plots with a total area of 15.5 ha (ca. 0.3% of the BNP) were set up for regular monitoring of stand development with regards to the initial state and variability of soil conditions. During the first 76 years of the project, a steady increase in the proportion of hornbeam and lime tree at the expense of shade-intolerant species was observed. This trend has been interpreted by the researchers involved in the monitoring of the permanent BNP plots to constitute a biodiversitythreatening development caused by preservation efforts. Such an interpretation has been widely incorporated in the public debate by political authorities and the forestry sector. In this critical article I challenge the major arguments presented by the key expert in silviculture, Prof. B. Brzeziecki. My criticism is directed at the methodological approach as well as at the data interpretation.

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Why do foresters oppose the enlargement of the Białowieża National Park? The motivation of the State Forests Holding employees as perceived by social actors engaged in the conflict over the Białowieża Forest

Abstract

This study outlines the main motives of foresters opposing the enlargement of the Białowieża National Park to include areas managed by the State Forests Holding. The motives were identified using discourse analysis tools based on the semistructured interviews with 36 people representing various groups of actors engaged in the discussion on the management of the Białowieża Forest. The main motives I found are connected to: (1) a vision of how nature should be and the foresters’ mission; (2) fear of losing employment or getting a worse job; (3) the high esteem of the forester profession in local communities and an inferior vocational status of the national park employees; (4) defending the professional prestige of foresters and the State Forests Holding; (5) competition with national parks over natural areas; (6) forest science; (7) the wish to continue hunting in the Białowieża Forest; (8) bottom-up pressure on the State Forests Holding employees. The major conflict potential in the discourse around the Białowieża Forest is connected with the perception of its unique natural values and methods of protection. As a result, two opposing coalitions have formed: one supporting forestry interests and one encouraging conservation. The discourse of the forestry-supporting coalition is strengthened by an epistemic community of forest scientists. Some arguments presented by the foresters pushing for a continuation of forest management in Białowieża also indicate the involvement of path dependency, which, in combination with large differences between the coalitions, does not allow for optimism regarding the resolution of the conflict.

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Evaluation of the corridor method for oak (Quercus sp.) cultivation using research objects in the Mircze and Kościan Forest Districts as an example

Abstract

The corridor method of oak (Quercus sp) cultivation is an old, forgotten silvicultural method. It was developed around the turn of the 19th and 20th century on the south-eastern borders of Poland (Podole, Wołyń) and Russia and made use of other species such as hornbeam, linden and birch as a cover for oak, which is a tree species sensitive to frosts. The nowadays recurring phenomenon of oak disease initiated a search for silvicultural alternatives and thus the usefulness of reviving the corridor method for oak regeneration was investigated by examining existing tree stands established in this way. Our research plots were located in five young stands and two in mature as well as old stands.

In the stands of the 2nd and 3rd age classes, the density of oaks was observed to be 1500–3500/ha, which accounted for 30–50%. The density of oak in old stands (7th age class) was similar to model-predicted values. Furthermore, the corridor method gave very good production results as exemplified by the oak stands growing on the fresh broadleaved site, which had a very high stand quality index. In addition, the species composition was observed to diversify throughout these oak stands’ development, thus supporting arguments for the conservation and preservation of oak-hornbeam forests. To summarise, the prerequisites for the success of the corridor method are systematic cuts of young stands (forest cultures and thickets) to inhibit the growth of accompanying undesired species and limiting the number of grazing animals.

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Forest ecosystem services – assessment methods

Abstract

Forest ecosystems represent the most important values of natural assets. In economic valuation techniques, to estimate the value of forest ecosystem services, the attention is still focused mainly on their market values, i.e. the value of benefits measured in the economic calculation based, first of all, on the price of timber. The valuation of natural resources is currently supported by considerations of the global policy, in order to strengthen the argumentation justifying the need to incur expenditure related to the protection of biodiversity. There is increasing evidence that biodiversity contributes to forest ecosystem functioning and the provision of ecosystem services. Natural capital of forests can be consumed directly as food, wood and other raw materials or indirectly – by benefitting from purified water and air, safeguarded soils or protected climate. At the same time, forest ecosystems provide us with a range of intangible values – scientific, cultural, religious as well as encompass heritage to pass on to future generations. In the era of increasing pressure on the use of free public goods (natural resources), it is necessary to improve understanding of the role of forests in creating national natural capital, and in enhancing the quality of human life. All things considered, the so called non-market forest ecosystem services may have a much higher value than the profits from the production of timber and raw materials. Needless to say, non-market values of forest ecosystems are of great importance for the quality of human life, and the awareness of this should translate into social behavior in the use of natural resources. This paper reviews the methods to estimate the value of forest ecosystem services in view of recently acknowledged paradigm to move forward from economic production to sustainable human well-being.

Open access
Natural Occurence of Deoxynivalenol and Ochratoxin a in Conventional Maize Hybrids and their Biosafety Compared with GM Equivalents

Abstract

Familiarity based approval of the newly developed GM cereal events is based upon the stable and safe consumption of conventional grains. The level of concentrations of mycotoxins and biomolecules establishes the criteria for premarket evaluation of genetically modified cereals e.g. MON 810 maize. The objective of the present study was to comparatively evaluate food biosafety of the conventional and GM maize. Grain samples from the harvest lot of 10 maize hybrids in the year 2011 were collected arbitrarily. Well ground and homogenized samples were analysed for the deoxynivalenol (DON) and ochratoxin A (OTA) mycotoxins. Contamination rates and levels of DON and OTA were low and did not exceed the maximum levels, indicating their possible safe use as food and feed under the EC regulation 1881/2006.The samples were further analysed for the possible effect of mycotoxin concentration upon that of starch and proteins. The study reveals the absence of any negative impact of the presence of mycotoxins upon these biomolecules as their concentrations lie within the normal range. A comparative review of data for the mycotoxins in conventional maize grains invalidate the argument from the producers of GM maize hybrids that conventional hybrids are inferior for food biosafety with respect to mycotoxins.

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Forest management and hunting in areas adjacent to national parks: the example of the Magura National Park

Abstract

the aim of the study was to evaluate arguments for hunting and its impact on forest management and conservation in national parks as well as areas directly adjacent to them. the issue was examined using the example of the Magura national Park (MnP) for which data on the number of deer and predatory mammals included in the statistical yearbooks for 2013-2014 were available. the quality and size of the food sources provided by this type of forest habitat were evaluated using data obtained from the literature. We also included data on the dietary habits of wolves and lynxes as well as their impact on the number of large ungulates in our analysis. the maximum carrying capacity of forest stands in the Magura national Park was determined to be 789 deer units (dear unit = 1 red deer or 0.3 elk or 5 roe deer), whereas in fact in 2014, the abundance of ungulates reached a total of 1230 deer units. our analysis evaluating the impact of wolf and lynx populations on ungulates in the area showed that these predators can kill up to 212 deer per year (140 individuals by wolves and 72 by lynxes). the growth in deer population, however, varies from 25.8% to 27.7%, which in the MnP amounts to 258-277 new born individuals per year, meaning that the wolf and lynx populations in the MnP are not able to prevent the number of deer from growing. the current population of ungulates (1230 deer units ) having reached a density of 6.6 deer units/km2 exceeds the capacity of the MnP and thus poses a real threat to maintaining both, the nature of the park and the adjacent stands. this article shows that the natural maintenance of balance in the predator-prey relationship is unlikely under these conditions and failure to allow for anthropogenic interference to regulate the number of ungulates in protected areas may result in an increase in the density of their population. Potential destruction of other valuable assets such as forest habitats may consequently follow. the current population of ungulates (1,230 deer units) having reached a density of 6.6 deer units/km2 exceeds the capacity of the MnP and thus poses a real threat to maintaining the nature of both the park and the adjacent stands. this article shows that the natural maintenance of balance in the predator-prey relationship is unlikely under these conditions and failure to allow for anthropogenic interference to regulate the number of ungulates in protected areas may result in an increase in the density of their population. Potential destruction of other valuable assets such as forest habitats may consequently follow.

Open access
A strict maximum likelihood explanation of MaxEnt, and some implications for distribution modelling

Distribution modelling - research with the purpose of modelling the distribution of observable objects of a specific type - has become established as an independent branch of ecological science, with strong proliferation of approaches and methods in recent years. Since it was first made available to distribution modellers in 2004, the maximum entropy modelling method (MaxEnt) has established itself as a state-of-the-art method for distribution modelling. Default options and settings in the user-friendly Maxent software has become established as a standard practice for distribution modelling by MaxEnt.

A mini-review of 87 recent publications in which MaxEnt was used with empirical data to model distributions showed that the ‘standard MaxEnt practice’ is followed by a large majority of users and questioned by few. However, the review also provides indications that MaxEnt models obtained by the standard practice are sometimes overfitted to the data used to parameterise the model; examples of cases in which simpler MaxEnt models with predictive performance do exist. Results of the review motivate strongly for a better understanding of the ecological implications of the maximum entropy principle, as a basis for choosing MaxEnt options and settings.

This paper provides a thorough explanation of MaxEnt for ecologists, ending with a set of suggestions for improvements to the current practice of distribution modelling by MaxEnt. The explanation for MaxEnt given in the paper differs from previous explanations by being based on the maximum likelihood principle and by being based upon a gradient analytic perspective on distribution modelling. Four new findings are particularly emphasised: (1) that a strict maximum likelihood explanation of MaxEnt is possible, which places MaxEnt among regression methods in the widest sense; (2) that the true degrees of freedom for the residuals of a Max- Ent null model is N - n, the difference between the number of background and the number of presence observations used in the modelling; (3) that likelihood-ratio and F-ratio tests can be used to compare nested MaxEnt models; and (4) that subset selection methods are likely to be preferential to shrinkage methods for model selection in MaxEnt. Methods for internal model performance assessment, model comparison, and interpretation of MaxEnt model predictions (MaxEnt output), are described and discussed. Two simulated data sets are used to explore and illustrate important issues relating to MaxEnt methodology.

Arguments for development of a generally applicable ‘consensus MaxEnt practice’ for spatial prediction modelling are given, and elements of such a practice discussed. Five main additions or amendments to the ʻstandard MaxEnt practiceʼ are suggested: (1) flexible, interactive tools to assist deriving of variables from raw explanatory variables; (2) interactive tools to allow the user freely to combine model selection methods, methods and approaches for internal model performance assessment, and model improvement criteria, into a data-driven modelling procedure, (3) integration of independent presence/absence data into the modelling process, for external model performance assessment, for model calibration, and for model evaluation; (4) new output formats, notably a probability-ratio output format which directly expresses the ʻrelative suitability of one place vs. anotherʼ for the modelled target; and (5) development of options for discriminative use of MaxEnt, i.e., use of with presence/absence data. The most important research needs are considered to be: (1) comparative studies of strategies for construction of parsimonious sets of derived variables for use in MaxEnt modelling; and (2) comparative tests on independent presence/absence data of the predictive performance of MaxEnt models obtained with different model selection strategies, different approaches for internal model performance assessment, and different model improvement criteria.

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