Browsing by Subject "vegetation"
Now showing items 1-4 of 4
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(2013)Finnish agriculture has faced radical changes since the mid-20th century due to intensification of agricultural production. These changes have resulted into considerable wildlife habitat loss and degradation of biodiversity. Open ditches and their boundaries are one such habitat. They were widely replaces by subsurface drainage. This thesis aims to understand the role open ditches for agricultural biodiversity; what kinds of plants live the ditch habitat and can ditches enhance agrobiodiversity? To answer these questions we surveyed the vegetation of ditch slopes and ditch banks. Both vegetation composition and species richness were studied. The survey concerns only vegetation, but it is assumed that plant species diversity supports diversity of other groups of organisms. The data was collected in summers 2008 and 2009 in Lepsämä river catchment in Southern Finland in co-operation with MYTVAS (Significance of the Finnish agri-environment support scheme for biodiversity and landscape) -project. Ditch habitat characterization was done by studying the most common species and their indicative values in the data. Also NMS-ordination graph was created. Environmental variables were analyzed too. According to the literature review ditches can have significant role in maintaining agrobiodiversity, and their existence has probably reduced biodiversity loss. However, the vegetation analysis shows that the study area was species-poor and homogenous. Probable explanations are the habitat’s humidity and high levels of nutrients alongside the dominance of few strong weed species. In order to improve ditches as wildlife habitats their quality should be enhanced. For example fertilizer and herbicide drifts should be reduced and ditch banks could be widened. Also tending the ditch habitat by cutting or grazing are highly recommendable methods to enhance biodiversity.
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(2015)Conservation biological control is a strategy of biological control that aims to support natural enemies of pests. One of the potential ways to support natural enemies is to enhance diversity in agricultural landscapes. By establishing non-cultivated areas near crop fields natural enemies can be provided with many resources including food, shelter and overwintering sites. The availability of these resources potentially enhances the abundance and diversity of natural enemies and their efficiency to reduce pest populations. The goal of this study was to compare the effects of two different fallow strip types – meadow strip and grassland strip – on the abundance and species composition of predatory arthropods. To examine the differences between the strip types, data were collected from the strips and adjoining cereal fields. An experiment was conducted on two barley fields in Helsinki in summer 2014. Two fallow strips were established in the middle of each field. The strips were composed of four 3 m * 60 m-sized plots. Every other plot was sown with meadow seed mixture and every other with grassland mixture. Data on predatory arthropods were collected during June-July using pitfall traps. There were more predatory arthropods on the fallow strips than on the barley fields. However, there were no differences in the abundance of predatory arthropods between the fallow strip types. Moreover, the abundance of predatory arthropods on adjoining cereal field did not differ between the strip types. The species composition of predatory arthropods differed statistically significantly between barley fields and the fallow strips, and almost significantly between the strip types. The results indicate that the fallow strips succeeded to provide favorable habitats for predatory arthropods, which may be due to food or shelter that they provide. The lack of clear differences on the abundance and species composition of predatory arthropods between the strip types can be explained by the fact that the vegetation of the strips was not yet fully established in the first year. Other reasons include the substantial differences between the two study fields. However, it seems that fallow strips have potential to provide biodiversity benefits, which have previously been observed in environmental fallow fields, and to enhance ecosystem services such as biological control.
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(2013)Loss of biodiversity in the Finnish agricultural environment has increased during the last decades due to the agricultural intensification. Accurate, efficient and repeatable sampling methods are important to follow the impacts of the measures to enhance biodiversity. This study focuses on the assessment of vegetation structure and species diversity. Vegetation cover is one of the most common measures to assess vegetation biodiversity. Cover data is usually collected by a point intercept method, a line intercept method or by visual estimation in quadrats. Traditional methods have been found to be laborious, time-consuming and subjective, and having poor repeatability. The main objective of this study was to find out if it is possible to improve vegetation surveys with digital photographs and an object-based image analysis. To answer this question, a visual method (VM) was compared with a photographic method (PM). The VM was based on ocular estimation of the total vegetation cover. In the PM, pictures of the top cover were taken vertically downward from 1.5 meters above the ground. Using a software program called Definiens, the photographs were divided into segments, which were then classified into bare ground, litter, monocots and dicots to estimate the covers for each category. The data was collected during the summer 2010 from environmental fallows and set-asides. There was a clear correlation between the cover measures in the VM and the PM, so it can be assumed that the PM is suitable for the assessment of the vegetation cover. However, using only the PM, it is not possible to get a reliable estimate of the vegetation structure or species diversity. It was faster to collect the data in the field with the PM than with the VM. The computer used in this survey was inefficient, thus the image analysis took more time than expected and as a result the PM was in its entirety slower than the VM. The study gave important theoretical and practical information about the photographic method, its strengths and weaknesses. Photographic methods are still under development and further research is needed but they hold promise for the future.
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(2011)Environmental fallows were added as a new voluntary scheme to the agri-environmental programme in Finland in 2009. The scheme aims, among other things, to benefit farmland biodiversity by providing resources for wildlife, and to protect soil from erosion and nutrient leaching. There are four types of environmental fallows: long-term grassland, game crop field, landscape plant field and meadow plant field. In 2010, they covered in total over seven per cent of the field area in Finland. It is important to evaluate the impacts of environmental fallows on environment and develop the scheme, in order to make effective use of resources put into it. The goals of this study were to find out, how important environmental fallows are for biodiversity in agricultural landscapes; what kind of fallows are the most valuable for biodiversity; and how the scheme should be developed. In order to answer these questions, the species richness and composition of vascular plants as well as vegetation structure were surveyed on environmental fallows in Uusimaa and North Ostrobothnia regions in summer 2010. Additionally, the vegetation of environmental fallows was compared with the vegetation of semi-natural meadows and field edges surveyed in another study. Information on the study fields, e. g. parcel history, establishment and management, was collected through a farmer questionnaire. Meadow fields that are sown with low-competitive seed mixtures proved to be the most species rich of the environmental fallow types. On grasslands and meadow fields, the fertility of soil was negatively correlated to the number of species. In species composition the four types of environmental fallows differed from each others as well as from seminatural meadows and field edges. So, the scheme probably enhances diversity in landscape scale. However, there were few rare plant species on environmental fallows. Today, the big majority of the environmental fallows are long-term grasslands, which reduces their positive impact on landscape and biodiversity. The value of environmental fallows both for nature, farmers and society can be enhanced by developing seed mixtures and establishment and management methods as well as offering more advice for the farmers.
Now showing items 1-4 of 4