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In this study we investigated the relationship between the distribution patterns of a number of herbaceous plant species and the isolation and age of habitat patches. The study was conducted for a network of ditch banks in an agricultural landscape in The Netherlands. Thirteen plant species were selected representing contrasting dispersal and seed bank characteristics. Isolation of habitat patches was determined by the distance to the nearest occupied patch and by the number of occupied patches in circles of increasing radius around the patches. Age was the number of years since the creation of the ditches. In a multiple logistic regression model the separate effects of age of the habitat and the spatial variables were analyzed. A number of habitat variables were used to correct the effect of habitat quality. We concluded that distribution patterns of plant species were mainly determined by habitat quality and the presence of seed sources at short distances (< 25 m). This conclusion was independent of the dispersal characteristics of the species. Most species had higher occupation frequencies in older than younger ditch banks. Only species with persistent seeds had comparable occupation probabilities in older and younger habitat patches, indicating the importance of the soil seed bank as a source of colonization after large-scale disturbances. The effect of age and management on the occupation probabilities of the species was often diminished in the regression model, probably due to correlation between some habitat variables and the age of the patches

De te verwachten effecten van het Grensmaasproject op het gedrag van de rivier, zodat ook prognoses over de invloed op de bosontwikkeling mogelijk worden

In het kader van het onderzoeksproject 'Veehouderij en Natuur' wordt op ROC Zegveld onderzoek gedaan naar de inpasbaarheid van drie manieren van sloot(kant)beheer en het effect ervan op de vegetatie.

In this study we investigated the relationship between the distribution patterns of a number of herbaceous plant species and the isolation and age of habitat patches. The study was conducted for a network of ditch banks in an agricultural landscape in The Netherlands. Thirteen plant species were selected representing contrasting dispersal and seed bank characteristics. Isolation of habitat patches was determined by the distance to the nearest occupied patch and by the number of occupied patches in circles of increasing radius around the patches. Age was the number of years since the creation of the ditches. In a multiple logistic regression model the separate effects of age of the habitat and the spatial variables were analyzed. A number of habitat variables were used to correct the effect of habitat quality. We concluded that distribution patterns of plant species were mainly determined by habitat quality and the presence of seed sources at short distances (< 25 m). This conclusion was independent of the dispersal characteristics of the species. Most species had higher occupation frequencies in older than younger ditch banks. Only species with persistent seeds had comparable occupation probabilities in older and younger habitat patches, indicating the importance of the soil seed bank as a source of colonization after large-scale disturbances. The effect of age and management on the occupation probabilities of the species was often diminished in the regression model, probably due to correlation between some habitat variables and the age of the patches

De te verwachten effecten van het Grensmaasproject op het gedrag van de rivier, zodat ook prognoses over de invloed op de bosontwikkeling mogelijk worden

De te verwachten effecten van het Grensmaasproject op het gedrag van de rivier, zodat ook prognoses over de invloed op de bosontwikkeling mogelijk worden

Proefbedrijf Zegveld is in 1991 gestart met onderzoek naar sloot- en slootkantbeheer. In 1993 werd op drie demobedrijven gestart met vergelijkbaar onderzoek. Het sloot- en slootkantbeheer is gericht op verschraling en beperken van verstoring van de slootkanten. Hierdoor krijgen meer en bijzondere plantensoorten een kans. Zo leveren veehouderijbedrijven een bijdrage aan het natuurbeheer.

Proefbedrijf Zegveld is in 1991 gestart met onderzoek naar sloot- en slootkantbeheer. In 1993 werd op drie demobedrijven gestart met vergelijkbaar onderzoek. Het sloot- en slootkantbeheer is gericht op verschraling en beperken van verstoring van de slootkanten. Hierdoor krijgen meer en bijzondere plantensoorten een kans. Zo leveren veehouderijbedrijven een bijdrage aan het natuurbeheer.

In the modem arable landscape, the vegetation of perennial field boundaries have important ecological functions such as providing a habitat for farmland wildlife, providing overwintering sites for predatory insects, providing movement corridors, reducing soil erosion and acting as an agrochemical buffer. In recent decades, plant diversity in these linear landscape structures has declined severely. The present study aims at identifying the most important factors that control botanical species richness in herbaceous arable field boundaries. The field boundary vegetation is usually managed by farmers who consider the boundary to be a source of weeds. Therefore, research concentrated on factors that simultaneously increase species richness and reduce weed abundance in the boundary vegetation.Species richness was primarily affected by an accumulation of nutrients in the field boundary. Nutrients may reach the boundary in two ways: (i) by misplacement of fertilizer and (ii) by capture of arable nutrient resources (through root growth into the field) by plants in field boundaries. The high nutrient levels in the boundary resulted in an increased productivity of the vegetation and a dominance of tall, competitive species. Subsequently, low statured species disappeared from the habitat and species richness declined. The most common type of boundary management practiced by farmers did not include removal of the cut material after mowing which strengthens the eutrophication of arable field boundaries. Herbicide drift had adverse effects on species richness but the effects were less severe and consistent compared to the effects of nutrients.The main factor promoting weed growth (in the study area primarily the clonal weeds Cirsium arvense and Elymus repens) was the presence of bare soil in the boundary. Bare soil may be created by cultivation activities of the farmer or by the smothering effects of cut material left lying in the boundary after mowing. Bare soil generally promotes the establishment of annual weed species. Furthermore, the perennial weed Elymus repens was found to be able to concentrate its biomass selectiveley in bare patches within the perennial vegetation. Additionally, bare soil was found to favour the establishment of tall competitive (early successional) species compared to later successional species which are indicative of more species rich plant communities.The results of this study suggest that boundaries that are not regularly disturbed and low to moderately productive combine species richness with low weed abundance. This may be achieved by a regular and consistent mowing regime of the boundary vegetation that includes removal of the cuttings. A boundary management approach is suggested which may be combined easily with other farming activities.

This paper argues that not only should environmental and ecological benefits and economic costs be considered in developing nature conservation policies at the farm level but that farmers' perceptions should also be taken into account. Statistical analysis of survey data demonstrates the relevance of these behavioural aspects. Arable farmers with experience of unsprayed crop edges indicated that they preferred unsprayed edges in cereals or grass strips for agronomical, farming equipment related and socio-psychological reasons. The study also focused on the “ideal” unsprayed crop edge from the farmers' perspective. It appeared that a flexible width is most important for acceptance in farming practice, because it is, above all, the width that determines compatibility with existing farming organisation and parcel lay-out. In this respect, there was significant differences between regions. With regard to the payment system, farmers prefer a guaranteed reward instead of a “payment for nature” result, irrespective of the region considered.

In het kader van het onderzoeksproject 'Veehouderij en Natuur' wordt op ROC Zegveld onderzoek gedaan naar de inpasbaarheid van drie manieren van sloot(kant)beheer en het effect ervan op de vegetatie.

In het kader van het onderzoeksproject 'Veehouderij en Natuur' wordt op ROC Zegveld onderzoek gedaan naar de inpasbaarheid van drie manieren van sloot(kant)beheer en het effect ervan op de vegetatie.

Welke structuur en floristische samenstelling dient de begroeiing van een rivierdijk te hebben, die enerzijds een zo goed mogelijke waarborg biedt tegen aantasting door watererosie en anderzijds de natuurwaarde van dit biotoop zoveel mogelijk in stand houdt? 2. Welke voorwaarden dienen aan materiaal, ontwerp en uitvoering van dijkverhogingen en/of dijkverzwaringen gesteld te worden ten einde het sub 1. genoemde doel te bereiken? 3. Welk beheer dient na de sub 2. genoemde aanleg ten aanzien van de begroeiing gevoerd te worden?

Welke structuur en floristische samenstelling dient de begroeiing van een rivierdijk te hebben, die enerzijds een zo goed mogelijke waarborg biedt tegen aantasting door watererosie en anderzijds de natuurwaarde van dit biotoop zoveel mogelijk in stand houdt? 2. Welke voorwaarden dienen aan materiaal, ontwerp en uitvoering van dijkverhogingen en/of dijkverzwaringen gesteld te worden ten einde het sub 1. genoemde doel te bereiken? 3. Welk beheer dient na de sub 2. genoemde aanleg ten aanzien van de begroeiing gevoerd te worden?