Traditional Mowing Research Articles

Assessing montane grassland and butterfly biodiversity to improve management strategies in locally significant conservation areas

Montane grasslands must be managed effectively to conserve biodiversity since they play an important role in sustaining healthy and diversified ecosystems. A 9 km transect was used to assess plant and lepidopteran biodiversity in mountain meadows in Bilbor, Romania. Different management strategies were used in each plot. The identified plants were divided into three categories: Poaceae, Fabaceae, and other families. In the case of lepidoptera, diurnal butterfly species from three families were observed: Lycaenidae, Nymphalidae, and Pieridae. The number of plant species in the abandoned meadows was reduced, with a focus on those with low fodder value (Nardus stricta and Deschampsia flexuosa), as well as some invasive species (Vaccinium myrtillus). The implementation of protection and conservation measures resulted in species diversification, with an increase in the number of Poaceae (11 to 16 species) and Fabaceae (nine to fourteen species). In addition to providing more feed, the flora can benefit lepidopteran entomofauna. During the monitoring period, 29 species were identified from the three lepidopteran families. The most abundant species were Maniola jurtina L., Boloria selene Denis & Schif., Argynnis paphia L., Coenonympha pamphilus L. (Nymphalidae), Pseudophilotes schiffermuelleri Hemming (Lycaenidae), and Pieris mannii Mayer (Pieridae). Traditional mowing and grazing activities can help to maintain the structure and composition of these ecosystems, limiting biological succession to forest and sustaining floristic biodiversity.

Fast grassland recovery from viable propagules after reintroducing traditional mowing management on a steep slope

Semi-natural grasslands on steep slopes often show high plant species diversity. These grasslands were traditionally maintained through mowing and/or grazing. The traditional management practices help to maintain species diversity, whereas land abandonment reduces diversity by increasing competition from dominant species and reducing seedling recruitment. The reintroduction of management can reverse species diversity declines, but suitable grassland restoration programs are scarce in Japan. To study the effect of short-term abandonment on seedling ecology, we monitored the vegetation of a Susogari grassland that had been abandoned for 3 years; the grassland occupies a steep slope (ca. 50°) on a hillside above paddy fields, and was traditionally mown. We monitored the vegetation before abandonment, in the 3rd year of abandonment, and in the 1st and 2nd years after restoration of mowing management. Emergence and survival of seedlings was monitored for 18 months after reintroduction of management. We monitored 1,183 seedlings of grassland species and non-target annuals in ten 1-m2 plots. After mowing was reintroduced, most grassland species reappeared or increased in the first and second years. Few seedlings of perennial plants and no seedlings of annuals flowered. An exotic species, Solidago altissima, had a lower survival rate (10%) than grassland species (>30%), and all but two grassland species survived over the 18-month period. Although vegetation composition was not fully recovered, our findings suggest that a steep slope acts as a strong filter that inhibits the establishment of non-target species while enhancing persistence of target grassland species.

Effects of habitat management on newly found populations of the endangered weed, Mummenhoffia alliacea (Brassicaceae)

AbstractGarlic pennycress (Mummenhoffia alliacea) is a rare weed of the Brassicaceae family, protected in Hungary. In 2021, three new sites of the species were discovered. In addition to these previously unknown occurrences, a detailed study of a roadside occurrence known for a longer time but not yet published was carried out. Main aim of our study was to find out how habitat management practices, such as mowing and winter‐deicing effects seed mass and germination. Seeds collected earlier had significantly lower mass than those from later collections, suggesting that late‐spring mowing would be optimal for the reproduction of M. alliacea. The type of mowing (chopping the stem into small pieces or cutting the stem at one point at few centimetres above ground) had no significant effect on seed germination but did have a significant effect on the seed mass. Seed mass deriving from whole individuals was significantly higher than seed mass of chopped individuals, suggesting, that traditional mowing methods are better than the use of modern lawnmowers for the survival of the species. The highest NaCl (used for winter‐deicing) concentration where germination was observed was 0.75 m/m% (mass percentage), which is comparable with strongly saline soils in nature. The newly discovered sites were all disturbed, one of which was located on roadsides (paved and dirt roads) and two on embankments, suggesting that anthropogenic habitats could be optimal for the species, but the long‐term survival depends on the management of these habitats.

Responses of grassland productivity to mowing intensity and precipitation variability in a temperate steppe.

Mowing for hay is an important land use in grasslands that is affected by precipitation variability, due to the water-limited nature of these ecosystems. Past land use and precipitation conditions can have legacy effects on ecosystem functions, potentially altering responses to both mowing and precipitation. Nonetheless, it is still unclear how natural variation in precipitation will affect plant responses to changes in mowing intensity. We conducted a seven-year field experiment with three mowing intensity treatments compared to the traditional mowing intensity (5cm stubble height) as a control: increased mowing (2cm stubble), decreased mowing (8cm stubble) and ceased mowing. Decreased mowing increased both plant aboveground net primary productivity [ANPP] and forage yield across the whole community, driven by increases in graminoids, mainly owing to the positive response of plants to precipitation. Both mowing disturbance and precipitation variability had legacy effects on plant ANPP; however, these responses differed among the whole community, graminoid, and forb levels. Current-year community-wide ANPP [ANPPn] was positively associated with current-year precipitation [PPTn] in all mowing treatments, driven by positive precipitation responses of the dominant graminoids. For forbs, however, ANPPn was negatively associated with prior-year growing season precipitation [PPTn-1] across mowing treatments, potentially due to lagged competition with the dominant graminoids. Our results suggest that the response of the dominant graminoids is the primary factor determining the response of ANPP to mowing and precipitation variability in these grassland ecosystems, and highlight that decreasing mowing intensity may maximize both herder's income and grassland sustainability.

The effect of accidental burning on habitat conditions and species composition of Molinion caeruleae meadows

This study aimed to assess the effects of accidental burning on plant cover and habitat conditions in abandoned Molinion caeruleae meadows. Field studies were conducted in Kraków (Southern Poland) in the years 2017–2019 in two line transects, each with 10 permanent plots established in permanent study plots placed in accidentally burned and unburned patches. In the burned patch, the number of species, as well as Shannon-Wiener, Pielou and Simpson indicators achieved lower values. Moreover, the cover of numerous taxa affiliated with Molinion caeruleae changed remarkably, while taxa representing the alliances Calthion and Filipendulion disappeared. The considerable dominance of hemicryptophytes was observed in burned site, while in unburned place hemicryptophytes and geophytes were represented most abundantly. In the burned patch, anemochorous and autochorous species as well as small-seeded taxa dominated, while in the unburned patch autochorous species and medium-seeded taxa prevailed. The values of Ellenberg indicators in the burned patch achieved greater (light, soil reaction), lower (nitrogen, humidity) or similar (temperature, continentality) values to the unburned patch. The majority of soil properties in the burned and unburned patches were similar with the exception of the significantly greater content of potassium and lower content of magnesium in exchangeable form noticed in the burned patch. The performed investigations showed that, although the accidental fire activity inhibited the secondary succession in Molinion caeruleae meadows, burning cannot replace traditional mowing due to the reduction of species richness and disappearance of characteristic taxa.

Effect of Rudbeckia laciniata invasion on soil seed banks of different types of meadow communities

In the last decades, biological invasions become the main driver of biodiversity loss. The changes can be noticed not only in the above-ground diversity but also in the underground, including seed banks of native vegetation. In this study, we focus on Rudbeckia laciniata, a species introduced to many European and Asian countries, to characterize its soil seed bank as well as to answer the question, how the species influenced soil seed banks of meadow plant communities in two types of habitats (fresh and wet), where traditional mowing was abandoned. Within the habitats, we conducted our study on a three-step scale of invasion, from full invasion, through the transition zone to the control zone, where no invasion of the species has been observed so far. The majority of the R. laciniata seeds were located in the surface layer of soil. We detected, that 47% (in fresh meadow) and 56% (wet meadow) of recorded species occurred only in a soil seed bank, and were absent in aboveground vegetation. Emergence of native plants from the soil seed bank is low due to rapid shading of the soil surface by R. laciniata seedlings. However, a short-term seed bank of the species gives hope that returning to regular mowing brings the desired results in its the elimination from vegetation, in a fairly short time.

Temporal Variations in the Production—Quality and Optimal Cutting Date of Hay Meadows in the Central Pyrenees (Spain)

The production and forage quality of semi-natural hay meadows of Arrenatheretalia in the southern central Pyrenees were studied according to the time of mowing within the vegetative cycle, to determine its optimum moment. The results show important variations according to the meadows and the year. Higher productions (56% in kg DM ha−1, 42% in UFL ha−1) and lower qualities (−12% in CP, −11% in UFL kg DM−1, −7% in PDI and −17% in RFV) were obtained in the year in which temperatures and rainfalls were the highest. It is concluded that the timing (advance or delay) concerning the maximum value of production and the quality (two years) do not have a direct relationship with the variations of accumulated rainfalls and the growing degree days. The decreases in production (18% in kg DM ha−1 and 25% in UFL ha−1 until 24 June) and quality (26% in CP, 16% in UFL kg DM−1, 13% in PDI and 20% in RFV until 24 June) were also quantified from their maximum values within the traditional mowing period. The optimal time for mowing is between 20 May and 20 June, depending on the annual weather and the meadow characteristics.

Mowing in agri-environmental schemes (AES) and rare species of Vertigo snails: hope for grasslands but a threat to snails

Four Vertigo species are covered by special forms of protection under Annex II of the Habitats Directive. The habitats of these snails are currently rare in Europe. Since typical conservation practices are ineffective for this ecosystem, support mechanisms for measures maintaining biodiversity have been incorporated into agriculture in the form of agri-environmental schemes (AES). However, an inappropriately designed AES may threaten the survival of populations of globally endangered species such as Vertigo moulinsiana (Dupuy) as mowing and swath removal dates coincide with the snails’ activity period in the upper parts of the mown plants, the majority of their population will be removed from the area along with the harvested swath. In addition, mowing instantaneously and radically alters the habitat’s microclimate. The policy of mowing the total area thus leads to unprecedented habitat homogenisation across the landscape, especially when machine mowers are used. In the case of V. moulinsiana, the best approach would be not to mow the whole area but to leave a part unmown where these snails could live unhindered. Instead of machines, traditional mowing could be implemented, which entails cutting at a greater height above the sedge clump level. This would not destroy the tussock structure and would allow the habitat to recreate itself. In combination with the designation of unmown refuges, the effects of this approach could be quite beneficial to the snails.

Long-term ecology and conservation of the Kungur forest-steppe (pre-Urals, Russia): case study Spasskaya Gora

The Kungur forest-steppe is the northernmost outpost of European forest-steppe, located in the western pre-Urals within the boreal climatic zone. The co-existence of boreal, nemoral and steppe species with relicts and endemics results in a high plant diversity, making it an important biodiversity hotspot. Under current climate change and strong agricultural impacts, the Kungur forest-steppe is rapidly degrading. In order to develop sustainable management strategies, we studied the vegetation history over the last 3500 years in the natural reserve area Spasskaya Gora. Palynological data indicate that the territory of Spasskaya Gora was largely covered by hemiboreal forests with high proportion of elm during the late Holocene. An opening of the vegetation strongly correlates with erosion, both indicating anthropogenic activities such as lumbering, agriculture, grazing and hay making. The modern Pinus and Betula dominated forests combined with large areas dominated by grasses and herbs appear in the last 300 years and caused by human activity. The data support the ‘anthropogenic’ hypothesis of the Kungur forest-steppe development, suggesting that Pleistocene steppe was replaced by hemiboreal forests during the Holocene. Steppe elements survived on exposed rocks. The recent forest-steppe landscapes dominated by pioneer birch and poplar were formed due to anthropogenic deforestation. With respect to nature conservation, our data demonstrate that prohibition of any anthropogenic activities at Spasskaya Gora will lead to loss of diversity of steppe assemblages over the mid-term. We emphasize that conservation of the high plant diversity of the Kungur forest-steppe must include disturbance factors in the form of selective lumbering, prescribed burning, moderate grazing or traditional mowing.

Case Study of an Automated Mower to Support Airport Sustainability

This paper documents a case study of an automated mower to support sustainability at an airport. Mowing is an essential component of an airport’s Wildlife Hazard Management Plan (WHMP), which reduces the risk of birds and other wildlife to aircraft operations. Many airports have large areas of land (hundreds or even thousands of acres), which requires significant resources to manage and mow; experience at the Purdue Airport (KLAF) suggests that automated mowing may support economic and environmental aspects of sustainability. Automated mowing supports economic efficiency by reducing personnel requirements, although personnel are still needed for inspections, maintenance, and “mower rescue” if there is a malfunction (technical or field issue). Automated mowing supports environmental impacts by reducing local emissions since the mower is powered by electricity rather than gasoline; this benefit would be increased with the use of solar-powered mowers. Automated mowing may not be viable everywhere, and factors such as terrain, access to available power, acreage, and location on the airfield (including proximity to protected areas) must be carefully considered. Although automated mowing will not completely replace traditional mowing in the near future, autonomous mowers in remote areas may be an appropriate practice to support airport sustainability.

Hidden below‐ground plant diversity buffers against species loss during land‐use change in species‐rich grasslands

AbstractQuestionsTheory suggests that while plant diversity of grasslands decreases in response to increased competition for light, many plant species persist below‐ground even in the temporary absence of shoots. Thus, we hypothesized that below‐ground, diversity is less affected by increased competition during land‐use change compared to above‐ground.LocationSpecies‐rich, oligotrophic grasslands in the Železné hory Mts, eastern Bohemia, Czech Republic.MethodsWe quantified above‐ and below‐ground plant richness (roots and rhizomes, seed and bud bank) in grasslands subjected to seven years of experimental abandonment and fertilization. We used conventional species identification to measure richness above‐ground and 454 sequencing of the chloroplast trnL (UAA) gene to measure richness of roots and rhizomes; additionally, we used the shoot emergence method to measure soil seed and bud bank richness.ResultsWhile above‐ground richness decreased with abandonment and fertilization, below‐ground richness remained less affected or even increased compared to the control (traditional mowing). Overall, compared to above‐ground the proportion of plant species found only below‐ground as roots and rhizomes increased, particularly in the abandonment with fertilization treatment.ConclusionsBelow‐ground plant diversity could potentially buffer against biodiversity losses during short‐term land‐use change. Our findings highlight that measuring the complete plant species diversity improves our understanding of processes that underlie plant diversity and coexistence and refine predictions of vegetation responses to biodiversity threats.

Water-soluble carbohydrates in Patzkea paniculata (L.): a plant strategy to tolerate snowpack reduction and spring drought in subalpine grasslands.

In subalpine grasslands of the central French Alps, cessation of traditional mowing promotes dominance of Patzkea paniculata (L.) G.H.Loos (Poaceae) tussocks, with high biomass but low fodder quality. Mowing limits P.paniculata abundance through the depletion of its water-soluble carbohydrate (WSC) reserves, which sustain early spring growth initiation. However, the effectiveness of mowing effects is modulated by grassland functional composition, fertilization and climate change, as WSC compounds, and notably fructans, support plant physiological responses to climate stresses such as drought or frost. To characterize the mechanisms underpinning the control of P.paniculata under global change, we tested the effects of climate manipulation (combined snow removal and drought) and management (cutting and fertilization) alone or in combination on P.paniculata WSC storage in assembled grassland communities of varying functional composition. Management and climate treatments individually decreased seasonal fructan storage, with neither additive nor synergic effects between them, primarily due to the dominance of management over climate effects. Fructan amounts were higher in individuals growing in unmanaged exploitative communities compared to unmanaged conservative communities, regardless of climate treatments, but management overrode these differences. Our findings suggest that reduction by combined snow removal and drought of P.paniculata carbon allocation to WSC storage may similarly limit its dominance to that in current mowing practices.

Traditional semi-natural grassland management with heterogeneous mowing times enhances flower resources for pollinators in agricultural landscapes

For a diverse pollinator fauna it is important that pollen and nectar are available over the entire summer at spatially relevant scales. Semi-natural hay meadows are among the most important sources of flower resources for pollinators, but the resources are strongly affected by the timing of mowing. Management recommendations for hay meadows often prescribe late mowing on order to allow undisturbed flowering during most of the summer. Traditional practices, however, often include also earlier mowing. We investigate the link between the temporal variation of flower resources and traditional mowing practices of semi-natural hay meadows in a low-intensity agricultural landscape in Romania. In early August, we botanically surveyed meadows that were cut early, intermediately, or late in the season. We recorded all herb species, their phenological stage, and the number of reproductive units of each species. Data were analysed using DCA, LM and GLM. Plant species richness and composition are not affected by the time of mowing, but different sets of species flower in semi-natural grasslands with different mowing regimes. In August the proportion of species flowering and flower density are highest in the early-mown meadows due to re-flowering after mowing. Analyses of phenological stages indicate that late-mown meadows are the main pollen and nectar sources in July, whereas meadows mown early are the main resource from August to the end of the season. The results demonstrate that for pollinator conservation, heterogeneous mowing times within a landscape need to be encouraged when possible, and that strict focus on late mowing may lead to shortage of flower resources late in the summer. Studies of low-intensity agriculture has a great potential for learning about management methods that can be used in other parts of the world where traditional practices have been lost. Such studies can thereby contribute with important knowledge to manage global pollinator loss.

Evaluating alternative mowing regimes for conservation management of Central European mesic hay meadows: A field experiment

Conservation status of hay meadows highly depends on their management. The main goal of this study was to assess the efficiency of different mowing regimes in maintenance of plant species richness and diversity of mesic hay meadows. The field experiment was carried out on a species rich, mesic hay meadow in Western Hungary. We evaluated the effects of four alternative types of management on the plant community after 7 years of continuous treatment: (1) mowing twice a year, typical traditional management, (2) mowing once a year in May, most practised currently by local farmers, (3) mowing once a year in September, often proposed for conservation management and (4) abandonment of mowing. Traditional mowing resulted in significantly higher number and higher diversity of vascular plant species than other mowing regimes. Mowing twice a year was the only efficient way to control the spread of the invasive Solidago gigantea, and mowing in September was more successful in it than mowing in May. We conclude that the traditional mowing regime is the most suitable to maintain botanical diversity of mesic hay meadows; however, other regimes should also be considered if certain priority species are targeted by conservation.

Quantifying the diversifying potential of conservation management systems: An evidence-based conceptual model for managing species-rich grasslands

The differential effect of main grassland management types (primarily grazing and mowing) on plant species richness has been discussed in many papers. In-depth investigations, focusing on the effects of particular management attributes (herbage removal intensity, timing, etc.) are less frequent. We propose a new, evidence-based conceptual model for quantifying the specific effects of particular management attributes on the richness and diversity of plant species. The applicability of the model was tested in Central-Hungarian species-rich meadow-steppe grasslands, characterised by different management regimes. Two management attributes involved in this study (herbage removal intensity and spatio-temporal complexity of management regime) significantly affected both the diversity and the plant species richness at a 1m2 spatial scale, whereas management type had a significant effect on species richness only. With regard to the overall variance in species richness, none of the single attributes (without combining with other ones) had considerable explanatory power; for making precise predictions, all the management attributes must have been considered. The “dichotomous effect” of grazing (i.e. both the highest and the lowest levels of plant species richness were observed at pastures) could be quantitatively explained by the model. Grazing at low or medium intensity (less than 0.5 animal unit/ha), with an annually varying rotation sequence of pasture units, led to a much higher, whereas permanent overgrazing resulted in a much lower, level of plant species richness than traditional mowing (conducted once a year during midsummer). Generalisation of the proposed model can be used to predict the potential overall effect of particular management systems on the plant species richness of other grassland types. For the potential overall effect of management, a new term has been introduced: the diversifying potential.

Contrasting response to mowing in two abandoned rich fen plant communities

Globally important U.K. fens are in poor condition, principally due to abandonment, following cessation of traditional mowing and grazing in recent decades. In the absence of management, rich fen flora are displaced as a result of succession. This leads to an increase in competitive species and subsequent biomass accumulation. In order to reverse this trajectory and increase species richness, management consisting of a single mowing event was employed. Mowing was conducted in two degraded fen communities in north-west Wales (U.K.) across three sites: (i) a species rich, tussock alkaline mire, dominated by Schoenus nigricans and Juncus subnodulosus (SN community) and (ii) a species poor basin mire Cladio-Molinietum dominated by Cladium mariscus (CM community). The early vegetation responses were monitored over two years. Results show a large treatment effect on species richness in the CM community, where mean species richness increased by 51% in the second year following mowing. Consequently, total species number across all sites increased to 74 in the treatment compared to 44 in the control. Mowing reduced vegetation height and litter cover and increased bare ground. These treatment effects combined with a reduction in graminoid and shrub cover collectively contributed to the initial stages of rehabilitation. Conversely, the SN community showed no increase in species richness, in spite of a reduction in litter cover and increased bare ground. Strong site heterogeneity and a sustained canopy height caused by rapid re-growth of the dominant graminoid S. nigricans may have impeded treatment effects. Therefore, increased mowing frequency in alternate years, switching between autumn and summer would be necessary to develop species richness in the SN community. Ongoing intervention in each fen community is needed to achieve an optimal trajectory of increased rich fen and reduction of secondary succession species.

Drought-induced shifts in plants traits, yields and nutritive value under realistic grazing and mowing managements in a mountain grassland

Extreme drought events can dramatically impact grassland ecosystems, causing potential loss of forage production for livestock in temperate grasslands. However, knowledge of drought effects on forage production, nutritive value and plant community stability in the real context of farming management is scarce. For this purpose, the effect of a simulated summer drought was studied under two realistic management types on a semi-natural grassland in the Swiss Jura mountains. The first management (“grazing”) consisted in six consecutive utilizations by animals over the growing season, representing a rotational grazing system as regionally conducted. The second management (“mowing”) consisted of three harvests, corresponding to the usual mowing frequency of hay meadows. In both managements, drought caused minor short-term modifications of species composition and almost no persistent effects were observed. Besides, important short-term changes were observed in community weighted mean of several key functional traits, reflecting a strong decline in community growth during the drought followed by a partial recovery two months later. Forage yields, and to a lesser extent its nutritive value, thus declined during the drought period. Both were still affected in the following months, but had recovered in spring of the following year. Forage loss was twofold higher in the grazing management, but recovery as well as nutritive value was slightly improved in this management. The results suggest that rotational grazing can amplify negative drought impacts, compared to traditional mowing, and highlight the need to adapt such management in dry years. They also demonstrate that, even under a fairly intensive management, resilience of such mountain grasslands after one extreme drought event can be expected to be high, with no persistent changes in species and trait compositions.

Land abandonment and intensification diminish spatial and temporal β‐diversity of grassland plants and herbivorous insects within paddy terraces

Summary Although traditional land‐use and management practices are known to enhance environmental heterogeneity in agricultural lands, loss of heterogeneity resulting from recent land‐use changes can lead to spatiotemporal β‐diversity losses (biotic homogenization). However, patterns and causes of β‐diversity loss, especially at a within‐field scale, have remained unexplored. We examined β‐diversity declines in plants, butterflies and orthopterans resulting from land abandonment and intensification in semi‐natural grasslands on paddy margins at a within‐field scale in relation to changes in disturbance frequency and surrounding landscapes by surveying eight abandoned, thirteen traditional and ten intensive paddy terraces. Three indices, the additive partitioning of species richness (βadd) and the turnover (βtu) and nestedness (βne) components of Jaccard dissimilarity of plants and herbivores, were used to evaluate different aspects of β‐diversity. We hypothesized that biotic homogenization due to abandonment and intensification would be expressed as low spatiotemporal βadd and βtu, low spatial βne and high temporal βne. The spatial and temporal βadd of plants and herbivores were higher in traditional terraces than in others. Changes in mowing frequency caused direct declines in butterfly βadd and indirectly decreased herbivore βadd through diminished plant βadd in abandoned and intensified terraces. Neighbouring forests increased plant spatial and butterfly temporal βadd and βtu. Abandoned terraces had higher orthopteran spatial and plant temporal βtu than traditional terraces. Mowing frequency generally did not influence spatial and temporal βtu of plants and herbivores. In intensive terraces, temporal βne of plants were higher than in traditional terraces, suggesting dominance by plant species sharing similar phenologies. Synthesis and applications. These results suggest that traditional mowing practices are essential for maintaining plant and herbivore βadd, and consequently, species pools within terraces. The higher spatial or temporal species turnover of plants and orthopterans in abandoned terraces and higher temporal plant nestedness in intensive than in traditional terraces were not due to increases in species pools within terraces. Because within‐terrace environmental heterogeneity is thought to remain in abandoned and intensive terraces, we recommend reduction in mowing frequency in intensive terraces and reintroduction of mowing in abandoned terraces for biodiversity restoration.

Conservation management in fens: Do large tracked mowers impact functional plant diversity?

Cessation of traditional mowing management has been the main threat to fen biodiversity for many decades; shrubs and trees expand and target plant and animal species decline. In Biebrza National Park (BNP), the EU’s largest conservation area of alkaline fens, abandonment has affected more than 300km2. To combat unwanted succession, tracked mowers were developed based on snow grooming vehicles and are increasingly used in BNP and some other European fens. While effects on bird populations seemed promising, the impact on botanical diversity remained yet unknown. We assessed the effects of this management on vegetation by comparing 12 pairs of mown and unmown plots (percentage cover recorded from 4m2 for all species and 25m2 for rare species) spread over several km2. We found that tracked vehicles suppressed some species, which are likely to facilitate others by providing shelters above groundwater level (hummock mosses, tussock sedges and shrubs) and enhanced species with effective clonal spread and high specific leaf area. An even stronger increase was observed in forbs, which share effective clonal spread and flood tolerance (high Ellenberg F value). Analysis of functional diversity indices based on all measured traits showed a decrease of functional divergence due to mowing (indicating convergence of traits) and no response of functional richness, evenness and functional dispersion. Mowing has also decreased the number of rare species. We associate these changes with the reduction of micro-topography by caterpillar tracks. Tracked mowers should therefore be avoided in those fens, in which microtopography contributes to unique botanical diversity.

Effects of mire type, land use and climate on a strongly declining wetland butterfly

Mires are characterised by highly specialised and threatened wildlife. One of these mire specialists that has severely declined is the Large Heath (Coenonympha tullia). However, detailed studies concerning the reasons for the dramatic population loss in central Europe are missing so far. In this paper: (1) we analyse the habitat preferences of adult C. tullia and oviposition site selection with respect to mire type and land use in one of the last German strongholds, and (2) we attempt to disentangle the impacts of land use and climate change on the decline of C. tullia on a national scale across Germany. Abundance of adult C. tullia was clearly affected by mire type and land use. It was highest on managed calcareous fens and lowest on unmanaged transition and raised bogs. The oviposition pattern of C. tullia females was best explained by (1) quantity of potential host plants (Eriophorum latifolium), (2) vegetation structure, and (3) microclimate. In Germany, C. tullia populations have become extinct in lowlands with a mild and relatively dry climate while most colonies in wet and cold mountain areas have survived. However, there is evidence that habitat loss and habitat deterioration, rather than climate change, are the drivers of the range retraction. To create low-growing vegetation rich in E. latifolium, traditional mowing late in the year and light grazing seem to be suitable management tools. In addition, conservation management should aim to maintain high water levels or restore them, especially to counteract effects of climate change in the future.