Semi-natural Open Habitats Research Articles

Impacts of forest extent, configuration and landscape context on presence of declining breeding Eurasian curlew Numenius arquata and implications for planning new woodland

In response to the combined impacts of the climate and biodiversity crises, as well as for timber security and increased recreational access to green spaces, there is a global drive to increase tree cover. In the UK, an estimated 1.5 million ha of afforestation are required to meet its carbon net-zero emissions targets (Committee on Climate Change, 2018). Despite the potential benefits, careful consideration must be given to the impacts of woodland creation on species adapted to open habitats. To investigate potential risks and mitigation for the IUCN Near Threatened Eurasian curlew Numenius arquata, a national spatially extensive field-scale dataset was used to investigate the relationships between curlew presence during the breeding season and a range of forest and landscape variables at two different spatial scales (0.5 km and 1 km). Variables included forest extent and configuration, and interaction between forests and extent of semi-natural open habitats, moorland management and topography. At both spatial scales, a negative relationship existed between extent of forest and the probability of curlew presence, and at 1 km, between probability of presence and the number of forest patches. However, these negative patterns depended on landscape context and were reduced where there was a greater quantity of semi-natural open habitat, such as moorland or rough grassland, and moorland management present. Overall, the findings emphasise the need to consider the impacts of woodland creation projects on species adapted to open habitats. However, the results suggest that these impacts can be influenced by landscape. These results could help inform decisions regarding the appropriateness of woodland creation in different landscapes and possible mitigation measures that could be applied against the risks created by afforestation.

Breeding biology of Red-backed Shrikes (Lanius collurio): distribution, performance and post-fledging survival in Denmark

Agricultural intensification and habitat degradation across Europe have caused declines since the 20th century in populations of birds adapted to open landscapes, such as the Red-backed Shrike (Lanius collurio). Effective conservation strategies require knowledge on species’ breeding biology. To understand the status of the Danish breeding population better, we investigate which factors affect their breeding parameter (i.e. distribution, performance, post-fledging survival and behaviour). Our focus on the post-fledging period addresses present knowledge gaps due to the importance of this, yet under-studied, phase of passerines’ breeding cycle. We studied breeding pairs on different habitat types with Denmark-wide Citizen Science data, complemented by data of local projects in Northern Zealand and Northern Jutland (Denmark). Significantly fewer pairs were found in agricultural habitats and more in forests, semi-natural open habitats and synanthropic habitats. Pairs in forests had a significantly higher breeding productivity compared to agricultural or semi-natural open habitats for data from the years 2000 to 2021. Some project sites showed significantly higher number of fledglings compared to others, indicating that these sites are potential core areas for breeding productivity. Over the last two decades, the mean breeding productivity across Denmark was stable with 2.3 fledglings per successful pair. The survival rate of ringed fledglings increased during the post-fledging period, likely due to their increase in more active and independent behaviour. The relatively low breeding productivity found in this study calls for further studies including detailed data from potentially secondary habitats like agricultural areas to understand the effects of habitat on population fluctuations.

Grazing by wild red deer can mitigate nutrient enrichment in protected semi-natural open habitats

Eutrophication through atmospheric nutrient deposition is threatening the biodiversity of semi-natural habitats characterized by low nutrient availability. Accordingly, local management measures aiming at open habitat conservation need to maintain habitat-specific nutrient conditions despite atmospheric inputs. Grazing by wild herbivores, such as red deer (Cervus elaphus), has been proposed as an alternative to mechanical or livestock-based measures for preserving open habitats. The role of red deer for nutrient dynamics in protected open habitat types, however, is yet unclear. Therefore, we collected data on vegetation productivity, forage removal, quantity of red deer dung and nutrient concentrations in vegetation and dung from permanent plots in heathlands and grasslands (eight plots à 225 m2 per habitat type) on a military training area inhabited by a large population of free-ranging red deer over one year. The annual nutrient export of nitrogen (N) and phosphorus (P) by red deer grazing was higher than the nutrient import through red deer excreta, resulting in an average net nutrient removal of 14 and 30 kg N ha−1 a−1 and 1.1 and 3.3 kg P ha−1 a−1 in heathlands and grasslands, respectively. Even when considering approximate local atmospheric deposition values, net nutrient depletion due to red deer grazing seemed very likely, notably in grasslands. Demonstrating that grazing by wild red deer can mitigate the effects of atmospheric nutrient deposition in semi-natural open habitats similarly to extensive livestock grazing, our results support the idea that red deer are suitable grazing animals for open habitat conservation.

Seed ecology of European mesic meadows.

European mesic meadows are semi-natural open habitats of high biodiversity and an essential part of European landscapes. These species-rich communities can be a source of seed mixes for ecological restoration, urban greening and rewilding. However, limited knowledge of species germination traits is a bottleneck to the development of a competitive native seed industry. Here, we synthesize the seed ecology of mesic meadows. We combined our own experimental data with data obtained from databases to create a combined dataset containing 2005 germination records of 90 plant species from 31 European countries. We performed a Bayesian meta-analysis of this dataset to test the seed germination response to environmental cues including scarification, stratification, temperature, alternating temperature and light. We also used multivariate ordination to check the relationship between seed traits (germination and morphology) and species ecological preferences, and to compare the seed ecology of mesic meadows with that of other herbaceous plant communities from the same geographic area. The seed ecology of mesic meadows is characterized by (1) high seed germinability when compared with other herbaceous plant communities; (2) low correspondence between seed traits and species ecological preferences; and (3) a deep phylogenetic separation between the two major families, Poaceae and Fabaceae. Poaceae produce many light seeds that respond to gap-detecting germination cues (alternating temperatures and light); Fabaceae produce fewer heavy seeds, which need scarification to break their physical dormancy. High germinability of meadow seeds will reduce their capacity to form persistent seed banks, resulting in dispersal limitations to passive regeneration. For centuries, human activities have shaped the regeneration of meadows, leading to a loss of seed dormancy and decoupling seeds from seasonal cycles, as has been found in many domesticated species. The same anthropic processes that have shaped semi-natural mesic meadows have left them dependent on continued human intervention for their regeneration, highlighting the importance of active restoration via seed supply.

Returning home after fire: how fire may help us manage the persistence of scrub-steppe specialist bird populations

Semi-natural open habitats have drastically changed in the last few decades due to agricultural intensification and rural depopulation. Steppe-birds, and especially those adapted to primary stages of vegetation succession, are threatened by an increase in scrub cover, and management actions are being applied to reverse scrub encroachment and restore habitat suitability in semi-natural open habitats. In this paper we evaluated for the first time, the long-term effects of a wildfire on habitat structure, vegetation productivity, and the associated response of an endangered scrub-steppe specialist bird, the Dupont’s Lark Chersophilus duponti. Wildfire occurred in a Mediterranean steppe of central Spain dominated by permanent community of dwarf cushions scrubs. Bird abundance was evaluated by line transects in the burnt and unburnt areas 3 years prior to the fire and 4 and 7 years after the fire. We quantified changes in habitat structure at fine scale level through vegetation sampling points and in vegetation productivity by estimating the Normalized Difference Vegetation Index (NDVI). Fire had strong effects for at least up to 4 years after the fire, when lower NDVI values, less scrub cover and fewer, but not significant, number of males were detected in the burnt area with respect to the pre-fire conditions. Seven years after fire most vegetation variables measured did not differ between areas, number of males detected within the burnt area was recovered and NDVI values in burnt area were slightly recovered but were significantly lower than in control area. Slow regeneration of the scrub cover after fire explained the unsuccessful occupation of the burnt area by the Dupont’s Lark up to several years after fire. The more dispersed and shorter habitat created by fire 7 years after the fire seems to be more suitable for the species than that in control areas. The large number of males around the burnt area may have played a role in the recolonization process. In sum, vegetation recovery and the presence of a low scrub-steppe specialist, as the Dupont’s lark, suggests that fire management could be integrated into conservation plans to effectively manage scrub encroachment processes in Mediterranean scrub-steppes.

Dung beetle (Coleoptera: Scarabaeoidea) assemblages in the western Italian Alps: benchmark data for land use monitoring.

BackgroundTraditional agro-pastoral practices are in decline over much of the Alps (MacDonald et al. 2000), leading to shrub and tree encroachment, and this represents one of the main threats for the conservation of alpine biodiversity, as many plant and animal species are dependent on the presence of semi-natural open habitats. However, quantifying this environmental change and assessing its impact on biodiversity may be difficult, especially in the context of sparse historical survey data. The accessibility of contemporary data about local biodiversity surveys in general, and indicator taxa in particular, is an essential consideration for planning future evaluations of conservation status in the Alps and for conservation plans that use ecological indicators to monitor temporal changes in biodiversity. Dung beetles are important ecosystem service providers (Nichols et al. 2008) that have been assessed as a good ecological indicator taxon in several studies (reviewed by Nichols and Gardner 2011), and although the Alps is perhaps one of the best-studied regions in respect of dung beetles, there are still only eight readily-accessible publications. We have augmented and comprehensively reviewed the data from these publications.New informationWe first provide data about changes on a temporal scale of seasons in a dung beetle community in the western Italian Alps, an issue that has to be addressed in the local assemblages because it would affect regional biomonitoring and conservation research. This survey of 12 099 individuals belonging to 22 species illustrates a distinct seasonal pattern at a single site. Second, we collate the results of 13 published surveys of the presence of 46 species of dung beetles in 11 valleys in the western Italian Alps in the period from 2005 to 2012, a period of accelerated change in land use that started around 1945 (MacDonald et al. 2000). Because ten of the surveys used baited pitfall traps and four more used manual collection of specimens, the abundance data were not strictly comparable and they were therefore transformed to binary data (presence-or-absence records) with measures of sampling effort. The results illustrate both spatial variation and temporal variation at the scale of years.Because of the importance of dung beetles in agro-pastoral ecosystems and the high sensitivity of montane ecosystems to climate change, these spatially and temporally explicit data sets provide important baseline information about western Italian Alpine dung beetles for investigations of the effects of land use change under ongoing climate change scenarios.

Mapping an ecological network of green habitat patches and their role in maintaining urban biodiversity in and around Debrecen city (Eastern Hungary)

Urbanisation is a leading process on the Globe causing a massive loss of natural habitats. In parallel variety of habitats were created in urban environments, which may also support species diversity. Our aim was to identify urban green areas and their connections with the Regional Ecological Network surrounding the city of Debrecen (East-Hungary), and to explore the biodiversity potential of the network of these parks. We found that whilst industrial areas, airport and mixed land covered a relatively large area, parks and other functional green spaces had a relatively small extent. However the green space system of the city is well connected to the Regional Ecological Network. We also surveyed the functional and potential green spaces in the city and in the studied patches of the Regional Ecological Network in and around the city. We found that 65% of the functional green spaces are potentially connected thus there is a possibility for species typical to semi-natural open habitats to disperse between the green spaces of the city. Based on the survey of the spontaneous flora and planted ornamentals we found that the ratio of native species was high in the studied urban parks. We found that native species were the most typical (>50%) in the spontaneous flora of the studied urban parks, although the ratio of archaeophytes and neophytes were also high. Among ornamental plants, both the proportion of native species and neophytes were considerable in each park, and the proportion of archaeophytes was low. Our results suggest that the studied urban habitats have some biodiversity conservation potential; they mostly harbour species which can cope with the local environmental conditions of the city parks, such as increased temperature, drought and nutrient enrichment.

Butterflies take advantage of contemporary forestry: Clear-cuts as temporary grasslands

Contemporary forest landscapes in boreal and temperate environments, harvested by clear-cutting, contain various novel types of open spaces which are potentially suitable for species inhabiting natural or semi-natural open habitats. However, systematic analyses identifying the share of the regional species pool that can take advantage of this opportunity are missing. We assessed the importance of such forest openings for open-habitat butterflies in Estonia in Northern Europe by comparing butterfly species richness and composition in forest clear-cuts with their regional species pool. The species richness of butterflies in clear-cuts appeared to be remarkably high: we recorded altogether 81% of the total regional species pool across the study sites. Clear-cuts were inhabited by a very high share (79%) of regionally occurring grassland species, as well as nearly complete sets of open-habitat generalists and forest species. Redundancy analysis showed that clear-cuts in forests with different environmental characteristics harbour distinct butterfly assemblages, their contribution to the butterfly fauna in forest landscapes being thus complementary. This as well as several other lines of evidence indicate that most butterfly species can form resident populations in harvested forest landscapes. Our findings demonstrate that considering novel types of forest openings as ‘temporary meadows’ can substantially improve the conservation prospects for butterflies and other organisms that have traditionally been considered to inhabit grasslands and other open habitats in agricultural landscapes. Human-altered ecosystems may thus prove to be a viable alternative where restoring or maintaining natural and semi-natural habitats is impossible.

Conservation Value, Management and Restoration of Europe’S Semi‑Natural Open Landscapes

Abstract Most semi-natural open habitats in Europe have been traditionally maintained by anthropogenic activities, such as grazing or mowing, preventing the establishment of woody vegetation. These habitats harbour a remarkably rich biodiversity in terms of both plant and animal species, but are also highly threatened, mainly by agricultural intensification and land abandonment. With this Editorial we introduce a Special Issue initiated by the European Dry Grassland Group (EDGG) at the Open Landscapes Conference (Hildesheim, 2013) and the 11th European Dry Grassland Meeting (Kulikovo Pole, 2014). We aim to give a short introduction to the current conservation status, significance and research of semi-natural open habitats in Europe and present the collected articles of the Special Issue. These papers cover a wide range of different semi-natural open habitats, including wood-pastures, heathlands, steppes, semi-dry and dry grasslands across the Palearctic region and address issues related to the assessment methods, threats, management and restoration of these habitats. We conclude that, in order to ensure their conservation and to monitor the changes in open habitats, integrative approaches are needed that take into account not only vegetation records, but also multiple animal taxa, abiotic factors, management practices, ecosystem services and modelling simulations for anticipating possible future scenarios. We also recommend that decision-makers should support actions to conserve open habitats in Europe by addressing such major challenges as the encroachment of woody vegetation. We are convinced that the present Special Issue will contribute to a better understanding of ecosystem functions and support the biodiversity conservation and management of semi-natural open habitats.

Combining Approaches to Support High Nature Value Farmland in Southern Transylvania , Romania

Abstract The region of Tarnava Mare in Southern Transylvania contains extensive semi-natural open landscapes maintained by predominantly low-intensity farming, which is widespread in Romania and indeed many areas of Eastern Europe. Threats to these species-rich habitats from agricultural intensification and land abandonment have been increasing in recent years, to a large extent linked with Romania’s accession to the EU in 2007. At the same time, however, the opportunities for biodiversity conservation in the area have expanded. In 2008, the region became a Site of Community Importance (SCI) as part of the Natura 2000 network, and farmers have applied agri-environment schemes as part of the EU Common Agricultural Policy since 2006. Furthermore, the Tarnava Mare region has been the location of several EU and nationally funded projects combining research, practical and information measures. In this article, we review these various instruments from the practical perspective of an NGO that has been working since 2004 to support High Nature Value farmland and rural communities in this region. We focus on three major support measures - agri-environment schemes, Natura 2000, and publicly funded conservation projects - and consider their effects individually and collectively. We conclude that the presence of multiple instruments can have synergistic effects on the conservation of semi-natural open habitats such as HNV farmland, and that this overlap provides a certain amount of resilience: if one instrument fails, another may fill the gap. Cross-cutting projects combining research with activities to tackle the “problem” of the socio-economic undesirability of low-intensity farming as well as the “symptom” of the loss of HNV farmland are also particularly important in this context.

クロマツ二次林の林床・林縁植生における秋季の結実種数および種子数の経時変化

Application of seed-containing plant material is a successful technique to transfer plant species onto restoration sites. However, this restoration method is almost confined to semi-natural open habitats. Plant material mown from understory and edge vegetation of a secondary Japanese black pine (Pinus thunbergii Parlat.) forest was taken in three different dates (September, October and November) to assess the ability of propagule recruitment in such closed habitats. Both the number of seed-produced species and the amount of seed were small in September compared with those in October and November. This is due to the fact that most species were under early stage of their flowerings, suggesting that September is inappropriate for harvesting seeds from plant community in this study site. Although many grassland species were recorded in both understory vegetation and edge vegetation, the number of produced seeds was clearly smaller in understory vegetation for most of grassland species, demonstrating that understory vegetation was inappropriate for the seed-containing plant material, due largely to the shortage of photon flux density.

Prescribed burning and browsing to control tree encroachment in southern European heathlands

Land abandonment and the cessation of traditional management practices is favouring scrubland and forest expansion throughout Europe, reducing the extent of many semi-natural open habitats of a high ecological value. Tree encroachment is threatening several Calluna vulgaris (L.) Hull heathlands. The objective of this study was to analyze vegetation dynamics resulting from an experiment designed to test management options aiming at controlling the encroachment of Populus tremula (aspen) and favouring heathland recovery. The research was conducted at Vauda Heath, North-western Italy, from 2005 till 2009. We studied prescribed burning and goat browsing, both alone or in combination, assessing their effects on structure and density of encroaching trees, as well as on heathland main species, C. vulgaris and Molinia arundinacea. Treatments were applied to 42 experimental units (300–650m2 each), with each treatment combination replicated from six to twelve times (including untreated controls).Prescribed burning and browsing showed complementary effects on post-fire vegetation development. Both back and head fire behaviors were effective in inducing stem mortality of aspen and rejuvenating the heathland, but in the absence of measures to control post-fire suckering, aspen tended to recover the pre-treatment stand structure. A higher fire frequency (annual winter fire) controlled tree encroachment, but hindered Calluna recovery, whilst favouring competing grass species. Goat browsing alone was initially able to reduce tree growth and slow down woodland expansion, until aspen individuals reached an escape size of 1.5m in height. Prescribed burning followed by yearly goat browsing effectively contained tree encroachment while maximizing post-fire heathland regeneration. This integrated approach thus proved its efficacy also at the southern limits of Calluna distributional area.

Impacts of Land Abandonment on Vegetation: Successional Pathways in European Habitats

Changes in traditional agricultural systems in Europe in recent decades have led to widespread abandonment and colonization of various habitats by shrubs and trees. We combined several vegetation databases to test whether patterns of changes in plant diversity after land abandonment in different habitats followed similar pathways. The impacts of land abandonment and subsequent woody colonization on vegetation composition and plant traits were studied in five semi-natural open habitats and two arable habitats in six regions of Europe. For each habitat, vegetation surveys were carried out in different stages of succession using either permanent or non-permanent plots. Consecutive stages of succession were defined on a physiognomic basis from initial open stages to late woody stages. Changes in vegetation composition, species richness, numbers of species on Red Lists, plant strategy types, Ellenberg indicator values of the vegetation, Grime CSR strategy types and seven ecological traits were assessed for each stage of the successional pathway. Abandonment of agro-pastoral land-use and subsequent woody colonization were associated with changes in floristic composition. Plant richness varied according to the different habitats and stages of succession, but semi-natural habitats differed from arable fields in several ecological traits and vegetation responses. Nevertheless, succession occurred along broadly predictable pathways. Vegetation in abandoned arable fields was characterized by a decreasing importance of R-strategists, annuals, seed plants with overwintering green leaves, insect-pollinated plants with hemi-rosette morphology and plants thriving in nutrient-rich conditions, but an increase in species considered as endangered according to the Red Lists. Conversely, changes in plant traits with succession within the initially-open semi-natural habitats showed an increase in plants thriving in nutrient-rich conditions, stress-tolerant plants and plants with sexual and vegetative reproduction, but a sharp decrease in protected species. In conclusion, our study showed a set of similarities in responses of the vegetation in plant traits after land abandonment, but we also highlighted differences between arable fields and semi-natural habitats, emphasizing the importance of land-use legacy.