Priority Habitat Type Research Articles

Optimising Juniperus excelsa (Cupressaceae) germination for sustainable ecosystem restoration in the Prespa area (Western Macedonia, Greece)

In the Mediterranean Region, species of the genus Juniperus face conservation challenges due to human activities and climate change threats. Juniperus species are reported to present low regeneration rate, while their seeds often exhibit physical and physiological dormancy. Viability and germination of mature Juniperus excelsa seeds from population originating from the Prespa area (Florina, Greece), alongside with seedling survival were investigated to study the reproduction dynamic of species population known to represent a EU priority habitat type of limited distribution and with low regeneration rate. The seed cut test of an uncleaned seed lot revealed a high percentage of empty seeds (90.03%) and a low embryo viability (2%). Cleaned seeds were subjected to a total of 44 pretreatments, categorised into eight groups targeting physical and physiological dormancy, along with combinations of these techniques. Despite most treatments showing limited success in enhancing germination, three pretreatments exhibited promising results (germination between 22.22% and 39.40%). Subsequent germination tests involving these treatments in controlled chambers, as well as in field conditions, along with hydration-dehydration cycles, were conducted using newly collected seeds. Seed germination rates in controlled chambers remained low, suggesting a deep primary dormancy. Pretreated seeds, under controlled field conditions, passed two winter periods fully saturated, with 13 hydrating-dehydrating cycles in-between. Germination was maximised during the second year of the field experiment, reaching almost 100% after mechanical scarification for 6 sec., followed by immersion in 3% H2O2 for 2 h. However, seedling survival was low, reaching approximately 38.26%. The findings emphasise the challenges in germinating Juniperus excelsa seeds and highlight the importance of the optimised protocols for reforestation in order to conserve this habitat type.

The role of livestock grazing in long-term vegetation changes in coastal dunes: a case study from the Netherlands

The vegetation of coastal sand dunes is characterized by high species diversity and comprises some of the rarest vegetation types in North-Western Europe. Among them are dune grassland communities whose species richness relies on grazing. Those communities are assessed as a priority habitat type under the Natura 2000 legislation. In autumn 1990, Galloway cows and Nordic Fjord horses were introduced in the coastal dunes of Meijendel near The Hague (52°7'N, 4°20'E), The Netherlands, to reduce encroachment of tall grasses and shrubs, to develop bare sand patches, and as such facilitating diverse vegetation structures in the dune grasslands. In the 1950s, decades before the introduction of livestock, 41 permanent plots were installed. On average, they were examined every four years. Our study hypothesised that the livestock grazing in the set densities would halt progressive succession and facilitate regressive succession. Up to 1990, we observed an equilibrium between progressive and regressive succession. After 1990, however, our data showed a pronounced progressive succession contradicting the hypothesized effect of the livestock grazing. We relate the main observed patterns with two factors linked to rabbit populations: (i) the myxomatosis outbreak in 1954 and (ii) the rabbit Viral Haemorrhagic Disease (rVHD-1) outbreak in 1989. In addition to livestock grazing, rabbits block progressive succession by feeding on seedlings of shrub and tree species and digging burrows, creating small-scale mosaics of bare sand and initiate blowout development when collapsing. We state that the substantial decrease in rabbit numbers due to the viral diseases likely caused the observed increase of shrubs and trees in the study area's permanent plots. Climate change might have contributed to the observed increase in autonomous blowout development since 2001, as well as a decrease in atmospheric nitrogen deposition since 1990, after a strong increase the decades before.

Vegetation of the coastal dunes and wetland of Schinias National Park (NE Attica, Sterea Ellas, Greece)

Abstract The vegetation developing on the coastal sand dunes and wetland of Schinias National Park, a Natura 2000 Site, was studied following the Braun-Blanquet method. Vegetation units were delimited using cluster analysis and by applying the fidelity measure; the phi-coefficient was used for the definition of diagnostic species. The vegetation types distinguished (twenty associations, two sub-associations and thirteen communities not assigned formal rank), which belong to 18 alliances, 16 orders and 12 classes, are discussed and presented in phytosociological tables. Among them Mathiolo tricuspidatae-Anthemidetum tomentosae, Pistacio lentisci-Pinetum halepensis pinetosum pineae, Puccinellio festuciformis-Aeluropetum litoralis cressetosum creticae and Tamaricetum tetrandrae are described for the first time. The vegetation types recognized in the study area are linked to twelve EUNIS habitat types, nine of which are related to 13 Annex I habitat types (Directive 92/43/EEC), and one to a habitat type of national interest (72A0). One Annex I habitat type occurring in the study area has scattered presence in the Natura 2000 network in Greece (1420), two are infrequent (2190, 2260), two are rare (2230, 2270) and three are priority habitat types (1150, 2250, 2270).

Assessing the Heterogeneity and Conservation Status of the Natura 2000 Priority Forest Habitat Type Tilio–Acerion (9180*) Based on Field Mapping

Priority habitat types (HTs) within the Natura 2000 network are of the highest importance for conservation in Europe. However, they often occur in smaller areas and their conservation status is not well understood. One such HT is that of the Tilio–Acerion forests of slopes, screes and ravines (9180*). The Natura 2000 study site, Boč–Haloze–Donačka gora, in the Sub-Pannonian region of eastern Slovenia is characterized by a matrix of European beech forests and includes rather small, fragmented areas covered by Tilio–Acerion forests. The goal of this research was to examine the heterogeneity and conservation status of the selected HT through field mapping, which was performed in the summer of 2020. As the conservation of HT calls for a more detailed approach, we distinguished between the following four pre-defined habitat subtypes: (i) Acer pseudoplatanus-Ulmus glabra stands growing mostly in concave terrain, (ii) Fraxinus excelsior stands growing on slopes, (iii) Tilia sp. stands with thermophilous broadleaves occurring on ridges and slopes, (iv) Acer pseudoplatanus stands occurring on more acidic soils with an admixture of Castanea sativa. Field mapping information was complemented with the assessment of habitat subtype characteristics using remote sensing data. The results showed that habitat subtypes differed significantly in terms of area, tree species composition, forest stand characteristics, relief features and the various threats they experienced (e.g., fragmentation, tree mortality, ungulate browsing pressure). The differences between subtypes were also evident for LiDAR-derived environmental factors related to topography (i.e., terrain steepness and Topographic Position Index). This study provides a baseline for setting more realistic objectives for the conservation management of priority forest HTs. Due to the specificities of each individual habitat subtype, conservation activities should be targeted to the Natura 2000 habitat subtype level.

The Soil Seed Bank Role in Mountainous Heathland Ecosystems after Fire and Inorganic Nitrogen Fertilization

Calluna vulgaris-dominated heathlands are a priority habitat type in Annex I of the Habitats Directive (92/43/ECC, habitat code 4060). In the Iberian Peninsula, the landscape of the Cantabrian Mountain range has great heterogeneity due to human management during the last 10,000 years. Another factor that can affect these communities is the increase in human-induced atmospheric nitrogen (N) deposition. During the last century, there has been a dramatic increase in N deposition rates. For all these reasons, it is important to know the regeneration dynamics of the heathlands in the context of the disturbances that these communities currently face (i.e., N deposition, fire, and decrease in sheep grazing) in the Cantabrian Mountain range. In this study, we characterized the plant species composition and soil seed bank after prescribed burning in three heathlands on their southern distribution limit in Spain, to gain insights into regenerative capacity and conservation of these communities. The results obtained suggest that the post-burn soil seed bank could restore Calluna-dominated vegetation in these habitats, indicating that the restoration potential from the soil seed bank after wildfires of these habitats is high. Our results also suggest that, in the short term after burning, the main characteristic species such as Calluna and Erica are recovered, which is fundamental to maintain the heathland community structure.

Investigation of Flood Management and Mitigation Measures in Ungauged NATURA Protected Watersheds

The aim of this study is to investigate the flood management and mitigation measures in ungauged NATURA protected watersheds. The examined watersheds are located in one the most European significant NATURA areas (Prespa Natural Park North Greece). SCS-CN model was applied to perform the hydrological modeling for extreme rainfalls of 50, 100 and 1000 return periods. Extensive field research was conducted to record all the hydrotechnical works of the study area, to evaluate their current condition and measure the respective hydraulic characteristics. The results of the hydrological modeling showed that the flood danger in the study area is generally low. However, almost the half of the hydrotechnical works could not discharge the high and medium probability (50 and 100 years) peak flows. The main causes are the extremely dense riparian vegetation that has been developed on the banks and the thalweg of the riverbeds and in some cases the inappropriate dimensioning of the technical works. The intense development of the riparian vegetation, has increased the roughness coefficient and reduced the dimensions and discharge capability of the technical works, while NATURA restrictions and regulations may be limiting any logging and trimming activities within the streams, especially in priority habitat types. Special Ecological Evaluation studies and educating the public about the necessity of the flood control measures and impact, could provide a framework for a thorough discussion about the flood management in NATURA areas.

Riparian Vegetation Along the Scroafa Stream and Its Tributaries (Southern Transylvanian Tableland) Under Changing Ecological Conditions and Human Intervention

Abstract The riparian softwood galleries of the Scroafa Stream basin, part of the South Eastern Transylvanian Tableland are presented and discussed under the aspect of their site conditions, species composition, vertical structure by different layers, ecological requirements and their change along the stream banks from the source to the mouth in the Târnava Mare River. Their stretches are compared, with commonalities and differences highlighted. The impact of human dependent changes and the future of the galleries with climate changes are addressed. The importance of the riparian softwood stands is also presented in the context of the Natura 2000 network, as they are included in the list as priority habitat types.

Assessment of the Geo-Environmental Status of European Union Priority Habitat Type “Mediterranean Temporary Ponds” in Mt. Oiti, Greece

Mediterranean Temporary Ponds (MTPs) constitute priority habitat under the European Union Habitats’ Directive. They are inhabited by rare species and subjected to unstable environmental conditions. Lakes and ponds act as early indicators of climate change, to which high altitude ecosystems are especially vulnerable. This study presents a full dataset of the geo-environmental parameters of such habitats (MTPs) along with their current ecological status for the first time. Furthermore, this paper aims to address the lack of basic geo-environmental background on the network of MTPs of Mt. Oiti concerning their geological, geomorphological, mineralogical and geochemical characteristics along with the pressures received from various activities. The study area is located in a mountainous Natura 2000 site of Central Greece, which hosts four MTPs. Fieldwork and sampling of water and bottom sediments were carried out during dry and wet periods between 2012 and 2014. Electrical Resistivity Tomography measurements identified synforms shaped under the ponds that topography does not always adopt them, mostly due to erosion procedures. The most significant feature, distinguishing those pond waters from any other province water bodies is the extremely low content of all studied ions (including NO2−, NO3−, NH4+, PO43−, HCO3−, SO42−, Al, As, B, Ba, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Fe, Ga, Gd, Ge, Hf, Hg, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Rb, S, Sb, Se, Si, Sn, Sr, Ti, U, V, W, Zn, and Zr). MTPs water bodies are of bicarbonate dominant type, and a fresh meteoric water origin is suggested. The main pressures identified were grazing and trampling by vehicles. MTPs of Mt. Oiti were classified according to their ecological status form excellent to medium. Our results can contribute to a better understanding of the mountainous temporary ponds development in the Mediterranean environment.

Natura 2000 priority and non-priority habitats do not differ in soil nematode diversity

Extensive biodiversity conservation efforts in Europe resulted in the recent establishment of the ecological network of protected areas Natura 2000. However, it remains unclear how such protected areas reflect the distribution of soil biodiversity, which represents a substantial fraction of terrestrial biodiversity and drives a plethora of ecosystem services. Here we analyzed and compared different metrics of soil nematode taxonomic diversity, i.e., taxon richness, Shannon Diversity Index, Shannon Evenness (all based on supraspecific diversity), and functional diversity, i.e., Maturity Index (environmental disturbance), Structure Index (food web complexity), Enrichment Index (system enrichment), and Channel Index (dominant decomposition pathway of soil organic matter) in 16 grasslands assigned to two Natura 2000 priority habitat types and 14 grasslands assigned to five Natura 2000 non-priority habitat types in Romania. Nematode communities consisted of a total of 123 taxa (115 genera and 8 suprageneric taxa). We found no significant difference in nematode taxonomic and functional diversity between grasslands assigned to Natura 2000 priority and non-priority habitats, suggesting that this categorization does not reflect nematode diversity patterns.

Vegetation units of wetland and terrestrial habitats: the case study of Spercheios River and Maliakos Gulf (Sterea Ellas, Greece), a Natura 2000 Site

AbstractThe vegetation of the European Natura 2000 protected area of Spercheios river and Maliakos gulf, that includes Mediterranean sclerophyllous shrublands, as well as riverine and coastal habitats, was studied during 2000 and 2014–2015. The vegetation was analysed following the Braun-Blanquet method. Twenty six plant communities were recorded, one of which (Pistacio terebinthi-Quercetum cocciferae) described for the first time. The communities belong to fifteen alliances, fourteen orders and eleven phytosociological classes. The distinguished vegetation units are described, presented in phytosociological tables and compared with similar communities from other Mediterranean countries. Eleven different habitat types were identified. Two of them (“Quercus cocciferawoods” and “Reed beds”) are Greek habitat types, while the rest are included in Annex I of the Directive 92/43/EEC. Three of the latter (1420, 2110, 3170) have a scattered presence in the Natura 2000 network in Greece, while one (3170) is a priority habitat type.

Evaluating an unmanned aerial vehicle‐based approach for assessing habitat extent and condition in fine‐scale early successional mountain mosaics

AbstractQuestionCan very high‐resolution colour orthophotography and digital surface models (DSMs) from an unmanned aerial vehicle (UAV) be effectively used for assessment of habitat extent and condition in fine‐scale disturbance‐dependent mosaics?LocationSerra de Arga mountain range, a Natura 2000 protected site in the NW region of Portugal where drastic changes in pastoral activities have occurred over recent decades.MethodsAn UAV platform was used to collect very high‐resolution (6 cm) images and to produce a DSM (10 cm). From these data, several features were extracted related to colour, band ratios, as well as texture features calculated from colour imagery and surface elevation. Based on a systematic sampling design, field data were collected for both training and validation of a supervised classifier. Extracted features and ground truth training data were combined to calibrate a pixel‐based Random forest classifier, with the purpose of devising a habitat map for the entire study area. Map validation was performed to assess classification accuracy, and feature importance metrics were calculated.ResultsValidation results revealed good mean overall accuracy (0.89), with some performance decrease in situations of high interspersion of habitat types. The priority habitat type 6230* (Nardus grasslands), defining the vegetation matrix of the test site, obtained 0.96 and 0.91, considering, respectively, producer and user accuracy. In turn, priority habitat type 4020* (Atlantic wet heathlands) recorded 0.68 and 0.77. The obtained habitat map allowed measurement of the extent, description of the spatial arrangement and provided an indication of the conservation condition of target habitat types. Test results regarding the discrimination ability of different features highlighted the importance of surface elevation textures derived from the DSM, followed by band ratios textures and other more complex texture features calculated from colour imagery.ConclusionsOverall, the developed methodology showed promising results for assessing the extent and condition of habitats of high conservation priority in fine‐scale, dynamic vegetation mosaics. Future advances in the use of UAV platforms may play an important role in monitoring protected sites and fulfil legal reporting obligations of EU member states, while reducing the costs associated with intensive in‐field assessments.

Prioritizing Odonata for conservation action in the northeastern USA

Odonata are valuable biological indicators of freshwater ecosystem integrity and climate change, and the northeastern USA (Virginia to Maine) is a hotspot of odonate diversity and a region of historical and grow- ing threats to freshwater ecosystems. This duality highlights the urgency of developing a comprehensive conser- vation assessment of the region's 228 resident odonate species. We offer a prioritization framework modified from NatureServe's method for assessing conservation status ranks by assigning a single regional vulnerability metric (R-rank) reflecting each species' degree of relative extinction risk in the northeastern USA. We calculated the R-rank based on 3 rarity factors (range extent, area of occupancy, and habitat specificity), 1 threat factor (vulnerability of occupied habitats), and 1 trend factor (relative change in range size). We combine this R-rank with the degree of endemicity (% of the species' USA and Canadian range that falls within the region) as a proxy for regional responsibility, thereby deriving a list of species of combined vulnerability and regional management responsibility. Overall, 18% of the region's odonate fauna is imperiled (R1 and R2), and peatlands, low-gradient streams and seeps, high-gradient headwaters, and larger rivers that harbor a disproportionate number of these species should be considered as priority habitat types for conservation. We anticipate that our analysis might serve as a model for guiding and standardizing conservation assessments at multiple scales for Odonata and other diverse taxa that have not yet received attention to prioritization.

Dry Grassland Types in the Prespa National Park (Nw Greece), Including the Southernmost Occurrence of the Priority Habitat Type “Pannonic Sand Steppes” (Code 6260)

Abstract A recently completed project on the Natura 2000 sites of Prespa National Park revealed that the area hosts 49 habitat types according to the EU classification, of which eight have a narrowly restricted distribution in Greece. The priority habitat type “*6260 Pannonic sand steppes” is reported here for the first time for Greece. The new locality represents its southernmost occurrence on the Balkan Peninsula. The aim of this paper therefore is to describe the Greek stands of this habitat type, investigate the factors affecting its occurrence and discuss the associated conservation issues. This is based on a total of 87 releves sampled for this study and 8 additional releves from the literature. The releves were classified by applying TWINSPAN and ordinated using Detrended Correspondence Analysis (DCA). Six vegetation units could be distinguished. One of these corresponds to the habitat type *6260 and was found exclusively on inland sand dunes. Syntaxonomically, we assigned this unit to the alliance Sileno conicae-Cerastion semidecandri s.l. of the class Koelerio-Corynephoretea. Its occurrence in the study area seems to be determined by climatic factors, as well as by the sandy substrate, while anthropogenic disturbances such as grazing also appear to be beneficial to some degree. Apart from the Koelerio-Corynephoretea, another five grassland classes were distinguished in the national park, namely the Thero-Brachypodietea, Stellarietea mediae, Festuco-Brometea, Daphno-Festucetea and Juncetea trifidi.

Integrating environmental policies towards a network of protected and quiet areas

SummaryEnvironmental policy integration is an acknowledged principle of sustainable development. Spatial planning may be a useful means of integrating two policies with differing objectives. The Birds and Habitats Directives of the European Union (EU) aim at preserving biodiversity through the conservation of the Natura 2000 protected areas network, while the EU's Environmental Noise Directive aims at improving human health and wellbeing by controlling environmental noise, through the preservation of Quiet Areas (QAs). Using Greece as an example, an integrated network of Natura 2000 sites and QAs permitted the identification of potential spatial overlaps. The established Natura 2000 network incorporates more than 30% of the QAs located in the open countryside of Greece, and the combined network includes 17 out of the 19 conservation priority habitat types. Flagship species (like bear, wolf and wild goat) show a preference for sites containing QAs. It may be possible to combine these two EU policies efficiently, as protected and quiet areas appear to be mutually beneficial.

Diversity and distribution of spiders (Arachnida: Araneae) in dry ecosystems of North Rhine-Westphalia (Germany)

The present study provides a robust data set for ecological planning and conservation of dry ecosys- tems in western Germany in general and North Rhine-Westphalia in particular. We summarised all available data from recent publications that dealt with spiders in dry ecosystems of North Rhine-Westphalia. Additionally, so far unpublished results of a detailed investigation regarding spiders in sand habitats of the Westphalian Bay that was conducted between 2006 and 2008 are presented. The analysis focussed on the habitat types according to Annex I of the EU Habitats Directive and related habitats. The investigation areas were scattered in the federal state of North Rhine-Westphalia. The data set comprised a total of 84436 individuals from 371 species and 28 families. Overall, an endangerment status is assigned to 68 species. Of these, 12 spiders are in imminent danger of becoming extinct. Two species, Erigonoplus globipes and Meioneta simplicitarsis, are believed to be extinct in North Rhine-Westphalia. Seven species (Dictyna major, Mastigusa arietina, Micaria formicaria, Styloctetor romanus, Thanatus striatus, Theridion uhligi and Xysticus ferrugineus) are new to the arachnofauna of North Rhine-Westphalia. In Germany, dry ecosystems, such as nutrient-poor sandy grasslands, dry heaths and semi-natural dry grasslands and scrubland facies on calcareous substra- tes are highly endangered (RIECKEN et al. 2006) and are listed in Annex I of the European Habitats Direc- tive as priority habitat types (BALZER & SSYMANK 2005). Due to increasing cultivation, especially during the past 50 years, and the lack of disturbance (drif- ting sand, grazing, fire) the area of dry ecosystems has decreased considerably in northern and western Germany (DRACHENFELS 1996, VERBUCHELN & JOBGES 2000, JENTSCH et al. 2002, KRATOCHWIL

Natura 2000 Habitat Types of Greece Evaluated in the Light of Distribution, threat and Responsibility

Natura 2000 Habitat Types of Greece Evaluated in the Light of Distribution, threat and Responsibility

Loss of palsa mires in Europe and biological consequences

Palsa mires are northern mire complexes with permanently frozen peat hummocks. These are degrading throughout their distribution range, probably because of regional climatic warming. This review of the current understanding of the geographical, climatic and biological characteristics of palsa mires focuses on Europe. Recent studies have reported a drastic decrease in the extent of palsa mires in Fennoscandia; in Finland, the distribution of palsas was formerly about three times that at present. With continued or accelerated warming, as predicted for high latitudes, further extensive degradation or the wholesale disappearance of palsa mires seems inevitable. Palsa mires are known to be biologically heterogeneous environments with a rich diversity of bird species, and they are listed as a priority habitat type by the European Union. However, their role as habitats for other organisms is still poorly understood. There is urgent need for research and monitoring to assess the ecological and biological consequences of the decline of palsa mires in Europe.

Ecology, management and monitoring of grey dunes in Flanders

Grey dunes are a priority habitat type of the European Union Habitats Directive and demand special attention for conservation and management. Knowledge of the ecology of coastal grey dunes can contribute to this policy. Dune grassland succession is initiated by fixation and driven by the complex of soil formation (humus accumulation) and vegetation development. Leaching and mobilization of CaCO3. which are important in nutrient dynamics, complicate the picture. At present, grass- and scrub encroachment greatly overrules these fine scaled soil processes and causes substantial loss of regional biodiversity. Belgium has an international responsibility in grey dune conservation because of the limited range of its characteristic vegetation, flora and fauna. As biomass removal seems essential in grassland preservation, grazing is an important management tool. Evaluation of management measures focuses on biodiversity measurements on the levels of landscape, community and species.

Effect of track spacing and data interpolation on the interpretation of benthic community distributions derived from RoxAnn™ acoustic surveys

Abstract A 150 mile2 (388 km2) area in the South Minch on the Scottish west coast was surveyed acoustically using the seabed discrimination system RoxAnn™. This site was chosen from BGS seabed sediment maps because of the wide variety of substratum types present within a relatively small area. The work presented here investigates different combinations of survey track spacing in relation to interpolation of acoustic data for mapping benthic biodiversity. Three different survey track spacings (4, 2 and 1 km) and three pixel sizes (1000, 500 and 250 m) were utilised. The results indicated considerable variations in the fine scale variations of the substratum maps produced and their accuracy in relation to ground truth data. Depending on the track spacing and level of interpolation utilised, the survey site could be considered relatively important under the UK Biodiversity Action Plan in terms of priority habitat types present or completely insignificant. These variations have serious implications for the use of this technology in site identification, conservation and management.