Favourable Conservation Status Research Articles

Transdisciplinary approach to the characterisation and current status of Spanish karstic lakes on gypsum

Karstic lakes on gypsum are a very peculiar type of ecosystem declared as a Habitat Type of Community Interest (Type 3190) by the European Habitats Directive. They are usually small lakes but often displaying a high relative depth, located in active gypsum karst areas, with a high saturation of Ca2+ and SO42− in its waters. These lakes can usually stratify from spring to early autumn when the depth is high enough, then a sulphide-rich anoxic hypolimnion can develop in deep layers. So far, neither a comprehensive scientific definition of their ecological characteristics nor an exhaustive catalogue of their occurrence in a particular territory are available. This paper delves on their biotic and abiotic features needed for their identification as an ecosystem type. A proper methodology was also designed and applied for the evaluation of their conservation status, with the definition of reference values and assessment methods following the criteria of the Habitats Directive. The Spanish karstic lakes on gypsum (THCI 3190) were here identified, statistically representative sites were selected, and spatial GIS methods and multimetric indices were applied to assess the range, area, structure and function, and future prospects of this Habitat Type, as requested for the reporting according to Article 17 of the Habitats Directive. Results showed a favourable conservation status of this habitat type in the Alpine and Atlantic regions of Spain, but unfavourable-inadequate status in the Mediterranean, due to the pressures and impacts acting on some specific sites. A critical analysis of the methodologies and the values obtained for its conservation status was carried out.

Měkkýši přírodních památek V Krátkých a Lom Rasová v CHKO Bílé Karpaty [Molluscs of the V Krátkých and Lom Rasová Nature Monuments in the White Carpathians PLA

The V Krátkých Nature Monument (NM) comprises of landscape mosaic of meadows, groves, spring fen and wetland while the Lom Rasová NM is a former sandstone quarry with open and forested areas. Both are situated near Vápenice village in the White Carpathians. In total, 44 species (40 terrestrial gastropods, 3 aquatic snails and 1 bivalve) were found in V Krátkých NM. Three species are listed in the Red List of Threatened Species: Daudebardia brevipes (VU), Lehmannia carpatica (NT) and Bythinella austriaca (NT). Most diversity consists of forest species, followed by eurytopic and hygrophilous species. The spring fen is the most species-rich habitat, as hygrophilous, eurytopic and forest species are present. To retain the favourable conservation status, extensive kettle grazing or mowing of the fen and meadows is suggested while the groves should remain in a non-intervention regime with possible subtle intrusion of broadleaved trees. In the Lom Rasová NM, 18 terrestrial gastropod species were recorded (aquatic malacofauna was not surveyed). All species are common and widespread, and their composition is a mixture of predominantly forest, euryvalent and open-country taxa. To support gastropod diversity, the broadleaved groves should remain in a non-intervention regime, while deciduous trees should be replaced with broadleaved species and overall habitat diversity should be supported.

Reintroduction of large carnivores in Europe: a case study on frictions between rules of law and rules of nature

Scientists have announced the Anthropocene as a geological epoch in which human impacts have become dominant, and the human/nature dichotomy seems to have been transcended. This article examines if, and under what conditions, the obligation to maintain or restore natural habitats and species of wild fauna at favourable conservation status under EU Nature protection law (Habitats Directive) includes obligations for EU member states to reintroduce species against the dynamic backdrop of the Anthropocene. The dynamics of the Anthropocene pertain to time (past or historical versus present or current presence of a species within a particular habitat), space (native or indigenous ecosystem versus human-induced or anthropogenically changed ecosystem or habitat) and ontologies (‘natural’ versus ‘human’ reintroduction). Focusing on the particular issue of the ‘restoration’ and ‘reintroduction’ of populations of large carnivores – so-called keystone species – in the EU, these temporal, spatial and conceptual dimensions (nature/human dichotomy) of the Habitats Directive are explored in the context of three concrete reintroduction scenarios. Considering this setting, what have the obligations to maintain and to restore come to imply, and is a disconnect emerging between the relatively static ‘rules of law’ and dynamic ‘rules of nature’?

Cattle population required for favorable conservation status of management-dependent semi-natural grasslands and forests, and associated increase in enteric methane emissions

The state of biodiversity in the world is critical where natural grassland is one of the habitat types showing the strongest deteriorating trend of biodiversity loss. At European Union level, 75 % of all grassland habitats have poor or bad status, with cessation of farming and subsequent overgrowth posing the greatest threat. To achieve favorable conservation status of natural grasslands, the area given over to grazing livestock or hay mowing needs to increase in many regions. The aim of this study was to calculate the number of cattle required to manage various types of unfertilized grazing land, and associated enteric methane emissions from these cattle, using Sweden as the study area. Four different scenarios with various categories of grazing cattle were evaluated: beef suckler cows and their offspring or dairy and beef cows in the current ratio and their offspring, combined with all male calves being raised as grazing steers or with males being raised as grazing steers in the current ratio and other males being raised as indoor bulls. Potential important factors that could reduce the number of additional cattle required were considered. The scenario requiring the smallest number of animals, beef cows and their grazing offspring, gave the lowest methane emissions, 16 kg/ha/year for low-yielding grazing land, such as wooded pasture, and 117 kg/ha/year for high-yielding grazing land, such as wet meadows. Taking all cattle reducing factors into account (mowing parts of the area, lower predicted stocking rate, use of all existing male cattle) significantly reduced the required cattle stock to one-third, corresponding to methane emissions of 5 and 34 kg/ha/year for low and high-yielding grazing land, respectively. In Sweden, 2.2 million ha of grazing land need to be restored to favorable conservation status, which would require 150 000–510 000 new beef cows and their grazing offspring would be needed, producing 33 000 to 109 000 tonnes of methane, compared to the 105 000 tonnes emitted by the present cattle stock (around 300 000 dairy cows and 210 000 beef cows).

Applying genomic approaches to identify historic population declines in European forest bats

Abstract Anthropogenically driven environmental changes over recent centuries have led to severe declines of wildlife populations. Better tools are needed to assess the magnitude and consequences of these declines. Anecdotal evidence suggests European bat populations have suffered substantial declines in the past centuries. However, there is little empirical evidence of these declines that can be used to put more recent population trends into historic context. This study is a collaboration between academics and conservation practitioners to develop molecular approaches capable of providing evidence of historic population changes that can inform conservation status assessments and management. We generated a genomic dataset of 46,872 SNPs for the Western barbastelle, Barbastella barbastellus, a regionally Vulnerable bat species, including colonies from across the species' British and Iberian ranges. We used a combination of landscape genetics and model‐based inference of demographic history to identify both evidence of population size changes and possible drivers of these changes. Levels of genetic diversity increased and inbreeding decreased with increasing broadleaf woodland cover around the colony. Genetic connectivity was impeded by artificial lights and facilitated by rivers and broadleaf woodland cover. The demographic history analysis showed that both the northern and southern British barbastelle populations have declined by 99% over the past 330–548 years. These declines may be linked to the loss of large oak trees and native woodlands due to shipbuilding during the early colonial period. Synthesis and applications. Genomic approaches can provide a better understanding of the conservation status of threatened species, within historic and contemporary contexts, and inform their conservation management. Our findings of will directly influence the definition of the Favourable Conservation Status of the barbastelle, in turn influencing considerations of the conservation of the species in development plans. Knowledge gained will also help set species recovery targets. Policymakers are interested in using our approach for other species. This study shows how we can bridge the implementation gap between genomic research and direct conservation applications. There is an urgent need to carry out such collaborative studies for other priority species to enable informed species recovery interventions via policy mechanisms and project delivery.

Extending the interpretation of Natura 2000 habitat types beyond their definition can bias their conservation status assessment: An example with species-rich Nardus grasslands (6230*)

In this study, taking as an example the species-rich Nardus stricta grasslands (habitat 6230*) within the Natura 2000 network of the Lombardy region (northern Italy, central southern Alps), we evaluated i) whether the spatial distribution of the habitat 6230* corresponded to essential features for its identification, and ii) whether a broad habitat interpretation could affect its regional conservation status assessment.We analysed the spatial distribution of habitat 6230* regarding the elevation, geological substrate, forest treeline, land use types and other habitat types. Using the regional database of habitat relevés, we calculated the threshold values of conservation status for a range of indicators of structure, functions and future prospects. To this end, we used a subset of relevés of the subalpine sub-type of habitat 6230*, as it corresponds to plant communities where habitat interpretation can easily be extended beyond its definition.The mapped distribution of habitat 6230* did not entirely match the essential features required for its identification. Some polygons were located at the ecological extremes of habitat 6230*, on carbonate substrates and in the alpine belt. In those conditions, the habitat showed an Unfavourable-bad (U2) conservation status, decreasing species richness and typical species dominance and frequency. Our findings highlighted that plant communities representing ecological extremes of the habitat type 6230* should no longer be referred to the same habitat type.The proposed indicators can help identify habitat sub-types more conducive to successful restoration measures, thereby ensuring favourable conservation status. In turn, this guarantees sustainable agricultural land use, which simultaneously promotes biodiversity and high-quality food products. Furthermore, the procedure could be extended to other habitat types for early identification of priority monitoring areas, especially when their interpretation has gone beyond their definition, with little consideration given to the consequences on the regional conservation status assessments.

Fit by design: Developing seed–substrate combinations to adapt dike grasslands to microclimatic variation

Abstract Sowing is a well‐established restoration technique to overcome dispersal limitation. Seed mixtures adapted to certain environmental conditions, like substrate or microclimate, are most effective to achieve functional communities. This is especially important if the restored vegetation has to protect critical infrastructure like roadsides and dikes. Here, an improved seed–substrate combination will secure slope stability, make restorations more effective and generate species‐rich grasslands. A full‐factorial field experiment addressed this topic on a dike at River Danube in SE Germany in 2018–2021. Within 288 plots, we tested three sand admixtures, two substrate depths, two seed densities and two seed mixture types (mesic hay meadow and semidry calcareous grassland) in north and south exposition and measured the recovery completeness by calculating the successional distance to reference sites, the persistence of sown species and the Favourable Conservation Status (FCS) of target species. Overall, the sown vegetation developed in the desired direction, but a recovery debt remained after 4 years, and some plots still showed similarities to negative references from ruderal sites. In north exposition, hay meadow seed mixtures developed closer to their reference communities than dry grassland mixtures to their reference. In south exposition, the sown communities established poorly, which might be due to a severe drought during establishment. This initial negative effect remained over the entire observation period. Sand admixture had a slightly positive effect on target variables, while the tested substrate depths, seed densities and seed mixture types had no effects on species persistence or FCS. Synthesis and applications: Site‐adapted seed mixtures make restoration more effective, while applying several seed–substrate combinations might foster beta diversity. Furthermore, additional management efforts are recommended, as they might be necessary to reduce the recovery debt, as well as re‐sowing after unfavourable conditions like droughts.

Romanogobio Banaticus (Bănărescu, 1960) in the Nera River (Danube Basin)

Abstract Romanogobio banaticus it is a species of conservation interest with a small distribution range in the south-west of the Romanian Carpathians basin. In spite of the presence of some moderate anthropogenic threats and risks, the Nera River is a sanctuary for this fish. The lower latitude of Nera in comparison with other rivers where this fish is living, explain its presence in an atypical ichthyological zone. This species presence is permanent, the abundance is relatively high, the age structure is well balanced, more than that, in some sectors is a co-dominant species, all of these revealing a favourable conservation status.

Limiting scaring activities reduces economic costs associated with foraging barnacle geese: Results from an individual‐based model

Abstract With increasing numbers of large grazing birds on agricultural grassland, conflict with farmers is rising. One management approach to alleviate conflict allows foraging on dedicated agricultural land (accommodation areas) and nature reserves, combined with scaring on remaining agricultural land. Here, we examine the cost‐effectiveness of these measures by studying the influence on barnacle goose distribution and associated economic damage. We present an individual/agent‐based model of barnacle geese (Branta leucopsis) foraging on grasslands in Friesland, the Netherlands. The model is parameterized using field observations and GPS‐tracks and allows simulation of management scenarios, differing in scaring probability and accommodation area size, with different potential management costs. Our model shows that, while yield loss decreases with higher scaring probabilities, costs of damage appraisal increase because geese graze on more fields. With small accommodation areas, achieving high scaring probabilities takes more effort and could result in goose population decline. Total management costs are lowest without scaring activity. Synthesis and applications. Considering costs of active scaring and the need to maintain the barnacle goose population in a favourable conservation status, our model suggests that the most cost‐effective scenario is to prevent disturbance of geese. A high scaring probability could be beneficial if applied in small areas, for example around sensitive crops or airfields. Scaring in large areas could result in costs outweighing benefits and a declining barnacle goose population.

Development of indicators for assessment of green infrastructure for a territorial network of ecological stability

Landscape structure and biotic indicators have a significant role in assessing the green infrastructure of a landscape and design of a territorial ecological network. In this contribution, a methodological approach has been developed for assessing and defining indicators of current land use and biota that can be used for designing a territorial network of ecological stability. We used the assessment of ecological stability of the elements of the current landscape structure, an index of the ecological stability of a representative geo-ecosystem, the cumulative effect of high ecological stability landscape elements, and the Shannon Diversity Index (SHDI) to measure the degree of entropy, or landscape diversity. The assessment of biota was based on qualitative habitat field data and an evaluation of their overall nature conservation importance based on the type of land cover and habitats, the importance of habitats, their current conservation status, how many rare habitats are in a region, and how many vulnerable species are present in habitats. The assessment was applied on a local level, using the example of the Dolný Lopašov study area. The spatial distribution of green infrastructure is not balanced within the study area. The most significant elements of the ecological network consist of natural and semi-natural habitats that have a favourable conservation status. The Malé Karpaty Mountains, situated in the northern region, are forest-covered and have the highest ecological stability. Intensively cultivated fields are dominant in the central and southern parts of the study areas and are characterised by a low proportion of green infrastructure and low ecological stability. The results of the modelling of the cumulative impact of landscape elements on ecological stability by distance show that the cumulative impact of woodland elements positively affects the ecological stability of the area, especially in the area of intensively cultivated fields, an element with a low degree of ecological stability. Using selected indicators of current landscape structure and biota helps to assess the overall ecological stability of the area, identify the most stable areas, as well as areas with the lowest ecological stability, where it is necessary to complete and design new elements of green infrastructure to increase the function of the ecological network.

Natura 2000 A Panacea? Natura 2000 Site Oltul Mijlociucibin-Hârtibaciu (ROSCI0132) ‒ a Local Extinction of a Native Fish Species and a New Alien Fish Arrival Case Study

Abstract The Romanian Oltul Mijlociu-Cibin-Hârtibaciu Natura 2000 site of community importance (SCI) was designated for the purpose of protecting biodiversity and maintaining the wild flora and fauna in a favourable conservation status, as well as the natural habitats of conservation interest. This research focused on the possible disparition of one protected fish species Pelecus cultratus (Linnaeus, 1758) and the appearance of an alien one Babka gymnotrachelus (Kessler, 1857), as ecological indicators of the fact that at least this Natura 2000 site is far from being properly protected and a new, more responsible way should be followed and different administrators put in charge of the areas management.

Forest management plans as data source for the assessment of the conservation status of European Union habitat types

Natura 2000 is a European network of protected sites that should enable natural habitats to be maintained or restored at a favorable conservation status. Progress toward this objective must be periodically reported by states members of the European Union. We investigated how forest management plans might provide data to support the reporting. The study was done in the forests of the Dolomites and Venetian Prealps, Italy. Here, about 200 forest management plans, divided into several forest compartments, have been drawn up and revised every 10–15 years. Stand structure variables were retrieved from past (OR, 1970–1980) and more recent revisions (NR, 2000–2010) of 331 forest compartments ranging between 0.35 and 53.1 ha. In the beech and spruce forest habitat types (coded 9130 and 9410 in Annex I of the Directive 92/43/EEC, respectively), we found an increase from OR to NR in the density of large trees (from 32 to 46/ha and from 31 to 50/ha, respectively for the two habitats), basal area (from 27.3 to 31.5 m2/ha and from 31 to 34.5 m2/ha), mean diameter (from 34.1 to 36.2 cm and from 33.9 to 36 cm) and Gini index (from 0.35 to 0.37 and from 0.33 to 0.36). Pursuant to the Directive 92/43/EEC, the conservation status of these two habitat types should be taken as “favorable” with regards to the criterion related to the habitats’ specific structure and functions that are necessary for its long-term maintenance. We conclude that forest management plans provide a great portion of the information needed for assessing and monitoring the conservation status of forest habitat types in the Natura 2000 framework.

Shifting baselines for species in chronic decline and assessment of conservation status. Are hazel dormiceMuscardinus avellanariusEndangered?

AbstractLong‐term data are beneficial for monitoring the conservation status of species. Assessments of population change over recent periods of fixed duration will, however, be subject to ‘shifting baselines’, where the accepted norm for the population at the start of the period already represents a reduction from historical levels. International Union for Conservation of Nature Red List criteria for categorizing conservation threat rely on assessing declines against quantitative thresholds, generally measured over 10 years, as indications of the likelihood of extinction in the near future. By contrast, legal frameworks such as the European Habitats Directive require states to achieve and sustain ‘Favourable Conservation Status’ for protected species, while domestic conservation legislation can have more diverse objectives and mechanisms, based on local contexts that extend beyond biological or quantitative criteria.We explore the challenges associated with assessing the risk of extinction and the conservation status that arise from the availability of long‐term monitoring data for hazel dormiceMuscardinus avellanariusin the United Kingdom.Numbers of adult dormice counted in the National Dormouse Monitoring Programme are in ongoing decline, amounting to an overall decline of 78% (95% confidence interval = 72%–84%) over 27 years, 1994–2020. If the observed annual rate of decline of 5.7% (95% CI = 4.7%–6.8%) were to continue unabated, dormouse counts would decline by >90% from 1994 to 2034. Despite this, the species would never be categorized as Endangered, under IUCN criteria, which specify a reduction of >50% within 10 years.While such chronic decline may not indicate imminent risk of extinction, justifying a higher Red List category, it is a demonstration of unfavourable conservation status at a national scale. Prioritization based on demonstration of such chronic declines might direct more effective action towards species conservation at a point when their recovery is more attainable, rather than attempting later to reverse a journey to the brink of extinction when the species is finally ‘Endangered’.

Hosszú távú kaszálás hatása a vegetációra és a biomassza összetételére a Nyugat-Cserhát pannon száraz gyepeiben

This study is focusing on the vegetation of seminatural dry grasslands. Those loess grasslands are valuable with large biodiversity; however their long-term preservation requires regular conservation management. The report demonstrates the results of mowing experiment, designed to suppress the spread of unpalatable grass species, Calamagrostis epigeios. The study site is located in mid-successional loss grasslands, in the Western-Cserhát, near Rád, northern Hungary.
 The study aims to the investigate the followings: Can the unpalatable Calamagrostis epigejos be suppressed by mowing? Are there possibilities to increase the diversity of sward by this? The study aims, to measure potential value-increasing effect of mowing, and to determine the carrying capacity in the aspect of grassland management.
 In 2001, Camagrostis epigeios was the species with the highest coverage rate according to the both treatment types, with an average cover value of 63%. However, as a result of mowing, a significant difference was detected in the amount of litter and legumes species as well. The number of species showed a slight increase in both types of treatment, from 15 to 37 in the mowed plots, but also from 18 to 27 in the control plots. We concluded that mowing twice a year was beneficial to modify botanical composition of a grassland. In a way it was suited well for agricultural usage, in particular grazing which can replace the expensive and time-consuming scythe. It is also a suitable management measure for controlling the native invader species as a Calamagrostis epigeios, and can significantly increase the proportion of species with higher forage values.
 Mowing has significantly increased the density of Calamagrostis epigeios, the species richness, and the diversity in the course of secondary succession. Therefore, mowing twice a year proved to be a successful management measure for controlling Calamagrostis epigeios, and for obtaining a sward composition. The treatment was effective in restoring grassland composition, although the achievement and maintenance of favourable conservation status for the grassland habitat require long-term management planning and regular treatment. According to the objectives, mowing not only promotes the control of the invasive species, but also the economic utilization of the area.

A strategic evaluation framework to measure and guide efforts to protect biodiversity

Through the Natura 2000 policy, EU member states are committed to maintaining or restoring the favourable conservation status of a list of habitats and species throughout their territory. We show here that evaluating the effectiveness of this policy regarding its assigned objectives requires translating these objectives into normative reference and then describing the constraints on habitats and species that the policy seeks to conserve. We propose a strategic evaluation framework based on this principle, applied at the level of the Metropolitan French territory, by relying on the exploitation of several data sets, whose are generally not mobilised by the standard evaluation procedure. The results are broken down by natural ecosystems and biogeographical regions, providing a dashboard for the policy that is the basis for a comprehensive strategic evaluation.

Bottlenose dolphins share fish farm areas while maintaining sexual segregation: Investigating group memberships through spatially and temporally explicit parameters

Abstract Group membership is a key attribute of animal societies and central to the study of social structure in several taxa. However, social structure analyses are sensitive to the way data are collected and associations defined. In this study, a time–space method was used to investigate the social structure of common bottlenose dolphins Tursiops truncatus observed and photographed across 7 years in the semi‐enclosed Gulf of Corinth, Greece. Instead of adopting traditional group definitions, individuals were considered as being members of the same group if photographed within a specific time and space window. This approach can be applied post hoc across studies and can offer advantages under challenging sampling conditions (e.g. when dealing with groups spread over vast areas or when group membership is otherwise hard to assess). Dolphins were mostly found around coastal cage aquaculture facilities farming European sea bass Dicentrarchus labrax and gilthead seabream Sparus aurata. Dolphins formed clusters largely or entirely composed of individuals of the same sex, suggestive of sex‐based homophily. Habitat partitioning was not detected: there was substantial spatial overlap among dolphin clusters, with all individuals using a relatively small area in the northern portion of the Gulf, where most of the productive fish farms were located. Associations between females were stronger than those between males, and daughters tended to stay in the group of their mothers. Sex‐based social clustering may allow females and calves to limit interactions with potentially aggressive males, while individuals of both sexes benefit from prey concentrated around fish farms. Adaptation to foraging around farms can result in trade‐offs between the costs and benefits of nourishment and social interaction. This may have both positive or negative effects on the animals that should be considered in the context of ensuring their favourable conservation status.

Management actions to achieve Favourable Conservation Status for the priority plant species of the Habitats Directive Androcymbium rechingeri (Colchicaceae) in Greece

Management actions to achieve Favourable Conservation Status for the priority plant species of the Habitats Directive Androcymbium rechingeri (Colchicaceae) in Greece

Suitability of Natura 2000 sites for threatened freshwater species under projected climate change

Abstract As part of the world's largest coordinated network of protected areas, Natura 2000, European Union member states designate special areas of conservation (SACs) to maintain or achieve favourable conservation status for imperilled aquatic species listed under Annex II of the Habitats Directive. Long‐term suitability of SAC habitats is potentially challenged by continuing climate change. To examine this emerging threat to aquatic species conservation, the habitat suitability of designated SACs (n = 8,221) for 24 Central European freshwater species (18 teleosts, two lampreys, two crayfish and two bivalves) was assessed under current and projected end‐of‐century climate using environmental niche models calibrated on species occurrences reported under the Habitats Directive (n = 33,995). Potential future conditions included three climate‐change scenarios representing a gradient from effective climate protection measures to a worst‐case warming scenario. Habitat suitability of SACs was consistently calculated as high under present climate but projected to decline severely for two‐thirds of the species under future climate conditions, with the magnitude of decline generally paralleling that of projected climate change. Under high emission scenarios, one third to more than half of the species were predicted to face unsuitable conditions in ≥75% of SACs. Predicted change in habitat suitability varied across biogeographical regions, with Alpine SACs often undergoing lower or no decline in predicted suitability. Given the discrepancy between the location of currently designated SACs and predicted areas of suitable habitat under projected end‐of‐century climate, climate change can be expected to undermine the long‐term effectiveness of currently protected areas. Fostering climate resilience of freshwater habitats within SACs, restoring stream connectivity among SACs, assisted migration to newly suitable SACs where natural dispersal is not possible, as well as designation of new protected areas within climate refugia represent key actions to overcome this potential future conservation gap.

Towards Forest Condition Assessment: Evaluating Small-Footprint Full-Waveform Airborne Laser Scanning Data for Deriving Forest Structural and Compositional Metrics

Spatial data on forest structure, composition, regeneration and deadwood are required for informed assessment of forest condition and subsequent management decisions. Here, we estimate 27 forest metrics from small-footprint full-waveform airborne laser scanning (ALS) data using a random forest (RF) and automated variable selection (Boruta) approach. Modelling was conducted using leaf-off (April) and leaf-on (July) ALS data, both separately and combined. Field data from semi-natural deciduous and managed conifer plantation forests were used to generate the RF models. Based on NRMSE and NBias, overall model accuracies were good, with only two of the best 27 models having an NRMSE > 30% and/or NBias > 15% (Standing deadwood decay class and Number of sapling species). With the exception of the Simpson index of diversity for native trees, both NRMSE and NBias varied by less than ±4.5% points between leaf-on only, leaf-off only and combined leaf-on/leaf-off models per forest metric. However, whilst model performance was similar between ALS datasets, model composition was often very dissimilar in terms of input variables. RF models using leaf-on data showed a dominance of height variables, whilst leaf-off models had a dominance of width variables, reiterating that leaf-on and leaf-off ALS datasets capture different aspects of the forest and that structure and composition across the full vertical profile are highly inter-connected and therefore can be predicted equally well in different ways. A subset of 17 forest metrics was subsequently used to assess favourable conservation status (FCS), as a measure of forest condition. The most accurate RF models relevant to the 17 FCS indicator metrics were used to predict each forest metric across the field site and thresholds defining favourable conditions were applied. Binomial logistic regression was implemented to evaluate predicative accuracy probability relative to the thresholds, which varied from 0.73–0.98 area under the curve (AUC), where 11 of 17 metrics were >0.8. This enabled an index of forest condition (FCS) based on structure, composition, regeneration and deadwood to be mapped across the field site with reasonable certainty. The FCS map closely and consistently corresponded to forest types and stand boundaries, indicating that ALS data offer a feasible approach for forest condition mapping and monitoring to advance forest ecological understanding and improve conservation efforts.

Cost-effectiveness of Natura 2000 forest contracts for biodiversity conservation

Natura 2000 contracts in the European Union aim to maintain or restore natural habitats to a favorable conservation status. This article aims to analyze the cost-effectiveness of Natura 2000 forest contracts at the individual level of intervention areas in France. The level of long-term biodiversity was assessed using ex ante and ex post levels of conservation status, evaluated on a 100-point scale. Data collection was conducted on the contract areas using a combination of plotless and line intersection sampling methods. Cost-effectiveness was analyzed by modeling a cost function of conservation measures that is estimated simultaneously with the ex ante and ex post biodiversity equations. We performed an empirical illustration based on a small number of observations, and, therefore, the results deserve to be confirmed using larger databases. The conservation measures implemented in the contracts studied had a significant effect on maintaining and restoring biodiversity. Nevertheless, we found pronounced diseconomies of scale and low cost-effectiveness. This suggests the possibility of less ecologically ambitious contracts with lower average costs. Our results also recommend new targeting and prioritizing rules to implement more cost-effective conservation measures (e.g., veteran trees) in a less costly context (e.g., targeting main tree species in larger intervention areas). These recommendations could make Natura 2000 contracts significantly more cost-effective.