In the karst landscape of the Kras Plateau (south‐west Slovenia), we studied the impact of historical human‐induced land degradation on biodiversity by studying the characteristics and changes in ...vegetation of degraded and nondegraded karst depressions (dolines). Intensive human‐induced land degradation began as a consequence of the abandonment of traditional land use; thus, many dolines have disappeared by being completely filled with waste material and overgrowth. The study is based on a chronosequence approach and assesses whether vegetation (e.g., community succession stages) can be used as a (bio)indicator of land degradation to estimate approximately the duration of degradation on the basis of the stage of succession. The locations and duration of degradation of dolines were identified in advance by analysing a time series of historical aerial photographs, topographical maps, and digital elevation models. Ecological evaluation was based on sampling the floristic composition and the topsoil. In this study, three vegetation measures were established as indicative of degradation: (a) the appearance of ruderal species, (b) hemeroby, and (c) alien and invasive species. A succession model of degraded karst landscape was produced on the basis of identified chronosequences to assess the long‐term spatial impact of doline degradation on karst biodiversity. The model is showing the tendency towards the vegetation homogenization of karst landscape.
•Dolines can be divided into landform-vegetation units.•They reflect geomorphic characteristics, biodiversity and ecological conditions.•They can easily be identified in the field by indicator ...species.•Only some dolines can serve as safe haven for cool-adapted species.•The methodology is transferable to other regions.
In this study, the objects of research were circular and concave karstic depressions, called sinkholes or dolines. All these negative topographic anomalies were previously recognized as safe havens for cool-adapted species on karstic plateaus. However, the high geodiversity of doline landforms on karst plateaus does not ensure that all dolines are really safe havens that should be considered for conservation status. We propose the use of indicator species to identify different dolines' “sections” and their overall types to identify dolines with high conservation value for cool-adapted species. We aimed to divide dolines into landform-vegetation units (LVU) according to basic geomorphic characteristics and indicator plant species.
We carried out intensive sampling of vegetation plots (n = 286) across 10 dolines of different geomorphology ranging from 20 m to 100 m in diameter and from 2 m to 20 m in depth. Each doline was classified into a maximum of four LVUs: bottom, lower slope, upper slope and top. Vascular plants were used as a proxy for ecosystem biodiversity and indicator of ecological conditions. The diversity of vascular plant communities was sampled along N–S transects from one side of the doline over the bottom to the other side. Geodiversity parameters of individual dolines were calculated using a high-resolution digital elevation model (LiDAR / Light Detection And Ranging) and their significance was established by permutation test in CCA (Canonical Correlation Analysis). The floristic gradient was established by the first axis of PCoA (Principal Coordinates Analysis) and shows the species turn-over along the trajectory. Discrete plant communities were determined by TWINSPAN (Two-Way Indicator Species ANnalysis) classification. Based on this analysis, transects were disintegrated into four LVUs. Communities within LVUs were compared by Ellenberg indicator values and according to habitat preference of species. The indicator (also termed diagnostic) plant species were calculated by fidelity measure and related to ecological conditions along transects.
We found that all four LVUs appear only in dolines that are at least 13.5 m deep and those can serve as a good safe haven for cool-adapted species in foreseen climatic change. We also confirmed that doline depth is the most important factors influencing the plant community composition. The results can be directly transformed to other karst regions (karst plateaus) with the same zonal vegetation, but calibration is needed in case of their application in other areas.
One of the frequently used bioindication methods is Ellenberg indicator values (EIVs), which are commonly applied in Central Europe as bioindicators of ecological characteristics. However, very few ...studies have tested EIVs as a bioindication of human-induced soil degradation.
We tested the ability of EIVs to distinguish between localities of degraded karst depressions (dolines) and localities of semi-natural (agricultural) soils in preserved dolines on the Kras Plateau (Classical Karst, SW Slovenia). We compared the results of bioindications of soil nutrient content (N), soil reaction (R) and soil moisture (M) with measured soil parameters.
Low values of organic carbon, a slightly alkaline soil reaction and low organic sulphur content are chemical indicators of soil degradation in dolines, in comparison with preserved reference dolines (high organic carbon, slightly acid reaction, higher S).
EIV reaction is the most reliable plant indicator value that can distinguish between degraded and non-degraded soil plots. According to a regression tree, sulphur (S) and C/N are the most important factors for division on the basis of EIV reaction. By applying the EIV reaction of diagnostic plant species, we significantly improved bioindication of soil degradation, although in the case of EIV nutrients, bioindication was not improved.
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•EIV reaction is the best bioindicator of soil degradation in dolines.•EIV reaction can best predict C/N and sulphur (S) soil parameters.•EIV results can be refined by the use of diagnostic species.
Karst landscapes have an abundance of enclosed depressions. Many studies have detected depressions and have calculated geomorphometric characteristics with computer techniques. These outcomes are ...somewhat determined by the methods and data used. We aim to highlight the applicability of high-resolution relief laser scanning data in geomorphological studies of karst depressions. We set two goals: geomorphometrically to characterize depressions in different karst plateaus and to examine the influence of data preprocessing and detection methods on the results. The study was performed in three areas of the Slovene Dinaric Karst using the following steps: preprocessing digital elevation models (DEMs), enclosed depression detection, calculating geomorphometric characteristics, and comparing the characteristics of selected areas. We discovered that different combinations of methods influenced the number and geomorphometric characteristics of depressions. The range of detected depressions in the three areas were 442–491, 364–403, and 366–504, and the share of the depressions’ area confirmed with all the approaches was 23%, 29%, and 47%, which resulted in different geomorphometric properties. Comparisons between the study areas were also influenced by the methods, which was confirmed by the Mann–Whitney test. We concluded that preprocessing of high-resolution relief data and the detection methods in karst environments significantly impact analyses and must be taken into account when interpreting geomorphometric results.
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•Thick clay-silty Luvisols in the bottom of dolines have high SOC storage capacity.•Past agricultural land-use presents long-term impact on SOC stock in dolines.•Succession plots in ...dolines show the highest SOC storage capacity (130 t/ha).•Soil organic carbon stock in dolines was double the amount on the levelled plateau.
The soil organic carbon (SOC) was determined in soils of enclosed karst depressions (dolines) (NW Dinaric Mts.) to define their potential for organic carbon sequestration. SOC was measured in the forest, succession (scrubland), and grassland plots at the bottom of dolines at four depths (0–40 cm) and for 40 cm soil layer SOC stock was calculated. We demonstrated that the prevailing fine soil fractions, the C/N ratio and soil thickness play a positive role in the storage capacity of SOC in dolines regardless land use type. Grasslands have the lowest SOC storage capacity (106 t/ha/40 cm), while the highest SOC storage capacity is in succession plots (130 t/ha/40 cm). The last are covered by shrub communities dominated by Prunus spinosa, forming dense communities, and are typical of abandoned croplands or meadows that have been impacted by high levels of nutrients during cultivation phase. At this stage, there is no additional nutrient input in studied plots, which lowers the nutrient content and increases the C/N ratio. C/N ratio is the highest in the forest, where SOC stock capacity is 116 t/ha/40 cm. Given the trend towards the abandonment of agricultural land at Kras Plateau (SW Slovenia), we can expect more overgrowth of dolines, and thus an increase in carbon stocks and stabilization of organic carbon in forest soils. In contrary, we noticed the alarming decrease in grasslands and increase in urban land. The SOC storage in 2020 was for 12,538 t/ha/40 cm lower than in 2002. Although grasslands showed the lowest SOC storage, their contribution to total SOC storage in dolines is very important. Since there is a lack of studies on carbon stocks in doline soils, our research is of great importance and a novelty and gives an important background for further research on SOC stock in karst landscapes worldwide.
Dolines are depressions in karst landscapes that are of high value for conservation, providing habitats and supporting species not found in the surrounding landscape. This is due to their high ...microhabitat diversity and ability to decouple microclimate from regional climate changes, making them potential refugia for biodiversity. Nevertheless, local anthropogenic disturbances have had considerable impact on the species composition and vegetation structure of many dolines. Here we investigate the conservation value of dolines in three European karst areas, where different levels and types of anthropogenic disturbances have been shaping the vegetation for centuries, using the number of plant species that are cool-adapted, moist-adapted and of high conservation importance (i.e. vulnerable species) as indicators. We found that anthropogenic disturbances generally have a negative impact, reducing the number of vulnerable species supported by dolines. However, more cool-adapted and moist-adapted species were found in some dolines planted with non-native
Picea abies
than in less disturbed dolines, indicating that anthropogenic disturbances can also have positive consequences for biodiversity. We conclude that anthropogenic disturbances alter the capacity of dolines to support vulnerable species, and that this will impact survival of species in landscapes under global warming. In this context, the effects of various disturbances on species composition and diversity need to carefully considered to determine the best conservation and/or management options.
Context
Many carnivores are attracted to rugged terrain, rocky areas, and conspicuous relief features. However, most of the previous research is limited to general topographical habitat ...characteristics and rarely consider the effects of microhabitat characteristics.
Objectives
We used the Eurasian lynx (
Lynx lynx
) as a model species to investigate the effects of microhabitat characteristics and human infrastructure on habitat selection. We also tested whether there is evidence for a functional response in habitat selection across a large gradient of habitat availability.
Methods
We developed a new approach for detecting rocky outcrops from airborne LiDAR data. In combination with other remote sensing techniques and GPS-telemetry data, we assessed lynx habitat selection and functional responses across two geologically contrasting areas in Europe.
Results
We detected > 1 million rocky outcrops and confirmed their strong selection by lynx. Lynx also selected steep, rugged, and rocky areas, especially for day-resting sites. Furthermore, lynx avoided paths during the day but selected them and other linear anthropogenic infrastructure during the night, indicating the behaviour-specific impact of human infrastructure. We also observed a functional response in the selection of rocky and rugged areas, as lynx’ selection of such habitats increased with their lower availability. This highlights the importance of preserving such terrains, especially when they are rare in a landscape.
Conclusions
Our results highlight the importance of incorporating remote sensing techniques and data on microhabitat features in animal habitat selection research. We also recommend caution when developing new infrastructure for human recreation or promoting its use near geomorphological features and in rugged terrain.
Automatic methods for detecting and delineating relief features allow remote and low-cost mapping, which has an outstanding potential for wildlife ecology and similar research. We applied a ...filled-DEM (digital elevation model) method using LiDAR (Light Detection and Ranging) data to automatically detect dolines and other karst depressions in a rugged terrain of the Dinaric Mountains, Slovenia. Using this approach, we detected 9711 karst depressions in a 137 km2 study area and provided their basic morphometric characteristics, such as perimeter length, area, diameter, depth, and slope. We performed visual validation based on shaded relief, which indicated 83.5% accordance in detecting depressions. Although the method has some drawbacks, it proved suitable for detection, general spatial analysis, and calculation of morphometric characteristics of depressions over a large scale in remote and forested areas. To demonstrate its applicability for wildlife research, we applied it in a preliminary study in combination with GPS-telemetry data to assess the selection of these features by two wild felids, the Eurasian lynx (Lynx lynx) and the European wildcat (Felis silvestris). Both species selected for vicinity of karst depressions, among which they selected for larger karst depressions. Lynx also regularly killed ungulate prey near these features, as we found more than half of lynx prey remains inside or in close vicinity of karst depressions. These results illustrate that karstic features could play an important role in the ecology of wild felids and warrant further research, which could be considerably assisted with the use of remote detection of relief features.
We analyzed plants and their traits in dolines, which are characteristic enclosed terrain depressions on carbonate (karst) plateaus. These landforms range from a few meters to over 100 m in diameter, ...their depth generally varying from a few meters to a few tens of meters. A pronounced ecological gradient can be found from the bottom to the top, starting from humid, cool and shaded bottoms to sunny, dry and warm slopes and tops. We sampled dolines of various depths and analyzed the distribution of plant species on the gradient and how this distribution is reflected in plant traits: chorotypes, life forms, plant architecture and strategies. We used the transect method and sampled the floristic composition from the doline bottom to the top. We collected information about plant traits from various literature sources. The results show life forms and plant architecture explain this gradient well and, to a lesser extent, also chorotypes, but functional strategies have a low explanatory power. Life forms and plant architecture are the result of adaptation of species to the environment, and chorotypes are defined as species with an overlapping geographical distribution pattern due to their distribution and environmental histories. Functional strategies, which have evolved to enable plants to succeed in various environments, unexpectedly have a low explanatory power.
Background
This study deals with wildfires in marginal areas of the Mediterranean climatic and biogeographical regions (Northern Mediterranean) where fires were not common. The aim of the research ...was to determine the differences in floristic composition and traits at different intensities of fire damage and to analyze the changes in forest ecosystems during the wildfires that took place in the summer of 2022. The study included both the zonal forests and non-native black pine (
Pinus nigra
) forests. Remote sensing techniques linked to the vegetation data sampled in the field during the 2023 vegetation season, the very first season after the fires, were also used in the fire assessment.
Results
The study confirmed that satellite data analysis, orthophoto interpretation, and on-site vegetation sampling provide equivalent information on fire severity, opening up the possibility of transferring knowledge to similar post-fire sites without field sampling in the future. TWINSPAN classification analysis divided the sampled plots into clusters based on tree species prevalence and fire severity. The diagnostic species of the clusters were calculated using a fidelity measure. Ordination revealed that the first axis on the detrended correspondence analysis (DCA) correlated with wildfire severity. Ecological conditions and strategies, life forms, chorotypes, seed dispersal classes, and regeneration traits were analyzed along this gradient. We found that post-fire sites became warmer, drier, and lighter, which favored the growth of ruderal, theropytic, cosmopolitan, anemochorous and post-fire emergent species. After the fire, a “wave” of annual ruderal species was observed.
Conclusions
The results indicate that post-fire recovery can be left to natural processes without human intervention, except in the case of non-native pine stands where planting or seeding may be necessary. Otherwise, it is essential to control the possible occurrence of invasive species. Isolated adaptations of species to fire have also been observed, such as heat-stimulated germination. Such adaptations could develop in regions exposed to frequent fires and where fires act as an evolutionary factor.
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