Research team:
Coordinator
Researcher´s:
Mgr. Oldřich Čížek
Mgr. Pavel Marhoul
Ing. Lada Jakubíková
The importance of stone quarries for diversity of invertebrate in fragmented landscape on national level (ACTIVITY 9)
Goal of ACTIVITY 9 is 1) monitoring of monitoring of invertebrate diversity in stone quarries within the national measuring scale 2) study of benefits of stone quarries for general diversity of the mostly fragmented modern landscape 3) searching for key environmental factors influencing colonization and biota persistence at these stations.
Research state:
It has been established during explorations in the last 20 years that un-recultivated stone quarries host a rich fauna and flora with a considerable representation of species on national Red Lists. However, other research shows that what currently grows or lives in stone quarries is the outcome of colonisation, mainly from the close vicinity of a quarry (with vascular plants the role is played the first one hundred metres from the edge of a quarry). On this supposition stone quarries should increase the biodiversity of the nearest species only little. If this is not so, the surrounding landscape must have changed since the times of extraction or stopping of extraction. A great part of the cultural landscape has been changed to a considerable homogeneous landscape and unique communities survive to this day in quarries in a refuge of sorts from the times when most species found suitable biotopes in the fine landscape mosaic in the locality. In this case it can be expected that the presence of a stone quarry increases the overall biodiversity of the landscape. Yet the structure of the local landscape with a stone quarry need not be influenced merely by the stone quarry, but also by the present elements related to extraction, such as approach roads, planned extraction spaces, and the like. Landscape can thus be better permeable with these elements with lower fragmentation of important habitats or with a far finer landscape mosaic.
The aim of this project was to point out this fact, i.e. whether a local landscape with the presence of a stone quarry reports at present a lower degree of fragmentation of biotopes and whether in such a type of landscape it is possible at present to maintain more demanding, in particular xerothermic invertebrate specialists. As for the species on the Red List, it will be assessed whether it is possible to use stone quarries in rescue programmes for the most threatened taxons, and last but not least, make use of standard methods to add to the information about the invertebrate fauna in stone quarries and the closest surrounding landscape.
In all, 20 abandoned stone quarries, largely in the warmer areas, were chosen in the territory of the Czech Republic. A square was delineated around each one with one kilometre per side. A similar square was delineated at a distance up to five kilometres without the presence of a stone quarry, so that the composition of the basic habitats (water, field, forest, and grassy surfaces) was proportional in both adjacent squares. The landscape mosaic was then described in all the squares by type and size of the landscape grains. Data were collected in these square surfaces during the 2015 season on the diversity of the selected classes of invertebrates (day and night butterflies, orthoptera, neuroptera, empoasca, heteraptera, carabidae, curculionidae and elateridae beetles and spiders), selected to fit most of the trophic levels and ecological gilds of the community of invertebrates, and at the same time, to show general differences in dispersion abilities. These families were collected with standard methods: day excursion (butterflies – four visits per season, orthoptera – one visit) on the surface of selected squares, luring to light sources (portable light traps– five traps per square, a total of four collections), land traps (ten traps per square, a total of three collections) and quantitative swathes of vegetation around the land traps (a total of three collections). The numbers of traps and light traps in the individual habitats were proportionate in the squares to the surface of a square. Inside the quarry two land traps were exposed and one light trap. The collected material was then divided into groups and determined at species level. One conservation status was assigned to each family according to the Red List of Invertebrates and the degree of its bond to xerothermic habitats. The data were then analysed using models with a paired design.
The structure of the nearest landscape around a stone quarry was markedly different from a landscape without a stone quarry. More landscape grains and their relatively smaller size were present in surfaces with a stone quarry. Moreover, in a landscape with a stone quarry there were more field blocks (smaller in size and hence more ruggedness) and more surfaces with scattered greenery (shrubberies, forest steppe formations). Landscape in the vicinity of a stone quarry is more varied, with smaller grains and lower degree of fragmentation (more landscape grains leads to a greater proportion of edges and boundaries of grains and therefore better connectivity). Overall species diversity did not vary between squares or was higher in the squares with stone quarries. Species were recorded in each group under review from the Red List and in some groups also a distinctive representation of xerothermic specialists. Looking at the representation of xerothermic specialists presence was higher in most groups in squares with a stone quarry. These groups of species were studied in detail and it was found that in a stone quarry they were not present merely within a stone quarry (predominantly groups tied to rocky habitats and loosened xerothermic grass plots), but they were also distinctive around a stone quarry. Extraction work, that is the original elements related to extraction, could therefore contribute to the creation of a finer landscape structure providing appropriate surfaces for xerothermic specialists (in particular, families of xerothermic shrubberies, dry grass plots etc.). What is important for landscape protection goals is not merely the actual space of a stone quarry, limited in size in many cases, but also the character of the surrounding landscape, with the ability to maintain the diversity of the specialise families and a better permeability in general.
None of the families involved in the current rescue programmes was noted during the project. Incidence of a number of species classified among the critically endangered or endangered species specialising in rare was xerothermic habitats was registered. Stone quarries with surrounding landscape can thus create appropriate conditions for their maintenance and dispersion in the landscape, and can be included in rescue projects at the level of the landscape. For invertebrates with a meta-population structure it is moreover the only solution for saving their populations.
Based on the results of this project we can see the considerable potential of stone quarries for xerothermic specialists, though not only with a view to the actual space of un-recultivated stone quarries offering alternatives to early success stages but also the character of the surrounding landscape. This landscape is more variable, with a finer landscape mosaic, and hence a greater representation of eco-tonal interfaces and xerothermic surfaces and patches. As the study shows, in such a landscape there are more species of xerothermic specialists, with a link to later open successive xerothermic stages, which complements well the offer of early successive surfaces in stone quarries. These specialists may be linked to habitats inside stone quarries, although they may survive outside their stone quarry.
Seeing the rare types of biotopes the landscape around stone quarries can be characterised as less fragmented with lesser isolation of individual target fragments, and hence more permeable for xerothermic specialists. Such a landscape therefore has a relatively high potential for maintaining species with structured populations (e.g. with metapopulational structure) dependent on a suitable landscape mosaic. At present many research teams are making efforts to adopt measures endeavouring the maintain xerothermic habitats inside stone quarries (and other post-extraction spaces). These efforts are of high importance for active nature conservation and are crucial for preserving a great diversity of the most threatened xerothermic specialists. Their importance for families with structured populations and greater demands for the extent and accessibility of the key habitats can be fully appreciated in the form of extensive posts, such as large coal dumps. Only a sufficiently large expanse of a given brownfield can provide a space for the creation of a sufficiently diverse landscape mosaic so that it ensures the survival of these populations. As for the stone quarries, if we pass over the huge stone quarries like the Devil’s Steps in the Czech Karst, these are rather smaller objects, which despite all efforts cannot maintain such a population on their own in the long run. For them they may have some importance as provisional stepping stones in the landscape. Therefore, it is necessary in the case of these (with a similar size) into account the potential and character of the surrounding countryside.
The interim project results were presented at an international lepidopterological conference in Prague. Some of the important fauna findings were published in a specialised arachnological journal (including first findings of two spider families in the territory of the Czech Republic). Interim fauna findings were entered into databases for mapping the distribution of the individual groups.
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