Research team:
Coordinator
Researcher´s:
Mgr. Pavel Marhoul
Mgr. Tomáš Kadlec, Ph.D.
Highway as a potential migration corridor and refuge of invertebrate. Complex assessment of highway existence for diversity of invertebrates (ACTIVITY 8)
The European landscape nowadays is covered with thick net of highways and other types of roads. In the ongoing scientific discussion about the effect of linear structures on the landscape, stations and species, mainly their fragmenting effect has been accented. Biologists and environmentalists do not systematically observe the role of highway as a migration corridor or substitute biotope for stations that have vanished from our landscape. The aim of ACTIVITY 8 is, to gather new standardized data and complete the existing data about fauna of chosen groups of invertebrate. The data will be used for a study of biological and environmental importance of highway banks and grooves. Data presentation in the form of database notes found within the databases (NDOP, specialized database for selected lines)
Research state:
Reduction in biodiversity, which is a global ecological problem, is caused by a combination of factors, the most significant being homogenisation of the countryside and destruction of some valuable biotopes. In relation to these factors a great and interrelated role is played by a loss of connectivity in the landscape. Therefore, not only in our country are different types of corridors constructed aiming to decrease landscape fragmentation and allow migration of a number of organisms. Practical experience shows, however, that these are largely inoperative solutions aimed at vertebrates and forest habitats of organisms. The most threatened species not only in our country but also in central Europe include insects, in particular those living in warm lawns and shrubberies.
Present-day European landscape is intersection by a dense network of roads and motorways. Although there are 1,213 km of motorways in the Czech Republic, conservationists and biologists pay scant attention to these extensive linear elements. Yet the surroundings of the existing facilities require continuing care and maintenance, and with a slight modification of the alterations the funds thus expended could bring a marked added benefit. Their surroundings include a mosaic of rock crevices, places with exposed soil, open and connected lawns and shrubberies. Due to motorways we seldom or never find this type of biotope in a landscape. A number of species of insects and plants are expected to migrate along these lines, which can represent an important refuge for the surroundings.
The aim of our project was to assess the importance of the line structures, bio-corridors and refuges with respect to the individual classes of invertebrates. Our indicators were obtained by collection and adding to the existing standardised data on the fauna of selected classes of invertebrates that could be used for a study on the biological and conservationist importance of motorway verges and furrows and their presentation in the form of database records in the databases of findings, and to assess the state of the identified populations of conservationist importance. The planned outputs included drafting of documents for scientific publications and popular articles, and last but not least, developing methodological theses for the construction of new motorway verges and maintenance of the existing ones.
To achieve these goals we made use of available published and unpublished data and results. For the necessary analyses we collected own appropriately structured data.
The model classes were Lepidoptera, Orthoptera, Hymenoptera, and selected families of Coleoptera and Araneae. In view of the classes and aims we employed three basic collection methods. For all the model classes except Lepidoptera we monitored the effects of five alterations of the motorway element: thin lawns, connected lawns, thin shrubs, connected shrubs and forest lands. The choice was repeated with a view to the climatic areas. In all, we repeated it forty times (with five types of biotope). In selected places we placed three times in a season Möricke traps and ground traps. For the research we chose the motorway D1. The same motorway was used for research on the Lepidoptera. As the representatives of this group are mobile, we chose transects. Each transect was 2 km long and divided into 4 parts of 0.5 km each. In total there were 40 repeats and the transects thus measured 80 km. During the season each transect was visited three times to examine all the seasonal aspects. Employing both methods we recorded the parameters of the motorway element and the climatic factors. For the research on the importance of motorway verges we reviewed all the sections of Czech motorways, and chose 20 most valuable points to carry out research on the species diversity of the selected model classes.
Within all the studied surfaces we collected 6,058 individuals constituting 2,221 records from the classes Lepidoptera, Orthoptera, Hymenoptera, Coleoptera: Carabidae, Curculionidae, Elateridae, Araneae. All these data were added to the Nature Conservation Agency database.
We discovered a total of 25 protected species of 3 orders and 38 species on the Red List belonging to 5 orders (no order was found listed in the Natura 2000 system). All the species that have a priority in conservationist terms are listed in the final report together with concise information about their demands.
The collected data were further processed and analysed in order to find how motorway verges are valuable for individual classes of invertebrates and how alteration of a verge effects their incidence and effect. It was found, for example, that motorway verges suit different classes to varying degrees. For example, the species diversity of butterflies and daily Orthoptera was narrower than we had expected. As stridulation plays an important role for Orthoptera, it is likely that this group of individuals is adversely affected by traffic noise. Daily butterflies, in contrast, are susceptible to wind, and it is possible that wind gusts caused by lorries driving past trouble them. This theory suggests that, on the verges that reach higher latitudes, there were generally higher species spectra. It was also found that for butterflies’ species diversity and occurrence alterations of a verger have only limited influence. Conversely, it appears that an important role is played by the surroundings. It is therefore likely that for butterflies the highway vergers are not a refuge but rather they fly in from the surroundings. On the other hand, some of the results indicate that they help at least in a limited fashion to the distribution of individuals of this class. For all other monitored groups the form of alteration of a motorway verge plays a more important part. It effects particularly strongly the species in the classes Orthoptera and Hymenoptera. For the Hymenoptera places with thin lawns represent valuable biotopes where a number of species on the Red List have been identified. We plan to publish all the results in several articles in impacted foreign journals and to use them to popularise the problem in Czech popular-science magazines. We also plan to present the findings at academic conferences. Using the findings we drafted methodological theses for the construction of new motorway verges. This is an important part of the research because in the Czech Republic it is planned to build another 959 km of motorways. Our research has shown that on new motorways with higher investments in verger alterations there is a lesser incidence of places suitable for insects. It seems ideal to make the least some interventions, for example if bedrock is exposed during a construction, it is appropriate to leave it without alterations and do the securing (instead of costly installations of steel meshes) by terracing, for example. It is also appropriate to leave at least some verges to natural succession and not to sow or plant on them expensively. Bringing added value to the alteration of motorway verges through the creation of suitable conditions for insects would not make the construction more costly; it would even be cheaper. Management proposals were drafted for the existing motorway verges whose implementation would lead to support for species diversity of insects, but would also lead to savings in the maintenance costs. All these outputs are part of the final report and, in addition, we want to present the results to the competent authorities: the Ministry of the Environment, the Nature Conservation Agency, and the Road and Motorway Directorate.
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