Management and construction of rail infrastructure habitats for biodiversity

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Background

Recently, it has been shown that many parts of the railway system, in particular at stations, are surprisingly species-rich and constitute important refugias for threatened insects of several groups. As for species-rich road verges there are indications of declining biodiversity values also in railway infrastructure habitats (RIH).

In order to enable proper measures for maintaining and forming of biodiversity-rich RIH we need better knowledge about the ecology and threats of different RIH in relation to different management methods. With such knowledge we can evaluate the limitations of the present management and suggest changes. 

Activities

This subproject will use field data to analyse which environmental conditions, including management, that constitute ecological key factors for different biodiversity values (e.g. species groups) in RIH. The ongoing management will be regarded a large-scale experiment and evaluated in order to discern effects of different maintenance and construction activities on those key factors. A number of modifications of management and new management methods will be tested as new experiments.

The subproject aims at understanding the ecology of the railway station habitats, in particular the relationships between occurrences of species of conservation concern, the micro-environmental variation within the station, and the ongoing activities for maintenance (for example ground vegetation control and shrub clearing) and construction (which cause soil disturbance and new vegetation successional stages). 

We will investigate which environmental factors (related to management, substrate etc.) that account for the biodiversity values of RIH, known from earlier surveys by Trafikverket.

Since RIH can be considered ruderal, highly unstable, habitats, vegetation analysis is not appropriate. Instead, we will use a species based approach, in which characteristic or threatened species, or species with key habitat or community functions, will be analysed with respect to their specific micro-environment, which can be assumed to reflect their environmental needs and threats. Vascular plants, insects, and some cryptogams have been subject to earlier inventories by Trafikverket, and will be analysed in this sub-project. The micro-environment is characterised by ground substrate, successional stage, disturbance regimes, exposure etc, which implies that the overall habitat may be characterized by certain dynamics. A model for structured data collection of species’ microhabitats has been developed earlier and generated some information. The model will be used to collect complementary field data on species microhabitats.

In order to get as strong as possible connection to management, sites which have been subject to known management activities, including previous experiments in TRIEKOL I-II, will be evaluated specifically. Such activities include alternative measures for shrub clearing (pulling instead of cutting), ground vegetation control, and soil handling. Activities also include measures for control of invasive species. 

Data on species-microhabitat relationships will be derived from Trafikverkets earlier inventories, and from new field surveys, in which we use earlier inventories to locate the species. Ecological effects of recent and ongoing management activities (including earlier experimental ones) will be analysed using earlier monitoring data combined with more thorough monitoring during the project period. These studies can be regarded a use of Trafikverkets ongoing activities as a large “living” field experiment. In addition, a number of particularly important management activities will be identified early in the subproject and tested in specific experiments throughout the project period. 

Data will be analysed in order to identify which environmental variables that constitute ecological key factors for different groups of species of conservation concern in RIH, and how these variables are formed by different combinations of activities for maintenance and construction. We will use methods for combined qualitative-quantitative cluster analysis and species-habitat models developed at Swedish Biodiversity Centre. 

The results will be published scientifically.

Output

  • Knowledge about which ecological conditions and processes (ecological key factors) that account for species of conservation concern, species richness, and important biological functions of rail IH.
  • Knowledge about how such ecological key factors can be obtained by management activities.

In total, these results will provide a necessary, but today largely lacking, knowledge base and a cost-efficient toolbox for planning, prioritizing, performance, and monitoring, to be used in activities for maintenance and construction of RIH. The results will significantly contribute to preserving and developing the biodiversity values of RIH at maintenance and construction. 

Study areas

Biodiversity values in broad sense are known for a large number of stations, through Trafikverkets own inventories during the last years, and the data that have been used to classify the stations according to degree of conservation concern (three classes). Inventories are largely spatially explicit, for example in terms of species occurrences. 

Management activities for biodiversity have been performed on 27 stations, and monitoring of the activities has been launched, which can be continued within the subproject. On five of these stations, more elaborate experiments and effect monitoring have been performed (Byvalla, Jordbro, St. Tuna, Gustafs, and Avesta-Krylbo). Altogether, this background information and planned activities provide an excellent opportunity to evaluate ongoing and previous activities, and to design new management experiments to follow from the beginning. 

Beginning in 2017, a new set of stations will be subject to management activities (ca. 15 stations, tentatively). Initially in the project, suitable study sites will be selected based on existing information combined with some additional field information. We will combine in-depth studies of the ecological conditions and variability at five stations, with studies of specific microhabitats and management methods at a larger number of stations (c. 10). 

Deliverables

Seminar biodiversity in railway habitats 

A Swedish seminar (Biologisk mångfald i järnvägsmiljöer) presenting current knowledge, research results and management trials was held in Stockholm 15 Jan 2019. All documentation from the seminar can be found at the seminar web page.

Photo: Jörgen Wissman