Abstracts - Public Open Forum

Eisenbeis, Gerhard* and Andreas Hänel
ARTIFICIAL NIGHT LIGHTING AND INSECTS WITH REMARKS TO INCREASING LIGHT POLLUTION

Artificial night lighting replacing the natural dark sky is developing more and more as a serious impact factor on nature and ecosystems. The illuminated area is fast growing from urban areas into surrounding landscapes and along coasts. Many groups of animals are affected by artificial lighting, especially nocturnal insects. There are some indications that the general decline of the insect fauna is accompanied by a high loss of diversity of nocturnal species. Based on a field study it can be shown that the light quality of street lighting systems (e.g. the use of high pressure sodium instead of high mercury pressure lamps) is of high importance to minimise the flight to light behaviour of insects. Experts for outdoor lighting have evolved some principles for good lighting and new ways to avoid bad lighting. Good lighting protects the night sky from wasted radiation with the use of cut-off lamps when possible. This practice spares public budgets by minimising the energy costs, and finally it preserves nature. One way to develop sustainable cities in future is to encourage the environmentally friendly use of artificial lighting. It is proposed that a responsible dealing with artificial lighting should become a guideline both for city planners and landscape architects.

Although the political ambition in Sweden is to integrate the maintenance of biodiversity as well as human well-being into urban planning and monitoring, implementation is hampered by the lack of significant landscape data. The main goal of this study is to visualise spatio-temporal properties of the biodiversity concept for use in contemporary physical planning in Stockholm through: 1) applying a user perspective, 2) identifying methods forming complementary planning tools, 3) mapping of comprehensive biotope patterns. Trans-disciplinary methods, i.e. aerial photographic interpretation, GIS, field-surveys and logistic regression analysis are combined targeting wetlands and spontaneous woodland successions. The developed comprehensive reference data (biotope database and species records) increased the insight into the ability of ecosystems to buffer land use changes. With this complementary information, the relative importance of subsequent biotope loss and changes in stress levels in different areas were more readily assessed. A proposed time-lag of several decades between land cover changes and species responses was confirmed in wetland networks. This time-lag is not appreciated in present day short-term planning. The present approach does not provide a complete template applicable to all urban landscapes. It shows, however, how different disciplines and their perspectives may be combined and used in urban planning.

My students and I study birds and small mammals to understand how fauna respond to the fragmented landscapes found in cities. We study how species use habitat patches in cities to understand how species composition and abundance is influenced by the history of the patch (remnant, planted, or emergent), the matrix surrounding the patch, and current factors influencing the patch. We focus on two types of patches: large patches of remnant natural habitats where we assume that species composition will be influenced largely by habitat features; and small patches adjacent to residential neighborhoods where people and their activities may influence species composition. An understanding of how species use both types of patches is important in understanding the fauna of cities.

Roads are conspicuous components of landscapes throughout the world. Road networks are continuing to expand, as new roads are constructed or existing roads are widened to accommodate an increasingly mobile society. Other linear infrastructures, such as powerlines and railways, also dissect and fragment landscapes. The ecological impact of roads and traffic are potentially profound as the "road-effect zone" (after Forman et al.1997) may extend for many hundreds of metres either side of the road. Roads can have both positive and negative effects. For example, roads necessarily result in the loss of habitat, can cause the degradation of adjacent habitat and act as a barrier or filter (e.g. roadkill) to the movement of fauna. On the positive side, vegetation along roadsides often represent the only native habitat in highly cleared landscapes, and thus have significance for the conservation of biodiversity and maintenance of landscape processes. The significant challenge for management and conservation is to identify and quantify the extent to which roads and traffic disrupt and modify ecological processes and construct systems that minimise the negative consequences. The extreme cost to build a road in terms of dollars and potential environmental impact demands that we get it right the first time.

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