ESCAPE XXL
- Feedback on exit devices from fences for large wildlife
Feedback on exit devices from fences for large wildlife
In France, wild ungulates, particularly roe deer and wild boar, are able to use escape devices to leave fenced areas. Thus, certain ramps, trapdoors, gates or trigger-wired “open-cage” devices are used on an occasional or more frequent basis. The exploratory project ESCAPE XXL details and illustrates the typology of the escapes and the wide variety of structures. It has also resulted in a compilation of such constructions in Europe and North America.
The use of devices employed in France or in Europe is proven in certain cases but, at this stage, the contextualization and comparison of their effectiveness are limited, if not impossible, given the few protocolised studies available and the very diversity of implementation methods within each type (i.e. dimension, general quality, duplication of standardised equipment or, on the contrary, specific to a site…). Some data remain to be consolidated for France: experience on extraction devices on the railway network, results of monitoring of escape routes on highways, etc.
This exploratory project shows that the scientific investment in escape devices has been greater in North America than in Europe. Their effectiveness and use by cervid species have been studied in North America for ramps and one-way gates, but most of the existing structures have not been studied or monitored. Approaches have focused on the rates of animals exiting or entering, and sometimes on individual behaviour in front of the facilities or on changes in their use over time. Particular emphasis was placed on cost/benefit analyses as part of a general strategy to mitigate animal collisions. Certainly, the North American context is different from France in terms of the species concerned, the way fences are set up, the size of natural areas and the migratory aspect of cervids, with sometimes hundreds of animals using the escape devices during monitoring and the possibility of statistically testing the hypotheses. However, the questions investigated and the protocols followed provide reference frameworks for future research in France and in Europe.
Despite their heterogeneity, the data collected in this exploratory project enable us to draw up a state of current practices, knowledge and questions. For North America, the research work has already led to several literature reviews in the context of academic work or state of the art: they could allow for systematic treatments. At this stage, this does not seem possible for Europe, given the lack of formalised and/or protocolised work: this observation is in itself a result of this exploratory project. Thus, we suggest a list of questions to be methodically investigated for European wild boar, roe deer and red deer in order to better specify the context of use of each type of equipment and to optimize implementation. They concern the following axes:
- Axis 1: define the level of use and efficiency rate regarding the different design modalities within each type of escape device and the environmental context,
- Axis 2: define the influence of positioning on the use of the device,
- Axis 3: optimize existing systems,
- Axis 4: study the legal security of the structures on their installation and over time.
Some questions relate directly to ways of optimising achievements or innovations, others to the general framework of escape devices used on a given infrastructure. Points of vigilance are identified for future protocols.
Finally, to capitalise the results of experience, we suggest that a large fauna escapes database is finalised, within an international framework. Such a database would ideally register geolocalisations or the section of infrastructure concerned and references of the publications relating to each escape device. To this end, ESCAPE XXL provides a first draft compiling all the bibliographic references, survey results and opportunistic data collected.