How (not) to protect and monitor the Siberian flying squirrel - an interdisciplinary synthesis

Abstract

Monitoring and evaluation are crucial components of informed decision making, but there is still a general lack of evaluation of the effectiveness of different conservation policies and practices. Also, many existing monitoring schemes can be inefficient use of resources. We have studied the effects and side-effects of legal protection of the Siberian flying squirrel Pteromys volans in Finland, and re-evaluated the methods and results of the monitoring scheme for the species. This presentation combines the results of four different studies.

Protection of the so called 'breeding sites or resting places' for the species has faced resistance. We explored reasons for negative attitudes by comparing the responses of persons with and without direct experience on protection. Forest owners have been mostly satisfied with the logging restrictions, but about half of the area occupied by the species in Finland could be owned by persons who would prefer not to have it on their lands. The issue is politicized: the species has become an example of top-down protection, resisted by forest owners out of principle.

We estimated the proportion of 'breeding sites or resting places' that have been considered in forest management and found that only 3% of all the potential sites that would have been located on logging areas could have been recognized (1). This, and negative attitudes toward the species, indicate severe problems with compliance of legislation. We also studied 100 sites delimited by environmental authority. Our results show that the narrow definition of the prohibition to 'deteriorate or destruct' the sites does not safeguard the ecological functionality of them (1).

The national monitoring scheme reported 22.7% decline of occupancy during 2006-2015. If the proportional change in occupancy would correspond 1:1 with the proportional change in population size, the decline in population size would have been <30%. Based on this assumption the status of the species was down-listed from 'Vulnerable' to 'Near Threatened'.

We estimated a) the relationship between observed decline in occupancy and the true changes in the population size, and b) the possible causes of the change by: i) evaluating the sampling method, building both ii) a survival/colonization model with relevant habitat data, and iii) an individual-based simulator to test the relation between observed occupancy and actual number of individuals. Our simulation shows that population can decline faster than occupancy.

We should rethink the way the species is protected and how its status is evaluated. Protection of only known nest sites will not be effective in Finland. The raw occupancy data should be interpreted according to more realistic occupancy-abundance relationship.

1. Jokinen, M., Mäkeläinen, S. & Ovaskainen, O., 2015. 'Strict' yet ineffective: legal protection of breeding sites and resting places fails with the Siberian flying squirrel. Anim Cons 18: 167-175.