Help on radio-tracking Pyrenean desman

Carlos Romco carlos.romao at MAIL.TELEPAC.PT
Sun Apr 13 10:54:23 EST 1997


Radio-tracking Pyrenean desman (Galemys pyrenaicus)

Pyrenean desman (Galemys pyrenaicus) is a small aquatic insectivore that
inhabits the northern part of the Iberian Peninsula and the Pyrenean region
(countries are Portugal, Spain and France). It rarely exceeds 70 grams.
Only another species belongs to the same sub-family (Desmaninae): Desmana
moschata inhabits Don, Volga and Ural basins and the upper Dnieper area
(countries are Russia, Byelarus, Ukraine and Kasakstan). It can reach 625
grams, with an average of 450 grams.

We are studying desmans in Portugal since the end of 80's. The species is
considered Vulnerable by the IUCN and by our national Red Data Book. The
main priority was distribution, habitats and the inventory of threats, but
we already initiate population studies. 
This summer, we intend to start radio-tracking. Our general objective is
species conservation. Data related with dispersion and species ability to
cross physical and ecological barriers (for example dams or highly polluted
sections of the watercourses) are missing. They are crucial to assess
impacts of some river projects.

For Pyrenean desman, Stone (1985) was the only researcher that studied
movements and temporal patterns using radio-tracking. He attached the tag
to the base of the tail. This study is pioneer and gave precious data for
the current knowledge of the species. A disadvantage of this method is
animals can be wounded by the cable-ties that support tags.
The base of the tail is also a very important area on the emission of
odours (sub-tail glands produce musk). Behaviour studies suggest that smell
is very important in the sensorial world of this species, namely in
communication. 
A specialised enterprise on animal radio monitoring proposed us an
alternative to the use of tailmounts attached with a cable-ties: the
transmitters can be glued on the rump. The weight of these tags is 2,5
grams but the adhesive also contributes to the mass of the transmitter
package.

How does the natural behaviour become influenced by the attached tag (with
cable-ties or glued)? 

Pyrenean desman has long and dense fur and probably it may be clipped to
have a successful attachment. Oiliness, that is very abundant is this
species, may have also a negative influence. 
Behaviour studies show that grooming is a very important activity in this
species: it contributes to maintain fur in a good condition; different
postures ensure that all the body part was groomed. It seems perfectly
predictable that the animals can use their hind feet to pull off the tag.
Desmans spend most of their activity time in water, searching for food
(freshwater invertebrates) in the bottom of the river bed. We might use a
very powerful and non-water soluble glue. 

How long can the attachment be maintained?

Another specialised enterprise on animal radio monitoring proposed us
another alternative: transmitters designed for intraperitoneal
implantation, equipped with a helical antenna. The weight of these
transmitters is 1,8 grams. 
This kind of transmitters was used by Russian researchers (ONUFRIENJA &
ONUFRIENJA, 1993) in the study of Desmana moschata. Despite our
non-experience in surgery, handling and husbandry Galemys is much more
complicated: the species is smaller and less tolerant to artificial
captivity conditions (QUEIROZ, 1996). Mortality in the surgical and
recuperation procedures might be avoided. 
Implanted transmitters give comparatively a poor range, which is even more
complicated when the followed animal inhabits a very structured habitat, it
walks, it swims, it dives and it rests in natural hollows.

What is the best? Implanted or not implanted transmitters ?

These are some of the question we discuss now. If someone have experience
on: (1) radio-tracking with small mammals (e.g. shrews, moles, voles); (2)
radio-tracking with aquatic animals (e.g. mammals, birds, amphibians or
fishes); (3) know how on intraperitoneal implantation or other surgical
procedures in sensitive animals (e.g. those that have very high metabolic
rates); we would like to received your suggestions. 

Contact us:
e-mail: carlos.romao. at mail.telepac.pt
or
Ana Isabel Queiroz
Instituto da Conservagco da Natureza
Rua Filipe Folque, n: 46 - 1:
P-1050 LISBOA - Portugal
FAX: +351 - 1 - 3574771

ONUFRIENJA & ONUFRIENJA (1993) Desman in Oka State Reserve (Russia).
Proceedings of the Meeting on the Pyrenean Desman. Sept.1992, Lisboa,
Portugal.

QUEIROZ, (1996) [ On the behavior of desmans, Galemys pyrenaicus Geoffroy
and Desmana moschata L. ] Sobre o comportamento das toupeiras-de-agua,
Galemys pyrenaicus Geoffroy and Desmana moschata L.. Master thesis in
Ethology. ISPA, Lisboa. 89 pp.

Stone (1985) Home range movements of Pyrenean Desman (Galemys pyrenaicus)
(Insectivora: Talpidae). Zeitschrift fur angewandte zoologie: 25-36






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