Mammals in MZNA-VERT: project Loza

Study Extent

Loza Lagoon is situated in Pamplona’s Basin in the centre of Navarra (Spain). Lagoons play an important role in biodiversity conservation as they constitute a stopover for migrants’ birds. Lagoons in Navarra are mainly located in the south whereas Loza is one of the most northern lagoons in Navarra. Land cover in Loza is characterised by prairies, scrubland, reed bed patches and some black poplar as well. Crops and pine repopulations enclose the lagoon (Arizaga et al, 2009).

Sampling

Sampling was conducted between February and October in 2007. Sherman traps (7,5x9x23 cm) were placed along a habitat gradient varying from pastures to scrubland following a transect. The distance between traps was approximately 10 metres. Only half of the traps were baited in order to avoid bias due to the baiting. Each sampling event consisted on four nights. Traps were placed first night and checked for animals the four days after. The total sampling effort made was 800 traps per night. Specimens were sexed, identified in field using external morphology and then released. In addition few barn owl pellets were collected within the study area during the sampling period for completing the sampling.

Quality Control

All specimens collected in the field are deposited in the Museum of Zoology of the University of Navarra (MZNA, Pamplona, Spain) in the ‘Project Loza’ collection. All the species were sexed and identified in field by Carmen Escala and David Galicia. Specimens from pellets were identified using suitable literature (Gosálbez 1987). Scientific names were validated according to Mammal Species of the World (Wilson and Reeder 2005, Palomo et al. 2007). Coordinates in UTM/MGRS were transformed to geographic system. The consistency of all records was checked by visual inspection overlapping coordinates with a Navarra map using GIS (Chapman 2005) and their uncertainty was calculated in metres using the point-radius method.

Method steps

1. Barn owl pellets were frozen at -20ºC for removing bugs. After that, pellets were dissected and skulls, mandibles and other bones were separated for taxonomic identification. Specimens were identified using a stereoscopic microscope and appropriate literature (Gosálbez 1987). Finally, specimens were placed in plastic bags with their unique catalogue number and stored in the museum facilities. Specimens found dead were transported to laboratory where the skull was prepared. First, specimens were dissected separating skull and axial skeleton from the rest of the body. Then, they were boiled and flesh was removed from the bones. Once dried, they were placed in zip plastic bags with their unique catalogue number. From some specimens following measures were obtained: body length, tail length, ear length and hind foot length. Information about specimens and occurrence was incorporated to MZNA database (Zootron v4.5, Ariño 1991).

Specimens were identified to species level in field using external morphology. The collection is composed of orders Carnivora, Rodentia and Soricomorpha, 4 families and 8 species although the order Carnivora is represented by only 3 records of Mustela nivalis. Muridae is the most abundant family followed by Soricidae and Cricetidae. The most abundance species is Apodemus sylvaticus (181 records).

1. Animalia
   rank: kingdom
2. Chordata
   rank: phylum
3. Mammalia
   rank: class
4. Carnivora
   rank: order
5. Rodentia
   rank: order
6. Soricomorpha
   rank: order
7. Cricetidae
   rank: family
8. Muridae
   rank: family
9. Mustelidae
   rank: family
10. Soricidae
    rank: family
11. Apodemus
    rank: genus
12. Crocidura
    rank: genus
13. Microtus
    rank: genus
14. Mus
    rank: genus
15. Mustela
    rank: genus
16. Neomys
    rank: genus
17. Sorex
    rank: genus
18. Apodemus sylvaticus
    common name: Long-tailed field mouse rank: species
19. Crocidura russula
    common name: Greater white-toothed shrew rank: species
20. Microtus agrestis
    common name: Field vole rank: species
21. Microtus duodecimcostatus
    common name: Mediterranean pine vole rank: species
22. Mus spretus
    common name: Western mediterranean mouse rank: species
23. Mustela nivalis
    common name: Least weasel rank: species
24. Neomys fodiens
    common name: Eurasian water shrew rank: species
25. Sorex coronatus
    common name: Millet's shrew rank: species

The project was conducted in Loza Lagoon and all occurrences and specimens come from the surrounding area near the lagoon.