Portal to the Lesser White-fronted Goose

Literature type: Thesis

Language: English

External Link:

Full reference: Markkola, J. 2022. Ecology and conservation of the Lesser White-fronted Goose Anser erythropus. , PhD thesis, Acta Universitatis Ouluensis. A Scientiae Rerum Naturalium 770. Faculty of Science, University of Oulu, Finland.

Keywords: spring arrival, Anser erythropus, Anser fabalis, breeding schedule, habitat, diet selection, meadow management, population genetic structure, Finland

Abstract:

I studied the rare and threatened lesser white-fronted goose (Anser erythropus), abbreviated LWfG in 1989–1996 in sub-arctic Finnish Lapland (I). The studied subpopulation consisted of 2–15 breeding pairs annually. A total of 30 broods were observed with an average of 2.9 goslings per brood. The 1st year survival of tagged 10 geese was low. Satellite locations, recoveries and resightings were received from NW Russia, Kazakhstan and the Azov Sea area. Cold spells had a negative, and the sum of effective temperatures by 5 July a positive influence on reproduction. Habitat selection (II) was studied in the same area. LWfG preferred the vicinity of water, flat close-range landscape, low forest height and intermediate relative altitudes. LWfG aggregated in the vicinity of conspecifics within the preferred habitats. The averaged RSF model assigned observation and random points correctly with 83.4% success. Locations of historical observations of LWfG matched the predicted distribution of breeding sites. (III) Spring migration patterns on the Bothnian Bay coast of LWfG were examined in 1907–1916 and 1949–2014 and the taiga bean goose (Anser fabalis fabalis) in 1975–2014. Arrival of the short-distance migrant A. fabalis advanced more and earlier than the long-distance migrant A. erythropus, 10.9 days since late 1980’s vs. 5.3 days since the beginning of the 2000’s. In the LWfG, the best model for explaining variation in timing included global and local temperatures, in A. fabalis global and local temperatures and winter NAO. Increasing global temperatures seem to explain trends in both. In the spring staging places of the Bothnian Bay almost all dietary items of the LWfG were Monocotyledons, mostly grasses growing in extensive sea-shore meadows (IV). Only Phragmites, Festuca and possibly Triglochin palustris were preferred. Lesser White-fronts preferred extensive natural meadows. Mowing and grazing benefit the restoration of habitats. Genetic structuring of the LWfG was examined in its whole distribution area from Fennoscandia to East Asia (V). A fragment of the control region of mtDNA was sequenced from 110 individuals. 15 mtDNA haplotypes were assigned to two mtDNA lineages. Molecular variance showed significant structuring among populations: the main western in north-western Russia – Central Siberia, the main eastern in East Asia and the Nordic one, which earns a status as an independent management unit.

Literature type: Scientific

Journal: Bird Conservation International

Volume: 27 , Pages: 355-370.

DOI: 10.1017/S0959270916000393

Language: English

Full reference: Karmiris, I., Kazantzidis, S., Platis, P. & Papachristou, T.G. 2017. Diet selection by wintering Lesser White-fronted Goose Anser erythropus and the role of food availability. Bird Conservation International 27: 355-370. https://www.dx.doi.org/10.1017/S0959270916000393

Keywords: diet selection, food availability, diet composition, droppings, protein, Kerkini Lake, Echinochloa crus-galli, Cyperus esculentus, Scirpus lacustris, Ranunculus sceleratus

Abstract:

The Fennoscandian population of the Lesser White-fronted Goose Anser erythropus (LWfG) is on the verge of extinction and migrates from northern Fennoscandia to Greece on a regular seasonal basis. For the first time, diet selection was investigated during two years at Kerkini Lake, a wintering site in Greece. The relative use of LWfG’s feeding habitats was systematically recorded by visual observations of the LWfG flocks. Food availability was measured by the relative cover of available vegetation types while the diet composition was determined by the microhistological analysis of droppings. In addition, we determined crude protein, neutral detergent fibre, acid detergent fibre and acid detergent lignin content of the most preferred plant species by LWfG and all vegetation categories that contributed to LWfG diet in the middle of the duration of their stay at Kerkini Lake and after their departure from the lake. LWfG feeding habitat was exclusively marshy grassland in water less than 5 cm deep up to 300–400 m away from the shore. LWfG selected a diverse number of plant species (33), however, grass made up the 58% of their diets. The most preferred plant species were Echinochloa crus-galli, Cyperus esculentus, Scirpus lacustris and Ranunculus sceleratus. LWfG departed from Kerkini Lake in mid-December to the Evros Delta (Thrace, eastern Greece), when either food availability falls in very low levels or flooding occurred in their main feeding habitat. Consequently, as long as food and habitat resources are available for LWfG, it is very likely that the birds will winter mainly at Kerkini Lake and not at the Evros Delta, which will contribute to further minimisation of the theoretical risk of accidental shooting of LWfG at the latter wintering habitat. Thus, future conservation actions should primarily focus on the grassland improvement at Kerkini Lake enhancing the availability of food resources for LWfG (mainly grasses) and the protection of the feeding habitat from flooding.

Literature type: Scientific

Journal: Ecography

Volume: 26 , Pages: 705-714.

DOI: 10.1111/j.0906-7590.2003.03576.x

Language: English

Full reference: Markkola, J., Niemela, M., & Rytkonen, S. 2003. Diet selection of lesser white-fronted geese Anser erythropus at a spring staging-area. Ecography 26: 705-714. https://www.dx.doi.org/10.1111/j.0906-7590.2003.03576.x

Keywords: diett, spring staging

Abstract:

We studied diet selection of the globally threatened lesser white-fronted goose Anser eythropus at a spring staging area on the island of Hailuoto (64°00′N, 24°45′E), off the western coast of Finland. We determined the diet using droppings, which were collected in late May, when the geese had left the area and migrated northwards. The sample potentially comprised of ejecta from 31 different individuals. Plant idengification was based on visual determination of epidermal fragments. A total of 100 droppings were sampled using a point quadrat method. We calculated the percentage of each idengified taxon in each dropping and related this to the availability of the corresponding taxon in the meadow. We measured preference for each taxon using Chesson's electivity index (ɛi) and tested them by bootstrap resampling. The diet contained 9 taxa of the ca 40 available. Almost all dietary items were Monocotyledons (99.9%), mostly grasses (88.7%) including Festuca rubra (43%), Phragmites australis (30%) and Calamagrostis stricta (13%). Only Phragmites (ɛ=0.73, p=0.000), Festuca (ɛ=0.52, p=0.004) and possibly Triglochin palustris (ɛ=0.70, p=0.125) were preferred, all other species were avoided. All preferred species were quite common and other goose species exploit them too. The lesser white-fronted geese preferred large natural meadows that were five times broader than an “average” Bothnian Bay meadow. All forms of mowing and grazing management benefit the restoration of lesser white-fronted goose habitats at the landscape level. Festuca and especially Triglochin benefit from such management. Reeds, Phragmites, whose spread has been the main cause of coastal meadow deterioration, can be controlled by management, but can also be maintained among other vegetation if mowing is less frequent or grazing not too intensive.