Clausen, P. & Pedersen, C.L. 2021. Vurdering af konsekvenser for vandfugle ved eventuelle justeringer af reservaterne i fuglebeskyttelsesområde nr. 15. Mariager og Sødring Vildtreservater. Aarhus Universitet, DCE – Nationalt Center for Miljø og Energi, 44 s. - Teknisk rapport nr. 216. http://dce2.au.dk/pub/TR216.pdf
The Mariager Fjord and Sødring Game Reserves (designated in 1996 and 1999, respectively) are situated within the Randers and Mariager Fjords and Ålborg Bay (southern part) Special Protection Area (SPA No. 15). There are specific restrictions on hunting within both of these reserves, especially within the intertidal area, and limited public access on small islands and islets used by nesting birds during their breeding season. As the two reserve executive orders have not been revised since the reserves were established in the 1990s, the Danish Environmental Protection Agency, in consultation with the Wildlife Management Council's Reserve Group, has initiated a review of the reserve regulations within the SPA.
Since the 1990s, there have been major redistributions of submerged aquatic plants, especially in Mariager Fjord. As a result, the abundance and distribution of herbivorous waterbirds such as Mute Swan Cygnus olor, Light-bellied Brent Goose Branta bernicla hrota, several species of dabbling ducks and Eurasian Coot (hereafter Coot) Fulica atra within the reserves have changed. All these species have declined in number, while the Coot has largely disappeared from the area. The same applies to the number and distribution of colony-nesting species such as Pied Avocet Recurvirostra avosetta and four species of terns, all of which have occurred in greater numbers in the past. This report provides a updated status of the abundance and distribution of the these waterbird species.
The report focusses on the abundance and distribution of staging and wintering herbivorous waterfowl reported during the entire hunting season from September to January, with additional descriptions of changes in the numbers of distribution of moulting Mute Swan in the area. The distribution of the herbivores is also compared with the mapped distribution of submerged macrophytes in the outer part of Mariager Fjord, where there used to be widespread and dense submerged vegetation. The focus on colony-nesting coastal birds is on their distribution during the nesting season.
The Danish Environmental Protection Agency has asked DCE (Danish Centre For Environment And Energy) to review five proposals for changes to the current reserve regulations for the two reserve. Three of these relate to traffic and hunting restrictions in relation to staging and wintering waterbirds, while two are about designating new areas with bans on traffic and human access during the breeding season.
Based on the available data and taking into account the original objectives set for the reserves (i.e. protection of the particularly disturbance-sensitive huntable species of geese and dabbling ducks), it is recommended that there be no significant changes made to the current protection of Ajstrup Bay and the area east of the Overgaarddiget. In the latter area, a ban on sailboarding will ensure further protection for foraging and resting birds. An adjustment of the protected area to the east in Ajstrup Bay might make the reserve boundary more easily recognizable in the field, e.g. for hunters and others active in the area, but would at the same time open for hunting in one of the most important areas for dabbling ducks in Mariager Fjord.
Taking into account the declining numbers of moulting Mute Swans using the area, one should consider whether the existing ban on windsurfing during autumn, winter and spring should be extended to include the summer.
Along the stretch of coast from Als Odde to Øster Hurup, a hunting-free reserve is designated within a 100 metre zone from the shore in areas that have the status of a summer house area and within a 500 metre zone from designated urban areas. As this area currently constitutes the most important area for foraging light-bellied brent geese, it should be considered whether an enlargement of this regulation and taking into account the current distribution of aquatic plants and redistribution of herbivorous waterfowl, will be beneficial to herbivorous waterbirds within the entire SPA.
For breeding birds, two proposals for a ban on traffic during the breeding season entering into the reefs and small islands northeast of Als Odde and on Odpold in Randers Fjord should improve opportunities for colony-nesting Pied Avocets and terns to breed successfully within the SPA.
The saltmarshes at Odpold, a former breeding site for Pied Avocets and Baltic Dunlin Calidris alpine schinzii, are now overgrown. Before the species can be attracted back to the area as a regular breeding site, regulation of human access will need to be implemented together with an active nature conservation effort to restore short sward saltmarshes. This could be achieved ideally through grazing or alternatively cutting for hay, to counteract the current overgrown vegetation. The area also seems suitable for fencing off from potential mammalian predators, which could potentially promote the possibility of restoring breeding populations of Pied Avocet and perhaps even attract dunlins and terns as breeding birds at the site. Suitable management of the saltmarshes will also make the site more attractive to foraging Light-bellied Brent Geese, which back in the 1990s frequently used the area, but now no longer do so.
