| 1. |
- Fraixedas, Sara, et al.
(author)
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Substantial decline of Northern European peatland bird populations : Consequences of drainage
- 2017
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In: Biological Conservation. - : Elsevier BV. - 0006-3207. ; 214, s. 223-232
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Journal article (peer-reviewed)abstract
- Northern European peatlands are important habitats for biological conservation because they support rich biodiversity and unique species compositions. However, historical management of peatland habitats has had negative consequences for biodiversity and their degradation remains a major conservation concern. Despite increasing awareness of the conservation value of peatlands, the statuses and ecological requirements of peatland species have remained largely understudied. Here, we first analysed temporal trends of Northern European peatland birds to document the status of their populations using bird data from five different countries. Second, we used Finnish monitoring data to assess habitat preferences of peatland bird species, hence helping to target conservation to the most relevant habitat types. There was a general decline of 40% in Northern European peatland bird population sizes in 1981–2014 (speed of decline 1.5%/year) largely driven by Finland, where populations declined almost 50% (2.0% annual decline). In Sweden and Norway, peatland bird populations declined by 20% during 1997–2014 (1.0% annual decline). In contrast, southern populations in Estonia and Latvia, where the majority of open peatlands are protected, showed a 40% increase during 1981–2014 (1.0% annual increase). The most important habitat characteristics preferred by common peatland species in Finland were openness and low tree height, while wetness proved to be an important feature for waders. Drainage of peatlands had clear negative effects on the densities of many species, with the only exception of rustic bunting, which specializes on edge habitats. Our findings call for more effective conservation actions in Northern European peatland habitats, especially in Finland where peatland drainage represents a major threat to biodiversity.
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| 2. |
- Herrmann, Christof, et al.
(author)
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Population Development of Baltic Bird Species : Great Cormorant (Phalacrocorax carbo sinensis)
- 2019
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Other publication (other academic/artistic)abstract
- During the 19th century, the Great Cormorant was exterminated as a breeding bird in several Baltic countries. The persecution continued until the mid of the 20th century, and in the early 1960s the European breeding population of the continental subspecies sinensis had declined to 4,000 breeding pairs (bp) only, of which Germany and Poland hosted more than the half. During the following two decades, the population development apparently has also been affected by the harmful effects of DDT and PCB.As a result of protection measures, and seemingly also due to the ban of DDT and PCB, breeding pair numbers started to increase during the second half of the 1970s. During the 1980s, the Cormorant started to expand its range towards the northern and eastern parts of the Baltic. Currently, the species is present in the whole Baltic Sea area, including the northern parts of the Gulf of Bothnia.Baltic-wide surveys in 2006, 2009 and 2012 showed that the Baltic population had stabilized at a level of 155,000 – 170,000 bp during that period. However, after 2012 breeding pair numbers have still increased in the eastern and northern Baltic. Hence, the current population is estimated at 190,000-210,000 bp.The highest population densities are found around the highly eutrophic estuaries of the southern Baltic (Odra-, Vistula-, and Curonian lagoon).
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| 3. |
- Ojaste, Ivar, et al.
(author)
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From northern Europe to Ethiopia : Long-distance migration of Common Cranes (Grus grus)
- 2020
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In: Ornis Fennica. - 0030-5685. ; 97:1, s. 12-25
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Journal article (peer-reviewed)abstract
- The majority of Common Cranes (Grus grus) breeding in northern Europe are short- to medium-distance migrants that overwinter in southern Europe, northern Africa, and the Middle East. However, some individuals migrate longer distances to as far as Ethiopia. Using data from 18 satellite-tracked juvenile Common Cranes, we assessed (1) the length and landscape composition of the migratory routes used and (2) the behaviour of neighbouring Finnish and Estonian (500 km apart in the north-south direction) sub-populations. Our results show that Common Cranes mainly use the East European flyway to reach the wintering grounds in Ethiopia, yet some individual cranes may alternatively use the Baltic-Hungarian migration route. Neither duration nor the number of stopovers used influenced the flight distances of the cranes. Further, 7-19 days of refuelling enabled the cranes to cover long flight distances, from 2,420 to 5,110 km in 6-15 days, without the need for settling down at potential stopovers on the route. Contrary to our expectations, the main refuelling sites of the Finnish breeding population were further south (in southern Ukraine) than those of the Estonian population (in Belarus). Despite the longer flight distances, Finnish cranes used three main migration stages, while cranes breeding at more southern sites generally used mainly four stages. Our findings demonstrate that large-sized social migrants such as the Common Crane may have spatially segregated, flexible migration patterns that involve only a few carefully selected stopovers during long-distance migration.
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