| 1. |
- Dessborn, Lisa, et al.
(författare)
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Geese as vectors of nitrogen and phosphorus to freshwater systems
- 2016
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Ingår i: INLAND WATERS. - 2044-2041 .- 2044-205X. ; 6:1, s. 111-122
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Tidskriftsartikel (refereegranskat)abstract
- Many goose populations have increased dramatically over the past decades, which may influence inland waters used as roost sites. We reviewed the role of geese in the influx of nitrogen and phosphorus to freshwater systems. Several methods have been used to estimate guanotrophication impacts of geese. Water and sediment analysis have been conducted in areas of high and low geese presence; however, productive wetlands tend to attract more birds, and the causality is therefore ambiguous. Faecal addition experiments have attempted to estimate the impacts of droppings on water chemistry, sediments, algal growth, or invertebrate densities. The most common method of estimating goose guanotrophication is by extrapolation, usually based on multiplication of faecal production and its nutrient content. Based on such studies and those including information about daily migration patterns, we developed an approach to improve estimates of the nutrient contribution of geese. The relative role of geese in wetland eutrophication is also affected by the influx from alternative sources. The greatest guanotrophication impacts are likely found in areas with few alternative nutrient sources and with large goose flocks. Limited inflow and outflow of a freshwater system or a scarcity of wetland roosts may also increase problems at a local scale. Although several studies have looked at the impacts of geese on, for example, water chemistry or soil sediments, the effects are often smaller than expected, in part because no study to date has assessed the ecosystem response by including impacts on all levels, including water nutrient levels, nutrient sedimentation, chlorophyll content, and zooplankton response.
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| 2. |
- Elmberg, Johan, 1960-
(författare)
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Goose poop in the park
- 2018
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Ingår i: Bottom Line Health. - 1092-0129. ; 32:6
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Elmberg, Johan, 1960-, et al.
(författare)
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Passage patterns of seabirds in October at Cabo Carvoeiro Portugal, with special reference to the Balearic Shearwater Puffinus mauretanicus
- 2016
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Ingår i: Marine Ornithology. - 1018-3337 .- 2074-1235. ; 44:2, s. 151-156
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Tidskriftsartikel (refereegranskat)abstract
- Land-based counts of migrating seabirds remain essential to increase knowledge about their numbers and movements. To assess the value of Cabo Carvoeiro (Peniche, Portugal) as a monitoring site in the East Atlantic, we studied seabird species composition, passage patterns and flock size during mid-October 2014. During standardized counts, we observed nearly 8 000 seabirds of 17 species. The ratio of individuals passing in a southerly to southwesterly direction was >96% in all species, showing that genuine migrants were counted. The passage rate (birds/hour) was higher for Northern Gannets Morus bassanus than for any other species, by a factor of approximately 50 (morning mean 906/h, afternoon mean 1 153/h). The globally endangered Balearic Shearwaters Puffinus mauretanicus, Great Skuas Stercorarius skua and Pomarine Skuas S. pomarinus had passage rates of 10–25/h. Flock size distribution in the 11 most numerous species showed that most migrated singly or in groups of two. Flock size was larger in Balearic Shearwaters than in both Cory’s Calonectris borealis and Manx Shearwaters P. puffinus. Among skuas, flock size was larger in Pomarine than in Great Skuas. The passage rate of Manx Shearwaters was positively correlated with that of Northern Gannets, Great Skuas and Sandwich Terns Sterna sandvicensis. Northern Gannets showed a positive co-variation with Pomarine Skuas. Balearic and Sooty Shearwaters Ardenna griseus were the only species that did not show any significant co-variation with another species. Morning and afternoon passage rates did not differ significantly in any of the six most numerous species (Northern Gannets, Cory’s and Balearic Shearwaters, Great and Pomarine Skuas, and Sandwich Terns), or in Sooty Shearwaters (less numerous). Thus, the passage rates at Cabo Carvoeiro in October of Balearic Shearwaters and five other species were as high or higher than those reported from any other seawatch in Portugal, indicating the international value of seabird monitoring at Cabo Carvoeiro during the autumn migration.
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| 4. |
- Elmberg, Johan, 1960-, et al.
(författare)
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Population change in breeding boreal waterbirds in a 25‐year perspective : what characterises winners and losers?
- 2019
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Ingår i: Freshwater Biology. - : Wiley: 12 months. - 0046-5070 .- 1365-2427. ; 65:2, s. 167-177
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Tidskriftsartikel (refereegranskat)abstract
- Understanding drivers of variation and trends in biodiversity change is a general scientific challenge, but also crucial for conservation and management. Previous research shows that patterns of increase and decrease are not always consistent at different spatial scales, calling for approaches combining the latter. We here explore the idea that functional traits of species may help explaining divergent population trends.Complementing a previous community level study, we here analyse data about breeding waterbirds on 58 wetlands in boreal Fennoscandia, covering gradients in latitude as well as trophic status. We used linear mixed models to address how change in local abundance over 25 years in 25 waterbird species are associated with life history traits, diet, distribution, breeding phenology, and habitat affinity.Mean abundance increased in 10 species from 1990/1991 to 2016, whereas it decreased in 15 species. Local population increases were associated with species that are early breeders and have small clutches, an affinity for luxurious wetlands, an herbivorous diet, and a wide breeding range rather than a southern distribution. Local decreases, by contrast, were associated with species having large clutches and invertivorous diet, as well as being late breeders and less confined to luxurious wetlands. The three species occurring on the highest number of wetlands all decreased in mean abundance.The fact that early breeders have done better than late fits well with previous research about adaptability to climate change, that is, response to earlier springs. We found only limited support for the idea that life history traits are good predictors of wetland level population change. Instead, diet turned out to be a strong candidate for an important driver of population change, as supported by a general decrease of invertivores and a concomitant increase of large herbivores.In a wider perspective, future research needs to address whether population growth of large‐bodied aquatic herbivores affects abundance of co‐occurring invertivorous species, and if so, if this is due to habitat alteration, or to interference or exploitative competition.
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| 5. |
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| 6. |
- Elmberg, Johan, 1960-, et al.
(författare)
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Utsatta änder inte som vilda
- 2018
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Ingår i: Svensk Jakt. ; :10, s. 51-51
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 7. |
- Holopainen, Sari, et al.
(författare)
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Sustainable management of migratory European ducks : finding model species
- 2018
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Ingår i: Wildlife Biology. - : Nordic Council for Wildlife Research (NKV). - 0909-6396 .- 1903-220X.
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Tidskriftsartikel (refereegranskat)abstract
- Eurasian migratory duck species represent a natural resource shared between European countries. As is evident throughout human harvest history, lack of coordinated management and monitoring at appropriate levels often leads to ‘the tragedy of the commons’, where shared populations suffer overexploitation. Effective management can also be hampered by poor understanding of the factors that limit and regulate migratory populations throughout their flyways, and over time. Following decades of population increase, some European duck populations now show signs of levelling off or even decline, underlining the need for more active and effective management. In Europe, the existing mechanisms for delivering effective management of duck populations are limited, despite the need and enthusiasm for establishing adaptive management (AM) schemes for wildlife populations. Existing international legal agreements already oblige European countries to sustainably manage migratory waterbirds. Although the lack of coordinated demographic and hunting data remains a challenge to sustainable management planning, AM provides a robust decision-making framework even in the presence of uncertainty regarding demographic and other information. In this paper we investigate the research and monitoring needs in Europe to successfully apply AM to ducks, and search for possible model species, focusing on freshwater species (in contrast to sea duck species) in the East Atlantic flyway. Based on current knowledge, we suggest that common teal Anas crecca, Eurasian wigeon Mareca penelope and common goldeneye Bucephala clangula represent the best species for testing the application of an AM modelling approach to duck populations in Europe. Applying AM to huntable species with relatively good population data as models for broader implementation represents a cost effect to develop AM on a European flyway scale for ducks, and potentially other waterbirds in the future.
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| 8. |
- Pöysä, Hannu, et al.
(författare)
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Changes in species richness and composition of boreal waterbird communities : a comparison between two time periods 25 years apart
- 2019
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Ingår i: Scientific Reports. - : Nature Publishing Group: Open Access Journals - Option C / Nature Publishing Group. - 2045-2322. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Global measures of biodiversity indicate consistent decline, but trends reported for local communitiesare more varied. Therefore, we need better understanding of mechanisms that drive changes in diversity of local communities and of differences in temporal trends between components of local diversity, such as species richness and species turnover rate. Freshwater ecosystems are vulnerable to multiple stressors, and severe impacts on their biodiversity have been documented. We studied species richness and composition of local boreal waterbird communities in 1990/1991 and 2016 at 58 lakes distributed over six regions in Finland and Sweden. The study lakes represented not only local trophic gradients but also a latitudinal gradient in the boreal biome. While species richness tended to be lower in 2016 than in 1990/1991, species turnover was relatively high. Within foraging guilds, local species richness of diving ducks and surface feeding waterbirds decreased, whereas that of large herbivores increased. The number of species gained in local communities was higher in lakes with rich vegetation than in lakes with sparse vegetation. Conservation of boreal freshwater ecosystems would benefit from recognizing hat large-scale environmental changes can affect local diversity via processes operating atfiner scales.
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| 9. |
- Pöysä, Hannu, et al.
(författare)
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Habitat associations and habitat change : seeking explanation for population decline in breeding Eurasian wigeon Anas penelope
- 2017
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Ingår i: Hydrobiologia. - : Springer Verlag (Germany). - 0018-8158 .- 1573-5117. ; 785:1, s. 207-217
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Tidskriftsartikel (refereegranskat)abstract
- We explored whether the recent large-scale population decline of Eurasian wigeon (Anas penelope) in Europe may be linked to long-term vegetation changes in their boreal breeding wetlands. First, we assessed the importance of Equisetum, Phragmites, and Carex stands in lake selection by pairs and in foraging habitat selection by broods. Second, in 2013–2014 we revisited 58 lakes in Sweden and Finland studied in 1990–1991, to examine if there had been any long-term change in the abundance of habitat types preferred by wigeon. Finally, using continuous long-term data on breeding numbers of wigeon in 18 of the lakes studied in 1990–1991, we examined if wigeon numbers had changed at lakes where the habitat also had changed. We found that lake occupation of nesting wigeon pairs and foraging habitat use of broods were associated with the extent of Equisetum stands. The presence and abundance of this preferred habitat declined dramatically from 1990–1991 to 2013–2014 in the lakes from which the presence–absence data of wigeon emanate. Breeding numbers of wigeon showed a long-term declining trend in lakes where Equisetum has decreased. Our results imply that the recent population decline of wigeon in Europe may be linked to decrease of Equisetum habitat.
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