| 1. |
- Strong, Emily A., et al.
(författare)
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Seeking greener pastures : crop selection by Greylag Geese (Anser anser) during the moulting season
- 2021
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Ingår i: Ornis Fennica. - : Finnish Omithological Soc. - 0030-5685. ; 98:1, s. 16-32
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Tidskriftsartikel (refereegranskat)abstract
- Over the last 40 years, many goose populations have recovered from historic lows and are now more numerous than ever. At the same time, geese have shifted from natural foraging habitats to securing most of their nutritional demands from agricultural fields, leading to crop damage and conflict with agriculture. We studied field use by Greylag Geese (Anser anser) in the agricultural landscape surrounding a main breeding and moulting lake in Sweden. From 2012 to 2016, weekly roadside surveys were conducted from May to July. Data were collected on goose numbers, crop type and sward height in agricultural fields. Using a compositional analysis, we demonstrate that Greylag Geese show a strong selection for ley and pasture fields compared to other crop types (rank order: ley/pasture > oat > barley > wheat > other crops). This selection was consistent across years and between pre- and post-moult. Aside from ley and pasture, no other croptypes were selected for, as they were used less than expected given their availability. Irrespective of crop type, geese foraged predominantly on short (0–10 cm) swards. The strong selection for ley and pasture may have been driven by higher nutritional quality of short, managed grass swards relative to other available foods. This suggests that during the summer grass fields may be more vulnerable to damage compared to other crop types. Our study provides a deeper understanding of the ecology of Greylag Geese, which may be used to inform management strategies focused on mitigating crop damage and alleviating conflict.
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| 2. |
- Dessborn, Lisa, 1976-, et al.
(författare)
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Hatching in dabbling ducks and emergence in chironomids : a case of predator-prey synchrony?
- 2009
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Ingår i: Hydrobiologia. - : Springer Verlag (Germany). - 0018-8158 .- 1573-5117. - 0018-8158 ; 636:1, s. 319-329
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Tidskriftsartikel (refereegranskat)abstract
- It has been hypothesized that dabbling ducks (Anas spp.) time breeding to coincide with annual regional peaks in emerging dipterans, especially Chironomidae, which are important prey for newly hatched ducklings. However, this hypothesis has never been evaluated in a replicated lake-level study, including year effects in emergence patterns. We collected duck and invertebrate data from 12 lakes during the nesting seasons 1989-1994 in a watershed in southern Finland. The oligotrophic study lakes are typical of the boreal Holarctic, as are the three focal duck species: mallard Anas platyrhynchos L., widgeon Anas penelope L and teal Anas crecca L. Hatching of ducklings showed a clear peak in relation to ambient phenology (annual ice-out date of lakes), whereas chironomid emergence was more erratic and showed no clear peak at the lake level, although total watershed-level emergence was somewhat higher before and long after the duck hatching peak. Thus, we find no evidence that ducklings hatch in synchrony with abundance peaks of emerging chironomids. There was large within-year temporal variation in chironomid emergence among lakes, but this was not correlated with ambient temperature. The rank of individual lakes with respect to the abundance of emerging chironomids was consistent among as well as within years, a predictability that ought to make adaptive lake choice by ducks possible. On the lake level, there was a positive correlation between the total amount of emerging chironomids and brood use. We argue that emergence patterns of chironomids on typical boreal lakes are neither compressed nor predictable enough to be a major selective force on the timing of egg-laying and hatching in dabbling ducks. Despite spatial (among-lake) patterns of abundance of emerging chironomids being predictable within and among years, the observed pattern of brood use suggests that other factors, e.g. habitat structure, also affect lake choice.
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| 3. |
- 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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| 4. |
- Hultberg, M, et al.
(författare)
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Fungi-based treatment of real brewery waste streams and its effects on water quality
- 2019
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Ingår i: Bioprocess and biosystems engineering (Print). - : Springer Verlag (Germany). - 1615-7591 .- 1615-7605. ; 42:8, s. 1317-1324
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Tidskriftsartikel (refereegranskat)abstract
- Nutrient-rich liquid waste streams generated during the beer brewing were treated by submerged fungal growth. Among five filamentous fungal strains tested, Pleurotus ostreatus and Trichoderma harzianum were selected for treatment of run-off from spent grain and hot trub, respectively. In both waste streams, nitrogen was well removed by fungal treatment, with a maximum reduction of 91.5 ± 0.5% of total nitrogen in run-off from spent grain treated with P. ostreatus and 77.0 ± 3.1% in hot trub treated with T. harzianum. Removal of phosphorus was considerably lower, with maximum removal of total phosphorus of 30.8 ± 11.1% for the P. ostreatus treatment and 16.6 ± 7.8% for the T. harzianum treatment. Considering the high concentration of phosphorus in the waste sources (320-600 mg L-1), additional techniques for its removal are needed. In the P. ostreatus treatment, a total amount of 13.2 ± 2.2 g L-1 dwt of biomass with a protein concentration of 11.6 ± 2.1% was produced.
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| 5. |
- Lundberg, Per, et al.
(författare)
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Viltpopulationer och deras dynamik
- 2010
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Ingår i: Vilt, människa, samhälle. - Stockholm : Liber. - 9789147094189 ; , s. 53-79
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Bokkapitel (populärvet., debatt m.m.)
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| 6. |
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| 7. |
- Arzel, Céline, et al.
(författare)
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Early springs and breeding performance in two sympatric duck species with different migration strategies
- 2014
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Ingår i: Ibis. - : Wiley: 12 months. - 0019-1019 .- 1474-919X. ; 156:2, s. 288-298
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Tidskriftsartikel (refereegranskat)abstract
- The capacity of migratory species to adapt to climate change may depend on their migratory and reproductive strategies. For example, reproductive output is likely to be influenced by how well migration and nesting are timed to temporal patterns of food abundance, or by temperature variations during the brood rearing phase. Based on two decades (1988–2009) of waterfowl counts from a boreal catchment in southern Finland we assessed how variation in ice break-up date affected nesting phenology and breeding success in two sympatric duck species, Mallard Anas platyrhynchos and Eurasian Teal Anas crecca. In Fennoscandia these species have similar breeding habitat requirements but differ in migration distance; Teal migrate roughly seven times as far as do Mallard. Annual ice break-up date was used as a proxy of spring ‘earliness’ to test the potential effect of climate change on hatching timing and breeding performance. Both species were capable of adapting their nesting phenology, and bred earlier in years when spring was early. However, the interval from ice break-up to hatching tended to be longer in early springs in both species, so that broods hatched relatively later than in late springs. Ice break-up date did not appear to influence annual number of broods per pair or annual mean brood size in either species. Our study therefore does not suggest that breeding performance in Teal and Mallard is negatively affected by advancement of ice break-up at the population level. However, both species showed a within-season decline in brood size with increasing interval between ice break-up and hatching. Our study therefore highlights a disparity between individuals in their capacity to adjust to ice break-up date, late breeders having a lower breeding success than early breeders. We speculate that breeding success of both species may therefore decline should a consistent trend towards earlier springs occur.
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| 8. |
- Champagnon, Jocelyn, et al.
(författare)
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Assessing the genetic impact of massive restocking on wild mallard
- 2013
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Ingår i: Animal Conservation. - : Wiley: 12 months. - 1367-9430 .- 1469-1795. ; 16:3, s. 295-305
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Tidskriftsartikel (refereegranskat)abstract
- Captive-bred mallards Anas platyrhynchos have been released for hunting purposes at a very large scale in Europe since the mid-1970s. In spite of a potential genetic impact, the actual contribution of restocked mallards to the genome of the target population has received little attention. The genetic structure of modern wild mallards in the Camargue, Southern France, was assessed from two samples: one originating from shot birds in hunting bags and one from presumed wild ducks captured alive in a hunting-free reserve. Reference samples originated from five mallard farms, as well as from museum samples collected before the mid-1970s (i.e. before massive mallard releases started). Our results revealed that the genetic signature of wild wintering mallards has not changed significantly because museum and presumed wild samples from the Camargue hunting-free nature reserve were genetically similar, and clearly differentiated from the farm mallards. This suggests that mallard releases in the Camargue or elsewhere in France, although massive, have not actually translated into complete admixture of wild and captive genomes, most likely due to low survival of released birds once in the wild. Nevertheless, although genetic introgression of the wild population by captive-bred was contained, we found significant rates of hybridization between wild and captive-bred mallards in modern samples. This result suggests that long-term releases of captive-bred mallards, if carried on at such large scale, could compromise irreversibly the genetic structure and composition of European mallards. This work contributes to fill in the gap on the monitoring of the genetic consequences of large-scale game releases for exploitation.
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| 9. |
- Chauvet, Eric, et al.
(författare)
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Litter decomposition as an indicator of stream ecosystem functioning at local-to-continental scales : insights from the European RivFunction project
- 2016
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Ingår i: Large-scale ecology. - London : Academic Press. - 9780081009352 ; 55, s. 99-182
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Bokkapitel (refereegranskat)abstract
- RivFunction is a pan-European initiative that started in 2002 and was aimed at establishing a novel functional-based approach to assessing the ecological status of rivers. Litter decomposition was chosen as the focal process because it plays a central role in stream ecosystems and is easy to study in the field. Impacts of two stressors that occur across the continent, nutrient pollution and modified riparian vegetation, were examined at > 200 paired sites in nine European ecoregions. In response to the former, decomposition was dramatically slowed at both extremes of a 1000-fold nutrient gradient, indicating nutrient limitation in unpolluted sites, highly variable responses across Europe in moderately impacted streams, and inhibition via associated toxic and additional stressors in highly polluted streams. Riparian forest modification by clear cutting or replacement of natural vegetation by plantations (e.g. conifers, eucalyptus) or pasture produced similarly complex responses. Clear effects caused by specific riparian disturbances were observed in regionally focused studies, but general trends across different types of riparian modifications were not apparent, in part possibly because of important indirect effects. Complementary field and laboratory experiments were undertaken to tease apart the mechanistic drivers of the continental scale field bioassays by addressing the influence of litter, fungal and detritivore diversity. These revealed generally weak and context-dependent effects on decomposition, suggesting high levels of redundancy (and hence potential insurance mechanisms that can mitigate a degree of species loss) within the food web. Reduced species richness consistently increased decomposition variability, if not the absolute rate. Further field studies were aimed at identifying important sources of this variability (e.g. litter quality, temporal variability) to help constrain ranges of predicted decomposition rates in different field situations. Thus, although many details still need to be resolved, litter decomposition holds considerable potential in some circumstances to capture impairment of stream ecosystem functioning. For instance, species traits associated with the body size and metabolic capacity of the consumers were often the main driver at local scales, and these were often translated into important determinants of otherwise apparently contingent effects at larger scales. Key insights gained from conducting continental scale studies included resolving the apparent paradox of inconsistent relationships between nutrients and decomposition rates, as the full complex multidimensional picture emerged from the large-scale dataset, of which only seemingly contradictory fragments had been seen previously.
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| 10. |
- Dalby, Lars, et al.
(författare)
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The status of the Nordic populations of the Mallard (Anas platyrhynchos) in a changing world
- 2013
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Ingår i: Ornis Fennica. - : Finnish Omithological Soc. - 0030-5685. ; 90:1, s. 2-15
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Tidskriftsartikel (refereegranskat)abstract
- Dabbling ducks (Anas spp.) are importantmigratory quarry species, protected as a shared resource under international legislation. However, there is a lack of sufficient high-quality data on vital demographic rates and long-term trends in numbers to judge the conservation status of many duck populations at the flyway level. In response to reported declines in the North-West European flyway population of theMallard, we compiled available data on this species in the Nordic countries up to 2010. Generally, national breeding numbers showed increasing trends, wintering abundance showed variable trends, and productivitymeasures indicated stable or increasing trends.Major knowledge gaps were identified, namely the size of hunting bags, the influence of the released Mallards and the role of short-stopping in explaining changing patterns of wintering abundance across the North-West European flyway. Numerically the Nordic breeding population appears in “good condition”, and the wintering numbers have been either stable or increasing in the last two decades. The annual number of releases needs to be determined in order to judge the sustainability of the current levels of exploitation. Overall, none of the indicators showed alarming signs for the Mallard population in the Nordic countries when considered in isolation. However, the widespread decline in wintering numbers elsewhere across North-western Europe requires urgent pan-European action.
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