| 1. |
- Sokolik, Adrian S., et al.
(författare)
-
Mercury concentrations in sediment and fish from Nanay River, Peru – a small-scale gold mining area.
- 2006
-
Ingår i: Abstracts of Eighth International Conference on Mercury as a Global Pollutant. - 1932078657 ; , s. 574-
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Nanay River in the peruvian Amazonian rain forest supports 300 000 inhabitants in the city of Iquitos and surrounding villages with drinking water and fish for consumption. The river has been polluted with mercury, due to the use of the amalgamation method for gold extraction. This has resulted in that local people have got increased levels of mercury, up to 45 mg mercury per litre of blood. The aim of this study was to evaluate the concentrations of mercury in sediment and fish in the Nanay River, Peru, and to study eventual relation between fish mercury concentrations and mercury concentrations in sediment and water parameters such as dissolved organic matter, pH, dissolved oxygen and turbidity. In October 2005, eleven sample points for river water and sediment were established, from the gold mining activities close to Pucaurco westwards (18M 0605010, UTM 9579526) to Pampa Chica eastwards, drinking water source for Iquitos, (18M 0691053, UTM 9585255) in the region Loreto in Peru. Water temperature, conductivity,total dissolved ions, turbidity, dissolved oxygen and pH was measured in the field. Five species of predatory fishes were collected within the study area, where Pintuyacu Riverjoins Nanay River. The samples are currently subject to analyses in Sweden and results will be obtained during the spring. Based on the results, information will be sent to the Regional Government in the region of Loreto about the current state and recommended actions to prevent further contamination.
|
|
| 2. |
- Carpio, A. J., et al.
(författare)
-
Angling as a source of non-native freshwater fish : a European review
- 2019
-
Ingår i: Biological Invasions. - : Springer Science and Business Media LLC. - 1387-3547 .- 1573-1464. ; 21:11, s. 3233-3248
-
Tidskriftsartikel (refereegranskat)abstract
- In a context of the growing concern about the impact of biological invasions, our objective is to review the role of those non-native species that have primarily been introduced for angling purposes in at least one European country. We are particularly interested in: (1) the relative role of sport fish species in the context of non-native species introductions; (2) assessing the relative importance of different fish taxa; (3) identifying similarity patterns in the composition of the angling fish species introduced throughout the continent, and (4) assessing the underlying factors that drive their diversity in Europe. According to our results, 23.6% of the freshwater fish introduced into Europe during the last century were released primarily for angling purposes. The species composition differed among countries, with a higher diversity of introduced angling species in larger countries and in those with a greater GDP per capita, along with a lower latitude. This review stresses that angling was a significant pathway for the introduction of invasive fish species into Europe in the last century. Furthermore, some of the introduced angling species had severe environmental impacts on many European regions. However, introductions of non-native angling species are still occurring. Therefore, existing EU regulations need better enforcement as well as to increase public awareness regarding invasive fish. This will help to preserve biodiversity and improve the sustainability of current angling schemes in increasingly managed European freshwater ecosystems. However, non-native fish could make angling sustainable, although not for biodiversity generally.
|
|
| 3. |
- Carpio, Antonio J., et al.
(författare)
-
Effects of wild boar predation on nests of wading birds in various Swedish habitats
- 2016
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 62:4, s. 423-430
-
Tidskriftsartikel (refereegranskat)abstract
- The wild boar has, over the past few decades, undergone an expansion in Europe, which may have negatively affected ground-nesting bird populations and particularly those of wading birds. The aim of this study was to evaluate predation on waders’ nests by wild boar in Sweden, where this species has been increasing since its reintroduction. This was done by placing artificial nests in seven different study areas. A comparison was then made of predation rates of the nests placed on control plots (areas in which no wild boar were present but other predators were) and plots containing different abundances of wild boar. Contrary to our expectations, the proportion of nests predated was significantly lower in those areas in which wild boar were present, with a predation rate of 54 %, whereas the predation rate was 87.5 % in the others. The wild boar was identified as the second most important nest predator in the plots in which it was present, accounting for 18 % of the predated nests. The main predator on both types of plots was the red fox, which was responsible for 28 and 38.5 % of the predated nests on plots with/without wild boar, respectively. Interestingly, predation by badgers occurred principally in areas in which the wild boar was absent (34.5 % of the predated nests), whereas only one nest was predated by this predator in areas containing wild boar. It is not, however, possible to state whether predation by badgers was lower because of the presence of wild boar or whether this was owing to the fact that badgers do not select those particular patches because of habitat features.
|
|
| 4. |
- Carpio, Antonio J., et al.
(författare)
-
Hunting as a source of alien species : a European review
- 2017
-
Ingår i: Biological Invasions. - : Springer Science and Business Media LLC. - 1387-3547 .- 1573-1464. ; 19:4, s. 1197-1211
-
Tidskriftsartikel (refereegranskat)abstract
- Hunting activities are responsible for the translocation and restocking of millions of animals throughout Europe, including the introduction of alien species. In a context of the growing use of game translocations and of increasing concern about the impact of biological invasions, our goal is to review the role of alien species introduced primarily for hunting purposes on the European scale. In particular, we explore: (1) the relative importance of game species in the context of alien species introductions; (2) the temporal evolution of the number of species introduced for hunting purposes; (3) the contribution of different taxa; (4) the pattern of introduced game species composition across countries (in terms of similarity), and (5) the underlying human demographic factors driving the diversity of introduced game species per country. According to our results, 24.3% of the mammals and 30.2% of the birds introduced into Europe during the last century were released primarily for hunting purposes, in total, 93 species (63 birds and 36 mammals), the most important taxa being Artiodactyls, Anseriformes and Galliformes. The species composition differed among countries, with a higher diversity of introduced game species in larger countries and in those with a higher human population density and proportion of hunters. This review stresses that hunting was a significant pathway for the introduction of invasive species into Europe in the last century. Since some of the game species introduced have had severe environmental impacts on many European regions, and introductions of non-native game species are still occurring, it is essential to improve regulations and increase public awareness regarding invasive game animals. This will help to preserve biodiversity and improve the sustainability of current hunting schemes in increasingly managed European ecosystems.
|
|
| 5. |
- Carpio, Antonio J., et al.
(författare)
-
Wild boar effects on fungal abundance and guilds from sporocarp sampling in a boreal forest ecosystem
- 2022
-
Ingår i: Animals. - : MDPI. - 2076-2615. ; 12:19
-
Tidskriftsartikel (refereegranskat)abstract
- Native wild boar (Sus scrofa) populations are expanding across Europe. This is cause for concern in some areas where overabundant populations impact natural ecosystems and adjacent agronomic systems. To better manage the potential for impacts, managers require more information about how the species may affect other organisms. For example, information regarding the effect of wild boar on soil fungi for management application is lacking. Soil fungi play a fundamental role in ecosystems, driving essential ecological functions; acting as mycorrhizal symbionts, sustaining plant nutrition and providing defense; as saprotrophs, regulating the organic matter decomposition; or as plant pathogens, regulating plant fitness and survival. During autumn (Sep–Nov) 2018, we investigated the effects of wild boar (presence/absence and rooting intensity) on the abundance (number of individuals) of fungal sporocarps and their functional guilds (symbiotic, saprotrophic and pathogenic). We selected eleven forested sites (400–500 × 150–200 m) in central Sweden; six with and five without the presence of wild boar. Within each forest, we selected one transect (200 m long), and five plots (2 × 2 m each) for sites without wild boar, and ten plots for sites with boars (five within and five outside wild boar disturbances), to determine the relationship between the intensity of rooting and the abundance of sporocarps for three fungal guilds. We found that the presence of wild boar and rooting intensity were associated with the abundance of sporocarps. Interestingly, this relationship varied depending on the fungal guild analyzed, where wild boar rooting had a positive correlation with saprophytic sporocarps and a negative correlation with symbiotic sporocarps. Pathogenic fungi, in turn, were more abundant in undisturbed plots (no rooting) but located in areas with the presence of wild boar. Our results indicate that wild boar activities can potentially regulate the abundance of fungal sporocarps, with different impacts on fungal guilds. Therefore, wild boar can affect many essential ecosystem functions driven by soil fungi in boreal forests, such as positive effects on energy rotation and in creating mineral availability to plants, which could lead to increased diversity of plants in boreal forests.
|
|
| 6. |
- Cichon, M, et al.
(författare)
-
Mass-dependent mass loss in breeding birds : getting the null hypothesis right
- 1999
-
Ingår i: Oikos. - : JSTOR. - 0030-1299 .- 1600-0706. ; 87:1, s. 191-194
-
Tidskriftsartikel (refereegranskat)abstract
- An assumption central to many tests of statistical association between two variables is the null expectation of zero association. Here, we draw attention to the fact that in many published tests of mass-dependent mass loss in breeding birds, this assumption has been violated. We show that a correct null hypothesis can be derived by using resampling methods, and analyse three data sets (two previously published) from passerine birds to illustrate the approach. Our results show, that under a correct null hypothesis, the biological interpretation of the previously published results is reversed-initially heavy birds do actually lose less mass (relative to their weight) than the initially light birds.
|
|
| 7. |
- Djerdali, Sofia, et al.
(författare)
-
Food supply and external cues limit the clutch size and hatchability in the White Stork Ciconia ciconia
- 2008
-
Ingår i: Acta Ornithologica. - 0001-6454 .- 1734-8471. ; 43:2, s. 145-150
-
Tidskriftsartikel (refereegranskat)abstract
- Clutch size is an important life history trait and factors such as nest predation and food availability can both be of crucial importance for its variation in nature. The aim of the present study was to evaluate the effects of extra food on clutch size, laying date and hatching success in the White stork Ciconia ciconia. Three different colonies of White stork were studied over a three-year period where there was difference in both food availability and precipitation. This study demonstrated that an extra food supply during the pre-laying period had a positive effect on clutch size - nests with extra food had a larger clutch size. There was also an advance in laying date and a higher hatching success in nests with access to extra food. In addition to food supply, clutch size was independently affected by rainfall, which suggests that parents additionally also were sensitive to other external cues than to the extra food. Furthermore, this study also suggests that an extra food during the incubation period could probably help the parents to solve the conflict between incubation behaviour and minimizing the time off the nest, i.e. increasing nest attentiveness in nests with extra food.
|
|
| 8. |
- Guerrero-Casado, José, et al.
(författare)
-
Assessment of the suitability of latrine counts as an indirect method by which to estimate the abundance of European rabbit populations at high and low abundance
- 2020
-
Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 66:1
-
Tidskriftsartikel (refereegranskat)abstract
- Monitoring European rabbit (Oryctolagus cuniculus) populations using suitable methods is crucial, especially in those areas in which endangered predators remain and rabbits occur at low densities. We first counted the number of rabbits, the number of scattered pellets, and the number of latrines counted within 16 plots established in areas of low rabbit density, showing that the number of rabbits counted inside the plots was more closely correlated with the number of pellets counted than with the number of latrines. In addition, no latrines were found in 8 plots. In 53 walking transects, the number of pellets m−2 and the number of latrines km−1 had a positive relationship, but no significant correlation was obtained between the two methods when only the transects with a low rabbit abundance were selected. These results suggest that although counting latrines can be useful to compare areas with different abundances, it may underestimate rabbit abundance at low abundances where counting scattered pellets is, therefore, the most accurate alternative. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
|
|
| 9. |
|
|
| 10. |
- Hillström, Lars
(författare)
-
Estimation of state and identification of complex modulus based on measurements om a bar traversed by waves
- 2001
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Estimation of state and identification of complex modulus based on measurements on non-uniform rods and beams have been studied theoretically and experimentally. Two principal cases were studied. In the first case, the material properties are fully known and the state at a section is to be estimated. In the second case, the complex modulus is to be identified (and optionally the state is to be estimated). Nothing needs to be known about supports, structures and loads outside the rod and beam segments under consideration. In particular, analytical expressions of the standard deviation of the non-parametric complex modulus were derived for a uniform rod.Experimental tests were performed with rods of polymethyl methacrylate (PMMA) and polypropylene (PP) and with beams of aluminium, PMMA and PP. Both parametric and non-parametric complex moduli were determined in the frequency domain. For a uniform rod, parametric complex moduli were determined also in the time domain.It was found that the identification of the non-parametric complex modulus and the estimation of state may be inaccurate at certain discrete frequencies. It was shown how such inaccuracies can be avoided in the frequency range of interest by use of more than the minimum number of measurement sections and a non-uniform distribution of them. If a parametric complex modulus is used, the results should be compared with those for a non-parametric modulus. The parametric complex moduli determined in the time domain deviated more than expected from the complex moduli determined in the frequency domain. The reasons for these deviations are not fully understood.
|
|
