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Ülo Väli - One of the best experts on this subject based on the ideXlab platform.
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Movement patterns of an avian generalist predator indicate functional heterogeneity in agricultural landscape
Landscape Ecology, 2020Co-Authors: Ülo Väli, Gunnar Sein, Pawel Mirski, Urmas Abel, Grete Tõnisalu, Urmas SellisAbstract:Biodiversity is closely related to landscape heterogeneity, but both are difficult to evaluate directly. Apex predators, such as raptors, are potential surrogate indicators of diversity, but previous studies using a correlative approach have been heavily criticised. We evaluated whether space use by a generalist avian predator, the Lesser Spotted Eagle Clanga pomarina, is an effective indicator of functional landscape heterogeneity and evaluate mechanisms driving this relationship. We used GPS-tracking of Eagles over eight breeding seasons along with precise field mapping data for broad and detailed land-use types from Estonia, Eastern Europe. We analysed the effects of various landscape metrics and composition on movement patterns of Eagles. Activity centres of Eagles were associated with configurational heterogeneity, as evidenced by their foraging on the edges of small complex patches more often than expected at random. The Eagles also avoided roads (disturbance) and preferred forest edges (ecotones with abundant prey and perch sites). The importance of compositional heterogeneity was revealed by preferences for specific land-use types (e.g. spring-sown but not autumn-sown wheat); preferred crops changed over time. The model including only general land-use classes was outperformed by the model based on a detailed classification. Movement ecology provides an opportunity to biomonitor the heterogeneity of landscapes and adds a functional perspective to earlier raptor-biodiversity correlation studies. This suggests that in addition to GPS-tracking, large quantities of opportunistic observations by citizen scientists can be used to evaluate biodiversity across landscapes.
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Nest site selection and turnover patterns in support of conservation decisions: Case study of the Lesser Spotted Eagle in the core area of its global population
Forest Ecology and Management, 2019Co-Authors: Ugis Bergmanis, Ülo Väli, Katrīna Amerika, Rimgaudas TreinysAbstract:Abstract Forest-dwelling raptors nest in the same close, mature forest stands over many years. As mature stands are targets for timber harvesting, the conservation of nest sites should be integrated into commercial forestry practices. Ecological data supporting conservation decisions are essential for ensuring effective conservation, and minimising costs and conflicts among different stakeholders. Here, we analysed nest site selection and nest site turnover patterns in a typical mature-forest-dwelling raptor in the core area of its global population. Our aim was to provide a basis for nesting habitat conservation in the context of commercial forestry. The Lesser Spotted Eagle Clanga pomarina was found to prefer mature stands, located close to the forest’s edge, for nesting. Pine stands were largely avoided by nesting pairs, but the composition of other tree species was similar to stands located in surrounding forests. The Lesser Spotted Eagle occupied the nest for an average of three years, and the number of used nests within a territory increased progressively with the longevity of its occupation. Within a territory, the pair moved between alternate nests mostly up to 600 m. The results of this study suggest that long-term conservation approaches for mature-forest-dwelling raptors should use breeding territory, which contains several nest sites (or suitable stands) spaced at certain distances and covered by temporal buffer, as a target unit in conservation-supporting forestry practices.
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Genetic determination of migration strategies in large soaring birds: evidence from hybrid Eagles
Proceedings of the Royal Society B: Biological Sciences, 2018Co-Authors: Ülo Väli, Paweł Mirski, Mindaugas Dagys, Urmas Sellis, Grzegorz MaciorowskiAbstract:The relative contributions of genetic and social factors in shaping the living world are a crucial question in ecology. The annual migration of birds to their wintering grounds and back provides significant knowledge in this field of research. Migratory movements are predominantly genetically determined in passerine birds, while in large soaring birds, it is presumed that social (cultural) factors play the largest role. In this study, we show that genetic factors in soaring birds are more important than previously assumed. We used global positioning system (GPS)-telemetry to compare the autumn journeys and wintering ranges of two closely related large raptorial bird species, the greater Spotted Eagle Clanga clanga and the Lesser Spotted Eagle Clanga pomarina, and hybrids between them. The timing of migration in hybrids was similar to that of one parental species, but the wintering distributions and home range sizes were similar to those of the other. Tracking data were supported by habitat suitability modelling, based on GPS fixes and ring recoveries. These results suggest a strong genetic influence on migration strategy via a trait-dependent dominance effect, although we cannot rule out the contribution of social interactions.
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Timing of Breeding Events of the Lesser Spotted Eagle Clanga pomarina as Revealed by Remote Cameras and GPS-tracking
Ardea, 2018Co-Authors: Ülo VäliAbstract:Proper timing of events in the annual cycle is essential for successful breeding in birds, especially in long-distance migrants. In this study, the phenology of the main breeding phases, including arrival at and departure from the nesting site, is reported for a Lesser Spotted Eagle population. Most data were gathered by 12 to 22 trail cameras annually installed at Eagle nests. Additional information was obtained from two web cameras and up to nine GPS-tracked birds. Arrival and departure dates fluctuated between years, but no temporal trends were detected. There was no significant sex-dependent difference in mean arrival time; however, males departed significantly later than females and thus spent longer at the nesting site. Timing of egg-laying was determined solely by the arrival of the later partner. Breeding phenology of the Lesser Spotted Eagle is rather similar across its distribution range, although breeding tends to be earlier at the southern range limit.
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Nutritional Condition of Hybrid Nestlings Is Similar To That of Pure-Species Offspring of Spotted Eagles (Clanga clanga × C. pomarina)
Journal of Raptor Research, 2018Co-Authors: Grzegorz Maciorowski, Ülo Väli, Reuven Yosef, Piotr TryjanowskiAbstract:Hybridization, the interbreeding of different species, plays an important role in several evolutionary processes but can have detrimental effects on the species involved, including extinction. We documented increased levels of hybridization between two Clanga species (Lesser Spotted Eagle [Clanga pomarina] and Greater Spotted Eagle [C. clanga]), following a drastic change in the water regime of their habitats in the Biebrza River Valley, Poland. Due to broader combined food-niches of the parent species, we hypothesized that hybrid nestlings should have similar or better nutritional condition when compared to the nestlings of the pure-species pairs. Ptilochronology of the feathers of 119 nestlings (54 Lesser Spotted Eagle, 42 Greater Spotted Eagle, 23 hybrids), and a comparison of the growth and fault bars among the groups suggested a similarity in their nutritional status. However, the number of fault bars present underscored an existing problem in feeding conditions for both pure and hybrid species, which is probably an effect of environmental changes, particularly in the water regime, in the Biebrza River Valley. Our results suggest that hybrid nestlings are potentially available for recruitment into the breeding populations of the two sibling species and their hybrids, although their fertility has yet to be thoroughly investigated. The evolutionary consequences could be a coalescing of the species into one with more generalist environmental requirements that will allow better exploitation of the changing habitats.
Rimgaudas Treinys - One of the best experts on this subject based on the ideXlab platform.
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May sympatric Lesser Spotted Eagles and Black Storks compete for nesting sites in spatially varying environments
Baltic Forestry, 2019Co-Authors: Saulis Skuja, Gintautas Mozgeris, Rimgaudas TreinysAbstract:Sympatric species are likely to compete with one another unless there is a low degree of overlap in their resource use, in which case these species are able to coexist. Disclosing of biotic interactions between sympatric species is important from both theoretical and practical perspectives, especially when the species are of conservation concern. However, environmental heterogeneity may introduce variation in the intensity of biotic interactions due to differential a varying species responses to the environmental gradient. In this study, we analysed the overlap in nesting sites between the internationally protected, mature, forest-dwelling Lesser Spotted Eagle Clanga pomarina and the Black Stork Ciconia nigra. The importance of landscape heterogeneity for habitat segregation between these species was also assessed. The nesting sites of 123 pairs of Lesser Spotted Eagles and 78 pairs of Black Storks, located across different landscapes of the Central, Central-Eastern and Eastern Lithuanian ecoregions were described. A series of discriminant analyses were performed to explore the pattern of habitat differentiation between species nesting in the above-mentioned regions. The habitat differentiation was estimated by niche overlap values (range 0-1, with a value 0.6 suggested to be the threshold between coexistence and competition). Comparison of nesting sites of mature forest-dwellers resulted in the niche overlap values for Central, Central-Eastern and Eastern regions being 0.5, 0.63 and 0.55, respectively. These results indicated relatively high niche overdispersion between nesting sites occupied by Eagles and storks. Different variables and/or their combinations resulted in habitat differences in each ecoregion. Our data indicate that biotic interaction between species is mediated by environmental heterogeneity. Although our data tend to support the coexistence of the Black Stork and the Lesser Spotted Eagle, in certain regions these mature, forest-dwelling predators may use similar habitats and compete for prime sites under specific landscape structures. We, therefore, propose the necessity of the importance of a spatially-segregated estimation on biotic interactions when developing conservation programmes and allocating conservation actions within the target region.
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Nesting habitat overlap between the Common Buzzard Buteo buteo and the Lesser Spotted Eagle Clanga pomarina for conservation planning in Natura 2000 sites
Bird Study, 2019Co-Authors: Aušra Kamarauskaitė, Saulis Skuja, Rimgaudas TreinysAbstract:ABSTRACTCapsule: The nesting habitat of the Common Buzzard Buteo buteo and Lesser Spotted Eagle Clanga pomarina extensively overlap, indicating that they exploit similar resources.Aim: We aimed to ...
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Nesting habitat overlap between the Common Buzzard Buteo buteo and the Lesser Spotted Eagle Clanga pomarina for conservation planning in Natura 2000 sites
Bird Study, 2019Co-Authors: Aušra Kamarauskaitė, Saulis Skuja, Rimgaudas TreinysAbstract:ABSTRACTCapsule: The nesting habitat of the Common Buzzard Buteo buteo and Lesser Spotted Eagle Clanga pomarina extensively overlap, indicating that they exploit similar resources.Aim: We aimed to ...
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No adverse effects on Lesser Spotted Eagle breeding in an area of high White-tailed Eagle density
Journal of Ornithology, 2019Co-Authors: Deivis Dementavičius, Saulius Rumbutis, Daiva Vaitkuvienė, Mindaugas Dagys, Rimgaudas TreinysAbstract:In Gebieten mit hoher Seeadler-Dichte zu brüten, hat für Schreiadler keine Nachteile Schwächeren Greifvögeln entstehen oft tödliche oder fast-tödliche Nachteile, wenn sie sympatrisch mit deutlich stärkeren Greifvögeln brüten. Die Erholung der Seeadlerpopulationen ( Haliaeetus albicilla ) in letzter Zeit bedeutete eine Rückkehr des größten aller Greifvögel. In dieser Studie untersuchten wir, wie wichtig Habitatüberlappung und räumliche Verteilung für den Fortpflanzungserfolg des nur ein Drittel so großen Schreiadlers ( Clanga pomarina ) sind, der sympatrisch mit Seeadlern in Gebieten nahe der Ostsee brütet, in denen die Seeadlerdichte besonders hoch ist. Im Vergleich zu den Seeadlern gab es um die Brutplätze der Schreiadler herum weniger Gewässer, und sie nutzten landwirtschaftlich genutzte Flächen und Übergangshabitate häufiger als die Seeadler. Unabhängig von ihrem Abstand zu den Seeadlern benutzten die Schreiadler jedes Jahr genau die gleichen Brutplätze. Der Fortpflanzungserfolg der Schreiadler war unbeeinträchtigt von der Entfernung zum nächstgelegenen Seeadlerpaar und dessen Bruterfolg wie auch von der Anzahl von Seeadlerpaaren innerhalb eines Umkreises von 3 km. Unsere Ergebnisse legen nahe, dass der kleinere Schreiadler ohne feststellbaren Nachteil für seine Populationsdynamik mit großen Greifvögeln koexistieren kann. Mesopredators frequently suffer lethal and/or non-lethal negative effects when breeding in sympatry with more powerful apex predators. The recent recovery of the White-tailed Eagle Haliaeetus albicilla (WTE) population throughout its range indicates the return of the largest predator of the raptor communities there. In this study, we assess the importance of habitat overlap and spatial distribution to the reproduction of the Lesser Spotted Eagle Clanga pomarina (LSE), a species that breeds sympatrically in areas of high WTE density near the Baltic Sea, but is three times smaller than the latter. Fewer water bodies surround the nesting sites of the LSE, and it uses agricultural areas and transitional habitats more frequently than the WTE. The same breeding territories are faithfully occupied by the LSE annually, irrespective of the distance between these and those of the WTE. We found that the breeding success of the LSE was not affected by the proximity or breeding output of the nearest pair of WTEs, nor was this affected by the number of WTE pairs present within a 3-km radius of nests. Our data suggest that the smaller LSE coexists with an abundant top predator without any obvious adverse effects on its population dynamics.
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No adverse effects on Lesser Spotted Eagle breeding in an area of high White-tailed Eagle density
Journal of Ornithology, 2019Co-Authors: Deivis Dementavičius, Saulius Rumbutis, Daiva Vaitkuvienė, Mindaugas Dagys, Rimgaudas TreinysAbstract:Mesopredators frequently suffer lethal and/or non-lethal negative effects when breeding in sympatry with more powerful apex predators. The recent recovery of the White-tailed Eagle Haliaeetus albicilla (WTE) population throughout its range indicates the return of the largest predator of the raptor communities there. In this study, we assess the importance of habitat overlap and spatial distribution to the reproduction of the Lesser Spotted Eagle Clanga pomarina (LSE), a species that breeds sympatrically in areas of high WTE density near the Baltic Sea, but is three times smaller than the latter. Fewer water bodies surround the nesting sites of the LSE, and it uses agricultural areas and transitional habitats more frequently than the WTE. The same breeding territories are faithfully occupied by the LSE annually, irrespective of the distance between these and those of the WTE. We found that the breeding success of the LSE was not affected by the proximity or breeding output of the nearest pair of WTEs, nor was this affected by the number of WTE pairs present within a 3-km radius of nests. Our data suggest that the smaller LSE coexists with an abundant top predator without any obvious adverse effects on its population dynamics.
Miroslav Dravecký - One of the best experts on this subject based on the ideXlab platform.
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Abundance, distribution and trend of the Lesser Spotted Eagle (Aquila pomarina) breeding population in Slovakia
Slovak Raptor Journal, 2015Co-Authors: Miroslav Dravecký, Stefan Danko, Boris Maderic, Ján Topercer, Ján Kicko, Dušan Karaska, Zuzana Guziová, Karol ŠotnárAbstract:Several estimates of the Lesser Spotted Eagle breeding population in Slovakia were published in 1955-2002. In this study we estimate the breeding population of the Lesser Spotted Eagle by 1997 and 2014. By 1997, the estimated size of the breeding population was 762 pairs. In 2002 an estimate of the population size by 2000 was published at 800-900 pairs. By 2014 we estimate the breeding population of the Lesser Spotted Eagle in Slovakia at 600-800 pairs and the declining population trend in 2000-2013 at -23%. Our estimate is supported by the extrapolation from data obtained in 2011-2013 in eight selected Special Protection Areas (SPAs) within a framework of the project LIFE09 NAT/SK/000396 “Conservation of Aquila pomarina in Slovakia”. When analyzing abundance, density and trends in the species’ entire breeding range in Slovakia we first summarised the numbers of breeding pairs, their densities and trends within the selected SPAs and then explored the differences among them using ANOVA and cluster analysis. For the eight SPAs as a whole (n = 8) or partitioned by a grid of the Databank of Slovak Fauna (n = 119 squares) we calculated the interval estimates of the mean number of pairs (unweighted and weighted arithmetic means and medians). By summarising these estimates and extrapolating to the species’ entire breeding range in Slovakia (c. 28,935 km2) while increasing the sample size (n = 8, 9, 11 and 1 2 SPAs), the size estimates stabilise at a level of 670 (mean with 95%LCL = 507 and 95%UCL = 834) or 765 (median with 95%LCL = 393 and 95%UCL = 841) breeding pairs. The most reliable estimate of the breeding population of the Lesser Spotted Eagle in Slovakia by 2014 is a median of 765 pairs with a 95% confidence interval from 393 to 841 pairs and an interquartile range from 418 to 835 pairs. We estimate a 23% decrease in the breeding population during 2000-2013, i.e. a small decrease -1 (20-49%). Three methods of estimating were used: 1) comparing the numbers of pairs in the selected SPAs between 2000 and 2014 - indicates a decrease of -26%; 2) comparing the numbers of pairs from long-term monitoring in five areas (orographic units Vihorlatske vrchy Mts, Laborecka vrchovina Upland, Volovske vrchy Mts, Orava and Horne Ponitrie Regions) by the 1990s and 2014 - indicates a decrease of -20%; 3) comparing the numbers of pairs by 1997 in selected areas within the boundaries of the current SPAs with the number of pairs in the same SPAs by 2014 - indicates a decrease of -23%. In the eight selected SPAs the estimated decline was even more pronounced, reaching a median trend of -35% in the 95% confidence interval from -54% to +25%. The estimate by 1997 fits in with an increasing trend of published breeding population estimates in Slovakia during 1955-2002. The estimate by 2014 is lower than the estimate by 2000, and for the first time ever a declining trend is recorded. By 2014 the breeding grounds of the Lesser Spotted Eagle in Slovakia embrace an area of c. 28,935 km². Taking an estimate of 600-800 breeding pairs, the mean density varies between 2.1-2.8 pairs.100 km⁻².
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International Conference on the Conservation of the Lesser Spotted Eagle, Košická Belá, Slovakia, 2014
Slovak Raptor Journal, 2015Co-Authors: Zuzana Guziová, Miroslav DraveckýAbstract:Abstract The International Conference on the Conservation of the Lesser Spotted Eagle (Aquila pomarina) was held on September 25-27, 2014 in Lesanka Gesthouse at Košická Belá, Slovakia. It was organised by Raptor Protection of Slovakia (RPS) in cooperation with Východoslovenská energetika Holding a.s. The conference dealt with (i) delivering further inputs for updating the European Action Plan for the species, (ii) sharing information on biology and ecology of the species, and (iii) exchange of experience with best practice and innovative species conservation measures. A total of 59 participants from 1 4 countries attended the conference. The agenda included 17 presentations and 7 posters. Some of the contributions are published in Slovak Raptor Journal volume 9 (2015) as full papers, and a further 23 contributions are published as abstracts. The conference also included two field trips during which participants had the opportunity to observe the installation of console barriers on poles of 22 kV power lines, and typical habitats of the Lesser Spotted Eagle. The conference was organized within the framework of the project LIFE09NAT/SK/000396 Conservation of Aquila pomarina in Slovakia, implemented by Raptor Protection of Slovakia, Východoslovenská energetika Holding a.s., Stredoslovenská energetika, a.s. and Stredoslovenská energetika-Distribúcia, a.s. The project was cofinanced by EU-LIFE and the Ministry for Environment of the Slovak Republic.
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Abstracts of contributions presented at the International Conference on the Conservation of the Lesser Spotted Eagle, Slovakia, 2014
Slovak Raptor Journal, 2015Co-Authors: Miroslav Dravecký, Zuzana GuziováAbstract:Abstract The International Conference on the Conservation of the Lesser Spotted Eagle (Aquila pomarina) was held on September 25-27, 2014 in Lesanka Guesthouse at Košická Belá, Slovakia. The Conference was organized within the framework of the project LIFE09NAT/SK/000396 Conservation of Aquila pomarina in Slovakia, implemented by Raptor Protection of Slovakia, Východoslovenská energetika, a.s., Stredoslovenská energetika, a.s., and Stredoslovenská energetika - Distribúcia, a.s. This project was cofinanced by EU-LIFE and the Ministry for the Environment of the Slovak Republic. A total of 59 participants from 14 countries attended the conference. The conference agenda included 17 presentations and 7 posters. Some of the contributions are published in Slovak Raptor Journal volume 9 (2015) as full papers, and a further 23 contributions are published here as conference abstracts.
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Reproductive success, selected nest characteristics and the effectiveness of establishing protection zones of the Lesser Spotted Eagle (Aquila pomarina) population in Slovakia
Slovak Raptor Journal, 2015Co-Authors: Miroslav Dravecký, Stefan Danko, Boris Maderic, Ján Kicko, Dušan Karaska, Jozef Mihók, Zuzana GuziováAbstract:Abstract In 2011–201 4 monitoring of the Lesser Spotted Eagle (Aquila pomarina) breeding population was conducted in eight special protection areas in Slovakia. From a total of 272 successful breeding attempts by 1 49 breeding pairs during 4 breeding seasons 277 young birds were fledged. The average reproductive success ratio was thus 0.51 juv./pair present, 0.69 juv./breeding pair and 1 .37 juv./1 00 km2. In the surveyed period a total of 1 51 protection zones were established around the nests in 11 9 breeding territories, which provided protection for 1 7% of the breeding population of the Lesser Spotted Eagle in Slovakia. By testing the effectiveness of protection zones it was determined that in nests with an established protection zone the probability of successful raising of young is higher in comparison with nests without such a zone. The probability that breeding will be successful in the nests of breeding pairs without a protection zone was 48.1% (95% confidence intervals (CIs): 37.4–59.0%), and in nests with a protection zone 64.8% (95% CIs: 59.8–69.6%). Among the five most frequent nest tree species used by A. pomarina in Slovakia for breeding are Picea abies 61 × (28.4%), Pinus sylvestris 45× (20.9%), Quercus sp. 36× (1 6.7%), Fagus sylvatica 25× (11 .6%) and Abies alba 1 8× (8.4%). Among the rarer nest tree species used are Larix decidua 1 2× (5.6%) and Alnus glutinosa 3× (1 .4%), while a further 11 species of nest trees did not achieve even 1%. The highest number of nest trees (n = 21 5), i.e. 34 nests (1 5.8%), was found in the altitude range of 401–450 m a.s.l. and 29 nests (1 3.5%) at 351–400 m a.s.l. Other altitude zones were all below the 1 0% mark. A total of 54% of nests found (11 6 nests) are located in the altitude zone of 301–600 m a.s.l., and 71 nests (33%) in the zone 600–900 m a.s.l. The lowest situated nest was at an altitude of 1 50 m and the highest at 950 m; the average was 595.01 m a.s.l. The highest number of nests (n = 209) were located on trees in a range 1 5.1–20.0 m above the ground (n = 92, 44%), while the lowest nest found was at a height of 5 m and the highest at 30 m above the ground.
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Colour ringing programme of the Lesser Spotted Eagle (Aquila pomarina) population in Slovakia and its new results in the period 2009–2012
Slovak Raptor Journal, 2014Co-Authors: Miroslav Dravecký, Stefan Danko, Boris Maderic, Ján Kicko, Miloš Balla, Jozef Mihók, Ervín Hrtan, Tomáš Belka, Dušan KaraskaAbstract:Abstract In the years 2009-2012 a total of 316 individuals were marked in a colour ringing programme of the population ofA. pomarina in Slovakia. From this a total of 39 inds. were ringed with yellow readable plastic rings with a two-place alphanumeric code (all young in a nest) and 277 inds. (273 young and 4 adult inds.) with light-blue rings. For the entire period of the programme of marking the A. pomarina population in Slovakia in the years 2000-2012 a total of 952 inds. were ringed, 933 of which were young birds in nest and 19 adult individuals. In the period 2009-2012 48 records were obtained from observations of 35 individuals of different age categories (31 individuals from one to 11 years old, three of unknown age and one young individual about one month after fledging the nest). The age categories of immature individuals were determined, and six were found to be one-year-old individuals (12.5%) in the second calendar year of life after their first return from wintering grounds, six were two-year-old Eagles (12.5%) and five were three-year-old Eagles (10.4%) which spent breeding periods in Europe at a relatively small distance from their place of hatching. Adult individuals were found to be in their current breeding grounds at distances of 8-249 km from their hatching place. In the period 2000-2012 three individuals were recorded 3× and four individuals 2×. The results confirm breeding site fidelity in adults, but also the fidelity of immature individuals to their hatching place, and the return of one-year-old individuals from their wintering grounds to the vicinity of their hatching place immediately in the first year of life (that is, in the second calendar year).
Treinys Rimgaudas - One of the best experts on this subject based on the ideXlab platform.
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Relationship between the Productivity of the Lesser Spotted Eagle Aquila pomarina and Forest Characteristics at the Macrohabitat Level
2020Co-Authors: Treinys Rimgaudas, Mozgeris GintautasAbstract:Until now, forest characteristics of Lesser Spotted Eagle macrohabitat have received very little attention. Productivity relationships with macrohabitat forest characteristics are also undiscovered despite the fact that forests cover a considerable part of the Lesser Spotted Eagle macrohabitats. We investigated forest age and tree species composition in Lesser Spotted Eagle macrohabitats and their relationships with productivity of the species. The species at the macrohabitat level significantly avoided coniferous, pine and middle-aged forests and preferred deciduous, black alder and mature forests. We found no evidence that forest age and tree species composition in Lesser Spotted Eagle macrohabitats were related to the productivity of the species. We suggest that the population of the species can be adversely affected by unbalanced forestry not only at the nest-site, but also at the landscape levelVytauto Didžiojo universitetasŽemės ūkio akademij
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Comprehension of conservation costs in the context of wood economy: a case study on Lesser Spotted Eagle protection on special protection areas
2020Co-Authors: Mozgeris Gintautas, Treinys Rimgaudas, Činga GintautasAbstract:Modern forestry involves balancing multiple and often conflicting demands regarding the use and conservation of forest ecosystems. Protection of the Lesser Spotted Eagle (Aquila pomarina Brehm) and its nesting habitat in Natura 2000 sites is a good example of conservation solutions being directly connected to significant forest management restrictions. In Lithuania, the protection regime for the species in the Natura 2000 sites has been in place since 2004. However, neither the costs to the wood economy or the ecological benefits of the regime, or of alternative protection regimes, have been explored in detail. In this study, we aim to discuss a methodological framework to weigh up alternative regimes to protect the Lesser Spotted Eagle and its nesting habitat in the context of wood economy. We compared two approaches to protect the species and its habitat in three special protection areas (SPAs) designated for the Lesser Spotted Eagle. The current protection regime incorporates two types of measures: 1) for every estimated pair present in SPAs, two 3-5 ha mature forest stands are selected, along with protective zones 100 m wide around those stands. In the set-aside forest stands final felling is completely forbidden and other types of felling are restricted during the summer season. In the protective zones, all types of felling are restricted during the summer season, but permitted in other seasons; 2) For Lesser Spotted Eagle nests located outside the selected set-aside stands, final felling is restricted for a distance of 100 m around the nest throughout the year and other types of felling are also restricted during summer season. The Foundation for the Development of Nature Protection Projects has developed an alternative protection regime for this species in the SPAsGamtos tyrimų centro Ekologijos institutasVytauto Didžiojo universitetasŽemės ūkio akademij
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Coexistence of protected avian predators: does a recovering population of White-tailed Eagle threaten to exclude other avian predators?
2020Co-Authors: Treinys Rimgaudas, Mozgeris Gintautas, Skuja Saulis, Dementavičius Deivis, Rumbutis Saulius, Stončius DariusAbstract:The processes of competition and predation determine the degree to which species can coexist; the importance of competition in particular has been emphasized at high trophic levels. Competition exclusion will occur when habitat overlap between sympatric species is high. In this study, we investigated nesting habitat overlap between internationally protected diurnal tree-nesting avian predators of central Europe, namely, White-tailed Eagle (Haliaeetus albicilla), Lesser Spotted Eagle (Aquila pomarina), Black Stork (Ciconia nigra), and Osprey (Pandion haliaetus). We found significantly different nesting habitats among the study species and suggest that this could be a consequence of the resource-based segregation, but not a consequence of asymmetrical interspecific competition. The results also show that habitat of the recovering populations of White-tailed Eagle overlapped with the habitat used by the Lesser Spotted Eagle, Black Stork, and Osprey to varying extents with a niche overlap values being below the competition exclusion threshold. Nevertheless, we suggest that competition by White-tailed Eagle at a population level may limit Osprey, though not Lesser Spotted Eagle or Black StorkVytauto Didžiojo universitetasŽemės ūkio akademij
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May sympatric Lesser Spotted Eagles and black storks compete for nesting sites in spatially varying environments?
2020Co-Authors: Skuja Saulis, Mozgeris Gintautas, Treinys RimgaudasAbstract:Disclosing of biotic interactions between sympatric species is important from both theoretical and practical perspectives, especially when the species are of conservation concern. In ecologically similar species, environmental heterogeneity may change the intensity of their competitive interactions due to varying species responses along the environmental gradients. In this study, we analysed the overlap in nesting sites between the internationally protected, mature forest-dwelling Lesser Spotted Eagle Clanga pomarina and the Black Stork Ciconia nigra. The importance of landscape heterogeneity for habitat segregation between these species was also assessed. The nesting sites of 123 pairs of Lesser Spotted Eagles and 78 pairs of Black Storks, located across different landscapes of the Central, Central-Eastern and Eastern Lithuanian ecoregions were described. A series of discriminant analyses were performed to explore regional patterns of habitat differentiation between the species. Habitat differentiation between the species was estimated by niche overlap values (range 0-1, with a value 0.6 suggested to he the threshold between coexistence and competition), which were 0.5, 0.63 and 0.55 for the Central, Central-Eastern and Eastern ecoregions, respectively Different habitat factors and/or their combinations explained the habitat differentiation between the species in each ecoregion. Although our data shows the coexistence of the Lesser Spotted Eagle and the Black Stork, in certain regions these mature forest-dwelling predators may use too similar habitats and compete for prime sites under specific landscape structures and short supply of suitable patches. Therefore, we propose the necessity of the importance of a regional estimation on biotic interactions when developing conservation programmes and allocating conservation actions within the target regionGamtos tyrimų centrasVilniaus universitetasVytauto Didžiojo universiteta
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Past and present nest-site requirements of the Lesser Spotted Eagle (Aquila pomarina C.L.Brehm) and their possible conflicts with timber harvesting
2019Co-Authors: Treinys Rimgaudas, Mozgeris GintautasAbstract:Recently, the growing demand for raw timber has resulted in the intensification of forest use in the Baltic countries. The aim of this study was to examine whether the increased timber harvesting during the last decade has influenced the requirements of the Lesser Spotted Eagle (Aquila pomarina C.L.Brehm) for their nest-sites. In 2004, 7% of checked Lesser Spotted Eagle territories were disturbed by forestry operations. The general tendency was that the characteristics of stands used for nesting differed from the average forest stand characteristics in the landscape less than a decade ago. Eagles were found to nest on 19 different forest types, while previously just 13 of such forest types had been recorded. Less productive forests (2nd site class) and normally irrigated stands were not avoided nowadays. The average age of nest stands decreased by 16 years. Though oak remained one of the most preferred nest-trees (20% of all cases), spruce became the most common one (48%). This leads to the assumption, that the Eagles are less selective nowadays than in the past. The increased timber harvesting during the last decade might explain why Eagles switched to nest in stands, more similar to the surrounding forest landscape than in the past, and why some nest-site preferences remained and others disappeared. It is likely that during the next 30 years forest operations will be one of the most important factors, having an effect on the Lesser Spotted Eagle population in LithuaniaVytauto Didžiojo universitetasŽemės ūkio akademij
Niclas Backström - One of the best experts on this subject based on the ideXlab platform.
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Sex- and species-biased gene flow in a Spotted Eagle hybrid zone.
BMC Evolutionary Biology, 2011Co-Authors: Niclas Backström, Ülo VäliAbstract:Background Recent theoretical and empirical work points toward a significant role for sex-chromosome linked genes in the evolution of traits that induce reproductive isolation and for traits that evolve under influence of sexual selection. Empirical studies including recently diverged (Pleistocene), short-lived avian species pairs with short generation times have found that introgression occurs on the autosomes but not on the Z-chromosome. Here we study genetic differentiation and gene flow in the long-lived greater Spotted Eagle (Aquila clanga) and Lesser Spotted Eagle (A. pomarina), two species with comparatively long generation times.
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Sex− and species−biased gene flow in a Spotted Eagle hybrid zone
BMC Evolutionary Biology, 2011Co-Authors: Niclas Backström, Ülo VäliAbstract:Background Recent theoretical and empirical work points toward a significant role for sex-chromosome linked genes in the evolution of traits that induce reproductive isolation and for traits that evolve under influence of sexual selection. Empirical studies including recently diverged (Pleistocene), short-lived avian species pairs with short generation times have found that introgression occurs on the autosomes but not on the Z-chromosome. Here we study genetic differentiation and gene flow in the long-lived greater Spotted Eagle ( Aquila clanga ) and Lesser Spotted Eagle ( A. pomarina ), two species with comparatively long generation times. Results Our data suggest that there is a directional bias in migration rates between hybridizing Spotted Eagles in eastern Europe. We find that a model including post divergence gene flow fits our data best for both autosomal and Z-chromosome linked loci but, for the Z-chromosome, the rate is reduced in the direction from A. pomarina to A. clanga . Conclusions The fact that some introgression still occurs on the Z-chromosome between these species suggests that the differentiation process is in a more premature phase in our study system than in previously studied avian species pairs and that could be explained by a shorter divergence time and/or a longer average generation time in the Spotted Eagles. The results are in agreement with field observations and provide further insight into the role of sex-linked loci for the build-up of barriers to gene flow among diverging populations and species.