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BackgroundPopulations living in fragmented habitats may suffer from loss of genetic variation and reduced between-patch dispersal, which are processes that can result in genetic differentiation. This occurs frequently in species with reduced mobility, whereas genetic differentiation is less common among mobile species such as migratory birds. The high dispersal capacity in the latter species usually allows for gene flow even in fragmented landscapes. However, strongly philopatric behaviour can reinforce relative isolation and the degree of genetic differentiation. The Southern Dunlin (Calidris alpina schinzii) is a philopatric, long-distance migratory shorebird and shows reduced dispersal between isolated breeding patches. The endangered population of the Southern Dunlin breeding at the Baltic Sea has suffered from habitat deterioration and fragmentation of coastal meadows. We sampled DNA across the entire population and used 12 polymorphic microsatellite loci to examine whether the environmental changes have resulted in genetic structuring and loss of variation.ResultsWe found a pattern of isolation-by-distance across the whole Baltic population and genetic differentiation between local populations, even within the southern Baltic. Observed heterozygosity was lower than expected throughout the range and internal relatedness values were positive indicating inbreeding.ConclusionsOur results provide long-term, empirical evidence for the theoretically expected links between habitat fragmentation, population subdivision, and gene flow. They also demonstrate a rare case of genetic differentiation between populations of a long-distance migratory species. The Baltic Southern Dunlin differs from many related shorebird species that show near panmixia, reflecting its philopatric life history and the reduced connectivity of its breeding patches. The results have important implications as they suggest that reduced connectivity of breeding habitats can threaten even long-distance migrants if they show strong philopatry during breeding. The Baltic Southern Dunlin warrants urgent conservation efforts that increase functional connectivity and gene flow between breeding areas.

Aim Abundances of animals vary according to species-specific habitat selection, but habitats are undergoing rapid change in response to anthropogenic alterations of land use and climate. The long-term decline of snowfall is one of the most dramatic abiotic changes in boreal regions, with potential to alter species communities and shape future ecosystems. However, the effects of snow cover on habitat-specific abundances remain unclear for many taxa. Here we explore whether long-term declines in snow cover affect the abundances of overwintering birds. Taxon Fifty bird species. Location Finland, Northern Europe. Methods We used generalized linear mixed models to analyse citizen-led monitoring data from 196 transects over a 32-year period to assess whether abundances of birds have changed in built-up areas, farmlands and forests, and whether these covary with warming temperatures and decreasing snow. We then explored if changes in abundance can be explained by body mass, migration strategy or feeding guilds of the species. Results Over the study period, the abundance of overwintering birds increased. This increase was most pronounced in farmlands (69.6%), where abundances were positively associated with decreasing snow depth. On the other hand, while abundances in built-up habitats (19.5%) decreased over the study period, they increased in periods of high snow depths. Finally, we found that the short-distance migration strategy explains changes in bird abundances with snow. In farmlands, ground feeding birds and heavier birds also show a positive trends in abundance with decreasing snow depths. Main conclusions Local snow conditions are driving habitat selection of birds in the winter; birds in farmlands were most responsive to a decrease in snow depth. Changing snow depths can affect bird movements across habitats in the winter, but also influence migratory patterns and range shifts of species.

Ederfuglen er i alvorlig tilbagegang i Østersøen og Nordsøen, kønsbalancen er skæv med et stort overtal af hanner, og derfor er en international forvaltningsplan er under udarbejdelse i regi af Vandfugleaftalen (AEWA). Bæredygtig forvaltning kræver opdateret viden om bestandens trækforhold og dødelighed, og den bedste kilde til denne viden er ringmærkning. Denne rapport giver et overblik over det omfattende materiale om ringmærkede og genmeldte ederfugle i Østersø/Nordsøområdet, i alt næsten 18.000 genmeldinger af mere end 125.000 ringmærkede fugle siden 1970. Detaljerede statistiske analyser af dette materiale vil kunne give vigtig ny viden om hvor ynglefugle fra forskellige områder tilbringer vinteren, og om dødeligheden hos begge køn og alle aldersklasser.

1. An automatic bird sound recognition system is a useful tool for collecting data of different bird species for ecological analysis. Together with autonomous recording units (ARUs), such a system provides a possibility to collect bird observations on a scale that no human observer could ever match. During the last decades, progress has been made in the field of automatic bird sound recognition, but recognizing bird species from untargeted soundscape recordings remains a challenge. 2. In this article, we demonstrate the workflow for building a global identification model and adjusting it to perform well on the data of autonomous recorders from a specific region. We show how data augmentation and a combination of global and local data can be used to train a convolutional neural network to classify vocalizations of 101 bird species. We construct a model and train it with a global data set to obtain a base model. The base model is then fine-tuned with local data from Southern Finland in order to adapt it to the sound environment of a specific location and tested with two data sets: one originating from the same Southern Finnish region and another originating from a different region in German Alps. 3. Our results suggest that fine-tuning with local data significantly improves the network performance. Classification accuracy was improved for test recordings from the same area as the local training data (Southern Finland) but not for recordings from a different region (German Alps). Data augmentation enables training with a limited number of training data and even with few local data samples significant improvement over the base model can be achieved. Our model outperforms the current state-of-the-art tool for automatic bird sound classification. An automatic bird sound recognition system is a useful tool for collecting data of different bird species for ecological analysis. Together with autonomous recording units (ARUs), such a system provides a possibility to collect bird observations on a scale that no human observer could ever match. During the last decades, progress has been made in the field of automatic bird sound recognition, but recognizing bird species from untargeted soundscape recordings remains a challenge. In this article, we demonstrate the workflow for building a global identification model and adjusting it to perform well on the data of autonomous recorders from a specific region. We show how data augmentation and a combination of global and local data can be used to train a convolutional neural network to classify vocalizations of 101 bird species. We construct a model and train it with a global data set to obtain a base model. The base model is then fine-tuned with local data from Southern Finland in order to adapt it to the sound environment of a specific location and tested with two data sets: one originating from the same Southern Finnish region and another originating from a different region in German Alps. Our results suggest that fine-tuning with local data significantly improves the network performance. Classification accuracy was improved for test recordings from the same area as the local training data (Southern Finland) but not for recordings from a different region (German Alps). Data augmentation enables training with a limited number of training data and even with few local data samples significant improvement over the base model can be achieved. Our model outperforms the current state-of-the-art tool for automatic bird sound classification. Using local data to adjust the recognition model for the target domain leads to improvement over general non-tailored solutions. The process introduced in this article can be applied to build a fine-tuned bird sound classification model for a specific environment.

Differing environmental conditions can have profound effects on many behaviours in animals, especially where species have large geographic ranges. Seasonal changes or progression through life history stages impose differential constraints, leading to changes in behaviours. Furthermore, species which show flexibility in behaviours, may have a higher capacity to adapt to anthropogenic-induced changes to their environment. The red-throated diver (RTD) is an aquatic bird, that is able to forage in both freshwater and marine environments, though little else is known about its behaviours and its capacity to adapt to different environmental conditions. Here, we use time-depth recorders and saltwater immersion loggers to examine the foraging behaviour of RTDs from three regions across northwest Europe. We found that in the breeding season, birds from two regions (Iceland and Scotland) foraged in the marine environment, while birds from Finland, foraged predominantly in freshwater. Most of the differences in diving characteristics were at least partly explained by differences in foraging habitat. Additionally, while time spent foraging did not change through the breeding season, dives generally became more pelagic and less benthic over the season, suggesting RTDs either switched prey or followed vertical prey movements, rather than increasing foraging effort. There was a preference for foraging in daylight over crepuscular hours, with a stronger effect at two of the three sites. Overall, we provide the first investigation of RTD foraging and diving behaviour from multiple geographic regions and demonstrate variation in foraging strategies in this generalist aquatic predator, most likely due to differences in their local environment.

© 2020, Marine Ornithology. All rights reserved. Recently, Red-throated Loons Gavia stellata (RTL) have been the subject of increased interest due to their negative interactions with shipping, offshore wind farms, and other marine industry activities. This has driven a desire to quantify the behaviour and ecology of this understudied species, particularly during the non-breeding season. To achieve this, Time Depth Recorder (TDR) and Global Location Sensor (GLS) tags were deployed on individuals from several European locations. Due to an incidental mortality, one set of tags was retrieved early. The single set of tags recorded activity from June to August 2018. The TDR collected records for 14 d, providing the first ever biologging data on RTL foraging in Europe. The bird was tagged 90 km from the coast; therefore, it only used freshwater lakes and was never recorded entering saltwater. The individual mostly undertook shallow dives, with maximum and mean depths of 20 m and 5.4 m, respectively. Foraging constituted 22.9% of total activity during the sampling period. The RTL had diel foraging patterns, with dives being shallower and more frequent at times of “twilight” compared to “daylight.” These results provide novel information on an RTL’s diurnal patterns of water depth usage and foraging effort during the summer, demonstrating the potential of data loggers to provide key insights into the foraging ecology of this species.

Climate change is driving species to shift their distributions toward high altitudes and latitudes, while habitat loss and fragmentation may hamper species ability to follow their climatic envelope. These two drivers of change may act in synergy, with particularly disastrous impacts on biodiversity. Protected areas, PAs, may thus represent crucial buffers against the compounded effects of climate change and habitat loss. However, large-scale studies assessing the performance of PAs as such buffers remain scarce and are largely based on species occurrence data. Conversely, abundance data have proven to be more reliable for addressing changes in wildlife populations under climate change. We evaluated changes in bird abundance from the 1970s-80s to the 2000s inside and outside PAs at the trailing range edge of 30 northern bird species and at the leading range edge of 70 southern species. Abundances of retracting northern species were higher and declined less inside PAs at their trailing range edge. The positive effect of PAs on bird abundances was particularly marked in northern species that rely strongly on PAs, that is, their density distribution is largely confined within PAs. These species were nearly absent outside PAs in the 2000s. The abundances of southern species were in general lower inside PAs and increased less from the 70s-80s to 2000s. Nonetheless, species with high reliance on PAs had much higher abundances inside than outside PAs in the 2000s. These results show that PAs are essential in mitigating the retraction of northern species, but also facilitate northward expansions of southern species highly reliant on PAs. Our study provides empirical evidence documenting the role of PAs in facilitating species to adjust to rapidly changing climatic conditions, thereby contributing to the mitigation of impending biodiversity loss. PAs may thus allow time for initiating wider conservation programs on currently unprotected land.

Climate change has ubiquitous impacts on ecosystems and threatens biodiversity globally. One of the most recognized impacts are redistributions of species, a process which can be hindered by habitat degradation. Protected areas (PAs) have been shown to be beneficial for preserving and reallocating species occurrences under climate change. Yet, studies investigating effects of PA networks on species' range shifts under climate change remain scarce. In theory, a well-connected network of PAs should promote population persistence under climate change and habitat degradation. To study this, we evaluated the effects of PA coverage on avian communities in Finland between two study periods of 1980-1999 and 2000-2015. Climate-driven community impacts were investigated by using community temperature index (CTI). We used linear models to study the association of PA coverage and the CTI changes in southern, central and northern Finland. In northern and central Finland, higher PA coverage was associated with lower changes in CTI and 45% PA coverage in northern and 13% in central Finland corresponded with complete mitigation of CTI increase. These results indicate that higher PA coverage strongly increases community resilience to warming climate. However a similar association between PA coverage and changes in CTI was not apparent in southern Finland. The PA coverage in southern Finland was much lower than in the two other sections and thus, may be too sparse to favour community resilience against climate change. The results provide empirical evidence for the international need to rapidly expand PA networks and halt biodiversity loss.

Human actions have led to loss and degradation of wetlands, impairing their suitability as habitat especially for waterbirds. Such negative effects may be mitigated through habitat management. To date scientific evidence regarding the impacts of these actions remains scarce. We studied guild specific abundances of breeding and staging birds in response to habitat management on 15 Finnish wetlands. In this study management actions comprised several means of vegetation removal to thwart overgrowth. Management cost efficiency was assessed by examining the association between site-specific costs and bird abundances. Several bird guilds exhibited positive connections with both habitat management as well as with invested funds. Most importantly, however, red-listed species and species with special conservation concern as outlined by the EU showed positive correlations with management actions, underlining the conservation value of wetland management. The results suggest that grazing was especially efficient in restoring overgrown wetlands. As a whole this study makes it clear that wetland habitat management constitutes a feasible conservation tool. The marked association between invested funds and bird abundance may prove to be a valuable tool for decision makers when balancing costs and impact of conservation measures against one another.

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Climate change may affect bird populations both directly by changing the weather conditions, and indirectly through changes in the food chain. While both theoretical and empirical studies have shown climate change having drastic impacts on polar areas, its consequences on Arctic bird species are still poorly known. Here we investigated how weather and changes in predator–prey interactions affected the annual growth rates of sub-Arctic birds by monitoring the breeding numbers of three duck and seven wader species in the alpine tundra of Finnish Lapland during 2005–2015 (except for 2006). We hypothesized that growth rates of waterbirds would be positively associated with warm and dry weather due to improved reproductive success. Furthermore, we tested the hypothesis that waterbirds have a higher reproductive success during the cyclic rodent peaks, when predators mainly prey on rodents, than during the decline and low phases of the cycle, when predation pressure towards waterbirds increases. Results showed that population growth rates of breeding ducks were negatively associated with the sum of rainfall in the previous year. In waders, growth rates were positively associated with the phase of the rodent cycle in the same year. Our results emphasize the importance of monitoring Arctic bird populations on their breeding areas to explore what the consequences of climate change might be for breeding waterbirds by linking the effects of both weather and rodent abundance. peerReviewed

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Human induced climate change will affect global biodiversity considerably. One of the most studied consequences is climate driven redistributions of species. Simultaneously, increasing land development resulting in habitat loss will add difficulties for species to adapt and redistribute under changing climate. Failing to move or adapt, species face a risk of extinction. The high latitude and high altitude species are facing increased risk of extinction because these species have limited possibilities to retreat and the warming has been faster in northern high latitudes than other regions Protected areas are likely to aid species in adapting to the changing climate by preserving high quality natural habitats where species can thrive. However, due to extensive land use and habitat degradation protection cannot always cover a sufficient amount of high quality habitat. In this case, habitat restoration can be the solution to improve habitat quality and availability, which can have positive effects on the ability of species to move and persist under climate change. The aim of this thesis is to shed light on how protected areas have been able to mitigate the negative effects of the current climate change. In addition, it studies the role of habitat quality in the processes of redistribution events. Lastly, the thesis evaluates how habitat enhancement by restoration affects the abundances of species threatened by wide-scale habitat loss and degradation. The focal species of the thesis are birds, owing to the extensive, long-term Finnish monitoring data which are unique even in a global perspective. In the first chapter, I study changes in abundance of the past five decades on the trailing range edge of northern and leading range edge of southern bird species. This study shows that protected areas help northern bird species maintain their abundances on the southern boundary of their current area of distribution, while aiding certain southern bird species spread to new territories on the northern boundary of their distribution area. This suggests that protected areas are able to slow down the northbound retreat of species, but also facilitate northward range expansions of southern species. The second chapter studies if the effect of conservation in mitigating climate driven changes observed in the first chapter increases with increasing coverage of the protected area network. The results show that in northern and central Finland the increasing protected area coverage in the landscape is indeed associated with communities that are more stable and less affected by climate driven changes. However, such effect was not found in southern Finland, where the protected area coverage was very low, and in fact could be too low to support detectable levels of community resilience against climate change. Populations and communities are shown to be more resilient to environmental changes when higher proportions of suitable high-quality habitat is available. Thus habitat quality could certainly explain the results gained in chapters I & II. The chapter III studies the effect of habitat quality on the occurrence of the white-backed woodpecker. Woodpeckers occupied more frequently the high-quality habitat patches than lower quality patches suggesting that colonization events are more and local extinctions less frequent on these sites. Thus, high-quality habitats seem to enhance the ability of species to move and persist and therefore, protection of these sites should be a priority under the redistributing outcome of climate change. Chapter IV shows that habitat quality can be further improved through restoration. Counteracting the overgrowth of wetlands rapidly increased the number of staging and breeding birds. Many waterbird species are threatened and declining due to eutrophication and overgrowth and the results show that wetland management can mitigate these negative developments. The thesis concludes that protecting high-quality habitats can mitigate climate change driven range and community changes. However, current trajectories of conservation seem to be inadequate to preserve the current biodiversity. Therefore, to meet the aims to prevent further biodiversity loss, extensive and rapid efforts to increase protected area coverage and connectivity are direly needed. The main conclusion of this thesis support these acts and the benefits this will have for preserving biodiversity in the future. Ilmastomuutoksella on todettu olevan huomattava vaikutus elinkirjoon. Sen tunnetuimpia seurauksia ovat levinneisyysaluemuutokset. Samanaikainen elinympäristöjen heikentyminen ja pirstoutuminen hankaloittaa lajien sopeutumista muuttuvaan ilmastoon. Mikäli lajit eivät pysty sopeutumaan tai siirtymään, niiden riski kuolla sukupuuttoon kasvaa. Etenkin pohjoiset lajit ovat vaarassa, sillä lämpeneminen on ollut nopeinta boreaalisella ja arktisella vyöhykkeellä ja näillä alueilla siirtymismahdollisuuksia rajoittavat jäämeri sekä kölivuoristo. Suojelualueiden on oletettu auttavan sopeutumaan ilmastonmuutokseen säilyttämällä korkealaatuisia elinympäristöjä, joissa lajit voivat menestyä. Laaja-alaisen elinympäristöjen laadun heikkenemisen vuoksi suojelu ei pysty välttämättä turvaamaan kohtuullista määrää korkealaatuisia elinympäristöjä. Tällöin elinympäristöjen kunnostaminen voi luoda lisää korkealaatuisia ympäristöjä, mikä voi puolestaan parantaa lajien kykyä siirtyä ja sopeutua. Väitöskirjani tarkoitus on tutkia ovatko suojelualueet kyenneet lieventämään ilmastomuutoksen epäedullisia vaikutuksia elinkirjoon. Tutkin, miten elinympäristön laatu vaikuttaa ilmastosta johtuviin levinneisyysaluemuutoksiin sekä onko kunnostuksella vaikutusta elinympäristöjen heikkenemisestä kärsivien lajien yksilömääriin. Väitöskirjani kohdelajeja ovat linnut, sillä suomalainen laaja ja pitkäjänteinen linnustonseuranta tarjoaa maailmanlaajuisesti ainutlaatuisen aineiston tutkia edellä mainittuja luonnon tapahtumaketjuja. Ensimmäisessä osatyössä tutkin viimeisen viiden vuosikymmenen aikana tapahtuneita runsausmuutoksia lintulajien levinneisyysalueiden reunoilla. Verrattuna suojelemattomiin alueisiin, suojelualueilla pohjoiset lintulajit säilyivät runsaampina levinneisyytensä eteläreunalla. Vastaavasti osa eteläisistä lajeista runsastui suojelualueilla enemmän kuin suojelemattomilla levinneisyysalueen pohjoisreunalla. Suojelualueet vaikuttavat hidastavan pohjoisten lajien vetäytymistä, mutta myös auttavan eteläisiä lajeja levittäytymään kohti pohjoista. Toisessa osatyössä tutkin, voimistuuko suojelualueiden ilmastovaikutusten ehkäisy suojelualueverkoston kattavuuden kasvaessa. Pohjois- ja Keski-Suomessa kattavampi suojelualueverkosto oli yhteydessä kasvaneeseen kykyyn puskuroida ilmastosta johtuvia lintuyhteisömuutoksia. Vastaavaa yhteyttä ei kuitenkaan havaittu Etelä-Suomessa, jossa suojelualueiden kattavuus oli hyvin alhainen, ja voi hyvinkin olla liian alhainen osoittaakseen merkittävää sietokykyä ilmastosta johtuvia yhteisömuutoksia vastaan. Lajien kestokyvyn ympäristömuutoksia vastaan on osoitettu kasvavan korkealaatuisten elinympäristöjen saatavuuden parantuessa. Siksi elinympäristön laatu voisi selittää havaitut suojelualueiden myönteiset vaikutukset. Tutkin tätä kolmannessa osatyössä valkoselkätikan osalta. Tikkojen havaitsemistodennäköisyys oli huomattavasti suurempi korkealaatuisissa kuin huonompilaatuisissa elinympäristöissä. Tulokset viittaavat siihen, että tikat asuttivat korkealaatuiset elinympäristöt huonompilaatuisia useammin ja vastaavasti hylkäsivät ne huonompilaatuisia harvemmin. Elinympäristön korkea laatu vaikuttaa siten parantavan tikkojen mahdollisuuksia siirtyä ja säilyä, ja näiden suojelun tulisi olla etusijalla ilmastonmuutoksen haittavaikutuksia torjuttaessa. Neljäs osatyö osoittaa, että elinympäristön laatua voidaan parantaa kunnostamalla. Kosteikkojen umpeenkasvun torjuminen kasvatti lintujen määriä nopeasti. Rehevöityminen ja umpeenkasvu uhkaavat monia vesilintuja, ja kosteikkojen kunnostuksella uhkaa voidaan torjua. Väitöskirjan johtopäätös on, että suojelemalla ja kunnostamalla korkealaatuisia elinympäristöjä voidaan lieventää ilmastomuutoksen aiheuttamia levinneisyysalue- ja yhteisömuutoksia. Nykyinen suojelutoimien laajuus on osoittautunut riittämättömäksi tavoitteessa ehkäistä elinkirjon väheneminen. Siksi tämän tavoitteen saavuttamiseksi tarvitaan laajoja ja nopeita toimia suojelualueverkoston kattavuuden ja kytkeytyneisyyden kasvattamiseksi. Väitöskirjani tulokset tukevat näitä toimia sekä niiden mukanaan tuomia hyötyjä elonkirjon säilyttämiseksi seuraaville sukupolville.