Spatial and temporal determinants of Finnish farmland bird populations

During the past decades agricultural intensification has caused dramatic population declines in a wide range of taxa related to farmland habitats, including farmland birds. In this thesis, I studied how boreal farmland landscape characteristics and agricultural land use affect the abundance and diversity of farmland birds using extensive field data collected by territory mapping of breeding farmland birds in various parts of Finland. My results show that the area and openness of agricultural areas are key determinants of farmland bird abundance and distribution. A landscape composition with enough open farmland combined with key habitats such as farmyards and wetland is likely to provide essential prerequisites for the occurrence of a rich farmland avifauna. In Finland, the majority of large areas suitable for open habitat specialists are located in southern and western parts of the country. However, the diversity of the species with an unfavourable conservation status in Europe (SPECs) had notable hotspot areas in northern and north-western agricultural areas. I found that in boreal agroecosystems farmland birds favour fields with springtime vegetative cover, especially agricultural grasslands and set-asides. Hence, in the spring cereal dominated Finnish agroecosystems it is the absence of field vegetation that may limit populations of many farmland bird species. It is likely that the decrease of crops providing vegetative cover in the spring, such as permanent grasslands, cultivated grass, and autumn-sown cereals, has greatly contributed to the declines of Finnish farmland birds. Grass crops have persistently declined in Finland as a consequence of specialization in crop production and the large-scale decline in livestock husbandry. Small-scale non-crop habitats, especially ditches and ditch margins, are also important for many bird species in the Finnish agroecosystems, but have dramatically declined during the last decades. A major problem for farmland bird conservation in Finland is the conflict between landscape structure and agricultural management. Areas with mixed and cattle farming are virtually absent from the large agricultural plains of southern and south-western Finland, where the landscape structure is more likely to be favourable for rich farmland bird assemblages. On the other hand, mixed and cattle farming is still rather frequent in northern and central parts of the country, where the landscape structure is not suitable for many farmland specialist birds requiring open landscapes. My results provide useful guidelines for farmland bird conservation, and imply that considerable attention needs to be paid to landscape factors when selecting areas for various conservational management actions, such as agri-environment schemes. Actions promoting the abundance of set-asides, grass crops, and ditches would markedly benefit Finnish farmland bird populations. Organic farming may benefit farmland birds, but it is not clear how general its beneficial effect is in boreal agroecosystems. The most urgent action aiming to preserve farmland biodiversity would be to support re-introducing and sustaining cattle farming by environmental subsidies. This would be especially beneficial in the southern parts of Finland, where the landscape characteristics and abundance of agricultural areas are most suitable for farmland birds and where cattle farming is currently rare.Maatalouden tehostuminen viime vuosikymmeninä on aiheuttanut laajamittaista maatalousluonnon köyhtymistä, ja myös peltolinnut ovat huomattavasti vähentyneet. Väitöskirjassani tutkin, miten boreaalisen maatalousympäristön maiseman ja peltojen käytön erityispiirteet vaikuttavat peltolinnuston runsauteen ja monimuotoisuuteen. Tutkimuksen aineistona käytettiin peltolinnuston kartoituslaskenta-aineistoa, jota on kerätty laajoilla alueilla ympäri Suomea. Tulokseni osoittavat, että maatalousmaiseman avoimuus ja laajuus ovat ensiarvoisen tärkeitä peltolinnuston runsaudelle ja levinneisyydelle. Monimuotoinen maisemakoostumus, jossa on riittävästi avointa peltoa ja lisäksi muita avainelinympäristöjä, kuten maatilojen piharakennuksia ja kosteikkoja, on peltolinnuston monimuotoisuudelle optimaalinen. Suomessa peltolinnustolle sopivimmat laajat peltoalueet ovat runsaimpia maan etelä-, lounais-, ja länsirannikon seuduilla. Sisämaan karjatalousvaltaiset alueet ovat myös tärkeitä, sillä alue soveltuu hyvin niille peltolintulajeille, joilla koko Euroopan laajuisesti menee huonosti. Tulosteni mukaan boreaalisessa maatalousympäristössä peltolinnut suosivat keväällä kasvipeitteisiä peltoja, ennen kaikkea nurmia ja kesantoja. Siten kevätviljavaltaisessa Suomessa kasvipeitteisten peltojen väheneminen karjatalouden vähenemisen myötä vaikuttaa olevan yksi keskeinen syy peltolinnuston taantumiseen. Myös viime vuosikymmeninä dramaattisesti vähentyneet avo-ojat ja pientareet ovat linnustolle tärkeitä. Peltolinnuston kannalta suurin ongelma Suomen maatalousympäristöissä on maantieteellinen ristiriita maiseman rakenteen ja maatalouden tuotantosuuntien välillä. Peltolinnuston monimuotoisuutta edistävä karjatalous on lähes hävinnyt Etelä- ja Lounais-Suomen laajoilta peltoaukeilta, joissa maiseman avoimuus suosii runsasta peltolinnustoa. Karjataloutta taas harjoitetaan runsaammin pohjoisempana ja idempänä, jossa taas maiseman rakenne ei ole riittävän avoin monimuotoiselle peltolintuyhteisölle. Tulokseni tarjoavat hyödyllisiä suuntaviivoja peltolinnuston hyvinvoinnin edistämiseksi. Maisematekijät olisi syytä ottaa huomioon erilaisten maatalousluonnolle hyödyllisten toimenpiteiden sijoittamisessa. Hyödyllisiin toimenpiteisiin kuuluvat monet maatalouden ympäristötuen toimenpiteet, kuten kesannointi. Tulosteni mukaan myös luonnonmukainen viljely hyödyttää ainakin kiurua ja töyhtöhyyppää. Parhaiten peltolinnuston tilaa voitaisiin kuitenkin kohentaa tukemalla karja- ja sekamaatalouden harjoittamista ja myöskin uudelleenkäynnistämistä. Linnuston kannalta erityisen hyödyllistä se olisi maan etelä- ja lounaisosien suurilla peltoalueilla, joilla karjatalous nykyisin on vähäistä

Three-toed Woodpecker cavities in trees : A keystone structural feature in forests shows decadal persistence but only short-term benefit for secondary cavity-breeders

Primary cavity-producers like woodpeckers are often considered as keystone species, because they produce nest sites also for several other cavity-nesting animals and, thus, maintain ecological webs of cavity-breeders. However, the detailed temporal dynamics of cavities and their lifetime occupancy rates and survival are not usually known which makes it difficult to assess the actual significance and full impact of primary cavity breeders. In this study, we monitored cavities in a large forest landscape, covering the full lifetime of cavities. We focused on a mature and old-growth forest specialist cavity-breeder, the Three-toed Woodpecker Picoides tri-dactylus. The data include the annual occupancy history of 655 old cavities of the Three-toed Woodpecker in 86 territories in a 170-km(2) area in southern Finland during 1987-2017. The study area included both managed and natural forest types. The median survival time of a cavity was 10 years, but there were significant differences between forest area types with a range of 7-13 years. The occupancy in all cavities was 21.3%, and the cavities were available for secondary cavity-breeders each year. There was a significant negative correlation between the occupancy and the age of the cavity. The first five years of a cavity were important for the total occupancy, and 86% of occupancies took place before the median age of the cavities. In cavities older than 15 years the occupancy was only 7%. The pattern was similar in all types of forests. Our results show that cavities made by Three toed Woodpeckers have rather long lifespan but also that their active use by other cavity-breeding species is restricted mostly to few years only. The result indicates that new, fresh cavities are needed continuously in a forest landscape, in order to maintain the role that Three-toed Woodpecker has as a keystone species.Peer reviewe

Nest tree characteristics of the old-growth specialist Three-toed Woodpecker Picoides tridactylus

The Three-toed Woodpecker Picoides tridactylus is a mature and old-growth forest specialist but how the species uses trees for nesting in its breeding sites and whether cavity trees are a critical habitat feature is poorly known. We studied the nest tree characteristics of the species in a 170-km(2) area in southern Finland during 1987-2016. The data included 538 nest trees of eight different species and 665 nest cavities in 86 territory areas. Norway spruce Picea abler was the predominant nest tree comprising 71% of all nest trees. Proportionally, deciduous nest trees were more common in moist forests on mineral soils and conifer nest trees more common in spruce swamps. The majority of nest trees (85%) were dead or decaying trees; higher numbers of dead deciduous nest trees were recorded than dead conifer trees. The mean diameter of a nest tree at diameter at breast height (DBH) was 29.4 cm and the mean height of a cavity hole was 5.1 m; size and height were significantly positively correlated. The proportion of deciduous nest trees was significantly higher (45%) in natural forests compared with other areas subjected to variable amounts of forest management, where the respective proportion was only 9-17%. In addition, cavity holes were significantly higher in natural forests than in managed ones. In general, the results highlight the substantial flexibility in nest tree use but also the importance of large dead and decaying trees (including deciduous trees) as nest cavity sites for the species. Spruce swamps can be considered as key nesting habitats in managed forest landscapes.Peer reviewe

Sisämaan seurantapyynti 1987-2021: Yleisimpien varpuslintujen kannakehitys, poikastuotto ja elossasäilyvyys

Non peer reviewe

Nest tree characteristics of the Lesser Spotted Woodpecker (Dendrocopos minor) in boreal forest landscapes

Tree cavities, and especially cavities made by woodpeckers, are important microhabitats in forest ecosystems. However, the properties of woodpecker nest trees and cavities are poorly known even in boreal areas where most tree cavities are made by woodpeckers. We studied the nest tree characteristics of the Lesser Spotted Woodpecker (Dendrocopos minor) in a 170-km(2) forest-dominated area in southern Finland during 1987-2018. The data included 97 nest trees with 106 nest cavities in five deciduous tree species. During the study period, more than one nest cavity (2-3) was excavated in 7% of all cavity trees. Nests were found in three forest types, but the proportions of nest tree species differed between them. Birch (Betula spp.) was the most common nest tree species with 40% of nests. Nest trees were either dead (79%) or decaying (21%), and the majority (69%) had a broken top. The mean diameter at breast height (DBH) of a nest tree was 24.7 cm and the mean height of a cavity hole was 3.3 m; size and height were significantly positively correlated. The mean ratio of cavity height in relation to the respective nest tree height was 0.49, and did not depend on the nest tree condition. The results highlight the importance of dead and decaying deciduous trees as nest cavity sites for this small woodpecker species. Provision of suitable cavity trees during forest management is important to maintain breeding and cavity building opportunities for the Lesser Spotted Woodpecker in managed forests.Peer reviewe

Todellisuuden tutkimiseen tarvitaan vain yhtä tiedettä

Vuosisatojen ajan akateeminen yhteis&ouml; on jakautunut jyrk&auml;sti luonnontieteisiin ja humanistisiin tieteisiin. Keinotekoisesti yll&auml;pidetty jako on hidastanut tieteen kehityst&auml; ja saanut usein avoimen vihamielisi&auml; ja poliittisia ulottuvuuksia. Erilaisista n&auml;k&ouml;kulmistaan, selitystavoistaan ja menetelmist&auml;&auml;n huolimatta luonnontieteet ja ihmistieteet tutkivat samaa todellisuutta. Siksi tieteenaloja ei pit&auml;isi n&auml;hd&auml; kesken&auml;&auml;n kilpailevina vaan toisiaan t&auml;ydent&auml;vin&auml;. Ristiriidat johtuvat aina tutkijoista, eiv&auml;t koskaan tieteist&auml;. Onneksi tiede korjaa itse&auml;&auml;n, ja muutosten tuuli puhaltaa akateemisessa maailmassa.</p

Variation in body condition of songbirds during breeding season in relation to sex, migration strategy and weather

Animal body reserves are often linked with demographic parameters such as breeding success and survival. During breeding season individuals face a trade-off between maintaining body reserves and investing in reproduction. Factors influencing the body reserves of species during breeding season are poorly understood. In this study, we used long-term trapping data from Finnish Constant Effort Sites program to evaluate the impact of sex, migration behaviour, and weather on body reserve index (BRI) of old and young birds during breeding season in 20 species. Our main interest was to study how variation in weather conditions influences the BRI of breeding passerine birds. Weather variables did not explain BRI of adults. However, we found that BRI of young birds was weakly negatively connected with mean temperature, but this may have low biological importance. BRI of adult males increased towards the end of August, but female BRI showed a seasonal decline throughout June and July. Breeding females face the peak in physiological stress later thanmales, probably because females lay eggs, and often invest more in incubation and brood rearing thanmales. The seasonal decline caused females to have lower BRI thanmales at the end of the breeding season. This can cause females to be less prepared for the approaching autumnmigration thanmales. Our findings suggest that there are sex-specific changes in BRI during the breeding season, whichmay have carryover effects on other life history events.Peer reviewe

A state-of-the-art review on birds as indicators of biodiversity : Advances, challenges, and future directions

The current loss of biodiversity has been broadly acknowledged as the main cause of ecosystem change. To halt this trend, several international agreements have been made, and various biodiversity metrics have been developed to evaluate whether the targets of these agreements are being met. The process of developing good indicators is not trivial. Indicators should be able to synthesize and communicate our current knowledge, but they also need to meet both scientific and practical criteria. Since it would not be practical to monitor all species, indicators are mainly built on the monitoring of some well-known taxa, such as birds. Here we systematically review the wide spectrum of bird biodiversity indicators (hereafter indicators) available to: i) evaluate recent methodological advances; ii) identify current knowledge gaps jeopardizing indicator interpretation and use in guiding decision-making; and iii) examine challenges in their applicability across different spatial and temporal contexts. We pay particular attention to indicator characteristics such as site and species selection, spatial, seasonal and habitat coverage, and statistical issues in developing indicators and tools to tackle them, to provide specific recommendations for the future construction of indicators. Several methodological advances have recently been made to enhance the process of indicator development, including multiple ways to select sites and species to increase their robustness. However, we found that there are strong spatial, seasonal and habitat biases among the selected indicators. Most of them are from Europe, using mainly census data from the breeding season and typically covering farmland and forest habitats. The major challenges that we detected in their applicability were related to the modelling of the statistical uncertainty associated to the indicator. We recommend the use of quantitative methods in site and species selection procedures whenever possible. Current indicators should be expanded to areas outside Europe and to less studied habitats and should not neglect monitoring work outside the breeding season. Time-series analyses studying temporal trends and using multi-species data should in general account for temporal autocorrelation as well as for phylogenetic correlation. Multi-species hierarchical models are a good alternative for analysing and constructing indicators, but they need to include annual random effects allowing for unexplained annual variation in the average status of the community, i.e. the indicator target. Despite methodological and context-specific differences in the indicators reviewed, most of them seem to highlight the urgent need of devising strategic climate and conservation policies to improve the status and trends of biodiversity.Peer reviewe

Vesilintuseurannan tulokset 2023

Vesilintulaskentojen päätavoitteena on seurata pesimäkantojen muutoksia ja selvittää sorsien vuotuinen lisääntymistulos erityyppisillä vesillä ja eri puolilla Suomea. Tietoja tarvitaan mm. vesilintujen elinympäristöjen hoidon suunnitteluun ja metsästyksen mitoittamiseen sekä vesiluonnon monimuotoisuuden seurantaan. Vesilintuseurantaa koordinoivat Luonnonvarakeskus ja Luonnontieteellinen keskusmuseo, ja laskennoista vastaavat vapaaehtoisesti metsästäjät ja lintuharrastajat. Seurannan 16 lajista suurin osa on taantunut pitkällä aikavälillä. Runsain riistasorsamme sinisorsa on pitkällä aikavälillä runsastunut, mutta kanta on kääntynyt laskuun viimeisen kymmenen vuoden aikana. Vuonna 2023 useimpien riistavesilintujen parimäärät olivat melko lähellä vuoden 2022 tasoa. Laulujoutsenen kannan pitkäaikainen kasvu vaikuttaa viime vuosina kääntyneen laskuun. Sinisorsan ja haapanan poikastuotot olivat viime vuotta heikompia, mutta telkällä viime vuoden tasolla. Tavin poikastuotto oli hieman edellisvuotta parempi. Sinisorsan, tavin ja telkän parikohtainen poikastuotto on pitkällä aikavälillä heikentynyt, mutta viimeisen kymmenen vuoden aikana ei ole tilastollisesti merkitseviä muutoksia. Kuitenkin haapanan parikohtainen poikastuotto on tänä aikana kasvanut. Vesilintukannat ovat pitkällä aikavälillä taantuneet sekä rehevillä että karuilla vesillä, mutta rehevien vesistöjen linnut ovat taantuneet karujen vesien linnustoa jyrkemmin. Viimeisen kymmenen vuoden aikana karuilla vesillä lintujen kannankehitys on ollut vakaata, kun taas taantuma on yhä jatkunut rehevillä vesistöillä