Genetic differentiation between insular and continental populations of migratory and resident warblers, the Great Reed Warbler Acrocephalus arundinaceus and the Cetti's Warbler Cettia cetti Journal of Ornithology

[EN] Island populations are frequently smaller than continental populations, have lower genetic diversity, are more inbred and show genetic differentiation from the mainland ones. However, sufficient numbers of immigrants may reduce the differentiation of insular populations and moderate the effects of genetic drift. In this study, we compared insular and continental populations of Cetti¿s Warbler Cettia cetti and Great Reed Warbler Acrocephalus arundinaceus. We assessed the degree of genetic differentiation between insular and continental birds, their demographic history and genetic diversity. We compared the results, taking into account the differences in migration strategy and morphology of the two warblers. We found slightly lower genetic diversity in the insular populations than in the continental birds, possibly because of the lower population size or reduced immigration. The genetic differentiation between island and mainland birds was low, but higher in Cetti¿s Warbler than in the Great Reed Warbler, suggesting differences in the species¿ capability of crossing the sea. We found evidence for a past bottleneck in both the insular and continental populations of Cetti¿s Warbler, while for the Great Reed Warbler we found no signs of past population reductions. A high dispersal capability of the Great Reed Warbler may have allowed high gene flow, which may explain the observed interspecific differences in the demographic history of the Great Reed Warbler and Cetti¿s Warbler.We acknowledge M. Rebassa, H. Rguibi-Idrissi, M. Marin, J. Gomez, Santi, Luis, Kames and family and many others, who have helped us with the fieldwork. We would also like to thank the authorities of the Marjal de Pego-Oliva Natural Park, the S'Albufera de Mallorca Natural Park, the Consejeria de medio Ambiente y Desarrollo Rural de Castilla-La Mancha, the Servei de Conservacio de la Biodiversitat de la Generalitat Valenciana and the Haut Commissariat aux Eaux et Forets et a la lutte contre la desertification de Rabat, Morocco for providing the facilities to work in protected areas and for the relevant permits. We are grateful to M. Serra and the researchers and Ph.D. students of the Laboratory of Evolutionary Ecology (Institute Cavanilles of Biodiversity and Evolutionary Biology University of Valencia), for providing a laboratory for DNA extraction. This study has been partly financed by projects CGL2005-02041/BOS and CGL201021933-0O2-02 of the Spanish Ministry of Science and Innovation and by the University of Oulu. F. Ceresa was supported by an Atraent talent grant from the University of Valencia.Ceresa, F.; Belda, E.; Kvist, L.; Kajanus, M.; Monrós González, JS. (2018). Genetic differentiation between insular and continental populations of migratory and resident warblers, the Great Reed Warbler Acrocephalus arundinaceus and the Cetti's Warbler Cettia cetti Journal of Ornithology. Journal of Ornithology (Online). 159(3):703-712. https://doi.org/10.1007/s10336-018-1543-2S703712159

Titmice are a better indicator of bird density in Northern European than in Western European forests

Publisher Copyright: © 2022 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.Population sizes of many birds are declining alarmingly and methods for estimating fluctuations in species’ abundances at a large spatial scale are needed. The possibility to derive indicators from the tendency of specific species to co-occur with others has been overlooked. Here, we tested whether the abundance of resident titmice can act as a general ecological indicator of forest bird density in European forests. Titmice species are easily identifiable and have a wide distribution, which makes them potentially useful ecological indicators. Migratory birds often use information on the density of resident birds, such as titmice, as a cue for habitat selection. Thus, the density of residents may potentially affect community dynamics. We examined spatio-temporal variation in titmouse abundance and total bird abundance, each measured as biomass, by using long-term citizen science data on breeding forest birds in Finland and France. We analyzed the variation in observed forest bird density (excluding titmice) in relation to titmouse abundance. In Finland, forest bird density linearly increased with titmouse abundance. In France, forest bird density nonlinearly increased with titmouse abundance, the association weakening toward high titmouse abundance. We then analyzed whether the abundance (measured as biomass) of random species sets could predict forest bird density better than titmouse abundance. Random species sets outperformed titmice as an indicator of forest bird density only in 4.4% and 24.2% of the random draws, in Finland and France, respectively. Overall, the results suggest that titmice could act as an indicator of bird density in Northern European forest bird communities, encouraging the use of titmice observations by even less-experienced observers in citizen science monitoring of general forest bird density.Peer reviewe

Do large-scale associations in birds imply biotic interactions or environmental filtering?

Aim There has been a wide interest in the effect of biotic interactions on species' occurrences and abundances at large spatial scales, coupled with a vast development of the statistical methods to study them. Still, evidence for whether the effects of within-trophic-level biotic interactions (e.g. competition and heterospecific attraction) are discernible beyond local scales remains inconsistent. Here, we present a novel hypothesis-testing framework based on joint dynamic species distribution models and functional trait similarity to dissect between environmental filtering and biotic interactions. Location France and Finland. Taxon Birds. Methods We estimated species-to-species associations within a trophic level, independent of the main environmental variables (mean temperature and total precipitation) for common species at large spatial scale with joint dynamic species distribution (a multivariate spatiotemporal delta model) models. We created hypotheses based on species' functionality (morphological and/or diet dissimilarity) and habitat preferences about the sign and strength of the pairwise spatiotemporal associations to estimate the extent to which they result from biotic interactions (competition, heterospecific attraction) and/or environmental filtering. Results Spatiotemporal associations were mostly positive (80%), followed by random (15%), and only 5% were negative. Where detected, negative spatiotemporal associations in different communities were due to a few species. The relationship between spatiotemporal association and functional dissimilarity among species was negative, which fulfils the predictions of both environmental filtering and heterospecific attraction. Main conclusions We showed that processes leading to species aggregation (mixture between environmental filtering and heterospecific attraction) seem to dominate assembly rules, and we did not find evidence for competition. Altogether, our hypothesis-testing framework based on joint dynamic species distribution models and functional trait similarity is beneficial in ecological interpretation of species-to-species associations from data covering several decades and biogeographical regions.Peer reviewe

Ecological and evolutionary consequences of selective interspecific information use

Recent work has shown that animals frequently use social information from individuals of their own species as well as from other species; however, the ecological and evolutionary consequences of this social information use remain poorly understood. Additionally, information users may be selective in their social information use, deciding from whom and how to use information, but this has been overlooked in an interspecific context. In particular, the intentional decision to reject a behaviour observed via social information has received less attention, although recent work has indicated its presence in various taxa. Based on existing literature, we explore in which circumstances selective interspecific information use may lead to different ecological and coevolutionary outcomes between two species, such as explaining observed co-occurrences of putative competitors. The initial ecological differences and the balance between the costs of competition and the benefits of social information use potentially determine whether selection may lead to trait divergence, convergence or coevolutionary arms race between two species. We propose that selective social information use, including adoption and rejection of behaviours, may have far-reaching fitness consequences, potentially leading to community-level eco-evolutionary outcomes. We argue that these consequences of selective interspecific information use may be much more widespread than has thus far been considered

Interspecific associations and interactions in birds:ecological and evolutionary consequences, and conservation implications

Abstract Current environmental changes lead to declines in species abundances globally, creating a need for understanding mechanisms shaping community composition. Species interactions are a fundamental force in shaping species distributions affecting, for example, the functionality of entire multispecies networks. Still, interactions are poorly integrated in current estimation of community dynamics. Examining correlations in species abundances, such as species pairwise aggregations or segregations, may provide an opportunity to understand species interactions, and novel developments in Joint Species Distribution Models (JSDMs) facilitate the derivation of these associations. My aim is to expand the current understanding of species associations and interactions at large spatial scales, specifically examining (I) can species associations be used to develop practical tools for estimating species abundances in communities, (II) do species interactions leave a signal in community composition, and (III) what ecological and evolutionary consequences may selective interspecific information use have at the community level. I derived species associations from Finnish and French breeding bird data, covering a large spatial and temporal range, using a JSDM (I, II). Furthermore, I used linear models to examine the sign of species interactions in community composition (II). I used a simulation model to examine the ecological and evolutionary consequences of selective social information use. The results suggest that (I) the abundance of tit species could be used as an efficient ecological indicator for the total density of other forest birds, (II) environmental filtering and positive species associations leave a stronger sign than competition at large spatial scales on bird community composition, and (III) (selective) social information use may lead to trait divergence, convergence or a coevolutionary arms race between species. Overall, these results indicate that species interactions may have immediate and long-lasting community-level effects, and accounting for them is critical in estimating community dynamics at large spatial scales. Thus, interaction networks may have profound effects on species’ responses to changing environments and should not be overlooked when planning conservation efforts.Tiivistelmä Ympäristönmuutoksen aiheuttama luontokato on yksi ihmiskunnan tärkeimmistä haasteista. Lajienväliset vuorovaikutukset vaikuttavat eliöyhteisöjen rakenteeseen. Samanaikaisesti ympäristömuutokset muokkaavat yhteisöjen rakennetta ja lajienvälisiä vuorovaikutuksia sekä suoraan että lajien runsauksien kautta. Tästä huolimatta lajienvälisten vuorovaikutusten ekologiset ja evolutiiviset seuraukset muun muassa yhteisön rakenteeseen tunnetaan puutteellisesti. Luontokadon ymmärtämiseksi ja suojelutoimien kohdentamiseksi on erittäin tärkeää selvittää, kuinka lajienväliset vuorovaikutukset muokkaavat eliöyhteisöjä ja niiden kykyä sopeutua ympäristömuutoksiin laajalla ilmasto- ja aikagradientilla. Väitöskirjassani tutkin lajienvälisten vuorovaikutusten ekologisia ja evolutiivisia seurauksia, sekä niiden vaikutuksia yhteisötasolla, etenkin (I) voidaanko lajienvälisten runsauksien korrelaatioita käyttää apuna yhteisönrunsautta mittaavien käytännönmenetelmien kehittämisessä, (II) selittävätkö lajienväliset vuorovaikutukset vai ympäristötekijät yhteisön rakennetta, ja (III) kuinka yleistä valikoiva lajienvälinen informaationkäyttö on ja mitkä ovat sen ekologisia ja evolutiivisia seurauksia. Johdin lajienvälisten runsauksien korrelaatiot laajan maantieteellisen ja ajallisen mittakaavan kattavista Suomen ja Ranskan pesimälintuaineistoista käyttämällä yhteisölevinneisyysmalleja (I, II). Tutkin lajienvälisten vuorovaikutusten ja ympäristötekijöiden vaikutusta lajienvälisiin runsauden korrelaatioihin lineaarisilla malleilla (II). Valikoivan lajienvälisen informaationkäytön yleisyyttä, sekä sen ekologisia ja evolutiivisia seurauksia tarkastelin simulaatiomallin avulla (III). Väitöskirjani osoittaa, että (I) tiaisten yhteisrunsaus voi toimia pesivien metsälintujen runsauden indikaattorina boreaalisissa metsissä, (II) Suomen ja Ranskan lintuyhteisöissä negatiivisten lajienvälisten vuorovaikutusten sijaan ympäristötekijät ja positiiviset vuorovaikutukset selittivät lajienvälisten runsauksien korrelaatioita, ja (III) lajienvälinen valikoiva informaationkäyttö voi johtaa lajien fenotyyppiseen eriytymiseen, lähentymiseen tai asevarustelukierteeseen, millä kaikilla on myös yhteisötason seuraamuksia. Väitöskirjani osoittaa lajienvälisten vuorovaikutusverkostojen huomioimisen tärkeyden suojelubiologisessa päätöksenteossa