Reproductive Success Responses To Habitat Fragmentation In Eurasian Treecreepers

Siirretty Doriast

Data and code for manuscript: Increasing human environmental footprint does not lead to biotic homogenization of forest bird communities in northern USA

R-code and data for replicating statistical analyses used in the study: Increasing human environmental footprint does not lead to biotic homogenization of forest bird communities in northern USA. This study examined how forest loss and increased human domination in the state of Minnesota in the USA were associated with diversity of forest birds using bird count data

Conflicting objectives in production forests pose a challenge for forest management

Conflicts among different ecosystem services have been shown to be common and potentially exacerbated by management interventions. In order to improve the sustainability of natural resource use, the occurrence of these conflicts and the effects that management actions have on them need to be understood. We studied the conflicts between ecosystem services and the potential to solve them by management choices in boreal production forests. Our study area consisted of nearly 30,000 forest stands which were simulated for 50 years into the future under alternative management scenarios. The study included four ecosystem services – timber production, bilberry production, carbon storage, and pest regulation – and one biodiversity conservation objective defined as availability of deadwood resources. We 1) measured the conflicts among each pair of objectives, and 2) identified a compromise solution for each pairwise conflict defined as one which simultaneously minimizes the losses for both objectives. Our results show that conflicts between timber production and other objectives are typical, severe, and difficult to solve, while non-extractive benefits including biodiversity conservation can be more easily reconciled with each other. To mitigate the most severe conflicts in boreal forests, increased diversity in management regimes is required.peerReviewe

Increasing human environmental footprint does not lead to biotic homogenization of forest bird communities in northern USA

Studies have shown negative impacts of increased human pressures on biodiversity at local (alpha-diversity) and regional (gamma-diversity) scales. However, the diversity between local sites (beta-diversity) has received less attention. This is an important shortcoming since beta- diversity acts as a linkage between the local and regional scales. Decreased beta- diversity means that local sites lose their distinctiveness, becoming more similar to each other. This process is known as biotic homogenization. However, the mechanisms causing biotic homogenization have not been fully studied nor its impacts on different facets of biodiversity. We examined if land- use change due to human actions causes biotic homogenization of taxonomic, functional, and phylogenetic diversity in bird communities of forested habitats in the state of Minnesota, USA. We address if forest loss and increased human domination in a region were associated with decreased beta- diversity. Our results showed that elevated human pressure was not related to increased biotic homogenization in this study region. Effects of landscape change were incongruent among taxonomic, functional, and phylogenetic diversity. At all spatial scales, taxonomic diversity was unrelated to forest loss or human domination. Interestingly, increased human domination appeared to increase the functional beta- diversity of bird communities. This association was driven by a decrease in local diversity. Forest habitat loss was associated with de -creasing functional and phylogenetic diversity in local communities (alpha- diversity) and in regional species pool (gamma-diversity), but not in beta- diversity. We highlight the importance of considering multiple facets of biodiversity as their responses to human land- use is varied. Conservation significance of beta- diversity hinges on local and regional diversity responses to human land- use intensification, and organization of biodiversity should therefore be analyzed at multiple spatial scales.peerReviewe

Conspecific density drives sex-specific spatial wintertime distribution and hoarding behaviour of an avian predator

Useimmat tutkimukset lajinsisäisestä kilpailusta on tehty pesimäkaudella. Pohjoisilla leveysasteilla lajinsisäisen kilpailun kuitenkin odotetaan olevan erityisen voimakasta pesimäkauden ulkopuolella, kun sääolosuhteet ovat ankarat ja resursseja on tarjolla rajallisesti. Tässä tutkimuksessa tarkastelimme talvehtivien varpuspöllöjen (Glaucidium passerinum) ravinnonkeräämiskäyttäytymistä 15 vuoden ajalta. Lisäksi analysoimme sekä sukupuoli- että ikäkohtaista alueellista levittäytymistä suhteessa vaihtelevaan pääsaaliin (myyrien) runsauteen ja lajinsisäiseen tiheyteen. Huonoina myyrävuosina korkeampi lajinsisäinen tiheys vähensi varpuspöllöjen varastoiman saaliin kokonaismäärää, mikä voi johtua epäsuoran resurssikilpailun korkeista kustannuksista. Etäisyydet ruokavarastojen välillä olivat pidempiä silloin, kun lähimmät naapurit olivat naaraita, mikä viittaa alueellisen käyttäytymisen liittyvän sukupuolikohtaiseen kilpailuun. Naarasvarpuspöllöjen varastot sisälsivät kuitenkin enemmän saalista erityisesti silloin, kun lähin naapuri oli samaa sukupuolta. Yksilöt varastoivat enemmän saalista varpuspöllöpopulaation tiheyden kasvaessa. Saaliiden jakaminen useille varastopaikoille yhden sijasta voi auttaa vähentämään mahdollisia varkauksia pöllöpopulaation tiheyden ollessa suuri. Nämä tulokset yhdistettyinä viittaavat siihen, että suuri lajinsisäinen tiheys kärjistää sukupuolisidonnaista suoraa häirintäkilpailua (eikä pelkästään epäsuoraa resurssikilpailua), mikä puolestaan voi johtaa havaitsemaamme sukupuolikohtaiseen alueelliseen levittäytymiseen. Ravinnonkeräämis- ja häirintäkäyttäytymisen perusteella sukupuolikohtainen alueellinen levittäytyminen voi olla keino vähentää lajinsisäisen kilpailun voimakkuutta paikallisesti. Sillä voi olla myös kerrannaisvaikutuksia saalisyhteisöön.Most studies on intraspecific competition, i.e., competition among individuals of the same species, have been conducted during the breeding season. Yet, at northern latitudes, intraspecific competition is expected to be particularly strong under the harsh weather conditions of the non-breeding season with limited number of resources available per individual. We studied the food-hoarding behaviour of wintering Eurasian Pygmy Owls (Glaucidium passerinum) along with sex- and age-specific spatial distribution in relation to fluctuating main prey abundance (voles) and conspecific density using a 15-year dataset. In low vole abundance years, increasing conspecific density reduced the total prey number stored by an owl, suggesting high costs of exploitative competition. The distance between the stores of nearest neighbours was greater when both were females, suggesting that the spatial avoidance is driven by sex-specific competition. However, food stores of females had a larger amount of prey items, especially when the nearest neighbour was of the same sex. The number of stores hoarded by an owl increased with increasing conspecific densities. Distributing the prey items to multiple store-sites instead of one (shifting from larder-hoarding towards scatter-hoarding) can help to reduce the overall loss to potential pilfering when conspecific density is high. These results combined suggest that high conspecific density inflames sex-specific interference competition, rather than solely exploitative competition, and in turn drives the observed sex-specific spatial distribution. Adopting a sex-specific spatial distribution according to hoarding and aggressive behaviour can be a way to reduce the severity of intraspecific competition locally and could have cascading effects on the prey community.peerReviewe

Impacts of forestry on boreal forests : An ecosystem services perspective

Forests are widely recognized as major providers of ecosystem services, including timber, other forest products, recreation, regulation of water, soil and air quality, and climate change mitigation. Extensive tracts of boreal forests are actively managed for timber production, but actions aimed at increasing timber yields also affect other forest functions and services. Here, we present an overview of the environmental impacts of forest management from the perspective of ecosystem services. We show how prevailing forestry practices may have substantial but diverse effects on the various ecosystem services provided by boreal forests. Several aspects of these processes remain poorly known and warrant a greater role in future studies, including the role of community structure. Conflicts among different interests related to boreal forests are most likely to occur, but the concept of ecosystem services may provide a useful framework for identifying and resolving these conflicts.peerReviewe

Alder pollen in Finland ripens after a short exposure to warm days in early spring, showing biennial variation in the onset of pollen ripening

We developed a temperature sum model to predict the daily pollen release of alder, based on pollen data collected with pollen traps at seven locations in Finland over the years 2000–2014. We estimated the model parameters by minimizing the sum of squared errors (SSE) of the model, with weights that put more weight on binary recognition of daily presence or absence of pollen. The model results suggest that alder pollen ripens after a couple of warm days in February, while the whole pollen release period typically takes up to 4 weeks. We tested the model residuals against air humidity, precipitation and wind speed, but adding these meteorological features did not improve the model prediction capacity. Our model was able to predict the onset of pollen season with similar accuracy as models describing only the start of the pollen release period (average prediction error 8.3, median 5.0 days), while for the end of the pollen release period the accuracy of our predictions was not as good. We split the pollen data into odd and even years, and fitted our model separately to each half. Difference in the parameter values suggests a biennial behavior in the onset of pollen ripening, with almost two weeks of difference in the modeled starting date of the pollen development. Monte Carlo resampling of the observation data confirmed that the difference is not just a random anomaly in the data.peerReviewe

Using change trajectories to study the impacts of multi-annual habitat loss on fledgling production in an old forest specialist bird

The loss and subdivision of habitat into smaller and more spatially isolated units due to human actions has been shown to adversely affect species worldwide. We examined how changes in old forest cover during eight years were associated with the cumulative number of fledged offspring at the end of study period in Eurasian treecreepers (Certhia familiaris) in Central Finland. We were specifically interested in whether the initial level of old forest cover moderated this relation. We applied a flexible and powerful approach, latent growth curve modelling in a structural equation modeling (SEM) framework, to create trajectories describing changes in old forest cover through time, and studied how this change at both the territory core and landscape scales impacted fledging numbers. Our main finding was that at the territory core scale the negative impact of habitat loss on fledging numbers was lessened by the higher levels of initial forest cover, while no association was found at the landscape scale. Our study highlights a powerful, but currently under-utilised methodology among ecologists that can provide important information about biological responses to changes in the environment, providing a mechanistic way to study how land cover dynamics can affect species responses.peerReviewe