Selecting the best:Interspecific and age-related diet differences among sympatric steppe passerines

Parental food provisioning is crucial for the growth and survival of offspring.Growth rate depends on food quality and food supplied to offspring may differ from what adults use for their own.In the case of steppe passerine birds,detailed characterization on nestling dietary composition,as well as prey choice and resource partitioning among species,is a pending subject.Dietary differences between nestlings and adults remain also largely unexplored.By using faecal DNA metabarcoding,we described the diet of nestlings and adults of five shrub-steppe passerine species over the 2017–2019 breeding seasons in central Spain.We also monitored arthropod availability in the field to assess dietary selection.We expected interspecific dietary differences to limit competition for food resources among sympatric species,as well as parental selection of high quality prey for nestlings.We also predicted age-related differences,with nestlings being fed nutrient-rich prey more frequently than adults.The main arthropod orders provisioned to nestlings were Orthoptera,Julida,Araneae and Lepidoptera.Nestlings of the different species showed high interspecific diet overlap,indicating both a coincidence in growth needs among bird species and no or little limitation of the most profitable resources during the breeding season.Adults of all species showed higher diet richness than nestlings,and age-related differences in prey composition were mainly driven by the selection of the most easily digestible,larger protein-and calcium-rich prey for nestlings,which may favour their rapid growth,and avoiding highly sclerotized and less nutritional prey such as ants.Our study sheds light on the basic ecology and conservation of these declining steppe birds,indicating that interspecific competition may not be a major factor during the breeding season.Given the current global decline of arthropods,further long-term research would be necessary,along with the implementation of effective conservation measures that ensure a sufficient availability of resources identified as key prey in the diet of steppe bird nestlings.

National Forest Inventories capture the multifunctionality of managed forests in Germany

Background:Forests perform various important ecosystem functions that contribute to ecosystem services.In many parts of the world,forest management has shifted from a focus on timber production to multi-purpose forestry,combining timber production with the supply of other forest ecosystem services.However,it is unclear which forest types provide which ecosystem services and to what extent forests primarily managed for timber already supply multiple ecosystem services.Based on a comprehensive dataset collected across 150 forest plots in three regions differing in management intensity and species composition,we develop models to predict the potential supply of 13 ecosystem services.We use those models to assess the level of multifunctionality of managed forests at the national level using national forest inventory data.Results:Looking at the potential supply of ecosystem services,we found trade-offs(e.g.between both bark beetle control or dung decomposition and both productivity or soil carbon stocks)as well as synergies(e.g.for temperature regulation,carbon storage and culturally interesting plants)across the 53 most dominant forest types in Germany.No single forest type provided all ecosystem services equally.Some ecosystem services showed comparable levels across forest types(e.g.decomposition or richness of saprotrophs),while others varied strongly,depending on forest structural attributes(e.g.phosphorous availability or cover of edible plants)or tree species composition(e.g.potential nitrification activity).Variability in potential supply of ecosystem services was only to a lesser extent driven by environmental conditions.However,the geographic variation in ecosystem function supply across Germany was closely linked with the distribution of main tree species.Conclusions:Our results show that forest multifunctionality is limited to subsets of ecosystem services.The importance of tree species composition highlights that a lack of multifunctionality at the stand level can be compensated by managing forests at the landscape level,when stands of complementary forest types are combined.These results imply that multi-purpose forestry should be based on a variety of forest types requiring coordinated planning across larger spatial scales.

Functional group richness increases multifunctionality in intensively managed grasslands

Background:Agricultural yields have increased continuously over the last few decades.However,a focus solely on production can harm the environment.Diversification of agriculture has been suggested to increase production and sustainability.Biodiversity experiments showed positive effects on ecosystems and productivity.However,application of these results to intensively managed grasslands has been questioned due to differences in plant species and management regimes.Research on whether diversity can benefit multifunctionality,that is,an integrated index of multiple ecosystem functions,under intensive management,is still scarce.Methods:To address this,we manipulated plant species richness from one to six species spanning three functional groups(legumes,herbs,and grasses)in intensively managed multispecies grassland leys and examined seven ecosystem functions.Results:We found that multifunctionality increased with functional group and species richness.Legume+herb mixtures showed high multifunctionality,while grass monocultures and mixtures with high proportions of grasses had low multifunctionality.Different plant species and plant communities drove different ecosystem functions.Legumes and herbs improved productivity and water availability,while grasses enhanced invasion resistance.These results indicate that multifunctionality and individual ecosystem functions can be promoted through targeted combinations of plants with complementary ecological traits.Conclusions:Plant diversity can improve multifunctionality also under intensive management,potentially benefitting agroeconomics and sustainability.

Seasonal variation and host sex affect bat–bat fly interaction networks in the Amazonian savannahs

Bats are the second-most diverse group of mammals in the world,and bat flies are their main parasites.However,significant knowledge gaps remain regarding these antagonistic interactions,especially since diverse factors such as seasonality and host sex can affect their network structures.Here,we explore the influence of such factors by comparing species richness and composition of bat flies on host bats,as well as specialization and modularity of bat–bat fly interaction networks between seasons and adult host sexes.We captured bats and collected their ectoparasitic flies at 10 sampling sites in the savannahs of AmapáState,northeastern region of the Brazilian Amazon.Despite female bats being more parasitized and recording greater bat fly species richness in the wet season,neither relationship was statistically significant.The pooled network could be divided into 15 compartments with 54 links,and all subnetworks comprised>12 compartments.The total number of links ranged from 27 to 48(for the dry and wet seasons,respectively),and female and male subnetworks had 44 and 41 links,respectively.Connectance values were very low for the pooled network and for all subnetworks.Our results revealed higher bat fly species richness and abundance in the wet season,whereas specialization and modularity were higher in the dry season.Moreover,the subnetwork for female bats displayed higher specialization and modularity than the male subnetwork.Therefore,both seasonality and host sex contribute in different ways to bat–bat fly network structure.Future studies should consider these factors when evaluating bat–bat fly interaction networks.

Assessing mowing intensity:A new index incorporating frequency,type of machinery,and technique

Background:Only a few decades ago,colorful,small-scale,heterogeneous,and species-rich hay meadows or extensive pastures were common,but have often been replaced by species-poor,uniform,large-scale multicut meadows.Technological advancements and improved efficiency in grassland management have come at the cost of biodiversity.Methods:In Germany,150 grassland plots have been investigated since 2006.Using these extensive data,we propose a new compound index for estimating the site-specific mowing intensity in order to facilitate assessment of the impact of mowing intensity on biodiversity and ecosystem processes.Our index integrates the various qualitative components of mowing machine type,mowing height and use of a conditioner,with the annual number of cuts.Results:The newly proposed index achieves a much finer gradation of mowing intensity compared to the previous quantification based on the number of cuts only.Furthermore,a decrease in plant and arthropod species was observed at higher mowing intensity.Conclusions:The proposed mowing intensity index offers enhanced precision in calculations and can easily be integrated into assessments of land-use intensity in grasslands.Further,it could serve as a basis for providing subsidies to farmers,who adopt low-impact mowing practices.

Frugivory and seed dispersal in the Galápagos:what is the state of the art?

The Galápagos are considered a model oceanic archipelago,with unique flora and fauna currently threatened by alien invasive species.Seed dispersal is an important ecosystem function with consequences for plant population dynamics and vegetation structure.Hence,understanding the seed dispersal abilities of the assemblages of frugivores will inform scientists and managers of the dynamics of plant invasions and improve management planning.Here we provide the first comprehensive review of published information on frugivory and animal seed dispersal in the Galápagos.We collected data from a variety of sources,including notes of the first naturalist expeditions,gray literature available only in Galápagos collections,and peer-reviewed journal articles.Plant–animal frugivorous interactions were retrieved from 43 studies and compiled into an interaction matrix describing 366 unique interactions.Most studies focused on fruit consumption as a driving force for natural selection,but seed fate was seldom considered.Although most(71%)of the interactions involved native plants,more than one-quarter(28%)involved introduced species.Interactions involving birds are considerably more common than those of reptiles and mammals,probably reflecting a research bias towards birds.Despite the historical importance of the archipelago as the laboratory for evolutionary and ecological research,understanding of its seed dispersal systems is limited.We end the review by suggesting 3 priority areas of research on frugivory and seed dispersal in the Galápagos:(i)target research to close knowledge gaps;(ii)the use of a network approach to frame seed dispersal at the community level;and(iii)evaluation of the effect of seed dispersal as a selective pressure acting upon plants and frugivores.Finally,the output of this research has to be properly delivered to the Galápagos National Park Services to help increase management effectiveness.