15 research outputs found
Natal legacies cause social and spatial marginalization during dispersal
Earlyâlife experiences can drive subsequent variation in social behaviours, but how differences among individuals emerge remains unknown. We combined experimental manipulations with GPSâtracking to investigate the pathways through which developmental conditions affect social network position during the early dispersal of wild red kites (Milvus milvus). Across 211 juveniles from 140 broods, lastâhatched chicksâthe least competitiveâhad the fewest number of peer encounters after fledging. However, when food supplemented, they had more encounters than all others. Using 4425 birdâdays of GPS data, we revealed that this was driven by differential responses to competition, with less competitive individuals naturally spreading out into marginal areas, and clustering in central foraging areas when food supplemented. Our results suggest that earlyâlife adversities can cause significant natal legacies on individual behaviour beyond independence, with potentially farâreaching consequences on the social and spatial structure of animal populations
Connectedness of habitat fragments boosts conservation benefits for butterflies, but only in landscapes with little cropland
Context Global change pressures (GCPs) imperilspecies and associated ecosystem functions, but studies investigating interactions of landscape-scale pressures
remain scarce. Loss of species-rich habitat and agricultural expansion are major threats for biodiversity, but if or how these factors interactively determine
community-level shifts and conservation outcomes remains unclear.
Objectives We tested whether matrix simplification (dominance of cropland) and reduced connectivity (i.e. landscape-scale habitat loss) either additively,
synergistically or antagonistically cause community shifts in butterflies, a group of high conservation relevance.
Methods We surveyed butterflies on 30 small calcareous grassland fragments (<1 ha) in Central Germany, representing independent gradients in grassland
connectivity (an index combining grassland area and proximity), and matrix quality (landscape proportion of cropland). Using proportional odds logistic regression, we assessed whether connectivity and matrix quality interactively altered the distribution of Red List statuses, and assessed effects of local scale management (mowing, grazing, short-term abandonment).
Results We found synergistic, conservation relevant effects: Connectivity boosted the proportion of redlisted species from 20 to 52% in crop land poor
landscapes, but not in crop land rich landscapes, particularly driven by endangered and critically endangered species. Grazed sites had the lowest
species richness, abundance, and proportions of conservation
relevant butterflies.
Implications Mitigation measures targeting one landscape-scale pressure only may be inefficient, particularly for red-listed species. Increasing habitat
connectivity bolsters butterfly communities and potential pollination services, but only if accompanied by measures to soften the matrix. Hence, halting biodiversity
losses needs better understanding and implementation of complex conservation measures at the landscape scale
Saproxylic species are linked to the amount and isolation of dead wood across spatial scales in a beech forest
ContextDead wood is a key habitat for saproxylicspecies, which are often used as indicators of habitatquality in forests. Understanding how the amount andspatial distribution of dead wood in the landscapeaffects saproxylic communities is therefore importantfor maintaining high forest biodiversity.ObjectivesWe investigated effects of the amountand isolation of dead wood on the alpha and betadiversity of four saproxylic species groups, with afocus on how the spatial scale influences results.MethodsWe inventoried saproxylic beetles, wood-inhabiting fungi, and epixylic bryophytes and lichenson 62 plots in the Sihlwald forest reserve in Switzer-land. We used GLMs to relate plot-level speciesrichness to dead wood amount and isolation on spatialscales of 20â200 m radius. Further, we used GDMs todetermine how dead wood amount and isolationaffected beta diversity.ResultsA larger amount of dead wood increasedbeetle richness on all spatial scales, while isolation hadno effect. For fungi, bryophytes and lichens this wasonly true on small spatial scales. On larger scales ofour study, dead wood amount had no effect, whilegreater isolation decreased species richness. Further,we found no strong consistent patterns explaining betadiversity
Extinction filters mediate the global effects of habitat fragmentation on animals
Habitat loss is the primary driver of biodiversity decline worldwide, but the effects of fragmentation (the spatial arrangement of remaining habitat) are debated. We tested the hypothesis that forest fragmentation sensitivityâaffected by avoidance of habitat edgesâshould be driven by historical exposure to, and therefore speciesâ evolutionary responses to disturbance. Using a database containing 73 datasets collected worldwide (encompassing 4489 animal species), we found that the proportion of fragmentation-sensitive species was nearly three times as high in regions with low rates of historical disturbance compared with regions with high rates of disturbance (i.e., fires, glaciation, hurricanes, and deforestation). These disturbances coincide with a latitudinal gradient in which sensitivity increases sixfold at low versus high latitudes. We conclude that conservation efforts to limit edges created by fragmentation will be most important in the worldâs tropical forests
BIOFRAG: A new database for analysing BIOdiversity responses to forest FRAGmentation
Habitat fragmentation studies are producing inconsistent and complex results across which it is nearly impossible to synthesise. Consistent analytical techniques can be applied to primary datasets, if stored in a flexible database that allows simple data retrieval for subsequent analyses. Method: We developed a relational database linking data collected in the field to taxonomic nomenclature, spatial and temporal plot attributes and further environmental variables (e.g. information on biogeographic region. Typical field assessments include measures of biological variables (e.g. presence, abundance, ground cover) of one species or a set of species linked to a set of plots in fragments of a forested landscape. Conclusion: The database currently holds records of 5792 unique species sampled in 52 landscapes in six of eight biogeographic regions: mammals 173, birds 1101, herpetofauna 284, insects 2317, other arthropods: 48, plants 1804, snails 65. Most species are found in one or two landscapes, but some are found in four. Using the huge amount of primary data on biodiversity response to fragmentation becomes increasingly important as anthropogenic pressures from high population growth and land demands are increasing. This database can be queried to extract data for subsequent analyses of the biological response to forest fragmentation with new metrics that can integrate across the components of fragmented landscapes. Meta-analyses of findings based on consistent methods and metrics will be able to generalise over studies allowing inter-comparisons for unified answers. The database can thus help researchers in providing findings for analyses of trade-offs between land use benefits and impacts on biodiversity and to track performance of management for biodiversity conservation in human-modified landscapes.Fil: Pfeifer, Marion. Imperial College London; Reino UnidoFil: Lefebvre, Veronique. Imperial College London; Reino UnidoFil: Gardner, Toby A.. Stockholm Environment Institute; SueciaFil: Arroyo RodrĂguez, VĂctor. Universidad Nacional AutĂłnoma de MĂ©xico; MĂ©xicoFil: Baeten, Lander. University of Ghent; BĂ©lgicaFil: Banks Leite, Cristina. Imperial College London; Reino UnidoFil: Barlow, Jos. Lancaster University; Reino UnidoFil: Betts, Matthew G.. State University of Oregon; Estados UnidosFil: Brunet, Joerg. Swedish University of Agricultural Sciences; SueciaFil: Cerezo BlandĂłn, Alexis Mauricio. Universidad de Buenos Aires. Facultad de AgronomĂa. Departamento de MĂ©todos Cuantitativos y Sistemas de InformaciĂłn; ArgentinaFil: Cisneros, Laura M.. University of Connecticut; Estados UnidosFil: Collard, Stuart. Nature Conservation Society of South Australia; AustraliaFil: DÂŽCruze, Neil. The World Society for the Protection of Animals; Reino UnidoFil: Da Silva Motta, Catarina. MinistĂ©rio da CiĂȘncia, Tecnologia, InovaçÔes. Instituto Nacional de Pesquisas da AmazĂŽnia; BrasilFil: Duguay, Stephanie. Carleton University; CanadĂĄFil: Eggermont, Hilde. University of Ghent; BĂ©lgicaFil: Eigenbrod, FĂ©lix. University of Southampton; Reino UnidoFil: Hadley, Adam S.. State University of Oregon; Estados UnidosFil: Hanson, Thor R.. No especifĂca;Fil: Hawes, Joseph E.. University of East Anglia; Reino UnidoFil: Heartsill Scalley, Tamara. United State Department of Agriculture. Forestry Service; Puerto RicoFil: Klingbeil, Brian T.. University of Connecticut; Estados UnidosFil: Kolb, Annette. Universitat Bremen; AlemaniaFil: Kormann, Urs. UniversitĂ€t Göttingen; AlemaniaFil: Kumar, Sunil. State University of Colorado - Fort Collins; Estados UnidosFil: Lachat, Thibault. Swiss Federal Institute for Forest; SuizaFil: Lakeman Fraser, Poppy. Imperial College London; Reino UnidoFil: Lantschner, MarĂa Victoria. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca; Argentina. Instituto Nacional de TecnologĂa Agropecuaria. Centro Regional Patagonia Norte. EstaciĂłn Experimental Agropecuaria San Carlos de Bariloche; ArgentinaFil: Laurance, William F.. James Cook University; AustraliaFil: Leal, Inara R.. Universidade Federal de Pernambuco; BrasilFil: Lens, Luc. University of Ghent; BĂ©lgicaFil: Marsh, Charles J.. University of Leeds; Reino UnidoFil: Medina Rangel, Guido F.. Universidad Nacional de Colombia; ColombiaFil: Melles, Stephanie. University of Toronto; CanadĂĄFil: Mezger, Dirk. Field Museum of Natural History; Estados UnidosFil: Oldekop, Johan A.. University of Sheffield; Reino UnidoFil: Overal , Williams L.. Museu Paraense EmĂlio Goeldi. Departamento de Entomologia; BrasilFil: Owen, Charlotte. Imperial College London; Reino UnidoFil: Peres, Carlos A.. University of East Anglia; Reino UnidoFil: Phalan, Ben. University of Southampton; Reino UnidoFil: Pidgeon, Anna Michle. University of Wisconsin; Estados UnidosFil: Pilia, Oriana. Imperial College London; Reino UnidoFil: Possingham, Hugh P.. Imperial College London; Reino Unido. The University Of Queensland; AustraliaFil: Possingham, Max L.. No especifĂca;Fil: Raheem, Dinarzarde C.. Royal Belgian Institute of Natural Sciences; BĂ©lgica. Natural History Museum; Reino UnidoFil: Ribeiro, Danilo B.. Universidade Federal do Mato Grosso do Sul; BrasilFil: Ribeiro Neto, Jose D.. Universidade Federal de Pernambuco; BrasilFil: Robinson, Douglas W.. State University of Oregon; Estados UnidosFil: Robinson, Richard. Manjimup Research Centre; AustraliaFil: Rytwinski, Trina. Carleton University; CanadĂĄFil: Scherber, Christoph. UniversitĂ€t Göttingen; AlemaniaFil: Slade, Eleanor M.. University of Oxford; Reino UnidoFil: Somarriba, Eduardo. Centro AgronĂłmico Tropical de InvestigaciĂłn y Enseñanza; Costa RicaFil: Stouffer, Philip C.. State University of Louisiana; Estados UnidosFil: Struebig, Matthew J.. University of Kent; Reino UnidoFil: Tylianakis, Jason M.. University College London; Estados Unidos. Imperial College London; Reino UnidoFil: Teja, Tscharntke. UniversitĂ€t Göttingen; AlemaniaFil: Tyre, Andrew J.. Universidad de Nebraska - Lincoln; Estados UnidosFil: Urbina Cardona, Jose N.. Pontificia Universidad Javeriana; ColombiaFil: Vasconcelos, Heraldo L.. Universidade Federal de Uberlandia; BrasilFil: Wearn, Oliver. Imperial College London; Reino Unido. The Zoological Society of London; Reino UnidoFil: Wells, Konstans. University of Adelaide; AustraliaFil: Willig, Michael R.. University of Connecticut; Estados UnidosFil: Wood, Eric. University of Wisconsin; Estados UnidosFil: Young, Richard P.. Durrell Wildlife Conservation Trust; Reino UnidoFil: Bradley, Andrew V.. Imperial College London; Reino UnidoFil: Ewers, Robert M.. Imperial College London; Reino Unid
Recommended from our members
BIOFRAG â a new database for analyzing BIOdiversity responses to forest FRAGmentation
Habitat fragmentation studies have produced complex results that are challenging
to synthesize. Inconsistencies among studies may result from variation in
the choice of landscape metrics and response variables, which is often compounded
by a lack of key statistical or methodological information. Collating
primary datasets on biodiversity responses to fragmentation in a consistent and
flexible database permits simple data retrieval for subsequent analyses. We present
a relational database that links such field data to taxonomic nomenclature,
spatial and temporal plot attributes, and environmental characteristics. Field
assessments include measurements of the response(s) (e.g., presence, abundance,
ground cover) of one or more species linked to plots in fragments
within a partially forested landscape. The database currently holds 9830 unique
species recorded in plots of 58 unique landscapes in six of eight realms: mammals
315, birds 1286, herptiles 460, insects 4521, spiders 204, other arthropods
85, gastropods 70, annelids 8, platyhelminthes 4, Onychophora 2, vascular
plants 2112, nonvascular plants and lichens 320, and fungi 449. Three landscapes
were sampled as long-term time series (>10 years). Seven hundred and
eleven species are found in two or more landscapes. Consolidating the substantial
amount of primary data available on biodiversity responses to fragmentation
in the context of land-use change and natural disturbances is an essential
part of understanding the effects of increasing anthropogenic pressures on land.
The consistent format of this database facilitates testing of generalizations concerning
biologic responses to fragmentation across diverse systems and taxa. It
also allows the re-examination of existing datasets with alternative landscape
metrics and robust statistical methods, for example, helping to address pseudo-replication
problems. The database can thus help researchers in producing
broad syntheses of the effects of land use. The database is dynamic and inclusive,
and contributions from individual and large-scale data-collection efforts
are welcome.Keywords: Species turnover,
Data sharing,
Database,
Global change,
Landscape metrics,
Edge effects,
Forest fragmentation,
Matrix contrast,
Bioinformatic
Data and code for: Natal legacies cause social and spatial marginalisation during dispersal
<p><strong>Abstract</strong></p>
<p><span>Early-life experiences can drive subsequent variation in social behaviours, but how differences among individuals emerge remains unknown. We combined experimental manipulations with GPS-tracking to investigate the pathways through which developmental conditions affect social network position during the early dispersal of wild red kites (<em>Milvus milvus</em>).<em> </em>Across 211 juveniles from 140 broods, last-hatched chicks—the least competitive—had the fewest number of peer encounters after fledging. However, when food supplemented, they had more encounters than all others. Using 4,425 bird-days of GPS data, we revealed that this was driven by differential responses to competition, with less competitive individuals naturally spreading out into marginal areas, and clustering in central foraging areas when food supplemented. Our results suggest that early-life adversities can cause significant natal legacies on individual behaviour beyond independence, with potentially far-reaching consequences on the social and spatial structure of animal populations.</span></p>
Data from: Primary rainforest amount at the landscape scale mitigates bird biodiversity loss and biotic homogenization
1.Tropical conservation strategies traditionally focus on large tracts of pristine forests, but given rapid primary forest decline, understanding the role of secondary forest remnants for biodiversity maintenance is critical. Until now, the interactive effects of changes in forest amount, configuration and disturbance history (secondary vs. primary forest) on the conservation value of tropical landscapes has remained unknown, hampering the incorporation of these global change drivers into local and global conservation planning.
2.We disentangled effects of landscape wide forest amount, fragment size, and forest age (old growth versus secondary forest) on abundance, α-diversity, ÎČ-diversity (biotic homogenisation) and community shifts of bird communities in human-dominated landscapes of southern Costa Rica. Utilizing two complementary methods, yielding 6900 individual detections and 223 species, we characterized bird communities in 49 forest fragments representing independent gradients in fragment size (30 ha) and forest amount (5%-80%) in the surrounding landscape (within 1000 m).
3.Abundance and α-diversity of forest specialists and insectivores declined by half in small fragments, but only in landscapes with little old growth forest. Conversely, secondary forest at the landscape scale showed no such compensation effect. Similarly, a null-model approach indicated significant biotic homogenisation in small versus large fragments, but only in landscapes with little old growth forest, suggesting forest amount and configuration interactively affect ÎČ-diversity in tropical human-dominated landscapes. Finally, dramatic abundance-based community shifts relative to intact forests are largely a result of landscape-scale loss of old growth rather than changes in overall forest cover.
4.Policy implications. Our study provides strong evidence that retaining old growth within tropical human modified landscapes can simultaneously curb erosion of avian forest specialist α-diversity, mitigate collapse of ÎČ-diversity (biotic homogenisation) and dampen detrimental avian community shifts. However, secondary forests play, at best, a subordinate role to mitigate these processes. To maintain tropical forest biodiversity, retaining old growth forest within landscapes should be first priority, highlighting a land-sparing approach
Elevated inbreeding in Heliconia tortuosa is determined by tropical forest stand age, isolation and loss of hummingbird functional diversity
Forest conversion and habitat loss are major threats to biological diversity. Forest regeneration can mitigate the negative effects of old-growth forest loss on species diversity, but less is known about the extent to which forest loss reduces genetic diversity in remnant populations and whether secondary forests play a role in the maintenance of genetic diversity. We quantified genetic diversity in a tropical hummingbird-pollinated understorey herb, Heliconia tortuosa, across a landscape mosaic of primary and secondary forest regrowth. Using microsatellite genotypes from \u3e850 adult and juvenile plants within 33 forest patches and extensive bird surveys, we examined the effect of contemporary and historical landscape features including forest age (primary vs. secondary forest), stand isolation and pollinator assemblages on genetic diversity and levels of inbreeding in H. tortuosa. We found that inbreeding was up to three times higher in secondary forest, and this effect was amplified with reductions in primary forest in the surrounding landscape through reduced observed heterozygosity in isolated fragments. Inbreeding in forest patches was negatively correlated with the local frequency of specialist long-distance foraging traplining hummingbirds. Traplining hummingbirds therefore appear to facilitate mating among unrelated plantsâan inference we tested using empirically parameterized simulations. Higher levels of inbreeding in H. tortuosa are therefore associated with reduced functional diversity of hummingbirds in secondary forests and forest patches isolated from primary forests. Our findings suggest a cryptic consequence of primary forest loss and secondary forest regeneration through the disruption of mutualistic interactions resulting in the erosion of genetic diversity in a common understorey plant