Biology subjects

Flojgaard, C.

Publications and source records attributed to Flojgaard, C..

8 recordsLinked to original sources

bioRxiv2020

Detecting flying insects using mega-nets and meta-barcoding

Insect diversity and abundance are increasingly reported as being under pressure. However, monitoring insects across space and time is challenging, due to their vast taxonomic and functional diversity. This study demonstrates how nets mounted on rooftops of cars (car nets) and DNA metabarcoding can be applied to sample flying insect diversity across a large spatial scale within a limited time period. During June 2018, 365 car net samples were collected by 151 volunteers during two daily time intervals on 218 routes in Denmark. Insect bulk samples were processed with a DNA metabarcoding protocol to estimate taxonomic composition, and the results were compared to known flying insect diversity and occurrence data. We detected 15 out of 19 flying insect orders present in Denmark. Diptera. Psocoptera and Thysanoptera were overrepresented, while Hymenoptera, Coleoptera, Lepidoptera, Trichoptera, Odonata, Neuroptera and Plecoptera were underrepresented, compared to Danish estimates. We detected 319 species not known for Denmark. Our results indicate that this method can assess the flying insect fauna to a wide extent, but may be, like other methods, biased towards certain insect orders. Furthermore, car net sampling and DNA metabarcoding can update species records for Denmark while preserving specimens for natural history collections.

ecology↗

bioRxiv2020

Contrasting impacts of urban and farmland cover on flying insect biomass

Recent studies report declines in biomass, abundance and diversity of terrestrial insect groups. While anthropogenic land use is one likely contributor to this decline, studies assessing land cover as a driver of insect dynamics are rare and mostly restricted in spatial scale and types of land cover. In this study, we used rooftop-mounted car nets in a citizen science project ( InsectMobile) to allow for large-scale geographic sampling of flying insects across Denmark and parts of Germany. Citizen scientists sampled insects along 278 10 km routes in urban, farmland and semi-natural (grassland, wetland and forest) landscapes in the summer of 2018. We assessed the importance of local to landscape-scale effects and land use intensity by relating insect biomass to land cover in buffers of 50, 250, 500 and 1000 m along the routes. We found a negative association of urban cover and a positive association of farmland on insect biomass at a landscape-scale (1000 m buffer) in both countries. In Denmark, we also found positive effects of all semi-natural land covers, i.e. grassland (largest at the landscape-scale, 1000 m), forests (largest at intermediate scales, 250 m), and wetlands (largest at the local-scale, 50 m). The negative association of insect biomass with urban land cover and positive association with farmland were not clearly modified by any variable associated with land use intensity. Our results show that land cover has an impact on flying insect biomass with the magnitude of this effect varying across spatial scales. Since we consistently found negative effects of urban land cover, our findings highlight the need for the conservation of semi-natural areas, such as wetlands, grasslands and forests, in Europe.

ecology↗

bioRxiv2020

Investigating the drivers of macro-fungal dark diversity using LiDAR

Despite the important role of fungi for ecosystems, relatively little is known about the factors underlying the dynamics of their diversity. Moreover, studies do not typically consider their dark diversity: the species absent from an otherwise suitable site. Here, we examined potential drivers of local fungal dark diversity in temperate woodland and open habitats using LiDAR and in-situ field measurements, combined with a systematically collected and geographically comprehensive macro-fungi and plant data set. For the first time, we also estimated species pools of fungi by considering both plant and fungi co-occurrences. The most important LiDAR variables for modelling fungal dark diversity were amplitude and echo ratio, which are both thought to represent vegetation structure. These results suggest that the local fungal dark diversity is highest in production forests like plantations and lowest in more open forests and in open habitats with little woody vegetation. Plant species richness was the strongest explanatory factor overall and negatively correlated with local fungal dark diversity. Soil fertility showed a positive relationship with dark diversity in open habitats. These findings may indicate that the local dark diversity of macro-fungi is highest in areas with a relatively high human impact (typically areas with low plant species richness and high soil fertility). Overall, this study brings novel insights into local macro-fungi dark diversity patterns, suggesting that a multitude of drivers related to both soil and vegetation act in concert to determine fungal dark diversity.

ecology↗

bioRxiv2020

Simple attributes predict the importance of plants as hosts to the richness of fungi and arthropods

Consumers constitute the vast majority of global terrestrial biodiversity. Yet, local consumer richness is poorly understood. Plant species richness offers a simple hypothesis to how the diversification of carbon substrates may promote the diversity of arthropods and fungi. We took this one step further and used databases on plant-consumer interaction links to derive the richness of associated biota per plant species (link score). Using a species inventory of 130 sites we investigated 1) how well the link score could be predicted by plant attributes and 2) if the sum of plant species observed or predicted link scores could predict site richness of arthropods and macrofungi better than plant species richness alone. We found plant link scores to be positively related to plant size, abundance, nativeness and ectomycorrhizal status. Link based indices generally improved prediction of richness, stressing the importance of plants as niche space for the megadiverse groups of insects and fungi.

ecology↗

bioRxiv2019

Multi-taxon inventory reveals highly consistent biodiversity responses to ecospace variation

Amidst the global biodiversity crisis, identifying drivers of biodiversity variation remains a key challenge. Scientific consensus is limited to a few macroecological rules, such as species richness increasing with area, which provide limited guidance for conservation. In fact, few agreed ecological principles apply at the scale of sites or reserve management, partly because most community-level studies are restricted to single habitat types and species groups. We used the recently proposed ecospace framework and a comprehensive data set for aggregating environmental variation to predict multi-taxon diversity. We studied richness of plants, fungi, and arthropods in 130 sites representing the major terrestrial habitat types in Denmark. We found the abiotic environment (ecospace position) to be pivotal for the richness of primary producers (vascular plants, mosses, and lichens) and, more surprisingly, little support for ecospace continuity as a driver. A peak in richness at intermediate productivity adds new empirical evidence to a long-standing debate over biodiversity responses to productivity. Finally, we discovered a dominant and positive response of fungi and insect richness to organic matter accumulation and diversification (ecospace expansion). Two simple models of producer and consumer richness accounted for 77 % of the variation in multi-taxon species richness suggesting a significant potential for generalization beyond individual species responses. Our study widens the traditional conservation focus on vegetation and vertebrate populations unravelling the importance of diversification of carbon resources for diverse heterotrophs, such as fungi and insects.

ecology↗

bioRxiv2019

Dark diversity reveals importance of biotic resources and competition for plant diversity across broad environmental gradients

Species richness is the most commonly used metric to quantify biodiversity. However, examining dark diversity, the group of missing species which can potentially inhabit a site, can provide a more thorough understanding of the processes influencing observed biodiversity and help evaluate the restoration potential of local habitats. So far, dark diversity has mainly been studied for specific habitats or largescale landscapes while less attention has been given to variation across broad environmental gradients or as a result of local conditions and biotic interactions. In this study, we investigate the importance of local environmental conditions in determining dark diversity and observed richness in plant communities across broad environmental gradients. We use the ecospace concept to investigate how abiotic gradients (defined as position), availability of biotic resources (defined as expansion), spatiotemporal extent of habitats (defined as continuity), as well as species interactions through competition, relate to these biodiversity measures. Position variables were important for both plant richness and dark diversity, some with quadratic relationships, e.g., plant richness showing a unimodal response to soil fertility corresponding to the intermediate productivity hypothesis. Competition represented by community mean Grime C showed a negative correlation with plant richness. Besides position, organic carbon was the most important variable for dark diversity, indicating that in late succession habitats such as forests and shrubs, dark diversity is generally low. The importance of Grime C indicate that intermediate disturbance, such as grazing, may facilitate higher species richness and lower dark diversity. Comparing various biodiversity metrics and their influencing factors might reveal important drivers of biodiversity changes and result in better conservation decision-making.

ecology↗

bioRxiv2018

Predicting provenance of forensic soil samples: soil DNA predicts habitat and environmental properties

Environmental DNA is increasingly applied in ecological studies, including forensic ecology where eDNA from soil can be used to pair samples or reveal sample provenance. We collected soil eDNA samples as part of a large national biodiversity research project across 130 sites in Denmark. We investigated the potential for soil eDNA in predicting provenance in terms of environmental conditions, habitat characteristics and geographic regions. We used linear regression for predicting environmental gradients of light, moisture, soil pH and nutrients (represented by Ellenberg Indicator Values, EIVs) and quadratic discriminant analysis (QDA) to predict habitat class and geographic region. We found high predictive power for environmental gradients (R2 > 0.73). The discriminatory power of QDA in predicting habitat characteristics varied from high accuracy in predicting certain forest types, less accurate prediction of heathland and poor accuracy for geographic region. We demonstrate the application of provenance prediction in forensic science by evaluating and discussing two mock crime scenes. Here, we supplement with plant species lists from annotated sequences. Where predictions of environmental gradients and habitat classes give an overall accurate description of a crime scene, care should be taken when interpreting annotated sequences, e.g. due to erroneous assignments in GenBank. The outlined approach clearly demonstrates that basic ecological information that can be extracted from soil eDNA, contributing to the range of potential applications of eDNA in forensic ecology.

ecology↗

bioRxiv2018

Vascular plants are strong predictors of multi-taxon species richness

Plants regulate soils and microclimate, provide substrate for heterotrophic taxa, are easy to observe and identify and have a stable taxonomy, which strongly justifies the use of plants as bioindicators in monitoring and conservation. However, insects and fungi make up the vast majority of species. Surprisingly, it remains untested whether plants are strong predictors of total multi-taxon species richness. To answer this question, we collected an extensive data set on species richness of vascular plants, bryophytes, macrofungi, lichens, plant-galling arthropods, gastropods, spiders, carabid beetles, hoverflies and OTU richness from environmental DNA metabarcoding. Plant species richness per se was a moderate predictor of richness of other taxa. Taking an ecospace approach to modelling, the addition of plant-derived bioindicators revealed 1) a consistently positive effect of plant richness on other taxa, 2) prediction of 12-55% of variation in other taxa and 48 % of variation in the total species richness.

ecology↗