Julia Tiede | University of Münster (original) (raw)

Papers by Julia Tiede

Landscape Ecology, Jun 3, 2022

Ecosphere, Apr 1, 2017

The diversity and community composition of ground arthropods is routinely analyzed by pitfall tra... more The diversity and community composition of ground arthropods is routinely analyzed by pitfall trap sampling, which is a cost-and time-effective method to gather large numbers of replicates but also known to generate data that are biased by species-specific differences in locomotory activity. Previous studies have looked at factors that influence the sampling bias. These studies, however, were limited to one or few species and did rarely quantify how the species-specific sampling bias shapes communitylevel diversity metrics. In this study, we systematically quantify the species-specific and community-level sampling bias with an allometric individual-based model that simulates movement and pitfall sampling of 10 generic ground arthropod species differing in body mass. We perform multiple simulation experiments covering different scenarios of pitfall trap number, spatial trap arrangement, temperature, and population density. We show that the sampling bias decreased strongly with increasing body mass, temperature, and pitfall trap number, while population density had no effect and trap arrangement only had little effect. The average movement speed of a species in the field integrates body mass and temperature effects and could be used to derive reliable estimates of absolute species abundance. We demonstrate how unbiased relative species abundance can be derived using correction factors that need only information on species body mass. We find that community-level diversity metrics are sensitive to the particular community structure, namely the relation between body mass and relative abundance across species. Generally, pitfall trap sampling flattens the rank-abundance distribution and leads to overestimations of ground arthropod Shannon diversity. We conclude that the correction of the species-specific pitfall trap sampling bias is necessary for the reliability of conclusions drawn from ground arthropod field studies. We propose bias correction is a manageable task using either body mass to derive unbiased relative abundance or the average speed to derive reliable estimates of absolute abundance from pitfall trap sampling.

Ecology and Evolution, Sep 12, 2017

This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Research Square (Research Square), Jan 3, 2022

20 We would like to thank the landowners who allowed us to sample lady beetles on their land, and... more 20 We would like to thank the landowners who allowed us to sample lady beetles on their land, and we also 21 thank Rachel Mallinger, Hannah Gaines-Day, Heidi Liere, Allison Dehnel, and Ken Frost for rides to the sampling sites. This research was supported by the United States Department of Agriculture (USDA) grants 23

Organisms detected with NGS in regurgitates of P. melanarius... more Organisms detected with NGS in regurgitates of P. melanarius, sorted by their most likely type of interaction with the beetle.</p

Points represent individual plots and are scaled based on the logarithm of the number of... more Points represent individual plots and are scaled based on the logarithm of the number of sequences, blue lines show GLM predictions, blue polygons show 95% confidence intervals for effects with p<0.05, red lines and red polygons refer to GLMs weighted by the number of sequences. A) Total number of feeding interactions including prey and plant taxa, B) feeding interactions involving plant taxa, C) feeding interactions involving total prey taxa, D) feeding interactions involving intraguild predation, and E) neutral interactions.</p

The six panels show the three kingdoms (Plantae, Animalia, and Fungi). Points represent ... more The six panels show the three kingdoms (Plantae, Animalia, and Fungi). Points represent OTUs, aggregated at family level, that were detected in at least two levels of plant species richness. Lines (smoother span = 1.6) show least-squares fits for illustrative purposes only.</p

Summary of generalized linear model results on the effect of plant species richness, pla... more Summary of generalized linear model results on the effect of plant species richness, plant functional diversity and percent vegetation cover on the number of OTUs detected in each interaction group.</p

(A) Overview of plots of the Trait-Based Experiment with enclosures. (B) Enclosures were... more (A) Overview of plots of the Trait-Based Experiment with enclosures. (B) Enclosures were made of construction foil sunk into the soil using PVC panels. (C) Marked beetles were released and recaptured to sample regurgitates (D) sampling regurgitates. Photographs by J. Tiede.</p

(A) Predatory mite (Trombidiformes: Trombiculidae) in a plot of the Jena-Experiment. (B)... more (A) Predatory mite (Trombidiformes: Trombiculidae) in a plot of the Jena-Experiment. (B) Mite isolated from a gut of P. melanarius (C). Phoretic mites (Mesostigmata: Parasitidae) on P. melanarius. Photographs by C. Scherber.</p

Basic and Applied Ecology, Nov 1, 2021

Background/Question/Methods Coccinellid beetles are known as important predators of crop pests in... more Background/Question/Methods Coccinellid beetles are known as important predators of crop pests in agro-ecosystems. As generalists, they feed on a number of different prey species and can switch to plant derived resources in times when prey is scare. Past research has shown that the abundance and diversity of coccinellid species in crop habitats IS influenced by the composition of the surrounding landscape. However, landscape structure may also be important determinants of fitness-related traits of coccinellids, via spatial and temporal variation in quality and quantity of food supply. To investigate the effects of landscape diversity and composition on the physiological condition of coccinellids we sampled adult beetles of common species across a gradient of agricultural intensification in locations around Madison, Wisconsin from May till September 2011. The measured indicators of body condition included the relative content of body fat and an index for body size. Both are thought t...

Landscape Ecology

Context Agricultural intensification is contributing to a global species decline. Underlying mech... more Context Agricultural intensification is contributing to a global species decline. Underlying mechanisms include toxic effects of pesticides on non-target organisms and reductions in habitat and food availability. However, the effects of agricultural intensification on body condition, particularly of ecosystem service-providing arthropods, are poorly understood. Objectives Here, we investigated whether variations in the body condition of common lady beetle species (Coleoptera: Coccinellidae) can be explained by the composition and configuration of the surrounding landscape. Assuming strong seasonal variation in food availability in intensively farmed regions, we included the entire period of lady beetle activity in our study. Methods Lady beetles were collected from April to September 2011 in 30 landscapes in southern Wisconsin, USA. We examined how body size, body density, and lipid content of the beetles responded to the percentage of intensive cropland, habitat diversity, and edge...

Lady beetles (Coccinellidae) are polyphagus omnivores that employ a non-selective feeding strateg... more Lady beetles (Coccinellidae) are polyphagus omnivores that employ a non-selective feeding strategy to optimize their energy and nutrient intake. Thus, the ability of coccinellids to realize a mixed diet might depend on the resource diversity within a habitat. To investigate how the habitat type affects the diet of coccinellids we analyzed their gut bacterial community. The majority of bacteria recovered from insect guts are likely transient organisms ingested with food. As a consequence, the gut bacterial diversity of coccinellidae may serve as an indicator of their diet diversity, and by extension, of resource availability within a local habitat. We hypothesize that high food diversity will be reflected by a higher richness of gut bacteria in coccinellids. Specimens of four coccinellid species were collected during July 2012 in eight soy bean fields and eight prairies in southern Wisconsin. These habitat types represent a contrasting diversity of plants and associated prey for cocc...