Steffen U. Pauls

Phylogeography of the montane caddisfly Drusus discolor: evidence for multiple refugia and periglacial survival.

We studied the genetic population structure and phylogeography of the montane caddisfly Drusus discolor across its entire range in central and southern Europe. The species is restricted to mountain regions and exhibits an insular distribution across the major mountain ranges. Mitochondrial sequence data (COI) of 254 individuals from the entire species range is analysed to reveal population genetic structure. The data show little molecular variation within populations and regions, but distinct genetic differentiation between mountain ranges. Most populations are significantly differentiated based on FST and exact tests of population differentiation and most haplotypes are unique to a single mountain range. Phylogenetic analyses reveal deep divergence between geographically isolated lineages. Combined, these results suggest that past fragmentation is the prominent process structuring the populations across Europe. We use tests of selective neutrality and mismatch distributions, to study the demographic population history of regions with haplotype overlap. The high level of genetic differentiation between mountain ranges and estimates of demographic history provide evidence for the existence of multiple glacial refugia, including several in central Europe. The study shows that these aquatic organisms reacted differently to Pleistocene cooling than many terrestrial species. They persisted in numerous refugia over multiple glacial cycles, allowing many local endemic clades to form.

The role of the uplift of the Qinghai-Tibetan Plateau for the evolution of Tibetan biotas

Biodiversity is unevenly distributed on Earth and hotspots of biodiversity are often associated with areas that have undergone orogenic activity during recent geological history (i.e. tens of millions of years). Understanding the underlying processes that have driven the accumulation of species in some areas and not in others may help guide prioritization in conservation and may facilitate forecasts on ecosystem services under future climate conditions. Consequently, the study of the origin and evolution of biodiversity in mountain systems has motivated growing scientific interest. Despite an increasing number of studies, the origin and evolution of diversity hotspots associated with the Qinghai‐Tibetan Plateau (QTP) remains poorly understood. We review literature related to the diversification of organisms linked to the uplift of the QTP. To promote hypothesis‐based research, we provide a geological and palaeoclimatic scenario for the region of the QTP and argue that further studies would benefit from providing a complete set of complementary analyses (molecular dating, biogeographic, and diversification rates analyses) to test for a link between organismic diversification and past geological and climatic changes in this region. In general, we found that the contribution of biological interchange between the QTP and other hotspots of biodiversity has not been sufficiently studied to date. Finally, we suggest that the biological consequences of the uplift of the QTP would be best understood using a meta‐analysis approach, encompassing studies on a variety of organisms (plants and animals) from diverse habitats (forests, meadows, rivers), and thermal belts (montane, subalpine, alpine, nival). Since the species diversity in the QTP region is better documented for some organismic groups than for others, we suggest that baseline taxonomic work should be promoted.

Assessing streams in Germany with benthic invertebrates: development of a practical standardised protocol for macroinvertebrate sampling and sorting

Abstract In the past, no single standardised method for sampling and sorting benthic macroinvertebrates has been implemented in Germany. Therefore, we tested the suitability of two common sorting protocols, RIVPACS and AQEM/STAR, by taking samples with each protocol at 44 sampling sites. Our results reveal that different methods deliver slightly different assessment results. Moreover these two methods differ in costs. Although the AQEM/STAR protocol takes longer than the RIVPACS protocol, we favoured the AQEM/STAR protocol because of its higher level of standardisation. In order to limit costs to an acceptable level, a modification of the AQEM/STAR protocol (MAS method) is developed. This method is highly standardised, gives stable assessment results and is relatively inexpensive (€ 224.00 for processing of an average sample). A detailed protocol of the newly developed method is given.

Population genetics of ecological communities with DNA barcodes: An example from New Guinea Lepidoptera

Comparative population genetics of ecological guilds can reveal generalities in patterns of differentiation bearing on hypotheses regarding the origin and maintenance of community diversity. Contradictory estimates of host specificity and beta diversity in tropical Lepidoptera (moths and butterflies) from New Guinea and the Americas have sparked debate on the role of host-associated divergence and geographic isolation in explaining latitudinal diversity gradients. We sampled haplotypes of mitochondrial cytochrome c oxidase I from 28 Lepidoptera species and 1,359 individuals across four host plant genera and eight sites in New Guinea to estimate population divergence in relation to host specificity and geography. Analyses of molecular variance and haplotype networks indicate varying patterns of genetic structure among ecologically similar sympatric species. One-quarter lacked evidence of isolation by distance or host-associated differentiation, whereas 21% exhibited both. Fourteen percent of the species exhibited host-associated differentiation without geographic isolation, 18% showed the opposite, and 21% were equivocal, insofar as analyses of molecular variance and haplotype networks yielded incongruent patterns. Variation in dietary breadth among community members suggests that speciation by specialization is an important, but not universal, mechanism for diversification of tropical Lepidoptera. Geographically widespread haplotypes challenge predictions of vicariance biogeography. Dispersal is important, and Lepidoptera communities appear to be highly dynamic according to the various phylogeographic histories of component species. Population genetic comparisons among herbivores of major tropical and temperate regions are needed to test predictions of ecological theory and evaluate global patterns of biodiversity.

Patterns of population structure in two closely related, partially sympatric caddisflies in Eastern Europe: historic introgression, limited dispersal, and cryptic diversity1

Abstract We used 2 caddisflies, Drusus discolor and Drusus romanicus, to test explicitly whether closely related species that occupy similar niches and occur in partial sympatry maintain comparable population structure and share a similar population history. We used mitochondrial sequence data to analyze and compare the population structure and the phylogeography of 105 specimens of D. discolor and 74 individuals of D. romanicus collected in southeastern Europe. We examined the relationship between both species with phylogenetic inference and coalescent modeling and used the results to assign larvae to species. We were able to unambiguously assign larvae to species level based on clearly defined association criteria within a phylogenetic analysis of all specimens. The species were closely related and not reciprocally monophyletic in our haplotype phylogeny. One D. romanicus haplotype from the Bucegi Mountains was nested within D. discolor, a result that suggests isolation with migration, introgression, or incomplete lineage sorting between the 2 species. For each species, we examined population genetic structure with median joining networks, analysis of molecular variance (AMOVA), exact tests of population differentiation, and Mantel tests of isolation by distance. We used tests for selective neutrality (Tajimas D, Fus F) to infer potential population growth and expansion. Species differed in their genetic population structure. Drusus discolor had haplotype overlap among several mountain ranges in the study region. No D. romanicus haplotypes were shared among any regions examined, and levels of divergence between haplotype clades exceeded those of D. discolor by a factor of up to 2.1. The different degree of population differentiation and divergence of both species probably reflects different Pliocene/Pleistocene population histories and might be related to differences in dispersal capabilities or competitive exclusion of D. romanicus by D. discolor in the mountain ranges north and west of the Western Carpathians. Based on our results, we discuss the importance of the Carpathian Mountains and Bulgarian highlands as Pliocene/Pleistocene refugia and centers of diversification.

Freshwater Biodiversity and Aquatic Insect Diversification

Inland waters cover less than 1% of Earths surface but harbor more than 6% of all insect species: Nearly 100,000 species from 12 orders spend one or more life stages in freshwater. Little is known about how this remarkable diversity arose, although allopatric speciation and ecological adaptation are thought to be primary mechanisms. Freshwater habitats are highly susceptible to environmental change and exhibit marked ecological gradients. Standing waters appear to harbor more dispersive species than running waters, but there is little understanding of how this fundamental ecological difference has affected diversification. In contrast to the lack of evolutionary studies, the ecology and habitat preferences of aquatic insects have been intensively studied, in part because of their widespread use as bioindicators. The combination of phylogenetics with the extensive ecological data provides a promising avenue for future research, making aquatic insects highly suitable models for the study of ecological diversification.

Grazers, shredders and filtering carnivores-The evolution of feeding ecology in Drusinae (Trichoptera: Limnephilidae) : Insights from a molecular phylogeny

We examined the phylogenetic relationships between species and genera within the caddisfly subfamily Drusinae (Trichoptera: Limnephilidae) using sequence data from two mitochondrial loci (cytochrome oxidase 1, large subunit rRNA) and one nuclear gene (wingless). Sequence data were analysed for 28 species from five genera from the subfamily. We analysed individual and combined data sets using a Bayesian Markov Chain Monte Carlo and a maximum parsimony approach and compared the performance of each partition for resolving phylogenetic relationships at this level. In terms of resolution and phylogenetic utility wingless outperformed the two mitochondrial gene partitions. Using both Shimodaira-Hasegawa and expected likelihood weights tests we tested several hypotheses of relationships previously inferred based on adult morphological characters. The data did not support the generic concept, or many previously proposed species groupings, based on adult morphology. In contrast, the molecular data correlated with the morphology and feeding ecology of larvae. Using Bayesian ancestral character state reconstructions we inferred the evolution of feeding ecology and relevant larval morphological characters. Our analyses showed that within the subfamily Drusinae two derived feeding types evolved. One of these--grazing epilithic algae--is otherwise unusual in the Limnephilidae and may have promoted the high degree of diversity in the Drusinae.

DNA barcode data confirm new species and reveal cryptic diversity in Chilean Smicridea (Smicridea) (Trichoptera:Hydropsychidae)

Abstract Mitochondrial deoxyribonucleic acid (mtDNA) sequence data have been both heralded and scrutinized for their ability or lack thereof to discriminate among species for identification (DNA barcoding) or description (DNA taxonomy). Few studies have systematically examined the ability of mtDNA from the DNA barcode region (658 base pair fragment of the 5′ terminus of the mitochondrial cytochrome c oxidase I gene) to distinguish species based on range-wide sampling of specimens from closely related species. Here we examined the utility of DNA barcode data for delimiting species, associating life stages, and as a potential genetic marker for phylogeographic studies by analyzing a range-wide sample of closely related Chilean representatives of the caddisfly genus Smicridea subgenus Smicridea. Our data revealed the existence of 7 deeply diverged, previously unrecognized lineages and confirmed the existence of 2 new species: Smicridea (S.) patinae, new species and Smicridea (S.) lourditae, new species. Based on our current taxonomic evaluation, we considered the other 5 lineages to be cryptic species. The DNA barcode data proved useful in delimiting species within Chilean Smicridea (Smicridea) and were suitable for life-stage associations. The data also contained sufficient intraspecific variation to make the DNA barcode a candidate locus for widespread application in phylogeographic studies.

Assessing the impact of errors in sorting and identifying macroinvertebrate samples

This study assesses the impact of errors in sorting and identifying macroinvertebrate samples collected and analysed using different protocols (e.g. STAR-AQEM, RIVPACS). The study is based on the auditing scheme implemented in the EU-funded project STAR and presents the first attempt at analysing the audit data. Data from 10 participating countries are analysed with regard to the impact of sorting and identification errors. These differences are measured in the form of gains and losses at each level of audit for 120 samples. Based on gains and losses to the primary results, qualitative binary taxa lists were deducted for each level of audit for a subset of 72 data sets. Between these taxa lists the taxonomic similarity and the impact of differences on selected metrics common to stream assessment were analysed. The results of our study indicate that in all methods used, a considerable amount of sorting and identification error could be detected. This total impact is reflected in most functional metrics. In some metrics indicative of taxonomic richness, the total impact of differences is not directly reflected in differences in metric scores. The results stress the importance of implementing quality control mechanisms in macroinvertebrate assessment schemes.

First audit of macroinvertebrate samples from an EU Water Framework Directive monitoring program: human error greatly lowers precision of assessment results

Abstract Invertebrates are often used in biological monitoring of soil and water ecosystems. Because of the huge number of invertebrate species, sample processing (sorting and identification) is a labor-intensive and often difficult task that is prone to error. These errors can bias assessment results, which often are used by environmental managers to guide funding decisions for costly restoration measures. However, quality control of assessment results is not implemented in many freshwater monitoring programs. We conducted the first audit of an official European freshwater monitoring program based on 414 macroinvertebrate samples from streams and rivers in Germany. The samples were collected by personnel at 7 different commercial environmental laboratories using the European Union (EU) Water Framework Directive protocol. We audited 12% of all samples at 3 different levels: 1) a sorting audit, 2) an identification audit, and 3) a total audit based on both sorting and identification. The sorting audit revealed that 29% of the specimens and every 5th taxon (20.6%) had been overlooked by the primary analyst. Differences in sorting were correlated with taxon body size (r  =  0.61, p < 0.001). The identification audit showed that >30% of taxa differed between the results of the primary analysts and auditors. Taxa considered difficult to identify were not more prone to error than were taxa considered easier to identify. Primary analysts and auditors assigned 34% of audited samples to different quality classes in ≥1 of 3 assessment modules (organic pollution, acidification, and general degradation). For 16% of the samples, these changes resulted in a different final ecological assessment. Such a high rate of differences between primary analysts and auditors could lead to ineffective allocation of several million Euros. Our results clearly illustrate the need for adequate quality control and auditing in freshwater monitoring.