North Temperate Regions Research Articles

Can biogeography help bumblebee conservation?

Bumblebees (Bombus Latreille, 1802), because of their large body size, bright colours and activity at times and places that coincide with biologists, are an example of a group of insects that is particularly well represented in museum collections. This is important if taxonomic revisions are to achieve greater comparability among species. Bumblebees have also attracted particular attention because they are especially ecologically and economically valuable for pollination in north temperate regions, where they are now becoming increasingly threatened. I argue that the what, the where, and the how of effective conservation management may be informed by understanding the divergent characteristics that have affected their biogeographical past: by helping us to see ‘the woods’, not just ‘the trees’, of their habitat needs. Identifying suitable habitat should be part of reconstructing historical biogeography within taxonomic revisions. For bumblebees, for example, biogeographical analysis associates major taxonomic groups either with flower-rich lowland grasslands or with flower-rich montane grasslands, highlighting their contrasting requirements for: nest sites, flowers of different depths, pollen-plant families, and especially the differing importance of early spring and late summer flowers for breeding success. This broad view of species groups helps filter the less important idiosyncrasies from local case studies in order to focus conservation actions.

Climate-influenced boreotropical survival and rampant introgressionsexplain the thriving of New World grapes in the north temperate zone.

The north temperate region was characterized by a warm climate and a rich thermophilic flora before the Eocene, but early diversifications of the temperate biome under global climate change and biome shift remain uncertain. Moreover, it is becoming clear that hybridization/introgression is an important driving force of speciation in plant diversity. Here, we applied analyses from biogeography and phylogenetic networks to account for both introgression and incomplete lineage sorting based on genomic data from the New World Vitis, a charismatic component of the temperate North American flora with known and suspected gene flow among species. Biogeographic inference and fossil evidence suggest that the grapes were widely distributed from North America to Europe during the Paleocene to the Eocene, followed by widespread extinction and survival of relicts in the tropical New World. During the climate warming in the early Miocene, a Vitis ancestor migrated northward from the refugia with subsequent diversification in the North American region. We found strong evidence for widespread incongruence and reticulate evolution among nuclear genes within both recent and ancient lineages of the New World Vitis. Furthermore, the organellar genomes showed strong conflicts with the inferred species tree from the nuclear genomes. Our phylogenomic analyses provided an important assessment of the wide occurrence of reticulate introgression in the New World Vitis, which potentially represents one of the most important mechanisms for the diversification of Vitis species in temperate North America and even the entire temperate Northern Hemisphere. The scenario we report here may be a common model of temperate diversification of flowering plants adapted to the global climate cooling and fluctuation in the Neogene.

Effects of Plasticity on Elevational Range Size and Species Richness.

AbstractElevational ranges within many taxa are greater in the north temperate region than the tropics. Two hypotheses to explain the pattern are, first, that large elevational ranges in the temperate region arise because species have evolved broad tolerance curves in response to seasonality and, second, that a low diversification rate in the temperate region (speciation minus extinction) has led to relatively few species, each of which occupies a large elevational range in the absence of competitors (character release). We build a quantitative genetic model of selection on a phenotypic trait, whereby increased tolerance is modeled as arising from plasticity in the trait. We show that broad tolerances result in evolution of large elevational ranges because they induce shallower genotypic clines and hence reduced maladaptive gene flow. The evolution of large elevational ranges results in relatively few competing species arranged along the elevational gradient at a species carrying capacity. In such saturated communities, species have much elevational overlap. In contrast, in similar-sized communities that could accommodate many more species, the resulting character release is associated with smaller elevational overlaps. Empirical assessment of these predictions should contribute to assessing any role for ecological limits in driving the latitudinal diversity gradient in species richness.

Can correlational analyses help determine the drivers of microcystin occurrence in freshwater ecosystems? A meta-analysis of microcystin and associated water quality parameters.

Microcystin (MC) is a toxic secondary metabolite produced by select cyanobacteria that threatens aquatic and terrestrial organisms over a diverse range of freshwater systems. To assess the relationship between environmental parameters and MC, researchers frequently utilize correlational analyses. This statistical methodology has proved useful when summarizing complex water quality monitoring datasets, but the correlations between select parameters and MC have been documented to vary widely across studies and systems. Such variation within the peer-reviewed literature leaves uncertainty for resource managers when developing a MC monitoring program. The objective of this research is to determine if correlational analyses between environmental parameters and MC are helpful to resource managers desiring to understand the drivers of MC. Environmental (i.e., physical, chemical, and biological) and MC correlation data were retrieved from an estimated 2,643 waterbodies (largely from the north temperate region) and synthesized using a Fisher's z meta-analysis. Common water quality parameters, such as chlorophyll, temperature, and pH, were positively correlated with MC, while transparency was negatively correlated. Interestingly, 12 of the 15 studied nitrogen parameters, including total nitrogen, were not significantly correlated with MC. In contrast, three of the four studied phosphorus parameters, including total phosphorus, were positively related to MC. Results from this synthesis quantitatively reinforces the usefulness of commonly measured environmental parameters to monitor for conditions related to MC occurrence; however, correlational analyses by themselves are often ineffective and considering what role a parameter plays in the ecology of cyanobacterial blooms in addition to MC production is vital.

Application of a global age-coding system (“WRP”), based on molts and plumages, for use in demographic and other studies of birds

Abstract Determination of a bird’s age or cohort is critical for studies on avian demography, occurrence patterns, behavior, and conservation management. Age designations have largely been developed in north-temperate regions and utilize calendar-based or seasonally based codes; however, in tropical regions and in the southern hemisphere, these coding systems have limited utility at best. To address these issues, we had previously devised the “WRP system,” based on the nomenclature of Humphrey and Parkes (H–P) and Howell et al., which defines molts in an evolutionary context applicable to birds globally. Here we refine and build upon core concepts and definitions of the WRP coding system, resolving key limitations that were identified during its first decade of use. The WRP system employs a three-letter alpha code in which each letter describes a different aspect of H–P terminology: the molt cycle (which informs a bird’s age) and molt and plumage status within the cycle (each of which can also inform age). Here we recommend the continued use of most of the original (“core”) WRP coding while augmenting the system with an optional adjunct-code entry for comprehensiveness, clarity, and flexibility, and we clarify a few additional codes to cover less common molting and plumage strategies. For most users, from 7 to 13 core and 1 adjunct WRP code will be sufficient to describe all plumages and provide molt status and ages for demographic studies or other purposes. The revised WRP system is flexible enough to be adapted to the specific goals of programs while also providing core codes that can facilitate the comparison of avian age, molt, and plumage status on a global basis. We anticipate that our revised and standardized version of the WRP system will be easily adopted and could eventually replace calendar-based and seasonally based coding.

The singing question: re-conceptualizing birdsong.

Birdsong has been the subject of broad research from a variety of sub-disciplines and has taught us much about the evolution, function, and mechanisms driving animal communication and cognition. Typically, birdsong refers to the specialized vocalizations produced by oscines. Historically, much of the research on birdsong was conducted in north temperate regions (specifically in Europe and North America) leading to multiple biases. Due to these historic biases these vocalizations are generally considered to be highly sexually dimorphic, heavily shaped by sexual selection and essential for courtship and territoriality. Song is also typically defined as a learned trait shaped by cultural evolution. Together, this framework focuses research specifically on males, particularly during the north temperate breeding season - reflecting and thereby reinforcing this framework. The physiological underpinnings of song often emphasize the role of the hypothalamic-pituitary-gonadal axis (associated with breeding changes) and the song control system (underlying vocal learning). Over the years there has been great debate over which features of song are essential to the definition of birdsong, which features apply broadly to contexts outside males in the north temperate region, and over the importance of having a definition at all. Importantly, the definitions we use can both guide and limit the progress of research. Here, we describe the history of these definitions, and how these definitions have directed and restricted research to focus on male song in sexually selected contexts. Additionally, we highlight the gaps in our scientific knowledge, especially with respect to the function and physiological mechanisms underlying song in females and in winter, as well as in non-seasonally breeding species. Furthermore, we highlight the problems with using complexity and learning as dichotomous variables to categorize songs and calls. Across species, no one characteristic of song - sexual dimorphism, seasonality, complexity, sexual selection, learning - consistently delineates song from other songbird vocal communication. We provide recommendations for next steps to build an inclusive information framework that will allow researchers to explore nuances in animal communication and promote comparative research. Specifically, we recommend that researchers should operationalize the axis of variation most relevant to their study/species by identifying their specific question and the variable(s) of focus (e.g. seasonality). Researchers should also identify the axis (axes) of variation (e.g. degree of control by testosterone) most relevant to their study and use language consistent with the question and axis (axes) of variation (e.g. control by testosterone in the seasonal vocal production of birds).

Avian ecology and community structure across elevation gradients: The importance of high latitude temperate mountain habitats for conserving biodiversity in the Americas

Mountains are excellent systems for studying biodiversity as they promote rapid species turnover across relatively short elevational distances. Most research on biogeographic patterns in mountains has focused on tropical regions; far less is known about diversity across elevational gradients and their relative contribution to conservation in temperate mountains, particularly at high latitudes. To better understand the composition, ecology, and evolutionary history of high-latitude temperate mountain bird communities, we evaluated species richness, functional redundancy, and phylogenetic diversity across three elevation-specific habitats (upper montane, subalpine, alpine) in north temperate (9 mountains in British Columbia, Canada; 54°N) and south temperate (10 mountains in Chile; 39°S) regions representing distinct biogeographic origins. North temperate mountains had greater absolute species richness (77 versus 63 species), while south temperate mountains supported a greater proportion of the regional species pool (63% versus 44%). North temperate species richness increased with elevation to an ecotonal peak at treeline and then declined (subalpine = 58, alpine = 30 species), while the highest richness in south temperate mountains occurred at and above treeline (41 species). Similar species turnover patterns were observed in both systems with alpine habitats supporting the most distinct avifauna. Functional traits varied between regions with proportionally more migrants in the north, compared to more habitat specialists and cavity nesters in the south, particularly in the alpine. North temperate bird communities exhibited lower functional redundancy and higher total phylogenetic diversity, indicating a community susceptible to losing ecosystem functions and evolutionary potential. Southern communities contained greater functional redundancy and more evolutionarily isolated species, consistent with convergent evolution in challenging, high elevation habitats. Overall, in north temperate mountains, greater species richness and phylogenetic diversity, coupled with lower functional redundancy, particularly below treeline, highlights the importance of montane forests for biodiversity. In south temperate mountains, a distinct, speciose community at and above treeline, in combination with supporting a large proportion of the regional species pool, indicates a unique system with disproportionate conservation value. One-third of birds detected in north temperate mountains are considered of national or international conservation concern, compared to 9.5% of southern mountain birds. However, only 18% of the 63 species observed in the south temperate Andes (and only 5% of alpine species) have had a conservation status assessment. With increasing climate change and habitat loss pressures across elevations, temperate mountains in the Americas have significant conservation value and appear particularly important for maintaining regional biodiversity.

Cold tolerance varies among invasive populations of the Asian clam (Corbicula fluminea)

The distribution of the subtropical Asian clam (Corbicula fluminea (O.F. Müller, 1774)), one of the world’s most invasive freshwater molluscs, is reportedly constrained by a lower thermal tolerance limit of 2 °C. Although its occurrence in north temperate regions is typically restricted to artificially heated waterbodies, the species has been found to overwinter in unheated lakes and rivers. In laboratory experiments, we compared the cold tolerance of populations from several geographically distinct sites spanning 35°N to 46°N in eastern North America. Each population contained individuals that fully recovered from 2 months of continuous exposure to near-freezing (1 °C) conditions, contrary to published accounts of C. fluminea’s thermal ecology. Survivorship increased with body size and was enhanced by prior acclimation to a low temperature (10 °C) compared with a higher one (18 °C). When acclimated to 10 °C, clams from northern populations exhibited greater survivorship (55.0% ± 16.1%) than those from southern populations (26.7% ± 19.2%). However, one southern population demonstrated survivorship as great as that of the most tolerant northern population, suggesting that its clams could overwinter in unheated northern waterbodies. Differences among populations indicate either that contemporary evolution has occurred or that developmental plasticity shapes future acclimation responses.

The genome of Magnolia biondii Pamp. provides insights into the evolution of Magnoliales and biosynthesis of terpenoids

Magnolia biondii Pamp. (Magnoliaceae, magnoliids) is a phylogenetically, economically, and medicinally important ornamental tree species widely grown and cultivated in the north-temperate regions of China. Determining the genome sequence of M. biondii would help resolve the phylogenetic uncertainty of magnoliids and improve the understanding of individual trait evolution within the Magnolia genus. We assembled a chromosome-level reference genome of M. biondii using ~67, ~175, and ~154 Gb of raw DNA sequences generated via Pacific Biosciences single-molecule real-time sequencing, 10X Genomics Chromium, and Hi-C scaffolding strategies, respectively. The final genome assembly was ~2.22 Gb, with a contig N50 value of 269.11 kb and a BUSCO complete gene percentage of 91.90%. Approximately 89.17% of the genome was organized into 19 chromosomes, resulting in a scaffold N50 of 92.86 Mb. The genome contained 47,547 protein-coding genes, accounting for 23.47% of the genome length, whereas 66.48% of the genome length consisted of repetitive elements. We confirmed a WGD event that occurred very close to the time of the split between the Magnoliales and Laurales. Functional enrichment of the Magnolia-specific and expanded gene families highlighted genes involved in the biosynthesis of secondary metabolites, plant–pathogen interactions, and responses to stimuli, which may improve the ecological fitness and biological adaptability of the lineage. Phylogenomic analyses revealed a sister relationship of magnoliids and Chloranthaceae, which are sister to a clade comprising monocots and eudicots. The genome sequence of M. biondii could lead to trait improvement, germplasm conservation, and evolutionary studies on the rapid radiation of early angiosperms.

Responses of submerged macrophytes and periphyton to warming under two nitrogen scenarios: A microcosm study

Warming and higher nitrogen loading induced by increasing precipitation are expected scenarios in north temperate regions as consequence of global climate change, with potential effects on the functional traits of submerged macrophytes and periphyton. Using an experimental heating facility we investigated the responses of three-week growth of two submerged macrophytes (Potamogeton crispus Linn. and Elodea canadensis Michx.), and periphyton on these plants and their artificial mimics. Analysis was based on IPCC climate scenarios A2 (ca. + 3°C) and A2 + 50% (called A3 in our study) relative to ambient conditions, across warming in spring and early summer (summer showed higher nitrogen loading). Some functional traits of plants showed species-specific responses to warming: A3 promoted the growth of E. canadensis in both seasons, while for P. crispus warming reduced the leaf number in spring but enhanced the turion production in early summer. Periphyton biomass was lower in A3 in early summer, but not in spring. Our results further show that the growth of E. canadensis and the asexual reproduction of P. crispus might increase in a warmer future. Moreover, we found a complex response of periphyton to the temperature increase and substrate type, varying with season and nutrient state.

Forest edges and their effects on the arrival of dragonflies at north-temperate experimental ponds

The matrix, an environment in the landscape that individuals move through but do not reside in, can affect species dispersal and the arrival of individuals at habitat patches. Elements around this matrix that provide refuge or resources may shape the arrival of animals at habitat patches, even when those patches are equivalent in quality. Adult dragonflies (Odonata: Anisoptera) frequently use open terrestrial environments during movement and dispersal in north-temperate regions; however, they can also roost along forest edges. Because of the potential value of forest edges to adult dragonflies, we tested whether pond proximity (i.e., connectivity) to multiple forest edges was positively related to the abundance or diversity of arriving dragonflies. We observed dragonflies arriving at 9 experimental pond sites located within an open field landscape in Ontario, Canada. Experimental ponds differed in their distance to source ponds and to forest edges, a potential refuge for dragonflies. We found no effect of connectivity to forest edges or distance to source ponds on the abundance or diversity of dragonflies arriving at a site. Dragonfly dispersal was therefore not limited at the spatial scale of our study (<305 m to source ponds). In addition, dragonflies did not seem to discriminate among sites based on the amount of nearby forest edge, although all sites within the generally open landscape had at least some forest edge in close proximity (10–79 m). Our results provide greater insight regarding the decisions that dragonflies make in response to landscape elements while dispersing to reproductive habitats.

Analysis of structural differences and causes of ENSO temperature network

Based on the global surface temperature data, the global temperature correlation networks corresponding to El Niño and La Niña events are constructed respectively, and the differences in their effects on the network topological structure properties are analyzed. The results show that compared with the La Niña temperature network, the correlation between grid temperature series in El Niño temperature network is weakened, and the connectivity of the network is significantly reduced, especially in the tropical region and the southern temperate region. The network connectivity degree of equatorial eastern Pacific, equatorial western Pacific, equatorial Indian Ocean and equatorial Atlantic Ocean are relatively large, and the decrease in El Niño network is notable. They are also the four key regions leading to the differences of the structural characteristics of the two types of network. On this basis, the reason for the difference between the two types of network characteristics is preliminarily discussed. With the increase of SST in Niño3.4 region, the SST in equatorial eastern Pacific, equatorial Indian Ocean and other areas rise, which strengthenes outgoing long wave radiation and convection activities, and the interaction between low latitude and mid-latitude areas, and the variance of air temperature changes in the north and south temperate regions increase. As a result, the correlation between the temperature series of the four key regions and the rest of the world is weakened, therefore the connectivity of the global grid temperature network is reduced.

Diversification in Qinghai-Tibet Plateau: Orchidinae (Orchidaceae) clades exhibiting pre-adaptations play critical role

We explore the origins of the extraordinary plant diversity in the Qinghai-Tibetan Plateau (QTP) using Orchidinae (Orchidaceae) as a model. Our results indicate that six major clades in Orchidinae exhibited substantial variation in the temporal and spatial sequence of diversification. Our time-calibrated phylogenetic model suggests that the species-richness of Orchidinae arose through a combination of in situ diversification, colonisation, and local recruitment. There are multiple origins of species-richness of Orchidinae in the QTP, and pre-adaptations in clades from North Temperate and alpine regions were crucial for in situ diversification. The geographic analysis identified 29 dispersals from Asia, Africa and Europe into the QTP and 15 dispersals out. Most endemic species of Orchidinae evolved within the past six million years.

Cretaceous Diversity of the Relict Genus Alavesia Waters and Arillo (Diptera: Empidoidea: Atelestidae)

Alavesia has been known on the basis of five species in Late Cretaceous amber from Spain and Myanmar and two extant species from Namibia. Very recently, another extant species has been found in southern Brazil. Here we present a surprising diversity of Alavesia flies from the mid-Cretaceous of Myanmar (Late Albian-Early Cenomanian, ca. 99 Ma), including nine new species: A. angusta, sp. nov., A. brevipennae, sp. nov., A. lanceolata, sp. nov., A. latala, sp. nov., A. longicornuta, sp. nov., A. magna, sp. nov., A. pankowskiorum, sp. nov., A. spinosa, sp. nov., and A. zigrasi, sp. nov. The following new synonymy is proposed: NeoalavesiaPoinar and Vega, 2020 = AlavesiaWaters and Arillo, 1999. Notes are provided on an unusual structure, leg furrows found on femora to varying degrees among species, sometimes on tibiae, as well as notes on swarming behavior. Alavesia has undergone extensive extinction, a finding that further supports the relict nature of this genus and helps to explain the distribution of the other four Recent genera of Atelestidae, found in south and north temperate regions. Relict arthropod taxa preserved in Burmese amber are briefly reviewed, which also are narrowly endemic to temperate regions today.

Contribution to the knowledge of the bumblebee fauna of Afghanistan (Hymenoptera, Apidae, Bombus Latreille).

Bumblebees (Hymenoptera: Apidae: genus Bombus Latreille, 1802) constitute an important group of pollinators for many wild plants and crops in north temperate regions and South America. Although knowledge of these insects has been increasing over the last decades, some geographic areas remain poorly studied and additions to the knowledge of their faunas are infrequent. Afghanistan is one example of a country that is currently underrepresented in the scientific literature despite its high species diversity. For this study, more than 420 new occurrence records were gathered for 17 bumblebee species belonging to all eight subgenera recorded in the country, including the first record of a species closely related to the Blongipennis group. Additionally, the first standardized database for Afghan bees is launched, which we hope will be enriched in the future to allow further assessments of population trends for the bumblebees of Afghanistan. Finally, the previously published species records for the country are discussed considering the most recent taxonomic revisions of the genus and key perspectives are highlighted for further work in this understudied country and neighboring regions.

Konya Ekolojik Şartlarında Kültüre Alınan Umbelliferae Familyasına ait Bazı Tohumların Uçucu Yağ ve Sabit Yağ Bileşenlerinin Kimyasal Kompozisyonları

Apiaceae, also called Umbelliferae, the parsley family, in the order Apiales, comprising around 300 and 400 genera of plants distributed throughout a wide variety of habitats, principally in the north temperate regions of the world. Most members of Umbelliferae family are aromatic herbs. Species used as herbs and spices include fennel (Foeniculum vulgare), anise (Pimpinella anisum), dill (Anethum graveolens), coriander (Coriandrum sativum), and cumin (Cuminum cyminum). In this study, essential oil and crude oil components were determined in the seeds of dill, fennel, aniseed, cumin and coriander. The yield and components of essential oil and crude oil, main active compounds in the fruit of the plants of dill, fennel, anise, cumin and coriander grown in the ecological conditions of Konya were examined. According to the results, essential oil and crude oil yields were 3.5 % and 5.06 % in dill, 2.25 % and 22.07 % in anise, 2.70 % and 7.34 % in fennel, 1.90 % and 11.26 % in cumin, 0.95 % and 18.48 % in coriander. The main components of dill, fennel, anise, cumin and coriander seed essential oils were carvone (45.221 %), trans-anethole (86.898 %), (Z-)-Anethole (92.478 %), cumin aldehyde (42.900 %) and linalool (87.238 %) respectively. In crude oils, the main component was determined as C18:1 (oleic acid).

Characterization of the complete plastome of Alopecurus aequalis (Poaceae), a widespread weed

Alopecurus aequalis is a predominant weed species that distributes widely in North temperate regions. The complete plastome of A. aequalis is reported here. It is a circular molecular of 136,382 bp in length and consists of a large single-copy region (LSC: 80,455 bp), a small single-copy region (SSC: 12,849 bp), and two inverted repeats regions (IRs: 21,539 bp). GC content is 38.3%. This plastome encodes 112 unique genes, including 78 protein-coding genes, 30 tRNAs, and 4 rRNAs. Phylogenetic tree shows that A. aequalis is sister to Poa annua.

Zostera marina meadows in the northwestern Spain: distribution, characteristics and anthropogenic pressures

Zostera marina meadows represent an important marine ecosystem in the North temperate region. They are common in the northwestern Spain, but their distribution and biological traits remain poorly studied. Improving the knowledge of eelgrasses and identifying potential impact sources is necessary to implement conservation programs. Distribution, cover, density, size and presence of flowers in plants of Z. marina along the northwestern Spain were studied. Furthermore, we analyzed shifts in their distribution, the major human-mediated pressures (shellfishing activities) and their protection status. The study area was divided in 14 sectors that were sampled between 2014 and 2017. The northwestern Spain hosts the majority (61.5%, covering 5.8 km2, 48 meadows) of the total extension of Z. marina meadows in the Iberian Peninsula. Our study revealed 13 meadows that were not recorded before. Conversely, the disappearance of seven previously reported meadows was detected. Cover and density of Z. marina was 51.2% ± 15.1 (n = 180) and 181.1 shoots m−2 ± 79.6, respectively. Length and width of leaves were 41.9 cm ± 13.2 (n = 1800) and 6.3 mm ± 0.7, respectively. Although 98% of Z. marina meadows (5.7 km2) were located within marine protected areas, 80% of the meadows (4.7 km2) are subjected to anthropogenic pressures related to shellfishing activities. Z. marina meadows from the northwestern Spain are particularly relevant for the conservation of the species at its southern distribution limit and specific conservation and monitoring plans should be implemented to ensure its persistence. We propose 15 meadows to be considered in future conservation plans that were selected among the ones not included at present in protected areas, and considering their vulnerability and the presence of other species with interest for conservation.

A new methylene bisflavan-3-ol from the branches and leaves of Potentilla fruticosa

Dasiphora fruticosa L. (Rosaceae), also known as Potentilla fruticosa L. (syn.), is a hardy deciduous shrub widely distributed in the north temperate regions of the world. Three methylene bisflavan-3-ols (1-3), together with a procyanidin dimer, (-)-afzelechin-(4α→8)-(-)-afzelechin (4) were isolated for the first time from the branches and leaves of the titled plant, in addition to 11 known compounds (5-15). Their structures were elucidated by means of extensive spectroscopic analysis and by comparison with data reported in the literatures. Methylene 6,8-bis(7-O-glucosyl) catechin (1) was determined to be a new dimeric flavan-3-ol glycoside through a methylene linkage between C-8 and C-8 of two units. At a concentration of 128 μg/mL, the known compounds 9 – 13 exhibited antibacterial activities on Escherichia coli, Staphylococcus aureus subsp. aureus, Salmonella enterica subsp. enterica, and Pseudomonas aeruginosa. Compound 12 also showed certain glucose uptake stimulating activity.

Biomanipulating streams: a supplementary tool in lake restoration

Removal of cyprinid fish is a widely used biomanipulation tool to transform turbid shallow eutrophic lakes in north temperate regions into a clear water state. We here evaluate the removal of cyprinids from streams as a supplement to lake fishing. Since cyprinids often aggregate in high densities in lake inlet/outlet streams during winter migration, removal of fish in this space-confined habitat may be cost-efficient as compared to fish removal in the lake habitat. In two consecutive years, we annually removed up to 35% of the dominant cyprinids from an inlet stream to a lake and argue that this could easily be increased with a more targeted fishing effort. Concurrently, we monitored species- and length-specific variation in migration propensity, to explore how this relates to efficient fish removal. Smaller planktivores generally had a much higher migratory propensity than larger benthivores. Hence, stream fishing specifically targets species and size groups that are less efficiently controlled with traditional lake fishing methods. As a rule of thumb, stream fishing is most efficient when water temperature is 2–6°C. Prior to implementing fish removals from streams, the potential evolutionary consequences of the targeted removal of migratory phenotypes should be considered.