Invasive knotweed modifies predator–prey interactions in the soil food web

Biological Invasions - Invasive plants often modify the structure of the community of native plants and animals, but their potential impact on the plant–soil interface is poorly studied. In...     

Consumer–resource dynamics of indirect interactions in a mutualism–parasitism food web module

Food web dynamics are well known to vary with indirect interactions, classic examples including apparent competition, intraguild predation, exploitative competition, and trophic cascades of food chains. Such food web modules entailing predation and competition have been the focus of much theory, whereas modules involving mutualism have received far less attention. We examined an empirically common food web module involving mutualistic (N ₂) and parasitic (N ₃) consumers exploiting a resource of a basal mutualist (N ₁), as illustrated by plants, pollinators, and nectar robbers. This mutualism–parasitism food web module is structurally similar to exploitative competition, suggesting that the module of two consumers exploiting a resource is unstable. Rather than parasitic consumers destabilizing the module through (?,?) indirect interactions, two mechanisms associated with the mutualism can actually enhance the persistence of the module. First, the positive feedback of mutualism favors coexistence in stable limit cycles, whereby (+,?) indirect interactions emerge in which increases in N ₂ have positive effects on N ₃ and increases in N ₃ have negative effects on N ₂. This (+,?) indirect interaction arising from the saturating positive feedback of mutualism has broad feasibility across many types of food web modules entailing mutualism. Second, optimization of resource exploitation by the mutualistic consumer can lead to persistence of the food web module in a stable equilibrium. The mutualism–parasitism food web module is a basic unit of food webs in which mutualism favors its persistence simply through density-dependent population dynamics, rather than parasitism destabilizing the module.     

What Maintains the Central North Pacific Genetic Discontinuity in Pacific Herring?

Pacific herring show an abrupt genetic discontinuity in the central North Pacific that represents secondary contact between refuge populations previously isolated during Pleistocene glaciations. Paradoxically, high levels of gene flow produce genetic homogeneity among ocean-type populations within each group. Here, we surveyed variability in mtDNA control-region sequences (463 bp) and nine microsatellite loci in Pacific herring from sites across the North Pacific to further explore the nature of the genetic discontinuity around the Alaska Peninsula. Consistent with previous studies, little divergence (Φ_ST  = 0.011) was detected between ocean-type populations of Pacific herring in the North West Pacific, except for a population in the Yellow Sea (Φ_ST  = 0.065). A moderate reduction in genetic diversity for both mtDNA and microsatellites in the Yellow Sea likely reflects founder effects during the last colonization of this sea. Reciprocal monophyly between divergent mtDNA lineages (Φ_ST  = 0.391) across the Alaska Peninsula defines the discontinuity across the North Pacific. However, microsatellites did not show a strong break, as eastern Bering Sea (EBS) herring were more closely related to NE Pacific than to NW Pacific herring. This discordance between mtDNA and microsatellites may be due to microsatellite allelic convergence or to sex-biased dispersal across the secondary contact zone. The sharp discontinuity between Pacific herring populations may be maintained by high-density blocking, competitive exclusion or hybrid inferiority.     

TMEM8 – a non-globin gene entrapped in the globin web

For more than 30 years it was believed that globin gene domains included only genes encoding globin chains. Here we show that in chickens, the domain of α-globin genes also harbor the non-globin gene TMEM8. It was relocated to the vicinity of the α-globin cluster due to inversion of an ∼170-kb genomic fragment. Although in humans TMEM8 is preferentially expressed in resting T-lymphocytes, in chickens it acquired an erythroid-specific expression profile and is upregulated upon terminal differentiation of erythroblasts. This correlates with the presence of erythroid-specific regulatory elements in the body of chicken TMEM8, which interact with regulatory elements of the α-globin genes. Surprisingly, TMEM8 is not simply recruited to the α-globin gene domain active chromatin hub. An alternative chromatin hub is assembled, which includes some of the regulatory elements essential for the activation of globin gene expression. These regulatory elements should thus shuttle between two different chromatin hubs.     

A trophic cascade in a macrophyte-based food web at the land–water ecotone

Trophic cascades may purportedly be more common in aquatic than terrestrial food webs, but herbivory on freshwater vascular plants has historically been considered low. Water lilies are an exception, suffering severe grazing damage by leaf beetles. To test whether a central prediction of cascade models—that predator effects propagate downwards to plants—operates in a macrophyte-based food web, we experimentally manipulated predation pressure on a key herbivore of water lilies in the littoral zone of a lake in Michigan, USA. Field experiments comprised combinations of caging treatments to alter the number of predators (larvae of the ladybird beetle Coleomegilla maculata) that hunt the grazers of the macrophytes (larvae of the leaf beetles Galerucella nymphaeae) on the leaves of the water lily Nuphar advena. Predatory larvae of the ladybird beetles significantly reduced grazing damage to water-lily leaves by 35–43%. The predators reduced plant damage chiefly via density-mediated effects, when lower densities of grazers translated to significant declines in plant damage. Plant damage caused by the surviving herbivores was less than predicted from individual grazing rates under predator-free conditions. This suggests that trait-mediated effects may possibly also operate in this cascade. The observed strong effect of predators on a non-adjacent trophic level concurs with an essential component of the trophic cascade model, and the cascade occurred at the ecotone between aquatic and terrestrial habitats: Nuphar is an aquatic macrophyte with emergent and floating leaves, whereas both beetle species are semi-terrestrial and use the dry, emergent and floating leaves of the water lily as habitat. Also, the cascade is underpinned by freshwater macrophytes—a group for which trophic processes have often been underappreciated in the past.     

Human–vegetation interactions during the Holocene in North America

Vegetation History and Archaeobotany - Between the initial colonization of North America and the European settlement period, Indigenous American land use practices shaped North American landscapes...     

Upwelling-like bottom intrusion enhances the pelagic–benthic coupling by a fish predator in a coastal food web

Upwelling regions where nutrients are transported from deep to surface waters are among the most productive in the oceans. Although it is well known that the upwelling affects fishery production through bottom-up trophic cascading, it remains unexplored how temporal variation in its intensity alters overall trophic energy flows within a focal food web. In the present study, we demonstrate that inter-annual variation in the intensity of upwelling-like bottom intrusion alters food web properties in coastal waters of the Uwa Sea by focusing on the levels of δ¹³C and δ¹⁵N for a demersal fish predator, Acropoma japonicum. This approach integrates information on prey–predator interactions. In the season following a stratification period when pelagic productivity is limited by nutrient availability, A. japonicum showed lower levels of δ¹³C in years with high bottom intrusion intensity than in those with low intensity. One possible cause for this isotopic depletion is that the bottom intrusion-induced nutrient supply enhances pelagic productivity and consequently facilitates a foraging shift by A. japonicum from ordinary benthic prey to supplementary pelagic prey with a lower δ¹³C. In conclusion, the increased intensity of bottom intrusion results in coupling of two major trophic energy flows, pelagic and benthic food chains, through the demersal predator’s foraging shift.     

Investigation on the role of nsSNPs in HNPCC genes – a bioinformatics approach

Background  

A central focus of cancer genetics is the study of mutations that are causally implicated in tumorigenesis. The identification of such causal mutations not only provides insight into cancer biology but also presents anticancer therapeutic targets and diagnostic markers. Missense mutations are nucleotide substitutions that change an amino acid in a protein, the deleterious effects of these mutations are commonly attributed to their impact on primary amino acid sequence and protein structure.     

Eliminating driftnets from the North Pacific Ocean: U.S.—Japanese cooperation in the international North Pacific Fisheries Commission, 1953–1993

Japanese negotiators agreed to eliminate driftnet fishing for salmon in the North Pacific Ocean by the end of 1992. The Japanese high seas fishing fleet for salmon had been an economically valuable yet environmentally destructive operation for four decades. The Japanese government progressively phased out lucrative Japanese salmon fishing operations in the North Pacific, apparently capitulating to U.S. pressure. No U.S. enforcement with punitive sanctions proved necessary, however. Specific characteristics of the international market created the possibility of an environmentally benign international agreement. International integration of the market for fisheries products was made possible by the high market value of salmon in the United States and in Japan. In the 1970s, foreign direct investment from vertically integrated, Tokyo‐based fishing firms into canning and processing operations in Alaska and the Pacific Northwest facilitated U.S. Japanese agreement. The high existence (nonuse) value of marine mammals in the United States was also an important factor.     

Ornithology and bird conservation in North America – a Canadian perspective

Capsule A comparison between North American and European ornithology shows many differences between the two.

While local knowledge was developed over millennia in Europe, in North America much was originally learned from the indigenous people. Knowing the food value of wild game was essential to survival and led to a strong tradition of wildlife management in North America. However, there was also systematic exploration of the local avifauna by museum-based collectors. This dual origin of ornithology is still detectable today. North American ornithology, particularly through the introduction of the Migratory Birds Convention Act of 1917, is strongly influenced by federal, state and provincial governments who have a statutory responsibility for the protection of wild birds. Because the USA and Canada, and more recently Mexico, are responsible for the administration of the Act, many initiatives in bird conservation involve international co-operation, starting initially with the North American Waterfowl Management Plan, but now extended to all species of birds. Many partnerships involving government, professional and amateur ornithologists (e.g. Bird Studies Canada) have resulted in monitoring of bird populations similar to that done by the BTO. However, there still seems to be a paucity of population studies and survey information in the mainstream ornithological journals in North America.     

Fisheries-Led Development in the South Pacific: Charting a “Pacific Way” to a Sustainable Future

Considerable debate surrounds the appropriate mix of policies to drive fishing-led development among the developing nations in the South Pacific. Since the 1970s, South Pacific small island states have committed themselves to policies of tuna industry domestication, but serious doubts have emerged as to whether these can deliver improvements to the well-being of Pacific peoples. An alternative policy approach has been suggested by development economists that would see Pacific Island nations largely abandon direct involvement in the industry and return to collective efforts to secure reasonable access fees from distant water fishing nations that take the majority of the region's tuna catches. This article argues that one reason that this policy shift has not been taken is that tuna industry domestication policies remain bound up within the influential discourse of “resource nationalism.” It is contended that any movement toward a more environmentally and developmentally sustainable ocean fisheries policy will require close engagement and transformation of this sovereignty-focused narrative.     

Assessment of cetacean–fishery interactions in the marine food web of the Gulf of Taranto (Northern Ionian Sea,Central Mediterranean Sea)

Reviews in Fish Biology and Fisheries - The exploitation of fishery resources acts as a driving force on cetaceans both directly, by determining their fishing mortality or injury as by-catch...     

Untangling the aphid-parasitoid food web in citrus: Can hyperparasitoids disrupt biological control?

Molecular techniques are irreplaceable to untangle the trophic links in communities where immature entomophagous species (either in the third or fourth level) develop inside the phytophagous. This is the case of aphid-parasitoid communities. Here, we develop a DNA-based approach to untangle the structure of the aphid-parasitoid food web in citrus, where Aphis spiraecola Patch. (Hemiptera: Aphididae) is a key pest and Binodoxys angelicae Haliday (Hymenoptera: Braconidae), its dominant primary parasitoid, is attacked by a complex of hyperparasitoids. Aphid populations and parasitism were followed at weekly intervals in 2012 and 2013. Parasitism rates were low (∼0.04 in the four sampled orchards). Simultaneously, colonies harboring aphid mummies were collected. Approximately half of the mummies were reared to adulthood and at least six hymenopteran hyperparasitoid species were identified by classical means: Syrphophagus aphidivorus (Mayr) (Encyrtidae), Alloxysta sp. (Forster) (Figitidae), Asaphes sp. (Walker) (Pteromalidae), Pachyneuron aphidis (Bouché) (Pteromalidae), Dendrocerus sp. (Ratzeburg) (Megaspilidae) and Phaenoglyphis villosa (Hartig) (Figitidae). The other half was subjected to a Taqman-based multiplex PCR to investigate trophic relationships in this food web. We confirmed that all six species hyperparasitized B. angelicae. The most abundant hyperparasitoids were S. aphidivorus and Alloxysta sp. Both were abundant from the beginning of the season, and hyperparasitism rates remained high (∼0.4) throughout the season in the two study years. Although these species could share the same mummy, S. aphidivorus and Alloxysta sp. were the most abundant species and dominated this food web. Finally, hyperparasitoids also increased the secondary sex ratio of B. angelicae. Thus, hyperparasitism probably explains the low impact of B. angelicae on A. spiraecola populations.     

Methods to characterize the structure of food powders – a review

Food powders can exist in amorphous, crystalline or mixed structure depending on the order of molecular arrangement in the powder particle matrices. In food production, the structure of powders has a greatly effect on their stability, functionality, and applicability. The undesirable structure of powders can be accidentally formed during production. Therefore, characterization of powder structure as well as quantification of amorphous–crystalline proportions presenting in the powders are essential to control the quality of products during storage and further processing. For these purposes, many analytical techniques with large differences in the degree of selectivity and sensitivity have been developed. In this review, differences in the structure of food powders are described with a focus being placed on applications of amorphous powders. Essentially, applicability of common analytical techniques including X-ray, microscopic, vapor adsorption, thermal, and spectroscopic approaches for quantitative and qualitative structural characterization of food powders is also discussed.     

Tourism sustainability in Tibet – Forward planning using a systems approach

The purpose of this study is to employ a nonlinear dynamic evaluation method to assess the tourism sustainability of Tibet Autonomous Region (TAR), China, a new emerging tourism destination. The methodology draws on system dynamics and Back Propagation (BP) neural network. According to 7 setting principles, this study identifies 13 tourism sustainability indicators including conventional tourism income, tourism resources stock, pollution stock, etc., as well as specific residents’ tourism cognition, seasonal difference, accessibility, etc. Then a system dynamics model including the 13 indicators (variables) and other relevant auxiliary variables is established. Based on the numerical simulation, using a three layers BP neural network optimized by genetic algorithm and particle swarm algorithm, this study evaluates the future sustainability dynamically and compares the sustainability evolution from 2014 to 2050 under different development strategies. The research results not only provide information useful for the dynamic control and scientific management of the future sustainable tourism development, but also provide a systems approach to evaluate regional tourism sustainability.     

Microbe–microbe interactions in mixed culture food fermentations

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Highlights► Microbial interactions in food fermentations are crucial for product functionality. ► Complex microbial consortia tolerate more variation in the environment. ► Knowledge of communities of fermenting microbes drives diversification of starter cultures. ► Use of complex starter cultures requires new propagation methodologies. ► Immobilised cell technology is a high potential solution for propagating complex cultures.     

Biomarker response and therapy prediction in renal denervation therapy – the role of MR-proadrenomedullin in a multicenter approach

Background: Renal denervation has been proposed as a therapeutic option in patients with resistant hypertension. Circulating blood borne biomarkers might be helpful to identify individuals responding to RDN therapy. MR-proADM is a strong prognostic marker in patients with cardiovascular disease. The aim of this multicenter study was to evaluate the effect of RDN on MR-proADM concentrations.

Methods and results: We measured MR-proADM, BNP, and MR-proANP in 110 patients before and after RDN in a multicenter setting. All patients were followed up after 1 and 6 months by office and ambulatory blood pressure (BP) measurements. The mean office BP decreased from 165/89 to 152/87?mmHg 6 months after RDN (systolic: p?<?0.001; diastolic: ns), the responder-rate was 74%. Intriguingly MR-proADM concentrations increased from 0.66 to 0.69?nmol/L (p?<?0.001) and were significantly associated with reduction of systolic office BP after 6 months in multivariate analyses (coefficient ?0.0018, p?<?0.001). In therapy-responders MR-proADM concentrations showed a significantly higher increase over time (coefficient 0.0105, p?<?0.05), as compared to non-responders. There were no significant differences in BP change for individuals with low and high baseline MR-proADM (BP-Delta low MR-proADM ?23/?4?mmHg vs. high MR-proADM ?24/?5?mmHg). The natriuretic biomarkers BNP and MR-proANP did not change significantly after 6 months. Biomarkers at baseline were not able to predict for therapy-responder.

Conclusion: In patients undergoing RDN, baseline measurements of various biomarkers had no prognostic use for therapy success in this short time follow-up period in a multicenter approach. Intriguingly, MR-proADM showed a significant association with BP reduction after 6 months.     

Development of a spatially explicit approach for mapping ecosystem services in the Brazilian Savanna – MapES

The objective of the presented study is the development of a spatially explicit approach for mapping ecosystem services (MapES) by using specific knowledge about the Cerrado biome (Brazilian Savanna). This biome covers an area of about 2 million km², i.e. nearly 24% of the total area of Brazil, and has come under substantial pressure during the last 50 years caused by strong land-use/land-cover change, mostly due to agricultural expansion and urbanization. Because of its fast transformation rate, there is an enormous demand for knowledge, and its application, about the effects of land-use/land-cover on the capacity of providing or maintaining ecosystem services. The MapES approach was developed using a vast existing knowledge base. After analyzing and structuring this knowledge the relationships between land-use/land-cover and the potential to provide or maintain eight ecosystem services (Erosion Control, Runoff Control, Water Supply, Water Quality Maintenance, Soil Quality Maintenance, Biodiversity Maintenance, Food Production and Energy Production) were parametrized. In addition, the approach was developed as spatially explicit by including landscape properties (soil, slope and distance to river network) in the cell based system. A reference map of potential natural vegetation and a land use map for 2013 for a meso-scale experimental catchment (32.7 km²) were produced. The catchment was used as an example to apply the approach, i.e. assessing and visualizing changes from before human interference to the current land use situation. Finally, a procedure for assessing the potential impacts of land-use/land-cover on ecosystem services considering the methodological limitations of the respective monitoring. The presented approach is easy to understand, to modify and to adapt to other situations and might be therefore used in other context of decision support. It might also help to fill the gap between land use planning and numeric modeling using very complex tools.