Where is the UK's pollinator biodiversity? The importance of urban areas for flower-visiting insects

Insect pollinators provide a crucial ecosystem service, but are under threat. Urban areas could be important for pollinators, though their value relative to other habitats is poorly known. We compared pollinator communities using quantified flower-visitation networks in 36 sites (each 1 km2) in three landscapes: urban, farmland and nature reserves. Overall, flower-visitor abundance and species richness did not differ significantly between the three landscape types. Bee abundance did not differ between landscapes, but bee species richness was higher in urban areas than farmland. Hoverfly abundance was higher in farmland and nature reserves than urban sites, but species richness did not differ significantly. While urban pollinator assemblages were more homogeneous across space than those in farmland or nature reserves, there was no significant difference in the numbers of rarer species between the three landscapes. Network-level specialization was higher in farmland than urban sites. Relative to other habitats, urban visitors foraged from a greater number of plant species (higher generality) but also visited a lower proportion of available plant species (higher specialization), both possibly driven by higher urban plant richness. Urban areas are growing, and improving their value for pollinators should be part of any national strategy to conserve and restore pollinators

Reporting HIV in Papua New Guinea: Trends and Omissions from 2000 to 2010

This article presents the findings from a longitudinal content analysis on the reporting of HIV (Human Immunodeficiency Virus) in Papua New Guinea’s two national newspapers—The National and Post-Courier—in 2000, 2005 and 2010. The authors tried to answer two key questions: Did press coverage of the disease increase and did the topics change or remain the same? Data from the content analysis showed that coverage of the disease increased significantly during the ten-year study period, and that the framing of the disease moved beyond representing HIV as purely a health story to one that was linked to socio-economic conditions and cultural practices. The feature stories gradually showed more sensitivity to people living with HIV, while they recognised and challenged the social stigma still associated with the disease in much of the countr

Practical methods for the control of tor-grass (Brachypodium pinnatum s.l.) and the restoration of calcareous grassland

Calcareous grasslands are sites of high conservation value across Western Europe; however, they are increasingly threatened by the dominance of a native competitive grass, Brachypodium pinnatum, which reduces the diversity of the grassland. Despite this, there is no clear consensus on the most effective method for controlling B. pinnatum and restoring the grassland community. We established two experiments at a calcareous grassland of high nature conservation value in the UK, i) a herbicide spraying experiment with seeding and ii) a seasonal cut-and-graze experiment, to investigate the potential for reducing dense B. pinnatum cover and preventing further expansion of sparse cover, respectively. We examined the effect of different herbicide and cut-and-graze treatments on B. pinnatum cover, and on the species richness and diversity of the grassland over three consecutive years. Herbicide spraying reduced the cover of B. pinnatum, though two spray applications led to a greater reduction longer-term. Species richness and diversity initially declined with the herbicide spray, however this recovered rapidly to levels higher than before spraying commenced. Seeding the spray plots was beneficial for the establishment of Bromopsis erecta and potentially reduced the likelihood of re-colonisation by B. pinnatum and undesirable arable species. The cut-and-graze experiment also showed promising potential in terms of controlling the spread of B. pinnatum. Compared with a single cut in the spring or autumn, cutting and grazing twice, in both spring and autumn was found to reduce the cover of B. pinnatum, whilst also increasing species richness and diversity. Further monitoring is needed to determine the long-term effectiveness of this management treatment

Addressing pollination deficits in orchard crops through habitat management for wild pollinators

There is increasing evidence that farmers in many areas are achieving below maximum yields due to insufficient pollination. Practical and effective approaches are needed to maintain wild pollinator populations within agroecosystems so they can deliver critical pollination services that underpin crop production. We established nesting and wildflower habitat interventions in 24 UK apple orchards and measured effects on flower-visiting insects and the pollination they provide, exploring how this was affected by landscape context. We quantified the extent of pollination deficits and assessed whether the management of wild pollinators can reduce deficits and deliver improved outcomes for growers over 3 years. Wildflower interventions increased solitary bee numbers visiting apple flowers by over 20%, but there was no effect of nesting interventions. Other pollinator groups were influenced by both local and landscape-scale factors, with bumblebees and hoverflies responding to the relative proportion of semi-natural habitat at larger spatial scales (1000 m), while honeybees and other flies responded at 500 m or less. By improving fruit number and quality, pollinators contributed more than £16 k per hectare. However, deficits (where maximum potential was not being reached due to a lack of pollination) were recorded and the extent of these varied across orchards, and from year to year, with a 22% deficit in output in the worst (equivalent to ~£14 k/ha) compared to less than 3% (equivalent to ~£2 k/ha) in the best year. Although no direct effect of our habitat interventions on deficits in gross output was observed, initial fruit set and seed set deficits were reduced by abundant bumblebees, and orchards with a greater abundance of solitary bees saw lower deficits in fruit size. The abundance of pollinators in apple orchards is influenced by different local and landscape factors that interact and vary between years. Consequently, pollination, and the extent of economic output deficits, also vary between orchards and years. We highlight how approaches, including establishing wildflower areas and optimizing the ratio of cropped and non-cropped habitats can increase the abundance of key apple pollinators and improve outcomes for growers

Functional identity versus species richness: herbivory resistance in plant communities

The resistance of a plant community against herbivore attack may depend on plant species richness, with monocultures often much more severely affected than mixtures of plant species. Here, we used a plant–herbivore system to study the effects of selective herbivory on consumption resistance and recovery after herbivory in 81 experimental grassland plots. Communities were established from seed in 2002 and contained 1, 2, 4, 8, 16 or 60 plant species of 1, 2, 3 or 4 functional groups. In 2004, pairs of enclosure cages (1 m tall, 0.5 m diameter) were set up on all 81 plots. One randomly selected cage of each pair was stocked with 10 male and 10 female nymphs of the meadow grasshopper, Chorthippus parallelus. The grasshoppers fed for 2 months, and the vegetation was monitored over 1 year. Consumption resistance and recovery of vegetation were calculated as proportional changes in vegetation biomass. Overall, grasshopper herbivory averaged 6.8%. Herbivory resistance and recovery were influenced by plant functional group identity, but independent of plant species richness and number of functional groups. However, herbivory induced shifts in vegetation composition that depended on plant species richness. Grasshopper herbivory led to increases in herb cover at the expense of grasses. Herb cover increased more strongly in species-rich mixtures. We conclude that selective herbivory changes the functional composition of plant communities and that compositional changes due to selective herbivory depend on plant species richness

Food for pollinators: quantifying the nectar and pollen resources of urban flower meadows

Planted meadows are increasingly used to improve the biodiversity and aesthetic amenity value of urban areas. Although many ‘pollinator-friendly’ seed mixes are available, the floral resources these provide to flower-visiting insects, and how these change through time, are largely unknown. Such data are necessary to compare the resources provided by alternative meadow seed mixes to each other and to other flowering habitats. We used quantitative surveys of over 2 million flowers to estimate the nectar and pollen resources offered by two exemplar commercial seed mixes (one annual, one perennial) and associated weeds grown as 300m2 meadows across four UK cities, sampled at six time points between May and September 2013. Nectar sugar and pollen rewards per flower varied widely across 65 species surveyed, with native British weed species (including dandelion, Taraxacum agg.) contributing the top five nectar producers and two of the top ten pollen producers. Seed mix species yielding the highest rewards per flower included Leontodon hispidus, Centaurea cyanus and C. nigra for nectar, and Papaver rhoeas, Eschscholzia californica and Malva moschata for pollen. Perennial meadows produced up to 20x more nectar and up to 6x more pollen than annual meadows, which in turn produced far more than amenity grassland controls. Perennial meadows produced resources earlier in the year than annual meadows, but both seed mixes delivered very low resource levels early in the year and these were provided almost entirely by native weeds. Pollen volume per flower is well predicted statistically by floral morphology, and nectar sugar mass and pollen volume per unit area are correlated with flower counts, raising the possibility that resource levels can be estimated for species or habitats where they cannot be measured directly. Our approach does not incorporate resource quality information (for example, pollen protein or essential amino acid content), but can easily do so when suitable data exist. Our approach should inform the design of new seed mixes to ensure continuity in floral resource availability throughout the year, and to identify suitable species to fill resource gaps in established mixes

Influence of fungivorous soil organisms and fungicides on the demography of seed-populations in the soil

The seeds of many plant species form seed banks in the soil to synchronise seedling emergence with the occurrence of favourable conditions for plant establishment. This adaptation to reduce seedling mortality does however come at a cost, as it increases the probability of mortality at the seed stage, for example through decomposition by micro-organisms, among which saprophytic fungi deserve special mention.Within this PhD project, two literature reviews were carried out to document the current state of research regarding the influence of these fungi on the demography of buried seeds, and regarding the interactions between soil fungi and the soil mesofauna. Based on these literature reviews, hypotheses were derived to be tested in the experimental part of my PhD project.Seed burial studies carried out across a range of ecosystems to compare the demographic fates of fungicide-treated seeds and of untreated seeds have demonstrated a negative effect of such fungi on the longevity of buried seeds. Soil fungi themselves are consumed by a wide range of soil-dwelling animals. It seems possible that the fungivorous soil mesofauna, through its feeding activity, may be able to reduce fungal attack of seeds buried in the soil, and thus to increase seed survival.In two experiments I investigated whether this can indeed be the case. The first experiment was carried out under constant environmental conditions conducive to both the growth of soil fungi and the reproduction of collembolans, and at the same time inhibitive to seed germination. This experiment was conducted in Petri dish à ¯Ã ¿Ã ½microcosmsà ¯Ã ¿Ã ½ containing soil and the seeds of four different grassland plant species. At the beginning of a five-week incubation period, individuals of the collembolan Protaphorura fimata were added to a subset of Petri dishes. This resulted in an increase in the number of viable ungerminated seeds at the end of the experiment in three of the species, Centaurea nigra, Dactylis glomerata and Origanum vulgare. In a subsequent field experiment I used perforated steel cylinders lined with gauze and filled with defaunated soil and seeds of 3 grassland plant species as experimental mesocosms, which were buried in autumn. I tested whether similar results to those observed in the first experiment under lab conditions would be found with respect to seedling emergence under field conditions. Again, P. fimata was added to a subset of these mesocosms. Both in C. nigra and in O. vulgare seedling emergence was significantly higher in the presence of added P. fimata. The results of these two experiments allow the conclusion that the fungivorous soil mesofauna may potentially affect plant species composition by promoting some species via a reduction in fungal-induced seed mortality, but not others. In a third experiment I investigated whether methodological variations with respect to use and combination of different fungicides would be able to affect levels of seed mortality attributed to fungal-induced seed decomposition, and also whether dormancy levels, and thus the readiness of seeds to germinate, would be affected by fungicide treatments. For this purpose, in autumn the seeds of three grassland plant species were treated with up to three different fungicides (captan, iprodione and mancozeb) alone and in combination - an untreated control treatment was also included - and buried in the field using seed bags made of nylon stockings. In the following spring, after retrieval of the seed bags, I used germination tests and tetrazolium viability testing to determine levels of seed mortality during the burial period. In two species, Daucus carota and Anthriscus sylvestris, the combination of two fungicides generally resulted in a lower mortality than use of a single fungicide. However, in Daucus the use of all three fungicides in combination generally resulted in a slightly higher mortality than the use of just two fungicides in combination. The use of mancozeb resulted in a longer-lasting increase in dormancy levels in Daucus, whereas a similar effect on seed dormancy in Centaurea nigra was more short-lived. As these effects on seed mortality and dormancy were both species-specific and fungicide-specific, I recommend to conduct pilot studies to investigate such fungicide effects before an actual seed burial study is carried out, and to do so particularly when a study is designed with the aim to measure in situ seedling emergence

Zum Einfluss von fungivoren Bodenorganismen und Fungiziden auf die Demografie von Samen-Populationen im Boden

The seeds of many plant species form seed banks in the soil to synchronise seedling emergence with the occurrence of favourable conditions for plant establishment. This adaptation to reduce seedling mortality does however come at a cost, as it increases the probability of mortality at the seed stage, for example through decomposition by micro-organisms, among which saprophytic fungi deserve special mention.Within this PhD project, two literature reviews were carried out to document the current state of research regarding the influence of these fungi on the demography of buried seeds, and regarding the interactions between soil fungi and the soil mesofauna. Based on these literature reviews, hypotheses were derived to be tested in the experimental part of my PhD project.Seed burial studies carried out across a range of ecosystems to compare the demographic fates of fungicide-treated seeds and of untreated seeds have demonstrated a negative effect of such fungi on the longevity of buried seeds. Soil fungi themselves are consumed by a wide range of soil-dwelling animals. It seems possible that the fungivorous soil mesofauna, through its feeding activity, may be able to reduce fungal attack of seeds buried in the soil, and thus to increase seed survival.In two experiments I investigated whether this can indeed be the case. The first experiment was carried out under constant environmental conditions conducive to both the growth of soil fungi and the reproduction of collembolans, and at the same time inhibitive to seed germination. This experiment was conducted in Petri dish à ¯à ¿à ½microcosmsà ¯à ¿à ½ containing soil and the seeds of four different grassland plant species. At the beginning of a five-week incubation period, individuals of the collembolan Protaphorura fimata were added to a subset of Petri dishes. This resulted in an increase in the number of viable ungerminated seeds at the end of the experiment in three of the species, Centaurea nigra, Dactylis glomerata and Origanum vulgare. In a subsequent field experiment I used perforated steel cylinders lined with gauze and filled with defaunated soil and seeds of 3 grassland plant species as experimental mesocosms, which were buried in autumn. I tested whether similar results to those observed in the first experiment under lab conditions would be found with respect to seedling emergence under field conditions. Again, P. fimata was added to a subset of these mesocosms. Both in C. nigra and in O. vulgare seedling emergence was significantly higher in the presence of added P. fimata. The results of these two experiments allow the conclusion that the fungivorous soil mesofauna may potentially affect plant species composition by promoting some species via a reduction in fungal-induced seed mortality, but not others. In a third experiment I investigated whether methodological variations with respect to use and combination of different fungicides would be able to affect levels of seed mortality attributed to fungal-induced seed decomposition, and also whether dormancy levels, and thus the readiness of seeds to germinate, would be affected by fungicide treatments. For this purpose, in autumn the seeds of three grassland plant species were treated with up to three different fungicides (captan, iprodione and mancozeb) alone and in combination - an untreated control treatment was also included - and buried in the field using seed bags made of nylon stockings. In the following spring, after retrieval of the seed bags, I used germination tests and tetrazolium viability testing to determine levels of seed mortality during the burial period. In two species, Daucus carota and Anthriscus sylvestris, the combination of two fungicides generally resulted in a lower mortality than use of a single fungicide. However, in Daucus the use of all three fungicides in combination generally resulted in a slightly higher mortality than the use of just two fungicides in combination. The use of mancozeb resulted in a longer-lasting increase in dormancy levels in Daucus, whereas a similar effect on seed dormancy in Centaurea nigra was more short-lived. As these effects on seed mortality and dormancy were both species-specific and fungicide-specific, I recommend to conduct pilot studies to investigate such fungicide effects before an actual seed burial study is carried out, and to do so particularly when a study is designed with the aim to measure in situ seedling emergence

Diet of the lesser horseshoe bat (Rhinolophus hipposideros) in central Germany and its seasonal and site-specific variation

As a K-strategist and comparatively sedentary species, the lesser horseshoe bat Rhinolophus hipposideros is considered sensitive to changes in habitat quality. Knowledge of the species’ dietary requirements and use of foraging habitats is thus considered an essential prerequisite to manage its habitats adequately. Based on four large annual samples of faecal pellets from three different nursery colonies, covering the main foraging season, and including two consecutive years of sampling from one colony, we studied the diet of Central German populations of R. hipposideros. Consistent with findings of similar studies carried out in other parts of the distribution range of R. hipposideros, in our study, Diptera, Lepidoptera, and Neuroptera represented the most important groups of prey for the studied colonies. However, Hemiptera made a comparatively larger contribution in our study than in others, and so did Hymenoptera in one of the colonies. We found seasonal compositional variation in all four annual samples, as well as compositional variation between samples from different colonies, but not between the two annual samples obtained in consecutive years from the same colony. Differences between colonies appeared at least to some extent to reflect differences in availability of foraging habitats. Our results are thus in agreement with the assumption of R. hipposideros being a largely opportunistic, generalist forager. Our findings are also consistent with a known preference by R. hipposideros of woodland as main foraging habitat, as previously established by other studies carried out in the northern part of the distribution range. However, the relative importance of Hemiptera, and in particular of Psyllidae, at certain times during the foraging season, suggests that the Central German colonies of R. hipposideros might have utilized commercial orchards and private fruit gardens for foraging during seasonal peaks in abundance of pest species of fruit trees. The implied ability of R. hipposideros to respond to seasonal abundance peaks of particular groups of prey in a range of habitats suggests that structural diversity might be key in maintaining viable populations of this species. The potential importance of orchards and fruit gardens in regions where such habitats are prevalent is likely to have relevant management implications

Soil microbial effects on weed seedbank persistence: current knowledge and applications for weed management

Chapter 13. The use of microbe–seed interactions for weed management has been variously discussed over the last few decades, and soil microbes have been demonstrated to play an important role in affecting weed seedbank persistence and weed demography. However, very few weed management applications based on such interactions have so far been successfully tested under field conditions. This chapter provides an up-to-date summary of what is known about direct interactions between buried weed seeds and soil-borne microbes. The principal mechanisms of microbial attack of seeds, the roles of abiotic environmental factors and of biotic interactions in modulating microbe–seed interactions, and seed defence mechanisms underlying weed seed resistance to microbial decay are herein discussed. In addition, how these different aspects can affect weed management applications, via soil inoculation with seed-pathogenic microbes, the manipulation of environmental conditions to promote seed decay processes, and the weakening of seed defences against microbial attack is also discussed. These approaches can be deployed alone or in combination, but combinational approaches may be more promising when designing weed management applications. As shown in this chapter, due to the availability of modern molecular microbial methods, remarkable progress has been made in understanding seed defences and defence syndromes and mechanisms of microbial attack. However, the underlying processes in the field are still only very poorly understood, and a more detailed conceptual framework of how soil-borne seed-decaying microorganisms, weed seeds and their seed-borne microflora, and their environment interact with each other must be developed to facilitate the development of more reliable weed management options