Earlier flowering times. A survey has shown that plants are flowering earlier in the year.  Cambridge University researchers compared the dates of flowering of some four hundred plus species before and after 1986. They found that plants are now flowering roughly one month earlier.  More recent decades have been associated with rising air temperatures. This change in flowering time may have profound consequences for the plants.  The vast majority of plants are dependent on pollinating insects (bees, bumblebees, hoverflies) to set seed and complete their life cycles.  By flowering early their cycle, plants may not match up  with the activities of their pollinators. They may flower but their pollinators bee ‘missing’. Their pollinators need to emerge from their overwintering stage earlier. Earlier flowering may not matter for those plants that are visited by several pollinators but for those that are dependent on one or two specific visitors - it may critical.  For example, Sainfoin.  Sainfoin is host to a particular (solitary) bee Melitta dimidiata (remote image here).   It is a monolectic bee; i.e., a bee that collects food (nectar and pollen) from only one species of flower - the sainfoin.  If the sainfoin flowers earlier in the year and the bee does not match the shift in flowering, then the bee has a problem. Work on the effects of climate change on pollinators has been somewhat limited to date, but studies in Japan suggest that bees / bumblebees are somewhat behind plants in their response to environmental changes. Bee and bumblebee news. Recent research data provide evidence that (buff tailed) bumblebees are not able to detect or avoid concentrations of pesticides [imidacloprid, thiamethoxam, clothianidin, or sulfoxaflor], as used ‘on the farm’ - from signals sent by their mouthparts. The mouthparts are covered with tiny hairs and these hairs have ‘pores’ in them. Chemicals pass through these ‘pores’ to sensory cells; this is how the bee tastes and smells. It seems likely that the bumblebees are at considerable risk of consuming pesticides in their search for nectar when visiting pesticide-treated crops. [caption id="attachment_19675" align="alignleft" width="300"] Bumbles foraging in artichoke[/caption] Another agrochemical,  Roundup,  has been found to affect the learning and memory of bumblebees. Roundup, which contains glyphosate, affects their ability to learn and memorise connections between colour and taste.  Impaired colour vision is likely to affect the foraging and nesting success of the bees.  The research was conducted in Finland by researchers at the University of Turku. In yet another concerning study, researchers at the University of Maryland have found that the life span of laboratory-raised honey bees has reduced considerably.    Five decades ago, the lifespan for a worker honeybee (Apis mellifera) under controlled laboratory conditions was about 34 days. Now it is some 17/ 18 days - according the report in Nature.  The study also reviewed the scientific literature [from the 1970s to now] and noted a trend in the life span of bees.   Shortened worker bee lifespan has implications for colony health and survivorship.  The work at the University of Maryland is ongoing. Methane release. Ghost forests are found in coastal areas.  As a consequence of climate change, sea water has ‘invaded’ low laying areas and trees have died. The dead trees are sometimes referred to as ‘snags.  A  number of woodland / forest communities along the eastern coast of the United States have been affected.  Recent work by North Carolina State University has shown that these ghost forests release methane.  The methane is generated by bacteria in the soil but then ‘escapes’ by means of the ‘snags’.  As it passes through the wood of the ‘snags’, microbes may consume and alter the methane.   As methane is a potent greenhouse gas, understanding the nature and extent of these methane emissions from ‘ghost forests’ is important. Tree rings The study of tree rings has been invaluable in dating many historic objects ./ archaeological sites.  Now, it seems that they could play a role in estimating the amount of carbon that trees are actually absorbing (carbon sequestration), if woodland / forest inventories are coupled with core samples of the trees. The measurement of the annual rings from such cores could create a record of ‘tree growth across space and time’, yielding a more accurate estimate of the amount of carbon being taken up by woodland and forests. Forests, soils and oceans are major ‘carbon sinks’.

Electric bees ? Both bumblebees and flowers carry an electric charge.  Flowers have a weak negative charge, whilst the bees have a positive charge.  The attraction between these two opposing electric fields may help the bees sense flowers.  The electric charge of a bee may even stimulate a flower to release a burst of scent, aka volatile organic compounds.  This was true for petunias, but not snapdragons.  When a bee has visited a flower, the negative charge is briefly lost - maybe a signal to tell other bbees not to visit? Other work by Bristol University has indicated that synthetic fertilisers and pesticide can interfere with a flower’s electric charge for some time after spraying, and that this can modify the foraging of bumblebees. "Black bees" The black bee, Apis mellifera mellifera, faces a number of threats like the domestic honey bee.  It is also known as the European Dark Bee or the Black German Bee. It has been present since the retreat of the last Ice Age, but its distribution has become restricted as a result of habitat loss, parasitism by Varroa mites and viruses. The black bee can be distinguished from other honey bees by its stocky body and sparse abdominal hair (which is brown), and overall dark coloration - so they appear black or dark brown. Recent research (using DNA analysis) has shown that black honeybees can be found in many locations in Ireland and are not extinct, as previously suggested  Black bees are noted for their longevity and hardiness (ability to cope with winter temperatures); it is possible that if winters become shorter / milder that this change may not favour black bees. Weird weeds? It seems that our gardens may be home to ‘new’ or unusual species of plants.   The Royal Horticultural Society would like gardeners to report on interesting ‘weeds’ that might find as they could be rare plants or plants growing in unusual places / areas.  You are asked to take photographs of anything that you find interesting, and upload the images to iNaturalist. Reporting on unusual plants is not the only thing that the RHS is interested in. There are other garden projects that one can contribute to, for example, reporting sightings of garden pests such as the berberis sawfly, cellar slug, hemerocallis gall midge, lily beetle, rosemary beetle and spittlebug. Mycorrhizal networks. A common mycorrhizal network (CMN) is when fungal hyphae connect the roots of many plants (either of the same or different species) below ground.  They have attracted considerable attention in recent times (woodland wide webs), with claims, for example, that resources are transferred through CMNs to increase seedling performance and mature trees send resources / defence signals to offspring etc.  However, a recent report in Nature has suggested that there is a ‘bias’ towards citing the positive effects of CMNs and that, to date, knowledge of common mycorrhizal networks is limited.    

No match for nonpareil ? Many varieties of apples have been around for centuries.  For example, the nonpareil which was bred (in France) back in 1696, the Egremonet russet much admired for its flavour and appearance dates from Victorian times. The  Cox's Orange Pippin is a cultivar first grown at Colnbrook in Buckinghamshire by Richard Cox.   By end the of the C19th, the Cox’s pippin was one of the most popular apples. However, there is a concern for these heritage apples in our changing climate.  In recent years, we have experienced warmer and wetter winters.  Such winters do not offer enough chilling hours for these trees.  Many trees need a period of cold in the winter months, where the temperatures are below 6oC but above freezing.  About 1000 chilling hours are needed for apples such as the nonpareil.  However, winters are present are offering approximately 600 chilling hours. Gala apple trees (developed in New Zealand) need only 600 chilling hours but it might be that they will not respond well to the wet winters we (currently) experience.  Some feel that they do not offer the complex flavours of ‘classic apples’.   Kew Gardens has now planted a varied selection of apple trees One third are heritage apple trees One third are ‘new’ varieties needing fewer chilling hours One third are varieties from countries warmer than the UK Over the coming years, the trees will be monitored to see which ‘do best’ in terms of cropping in London’s warming temperatures. The apple-growing industry in the UK is under considerable strain, with many growers unable to afford replanting this year.  Growers ‘refresh’ their orchards regularly, replacing older trees with new ones, but now many cannot afford to do this.   The sector is struggling with  a shortage of workers - made worse since the UK's exit from the European Union  high energy costs low returns from the supermarkets that buy their produce The option to ‘buy British’ may become a much rarer option.   Further details here Recovery after forest fires. Bacteria and fungi are the first to start rebuilding from the charred remains of burnt forest and woodland.  The number and variety of microbes falls dramatically after a fire.  Then, there was a microbial succession in the burned soil, that is, the number and types of bacteria and fungi changed quite quickly, with fast growing types able to advantage of the reduced competition for resources.  The situation is not dissimilar to what happens to our gut microbiome when we have to take antibiotics.  Antibiotics ‘knock out’ many of the useful bacteria in our gut, but gradually the microbiome is re-established.   Reporting on weeds. It seems that our gardens may be home to ‘new’ or unusual species of plants.   The Royal Horticultural Society would like gardeners to report on interesting ‘weeds’ that might find as they could be rare plants or plants growing in unusual places / areas.  You are asked to take photographs of anything that you find interesting and upload the images to iNaturalist. Reporting on unusual plants is not the only thing that the RHS is interested in. There are other garden projects that one can contribute to, for example, reporting sightings of garden pests such as the berberis sawfly, cellar slug, hemerocallis gall midge, lily beetle, rosemary beetle and spittlebug.

Back to one’s roots? Some of the effects of agriculture are very obvious, such as the vast areas of land now covered by monocultures of wheat or oil seed rape.  The expansion of mechanised agriculture has resulted in significant reductions in biodiversity, for example, through the loss of hedgerows and ponds (see the post on ghost ponds in Norfolk).  However, agriculture has others effects that are not quite so obvious.   Soils are ‘filled’ with roots, and roots help engineer landscapes.  They help: break up bedrock, improve permeability of the soil to water  stabilise the soil,  store carbon transport water and minerals to the plants.   They have been doing this for millions of years since the colonisation of land by plants. Now, research by scientists in the United States, has shown that the roots of agricultural crops are significantly less deep than those of  the  natural vegetation in an area.  Indeed, the root depth may be shallower by some 60 cm, compared to the natural root systems of an area.  If the soil is less root material then there is  decreased carbon storage,  reduced nutrient recycling and  possibly reduced soil stability.   Whilst there are some areas where “woody encroachment” is occurring (for example, shrubland taking over in some grasslands and forest advance into regions of tundra so root depth is increasing) -  the onward march of agriculture is dominant. Full details of this analysis / research : https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022EF002897 Shrinking in winter Recent research has shown that some small mammals (like moles and shrews) shrink in size during periods of cold temperature.   This shrinking is thought to be a response to cold temperature rather than lack of resources.   This change in form has been known for some 70 years and is referred to as Dehnel’s phenomenon.  Professor Dehnel observed this change in form in shrews [in Poland in 1949].  However, shrews have a short lifespan so an extended studied of this phenomenon with these animals was not / is not possible.   Recent studies by German researchers have focused on moles, who can survive harsh winters by becoming  smaller.  It is thought that this reduction in size enables energy savings.  According to Dr Dina Dechmann this reduction in size comes at a cost, as the animals’ cognitive behaviour is affected. Further information here : https://royalsocietypublishing.org/doi/10.1098/rsos.220652 Farming and sustainability With the expansion of farming, less and less of the land is available for our native plants and animals,  Hedgerows and ponds have been lost / removed, natural habitats have been reduced. The government has produced new guidance on environmental land management schemes (ELMs).  That is subsidies that will be paid to farmers if they help promote and protect nature and improve the environment (e.g. using less insecticide and reducing pollution). There would be payment /subsidies for some 280 measures, for example : Creating fenland from lowland peat Maintaining sphagnum moss Creating land that could produce organic fruit Establishing a skylark plot Adding organic matter to the soil Creating green cover over winter (on 70% of the land) Welcome as these measures might be, there is criticism that they favour big arable farmers and do not really help those working on more marginal land (such as upland and moorland regions). Further information available here. Trees - From Root to Leaf For those who like their trees, here is a new book about them.  Written by Paul Smith -who was head of the Millennium Seed Bank of the Royal Botanic Garden, Kew.  Not read or seen a copy but the Sunday Times comment "'Stunningly illustrated and detailed ... a celebration of all things arboreal, from the seeds, leaves, flowers and fruit to the diversity of trees and how they have influenced art, culture and science' suggests that it might interest.  See "https://press.uchicago.edu/ucp/books/book/chicago/T/bo186012850.html"  

Ancient Trees A recent report has emphasised the importance of protecting and preserving ancient trees.  Ancient (veteran) oaks can live in excess of a thousand years, as can Yews.  The Bristlecones of California and Nevada may live for some five thousand years ! Such trees represent a massive carbon store; the carbon dioxide from the atmosphere being locked away for a millennium or five!  Not only are such trees a significant carbon store but they also offer a home or food for many other species - fungi, epiphytes such lichens & mosses, plus larval and adult stages of insects, birds and mammals.  As such they localised centres of diversity that contribute to ecosystem stability.  Not only are these trees ‘hotspots’ for species diversity but they are also centres of mycorrhizal activity and connectivity.  Mycorrhizae represent the symbiosis between fungi and plant. Plants ‘register’ wounding. When we are hurt, our nerves register the pain through the movement of sodium and potassium ions along the nerves.  When a plant is wounded, calcium ions are known to move in response, travelling from cell to cell, and leaf to leaf.  However, it is now known (through research at the John Innes Centre in Norwich) that this is not the first response of the plant to physical injury.  When cells are wounded they release glutamate, a form of glutamic acid.  This travels along the cell was and activates channels in the cell membranes that allow the movement of the calcium ions.   A bumblebee pathogen. One of parasites of bumblebees is Crithidia bombi.  It is a protozoan (single celled animal) that reproduces in the gut of the bumble bee. When infected with this parasite the foraging behaviour of the bee is impaired, as is its ability to learn.   A colony will suffer from increased worker mortality.  Now research has shown that floral structure may influence the transmission of this parasite from bee to bee.  The length and shape of the petals seems to be a critical factor.  If the bees ‘crawls’ in a ‘tube’ of petals, then it may leave behind some faeces.  If the bee is infected with the parasite, then it will be present in the faeces.  If the flower is then listed by another bee then it runs the risk of coming in contact with and being infected with the parasite.  Plants that have flowers with shorter petals / corollas are less likely to have faeces deposited within them, and therefore less likely to pass on the parasite to the visiting bumblebees.

Moss puts a brake on peak flow and flooding. “Moors for the future” have been working in the Peak District to investigate the run off of water after rain.  Often after a storm, rain water will run off a hillside unimpeded so that communities downstream in valleys are vulnerable to flooding.  Moors for a future have been planting upland areas (on Kinder Scout) with Sphagnum moss.  They have planted some 50,000 plants of the moss.  Prior to the planting of the moss, the surface might be bare, and rainwater would run straight off.  It was found that the moss dramatically slowed the run off of water, and the volume of water discharged from the hillside, preventing rivers from becoming inundated.  Each moss plant can hold up to twenty times its own weight of water.  The sphagnum moss also protects the underlying peat, so that new layers of material can accumulate - allowing for carbon sequestration. Help from vegetables ? More and more bacteria are now resistant to many types of antibiotics, consequently it is increasingly difficult to treat certain types of bacterial infection / disease.  In some cases, this is due to the production of a biofilm.  Bacteria grow on many surfaces within our bodies and as they grow and multiply they may encase themselves in a matrix of extra-cellular material that they produce ( as seen in Pseudomonas sp). Research workers at the Ben Gurion University have found that certain compounds from cruciferous vegetables, such as broccoli, can break down these bacterial films. Cruciferous vegetables include Cabbages, Cauliflower, Brussels sprouts, Kale, Radish, Kohlrabi and Mustard. The chemical DIM (3,3 diindolylmethane) was able to disrupt the biofilm.  When introduced to an infected, wound, it was found to speed up the healing process. It is hoped that further work will lead to a commercially viable product for the treatment of certain infections. (Thanks to Ulleo on Pixabay for adjacent image). ‘Help Signals’ from oil seed rape. Oilseed rape (or rapeseed, Brassica napus) is a major crop in many parts of the country.  It provides an oil and is also contributes to animal feedstuffs and biofuels.  Great swathes of the country turn yellow when the plant is in flower during the summer months.  These monocultures are ideal for the animals that feed on the plants, these range from insects, to nematodes, slugs and wood pigeons   One particular pest of oil seed rape is the Common Pollen Beetle (Brassicogethes aeneus).  The female beetles lay eggs in the flower buds of and the larvae develop within the flowers.  Both adults and larvae feed on the pollen and nectar in the flowers. Plants have limited means of fighting attackers.  They may construct structural defences, as discussed in the woodlands blog, or they may use chemical defences.  When bitten by a marauding herbivore some plants emit volatile organic compounds (VOC’s).  As the pollen beetles feed, the rapeseed releases VOCs which attract the attention of other insect - notably those that will lay their eggs into the larvae of the pollen beetles. These insects are usually from the same family as bees, wasps and ants - the Hymenoptera (insects with membranous wings and a ‘narrow waist’.   The pollen beetle larvae are then ‘eaten’ from the inside by the developing parasitoid larva.  This effectively constitutes a form of biological control.  Interestingly, the pollen beetles preferred to lay eggs into rapeseed plants plants growing with high levels of N fertilisation, whereas their parasitoids favoured more moderate levels of N fertilization.  This work was undertaken  at the Estonian University of Life Sciences. Finding the flowers. Research at the University of Exeter has shown that bees can distinguish between various flowers through a combination of colour and pattern.  This selectivity is achieved despite the ‘acuity’ of a bee’s vision being quite low (about a 100 times lower than ours) - this means they can only see the pattern of a flower when they are quite close ( a matter of centimetres).  The researchers analysed a large amount of data on plants and visiting bee behaviour, and experiments involving artificial shapes and colours.  One particular finding was the importance of the contrast between the outside of the flower and the plant’s foliage.  This seemed to help bees quickly find their way to the flowers.

Shade and stress. Shade (low light intensity) causes plants to elongate, reach up to the light to ‘outgrow’ the competition.  Such ‘elongated plants’ are said to exhibit etiolation.  However, there is a point when this strategy is counterproductive.  The plant simply cannot outgrow its taller neighbours, it is wasting resources and becoming weaker.  So plants in deep shade do not generally use this strategy.  Deep shade is detected by the phytochrome pigment system and ‘relayed' onto the plant’s circadian clock, the internal ‘daily time piece’.  This internal clock has various components and particular genes, some of which have an additional role in suppressing stem elongation (that would normally occur when shaded). Welsh woodlands and insect pollinators. A recent study across many different sites in Wales has revealed the habitats favoured by pollinators such as bees, overflies and butterflies.  The research found twice as many insects in broad leaved woodlands as compared to grassland areas.  They also found that farmlands without hedgerows had significantly fewer insects.  Both hedgerows and woodlands include trees such as oak and maple, which offer varied niches for pollinators.  They provide food (leaves) for larval stages, pollen and nectar for adults, plus egg laying sites and shelter. In Wales, there are plentiful grassland areas (mainly due to farming) with woodland only contributing 15% of land cover.  However, the Welsh Government aims to plant 180,000 hectares of new woodland by 2050.  New woodland will not only contribute to tackling climate change (through carbon sequestration) but will also do much to promote insect biodiversity. Sludge as fertiliser Sewage sludge is commonly spread across farmland as a form of fertiliser (throughout Europe).  Sewage sludge is the residual, semi-solid material that is the ‘by-product’ of sewage treatment of industrial and / or domestic wastewater. Sometimes, referred to as biosolids. It is a sustainable / renewable source of nutrients and reduces material going to landfill or incineration. The use of sludge has attracted attention as it can contain: Breakdown products of various medical / pharmaceutical that have been excreted / eliminated from us and / or animals, such as hormones, antibiotics, various drugs Heavy metals such as lead, cadmium, arsenic  Industrial chemicals / breakdown products PCB’s, dioxin Now, research at Cardiff University has shown that micro plastics in sludge are a problem; these are plastic particles less than 5 mm in size. It estimates that between 31,000 and 42,000 tonnes of micro-plastics are applied to European soils each year.  They are a threat to wildlife as they are easily ingested and can carry / contain toxic chemicals and may pass along the food chain.  The UK was shown to potentially have the highest level of microplastics in its soils, followed by Spain, Portugal and Germany.  

Mites and bees. Varroa destructor also known as the Varroa mite is a small, external parasite of the honey bee : Apis mellifera. It is a mite. Mites are small members of the arachnids (8 legged arthropods).  The mite(s) attaches to the body of the bee and feeds upon its fat bodies; this weakens the bee. The mite also feeds on bee larvae. Not only that but the mite can act as a vector (‘distributor’) for five different viruses that also weaken the bees.  The varroa mite originally was to be found in Asia, and was parasitic on the Asian honeybee, Apis cerana.  Sadly, it has now spread to many countries and is responsible for significant infestations of European honeybee hives.  Over time, the mites have become increasingly resistant to chemical treatments. Now a program / study by the Universities of Exeter and Louisiana has been selectively breeding bees that identify and remove mites from their colonies [ie. showing hygienic behaviours].  They do this by removing infected larvae from the colony.  This is sometimes referred to as varroa sensitive hygiene.  Such colonies showed significant reduction in mite numbers and were more than twice as likely to survive winter as compared the ‘standard’ honey bees. The colonies also had reduced levels of three honey bee viruses The study looked at bee colonies across three American states, including California.  In the States, beekeepers move thousands of bee colonies to provide pollination services for many different fruit crops (e.g. almonds) in the Spring, thus winter survival of the colonies is vital. Historic rainfall records. was launched in March 2020 (during the 'first stay at home' / lockdown).  Members of the public were asked to help record digitally the information on pre-1960 weather sheets.  The Met Office archives had some 65000 sheets that contained the ‘scribbled records’ of thousands of weather stations/ weather recorders across the country.    Many of these sheets were the records of amateurs dating back decades, many before the foundation of the Met Office in 1854. One such 'recorder' was Lady Bayning of Norfolk, she was an early rainfall observer who took readings from 1835 to 1887.  Deciphering the idiosyncratic handwriting could not be done by character recognition software. However, the volunteers rose to the challenge and the task was completed in some 16 days. As a result, now the Met office has: Rainfall readings stretching back to 1836 Data from an increased number of rain guages  Identified the driest year on record - 1855 Identified the driest month on record February 1932 Identified the wettest month on record October 1903 Note : [The Met Office was founded by Robert Fitzroy, the captain of HMS Beagle, that carried Charles Darwin on his epic voyage around the globe. Fitzroy essentially established the science of weather forecasting] Trees on the move ? We know that trees can ‘move’.   They did so at the end of the last Ice Age (some 12,000 years ago).  As the glaciers retreated so trees started to return to the newly exposed soils as the temperature warmed.  The discovery of the remains of acorns in archaeological digs, and analyses of fossil pollen records indicates that even oaks colonised areas of the UK at the rate of nearly a kilometre a year.   Similarly, Norwegian Spruce colonised areas around the Baltic Sea and the boreal forests grew and expanded - long before humans arrived there.   Now we have warming temperatures as we have moved into the Anthropocene.  In order to survive changes conditions, plants, like us, have to move. So, like after the ice Age, plants and trees are on the move.  Scientists in California have calculated that as a result of global temperature changes, plants need to move northwards (or upwards) at the rate of 400+ metres a year.  In the eastern parts of the United States, it has been estimated that trees were shifted north and westward at a rate of 10 / 15 km per decade.  The conifers going north. Whilst oaks and birches going west.  In Scandinavia, which has experienced significant aspects of global warming, birch saplings are now found higher up mountains, gaining 500 metres in elevation within two decades.  Pines, spruces and willows are also growing at higher altitudes than previously.  Similar colonisations of  hillsides and ‘bare valleys” are seen in Alaska of alder, willow and dwarf birch. Further information here [caption id="attachment_38737" align="aligncenter" width="700"] Busy bee[/caption]