It is depressing to pick up a paper or turn on the news to be met with a catalogue of distressing and difficult stories.  There is also the overarching problem of global warning and climate change.  Only recently, there have been reports of flooding in Sydney after torrential rain, fires are springing up again in Colorado and other States, and India experienced a heat wave (combined with a drought), with some cities experiencing temperatures of 40o+C.  This has resulted in the deaths of individuals, and as the heat wave occurred in the final weeks of the wheat growing season it has killed many crops before harvest.  In Balochistan, the peach and apple harvest has been severely impacted. Here in the UK, there are a number of problems, indeed we have been described as “one of the most nature-depleted countries in the world”.  We have lost plant and animal species, such losses could lead us into an ‘ecological recession’. This occurs when ecosystems systems lack the diversity needed to function well. Much of the damage to (or loss of) our ecosystems is associated with the industrial revolution followed by the  intensification of mechanised farming. The 1950’s and 1960’s witnessed the loss of vast tracts of hedges and the removal of small copses to increase the area for farming / food production, and allow the use of heavy duty mechanised machinery.  There was also the extension of road networks - motorways etc. and urban sprawl /development.  Though woodlands and forests were being eroded long before the industrial revolution; woodland, forest and pasture covered much more of the land than now. There were areas of ‘wilderness’ that were home to animals and plants that have long since gone or are now very rare - ranging from wolves, bears, to beavers and red squirrels. Whilst woodlands were and are havens for many plant and animal species, meadows and pastures have suffered too.  The PlantLife charity has suggested that the UK has lost some 97% of its wildflower meadows during the course of the last century and what remains could be under threat. Lowland meadows are rich sources of biodiversity, both plant and animal, they also store carbon in the soil and ‘knit’ the soil together, so that it is not subject to erosion. [caption id="attachment_38489" align="aligncenter" width="700"] A meadow, partly mown and partly 'wild'.[/caption] Many species are dependent on these habitats, but with the expansion of agriculture and construction of motorways - the landscape has become fragmented and many species cannot across the formidable barriers.  The Scottish primrose is now only to be found on the north coast of Scotland and Orkney, and some orchids are described ‘as just hanging on’.  Species like the common blue butterfly is reliant of bird’s foot trefoil, Greater Bird’s-foot-trefoil, Black Medick and white clover for food for its caterpillars.  The great yellow bumblebee is sadly now one of the rarest British bumblebees. It is limited to flower-rich areas in the Orkneys, Caithness and Sutherland. It is particularly associated with red clover. It is a large species, and was once widespread across the U.K. Creating space and opportunities for wild flowers has been PlantLife's foremost objective from “No mow May”, “Save nature on our roadside” (see the woodland blog here and here) ’Fight for sites” all of which aim to increase the number of sites for wild flowers and their pollinators to flourish.  The Scottish Government has been helping establish wildflower meadows at some of its national nature reserves - notably St Cyrus, Flanders Moss and Forvie, and they are working with PlantLife to create an action plan for Scotland’s grassland.  It is keen for farmers to be involved, offering areas of wild flowers on their farms.  By increasing the areas in which wild flowers (and their associated insects) can flourish, the connectivity can be restored (at least in part).  The creation of biological corridors allows plants and animals to move, which is particularly important in these times of climate change.  

The European hornet (Vespa crabo) is an eusocial insect.  That is to say, hornets live in colonies, with some 200 / 400 individuals in each colony.  A colony is founded by a fertilised queen, who emerges from hibernation in spring. Hornet queens are the sole survivors of an old colony after  a UK winter and they emerge as the weather finally starts to warm in early spring.  They then seek a warm, dry place to start nest construction. Once a nest location has been secured, they lay eggs that hatch into larvae.  The larvae are fed on protein-rich food (chewed up insects) and then they pupate; undergoing metamorphosis [a complete reorganisation of the body].  An adult hornet worker then emerges from the pupa some two weeks later.   These are ‘sterile’ female workers, who take over nest building and collecting food for the next set of developing larvae.   The developing colony lives within the papery nest its a (a bit like papier mâché), adding to the structure as the colony grows.  Twigs, bark and other plant material is broken up, chewed and shaped to form the nest. This material is glued together by their saliva.  Larvae that hatch in the summer are either fertile queens or males.  The males (drones) do not contribute to nest building, food foraging etc.  But in autumn, the males (drones) and the new queens leave the nest to mate.  The fertilised queens hibernate over winter, emerging in spring to start a new nest.  The ‘sterile workers’ and the male hornets die with the onset of winter. In other colonies of social insects, like honeybees, female workers don’t reproduce due to the pheromones that are released by the Queen. This was thought to be the case for European hornets but instead worker hornets enforce ‘sterility’ by physically destroying any worker-laid eggs or the workers laying them ! The food of a hornet is surprisingly varied. They can hunt and capture a wide variety of invertebrate prey (beetles, wasps, moths, dragonflies, robber flies - they may even prey on honey bees).  In many ways, hornets are useful in that they predate on a number of  garden and agricultural pests. Much of this prey is then chewed up to feed the growing larvae.  In return for this material, the larvae willingly ‘exude’ for the adults  a sugary liquid for them to feed on. Adults can also be found feeding on sugar-rich sources such as tree sap, nectar, and ripe fruit. They are more likely to ‘scavenge’ food at the end of summer into autumn rather than hunt.  The head of the insect has dark, prominent eyes, its wings are a reddish-orange, whilst the abdomen is striped with yellow and brown.  Hairs are present on both thorax and abdomen but they are not ‘hairy’ like bumblebees.  The colour of hornets can vary and a number of regional colour forms are known across Europe.  Worker hornets are about 25 mm in length, whilst queens may be up to 35 mm., so significantly bigger than wasps.  Partly because of its colour and size, a hornet can be mistaken for the Asian Giant Hornet (previously reported on in the woodlands blog).  However, a recent report indicates that the european hornet can attack and kill the Asian Hornet, by biting its head off.  Asian hornets are a considerable worry as they attack and kill  honey bees, plus their venom can induce life threatening anaphylactic shock. Breaking news : Asian hornets seen in Essex.   https://www.independent.co.uk/climate-change/news/asian-hornet-uk-bees-insects-b2177217.html In the past, the European hornet was rarely seen in the UK, being largely confined to areas of central southern England, but it has expanded in range in more recent times and is to be found across the South East and even in some more northerly locations.  Female hornets (but not males) have a stinger.  The venom within the stinger contains mixture of various neurotransmitters (serotonin, dopamine, histamine) as well as a concoction of enzymes.  Best avoided !  

The decline in insects numbers, especially pollinators is a cause for concern.  Insect numbers have fallen as natural ecosystems have been lost or disrupted by the expansion of farming and urbanisation, plus the increased use of pesticides and herbicides. The loss of insects not only affects the pollination of many commercially important plants, but also affects the animals and birds that feed upon insects.  So, there are knock on effects throughout food chains and ecosystems. Plantlife has launched a number of initiatives, such as  No Mow May,  Transforming Road Verges Saving Meadows to help offset the decline in insect numbers.  Now work done in Professor Goulson’s laboratory at Sussex Univeristy by Janine Griffiths-Lee (a PhD student) suggests another approach to increasing insect / pollinator levels in urban settings.  Her research has demonstrated that creating a small patch of wild flowers in gardens can go some way to address this fall in insects numbers.    She and colleagues managed to enlist the help of some 150 volunteers distributed across the UK (many were members of the Buzz Club*). Each volunteer set aside a wild flower area  - a mini-meadow (two metres by 2 metres).  Some  of the volunteers then sowed the mini-meadow area with a commercial seed mix of wild flowers, others sowed a seed mix designed / thought to be ‘beneficial to pollinators’. A third group did not receive wild flowers seeds but were asked to set insect traps and record insects in their gardens in the same way as the two ‘wild flower seed groups’. The results were interesting and revealing. The mini-meadows proved to be resource-rich habitats, with an increased numbers of wild bees, more bumblebees, solitary bees and also wasps (when compared to the control group with no wild flower seed sowing).  There were differences in the insect populations for the two groups of seed.  The commercial mix attracted more solitary bees and bumblebees, whereas the ‘designer mix’ of seeds attracted more solitary wasps.  There was no difference in the number of hoverflies that visited the two types of wild flower rich mini-meadows.  Solitary wasps, whilst not pollinators, are important in that they prey on a number of insect pests of fruit and vegetables. Clearly, the planting of small areas in gardens with wild flowers could do much to encourage the numbers and variety of insects / pollinators visiting (or possibly help control the damage done by insects pests).   * The Buzz club is a citizen science initiative.  The UK has a tradition of using the enthusiasm of volunteers to collect data for ecology research.  The Buzz Club projects are focused on gardens - see here.  Membership of the Club is free and the research projects are generally involve no cost.  You might be asked to supply simple equipment or to cover the cost of sending samples back to the club based at Sussex University. Should you sign up then you will receive : A ‘thank you’ email from the team! Information direct to your inbox of new projects being planned. A newsletter about what your data is telling us.  Professor Goulson has previously written a blog about bumblebees for woodlands.co.uk

The UK has experienced some of the highest temperatures ever recorded in recent weeks, and in some parts of the country this has coincided with very low levels of rainfall.  It was the driest July on record for East Anglia, southeast and southern England, according to provisional statistics from the Met Office.  July was also the first time the UK exceeded temperatures of 40°C: on 19 July during an intense heatwave.   These conditions are not without their effects on wildlife.  Whilst warmth can accelerate plant growth and development, and also speed up insect life cycles, but the recent very high temperatures have significant effects, for example:  Drying of the soil As the soil dries, so earthworms burrow down deeper.  Insects, woodlice, spiders, etc avoid the surface of soil, hiding in litter so birds like song thrushes, robins and blackbirds struggle to find something to eat. Consequently, they are less likely to produce a second brood of chicks. This scarcity of invertebrates also affects ground feeding mammals, like hedgehogs (and badgers in more rural locations). Wetland areas dry out; for example grazing pasture that floods in winter - like the Ouse Washes.  This makes it difficult for birds to find food. Lack of water for plant growth Reduced rainfall and high rates of evaporation from the soil (and plants) mean that there is considerably less water available for plant growth.  The growth of leaves is reduced so that there is less material for caterpillars and other insects to eat.  With fewer leaves , there are also reduced surfaces for butterflies and other insects to lay eggs. High temperatures High temperatures and lack of water can affect many animals (including us). Rivers are running at very low levels and some have more or less disappeared.  DEFRA’s latest assessment of principal salmon rivers, such as the River Test shows that 74% of rivers in England are now ‘at risk’. The Environment Agency has noted the flow rate in the Waveney as 'exceptionally low', while other rivers in East Anglia like the Great Ouse  the  Yare, and the Little Ouse are described  as 'notably low'. The young of birds like swallows and swifts are at risk of fatal overheating (the young and old of various species are often more susceptible to heat stress).  Bumblebees cannot forage at high temperatures. Their bodies are covered with ‘hairy coats’ so they can fly when it is cool; but these become a burden in hot spells.High temperatures also shorten flowering time, and hence the availability of pollen and nectar for pollinators (bees, bumblebees, overflies, butterflies). Wild fires. [caption id="attachment_35352" align="aligncenter" width="650"] Woodland recovering from a fire[/caption] High temperatures increase the risk of wild fires, especially on moorland and heathland.  These fires can spread quickly and over wide areas. Young chicks (e.g. Dartford Warblers), eggs, snakes, lizards, small mammals, dragonflies and butterflies are lost.  Accumulated nutrients and stored carbon are lost from the ecosystems. The site of Springwatch Wild Ken Hill in coastal Norfolk suffered an intense fire during the recent hot spell.  The area is home to turtle doves, the grasshopper warbler and other rare birds.   It is hoped that most escaped but mammals, reptiles and amphibians, late-nesting and juvenile birds may not have fared well.   Grassland and woodland fires have also been reported at various sites across the country.  The UK is not alone in facing these problems, Spain, Italy, Portugal, Greece, France and Germany have all lost many thousands of hectares to wildfires. [caption id="attachment_38699" align="aligncenter" width="700"] what was once was grass .....[/caption]  

It may be that a dead hedge is just that, your once carefully manicured box hedge which has now been ravished by the box moth.  However, in terms of managing your woodland, a dead hedge may have a different meaning. Here, a dead hedge may be a barrier to an area of new planting, it may be a way to ‘persuade’ people to keep to a footpath, or keep away from a pond / stream.   The dead hedge will be made from the bits and pieces that have be culled in clearing and thinning operations within the wood, material that foresters sometimes refer to as ‘lop and top’ and tree surgeons call ‘arisings. It can also include material cut from brambles and climbers such as ivy, honeysuckle and Old Man’s Beard (Clematis). Using natural materials to create barriers (and indeed) a habitat in a woodland is a way of using ‘waste’ in an ecologically sound way.  It saves having to remove trimmings from the site and offers opportunities to ‘top up’ the hedge if desired.  Obviously diseased materials should not be used.   Creating a dead hedge from clippings and trimmings is a way of using natural materials, rather than plastic & other materials that do not readily decompose.  A dead hedge will be an effective barrier for a period of time but it will break down sooner or later as bacteria and fungi break down the woody remains (lignin and cellulose).  The disappearance of the hedge will take time as the branches twigs etc are largely off the ground, so relatively dry and decomposition is facilitated by warmth and wetness. After its initial ‘construction’, the hedge will become part of the woodland, it will be colonised by some plants and it will offer shelter, nesting sites for birds and small mammals, and a ‘home’ to many different invertebrates, such as woodlice, beetles, even certain species of bumblebees.  As the hedge deteriorates, that is, decomposes, so the soil will gain in humus and fertility as the nutrients from the decaying wood etc are released through the detrital food chains.   Another way of using / recycling bits from pruning, clearing etc is by Hugelkultur.   Hugel beds are basically raised beds with a difference - they are filled with rotting wood and other biomass.  They are packed with organic material, nutrients and air pockets. Such beds can be an effective way of creating a productive area for growing fruits and vegetables in your woodland.  There is a woodlands blog about hugelkultur here. Large chunks of wood e.g. sawn up tree trunks can be stacked up in small piles and will over time make an excellent home for many invertebrates but especially xylophagous (wood eating) insects, for example,  saproxylic beetles.  These are beetles that live / eat in dead wood.  In the UK, some 600+ beetle species (from 53 different) families are associated with deadwood. Some feed on the deadwood itself (often with the aid of symbiotic bacteria in their gut), others feed on the fungi that are gradually ‘dissolving’ the wood.  Ants and wasps sometimes make their nests in dead wood.   Using wood to increase the organic content of the soil is good in terms of  carbon sequestration,  improving soil fertility,  water conservation and  productivity.  

The pollen forecast across much of SE England this week is very high, according to the Met Office.  Pollen is the ‘powdery material’ produced by higher plants (angiosperms and gymnosperms). It is made up of individual pollen grains, which are produced in the anthers⚘.  When these anthers split open, the pollen grains are released and move by means of the wind or insects to the female reproductive structures (style and stigma in flowering plants, or the female cones in conifers etc).  If a pollen grain lands on a compatible stigma or female cone*, it germinates - producing a pollen tube that transfers the male gamete to an ovule within the ovary. Individual pollen grains are small enough to require magnification to see any detail.  A pollen grain has two layers : The outer layer of the pollen grain is called the exine and is made of a material called sporopollenin. This is a polymer (long chain molecule) made up of various organic molecules; it does not degrade easily. In fact, it can exist in the soil and sediments for hundreds if not thousands of years. The persistence of this outer wall of pollen grains enables scientists to identify species that were present in various sediments formed thousands of years ago. Under the electron microscope the exine has a sculptured, almost ‘sci fi’ appearance - with ridges, groves, spikes, and distinctive patterns across its surface - which are unique to each species.  The inner layer of the pollen grain is the intine. It is made from  pectin and cellulose; it has a role in the germination of the pollen tube. Wind dispersal of pollen is referred to as anemomophily.  Anemophilous plants, like the grasses, generally produce large quantities of lightweight pollen. This is because wind dispersal is random and the likelihood of any one pollen grain landing on another compatible flower is remote, but the probability is increased by there being large amounts of pollen. The individual flowers of anemophilous plants are often small, inconspicuous but may collected together into significant structures (think pampas grass).  The pollen of insect pollinated flowers is relatively heavy and sticky (often protein-rich). The hind limbs of bees and bumblebees are modified for the collection of pollen - the pollen baskets or corbiculae.  Each corbicula is a cavity surrounded by a fringe of hairs into which the bee places the pollen.  Apart from this collection of pollen, pollen may be seen sticking to the hairs / the surface of a visiting insect. [caption id="attachment_24330" align="aligncenter" width="600"] Bumblebee dusted with pollen[/caption] [caption id="attachment_38370" align="alignleft" width="300"] Grass inflorescence - with protruding stamens[/caption]   Whilst pollen is generally harmless, there are some pollens which really ‘get up your nose’ - specifically Tree pollen, from trees such as Birch and Lime Grass pollen, from ryegrass and timothy “Weed’ pollen, from ragweed, mugwort, plantain, fat hen These various pollens can cause allergic reactions when inhaled and the body’s defences are alerted.  The defence reactions may include, sneezing, a runny nose, watery / inflamed eyes.  Tree pollen tends to peak earlier in the year than grass pollen.  Grass pollen is probably the worst offender when it comes to ‘hay fever’ / allergic rhinitis.  The pollen calendar (courtesy of Kleenex) gives a seasonal guide to pollen by month and by area.   ⚘ Anthers are the pollen producing tubes / sacs at the end of the filaments.  Anther plus filament = stamen. * Conifer pollen grains often have air ‘bladders’ which help with the ‘bouyancy’ of the grains so they are easily dispersed in the wind.]  [caption id="attachment_38360" align="aligncenter" width="700"] stamens that have released their pollen[/caption]   Pollen grain image, thanks to Open ClipArt on Pixabay.

It would seem that pollinators have ‘favourite plants’.  Research centred on the National Botanic Garden of Wales has looked in some detail at the foraging habits of bees, bumblebees, hover flies and solitary bees - our most important pollinators. Dr Abigail Lowe identified the plants that the insects were visiting by analysing the DNA from pollen grains on their bodies (a process known as DNA barcoding). It is clear that the ‘preferences’ of the insects change with the seasons and indeed the availability of particular flowers.  In Spring, nearly all the pollinators frequent buttercups, lesser celandines and dandelions (all brightly coloured yellow flowers).  Come the summer, honey bees and bumblebees tend to favour thistles, knapweeds and brambles, whilst hover flies may be seen on hogweeds and angelica plus thistles and knapweeds.  In autumn, the bumblebees can be see visiting asters (Daisy family flowers) and brambles. Full details of her work can be found here : https://botanicgarden.wales/press/plants-for-pollinators-new-dna-research-reveals-fascinating-insights-into-the-plants-used-by-bees-and-hoverflies/ There are also suggestions on how to help pollinators in your garden, such as encourage buttercups and dandelions by reducing mowing (in the Spring) plant late flowering daisy type flowers encourage some bramble (you might get some blackberries, in return) reduce the use of chemicals (especially pesticides and herbicides) hoverflies can be encouraged by damp, wet areas and rotting wood and these suggestions would also work in a woodland.   [caption id="attachment_38320" align="aligncenter" width="700"] Marmalade hover fly[/caption]

In recent decades, signs of Spring have occurred earlier and earlier, indeed the early flowering of crocuses and daffodils in our gardens is one such sign. Now a detailed analysis of such ‘signs’ has been undertaken by using the information held in Nature’s Calendar.  This is an enormous database * of records of seasonal changes; it has records of some 400+ species of plants, from trees, to shrubs and herbs. Nature’s Calendar includes records from organisations like the Royal Meteorological Society, plus those of scientists, naturalists and gardeners. Recording when things happen (such as when horse chestnut and ash trees come into leaf, or when the first swifts or bumblebees are seen) is known as phenology. These timings vary from year to year.  Phenology is not a new discipline. One of the first phenologists was Robert Marsham, who recorded ‘indications of spring’ starting back in 1736. He catalogued some 27 different natural events on his family’s estate in Norfolk.  In 1875,  the Royal Meteorological Society set up a national recorder network.  Nature’s Calendar includes thousands of these historical observations and enables scientists to look for trends and see if they correlate with changes in temperature, rainfall, weather phenomena. The research team from Cambridge University looked at FFDs - first flowering dates and temperature records. They found a difference in flowering dates from the 1750s and the most recent years of almost a month.  Professor Ulf Büntgen has said that rising global temperature has brought Spring forward by several weeks.   This raises concerns. For example, if a plant grows and comes into flower earlier in the year what happens to insects that are dependent upon it? For example, some bees collect from only one species of plant.  Or to put it another way, suppose the plant flowers earlier but its pollinating agent (an insect such as a hover fly) is not about, has not emerged from its over-wintering stage? What if there is a ‘late’ frost?   * Nature’s Calendar : The Woodland Trust joined forces with the Centre for Ecology & Hydrology to collate phenology records into Nature’s Calendar; this has some 3.5 million records- some going back to eighteenth century.