Natural habitats have been disappearing for a long time - as a result of human activity.  The last century saw hundreds of miles of hedgerow disappear, and the same is true for ponds and wild flower meadows.  Agriculture, transport networks and cities have expanded - woodlands have become fragmented.   Now, sadly we have seemingly daily reports of our rivers and seashores being polluted with sewage.  Indeed, thousands of such incidents have been reported and many rivers and seaside resorts are now unsafe places to swim (or row?).  Clearly, the infrastructure (much of it victorian) is unable to cope with the demands placed upon it.  Surfers against sewage have collected and collated information about sewage, and on their web site there is a map of coastal areas experiencing sewage discharge. If this situation was not bad enough,  run-off from major motorways is also being discharged into our rivers and streams.  Indeed, the Environment Agency has acknowledged this as a serious issue, accounting for some 18% of ‘water quality failures’ in England.  Like sewage, it is damaging. So what does this road run-off water contain?  It seems to be a mix of particles from tyres, clutch and brake pads, motor oil, transmission fluid, coolant, gear oil, and power-steering fluid. In addition, rust or corrosion from the car / vehicle body and galvanised parts can release iron, zinc, and aluminium. Modern tyres contain natural rubber, synthetic rubber etc. so when you brake, or speed up, the tyres shed thousands of tiny rubber and plastic fragments. They form as a result of the friction between the tyre and the road; they are referred to as ‘Tyre Wear Particles’ or (TWPs)*; and are a significant source of microplastics.  Microplastic are seemingly everywhere, in the oceans, in habitats across the world and even in us.  Scientists have found even microplastics in human semen, and also follicular fluid ( the fluid that surrounds a developing egg in the ovary). During and after heavy rain, TWPs and other materials are washed off the roads, with most entering stormwater networks, which channel the run-off into rivers, streams etc. Due to their density,  the TWPs etc sink and form a sediment layer.  The BBC has reported on the ‘black gunk’ in the River Lambourn (Berkshire).  The Lambourn is a chalk stream with crystal clear water as it makes it way through Welford Park, before passing underneath the M4.  Thereafter, it turns brown and murky. This has consequences for the invertebrate animals that live in the waters of the stream or on the stream bed. It is possible to mitigate some of the effects of this run-off / stormwater. For example,  near the A38 in Devon the National Highways have built a reed bed . This filters the run-off from the busy road. There are only 210 true chalk streams worldwide, and most of them are in England.   For example, the Test and Itchen in Hampshire, the Wensum in Norfolk and the Piddle in Dorset.   They are a unique contribution to global ecosystems. The National Highways is aware of the pollution problem across the road network and is using a computer model to identify which stormwater outfalls to tackle. More than a thousand locations that are "potentially high risk" have been identified.  Under its current plans, a limited number of high-risk sites will have had a mitigation in place by the end of last year. *TWPs may be swept up into the atmosphere and transported to remote regions like the Arctic.

Bee:wild [https://beewild.rewild.org] is a new science-led, global campaign, which aims to help and save pollinators - particularly bees.  The woodlands blog has reported on the decline in many insect populations in recent times - referring to the ‘insect apocalypse’, the ‘windscreen test’,  and the ‘splatometer’. The causes for insect loss are many but critically important are : Habitat loss and fragmentation The extensive use of pesticides, herbicides & fungicides. These may be coupled with other issues such as climate change, and pollution from fertilisers into rivers and streams.  However, in recent times, we may now need “to add to the mix” - Wars and conflict.  These can result in changing patterns of agriculture so that the range of crops grown is reduced, which means there are less foraging opportunities for pollinators. The ubiquity of plastics. Specifically microplastics and nano plastics.  Microplastics come in part from larger plastic pieces that degrade into smaller pieces, but also from microbeads.  Microbeads are very small pieces of polyethylene plastic that are added to health and beauty products, such as certain skin cleansers and toothpastes. Now microplastics are to be found everywhere from the deep oceans, to Arctic snow and Antarctic ice. They are also found in the hives of honey bees.  Quite what their effect is on bees or indeed many other organisms (including us) is not yet clear. Artificial light.  Much of our world is illlluminated 24/7.  Towns and cities rarely experience total darkness, even the countryside is lit up by the lighting on roads and motorways.  This artificial light is not without effect.  Areas ‘bathed’ in light may Deter nocturnal moths from visiting flowers, reducing pollination and egg laying. Make the night flying moths ‘easier targets’ for predators (such as bats). Affect the feeding habits of moth caterpillars. Air and water pollution.  Both air and water are increasingly filled with a ‘cocktail’ of chemicals, some derived from the extensive use of pesticides (insecticides, herbicides, fungicides, some come from use of fertilisers).  Particulates released from car tyres and brake pads contribute to the ‘chemical smorgasbord’.  Whilst the effect of any given chemical may be sub-lethal, small, or non existent the combined effect of the mixture may be significant, even deadly.   Wild fires.  Add into this anthropogenic concoction mentioned above, the chemicals released from wild fires - such as those seen recently in Canada, Siberia, Australia and the United States.  These fires not only release a complex mixture of particulates and chemicals, they also destroy habitats for pollinators.  The sheer scale of these fires makes the recovery of ecosystems that much harder. Bee:wild [https://beewild.rewild.org] suggests a number of measures to help pollinators : A swifter move to electric cars to reduce levels of atmospheric pollution Production of crops with enhanced nectar and pollen production to benefit pollinators Creation of more flower-rich areas, for example, within solar farms Use of RNAi therapy to specifically target pests and not beneficial insects.  RNA interference is a technique that uses natural cellular processes to silence or reduce the expression of particular genes in a particular organism.  Thus, it might render a pest sterile. Introduction of measures to reduce the use of ‘our’ chemicals, used to enhance the growth of crop or animals. Such measures when coupled with the creation of urban rich flower gardens, rewilding and the protection of remaining areas of natural habitats will help pollinators, and insects in general.

Tree survival and drought. Researchers at the University of California have been working on a method that helps predict whether forests / woodlands can survive periods of drought.  As climate change is altering patterns of snow and rainfall, so periods of drought are likely to become more common. Forests are important in terms of carbon sequestration, that is, they take up carbon dioxide from the air and convert it into sugars, starches etc that are stored in the leaves, branches, stems and roots.  However, in order to assimilate and convert carbon dioxide (in photosynthesis), trees (indeed all plants) need a supply of water.  When water is limited, trees need to make use of their reserve materials.  Just as we make use of body reserves of fat and glycogen when food / diet in inadequate. However, reserves can only sustain a tree for a finite period of time.  If drought persists, the tree reaches a ’tipping point’ and it will die.  The researchers studied a forest in the Sierra Nevada that experienced a period of drought between 2012 and 2015.   During this period, millions of trees died.  The team recorded rainfall, soil moisture and temperature in the forest AND the amount of carbon dioxide that the trees absorbed, and their reserve materials.  They found that the trees were able to maintain function / health after the onset of the drought but with the passing of time, the trees exhausted their reserves and were unable to use / convert carbon dioxide into food.  They had reached the tipping point and died.   The methodology of this study was called CARDAMON (carbon data assimilation with a model of carbon assimilation); it is hoped that it can be used to evolve strategies to enhance forest and woodland resilience in the face of climate change. Pollinators. [caption id="attachment_35902" align="aligncenter" width="675"] hoverfly[/caption] University researchers from the UK and Finland have been trying to determine the most effective pollinators of crop plants, like strawberries (and other fruits).  Plentiful and effective pollinators are needed to ensure a good harvest of the fruits. The researchers studied the pollinators at three strawberry farms through the (long) growing season for the fruit.  They adopted two approaches : They caught the insects that visited the strawberry flowers and analysed the pollen they carried in detail (pollen load and type). They also counted the number of flower visits by the different insects, (a quick way to identify key local pollinators). Many insects were identified, including :-  European drone fly :           Eristalis arbustorum Honeybee :                               Apis mellifera Levels drone fly :                   Eristalis abusivus Buff tailed bumblebee :     Bombus terrestris White tailed bumblebee :  Bombus lucorum Common drone fly :             Eristalis tenax Red tailed bumblebee :      Bombus lapidarius Early bumblebee :                Bombus pratorum Bent-shinned Morellia :   Morellia aenescens Hoverflies are true flies, that is, they belong to the order Diptera or true flies, as they have a pair of wings and a pair of halteres (balancing  / orienteering organs used when in flight). Several of the flies in the genus Eristalsis are known as Drone Flies (due to their resemblance to honey bee drones).  The larvae of Eristalis  species are commonly found in putrid / stagnant water and sometimes referred to as “rat-tailed maggots”. It was noted that pollinators also made use of the wild plants to supplement their diets, as strawberries alone cannot meet the nutritional needs of pollinators.  ‘Elsanta’ strawberries have a relatively low sucrose and protein content in both their nectar and pollen. The precise  order of importance of pollinators varied between farms.  Bee (Apis and Bombus) species  and hoverfly (Eristalis) emerged as key pollinators. The European drone fly was the most important pollinator at two of the three farms studied, evidence that hoverflies can be effective pollinators.  One farm had commercial hives of the honey bee but they were less significant than the activities of of the hoverflies and bumblebees. The abundance of a particular insect, coupled with its active period were /  are important determinants of pollinator importance.  Sawdust and plastics - a possible use?. Plastics represent a relatively new, but persistent and major form of pollution (on land, in the sea, indeed everywhere).  Whilst many plastic objects are instantly visible in the form of discarded bottles, fast food containers, many plastic pollutants are in the form of very small particles of plastics  - nano and microplastics.  The concern is that we and other organisms are taking these microscopic particles into our bodies from our food / drinking water. However, it is possible that plant materials may offer some ‘solutions’.  Water that contains micro and nano plastics can be filtered through sawdust that has been treated with tannic acid.   Tannic acid is large molecule, its molecular formula is C72H52O46 .  Tannic Acid is found in certain plant galls (swelling of trees caused by parasitic wasps) and in the twigs of certain trees, such as Chestnut and Oak.  The wood sawdust contains fibres of cellulose, combined with hemicelluloses and lignin.  Water can flow through this material by capillary action.  This plant-based filtration (known as bioCap) of plastic-laden water is capable of dealing with a wide range of nanoplastics (PVC, PET, polyethylene etc), and tests with mice suggest that the filtered water may be sufficiently free of plastic to pose little risk.  

In the C19th, many objects were made from ivory.  The ivory came from the slaughter of elephants.  As elephant populations fell, so the search for a suitable substitute began.   Celluloid was one of the first materials used but it was easily combustible. It was soon replaced by other materials like Bakelite,  this was the first entirely synthetic plastic.  It was made from phenol and formaldehyde.  It was used for toys, radios, telephones etc.   Bakelite  was tough, heat resistant and  did not conduct electricity.  Other materials followed, and many different plastics are produced today; for example, polyethylene (which is widely used in product packaging) and polyvinyl chloride [PVC] (which is used in construction and pipes because of its strength and durability).  The trouble is that plastics are just so useful.  Plastics are cheap, lightweight and durable.  Durability is a good quality when the plastic is being used but not when it is discarded, for example, into landfill where it may take centuries to degrade.  Sadly, many consumers leave empty bottles / containers / wrappers in the streets, on the beach, at picnic sites etc.  As most plastics are made from fossil fuels / oil, the manufacture of plastic is also a driver of climate change. Since the middle of the twentieth century, it is estimated that some 8.3 billion tonnes of plastic has been produced. Sadly much of this has ended up in landfill, in rivers, the soil, and the oceans - with significant effects of wildlife. Plastic pollution is ubiquitous. For example, the Great Pacific Garbage Patch, which is a collection of large areas of plastic and other debris in the North Pacific Ocean. It has been estimated that it contains some 1.8 trillion pieces of plastic .  It is a serious threat to marine life such as whales, sea turtles, fish, and birds.  Plastic items are discarded with little thought to the consequences.  Bottles etc can end up as traps for many animals and a few years back we (at woodlands) found a child’s plastic boat dumped in a woodland (see featured image above).  Sometimes, we see the distorted remains of plastic tree guards ‘strangling’ young trees. Plastic carrier bags (sometimes filled with dog faeces)  can end ups suspended from trees / shrubs in woodland, or caught on wire fencing, waving n the wind. Discarded plastic items come in all shapes and sizes; those that are 5mm or smaller are termed “microplastics.”  Microplastics come in part from larger plastic pieces that degrade into smaller pieces; but also from microbeads.  Microbeads are very small pieces of polyethylene plastic that are added to health and beauty products, such as some skin cleansers and toothpastes. Now microplastics are to be found everywhere from deep oceans, to Arctic snow and Antarctic ice.  They are found in foodstuffs and drinking water.  One investigation found that if parents prepare baby formula by shaking it up in hot water inside a plastic bottle, their child might swallow tens of thousands of these microplastic particles each day.  The movement of these particles through ecosystems is  graphically summarised in this article.   There is currently much discussion and research about how these microplastics will impact on the environment and different organisms, including us.  Because they are so small and to be found widely in the environment,  they enter organisms and food chains.  Apart from the plastic in these particles, they may also contain chemical residues of  plasticisers, drugs, and pharmaceuticals, and heavy metals may stick to them.  Sometimes, sewage sludge may be used as fertiliser and this can contain nanoplastics.   Also, treated wastewater is used for irrigation  purposes and this again may be a source of plastic.  Research indicates that earthworms in microplastic ‘enriched’ plant litter grow more slowly and have a shorter life span, and there is evidence that the gut of earthworms becomes inflamed after exposure to microplastics.   Earthworms are important in aerating the soil and transporting materials such as dead leaves from the surface to deeper in the soil, they also 'inadvertently' transport micro-plastics.  Springtails, a group of soil micro-arthropods (Collembola) can also help move micro-plastics in the soil.  The movement of microplastics through the soil makes these materials ‘accessible’ to other soil dwellers but it is not clear if they pass along food chains (as has been the case with pesticides). Whether nano-plastics are taken up by or affect plants - again is not yet clear.  However, the chemicals released by plastics such as phthalates may taken up by plants. There is a significant risk of physical and physiological damage to organisms and ecosystems by these micro-plastics *. The particles also get into the human body and the consequences for our health are, as yet,  unknown. further information on nanoparticles etc : https://www.sciencedaily.com/releases/2022/04/220420133533.htm

Plastic mulch - white (though sometimes black) polyethylene strips, each about a meter wide, can occasionally be seen stretching across fields.  Crops grow through the slits or holes in the thin plastic sheeting. The sheets are used because they help to conserve water,  suppress weeds,  reduce soil compaction boost soil temperatures reduce waste - by keeping ripening fruit off the soil Read more...