Nearly every report that one comes across says that many plant and animal species are under threat.   The causes are many but may be broadly summarised as  Fragmentation, loss or destruction of natural habitats (as a result of intensive and extending agriculture, roadways, railways etc) Pesticides and pollution (e.g. neonicotinoids, eutrophication as a result of fertiliser use) Impacts of climate change Some of the changes are more obvious in every day terms than others, for example, the drop in insect numbers is revealed by the car windscreen ‘test’ : the splatometer.   A survey of insects hitting car windscreens in rural parts of Denmark [using data collected between 1997 to 2017] found a decline of some  80%. There was a similar decline in the number of swallows and martins, (they depend on insects for their food). Read more...

In recent times, new or different threats have emerged to upset the balance of woodland and forest ecosystems.   In the 1960’s and early 70’s concern focussed on the effects of air pollution, particularly the effects of acid rain.  This type of pollution was characterised by the deposition / assimilation of sulphur dioxide and its derivatives (sulphuric & sulphurous acid), plus various nitrogen oxides.  This air pollution was largely due to industry and traffic. Some of the most striking effects of ‘acid rain’ pollution were seen in the coniferous forests of Germany - where it was termed : Waldsterben [Wald=forest plus sterben=to die].  Read more...

In winter, woods can seem a bit ‘naked’ and empty. Trees and shrubs have entered into a dormant state in order to survive the rigours of the winter months. Their buds await the signals that herald Spring. Many birds will have migrated to warmer climes, some animals will be hibernating. Many insects will be spending the winter as eggs or pupae, whilst herbaceous plants will over-winter as seeds, corms or bulbs.  But on the bark of many trees and on the surfaces of fences and walls, there will be lichens – they are there in summer, winter, spring and autumn.  Lichens are rather unusual in that they are an amalgam of two (or occasionally three) organisms : a fungus and algae. They are symbiotic systems, where two partners work together for mutual benefit (occasionally there are more than two partners). The fungus makes up the bulk of the lichen’s structure (known as the thallus), but the algae (green algae or cyanobacteria) are essential as they can photosynthesise and provide the organism with carbohydrates.  The nature of the biochemistry and physiology of the lichen symbiosis is largely due to the pioneering work of Dr David Smith at the University of Oxford in the 1960's and 70's. Read more...

Each day, our cities are exposed to pollution from cars, power stations, industry etc.  All of these release particulate matter (aka particulates) and various gases - such as carbon dioxide, carbon monoxide, sulphur dioxide, and nitrogen oxides.   The pollutants in many of our city streets frequently exceed the World Health Organisation (WHO) guidelines. Particulate matter is the sum of all solid and liquid particles suspended in air - it may include dust, pollen, soot, smoke and various liquid droplets.  These particulates are often divided into PM10 particles - that have a diameter of 10 micrometers or less, are inhalable and may pass into the lungs and then the bloodstream. And, PM2.5 particles have a diameter of less than 2.5 micrometers - these are very fine and often contribute to the haze in the air. Many particles form as a result of complex reactions between sulphur dioxide and nitrogen oxides. Read more...

Nitrogen pollution, in the form of nitrates, ammonia and various oxides of nitrogen, is a threat to ecosystems, ecosystem services and biodiversity.   Monitoring and measuring such pollutants in rain and air borne particles is expensive and, ideally, needs frequent samples. It has been estimated that some 400,000 tonnes of airborne pollution are deposited over Britain each year.  Research by Dr H Harmens et al at the Centre for Ecology and Hydrology (Bangor) has indicated that there may be a simpler and cheaper way of gauging nitrogen pollution  - through the assessment of the state of local moss populations. Read more...