Silwood Park is part of Imperial College, a postgraduate campus, located some 25 miles west of central London, near Ascot. It is a centre for research and teaching in ecology and allied disciplines. The campus includes areas of wet woodlands, acid grasslands, traditional orchards and parkland. The veteran and ancient trees support an significant number of rare species of insects, lichens and fungi that depend on decaying wood. Silwood is the heart of the wildlife corridors for the surrounding area.  Read more...

The vibrancy and gaudiness of sunflowers is one of the delights of summer.  The common name "sunflower" generally refers to Helianthus annuus, whose round flower heads look like the sun.  Sunflowers are cultivated as food crops for humans, cattle, and poultry, and also for the garden. They typically grow during the summer and into early autumn, with the peak growth season being mid-summer. A field of sunflowers is a welcome relief from the acres of oilseed rape. The flower of a sunflower is not a flower but hundreds of small flowers (florets) massed together the better to attract pollinators.  The structure so formed is known as a capitulum.  The inner florets are arranged in spirals that conform to fibonacci sequences.  The pattern of these florets has been described mathematically by Helmut Vogel and it allows for the most efficient ‘packing’ of the florets in the ‘flower’ head. Before the flowers open,  the plants tilt during to face the sun, gaining more light for photosynthesis. This movement is known as heliotropism  and continues for a while when the flower head opens. This may help to attract pollinators.  Frequent visitors to sunflowers are bumblebees.  Sadly, like honey bees, bumblebees face a number of problems which include parasites.  However, recent research in the United States suggests sunflowers can help certain species of bumblebee.  If sunflower pollen is included in the diet of the common eastern bumblebee then it helps reduce infection by a parasitic protozoan Crithidia bombi.  This is a parasite that lives in the gut of bumblebees. When they pass out of the gut in cysts, they can be ‘picked up’ by the next passing bumblebee (or another insect, as the parasite is not too fussy). Once established in a bee, the parasite can affect the ovaries.  If a  queen is infected then the reproductive success of the colony is affected. Giacomini et al. have found that good nutrition is vital for bumblebee health and that sunflower pollen can be a huge benefit when it is included in the diet. They noted that the majority of the bees that consumed sunflower pollen had no detectable infection a week later. The pollen* significantly reduced infection by the parasite. So sunflowers are a visual feast for us, and an edible one for bumblebees and bees.  They also provide us with seeds.  The seeds are rich in monounsaturated and polyunsaturated fats, notably linoleic acid. The seeds also contain phytosterols which may contribute toward lowering the level of blood cholesterol.  The seeds may be pressed releasing sunflower oil, and the remaining ‘cake’ can be used as a protein rich animal feed.  The Ukraine and Russia are the top producers of sunflower seed. A somewhat different use of sunflowers is phytoremediation; using plants to remove toxic organic or inorganic compounds from soil.  After the disaster at the Chernobyl nuclear reactors in 1986, an exclusion zone with a radius of 30 km centred on the nuclear power plant was created. This was later expanded to include other heavily irradiated areas.  Even now, no one lives in the exclusion zone, but scientists and others may ask for permits to allow them to enter for short periods.  Fields of sunflowers were planted to ‘harvest‘ the radioactive metals (notably caesium-137 and strontium-90) from the soil. The sunflowers accumulated these elements in their tissues.  When the sunflowers had completed their growth, they were harvested and burnt, leaving only the radioactive ash behind. This material could then be vitrified (incorporated into glass) and stored underground in a shielded container. In Brazil, a study looked at the ability of different sunflower cultivars to remove nickel, copper and lead from contaminated soil.  Though phytoremediation with sunflowers proved to be an efficient and low-cost method for the treatment of contaminated soils, the cultivars varied in their ability to take up particular metals. “Cleaning up’ with sunflowers was tried after a tsunami hit the Fukushima Daiichi nuclear power station in Japan.  However, it was not very successful.   As different cultivars vary in their capacity to hyperaccumulate, so it is important to match the cultivar to the situation. Planting sunflowers in this case did little to improve the situation. This could be in part due to the sunflowers but also be associated with the soil type and the time that the caesium has had to bind to the soil particles. Understanding the mechanisms and detail of hyper accumulation is critical if sunflowers are to be used for phytoremediation in the future. Pollen is rich in secondary plant metabolites e.g. flavonoids, terpenoids, alkaloids, amines, and chlorogenic acids [caption id="attachment_35695" align="aligncenter" width="650"] field of sunflowers[/caption]  

The loss of pollinators, particularly honey bees, may bring about a synergy between pollinators such as hover flies and artificial intelligence technology.  Honey bees (and indeed bumblebee)s have been hit hard by habitat loss, pollution, the  extensive use of pesticides and the spread of viruses and varroa.  Bees provide an important ecosystem service, namely pollination.   bees provide the majority of plant pollination world-wide but the bees are fighting a losing battle and this represents a threat to food supplies.  In the United States, bee hives are 'bussed around' in a somewhat 'cavalier manner', indeed "Hives may be moved multiple times and several thousand miles per year" Read more...

Hawkweeds are wild flowers of dry, grassy places, but also to be found on walls, rocky places, and pavements. Some are regarded as invasive species in some parts of the world. The botanical genus Hieracium is known by the common name : the hawkweeds.  It is thought that the common name derives from the writings of Pliny the elder, who believed that hawks sprinkled sap from the plants into their yellow eyes to dispel dimness.  The genus is a member of the sunflower / daisy family: the Asteraceae. They are closely related to dandelions (Taraxacum) and sow thistles (Sonchus). There are thousands of different Hawkweeds;  but botanists classify British hawkweeds into about 340 “species”, many of which are quite rare. Identifying them is difficult and best attempted when there is fresh growth and new leaves.  The classification of the hawkweeds is difficult, partly because the plants use apomictic reproduction. This means that seeds that are formed without the usual processes of pollination and fertilisation.  Read more...

Plants and animals provide us with many important ecosystem services.   One critical ecosystem service is pollination; this is mainly done by insects - such as bees, bumblebees, moths and hoverflies. Insects are often attracted to flowers by scent, when volatile oils are released that act as chemical signals to ‘tell’ insects about their presence in the environment. This signalling is the result of a relationship between flowers and insects that has evolved over millions of years.  However, in relatively recent times, we (as a species) have been responsible for many changes to the Earth and its atmosphere.  Many gases and materials have been released into the air which have ‘mixed’ with the wide variety of natural scents and smells that are used for plant and animal communication. One such pollutant at low levels is ozone. Higher up in the atmosphere, the ozone layer prevents too much damaging UV light from reaching the Earth's surface.  However, at ground level, the oxidizing potential of ozone can cause damage to respiratory tissues in animals. Read more...

In Spring, or earlier if winter has been mild, queen bumblebees emerge from ‘hibernation’, from their nests.  They then need to feed, having more or less exhausted their bodily reserves during the cold of winter.  Their food comes in the form of nectar and pollen - both of which can be in short supply in early Spring. Whilst the bumblebees may need food, flowers also have a ‘need’-  pollinating agents - particularly bumblebees.   The inter-dependence of flowering plants and insects probably evolved many millions of years ago, back in the Cretaceous Period. Read more...

We are seeing increasing interest in the forestry industry in ‘Natural Capital’ – defined in simple terms as the wide range of benefits derived from nature. What is it? ‘Natural Capital’ refers to the value forestry and woodlands offer above and beyond commercial timber value. This includes the benefits and services that a woodland may offer such as cleaner air, flood defence, climate regulation, pollination or recreation and health benefits. This is not a new concept to owners of small woods who have long considered the value of their woodlands to be so much more than value of the trees themselves. Read more...

Bumblebees are important pollinators; their bodies are often seen covered with pollen grains.   However, when visiting certain flowers they have a special mechanism for releasing the pollen grains from the anthers (the special sacs on the stamens).    This mechanism is known as sonication or buzz pollination.   When visiting flowers of the potato / tomato family (the Solanaceae) or blueberries, they land on the flower, use their mouth parts to hold onto a stamen and then use rapid contractions of their (thoracic)  flight muscles to make the stamen vibrate.  The effect of these vibrations is to allow the pollen to be released from the tube-like anthers from a pore or small slits (poricidal stamens). Read more...