Blog - beetles
Many hedgerows were planted originally to keep livestock, such as sheep, cattle, pigs, chickens in specific areas. Some hedgerows were planted to define boundaries – ‘who owned which bit of land’. Hedgerows often surround fields. The word ‘field’ comes from Old English ‘feld’, meaning 'an area of felled trees / open country'. The establishment of many hedgerows was associated with the process of enclosure; a change in land use from arable to pasture (for sheep). Open fields and common land were enclosed by hedgerows, over many years the landscape of England changed. The C20th witnessed the opposite process, the removal of hedgerows for the creation of larger fields to accommodate larger machinery. In the decades following the end of the second Word War, it has been estimated that a quarter of a million miles of hedgerow have been ripped out / lost. Fortunately, there are now policies in place to halt or even reverse the loss of hedgerow. Hedgerows are recognised as an integral part of our landscape and play an important role in the maintenance of biodiversity. They provide habitats for a variety of animals and plants. Many species of birds nest in hedgerows, such as song thrush, yellowhammer and tree sparrow. Different species favour different heights within the hedgerow. Some species nest near the ground such as wrens and dunnocks, whereas others nest higher up (eg. Bullfinches). The greater the variety of plant species in a hedgerow, the better the supply of pollen, nectar, fruits and seeds. Ivy for example will produce flowers late in the year and offers a source of nectar and pollen. Hawthorn, blackthorn and holly offer fruits in the winter months for birds and small mammals. Hedgerows and hedges have to be be maintained. Such management may involve planting of trees or shrubs to fill gaps, coppicing, laying or cutting back. [youtube=http://uk.youtube.com/watch?v=Andv7a0NPEc 425 350] However, the effects of pruning and cutting back during the bird-nesting season can be disastrous. Mechanical flailing of a hedgerow is fast, effective and the regrowth is generally slower, but its effects can be particularly bad on birds. They may abandon their nests and / or their eggs or chicks may be destroyed. The pruning / flailing may also reduce the insect populations of the hedgerow (or other other food sources) on which the birds depend. Hedge pruning maintenance is :- ideally undertaken outside of the nesting season. and only done every second or third year. [caption id="attachment_25527" align="aligncenter" width="600"] A flailed hedge[/caption] Hedgerows also support vital insect pollinators : butterflies, hover flies, moths and bees. These insects help with the pollination of crops such as oilseed rape, legumes and fruit trees. Other insects can help with crop yields by predating upon crop pests, such as green fly and blackfly (these may spread viral diseases on crops such as sugar beet). Insects may overwinter in the hedgerow and move into the fields come the Spring, as the aphids start to increase in number. If trees are left in situ, they may achieve veteran status. Then their rough bark, cracks, holes and dead wood will support a diverse range of species. Owls, kestrels and bats may come to nest. There are also niches that offer opportunities for epiphytes, mosses and lichens. The dead wood may be home for saproxylic beetles. Hedgerows also act as corridors linking to other hedgerows, woodlands etc along which animals can pass (for example, hedgehogs and other small mammals). Hedgerows provide important wildlife corridors across agricultural landscapes. They provide food for insects, small mammals and birds (due to the range of plants and their different flowering and fruiting times). They provide nesting and roosting sites for birds and bats, and ‘homes’ for a variety of small mammals. Many insect species over winter in hedgerows. The trees and woody shrubs help with carbon sequestration. Hedgerows offer a windbreak, reducing wind speed and hence lowering soil erosion, they may also offer shelter to animal stock. The roots also help stabilise the soil. [caption id="attachment_40483" align="aligncenter" width="675"] Hedge with beech, nettle, dog rose, brambles, hazel and ash - amongst others[/caption]
Flowering plants and pollinators
Plants have existed for hundreds of millions of year - as algae, mosses, liverworts, ferns but flowering plants only appeared about 140 million years ago. The exact timing of their appearance is a matter of some debate (see article) They have been a massive evolutionary success, there are perhaps 300,000 to 400,000 species world wide. They reproduce using pollen. This is used to fertilise the ovules and produce viable seeds. Most plants rely on insects to transfer this pollen to the ovules, indeed over 80% of flowering plants have relied on insects for this service. To this end, flowering plants (Angiosperms) have evolved a number of inducements to attract insects : colour, scent and nectar. When we think of pollinators, we generally tend to think of bees, bumblebees, hover flies. But when flowering plants first evolved, fossil evidence suggests that many of these flowers were quite small so it is probably that the first pollinators were also quite small, and hence able to access these small flowers. The first pollinators were probably small flies, midges or beetles (more than 77,000 beetle species are estimated to visit flowers). Quite when bees (and their pollen collecting activities) evolved is not known. A recent analysis of the "family tree" of the families of flowering plants indicates when different plant families evolved and when various forms of pollination emerged. Insect pollination is / was clearly the most common method of pollination, and was probably the first means of pollination. This analysis also indicated that other means of pollination (involving small mammals, birds, bats) have evolved several times, as has wind pollination. Wind pollination seems to have evolved more often in open habitats and at higher altitudes , whereas animal pollination is associated with closed canopy tropical forests. The pollen of insect pollinated flowers is significantly different to that of wind pollinated species. Flowers that are insect pollinated tend to produce pollen that is heavy, 'sticky' and protein-rich. Pollen is an important constituent of the diet of many insects. Wind pollinated species by contrast produce large quantities of pollen, the grains being light and small.
Promoting wildlife in gardens
Reports in the papers and electronic media have made us aware that many forms of wildlife are under threat. This threat is wide ranging - from the destruction of tropical rain forests, coral reefs, the loss of species-rich meadows, the insect apocalypse - indeed where does this loss of plant and animal species end? One small positive observation amidst the doom and gloom is the findings of The Biodiversity in Urban Gardens project [BUGS] at the University of Sheffield. The original study focused solely on Sheffield and finished in 2002, but it was then extended to five cities across the U.K. Professor K Gaston who led the study is now working at the University of Exeter. The original study was important in that it revealed within Sheffield city, there was 33 km2 of wildlife habit was available within the city 360000 trees in the city limits 45000 nest boxes 25000 ponds and 50000 compost heaps Furthermore, there were in excess of a thousand plant species (flowering plants, ferns and conifers) and a diverse collection of invertebrates (bumblebees, hoverflies, beetles and spiders). Whilst the diversity was in no way comparable to that of an ancient woodland (with veteran oak trees etc) or indeed of wetlands, it is significantly better than that found on farmland - particularly in those areas where the farming is intensive and characterised by monocultures (e.g. oil seed rape extending to the horizon). Farmland now occupies some 70% of the landscape. Gardens, parks and urban areas are therefore an important resource for wildlife. It is important as house building proceeds, on both brown and green field sites, that the associated gardens continue to provide ‘sanctuaries’ for wildlife, for example, by avoiding large areas of hard standing for cars (which also encourage rain / water run off - which can overwhelm the drainage systems). Professor Gaston has emphasised the importance of ‘dimensional complexity’ in gardens; that is a variety of trees, shrubs and plants of different shapes and sizes. This provides a range of different niches / habitats for wildlife. Of course, in gardening to promote wildlife, there are the additional benefits (for householders) of physical and mental well-being. Remember later this month, there is the Big Garden Birdwatch, organised by the RSPB. For further information, click on the image below:- [caption id="attachment_36525" align="aligncenter" width="670"] Ladybird 'stalking' aphids[/caption]
Offer a home to a beetle, or two?
Across the globe, insects are in decline. There are several (over-lapping) causes of the decline, ranging from habitat loss, the effect of artificial lighting, the use of agrochemicals (e.g. the neonicotinoids) and herbicides, such as glyphosate. The latter is one of the most commonly used weedkillers and might not be expected to affect insects. However, recent research has shown that it can affect the formation of the hard exoskeleton of beetles. It does this by affecting their symbiotic bacteria; these contribute an essential building block (an amino acid) for the exoskeleton. Early summer should be ‘peak beetle time’ Read more...
Ladybirds or bishy barnabees.
In Norfolk, a ladybird is sometimes referred to as a bishy barnabee.; this rather curious name is explored in this article in The Spectator from last year. Ladybirds are beetles and are easy to recognise. Most have dome-shaped bodies, with an oval outline and three pairs of jointed legs. The most common ladybirds have bright red wing cases with black spots covering their bodies. Others are yellow with black spots, some white and brown, or even striped. It has been estimated that there are some five thousand species of ladybird across the world, with 40+ species in the British Isles. Their bright colour serves as a ‘do not eat me’ warning to would-be predators, apparently they have a bitter taste. Birds such as swifts and swallows eat ladybirds, as do some spiders, frogs, wasps, and dragonflies. When challenged, ladybirds can produce an ‘unpleasant’, yellow, oily fluid; or they may ‘play dead’. The pine ladybird when under threat ‘clamps’ itself to the surface that it is resting on. Bright colours are used as a defence mechanism in a number of insects. Read more...
Helping Hands for Hedgehogs
Hedgehog numbers have declined in recent years, perhaps by as much as 50% in areas such as East Anglia. Though they are not doing well anywhere (with the possible exception of Uist in the Hebrides), there is a suggestion that urban hedgehogs are doing somewhat better than their country cousins. Read more...
Woodland moths and butterflies.
There are many types of woodland, which may be broadly categorised by the dominant type of tree(s) - thus there is, birch woodland, oak woodland, beech woodland etc. The flora and fauna of these different types of woodland varies though there can be similarities. Some species, such as brambles and ivy can live in a variety of conditions whilst other plants / animals have very specific requirements. This is certainly true for various animal species - for example, butterflies and moths. For example, the Brimstone (a pale yellow butterfly) has larvae (caterpillars) that need to feed Read more...
What are resilient woodlands?
Making woods resilient has become the latest fashion in forestry as illustrated by the RFS conference being organised with the Woodland Trust in Birmingham at the start of October.ˇ Resilience in this context means resilient both to diseases and to climate change effects. Much of the thinking is based on the 2015 British Woodlands Resilience Survey which has been organised by the Sylva Foundation and sponsored by Oxford University, the RFS and the Woodland Trust.ˇ There have also been useful presentations on the subject such as the one given at the CONFOR Show (Confederation of Forest industries) show at Longleat, Wiltshire in early September 2015. Read more...