Mites and bees. Varroa destructor also known as the Varroa mite is a small, external parasite of the honey bee : Apis mellifera. It is a mite. Mites are small members of the arachnids (8 legged arthropods).  The mite(s) attaches to the body of the bee and feeds upon its fat bodies; this weakens the bee. The mite also feeds on bee larvae. Not only that but the mite can act as a vector (‘distributor’) for five different viruses that also weaken the bees.  The varroa mite originally was to be found in Asia, and was parasitic on the Asian honeybee, Apis cerana.  Sadly, it has now spread to many countries and is responsible for significant infestations of European honeybee hives.  Over time, the mites have become increasingly resistant to chemical treatments. Now a program / study by the Universities of Exeter and Louisiana has been selectively breeding bees that identify and remove mites from their colonies [ie. showing hygienic behaviours].  They do this by removing infected larvae from the colony.  This is sometimes referred to as varroa sensitive hygiene.  Such colonies showed significant reduction in mite numbers and were more than twice as likely to survive winter as compared the ‘standard’ honey bees. The colonies also had reduced levels of three honey bee viruses The study looked at bee colonies across three American states, including California.  In the States, beekeepers move thousands of bee colonies to provide pollination services for many different fruit crops (e.g. almonds) in the Spring, thus winter survival of the colonies is vital. Historic rainfall records. was launched in March 2020 (during the 'first stay at home' / lockdown).  Members of the public were asked to help record digitally the information on pre-1960 weather sheets.  The Met Office archives had some 65000 sheets that contained the ‘scribbled records’ of thousands of weather stations/ weather recorders across the country.    Many of these sheets were the records of amateurs dating back decades, many before the foundation of the Met Office in 1854. One such 'recorder' was Lady Bayning of Norfolk, she was an early rainfall observer who took readings from 1835 to 1887.  Deciphering the idiosyncratic handwriting could not be done by character recognition software. However, the volunteers rose to the challenge and the task was completed in some 16 days. As a result, now the Met office has: Rainfall readings stretching back to 1836 Data from an increased number of rain guages  Identified the driest year on record - 1855 Identified the driest month on record February 1932 Identified the wettest month on record October 1903 Note : [The Met Office was founded by Robert Fitzroy, the captain of HMS Beagle, that carried Charles Darwin on his epic voyage around the globe. Fitzroy essentially established the science of weather forecasting] Trees on the move ? We know that trees can ‘move’.   They did so at the end of the last Ice Age (some 12,000 years ago).  As the glaciers retreated so trees started to return to the newly exposed soils as the temperature warmed.  The discovery of the remains of acorns in archaeological digs, and analyses of fossil pollen records indicates that even oaks colonised areas of the UK at the rate of nearly a kilometre a year.   Similarly, Norwegian Spruce colonised areas around the Baltic Sea and the boreal forests grew and expanded - long before humans arrived there.   Now we have warming temperatures as we have moved into the Anthropocene.  In order to survive changes conditions, plants, like us, have to move. So, like after the ice Age, plants and trees are on the move.  Scientists in California have calculated that as a result of global temperature changes, plants need to move northwards (or upwards) at the rate of 400+ metres a year.  In the eastern parts of the United States, it has been estimated that trees were shifted north and westward at a rate of 10 / 15 km per decade.  The conifers going north. Whilst oaks and birches going west.  In Scandinavia, which has experienced significant aspects of global warming, birch saplings are now found higher up mountains, gaining 500 metres in elevation within two decades.  Pines, spruces and willows are also growing at higher altitudes than previously.  Similar colonisations of  hillsides and ‘bare valleys” are seen in Alaska of alder, willow and dwarf birch. Further information here [caption id="attachment_38737" align="aligncenter" width="700"] Busy bee[/caption]

LASI is the Laboratory of Apiculture and Social Insects at the University of Sussex. It is particularly noted for its research work on bees. Recently, Dr Balfour and Professor Ratnieks have published a study on the rôle of certain 'injurious weeds'.   Five of our native wildflowers fall into this category : Ragwort (Jacobaea vulgaris), Creeping or Field Thistle (Cirsium arvense), Spear or Common Thistle (Cirsium vulgar), Curly Dock (Rumex crispus), and Broadleaved or Common Dock (Rumex obtusifolius).  They compared the ragwort and the thistles with plants like red clover and wild marjoram (often encouraged / sown on field edges etc).. They found that the 'injurious weeds' were particularly 'effective' at attracting pollinators, not only did they they attract greater numbers of pollinators than clover etc, but also a greater range of pollinator species.  This was ascribed to the open nature of their flowers and their generous nectar production.  This brings into question the control of species like the ragwort, as it is clearly important to pollinators (as are some 'botanical thugs' - like brambles).  Ragwort contains chemicals that are toxic to livestock, causing liver damage; it has been blamed for the deaths of horses and other animals. At the Smithsonian, Kress and Krupnick have analysed the features of some 80,000+ species of plants to see how they might fare in the Earth's changing climate (the Anthropocene).  This may seem like a large number of different plants, but represents approximately only 30% of the known species of vascular plants.  There is not enough information of the remaining species to make a reasonable guess as to how they might react to climate change;  a reflection on how little we actually known about our 'botanical resources'.  Sadly, they conclude that more plants will lose out than win.  Particularly at risk of extinction are the Cypress family (which includes the redwoods and junipers) and  the Cycads, whereas black cherry might be a winner. As was reported previously in the woodlands blog, there is a difference between the leaves of the redwoods found at the top of the tree and those lower down.  Those at the top are small, thick, and fused to the vertical stem axis; this fusion of leaf and stem creates a relatively large volume of tissue and intercellular space that can store water. The leaves in the lower part of the crown by comparison are large, flat and horizontal to the stem axis.   Now scientists as the University of California (Davis) have further investigated the role of these leaves.  They now believe that the different leaf forms help explain how the exceptionally tall trees are able to survive in both wet and dry parts of their range in California.  In the rainy and wet North Coast, the water absorbing leaves are found on the lower branches of the trees.  In the Southern part of the redwoods range, the water collecting leaves are found at a higher level to take advantage of the fog (and rain, which occurs less often).

Wetlands. In the past, many areas of wetlands have been drained and ‘dried out’.  Now it is recognised that this is counter-productive in terms of carbon storage / sequestration and biodiversity, so there are now measures to restore wetlands. The hope has been that restoration of wetlands will do much to restore the variety of plants and animals (and help carbon storage).  However, research by the University of Copenhagen suggests that such projects might be ‘struggling’. The study examined ten wetlands (near the River Odense) that were restored between 2001 and 2011.  The restoration involved the removal of drains and ditches, and allowed streams to meander again instead of flowing in ‘straight channels’.  The aim of the project was primarily to reduce the leaching of nitrogen and phosphorus from adjacent farmlands, and hope to see greater diversity of plants (e.g. marsh orchids, globeflower, tussock-sedge and ragged-robin).   The ‘restored’ wetlands were botanically poor (whether restored in 2001 or 2011), they had only a quarter of the plant species compared to natural wetlands.  This may be due to  the continued input of nutrients (from agriculture), which encourages species that are ‘nutrient hungry’ at the expense of others. the ‘difficulty’ of wetland species to disperse from one area to another. It may be that future restoration programs will need to include planting / seeding of additional wetland species. It has been suggested  that it could take the best part of a hundred years for the restored wetlands to resemble natural wetlands. Redwoods and relatives. Previous posts have talked about the special features of the giant redwoods (their height, age etc).  Over the last 150 years, they have ben subject to the pressures of commercial logging, clear felling and more recently high intensity fires.  Indeed, the fires have been of such an intensity that seed banks in the soil have been destroyed. Now they have been subject to genomic analysis, that is their DNA has been analysed and sequenced.  The first conifer genome to be sequenced was that of Norway Spruce, then that of loblolly pine.  These suggested that conifer genomes are large (3 to 10 times larger than the human genome), with repetitive sequences.  Coast Redwoods are hexaploid, that is, they ave six copies of each chromosome (we are diploid, that is, have only two copies of each chromosome).   The DNA of a coast redwood has  27 billion base pairs of DNA, the giant sequoia has 8 billion; by contrast we have circa 3 billion.   It is hoped that the Redwood Genome project will see the restoration of areas of coast redwood and giant sequoia that have been lost over the years. The genomic analysis will help inform and guide management strategies, ensuring genetic diversity in the newly planted tree seedlings. Such a strategy will (hopefully) enable newly planted areas to survive and thrive — in the Anthropocene. More on chromosomes Just as it has recently been shown that Coast redwoods are polyploids (i.e. have extra sets of chromosomes), so recent research in the Czech Republic has shown that the common nettle [Urtica dioica] has different ecological ‘preferences’ depending on its chromosomal status.  Nettles can be diploid (2n = 26) or tetraploid (2n = 52).  The tetraploid nettles seemingly have a broader ecological tolerance and a wide geographical distribution, whilst the diploid nettles occur in a narrower range of ecological conditions. Details of this research can be accessed here (note link opens a PDF) and Plants for a future has lots of information on nettles.    

The woodlands blog has reported on the anthropocene - how human activity is creating a geological era characterised by human impact on the Earth.  Now a report finds that human-made (artificial) material will this year surpass the sum total of all living material (biomass) on earth. https://www.nature.com/articles/s41586-020-3010-5 A Swedish study has shown that crop yield can be enhanced  by ensuring that woodland and grassland areas are present in the vicinity of crop fields.    If the landscape is more diverse in terms of plants and habitats, then the number of pollinators (bees snd bumblebees) is greater.   Read more...

As a species, we humans have only been present on the Earth for a ‘blink of the eye’ in geological terms.   The Earth is approximately some 4.6 billion years old. Geologists have divided up these years into a number of geological periods or epochs - from the Pre-cambrian (from the formation of the earth until about 540 million years ago) to the most recent - the Holocene, which started at the end of the last Ice Age - about 12,000 years ago. Modern Humans emerged out of Africa probably some 200,000 years ago, and since that time they have increased massively in number.   At the end of the C18th , there were probably about one billion people; now there are over seven billion. We have changed the Earth in many ways.   Read more...