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.    

Many of us taking our daily walks are noticing the very strong signs of Spring with new growth everywhere.  Two classic woodland and hedgerow ingredients are at their best for picking in early Spring, nettles and wild garlic, both are packed with goodness and combined, they make a very tasty and healthy lunch.   It can be incredibly satisfying to forage and make something delicious, with no need for a shopping trip. Add a few extra vegetables, whatever you have available at home. Stinging nettle (Urtica dioica) has been a staple in herbal medicine since ancient times. Most concentrated in the growing tips, the plant contains a high content of nutrients including vitamin A, vitamin C (ten times more than an apple), and vitamin K along with easily absorbed calcium and iron. Read more...

Stinging nettles (Urtica dioica) are widespread across the UK.   They are found nearly everywhere; in woodlands, hedgerows, gardens and on disturbed ground. Nettles have been found in and around human settlements since the earliest of times; they probably formed part of the diet in Stone Age times.  Nettles also provided fibre for clothing.  A piece of nettle cloth has been found in Denmark's richest known Bronze Age burial mound (Lusehøj). It is associated with the burial of a rich and powerful man - after the burning of his body, his bones were wrapped in a cloth made from stinging nettles and then placed in a bronze container. Stinging nettle pollen is often to be found in soil sample cores, suggesting it is one of our native plants though human activity and movement may helped it to extend its range.  Nettles can tolerate a wide variety of soil conditions, though they seem to like moisture, and soils rich in nitrate and phosphate. In favourable conditions, they can grow to a metre or more in height. There are patches of stinging nettles that mark phosphate-rich debris from abandoned villages and sites of human occupation from more than 1500 years ago. Nettles have the potential to grow and expand in woodlands, perhaps aided and abetted by the increasing levels of eutrophication (nitrate / phosphate enrichment from air borne pollution).  Indeed, they can become 'botanical thugs' overwhelming other members of the ground flora  / herb layer. Read more...

Biotic homogenization has been defined as follows "the process by which species invasions and extinctions increase the genetic, taxonomic or functional similarity of two or more locations over a specified time interval. Biotic homogenization is now considered a distinct facet of the broader biodiversity crisis having significant ecological, evolutionary and social consequences."   Basically, it refers to an increasing similarity in the make-up of the plant communities found in different places - a bit like High Streets, each of which used to have a special character or 'signature', now it is difficult to distinguish one from another. In many cases,  biotic homogenization involves the replacement of local floras and faunas with 'introduced species', sometimes referred to as aliens.   Examples of plants that have been introduced and spread are himalayan balsam and japanese knotweed.   Read more...

Nitrogen is an important plant nutrient.  Generally, it is taken up in the form of nitrate (NO3) and it is used in the formation of amino acids, proteins and the constituents of the genetic material (DNA).  Some plants fix atmospheric nitrogen through the use of symbiotic bacteria in root nodules. However, modern / intensive farming involves the addition of nitrogen compounds in the form of manure, sewage sludge and chemical fertilisers. Couple this with the aerial deposition of nitrogen compounds, estimated at 400,000 tonnes / yr from car exhausts etc. (in the form of ammonia, nitrogen oxides) to give the total burden of nitrogen pollution. Pollution from such widespread sources is referred to as diffuse contamination. Read more...

The first shoots of young nettles, Urtica dioica, are very good for cooking both soups (see recipe in wild food post) and tea. According to several sources it is also good nutritionally: a source of iron, calcium and folic acid. Read more...