Sadly, the number and range of various species in the U.K. is decreasing, biodiversity is falling. Our wildlife-rich areas are actually separated and fragmented, by tracts of intensively-farmed land, by motorways and roads, and the ever increasing spread of urban areas. The dispersion and isolation of wildlife areas makes it difficult for both plant and animal species to move. The ability to move around is ever more important as a result of climate change. Rainfall patterns and average temperatures in different regions are changing, extreme weather events are more common. For a species to stay in its ‘comfort zone’, it may need to move ‘northwards’ as climate change continues.
During the last Ice Age, much of the UK was covered with a layer of ice up to kilometre deep, or by enormous glacial lakes. Certainly in northern parts, there was no vegetation as glaciers scraped their way across the landscape. So much water was locked up in the glaciers that sea levels dropped dramatically; we were connected to Europe by areas such as Doggerland. Details of the glaciation and its effect can be found on the BRITICE site. When the ice age came to an end some eleven thousand years ago, plants, animals and humans migrated back to the previously frozen and inhospitable land. Over time, large forests and woodland areas developed. In the North, boreal forest grew up - represented today by the remaining Caledonian Forest. Further south, there was the wildwood (as described by Rackham and others). The wildwood was probably a complex and tangled mixture of different trees, with many of the trees either dead or dying through the effects of wind, fire (lightning strikes) and flooding. It would have offered a vast variety of habitats and niches for plants, insects and mammals. Read more...
Checking through my emails, I came across a link sent by a friend to one of the winter talks in the program offered by the Botanical Society of Scotland - specifically “The Scottish Uplands: how to revive a degraded landscape” by Dr Helen Armstrong. The talk was live-streamed but was also recorded and is available here.
Dr Armstrong spent 24 years at the Nature Conservancy Council, the Macaulay Land Use Research Institute, Scottish Natural Heritage and Forest Research carrying out research and advisory work.
The following is an attempt to summarise some of the key features of her informative and enlightening talk. Read more...
In terms of a ‘head count’ of tree species, Europe does not do well when compared to Asia or North America. There are approximately five hundred tree species scattered across Europe, whereas Asia and North America are home to some thousand species each. There is fossil evidence that tree species such as Liquadambar (Sweet Gums) and Liriodendron (Tulip tree) once lived here. So one might ask why did they disappear?
The answer may be due a combination of glaciation and topography. During the late Pliocene period, the global climate cooled and massive glaciers began to extend across the Earth’s surface. Glacial and interglacial periods followed in the Pleistocene or Quaternary Period; sometimes referred to as the Ice Age. As the glaciers moved relentlessly south, so plants (and animals) had to move Read more...
Atlantic oak woodland is often referred to as the Celtic Rainforest. It is characterised by lichen covered trees, together with a rich moss and liverwort flora. The environment is damp and humid, with streams and waterfalls contributing to this. These woodlands have evolved under the influence of the Gulf Stream, which helps keeps the area warm (and wet).
The difficult access and rugged terrain (in some areas) has helped to preserve these woodlands, plus they have not proved suitable for agriculture or ‘industrial forestry’. Consequently, in many areas, they have remained in their 'ancient state', going back to the last ice age. Their sessile oaks are very important for wildlife but as they are not always productive of good timber, they have often been left to grow to maturity. By the same token, Birch trees have relatively low timber value - which has been their salvation. Woodlands like this were more extensive in the past covering the Atlantic fringe of Western Europe from North West Scotland down to the South of Portugal. This type of woodland is rich in terms of biodiversity (primroses, violets, wild garlic, ferns and grasses) and some species are only to be found here and nowhere else in the world. Read more...
Each year, a variety of conifers are sold as Christmas trees, for example, the
- Norway Spruce Picea abies
- Silver Fir Abies alba
- Nordmann Fir Abies normanniana
- Scots Pine Pinus sylvestris
and in North America
- Douglas Fir Pseudotuga menziesii and
- Balsam Fir Abies balsamea.
Some ten to fifteen million years ago, Iceland supported forests and woodlands of Redwoods (Sequoia), Magnolia and Sassafras. The presence of such species suggests that at this time the climate was warm and temperate. Later, in the Pliocene period, evidence from pollen studies, suggest that Pines, Larch, Birch and Alder had come to dominate; species that are associated with Boreal Forest - so the climate had cooled considerably.
There then followed the glaciations of the Pleistocene (often simply referred to as the Ice Age) - a geological epoch which lasted from about 2,500,000 to 12,000 years ago. Glaciers marched across the surface of the Earth, but retreated in the warmer inter-glacial periods. 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...