With only a couple of weeks left of my Ecology, Conservation and Habitat Management course, it is the latter, Habitat Management that I have been reading up on recently and more specifically, it is Woodland Conservation Management that I have been particularly interested in.
Woodland is extremely rich in species, but unfortunately every single one cannot be individually managed. Certain groups of plants and animals however have become the main focal points for woodland conservation management, as they ultimately benefit many other species. Some of the main species may use a range of habitats for example, or may even be very rare and specialised, which are equally as important.
So what are these groups and management plans?
There are around 54 types of tree community today in ancient woodland, and most are genetically the direct descendants of the original trees that grew. Trees of the same type can be found in all areas of Britain, but no one individual tree will harbour all of the insect/lichen/bird/fauna species that are known to be associated with that type, or even the woodland it is in. This is due to climatic and geographical variations in different areas of Britain.
To maintain the variety of trees and therefore species that benefit from them, it is important that semi-natural tree communities are managed through natural regeneration (the growth of trees that develop from seeds that fall and germinate on site) and/or by planting new trees of local provenance.
Like the tree communities, ground flora varies greatly from one woodland to another due to location variations and actually tends to be more abundant and concentrated in ancient woodland than in newer woodland. However, the isolation of ancient woods, could in fact lead to the extinction of some plant and invertebrate species (particularly those with poor mobility), so it is important that such species are encouraged to colonise or re-colonise to avoid extinction from habitiat deterioration. Open spaces and development of young growth are both vital for certain species.
Epiphytic flora and fungi
Plants that grow harmlessly upon another plant and derive moisture and nutrients from the air, rain, and sometimes from debris are called epiphytes, and many mature trees in relatively unpolluted parts of Britain carry an interesting and huge array of epiphytic flora and fungi (including more than 70 species of lichens alone). Particularly in the west of the country, these epiphytes are very rich and resemble those that lived in the original forests.
Epiphytes need to be conserved with methods such as partial-cutting to ensure that the mature tree communities they grow on remain in particular woodland sites and continue to naturally regenerate.
There are several small mammals in British woodlands that are rare and thankfully protected, and one of these is the Dormouse. The Dormouse is an elusive nocturnal mammal which can be found mainly in woodlands in the southern counties of the UK. Over the last 100 years its distribution has declined and it is now extinct in 7 counties where it previously existed. This is mainly due to changes in woodland management and habitat fragmentation. They feed on a combination of plant materials including flowers, fruits and nuts as well as insects, so it is important to manage sites specifically for them or any other rare species. Good management will help increase numbers and make the site more ‘valuable’.
Management for small mammals must include the provision of nest-boxes, tracking and surveying, coppicing and the encouragement of mixed species in the woodland to ensure good food supplies.
Although birds are different to most other woodland groups in terms of being very mobile, woodlands still have to be managed to ensure a range of birds benefit. Some species prefer mature, native trees or depend on dense close-canopy scrub, whereas others are associated with replanted areas.
Woodland management for birds is therefore concentrated on maintaining a mixture of age classes, by reducing the amount of old habitat deterioration and creating new suitable habitats.
Butterflies and moths
Many woodland butterflies and moths inhabit areas of young growth where nectar sources and food-plants for their larvae can be found. There has been declines in several species for many years however, and this is due to many things including woods becoming isolated which in turn weakens the ability for colonisation, as well as a reduction in coppicing which would produce new growth.
Understanding the complex life cycles of butterflies and moths provides an insight into what they need from woodland habitats and could provide the answer to effective conservation. Each stage may require a different habitat, from sheltered, warm places to areas that are plentiful in food sources, so management must concentrate on providing nectar-rich areas and suitable habitat for egg-laying and larval development.
These animals depend on dead, decaying or living wood and fungi to survive, so it is important that areas of mature trees, or even individuals are maintained and protected, to avoid dead wood being removed which would ultimately reduce or destroy the specialised habitats of many saproxylic invertebrates, including beetles and flies. Populations of such species rely on old wood being in a specific condition, so it is vital at these sites that the continuity of prime wood and trees is considered.