GROSS.MAX at the AA

I missed the first Landscape Urbanism lecture by Eelco Hooftman at the AA but luckily they’ve put a video of it, and many other lectures, up on their website. Click the link below to watch it…

 http://www.aaschool.ac.uk/VIDEO/lecture.php?ID=1940 

...and here's the one by Martha Schwartz:

 http://www.aaschool.ac.uk//VIDEO/lecture.php?ID=1955

Eco Assignment 2

Think I'm going to choose Epping Forest for mine


View Larger Map

Actually, I'm going to narrow it down a bit and do this place nearby instead:

http://www.essexwt.org.uk/visitor_centres__nature_reserves/roding_valley_meadows/

UK forests 'under unprecedented threat from disease'

The EU plant health regime is no longer fit for purpose in preventing fatal plant diseases, says the Forestry Commission

The leaves of this ash tree show signs of ash dieback. Photograph: The Food and Environment Research Agency

The UK's forests are under "unprecedented threat" from foreign pests and diseases, according to the government department responsible for the protection of forests and woodlands.

The ash dieback fungus found in East Anglia last week is just the latest invader to pose a serious threat to UK trees, and government ecologists say that more than 3m larch trees as well as thousands of mature oaks and chestnuts have been felled in the past three years to prevent similar fatal plant diseases from spreading out of control.

"We are under an unprecedented level of threat from a range of exotic pests and diseases, a lot associated with the international trade in live plants," said the Forestry Commission. "There are protections in place but the EU plant health regime is no longer fit for purpose. Too many pests and diseases are still getting through."

More than 100,000 ash trees have already been felled to prevent the spread of ash dieback, or Chalara fraxinea, since the disease was identified in March.

But very many more larch trees have had to be cut down in the West Country, Wales and Scotland this year to prevent a plant disease caused by the Phytophthora ramorum pathogen from spreading. Known as "sudden oak death" in the US, it so far has not infected British oaks, but since its discovery in the wild in 2009 it has been found extensively in larch populations in south-west England, Wales and south-west Scotland, resulting in many of the trees being felled over a wide area.

"We now have six to eight organisms in the British Isles that are a real concern. In the 1960s and 70s it was Dutch elm disease, which killed 30m trees; in the 1990s it was a new Phytophthora which devastated alders along riverbanks. But in the last 10 years we have had as many new diseases as we had in the previous 40 or 50 years," said Joan Webber, principal pathologist at Forest Research, the Forestry Commission's research arm.

Plant experts are particularly concerned about the oak processionary moth, which arrived in west London in 2009 and has now developed two major populations. "It has the potential to spread anywhere there are oak trees. It is extending its range and has become established in the Netherlands and Belgium, possibly as a result of climate change and warmer winters," says the Forestry Commission.

Plant pathogens are on the rise globally and Britain is particularly susceptible because of its increasingly warm, wet winters and because it is a centre of world trade. Easy access to plants from around the world has encouraged gardeners to buy millions of exotic plants, many of which can arrive diseased. Some plants can only enter Britain with "passports", but the majority of diseases are only identifiable in laboratories.

The diseases and pests can arrive by several routes, say ecologists. In March, more than 250 live larvae of the Asian longhorn beetle, which can kill oak and willows, were found in trees in Kent. More than 2,000 trees had to be felled and burned. It was thought to have entered in wooden packaging for Chinese stone.

Dothistroma needle blight, which affects a range of conifer species, threatens commercial forests by significantly reducing timber yields. It has been found in all of the commission's forest districts in England and Scotland, and three out of four forest districts in Wales.

Tony Kirkham, head of the arboretum at Kew Gardens, which has 14,000 trees and has seen many attacked in the past few years, said some of the most serious threats came from the oak processionary moth. The caterpillars can cause serious defoliation and weaken oaks to the point where they are prone to other diseases.

Ash tree disease. Photograph: Graphic

Ash to ashes

1992 The fungus behind Ash dieback, Chalara fraxinea, emerges in Poland.

2009 The Horticultural Trades Association warns the government that the fungus, now widespread in Denmark, could spread to the UK, and calls for an import ban. The Department for the Environment, Food and Rural Affairs decides taking no action is appropriate.

2010 Disease confirmed in the Netherlands and Belgium.

February 2012 Infected trees detected in the UK for the first time, in a nursery in Buckinghamshire.

Summer 2012 Outbreaks of ash dieback identified at plantations and nurseries across England and Scotland, from County Durham to Berkshire.

October 2012 First cases in the wild identified in Norfolk and Suffolk. The government imposes an import ban.

guardian.co.uk

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South East Biodiversity Strategy for Saltmarshes

Coastal Saltmarsh

 What is it?

Coastal saltmarshes comprise the upper, vegetated portions of intertidal mudflats, lying approximately between mean high water neap tides and mean high water spring tides.

Saltmarshes are usually restricted to comparatively sheltered locations in five main situations:

• in estuaries
• in saline lagoons
• behind barrier islands
• at the heads of sea lochs
• on beach plains

The development of saltmarsh vegetation is dependent on the presence of intertidal mudflats. Saltmarsh vegetation consists of a limited number of halophytic (salt tolerant) species adapted to regular immersion by the tides. A natural saltmarsh system shows a clear zonation [does this word exist?] according to the frequency of inundation. At the lowest level, the pioneer glassworts Salicornia spp can withstand immersion by as many as 600 tides per year, while transitional species of the upper marsh can withstand only occasional inundation.

The communities of stabilised saltmarsh can be divided into species-poor low-mid marsh, and the more diverse communities of the mid-upper marsh. On traditionally grazed sites, saltmarsh vegetation is shorter and dominated by grasses. At the upper tidal limits, true saltmarsh communities are replaced by drift-line, swamp or transitional communities that can only withstand occasional inundation. Saltmarsh communities are additionally affected by differences in climate, the particle size of the sediment and, within estuaries, by decreasing salinity in the upper reaches.

Saltmarshes are an important resource for wading birds and wildfowl. They act as high tide refuges for birds feeding on adjacent mudflats, as breeding sites for waders, gulls and terns, and as a source of food for passerine birds, particularly in autumn and winter. In winter, grazed saltmarshes are used as feeding grounds by large flocks of wild ducks and geese.

Areas with high structural and plant diversity, particularly where freshwater seepages provide a transition from fresh to brackish conditions, are particularly important for invertebrates.

Saltmarshes also provide sheltered nursery sites for several species of fish.

Please see the UK BAP website or the BAP habitat definition for more information.

The situation in the South East 

Extent in England	app. 32,500 ha
Extent in the SE region	2,500 ha
Percentage UK resource in the SE	8%
Extent covered by SSSI designation	data to be added

Rate of Change

 It is estimated that 20% of the saltmarsh resource in Kent and Essex was lost between 1973 and 1988. The best available information suggests that saltmarshes in the UK are being lost to erosion at a rate of 100ha a year.

County	1998 extent (ha)	2008 extent (ha)
Berkshire	NA	NA
Buckinghamshire	NA	NA
Hampshire	2,660	data to be added
Isle of Wight	160	data to be added
Kent	1,390	datato be added
Oxfordshire	NA	NA
Surrey	NA	NA
Sussex	815	data to be added
Total	5,025	2,500

1998 data taken from 'The Biodiversity of South East England - An Audit and Assessment' published by the Wildlife Trusts of South East England and the RSPB, South East and Central Regions  

2008 data taken from regional or national BAP habitat inventory. Please note that some of the changes listed here are due to improvements in mapping and habitat definition. 

For the 2008 report on intertidal habitats please follow this link.

Current threats

The main threats to this habitat are:

• Land claim. Large-scale saltmarsh land claim schemes for agriculture are now rare. Piecemeal smaller scale land claim for industry, port facilities, transport infrastructure and waste disposal is still comparatively common, and marina development on saltmarsh sites occurs occasionally. Such developments usually affect the more botanically diverse upper marsh and landward transition zones.
• Erosion and 'coastal squeeze'. Erosion of the seaward edge of saltmarshes occurs widely in the high-energy locations of the larger estuaries as a result of coastal processes.
• Accretion. Accretion and development of saltmarsh is occurring on parts of the British coastline, notably in North West England where sediments are comparatively coarse and isostatic uplift largely negates sea level rise. However, this accretion is not sufficient to offset the national net loss of saltmarsh, and in many cases the newly created habitats differ from those being lost due to regional differences.
• Sediment dynamics. Local sediment budgets may be affected by coast protection works, or by changes in estuary morphology caused by land claim, dredging of shipping channels and the impacts of flood defence works over the years.
• Cord grass. The small cordgrass, Spartina maritima, is the only species of cordgrass native to Great Britain. The smooth cordgrass, S. alterniflora, is a naturalised alien that was introduced to the UK in the 1820s. This introduction led to its subsequent crossing with S. maritima resulting in both a sterile hybrid, Townsend?s cordgrass S.townsendii, and a fertile hybrid, commoncordgrass S. anglica. The latter readily colonises mudflats and has spread around the coast. It has also been extensively planted to aid stabilisation of mudflats and as a prelude to land-claim. Common cordgrass often produces extensive monoculture swards of much less intrinsic value to wildlife, and in many areas is considered to be a threat to bird feeding grounds on mudflats. As a result, attempts have been made to control it at several locations, although in some areas it is undergoing dieback for reasons not fully understood.
• Grazing. Grazing has a marked effect on the structure and composition of saltmarsh vegetation by reducing the height of the vegetation and the diversity of plant and invertebrate species. Intensive grazing creates a sward attractive to wintering and passage wildfowl and waders, while less intense grazing produces a tussocky structure which favours breeding waders. In recent decades, some grazed saltmarshes have been abandoned, leading to domination of the mid to upper marsh by rank grasses. Intensive grazing is considered to be a problem in some areas.
• Other human influences. Saltmarshes are affected by a range of other human influences including waste tipping, pollution, drowning by barrage construction, and military activity. Turf cutting is a traditional activity in some areas. Oil pollution can potentially destroy saltmarsh vegetation and while it usually recovers, sediment may be lost during the period of die-back. The effects of recreational pressure are not well understood but may be locally significant. Agricultural improvement (re-seeding and draining) has affected the upper edge and transition zones of some saltmarshes in the past and may still occur on a small scale. Eutrophication due to sewage effluent and agricultural fertiliser run-off has caused local problems of algal growth on saltmarshes.

Vision for coastal saltmarsh

The South East Biodiversity Forum’s vision for this habitat is that there should be:

• No further loss of existing habitat
• Good management, including visitor management, on all extant sites
• No damage to site integrity from activities arising outside the sites, eg. inadequately managed public access
• Re-creation of sand dunes on appropriate sites to restore some past losses, including the linking up of fragmented sites
• Greater public appreciation of sand dunes and their specialist wildlife, including greater awareness of the impacts of human pressures, such as dog-walking, mountain-biking, dumping of waste
• Creation of alternative green space around important sand dunes under pressure for increasing new housing

How we can deliver this vision

•  MoD Integrated Land Management Plans (www.defence-estates.mod.uk/conservation/2_biodiversity.php)
• Provision of land management advice by statutory (Natural England) and non-statutory agencies (NGOs)
• Agreements under Higher Level Stewardship
• Project funding (SITA Trust, WREN etc)
• Site management plans
• Minerals after-use (http://www.afterminerals.com/)
• Land purchase/management agreements by NGOs
• River restoration linked to Water Framework Directive Programme of measures
• Catchment Sensitive Farming tackling diffuse pollution issue

Original article - Coastal Saltmarsh · Habitat & Species · South East England Biodiversity Forum