Dyffrynnoedd Nedd a Mellte, a Moel Penderyn () is a 421.1

hectare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), that is, square metres (), and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. ...

biological and geological

Site of Special Scientific Interest A Site of Special Scientific Interest (SSSI) in Great Britain, or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland, is a conservation designation denoting a protected area in the United Kingdom and Isle ...

on the border of

Neath Port Talbot Neath Port Talbot () is a Principal areas of Wales, county borough in the South West Wales, south-west of Wales. Its principal towns are Neath, Port Talbot, Briton Ferry and Pontardawe. The county borough borders Bridgend County Borough and Rhon ...

and

Powys Powys ( , ) is a Principal areas of Wales, county and Preserved counties of Wales, preserved county in Wales. It borders Gwynedd, Denbighshire, and Wrexham County Borough, Wrexham to the north; the English Ceremonial counties of England, ceremo ...

Wales Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic ...

, notified in 1954. The name of the site means "The valleys of Nedd and Mellte and Moel Penderyn". This site includes the wooded valleys of the rivers Nedd and Mellte and their tributaries above

Pontneddfechan ; ; also known as Pontneathvaughan) is a village in Powys, Wales. It is the southernmost village in the historic county of Brecknockshire, within the Vale of Neath and in the community of Ystradfellte. It stands at the confluence of the rivers ...

as they pass through a

millstone grit Millstone Grit is any of a number of coarse-grained sandstones of Carboniferous age which occur in the British Isles. The name derives from its use in earlier times as a source of millstones for use principally in watermills. Geologists refer to ...

and

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

plateau, and the hill of

Moel Penderyn Moel Penderyn is a hill on the edge of Penderyn village, in the Brecon Beacons National Park in the county borough of Rhondda Cynon Taff Rhondda Cynon Taf (; RCT; also spelt as Rhondda Cynon Taff) is a county borough in the south-east of ...

, which lies to the east. The rivers have eroded deep, narrow valleys in the plateau, which lies some 300 m above sea level, with gorges, river cliffs, block scree, and waterfalls.

Biological interest

The site is of special biological interest for its extensive and diverse semi-natural woodland, important populations of several flowering plants and supporting outstanding assemblages of

mosses Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) '' sensu stricto''. Bryophyta ('' sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and ho ...

liverworts Liverworts are a group of non-vascular plant, non-vascular embryophyte, land plants forming the division Marchantiophyta (). They may also be referred to as hepatics. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in wh ...

and

lichens A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

. More than 600 species of plant have been recorded from the site, including a very large proportion of the

bryophyte Bryophytes () are a group of embryophyte, land plants (embryophytes), sometimes treated as a taxonomic Division (taxonomy), division referred to as Bryophyta ''Sensu#Common qualifiers, sensu lato'', that contains three groups of non-vascular pla ...

flora of mid and south Wales. It is the most southerly known locality in Britain for

Marsh Hawk's-beard ''Crepis paludosa'', the marsh hawk's-beard, is a European species of flowering plant in the tribe Cichorieae of the family Asteraceae. It is widespread across much of Europe with isolated populations in Iceland, the Ural Mountains, and the Cauca ...

(''Crepis paludosa'').

Geological interest

The site's geological interest lies in the range of geological features, well-exposed in the cliffs and rocky river beds. These include exposures at Moel Penderyn, Craig y Ddinas and Bwa Maen. The

geomorphological Geomorphology () is the scientific study of the origin and evolution of topography, topographic and bathymetry, bathymetric features generated by physical, chemical or biological processes operating at or near Earth#Surface, Earth's surface. Ge ...

features within parts of the valleys of the Hepste and Mellte are also of special interest.

Access

Large sections of the site are designated

open access land The freedom to roam, or everyone's right, every person's right or everyman's right, is the general public's right to access certain public or privately owned land, lakes, and rivers for recreation and exercise. The right is sometimes called the ...

. Other sections are accessible via public footpaths.

External links

References

Sites of Special Scientific Interest in Brecknock Sites of Special Scientific Interest in West Glamorgan Sites of Special Scientific Interest notified in 1954 Geography of Neath Port Talbot Fforest Fawr Vale of Neath {{UK-SSSI-stub