Hollow Moor is one of the largest continuous areas of species-rich unimproved grassland in Devon, and comprises a mosaic of rush pasture, fen meadow and mire communities. Collectively these are known as Culm Grassland, a wildlife habitat which is becoming increasingly rare throughout western Britain. The site supports a diverse fauna and flora which includes both nationally scarce and locally important species.

The site is situated on the gentle slopes of a valley cut by the Wagaford Water. The grassland swards have developed on heavy acid clay soils derived from slates and shales of early Carboniferous age with impeded drainage.

The major part of Hollow Moor is dominated by rushes Juncus effusus and J .acutiflorus and purple moor-grass Molinia caerulea interspersed with short-cropped pasture characterised by such species as creeping bent Agrostis stolonifera, heath-grass Danthonia decumbens and a variety of sedges Carex spp. These plant communities include abundant meadow thistle Cirsium dissectum and devil’s-bit scabious Succisa pratensis. The uncommon lesser butterfly-orchid Platanthera bifolia, whorled caraway Carum verticillatum and the nationally-scarce wavy St John’s-wort Hypericum undulatum are present.

The site also includes the whole of Odham Moor lying to the north of Wagaford Water. This differs in character from Hollow Moor in having a greater abundanceof heath species, such as heather Calluna vulgaris, cross-leaved heath Erica tetralix and petty whin Genista anglica.

Willow Salix spp. and birch Betula spp. scrub is scattered throughout the site and oak Quercus spp. and hazel Corylus avellana woods occur along the stream edge,with alder Alnus glutinosa in the wetter parts. These add greatly to the importance of the site, providing habitat for a variety of butterflies including the nationally-scarce wood white Leptidea sinapis, rare in Devon, and the silver-washed fritillary Argynnis paphia. Other insects recorded on the site include the double line moth Mythimna turca, marsh fritillary butterfly Eurodryas aurinia and the hoverfly Orthonevra geniculata, all of which are nationally-scarce.

The site also supports a diverse breeding bird community including curlew Numenius arquata and grasshopper warbler Locustella naevia, and is much used by hunting barn owls Tyto alba.
Otters Lutra lutra use the Wagaford Water.