It has a great variety of habitats, including damp hay meadows, sedge fen, reed bed, scrub and wet woodland.

Magor Marsh Nature Reserve is the richest site in Wales for wetland beetles and soldier-flies, and its pattern of drainage ditches and other features have remained unchanged since the 14th century.

In the pond are water rail, coot, grey heron, little grebe, moorhen, little egret, Eurasian teal, shoveler and kingfisher.

[2] In the reen the most common species are grass snake, great silver beetle, smooth newt and otter.

In 2019 leaf mines and a larva of the marbled marble (Celypha woodiana) was found on mistletoe (Viscum album), this Biodiversity Action Plan (UK BAP) species has a limited distribution in Britain and the 2019 record was the first confirmed for Wales.