In the immense expanse of paddy fields of the Pavese and Novara areas, a biological entity of extraordinary interest has survived, saved from the dangers of destruction that instead hit the nearby area of the Rogge Guida and Raina springs, which still retain considerable environmental values.
Sensitive to the solicitations of the scientific and environmental world, the Lombardy Region has established an oriented nature reserve in the central part of the area since 1984, entrusting its management to the Province of Pavia.
The Loja Swamp is located in Lomellina, between the municipalities of S. Angelo and Zeme Lomellina and represents a flooded forest relic with black Alder, once a widespread habitat in swampy depressions with still waters, in the sortuminous soils and in the lower fluvial terraces of the old waterways, throughout the area.
The dominant tree species is the black alder rarely associated with English oak, white poplar, white willow, willow, field maple, white hornbeam, pear and wild apple and some specimens of elm, a species decayed by graphiosis.
In the undergrowth among the most significant species the Hawthorn, the Hazel, the Blackthorn, the Sanguine, while the herbaceous vegetation has among the most important species the Salcerella, the Water Yarrow, the yellow iris, the Reed of the marsh, the Mazzasorda greater or Tifa, the Nannufaro and some species of Sedge.
The fauna includes about fifteen species of mammals including the Shrew, the Moscardino, the Weasel, the Polecat and the Nutria, rodent of South American origin which probably escaped some breeding.
The varied environment determines a truly extraordinary presence of birds, with species linked to running waters, woods and uncultivated or arable land. We report only some of them, from the Ardeidae to the Kingfisher, from the numerous Anatidae to the Cavaliere d'Italia, to the Canareccione, to the Moorhen, to the Greater Spotted Woodpecker.
The reptiles and amphibians are noted, among others, with the presence of the Grass Snake, the Snake, the Triton, the Frog of Lataste.
In the waters live the brook lamprey and the crayfish, while among the fish one can observe the Pike, the Tench, the Carp, the Rudd, the Bleak, the Common Cobite and the Masked Cobite.
Thousands of insect species, including the now rare Carabus clathratus.
The Pro Natura oasis extends over 10 hectares made up of the wood that develops along the outflow shaft of the Cavo Solero and Roggia Raia.