Location
The refuge is located in the eastern part of Wielkopolska and it encompasses a part of Srodkowa Warta river valley with a surface of 26971.2 ha. Warta river flows here parallelly in Warszawsko-Berlinska ice-marginal valley formed during the last glaciation.

Landscape
Flood terrace of Warta river is 4-kilometers-wide in some places and it is characterised by vast diversity of vegetation, what goes with creating great habitats for many species of animals, especially birds. Present bottom of the valley was made mainly in a result of accumulation and erosion of river's waters. The relief of the area is rich in different fluvial forms: riverbed banks, flood terrace with oxbows different types, dune terrace and dune hills. Flood zone still encompasses the majority of refuge's area creating temporary backwaters on even several thousand hektares. There are also interesting transition mires in septic hollows on dune terrace area. The vegeteation of the refuge is very diverse.

Ecosystem
The area encompasses at leats 24 types of habitats mentioned in Appendix I of Habitat Directive and some from outside of this list. They are exeptionally diverse (from boggy and fen, to dry and dune), and some of them remain in a very good state like priority inland halophilic meadows.

Relatively low level of antropogenic transformation decides about great natural value of the area. Ecosystems of natural and halfnatural character dominate here.

Habitats occuring on the area of the refuge:

• Species-rich Nardus grasslands, on siliceous substrates in mountain areas (and submountain areas, in Continental Europe),
• Natural euthrophic lakes with Magnopotamion or Hydrocharition-type vegetation,
• Molinia meadows on calcareous, peaty or clavey-silt-laden soils (Molinion caeruleae),
• Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae),
• Inland dunes with open Corynephorus and Agrostis grasslands
• Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco Brometalia)(*important orchid sites),
• Inland salt meadows,
• Hard oligo-mesotrophic waters with benthic vegetation of Chara spp.,
• Natural dystrophic lakes and ponds,
• Rivers with muddy banks with Chenopodion rubri p.p. and Bidention p.p. vegetation,
• European dry heaths,
• Hydrophilous tall herb fringe communities of plains and of the montane to alpine levels,
• Alluvial meadows of river valleys of the Cnidion dubii,
• Lowland hay meadows (Alopecurus pratensis, Sanguisorba officinalis),
• Calcareous fens with Cladium mariscus and species of the Caricion davallianae,
• Alkaline fens,
• Galio-Carpinetum oak-hornbeam forests,
• Old acidophilous oak woods with Quercus robur on sandy plains,
• Riparian mixed forest of Quercus robur, Ulmus laevis and Ulmus minor, Fraxinus excelsior or Fraxinus angustifolia along the great rivers (Ulmenion minoris),
• Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation,
• Transition mires and quaking bogs,
• Depressions on peat substrates of the Rhynchosporion,
• Bog woodland,
• Euro-Siberian steppic woods with Quercus spp.,
• Salicetum pentandro-cinereae,
• Large sedge beds,
• Alder swamp woods (Alnetea glutinosae).

Flora
Parts of swamp willow forests endangered with extinction in European scale, and also currant alder with ash-alder woods, and swamp ash-elm forests grow on this area. Swamp meadows and pastures and rushes have occupied the biggest areas for several hundreds of years. Sandy dunes are overgrown by grasslands and pine tree stands.

Flora of vascular plants amonts 1000 of speicies on that site, where about 100 are mentioned on regional red book of endangered species.

We can find here such species like: Pasqueflower (Pulsatilla patens), Angelica palustris, sand leek (Allium scorodoprasum), wild ginger (Asarum europaeum), hairy brome (Bromus racemosus), Carex bohemica, Cnidium dubium, lily of the valley (Convallaria majalis), early marsh-orchid (Dactylorhiza incarnata), spotted orchid (Dactylorhiza maculata), western marsh orchid (Dactylorhiza majalis), sand pink (Dianthus arenarius), deptford pink (Dianthus armeria), fringed pink (Dianthus superbus), ground cedar (Diphasiastrum complanatum), broadleaf hellborine (Epipactis helleborine), marsh hellborine (Epipactis palustris), great horsetail (Equisetum telmateia), marsh gentian (Gentiana pneumonanthe), dune gentian (Gentianella uliginosa), Gladiolus imbricatus, sea milkwort (Glaux maritima), Hierochloe australis, Siberian iris (Iris sibirica), marsh pea (Lathyrus palustris), European common twayblade (Listera ovata), marsh clubmoss (Lycopodiella inundata), stiff clubmoss (Lycopodium annotinum), stag's-horn clubmoss (Lycopodium clavatum), lesser loosestrife (Lythrum hyssopifolia), crested cow-wheat (Melampyrum cristatum), candid water-lily (Nymphaea candida), lax-flowered orchid (Orchis laxiflora), great broomrape (Orobanche major), greater butterfly-orchid (Platanthera chlorantha), common polypody (Polypodium vulgare), cowslip (Primula veris), wind flower (Pulsatilla pratensis), black currant (Ribes nigrum),seaside brookweed (Samolus valerandi), guelder-rose (Viburnum opulus), elatior iolet (Viola elatior) and Viola alpina.

Fauna
The area is valuable refuge for water and marshy birds. Nadwarcianski Landscape Park which is the part of Ostoja Nadwarcianska is qualified as the most valuable ornithologic area of Europe. The conditions and occurrence of specific biotopes create exceptionally favourable evironment for birds.

Like nowhere else you can meet here many endengered and extincting species: common kingfisher, tawny pipit, lesser spotted eagle, short-eared owl, great bittern, nightjar, whiskered and black tern, white and black stork, marsh, hen and Montagu's harrier, corn crake, Bewick's and wooper swan, middle spotted and black woodpecker, great egret, ortolan bunting, collared and red-breasted flycatcher, common crane, white-tailed eagle, little bittern, red-backed shrike, woodlark, bluethroat, smew, red and black kite, black-crowned night heron, honey buzzard, ruff, grey-headed woodpecker, Eurasian golden plover, little and spotted crake, little and common tern and barred warbler.

There are also numerous number of migrating birds: common sandpiper, pintail, shoveler, teal, wigeon, garganey, gadwall, greylag goose, house finch, white-winged tern, common quail, common cestrel, common snipe, black-tailed godwit, penduline tit, redshank, hoopoe and northern lapwing.

Also there is a rich amphibians' (stated 13 of 18 occuring in Poland) and reptilians' fauna: European fire-bellied toad, great crested newt, slow worm, common toad, common spadefoot, sand lizard, viviparous lizard, grass snake, natterjack toad, European green toad, European tree frog, smooth newt, European viper, pool, moor, marsh, common and edible frog.

Besides there are also beavers, otters and wolfs living on the area of the refuge.

Threats and Protection
Most of the area is included in the Nadwarciański Landscape Park (13 428 ha) and three Areas of Protected Landscape: Pyzdry (30 000 ha), Szwajcaria Żerkowska (4 885.1 ha) and Powidzko-Bieniszewski APL (27 541.9 ha).

The threats on the area of the refuge can be devided in two groups: interior - local and exterior - created outside the refuge and having effect on the vast areas. Threats inside the refuge are very diverse, however they usually have a smaller meaning. These are: illegal cutting trees and bushes, "wild" waste dumps and gravel-pits, sewage drops, succession of housing, poaching and unproper forestry. Whereas there are air pollutions and especially water pollutions in the rivers including to the second category (nowadays waters of Warta river in the borders of the refuge are unclassified, but there are signs of improvement).