HydroBASINS lev08 watershed · #2080036670
Bassin de Øysterelva
A watershed (drainage basin) is not a body of water — it is the land area where rainfall converges towards a single river that eventually reaches the sea (or an endorheic basin). Boundaries follow ridgelines.
Crosses 8 administrative regions : Flatanger, Mandalseid, Namsos, Osen, Roan +3
Sub-basin area
578,2km²
Upstream area
578,5km²
Discharge
26,12m³/s
Mean elev.
272m
Administrative coverage
8 dept-equivalent regions (GADM L2)
- 475.4 km²81.7% of basin
- 43.5 km²7.5% of basin
- 23.8 km²4.1% of basin
- 23.2 km²4.0% of basin
- 9.3 km²1.6% of basin
- 4.7 km²0.8% of basin
- 1.0 km²0.2% of basin
- 1.0 km²0.2% of basin
13 intersecting protected areas
Finnvolldalen-Esplingdalen
IUCN IaNature Reserve
51.23 km² overlap
Øyenskavlen og Tverrlimyran
IUCN Not ReportedEmerald Network
33.52 km² overlap
Øyenskavlen
IUCN IaNature Reserve
30.68 km² overlap
Ferjlia
IUCN IaNature Reserve
6.55 km² overlap
Tverrlimyran
IUCN IaNature Reserve
2.84 km² overlap
Heggdalslimyran
IUCN IaNature Reserve
1.71 km² overlap
Skogkjerringholet
IUCN IaNature Reserve
0.33 km² overlap
Åsmyra
IUCN IaNature Reserve
0.29 km² overlap
Åsmyra
IUCN Not ReportedEmerald Network
0.29 km² overlap
4 more protected areassorted by overlap area
Svartberget
IUCN IaNature Reserve
0.17 km² overlap
Åsnes
IUCN Not ReportedEmerald Network
0.09 km² overlap
Åsnes
IUCN IaNature Reserve
0.09 km² overlap
Olaengåsen
IUCN IaNature Reserve
0.06 km² overlap
Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.
Species present
2 950 distinct species · 24 172 observations
Source: GBIF Occurrence snapshot 2026-05-01.
Ecological tissue
Sample of 37 species (selected proportionally per kingdom among those with at least one documented interaction here) to keep the graph readable. Hover for details, click to explore the full ecosystem of a species.
ℹ️ The territory contains many more species than displayed and all their documented interactions: the graph is intentionally the structural skeleton (top-N species by composite local score, edges filtered by Serrano 2009 disparity filter α=0.2).
Indicateurs du tissu écologique
Tissu écologique de Bassin de Øysterelva : 25 espèces dont 3 patrimoniales (LR IUCN CR/EN/VU) reliées par 129 interactions GloBI sur 7 types (connectance 17.4%, filtre Serrano α=0.2). 14 bulles taxonomiques (cascade genre/famille GloBI, ≥3 espèces).
Comparaison sur la connectance du réseau local complet vs distribution nationale (toutes les communes françaises).
Hydroclimate (BasinATLAS lev08)
Mean T°
3,8°C
Annual rain
1 231mm
Moisture idx (CMI)
0,65
Runoff
1 368mm/an
PET
434mm
AET
414mm
Mean slope
8,9°
Water table
304cm
Forest
52%
Crops
0%
Urban
0%
Protected
15%
HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)