HydroBASINS lev08 watershed · #2080020450
Bassin de Crasse de Nézer
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 2 administrative regions : Gironde, Landes
Sub-basin area
276,5km²
Upstream area
276,8km²
Discharge
4,35m³/s
Mean elev.
23m
Administrative coverage
2 dept-equivalent regions (GADM L2)
- 174.1 km²62.8% of basin
- 88.5 km²32.0% of basin
11 communes (GADM L5)Available for FRA, RWA
- La Teste-de-Buch116.79 km²66% commune
- Biscarrosse53.80 km²28% commune
- Gujan-Mestras38.94 km²76% commune
- Gastes14.05 km²32% commune
- Sainte-Eulalie-en-Born12.44 km²17% commune
- Arcachon8.28 km²100% commune
- Le Teich8.10 km²9% commune
- Mimizan5.81 km²5% commune
- Sanguinet2.44 km²2% commune
- Lège-Cap-Ferret1.99 km²2% commune
- Biganos0.03 km²0% commune
14 intersecting protected areas
Forêts dunaires de la Teste-de-Buch
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
39.98 km² overlap
Bassin D\'Arcachon
IUCN VMarine Nature Park
15.77 km² overlap
Bassin d'Arcachon et Cap Ferret
IUCN Not ReportedMarine Protected Area (OSPAR)
14.16 km² overlap
Bassin d'Arcachon et Cap Ferret
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
14.16 km² overlap
Bassin d'Arcachon et banc d'Arguin
IUCN Not ReportedSpecial Protection Area (Birds Directive)
14.16 km² overlap
Landes De Gascogne
IUCN VRegional Nature Park
7.81 km² overlap
Dunes modernes du littoral landais d'Arcachon à Mimizan Plage
IUCN Not ReportedSpecial Areas of Conservation (Habitats Directive)
7.35 km² overlap
Dune du pilat
IUCN IVLand acquired by Conservatoire du Littoral (national seaside and lakeside conservancy)
5.21 km² overlap
Ile aux oiseaux
IUCN IVLand acquired by Conservatoire du Littoral (national seaside and lakeside conservancy)
2.15 km² overlap
5 more protected areassorted by overlap area
Bassin d'Arcachon - Secteur du delta de la Leyre
IUCN Not ReportedWetland of International Importance (Ramsar Site)
1.82 km² overlap
Camicas - l\'eden
IUCN IVLand acquired by Conservatoire du Littoral (national seaside and lakeside conservancy)
1.63 km² overlap
Land acquired by Conservatoire du Littoral (national seaside and lakeside conservancy)
0.71 km² overlap
Banc D\'Arguin
IUCN IVNational Nature Reserve
0.06 km² overlap
Banc d'Arguin
IUCN Not ReportedMarine Protected Area (OSPAR)
0.00 km² overlap
Computed live · GADM 4.1 × HydroBASINS lev08 × WDPA · cached after first hit.
Species present
5 837 distinct species · 326 377 observations
Source: GBIF Occurrence snapshot 2026-05-01.
Ecological tissue
Sample of 34 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 Crasse de Nézer : 27 espèces dont 1 patrimoniale (LR IUCN CR/EN/VU) reliées par 55 interactions GloBI sur 6 types (connectance 9.2%, filtre Serrano α=0.2). 8 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°
13,0°C
Annual rain
1 125mm
Moisture idx (CMI)
0,18
Runoff
501mm/an
PET
919mm
AET
725mm
Mean slope
1,7°
Water table
83cm
Forest
61%
Crops
11%
Urban
19%
Protected
4%
HydroATLAS BasinATLAS v10 (Linke et al. 2019) · HydroBASINS lev08 (Lehner & Grill 2013)