Semi-natural grassland: area
The far-reaching changes in Dutch agriculture have resulted in a drastic reduction of the area of semi-natural grassland. Now, most of the semi-natural grasslands are endangered.
| Semi-natural grassland: area and risk status | |||||
| Type of grassland | Current area(ha) | Plant community(see Technical note) | Trend in area 1930-1974 |
Trend in area 1975-1998 |
Risk status |
| Calcareous grassland | 20 | a | sharp decrease | stable | critical |
| Dry grassland on inland sandy soils | 900 | b | decrease | decrease | endangered |
| c | stable | stable | safe | ||
| Nutrient-poor grassland on acid soils | 850 | d | sharp decrease | sharp decrease | critical |
| e | stable | decrease | susceptible | ||
| 30 | f | sharp decrease | decrease | endangered | |
| More or less closed swards on base-rich, rather nutrient-poor river dunes | 500 | g | sharp decrease | sharp decrease | critical |
| h | sharp decrease | decrease | critical | ||
| Moist or wet eutrophic grassland | 12000 | i | stable | increase | safe |
| j | stable | decrease | susceptible | ||
| k | decrease | decrease | susceptible | ||
| Permanent mesotrophic pasture | 6000 | l | decrease | decrease | safe |
| Permanent mesotrophic meadows | 3000 | m | increase | increase | safe |
| Fritillary grassland | 100 | n | sharp decrease | decrease | critical |
| Wet mesotrophic pastures and aftermath grazed meadows | 4000 | o | stable | stable | susceptible |
| p | decrease | stable | critical | ||
| q | sharp decrease | decrease | endangered | ||
| r | decrease | stable | susceptible | ||
| Wet nutrient-poor acid grassland | 3500 | s | decrease | stable | susceptible |
| Wet oligotrophic meadows | 30 | t | sharp decrease | decrease | endangered |
| Coastal herb-rich grassland on dry soils | 400 | u | decrease | stable | susceptible |
| v | decrease | decrease | critical | ||
| Dry dune grassland | 3500 | w | stable | stable | safe |
| x | decrease | stable | susceptible | ||
| y | decrease | decrease | endangered | ||
| z | decrease | decrease | endangered | ||
| aa | decrease | stable | endangered | ||
| Source: Van Opstal (1997); Weeda et al. (2002) | CBS/NC/Oct02 | ||||
Trends
In the 20th century much of the poorly productive grassland (semi-natural grassland) was converted to highly productive grassland. For example, compared with the situation in 1900, the current area of wet oligotrophic meadows is less than 0.1% and the current area of calcareous grassland is only 5%. The most important causes of the decline are fertilisation and the lowering of the groundwater level.
The greatest loss of semi-natural grassland was in the period from 1930 to 1975. Thereafter though the decline continued, it was slower. Of the 27 plant communities of semi-natural grassland that ecologists have identified in the Netherlands, only 5 are safe.
The semi-natural grasslands that remain are of little significance for agriculture; almost all are in nature reserves. Outside nature reserves, the plant communities of semi-natural grassland still occur on dikes and in roadside verges.
Technical note
The data on the present areas are from Van Opstal (1997); they are for the situation around 1996. The areas have been rounded off. Dune grassland has also been included in the table because this too used to be used for extensive agriculture. Saline grassland has been excluded from this overview, however.
The trends in area and the risk categories are derived from Weeda et al. (2002). The smaller the area and the more negative the trend, the more vulnerable the grassland type. The risk status categories are: safe, susceptible, endangered, critical.
As the grassland types recognised by Dutch vegetation scientists can comprise several plant communities that have different trends, the plant communities have been shown separately in the table, as vegetation associations (assoc.): (a) calcareous grassland; (b) bird's foot assoc.; (c) fescue and thyme assoc.; (d) marsh gentian and mat-grass assoc.; (e) heather bedstraw and fescue assoc.; (f) betony and tor grass assoc. (= grassland on dry slopes); (g) stonecrop and thyme assoc.; (h) sickle medic and downy oat-grass assoc.; (i) marsh foxtail assoc. (j) marsh arrowgrass and creeping bent assoc.; (k) strawberry clover and creeping bent assoc.; (l) crested dog's tail meadow; (m) false oat-grass assoc.; (n) snake's head fritillary assoc.; (o) ragged-robin and square-stalked St. John's wort assoc.; (p) green-winged orchid and yellow-rattle assoc.; (q) wild angelica and lesser pond-sedge assoc.; (r) buttercup and marsh ragwort assoc.; (s) sharp-flowered rush assoc.; (t) carnation sedge grassland; (u) sand catchfly assoc.; (v) kidney vetch and Nottingham catchfly assoc.; (w) Tortula ruraliformis & T. calcicolens assoc.; (x) dandelion dune assoc.; (y) grey hair-grass dune assoc.; (z) common bent assoc.; (aa) betony and tor grass assoc.
References
- Weeda, E.J., J.H.J. Schaminée en L. van Duuren (2002). Atlas van plantengemeenschappen in Nederland. Deel 2, graslanden, zomen en droge heiden. KNNV Uitgeverij. Utrecht.
- Opstal, A.J.M.F. van (1997). Ecosysteemvisie graslanden. Rapport IKC-Natuurbeheer. Wageningen.
