How are our snakes and lizards doing?
Between 1994 and 2023, the population of seven species of reptiles (snakes and lizards) native to the Netherlands increased by an average of 30 percent. However, numbers have actually fallen over the past 12 years. The sand lizard population has declined the most in recent years, while the common wall lizard has increased significantly.
The Netherlands is home to seven species of reptiles. That includes three species of snakes (adder, grass snake and smooth snake), and four species of lizards (slow worm, viviparous lizard or common lizard, sand lizard and wall lizard). Their populations are calculated over the entire period (1994–2023), as well as over the past twelve years (2012–2023). This is important in order to keep a close eye on these reptilian species. If necessary, swift measures can then be taken to protect lizards or snakes.
| Jaar | Wall lizard (1995=100) | Sand lizard (1994=100) |
|---|---|---|
| 1994 | . | 100 |
| 1995 | 100 | 111 |
| 1996 | 118 | 123 |
| 1997 | 136 | 135 |
| 1998 | 155 | 148 |
| 1999 | 173 | 160 |
| 2000 | 189 | 172 |
| 2001 | 204 | 184 |
| 2002 | 214 | 194 |
| 2003 | 218 | 204 |
| 2004 | 220 | 212 |
| 2005 | 223 | 220 |
| 2006 | 225 | 226 |
| 2007 | 225 | 232 |
| 2008 | 230 | 238 |
| 2009 | 242 | 245 |
| 2010 | 258 | 254 |
| 2011 | 279 | 261 |
| 2012 | 308 | 264 |
| 2013 | 354 | 264 |
| 2014 | 415 | 261 |
| 2015 | 476 | 254 |
| 2016 | 530 | 242 |
| 2017 | 591 | 227 |
| 2018 | 655 | 211 |
| 2019 | 719 | 192 |
| 2020 | 782 | 173 |
| 2021 | 843 | 152 |
| 2022 | 902 | 133 |
| Source: NEM (RAVON, CBS) | ||
More wall lizards, but fewer sand lizards
The populations of three species of reptiles have increased since 1994. There are more wall lizards, in particular: nine times as many as in 1994. There are also more slow worms: three times as many as in 1994. However, after years of increasing in number, the population of sand lizards has actually decreased sharply over the past 12 years. Populations of the viviparous lizard and the adder have also declined over the past 12 years. Numbers of grass snakes and smooth snakes have fluctuated since 1994, but the trend has mainly been downward over the last 12 years.