Reported costs of IAS in countries of the Mediterranean basin over the period 1990–2017. Subplots display (a) total costs (observed and potential costs), and (b) observed costs only. n = number of cost entries in expanded InvaCost database, B: Billions, M: Millions, K: Thousands. Circles highlight small-sized countries (Andorra, Gibraltar, Monaco, San Marino, Vatican City, all with no recorded cost). National borders are based on data from https://gadm.org/data.html and are for illustration purposes only. Cyprus is represented as a single geographical unit; all costs were from the Greek part. Map Projection: World Mercator.