Could the Roadside Shrines Be a Source of Alien Plant Introductions? The Example of the ‘Difunta Correa’ Shrine in Almería (Spain)

Abstract

Ornamental gardens are probably the most important source of invasive alien plants. However, the role of roadside shrines as a source of alien plant introductions remains unexplored. Herein, we are reporting the cultivated alien flora of a roadside shrine (devoted to the ‘Difunta Correa’) in south-eastern Spain, while making a prior assessment of the risk of spreading in the surroundings. In an area of less than 50 m2, up to 20 plant taxa were identified, with the vast majority of them being alien. Some of the observed alien taxa can be very problematic (e.g., Kalanchoe × houghtonii) and are even included in the Spanish catalogue of invasive species (such as Opuntia ficus-indica). Although the shrine is not affecting the local biodiversity yet (though a few taxa are showing the first signs of spread), it is located just 1 km away from a valuable protected area (included within the Natura 2000 network of the European Union and also recognized as a Ramsar site). Roadside shrines and similar places (e.g., memorials or calvaries) should be, thus, regarded as a potential source of alien plant introductions; thus, monitoring is recommended, particularly when close to protected areas.