In today's world, ecosystems are threatened by the input of generally exotic alien species that
displace native species, causing ecosystem imbalance and biodiversity loss.

Referring to animal species, some of the measures taken once these species has been introduced
and its expansion has started, are detailed in the section of fauna monitoring and control. Besides,
there are other measures such as physical elimination (e.g. northern pike in rivers) and habitat
restoration and improvement (surely the most efficient measure in many cases).

In urban environments, the rock pigeon (Columba livia) may become a pest. In nature, serious
effects over native populations and the ecosystem due to American mink (Mustela vison),
mosquitofish (Gambusia holbrooki), zebra mussel (Dreissena polymorpha) and red swamp crayfish
(Procambarus clarkii) are well known.

Several exotic plants are invasive too: e.g. tree-of-heaven (Ailanthus altissima) or water hyacinth.

The knowledge of these species' ecological requirements is essential to controlling them, as habitat
restoration and management may repair and limit their expansion, since they frequently occupy
dimished habitats that don't represent a suitable habitat for native species yet, but paradoxically
reproduce exotic conditions in our own environment.

Liquen Consultoría Ambiental S.L. has specialists in land and water wildlife, whose interdisciplinary
knowledges produce a global view, suggesting specific solutions to every problem.