Le foto e le analisi genetiche sulle tracce non lasciano dubbi: la lontra è tornata in Ticino, in alta Val Leventina per la precisione. Lo conferma il Dipartimento del territorio. Dopo l’individuo maschio ritrovato morto nel 2013 a Prato Leventina (vittima di un investimento), questa è la seconda testimonianza, dopo la sua estinzione, risalente agli anni ‘60.
La lontra della Leventina nell'immagine di una foto-trappola
Considerate le notevoli capacità migratorie della specie, gli esperti ritengono che le lontre notate in Ticino possano avere un legame con le osservazioni effettuate nella regione di Domleschg, nei Grigioni, oppure, anche se meno probabile, con la popolazione del Parco Naturale Valle del Ticino in Italia.
La lontra, originariamente, occupava gran parte dei maggiori corsi d’acqua svizzeri. In seguito alla caccia e al deterioramento del suo ambiente naturale è regredita progressivamente, a cavallo tra il XIX e il XX secolo.
Uno studio dell’Ufficio federale dell’ambiente nel 1990 concludeva che le cause concorrenti alla sua sparizione in Svizzera sono state la ridotta fecondità legata all’inquinamento da PCB, così come la correzione e lo sfruttamento dei corsi d’acqua e la banalizzazione degli habitat acquatici, che hanno avuto un impatto negativo anche sui popolamenti ittici. La specie è stata considerata estinta in Svizzera per decenni, per poi ricomparire sporadicamente in alcuni cantoni a partire dal 2009.
Red. MM/M. Ang.
Dal Quotidiano:
Dal Quotidiano:
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