Responses of two sympatric sand lizards to exotic forestations in the coastal dunes of Argentina: some implications for conservation

STELLATELLI, O.A.; BLOCK C; VEGA L.E; CRUZ FB

WILDLIFE RESEARCH

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2015 vol. 41 p. 480 - 489

1035-3712

Context. Exotic forestations may modify habitat quality affecting native animal populations that require specific microhabitats to remain viable. Aims. We determine if abundances and body condition of the lizard species Liolaemus wiegmannii and L. multimaculatus differed between forested and non-forested dunes. We also examined what environmental attributes are important in explaining the potential differences. Methods. We sampled six sites of 300 ha each. Three of these sites had original vegetation and three were forested with exotic Acacia longifolia. We traced 120 transects per site searching for lizards. Key results. Lizards were two times more abundant in non-forested sites than in those sites covered by acacia trees (even as low as a fourth of the area). Sites with high densities of acacia (≥ 78% of coverage) had the lowest abundance of lizards. In forested sites the snoutvent length of L. wiegmannii was 10% smaller and relative body mass 22% lower with respect to non-forested sites. We found no differences in the body size of L. multimaculatus. Conclusion. The replacement of the native vegetation by A. longifolia has negative effects on lizard species representing a substantial threat to L. wiegmannii and particularly to L. multimaculatus, a threatened status species. Structural and thermal characteristics of the non-forested sites seemed to be more favorable for the abundance and body condition, whereas the dense vegetation and the low temperatures on the forested sites might explain the lower presence of lizards. Implications. We recommend that before the implementation of future forestation plans in the pampasic coastal dunes, the deleterious consequences that this practice generates on native lizard fauna must be considered. When necessary, we recommend that A. longifoliahas to be planted in a coverage that does not exceed a quarter of 48 the total area to prevent the formation of continuous (or closed) forests patches and to maintain the structural heterogeneity of the habitat that these lizards need to survive. In the most affected areas, eradication and control strategies may help to reduce the advance of this exotic plant over the areas intended for conservation.