A synthesis on the impact of non-native conifer plantations on ant and beetle diversity in north-western Patagonia

Abstract

Softwood forestry with non-native tree species is increasing worldwide and especially in many developing countries of the Southern Hemisphere. Tree plantations are beneficial in environmental and socioeconomic aspects, but at the same time there are recognised costs associated with afforestation. Our aim was to revise the existing information on the impact of exotic conifer plantations in north-western Patagonia on insect biodiversity. A total of five studies were selected and, in these, not every insect group responded in a similar manner to the habitat replacement. There was a tendency towards a reduction in abundance and species richness of several insects inside pine plantations. This change in abundance and richness was especially evident for ant assemblages and when pine plantations were dense. Beetle assemblages, in turn, showed diverse responses to the replacement of native vegetation with forests depending on the native habitat matrix. Our findings confirm that practices that reduce tree density (via thinning or during plantation) should be recommended to minimise their impact on insect biodiversity in north-western Patagonia. The consistent behaviour of ant assemblages, coupled with their abundance, ease to sample and unambiguous taxonomy make them reliable candidates for long-term monitoring of the impact conifer forestation in north-western Patagonia, as well as probably in other regions of the world in which non-native pines replace natural environments.

¿Es posible conservar la diversidad biológica y producir madera en las plantaciones de pino de la Patagonia argentina? Un estudio de caso

“…Estos bosques artificiales presentan efectos negativos directos e indirectos sobre la biota y el suelo, que están asociados básicamente a la tendencia a simplificar los patrones y procesos ecológicos de las comunidades naturales arbóreas y no arbóreas que reemplazan (Carnus et al 2006;Brockerhoff et al 2008;Paritsis and Ayzen 2008;Simberloff et al 2010;Lantschner et al 2011;Veldman et al 2015;Bond 2016;Braun et al 2017;Iezzi et al 2020;Rago 2021). Las plantaciones forestales pueden aumentar el riesgo de invasión biológica (Simberloff et al 2010;Corley et al 2018), los incendios (Bowman et al 2019), déficit de agua del suelo (Farley et al 2005;Filoso et al 2017;Bonnesoeur et al 2019) y la pérdida de diversidad biológica (Titeux et al 2017;Liu et al 2018;Lewis et al 2019).…”

“…Estudios previos previnieron sobre la necesidad ambiental de mantener rodales abiertos, debido a la correlación negativa que existe entre estas variables de cobertura y la diversidad de plantas (Paritsis and Aysen 2008;Dezzotti et al 2017Dezzotti et al , 2019, insectos (Corley et al 2006(Corley et al , 2018, aves (Lantschner et al 2008) y mamíferos (Lantschner et al 2011(Lantschner et al , 2012. El mantenimiento de una alta cobertura arbórea además aumenta el riesgo de incendios, ataque de plagas y erosión del suelo después de la cosecha (Schlichter and Laclau 1998;Gómez et al 2013;Ferrere et al 2015).…”