Variable retention as land sharing strategy to conserve arthropod diversity in forests and non-forest ecosystems of southern Patagonia, Argentina

MV LENCINAS; PL PERI; JM CELLINI; FJ SOLA; G MARTÍNEZ PASTUR

Bucarest

Conferencia; International Scientific Conference Forest Science for a Sustainable Forestry and Human Wellbeing in a Changing World; 2018

National Institute for Research and Development in Forestry

Variable retention is a silvicultural proposal to mitigate harmful effects of traditional harvesting practices on biodiversity of forests (Kohm and Franklin, 1997), and their benefits for several organisms have been reported worldwide (Lindenmayer et al., 2012). However, we suggest this approach could be useful not only for forests, but also for other ecosystem types. Here we presented some results that could justify their implementation as land sharing strategy in both forest and non-forest ecosystems of southern Patagonia (Argentina) to improve arthropod diversity conservation. We studied above-ground arthropod communities (mainly Coleoptera, Formicida, Solifuga) using pitfall traps in Nothofagus pumilio forests, Mulguraea tridens scrublands, and magellanic steppes. The studied forests were located in Tierra del Fuego Province, while the scrublands and the steppes were in Santa Cruz Province. In these forests and scrublands, retention approach had been implemented, therefore we studied aggregated and dispersed retention harvesting in forests (Martínez Pastur et al., 2009), and managed cut and retention strips in scrublands (Sola et al., 2016). On the other hand, we selected dry and humid steppe habitats; both impacted by livestock grazing. For all ecosystem types, control situations without harvesting neither grazing impacts were sampled as reference. Richness, abundance, occurrence frequency, Shannon-Wiener diversity and Pielou evenness indices, and similarity among assemblages were evaluated using univariate and multivariate statistical tests. In forests and scrublands, we found that retention approach (aggregates or strips) allowed the partial maintenance of arthropod community structure, preserving some of their characteristics more similar to natural and non-impacted ecosystems. On the other hand, dry and humid steppes presented significantly different arthropod assemblages, but grazing homogenized and resembles communities by loss of species, showing the need to implement strategies that mitigate impact, or exclude areas from livestock use. We conclude that land sharing could be implemented in forest and non-forest ecosystems to preserve arthropod communities, being the variable retention approach a good alternative for private or public lands. Likewise, legislation to promote conservation (like National Law 26331) could be not only generated for and implemented in forests, but also in non-forest ecosystems.