Why biodiversity increases after variable retention harvesting: A meta-analysis for southern Patagonian forests

SOLER, R; SCHINDLER, S; LENCINAS, MV; PERI, P; MARTÍNEZ PASTUR, G

FOREST ECOLOGY AND MANAGEMENT

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 369 p. 161 - 169

0378-1127

Effects offorest harvesting on biodiversity can be varied and complex to understand. Weprovide a metaanalysis of 553 studies plants, insects and birds to identify thegeneral responses to Variable Retention harvesting (VR) 1?8 years post-harvestin Nothofagus pumilio forests of southern Patagonia. The analysis is focusedon: (i) richness and abundance, (ii) origin and habitat (native forest specialistspecies, native species of other habitats, alien species), and (iii) temporaltrends after harvesting. Our objective was to evaluate why biodiversityincreases after variable retention harvesting, by assessing the effects on (i)species richness and abundance in general, (ii) native forest specialists,native generalist species and alien species, and (iii) the recovery ofbiodiversity toward original conditions. Forests managed with VR supported higheroverall richness and abundance of plants, insects and birds in aggregate anddispersed retention than unmanaged stands, but with similar values each other.However, origin and habitat of species affected responses to VR. Aggregatessupport higher native forest specialist plant and lower plants of habitatsother than dispersed retention. However, both retention treatments increasedalien plants, although its richness and abundance was higher in dispersedretention. Native forest specialist insects were reduced in comparison tounmanaged forest, while insects of other habitats showed a positive response toboth aggregate and dispersed retention as well as did for bird species richnessand abundant compared to unmanaged forests. We found evidence for recovery oforiginal conditions for native forest specialist plants and insects, and plantsof other habitats. In contrast, alien plants and native insects of otherhabitats increased continuously in the studies included through thoserepresenting 8 years postharvest. Major differences among both retentionpatterns included significantly higher richness and abundance of alien plantsand native insects of other habitats in dispersed retention. Our synthesisshows recovery toward original conditions for some taxa, but demonstrateslong-term establishment of alien plants as well as insect species notassociated with native N. pumilio forests. These have emerged as a mainpotential threat to conservation of forests under VR prescription, at least atthe stand level. Retention forestry could play a fundamental role forconservation in productive temperate forests, but the influence of retentionpattern and aggregate size are still unclear.