Tree monocultures in biodiversity hotspots: impact of pine plantations on the mammal assemblages of the Atlantic Forest and the Flooded Grasslands and Savannas ecoregions of South America.

IEZZI, MARÍA EUGENIA; DE ANGELO, CARLOS; VARELA, DIEGO; CRUZ, MARÍA PAULA; CIRIGNOLI, SEBASTIÁN; DI BITETTI, MARIO

Jyväskylä

Congreso; 5th European Congress of Conservation Biology; 2018

Society for Conservation Biology

Large scale plantations of exotic trees (mostly Pinus and Eucalyptus) are replacing vast areas of native environments in South America, with still poorly known consequences on the local communities. This is particularly worrisome in endangered ecoregions of high biodiversity that contain endemic and endangered species. This study was aimed at assessing the effects of pine plantations on the mammal assemblages of NE Argentina, in an areas were plantations are rapidly increasing. We evaluated the effects of the native forest replacement by non-native pine (Pinus sp.) plantations on the composition of the assemblages of terrestrial mammals in two forest productive landscapes. In the first study area, of approximately 5,000 km2 and located in the endangered Atlantic Forest of N Misiones province, we deployed (between May 2013 and December 2014) 184 camera-trap stations in three different ?treatments?: 53 in continuous forest, 69 in forest fragments and 62 in tree plantations. In the second, of approximately 20,000 km2 and located in the vulnerable Flooded Grasslands and Savannas ecoregions of NE Corrientes province and S Misiones, we deployed (between May 2016 and March 2017) 234 camera-trap stations: 35 in grasslands without cattle, 54 in grasslands with cattle, 35 in forests without cattle, 19 in forests with cattle, 54 in pine plantations without cattle and 37 in plantations with cattle. Camera-traps stations (Reconyx HC500) were active for an average of 50 (Misiones) and 45 (Corrientes) days. We used NMDS and PERMANOVA based on a Bray-Curtis similarity matrix to assess the effect of the treatment, the structural complexity of the vegetation, the presence of cattle (in Corrientes) and several landscape variables (cost-distance to the continuous forest in Misiones, the percentage of different environments within different radiuses, and the cost of human access as a proxy for hunting pressure) on species composition. We obtained 4735 independent records of 34 species in Misiones and 4460 independent records of 34 species in Corrientes. Mean recording rate and richness were much lower in pine plantations than in natural environments in both landscapes. In both landscapes mammal composition was affected by treatment, the proportion of native environments in the landscape, and human access. In Misiones, the distance to the continuous forest also had a strong effect on the compositions of the assemblage. Different management practices (e.g. pruning and thinning), the presence-absence of cattle and landscape features can partially mitigate the negative effect of tree plantations on mammal assemblages. Large areas of native environments that function as population sources and forest fragments immersed in the matrix of plantations (in Misiones) are necessary to preserve the original native mammal assemblage at the landscape level. Promoting connectivity of the native environments and improving hunting controls will also mitigate negative impacts.