Assessing escapes from short rotation plantations of the invasive tree species Robinia pseudoacacia L. in Mediterranean ecosystems: a study in central Italy

Abstract: Black locust (Robinia pseudoacacia L.) is a fast growing tree species native to temperate North America, and widely diffused and naturalized in Europe. It is one of the candidate species for establishing bioenergy plantations on marginal lands in temperate and sub-Mediterranean regions. This potential is in contrast to its well-known invasive habit, leading to a potential damage to plant biodiversity in many European countries. Advise against black locust plantation in regions where it is already invasive has been issued by several international reports, as well as the adoption of mitigation measures (e.g., “containment” buffer zones) to prevent the spread of the species into natural and semi-natural habitats. In the Mediterranean basin, however, no studies have been carried out aimed at quantifying the escape rate of black locust saplings from plantation stands and its recruitment into natural habitats, together with the effectiveness of a buffer zone in reducing the spread. In this study we investigated the spread of black locust along 35 transects surrounding three 20-year- old plantations and including three different land cover types: abandoned arable land, semi-natural woodland and a buffer zone (orchards) with a low degree of farming input. In addition, the effect of soil disturbance on seed propagation was investigated. Our results demonstrate that the density of black locust regeneration is strongly affected by the land cover, abandoned agricultural land being the most prone to black locust colonization. Contrastingly, the spread was minimal in the buffer zone and negligible in semi-natural woodland. During the investigated year, seed generative propagation was also negligible. The semi-natural woodland seems to resist well to black locust invasion, though further observations are needed to assess the consequences of stand harvesting disturbance as well, according to local standard forest management. Buffer zones seem to be very effective in controlling black locust invasion. Best management practices, with active farming inputs, are also discussed.

[1]  S. Dullinger,et al.  Climate change might drive the invasive tree Robinia pseudacacia into nature reserves and endangered habitats , 2010 .

[2]  Z. Keserű,et al.  The silviculture of black locust (Robinia pseudoacacia L.) in Hungary: a review. , 2011 .

[3]  D. H. Rose.  A Study of Delayed Germination in Economic Seeds , 1915, Botanical Gazette.

[4]  C. Böhm,et al.  Soil CO2 flux in an alley-cropping system composed of black locust and poplar trees, Germany , 2013, Agroforestry Systems.

[5]  Sara González-García,et al.  Comparative life cycle assessment of ethanol production from fast-growing wood crops (black locust, eucalyptus and poplar) , 2012 .

[6]  Optimal measurement strategies for aboveground tree biomass in agricultural landscapes , 2015, Agroforestry Systems.

[7]  E. Bedmar,et al.  Effects of soil biota from different ranges on Robinia invasion: acquiring mutualists and escaping pathogens. , 2011, Ecology.

[8]  K. Dixon,et al.  Post-fire germination: The effect of smoke on seeds of selected species from the central Mediterranean basin , 2006 .

[9]  D. Dickmann,et al.  Leaf area and biomass in mixed and pure plantations of sycamore and black locust in the Georgia Piedmont , 1985 .

[10]  L. Boring,et al.  THE ROLE OF BLACK LOCUST (ROBINIA PSEUDO- ACACIA) IN FOREST SUCCESSION , 1984 .

[11]  Aníbal Pauchard,et al.  Pinus contorta invasion in the Chilean Patagonia: local patterns in a global context , 2010, Biological Invasions.

[12]  E. Hadač,et al.  Notes on syntaxonomy of cultural forest communities , 1980, Folia Geobotanica et Phytotaxonomica.

[13]  Maurizio Sabatti,et al.  Nitrogen removal and its determinants in hybrid Populus clones for bioenergy plantations after two biennial rotations in two temperate sites in northern Italy , 2015 .

[14]  Stefan Hempel,et al.  Biological Flora of the British Isles: Robinia pseudoacacia , 2013 .

[15]  Sandra Lavorel,et al.  Using plant functional traits to understand the landscape distribution of multiple ecosystem services , 2011 .

[16]  G. Bazan,et al.  Downy-Oak Woods of Italy: Phytogeographical Remarks on a Controversial Taxonomic and Ecologic Issue , 2015 .

[17]  C. Giuliani,et al.  Forest plant diversity is threatened by Robinia pseudoacacia (black-locust) invasion , 2012, Biodiversity and Conservation.

[18]  T. Campagnaro,et al.  Plant species diversity in alien black locust stands: a paired comparison with native stands across a north-Mediterranean range expansion. , 2012 .

[19]  Patrizia Gasparini,et al.  Aboveground tree volume and phytomass prediction equations for forest species in Italy , 2011, European Journal of Forest Research.

[20]  Jiquan Chen,et al.  Large-scale effects of forest management in Mediterranean landscapes of Europe , 2013 .

[21]  M. Gordon,et al.  Regeneration of a transgenic woody legume (Robinia pseudoacacia L., black locust) and morphological alterations induced by Agrobacterium rhizogenes-mediated transformation , 1993 .

[22]  Gordon C. Tucker.  Robinia pseudoacacia L. , 2006 .

[23]  S. Zerbe,et al.  Traditional coppice forest management drives the invasion of Ailanthus altissima and Robinia pseudoacacia into deciduous forests , 2013 .

[24]  R. Willan.  A guide to forest seed handling with special reference to the tropics. , 1985 .

[25]  R. Kominami,et al.  Distribution and characteristics of the soil seed bank of the black locust (Robinia pseudoacacia) in a headwater basin in northern Japan , 2010, Landscape and Ecological Engineering.

[26]  J. Ditomaso,et al.  Nonnative Species and Bioenergy: Are We Cultivating the Next Invader? , 2008 .

[27]  R. Crosti,et al.  Use of a weed risk assessment for the Mediterranean region of Central Italy to prevent loss of functionality and biodiversity in agro-ecosystems , 2010, Biological Invasions.