Control of invasive alien species to restore threatened habitats in inland wetlands of northern Tuscany
The general objective of SOS Tuscan Wetlands is to revert the current tendency of the drastic loss in biodiversity and naturalness of inland wetlands in northern Tuscany, as the result of the impacts of some invasive alien species leading in the latest years to the extinction or high rarefaction of several species of EC interest and to the disappearance of once abundant vegetal formation, such as waterlily formation and formation belonging to the habitat 3150, and now confined to few and small sites.
Such a general objective will be achieved by undetaking a number of specific objectives, as follows:
1) Local eradication of Coypu (Myocastor coypus) in the Lake of Sibolla and in the wetland of Poggioni (in the SCI-SPA “Bosco di Chiusi e Paduletta di Ramone”); subsequent rapid detection and periodical removal of reinvading individuals; intense control in Bosco di Chiusi and Paduletta di Ramone (particurarly subject to reinvasion events), with possible temporary annulment in population size and periodical control/removal of reinvading individuals.
2) Significant reduction of density or local eradication of the populations of the North-American invasive alien crayfish (Procambarus clarkii) in the Lake of Sibolla and in the wetlands of Poggioni.
3) Maintenance of the consequently increased enviromental quality and of the better conservation status of species and habitats under the threat of coypu and crayfish (e.g. the Ferruginous Duck Aythya nyroca, Ardeids nesting on the ground, Amphibia and Odonata) through economically – sustainable periodical interventions.
4) Completion of ongoing actions aimed at ameliorating water quality in the Lake of Sibolla (by phytodepuration).
5) Restoration, in the SCIs “Lago di Sibolla” and “Bosco di Chiusi – Paduletta di Ramone”, of heterogeneous wetland mosaics with habitats of EC interest (3150, 3160, 7150, 7210*) against the colonization by Amorpha fruticosa, a highly invasive plant occuring today in wide parts of the wetlands belts, which replaces native species, speeds up the process of filling-up and thus threatens its persistance and survival of associated species.
6) Restoration and widening of habitats of planitial forest, highly rare in Tuscany and in peninsular Italy (91E0* and 91F0), and of the adiacent woods of Quercus pubescent (91AA*).
7) Creation of a buffer zone to qualify and protect planitial forests (with the reduction of the edge effect) of SCI “Bosco di Chiusi e Paduletta di Ramone”.
8) Restoration and widening of the humid grasslands (6420 habitat) today subject to change (through filling-up and evolution of vegetation) or replaced in the past by poplar tree plantations.
9) Production of favourable condictions for vegetal and animal species associated with wetlands, through the creation of small ponds in the woods.
The action aimed at the local eradication or containment of Coypu (Myocastor coypus) will be carried out through their capture with cages-traps (follwing the guidelines of the former Istituto Nazionale per la Fauna Selvatica, today ISPRA), which will be placed on the banks and in the areas of animals’ passage; the activity will be conducted by a local team who, after training and under the coordination of specialists, will progressively acquire knowledge and experience needed to guaratee the maintenance in loco of an autonomous and operational staff which will continue control activities after the conclusion of the project.
The action aimed at the local eradication/containment of invasive alien crayfish will be carried out following the Integrated Pest Management approach that will assure a higher probability of success through the use of more methods combined in accordance with the contest of application. In particular, the control techniques specially developed for P. clarkii will be applied; along with the traditional intensive trapping, they include techniques successfully used since times to control insect pests. The efficacy of these techniques, innovated for the control of crustacean decapods, has been already tested in recent field experiments. The strategy will be revised and adapted in function of the results of periodical monitoring. The action will be conducted by experts of the University of Florence and by a local team; the latter will be the trained and operative staff who will continue control activities beyond the conclusion of the project.
The control of alien and invasive plant species will be carried out through combined techniques, cutting and treatment with systemic herbicides following an approach already tested in other LIFE projects. Strips of sphagnum bog (3160) will be fenced in to avoid trampling and damaging by ungulates (wild boars). The renaturalization and widening of planitial woods will be accomplished through the thinning of the poplar grove and subsequent reforestation with species typical of the habitat. This will have the effect to increase the necromass available to the saproxylic fauna to the benefit of the entire forest ecosystem.
The intensive control of the alien Robinia pseudoacacia and the implantation of accessory species typical of the habitat will ameliorate the strips of white oak (91AA*), whose extent will be widened by cutting eucalyptus and planting Quercus pubescens s.l. and accessory plants typical of the habitat. Digging, morphological reshaping and control of invasive plants will be conducted to ameliorate humid grasslands (6420) subject today to change; in an instance, a controlled culvert on an adjacent canal will be constructed with the aim of restoring the pristine humidity of the soil; a poplar tree plantation will be replaced by pristine humid grassland, thruogh the cutting of trees and the control of alien and invasive plants. To favour aquatic species (both plants and animals), will be realized small humid zones in woods, through digging, banking and subsequent fencing to prevent damage by wild boars. A plant of phytodepuration system for the treatment of sewage of a small village in the proximity of the Lake of Sibolla will be accomplished by building an artificial little deep basin, fed with macrophytes and all the needed pipes and tubes.
Local eradication of coypu (Myocastor coypus) in the Lake of Sibolla and in the wetland of Poggioni (in the SCI “Bosco di Chiusi e Paduletta di Ramone”); subsequent interception or detection and quick removal of reinvading individuals; control of the coypu population size , leading to a minimal reduction of 80%, in Bosco di Chiusi – Paduletta di Ramone (the remaining part of the SCI) and possible temporary annulment in their occurence; subsequent detection and periodical removal of re-colonizing individuals; progressive reduction in the frequency of incursions.
Minimal reduction by 60% (in the first year) in the occurence of invasive alien crayfish in the areas of intervention (as assessed through the CPUE index, e.g. the number of crayfish captured per trap per day); higher reduction in the following years.
Amelioration in the conservation status of the species threatened by coypu and crayfish (e.g. Aythya nyroca, gruond-nesting herons, Amphibia, Odonata).
Restoration of approx. 15 ha in SCIs “Lago di Sibolla” and “Bosco di Chiusi e Paduletta di Ramone”, of heterogeneous marshlands characterized by the habitat 3150 “Natural euthrophic lakes with Magnopotamion or Hydrocharition-type vegetation”, 3160 “Natural dystrophic lakes and ponds”, 7150 “Depressions on peat substrates of the Rhynchosporion”, 7210* “Calcareous fens with Cladium mariscus and species of the Caricion davallianae”, currently invaded by the alien Amorpha fruticosa (which speeds up the phenomena of filling-up and its progressive disappearance) and degraded due to the impacts by the coypu and the North-American crayfish.
Amelioration of the conservation status of plant species associated with these rare environments (e.g. Aldrovanda vesiculosa), creation of suitable condition for the reintroduction (spontaneous or driven) of lost species of Community interest (Caldesia parnassifolia and Marsilea quadrifolia) and of other critically threatened species.
Requalification of about 26 ha (within the three SCIs) of planitial forests belonging to the habitat 91F0 “Riparian mixed forests of Quercus robur, Ulmus laevis and Ulmus minor, Fraxinus excelsior or Fraxinus angustifolia, along the great rivers (Ulmenion minoris)” and 91E0* “Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae)”. Requalification and widening of the habitat 91AA* “Eastern white oak woods”, for a total of 2 ha in the SCI “Lago di Sibolla”. Restoration of 9,4 ha (within the three SCIs) of wet grasslands belonging to the habitat 6420 “Mediterranean tall humid herb grasslands of the Molinio-Holoschoenion”, and consequent improvement in the conservation status of Gladiolus palustris. Increase in the population of Italian crested newt Triturus carnifex and of other species associated with wetlands, through the creation of small wet areas in wooded narrow valleys. Protection and requalification of three sites, of known four, corresponding to around 50% of the whole coverage, of Sphagnum bogs in SCI/SPA “Bosco di Chiusi e Paduletta di Ramone” and creation of optimal condition for their further development.
Treatment of sewage from a village in the proximity of the Lake of Sibolla (15-20 inhabitants) as a contribution to the increase in the quality of the Lake’s water.
Maintenance in loco of a trained and operative staff for the prosecution of the control of coypu and North-American crayfish after the conclusion of the project. Increase in the acceptance of the intervention against animal alien species by local people, associations and other stakeholders, with the consequent increase in the potential of undertaking other similar actions in the future to fight invasive alien species.