PROJECT DESCRIPTION
BACKGROUND
As elsewhere in Europe, in Croatia the invasive alien tree species Ailanthus altissima (Ailanthus or tree of heaven) is a severe threat to the biodiversity of species and habitats. Ailanthus is a fast-growing, ecologically dominant woody species, with extremely high reproduction and dispersal potential, and a strong negative impact on native plant communities and soil biota, due to competition, shading, and the production of the phytotoxin ailanthone. Ailanthus is present in all three Croatian biogeographic regions. In the Continental and Alpine regions, Ailanthus is mostly associated with anthropogenic habitats, but it is also spreading to some protected areas. In the Mediterranean region, the species has become a serious problem in National Parks and other protectedareas, including Natura 2000 habitat types. Most importantly, Ailanthus threatens a habitat type that occurs only in Croatia: Tufa cascades of karstic rivers of the Dinaric Alps (32A0). Tufa cascades were the principal reason why Krka was designated as a National Park (NP) in 1985, and is one of the two prime sites (with NP Plitvice lakes) for this habitat type in the EU. In addition, Ailanthus threatens open Mediterranean grasslands, such as the priority Natura 2000 habitat type Pseudo-steppe with grasses and annuals of the Thero-Brachypodietea (6220*). Ailanthus is also a threat to cultural heritage in Croatia because it spreads in historic city centers, where its roots endanger building and wall construction, including in the UNESCO heritage site the Old City of Dubrovnik.
OBJECTIVES
The objective of the LIFE CONTRA Ailanthus project is to develop a large-scale control programme for the alien invasive tree species Ailanthus altissima (tree of heaven) in Croatia, including regular monitoring, eradication and legislative measures.
Specifically, the project aims at:
Eradication of Ailanthus in targetedNatura 2000 sites;Prevention of further introductions and spread; andAdoption of a protocol and national legislation.
The project implements the Habitats Directive, by reducing threats to protected species and habitat types in Natura 2000 sites in Croatia, and the EU Biodiversity Strategy for 2030.
RESULTS
Expected results:
Conservation status directly improved for Natura 2000 habitats type 32A0 (Tufa cascades of karstic rivers of the Dinaric Alps) and other habitat types within the sirse podrucje NP Krka Natura 2000 site, due to Ailanthus removed from 209 ha, with total eradication on 45 ha, and for priority habitat type 6220* in the Natura 2000 site JI dio Peljesca, with Ailanthus removed from 4 ha;Mitigation of sources of future introductions and spread of Ailanthus in Natura 2000 sites JI dio Peljesca and sirse podrucje NP Krka: i) clearance of Ailanthus from areas alongside main roads which serve as corridors of spread (30 km of road inspected and cleared), and ii) decreased introductions due to Ailanthus no longer being used in horticulture, backed by enforcement of established legislative and awareness-raising actions among public and horticultural companies;The preservation of cultural heritage sites improved by the removal of Ailanthus trees in the UNESCO heritage site in Dubrovnik, and the historic cities of Skradin, Mali Ston, Ston, and Zuljana (about 50 large female trees with seeds removed and replaced with native tree species). In addition, Ston is adjacent to the Natura 2000 site JI dio Peljesca, so removal of about 10 000 shoots and trees addresses a major source of spread into Natura 2000 habitats;Increased capacity for Invasive Alien Species (IAS) control: 25 stakeholders trained in removal methods for invasive alien tree species, including public institutions, NGOs, educational institutions, road maintenance agencies, forestry, and horticultural companies;National protocol and legislative: establishment of best practice for Ailanthus removal and dissemination in the form of published National protocol, and preparation of Order on Taking Measures to Remove Ailanthus altissima;Established early detection and rapid response network: National Advisory Committee for IAS formed, with clear assignment of taxonomic groups, responsibilities, and feedback time frame defined for each expert, citizen participation in data collection increased by 25%, and 5 rapid response protocols developed for plant species from the Union list; and Raised public awareness and knowledge on Ailanthus and other IAS.
