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Life Friuli Fens - Conservation and restoration of calcareous fens in Friuli

(1) Life Friuli Fens ©

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INTRODUCTION

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THREATS

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TARGETS

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ACTIONS
PREPARATORY ACTIONSspace
PURCHASE OF LANDspace
NON RECURRING MANAGEMENT, MOWINGS AND SCRUB-CLEARINGspace
NON RECURRING MANAGEMENT, ECOLOGICAL IMPROVEMENT OF WOODLANDSspace
NON RECURRING MANAGEMENT, RESTORATION OF NATURAL HABITATSspace
NON RECURRING MANAGEMENT, OPERATIONS ON WATER NETWORKspace
NON RECURRING MANAGEMENT, MICROHABITATS CREATIONspace
NON RECURRING MANAGEMENT, NURSERY IMPROVEMENTspace
RECURRING MANAGEMENTspace
PUBLIC AWARENESSspace
VEGETATION MONITORING
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LIFE FRIULI FENS

Vegetation monitoring

The project results need to be monitoring using the botanical-sociological method.

Appropriate observations will be carried out to estimate the vegetal communities diversity in the new recurring management subjected areas, and to verify the activities effects in the most important and endangered species.

Furthermore, in the restored habitats, the autoctonous species resettling trend will be estimated in comparison with the ruderal species population trend. In particular, the survivorship of specimens grown in nursery and transplanted in-situ will be monitored.

Monitoring will be continued with a study of the target species Armeria helodes and Erucastrum palustre; this study will focus particularly on the species that need an ex-situ cultivation and their reinstatement inthe environment.

Moreover, specimens and populations will be counted in order to analyse their functional relationships (metapopulations) and to reach a general preservation strategy for these endangered species.

 

Results

The monitoring present data collected during the growing seasons 2007, 2008, 2009, 2010 and 2011. These data allow to test both the performance of two populations of target species (Armeria helodes and Erucastrum palustre) and the management and recovery actions effects.
It is important to follow over the years the development of vegetation that depends both from the seeding and transplanting and the normal ecological dynamics. The early restoration stages are clearly dominated by the species - called "pioneer" - that show the best ability to re-colonize areas virtually empty.  Only later can be observed the entry and dominance of more demanding species that base their success on the environmental resources competition.

The considerations listed below are the result of the large number of surveys that have been carried out. 

 

During 2009 was found an Armeria helodes general increase, especially in areas subject to restoration but also in not managed areas. This observation is positive and lets hope for a slow but durable recovery.

Erucastrum palustre had a very large population of short duration in Gonars (over 1000 individuals) followed by a sharp decline in 2009. This significant decrease is due even to the missed mowing and to the rainy winter and spring. However the extraordinary resilience of this species should be considered because demonstrates its high flexibility and adaptability to changes even if it remains extremely localized. This was demonstrated by recent observation of two individuals in a Gonars fen that previously did not have this species. These individuals were observed after the recent non recurrent trimming. While overall the data is very negative, these "explosive" phenomena point to a certain ecological plasticity of this species and its ability to create very large populations in a short time. This behavior is very different from Armeria helodes that is much more conservative.

The amphibian species related to banks habitats - characterized by several annual species certainly more widespread in the past– are increased.

The planted species, especially Primula farinosa, act as seed-bearers and their populations are dramatically increasing. There has been a selection of some planted species because some of them – located in low positions and almost always submerged – died. The others had a particular bloom.

The ruderal species as Erigeron annuus are decreased because of flooding and timely management.

The good availability of water has help the colonization processes of Cladium mariscus in all restorations. This result is very significant because it demonstrates the success of the decortication actions. Those actions reached the oligotrophic gravel substrates that allow to this species to be very competitive against Phragmites australis and Typha latifoglia.

Schoenus nigricans is proving to be very competitive in all restorations with significant increase in coverage and occupation of empty spaces or occupied by small size species.

The non-recurrent and the recurrent managements allow significant improvements of the wetlands composition with a steady increase in the number of species and a greater coverage balance.

The cuttings are helping some orchids as Liparis loeselii.

The surface of amphibian habitats often characterized by annual species (eg Cyperus sp.pl. Samolus valerandi) or rare species (Anagallis tenella, Scirpus mucronatus, Typha laxmannii, Baldellia ranunculoides) are increased. These environments, that depends by water level fluctuations or by moderate human disturbance (tracks, banks clean up, etc..), are now very rare and their spread helps the growth of the overall biodiversity of these areas.

On the amphibian banks the development of biomass has led to significant movement of small size species as Anagallis tenella.

Some areas restored as "Magredo" with the use of flowers are showing excellent results in terms of turf grass consolidation and floral composition.

The decorticated area near Gonars demonstrated a fast natural development: while still in a composite situation there are all prerequisites for the formation of an alkaline fen and for Cladius fens.

The trimming actions, especially of Frangula alnus, take a long time and many repetitions. The annual sprouts are very vigorous and biomass is significant. The herbaceous layer readjustments and its progressive enrichment have also been seen where the summer cover of this species remain high.

The occurrence of rare species, along with a general increase in the biodiversity of these areas, points out that the seed bank remains active for a long time especially in conditions of peat soils. The deep change of the topsoil surface layers make hard to predict its potential.

Actions and restoration interventions create big surfaces of marginal habitat, amphibians and unstable, rich in specific flora, that need continuous "moderate disturbs" when the situation stabilizes and the competitive phenomena take over.

 

Among the Annex II species, two seem to be able to expand faster in restored areas:
• Euphrasia marchesettii appeared along the shores of Flambro lake among Schoenus nigricans cores. This species is annual and uses as strategy a large production of seeds that can be transported by several carriers and then reach new suitable habitats. In general this species shows a good growth capacity in suitable habitats and benefits by mowing work.
• Gladiolus palustris is a species extremely widespread in terms of populations and consistency. It occupies lots of habitats and then spreads up from Molinia meadows to Bromus grasslands. Its spread and its reproductive capacity  promote the expansion in new habitat stretches.


The good availability of water has only slowed the progressive production and the biomass accumulation as well as the felting which can be considered fens, Molinia meadows to Bromus grasslands auto-increasing phenomena. Thus it is observed a shift of species from Bromus grasslands to Molinia meadows and Molinia meadows to alkaline fens. This also becomes evident in some restorations where have settled both Molinion and Festuco-Brometea species. Only time will tell which contingent will impose itself.

 

Ruderal species are in decline even though their selective removal make hard their presence estimation. They are concentrated in low-water availability situations such as islets restorations or in Virco ruderalized meadows, where Erigeron annuus and Setaria pumila show a good consistency. Other annual species are in decline because they are related to the early recolonization stages and can not stand the competition phenomena.

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