Property:Monitoring surveys and results
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T
Toce River: conservation of riparian habitats for breeding and migratory birds - LIFE02 NAT/IT/008572 +
The results of the monitoring survey started in 2003 revealed an increase of some bird species using the restored habitats as nesting, feeding and hunting (raptors) areas as a positive consequence of the interventions, especially in the lowland hay meadows and in the dry scrublands. +
R
The rewetting of the entire pond (3.2 hectares) is effective. The reconnection with the groundwater has been rapidly produced. Due to the slow response of the different compartments, some monitoring results are still unknown. +
P
The river has adopted a more naturalised channel, with braiding, gravel shoals, small islands and back waters forming over time. This increases the potential biodiversity of this reach, which was previously canalised and fast flowing, with vertical banks. The backwater channel and islands provide suitable habitat for riparian mammals, while the slower shallow waters of the new channel offer a refuge for spawning and juvenile fish. The original bankside willow and poplar trees were retained on the three islands to provide undisturbed habitat, and deadwood piles were created on the islands from other trees and scrub that were felled around the sludge lagoons to provide habitat for invertebrates and small mammals.
In accordance with the ongoing Wildlife Management Plan for the site, prepared by Cascade, the developer undertakes a regular maintenance schedule, mainly involving removing debris (particularly tyres) dumped upstream and which end up in the back channel. No formal monitoring and evaluation is undertaken although the site is inspected visually to check that the islands remain stable. +
B
The scheme was monitored for 10 years; mainly with regards to fauna (i.e. birds, invertebrates, plankton, fish), but also water and sediment quality. +
N
W
The site will be monitored by Belmont’s ecology volunteer group and will act as the backdrop to their free, nature-based education programme. We will also be working alongside Belmont to continue to capture and record the impacts of site to showcase effective partnership working, to deliver long-term benefits for the local area and beyond.
During the delivery of the project, we conducted daily reporting and assessments of our works and findings, to ensure we were continuing to align with the project objectives and meeting the requirements to protect and restore local biodiversity. This included ECoWs reports, fuel logs, vehicle and machine checks, a desk -based study and contamination report, alongside daily walk-throughs to identify any potential risks and issues. +
O
The stream is monitored every three years to check its compliance with WFD criteria. It is also routinely monitored for other purposes. +
B
The study on the initial status condition and post-work
monitoring were carried out in the framework of the
ISO 14001 certification, i.e. to determine compliance
with the ISO 14001 standard.
The study on the initial status condition was carried
out in the summer of 2011 and addressed the fish
and hydrobiological compartments. Electrofishing
was done in the main channel. Hydrobiological
monitoring implemented a protocol derived from the
IBGN (standardised biological index), without a final
score. Visual monitoring of changes on the site was
regularly carried out.
Post-work monitoring on the same compartments
was done in July 2012 and 2013, i.e. 6 months and
18 months respectively after the work.
Ecological monitoring will be pursued 2, 3, 5 and
10 years after the work to protect the river banks.
The results of the fishing campaign in 2012, one year
after the work, revealed a relatively low level of
hydrobiological quality and overall quality in terms
of fish. This may have been due to the recentness
of the work because the helophytes had not had
enough time to form sufficient cover and enable the
various organisms to colonise the site.
The monitoring in July 2013 showed improved results.
A greater number of alevins were present, signalling
progressive colonisation of the bank habitats. The
vegetation is now firmly implanted and growing
satisfactorily. Future monitoring work will indicate
whether this positive trend has continued.
In addition, significant colonisation by alder trees at
the foot of the bank was observed, which will require
monitoring to track the future development.
The objective of the work was not to restore significant
hydromorphological functioning, but to re-establish
the lateral continuity that had been lost due to the
presence of the metal sheet piles. During the monitoring
visits, signs of several passages by beavers were
noted, confirming the significant improvement in
transverse continuity.
Voies navigables de France plans to return to the
site to make minor repairs on the geotextile and to
replant helophytes where they did not develop well.
The VNF technical department is satisfied with the overall
results of the operation. The work done on the site
did not affect navigation. Bio-engineering techniques
for river-bank protection cost less than standard, civilworks
techniques. However, their use requires correct
identification of the pressures weighing on the work
site and adaptation of the selected solution to those
pressures. The subsequent maintenance work must
also be adapted to the selected vegetation.
VNF now plans to continue replacing certain civil
works with bio-engineering techniques in the sectors
where it is possible.
M
The success of the hydrological reconstruction was seen by the very rapid changes in the bird fauna. In the years
after the reconstruction, rare and valuable species of birds such as the Pied Avocet (Reeurvirostra avosetta),
Black-winged Stilt (Himantopus himantopus) and Mediterranean Gull (Larus melanoeephalus) appeared
in unprecedented numbers in the marsh system. A decelerating stabilisation process, during which bird
assemblages became more characteristic to stagnant waters, followed the initial re-colonisation, and species
less typical in Hortobágy marshes disappeared.
Today reed beds, interspersed with stands of Broad-leaved and Narrow-leaved Bulrush, Softstem Bulrush and
Common Clubrush, cover most of the marshes. The re-colonisation of the once extensive submersed vegetation
has been extremely fast and White Waterlily, Yellow Waterlily, Yellow Floating-heart, Water Chestnut and
Floating Fern cover increasingly larger areas.
The marshes see a limited number of fish, whereas the Grass Snake and European Pond Turtle are abundant.
Among mammals, the Eurasian Otter is worthy of mentioning, which lives in great numbers in the canals and
nearby fishponds.
The project achieved all its aims in spite of unsolved problems regarding land purchase and land swapping. Moreover, several targets were even exceeded:
Two ecological corridors were established by purchasing 11 ha arable land, restoring grasslands on 42 ha arable land and by extensive cultivation of 31 ha arable land;
Buffer zones were established in critical areas by restoring grasslands on 364 ha arable land on 135 parcels adjacent to marshes;
Grassland was restored on an additional 341 ha arable lands, which reduced the proportion of arable land within the protected area from 32% to 14%;
The restoration of two Natura 2000 priority habitat types was carried out on 747 ha, of which 93 ha was loess steppic grasslands (habitat 6250) and 654 ha was alkali steppe grasslands (habitat 1530);
59 ha of arable land were purchased for grassland restoration;
Two goose farms were eliminated from alkali steppes by purchasing 306 ha grasslands and by transforming the area to sheep- or cattle-grazing;
A grazing scheme was established, involving 18 farmers/farming companies on 2580 ha grasslands, which includes 820 ha grasslands not grazed before the project and newly restored grasslands depending on their conservation status;
Grazing on 400 ha was applied on four marshes and fire management was carried out on a 120 ha marsh in order to open up homogeneous reeds.
148 ha arable lands were cultivated extensively (without the use of chemicals) to enhance populations of small mammals and thus strengthen the food base for Annex I bird species.
In short, the project significantly contributed to the improvement of the conservation status of marshes and Pannonic grasslands in the Egyek-Pusztakócs region in Hungary.
Further information on the project can be found in the project's layman report (see "Read more" section).
E
The success of the restoration projects was evaluated on the basis of a multi-disciplinary monitoring.
Hydromorphology was evaluated on three restored sites using microhabitat survey and three indices of physical quality. For all sites, hydromorphology was significantly improved 10-20 months post-rehabilitation, through the diversification of flows (depth, substrate, water velocity) and the creation of habitats (e.g. fish shelters, spawning areas and woody debris). The most positive effects were observed for the most ambitious projects (meandering river channel and reconnecting remnant meander compared to habitat diversification).
Biological quality, based on macroinvertebrates and fish communities, has generally showed a status quo or a slight increase 10-20 months post-completion. As for hydromorphology, we might conclude that the most ambitious rehabilitation measures have resulted in the most positive effects. However, it would be prudent to await the results of the next monitoring surveys (4 years post-completion).
The geomorphological monitoring has focused on the effect of rehabilitation measures on river dynamic (bedload transport, bank erosion) and the effectiveness of spawning gravel rehabilitation. +
B
The success of the restoration projects was evaluated on the basis of a multi-disciplinary monitoring.
Hydromorphology was evaluated on five restored sites using microhabitat survey and three indices of physical quality. For all sites, hydromorphology was significantly improved 10-20 months post-rehabilitation, through the diversification of flows (depth, substrate, water velocity) and the creation of habitats (e.g. fish shelters, spawning areas and woody debris).
Biological quality, based on macroinvertebrates and fish communities, has generally showed a status quo or a slight increase 10-20 months post-completion. Nevertheless, ambitious rehabilitation measures such as weir removal and meanders restoration have resulted in the most positive effects, while less ambitious measures such as habitat diversification have led to more contrasted results. In addition, restoration of the longitudinal connectivity was beneficial for Grayling, designated as Natura 2000 species, and for eels, concerned with the Benelux convention.
The geomorphological monitoring has focused on the effect of barriers on sediment transport and the effectiveness of spawning gravel rehabilitation. +
R
The transformation of the Carshalton arm of the River Wandle is a flagship project for what is possible in an urban environment. With both water and habitat quality having been addressed through the four phases, this section of river has been fully rehabilitated resulting in a diverse and functioning headwater with successful trout recruitment for the first time in over 80 years; achieving the overall project aim and its objectives.
It has just been confirmed (July 2015) that this project has delivered all of the Mitigation Measures required to the enable the Carshalton waterbody to reach Good Ecological Potential.
Fish Data: The EA has a monitoring site for the Carshalton arm at Butter Hill, where much of the work has been carried out. This provides a good time series of fish, invertebrate and plant data.
Environment Agency electrofishing survey results show that there were no wild trout found in the area prior to 2006. Survey results from 2009 and 2011 find low numbers of trout, likely 2+ and 3+ individuals. However following works, in 2015 the story is much different with a Redd count of 10 (increased from 2 in 2012) providing evidence that suitable spawning habitat has been successfully increased. Excitingly, 67 0+ trout were found in the same survey site which shows that fish are not only spawning but successfully recruiting and that optimum juvenile habitat has been created.
EA monitoring shows that other fish species have benefitted from the restoration work. Numbers of bullhead increased from 10-99 in 2011 to 1000+ in 2015. Similarly, three-spined sticklebacks also increased from 100-999 in 2012 to 1000+ in 2015. +
T
The vegeatation was succesful in creating flow resistance and a backwater effect, although the relation between water level and discharge was not as expected. +
R
The water quality results showed that, in general, the Mangaraí River is affected by deteriorated water quality when it comes to nutrients (total phosphorus), especially during the dry season (April-September). The low quality is also indicated by the low levels of dissolved oxygen (DO) found in both the ReNaturalize and Reference sections. The second major finding was that despite the low DO content in one of the campaigns, the ReNaturalize stretch demonstrated higher DO.
The research also showed that for the water turbidity analyzed ever 15 days there were no significant differences between the three reaches sampled.
For the quality of the sediments collected during the seven campaigns, results suggested that the ReNaturalize stretch presented higher retention of nutrients and organic matter. However, there was no significant difference in the results of organic matter, nitrogen and total phosphorus.
The grain size analysis showed a trend towards the composition of thinner material in the ReNaturalize reach and greater diversification of the local sediemnt profile. This could be confirmed by the hydromorfological assessments through riverbed mapping that showed the significant increase of the heterogeneity of the riverbed after the installation of LW.
The quarterly data of the abundance of ichthyofauna monitored in the restored section point to the success of the technique with regard to the improvement of the fish populations (increased abundance aprox. 80%) in the restored reach. +
G
The weir is a clear barrier to fish migration: electric fishing data show an absence of Atlantic Salmon of any age class upstream, but presence of Salmon immediately downstream. +
R
The weir removal allows the reconnection of nine kilometers of waterways. The population composition has not changed after works: trout and sculpin remained the two species recorded. The 2004 monitoring shows a recolonization of upstream sector by trout fry. In 2009, the trout population increases and reaches its equilibrium level .
In 2004, the lotic area recreated is immediately recolonized by sculpins. In 2009, Sculpin populations decrease. The evolution of the population of sculpin deserves a monitoring programme and comparisons with nearby rivers.
The weir removal restores sediment transport. The vegetation naturally recolonize the environment and stabilize the banks.
A new weir deletion on the Dragne watershed is planned for 2011. +
The wetland scrape has created 0.8 hectares of priority habitat and expected to attract additional priority species.
Successfully created new habitats that will have an immediate ecological benefit to the overall biodiversity of the site. Interpretation boards placed along the public footpath adjacent to the site will help to inform the wider community about the habitats created and why this work is so important. +
B
The wetting frequency of the floodplain has significantly increased since the final phase of work. Anecdotal evidence for the fishing clubs supports increase Brown Trout numbers. +
R
The work is being monitored by volunteers of the Box Moor Trust and the Environment Agency. +
N
There are continuous improvements in breeding and cultivation of freshwater pearl mussels. The pioneering work of the University of Bergen's facility at Austevoll is a success that provides hope for both the mussels in Haukås and other endangered populations. Batches of mussels have been released back into the river with promising results. It is still too early to know for sure how the mussel habitat will work over time. The biological and water chemistry changes are being monitored.
Unfortunately, there has been recorded episodes of pollution of the river that have led to mussel death in recent years. For instance, in 2017 (Johnsen, G.H, S. Kålås & I. Wathne 2018. Status for elvemusling i Haukåsvassdraget 2017. Radgivende Biologer AS, rapport 2629, 34 sider, ISBN 978-82-8308-485-6.)
Litterature e.g.:
https://www.radgivende-biologer.no/wp-content/uploads/2019/06/2629.pdf +