Property:Monitoring surveys and results
Jump to navigation
Jump to search
This is a property of type Text.
W
Monitoring has been primarily based on personal observations. Family and friends involved in the project have reported positive changes, such as increased water variability and enhanced vegetation growth along the banks. The presence of indicator bird species is used to track the project's success, with hopes of attracting more wader species. So far, kingfishers, mallards, herons, and little egrets have been observed. +
R
Monitoring has included water quality testing, macroinvertebrate sampling, fixed point photography, questionnaires and ecological surveys. See individual entries for more details. +
W
Monitoring in late 2013 found 4 water bodies in the project area have been lifted to high status for fish. Electrofishing of Lugg and Arrow 2013 showed wide dispersal of salmon (except upper Lugg) including Curl, Hindwell, Pinsley and Knobley brooks. +
T
Monitoring is quite problematic, since the stream runs dry for about 3 to 4 months a year. +
C
Monitoring of aquatic vegetation, especially during the prolonged drought that central Texas has been experiencing, is important to understanding potential impacts to fountain darters. Bryophytes (mosses) hold high densities of fountain darters and can be abundant in select locations of the Comal system (e.g., Upper Spring Run upstream of Landa Lake and in the upper portion of Landa Lake). Bryophyte stands in Landa Lake remained relatively constant between 2011-2012 (Figure 2). Cabomba, another native plant with relatively high densities of fountain darters, has been increasing in coverage in Landa Lake, and by fall 2012 it had the highest coverage that has been observed over the course of the study (Figure 2). In contrast, the aquatic vegetation in the Old Channel exemplifies the interactions between native (''Lugwigia'') and non-native (''Hygrophila'') aquatic vegetation in the river. Over the past several years, Ludwigia has become sparse (filamentous algae is rarely present), while Hygrophila has come to dominate most of the reach (Figure 3). ''Hygrophila'' flourishes in the Old Channel, and has been crowding out native ''Ludwigia'' (which has higher fountain darter densities) over the last several years. Ludwigia declined over the course of 2012 and is near the lowest coverage observed over the past decade. Bryophytes significantly increased in coverage during 2012, a ten-fold increase to the highest coverage ever observed at the Old Channel Reach. Since high densities of fountain darters occupy bryophytes in the Comal River, this could mean increased populations of the endangered fish if bryophytes remain in the Old Channel Reach. Filamentous algae, which covered a significant portion of this reach in the past, were still absent from the reach in 2012. +
A
Monitoring of fish stocks are ongoing. +
R
Monitoring of fish, bed fauna, physical conditions of the watercourse and birds has been conducted before the project start to ensure there is background registrations available to compare with the monitoring after the project start that will take place in 2014. Nitrogen levels and habitat types are also to be monitored
Expected results: (1) New wetlands of 350 hectares, (2) reduction of nitrogen load to Odense Fjord of approx. 60 tonnes of nitrogen a year, a (3) re-meandered watercourse stretch of approx. 10 km of the Tiver Odense, (4) grazing agreements for 156 hectares along the river, (5) grazing agreements for approx. 51 hectares along the fjord, (6) management plans for coastal meadows along the fjord and management plans for areas along the river, (7) improvements in relation to favourable conservation status for Habitat species and Habitat nature types, (8) information boards, (9) observation tower for the public. +
H
Monitoring of nitrates and phosphates and surveying of wildlife on going. To be undertaken by Historic Royal Palace Staff, local conservation groups, volutneers, and local community trained by Thames21. +
T
Monitoring of public responses to the project has shown good support and understanding of the reasons for the works. Volunteer engagement has been of a high quality and helped immensely in realising the broader aims of the project.
Fixed point photography has demonstrated the quick recovery rate of new earthworks and features.
Aquatic and chemical water quality monitoring results are awaiting post project analysis. +
U
Monitoring of the shad was a key component for this project, it underpinned all the other work, informing the fish pass design, measures of success, public engagement, citizen science, and international knowledge exchange and collaboration.
Shad are a relatively poorly studied fish, this is because they have only limited commercial value, there is no aquaculture of them, they are relatively rare, and were notorious for being tricky to handle for scientific investigation. This project initially had to rely on the limited amount of published literature, much of which was from the similar American shad. As for the European shads there was even less, so the project quickly made links with the few European organisation interested in shad conservation and management, primarily in Portugal, France, Belgium and Ireland.
This project allowed probably the largest study into shad behaviour anywhere in Europe to this point. Most previous studies had looked at only specific components of shad lifecycle. This required a multi-discipline approach and many of the techniques used were novel or adapted from known techniques to the conditions of the river Severn.
Spawning Behaviour, Genetics & Environmental DNA:
One of the key outcomes of this project was to see an extension in the spawning area used by shad. The Severn Estuary Special Area of Conservation status report classed shad as in “unfavourable” condition due to the barriers to migration cutting off their historic spawning grounds, with distribution of spawning only about 20% of that historically used. Effectively the weirs at Powick on the river Teme and Diglis on the river Severn were the upper most limits of spawning migration.
Two studies were carried out which concluded that the habitat on the Teme and the river upstream of Stourport on the Severn remained largely unchanged from when shad last had free access back in the 19th Century. When these results were compared with the latest evidence on good spawning habitat it was concluded that if shad could reach this habitat, it would be highly suitable for the restoration of the species. It was also known that a large amount of the total shad run ends their upstream migration at either Powick or Diglis weirs, suggesting that there are fish motivated to continue their migration if possible.
In each year of the project, night-time spawning observations were made by staff of the project, citizen science volunteers and students. This revealed some unexpected results, which were later supported by the tracking data. That is the lower navigable river is widely used by shad for spawning, this goes against much of the scientific literature, although similar behaviour is also witnessed in Belgium and Ireland. What the project investigation could not show is the effectiveness of the spawning in this area as shad were effectively forced to use these areas because of the barriers to migration.
The most effective method of recording spawning activity turned out to be audio recording equipment (several types were trialled). These devices were left in suitable locations throughout the river and the recordings were then analysed after the event. This revealed that with all the fish passes open in 2022, shad spawning was recorded between each of them. This was a great result showing that once access was restored shad would use the newly opened habitat as expected. This result also supported the other independent monitoring provided by the tracking and eDNA results.
Genetics also played an important part of this project, with one PhD successfully completing their studies looking at hybridisations and developing a technique to collect eDNA samples to confirm the presence or absence of shad as they returned to the newly opened river sections.
Other studies have shown that the two species of shad (twaite and allis) readily hybridise if forced to use the same spawning areas. This has been seen elsewhere in Europe and proved to be the same on the river Severn with circa 30% of eggs sampled showing a significant degree of hybridisation. It will take years to see if this level declines as the two species are able to spatially diverge their spawning over subsequent generations as a long-term result of this project.
The development of the eDNA technique, with the water samples now able to be taken by citizen scientist has been pivotal in ground truthing some of the other monitoring. The results clearly showed the barriers at Powick and Diglis were significant, however like many things in nature it was not quite as clear cut. eDNA in 2018 showed that in higher flow conditions some shad can negotiate these barriers, particularly on the river Teme. Although DNA detection levels were considerably lower than those below these barriers suggesting it is only a fraction of the population that make it over. This is actually an encouraging result as it clearly showed that a proportion of the run would start the recolonisation of the newly opened area once the fish passes were constructed, as has been proved right.
Counts, Run Estimates & Citizen Science:
To measure the initial and long-term success of the project it was important to have some idea of the starting population. Historical records show that shad numbers going back over the centuries were once sufficient to support an important local and export fishery from the estuary all the way up to the Welsh borders which ceased immediately after the construction of the navigation weirs in the 1840’s. In recent times an assessment of the population has not routinely been undertaken.
Early in the project it became evident that shad could be observed running the notch in one of the lowest weirs at Upper Lode weir in Tewkesbury. Not only was this the perfect public engagement opportunity, but it also provided an opportunity to try a variety of monitoring techniques to quantify a run of shad that pass upstream of this structure. Techniques used included hydroacoustic, resistivity counters, direct observation and video recording.
These methods were evaluated against each other, and direct observation proved to be the best for the project in determining a relative inter year run estimate. It was also hugely popular with the dedicated citizen scientists who undertook most of the observations. The use of video recordings made available on the website allowed the general public, often many miles removed from the river, to engage in the project, helping us to further validate the data.
In all but the wet year of 2021 when the weir was submerged in flood water from extended periods a consistent run estimate has been produced in all years of the project. By using the acoustic tracking results, it has also been possible to scale this run estimate up to a whole river run to include the proportion of shad that complete their whole lifecycle downstream of this structure.
This whole river run estimate has already been put to valuable use for Habitats Directive reporting, production of Habitats Risk Assessments and in support of a sensitive Public Inquiry where the Environment Agency was the regulatory authority.
Diglis Fish Pass Viewing Gallery Cameras:
Opened in time for the 2021 shad run, the viewing gallery at Diglis provided the project with another opportunity to count shad further upriver as they recolonised habitat unlocked for the first time in 180 years. A series of cameras were set up to record fish movement through the viewing window as they passed upstream. The hours of data collected was primarily analysed for shad, producing a passage rate of shad upstream as well as giving us valuable information on temporal movements to help inform the public tours at this facility. In 2021, 623 shad successful passed upstream and in 2022 this increased to 759 individuals. It is the offspring of these individuals that will kick start the restoration of shad in the Severn when they return as adults after 4-5 years.
25 fish species have been recorded using the pass (up to Feb 2023) so the benefits for the wider ecosystem are clear to see. Counts of other species have been limited to the other Severn Estuary Special Area of Conservation species, particularly salmon and sea lamprey. This has been particularly useful for local fisheries managers.
Tagging & Tracking Shad
Acoustic tagging proved to be far more successful than ever hoped, and by the end of the project 331 shad had been successfully tagged, far exceeding any previous study of shad in Europe. This was made possible by the design and installation of a trap that fitted in the notch in Upper Lode weir.
These fish provide data on all aspects of the shads’ behaviour, including duration of freshwater spawning migration, behaviour and delay at barriers (upstream and downstream), run estimates, distribution, freshwater mortality, difference in behaviour of individual between years, seaward migration, migration through the Bristol Channel (in collaboration with Swansea University), and marine mortality.
PIT tags were fitted to all 545 shad. These tiny tags are detected by an energised external electrical field (PIT loop) which were placed in several notches of the Diglis fish pass to monitor migration through the pass for efficiency trials.
L
Monitoring of the site has revealed changes to the in-channel morphology following
several geomorphologically effective floods, recording sediment shoaling, riffle
development and an overall slowing of erosion of the bed and banks. Reconnected palaeo
features have been rejuvenated; reducing overall erosive forces in the previously confined
main channel. Improved floodplain connectivity and increased floodplain area have led to
more frequent inundation and the deposition of significant quantities of overbank fines. Wetter habitats are also developing across the floodplain. +
C
Monitoring of the tree establishment success rate will be carried out. +
W
Monitoring sought to determine the changes in fish densities against the improvements generated by habitat work through a sophisticated electro fishing regimen. Robert Luxton from Cardiff University carefully monitored the changes in bank side vegetation as a result of habitat work he is just about to publish his PhD on this work. Details of these are awaited at time of going to press. +
E
Monitoring surveys and results are expected to be published soon. +
O
Monitoring the effectiveness of the bunds and leaky dams by installing time lapse cameras.
Monitoring visitor numbers and gathering feedback from visitors to understand the benefits of the guided walks and how we could make improvements +
R
Monitoring was completed before works to detirmine where works should be focused.
Monitoring was also completed after the works to establish how successful the project had been.
At the very least periodic visits to the site should be made to help ensure grazing management is ideal for the conditions that develop. Repear photographs are recommended for the archive. Biological monitoring may be of limited value if pre-conditions have not been recorded. +
P
Monitoring work has been undertaken including sonde data collection, freshwater pearl mussel survey and electro-fishing. On the River Ehen Atlantic salmon are the preferred host fish for as part of the freshwater pearl mussel lifecycle.
Successful encystment occurred in August 2013 (27 salmon fry), August 2014 (76 salmon fry) and September 2015 (41 salmon fry). Levels of encystment, natural and artificial, were monitored from 2010 to 2016. In 2010 1 site was sampled and 34 out of 39 salmon showed signs of encystment; in 2013 5 sites were sampled and 24 out of 32 salmon were encysted; in 2014 8 sites were sampled and 25 out of 51 salmon were encysted; in 2015 7 sites were sampled and 15 out of 21 salmon showed encystment; and in 2016 7 sites were sampled and 18 out of 21 salmon were encysted. +
Monitoring work is ongoing and being completed by the Dee District Salmon Fishery Board (electro-fishing, temperature loggers, habitat survey) and the James Hutton Institute (fixed point photography of morphology sites).
At the morphology restoration sites, monitoring was limited to before and after surveys, although general habitat and electro-fishing work carried out by the DDSFB may pick up trends in the future.
Establishment of riparian tree cover however is slow, especially in upland areas: monitoring of these longer-term projects is often overlooked, as it can require significant resourcing. However, it is essential to demonstrate that the restoration work is having the desired effect, and in this case monitoring will help guide further tree planting projects.
On the Dee, the monitoring includes continual recording of the water temperature (every 15 minutes) at 20 sites within tree planting zones and at 20 control sites away from the tree planting. In the longer term, this will highlight the extent to which riparian shade can reduce the extreme summer temperatures. It is also expected (and hoped) that these trees will boost salmonid production and prevent further declines in juvenile fish densities that may otherwise arise from warming waters. Therefore, annual surveys of fish numbers, using electrofishing, are carried out at both tree planting and control sites. Increases in fish numbers, and the wider benefits to the river habitat, are also expected to benefit the local pearl mussel population over the long term. +
I
Monitoring work is ongoing and has been in progress since 2014. The National Trust are working closely with designating bodies including the Environment Agency and Natural England as well as with local education institutions including Sparsholt College, Hampshire and Southampton University to monitor the results of works completed since 2014.
Monitoring SSSI areas. +
R
Monitoring:
- vegetation dynamics and dynamics of the seed bank
- transport of seeds (wind, water)
- birds
- counting of hunting tables
- hydrology
The former agricultural fields have been restored as temporary marshes and Mediterranean grasslands. The three objectives pursued have been globally achieved
- Ecological: increase of the heritage interest of the site
- Sociological: development of hunting activities for the inhabitants of the nearby hamlet
- Scientific: progress of knowledge in ecology of restoration
Main results:
- reclamation of a wetland destroyed by cultivation activities in the middle of the 20th century
By:
- the development of target plant communities according to hydrological conditions
- the installation of protected but not targeted species +