Protected & Rare Species in the Middle Level
IDB channels in the Middle Level are a stronghold for a range of protected, rare and threatened species. Our ecologists hold a number of protected species licences and are experienced and knowledgeable in the survey and mitigation for a wide range of other species that are commonly found within the Middle Level area. This helps to ensure IDBs can deliver the best outcomes for them through their work.
Our operatives and contractors receive regular training on a wide range of protected species as well as biodiversity enhancement approaches in general. They follow a suite of environmental Standard Operating Procedures aimed at maximising the outcomes for a wide range of species, both protected and not, during their everyday work. Non-routine work is assessed for its impact on a wide range of species but particularly protected species, and approaches are designed-in to ensure that work is not only compliant but enhances biodiversity too.
Conservation begins with understanding what you have in the first place. We undertake a huge number of surveys each year across the Middle Level area to understand what wildlife is thriving in channels in each location, protected, rare and common, and how our work is supporting biodiversity in general. This helps to inform our routine and non-routine work approaches. Some of these surveys are published on the IDB’s individual webpages and we post highlights in our news section so check back for regular updates.
Otters:
Our waters provide some of the best fishing in the country and our otters agree! We have many otters in the Middle Level area and we consider them in all that we do. They are quite shy and elusive so we retain dense marginal and bank-side vegetation wherever possible for them to shelter in. We give their favoured spots plenty of room when we are working such as dense scrub, fallen deadwood and tree roots. About 65 artificial otter holts have been built into Middle Level banks too.
Water Voles:
Populations of water voles have declined by 94% – 97% in the 20th century, due mainly to predation by American mink and partly to declining habitat quality. They are listed as endangered in Northern Ireland and England, critically endangered in Wales & near threatened in Scotland. However the waters of the Middle Level have remained a key stronghold for them so we work hard to conserve and enhance their populations. It is not often we survey banks now and don’t find them so we must carry on our good work to keep it this way. 
We have been actively involved in a project which aimed to control the main predator of water vole, the invasive American Mink. The project has been so successful that almost no mink have been caught in the last couple of years in the area. We hope this, in conjunction with our active and sensitive habitat management, will continue to provide high quality habitat for water vole and they will continue to thrive in our waters.
Sometimes there are water voles where we need to undertake work to maintain public health and safety, for example to fix a bank slip to prevent it from blocking a channel and causing a flood risk. We have licensed ecologists who can carefully move water voles out of the way, compliantly, to make sure they are not harmed by the work. This is an complex and lengthy process so this is only done where it is absolutely necessary and can only be done outside of the breeding and hibernating periods for water vole, from 15th Feb-15th April and between 15th Sept to 30th Oct. For more information on water vole displacements, see here: Water Vole – Myth Busting
Eels:
The Fens are an important refuge for the endangered European eel, which used to be so numerous that they were used to pay taxes! There has been a significant decrease in the number of eels reaching European river systems over the past 20 years. Over-fishing, pollution and fragmentation of watercourses by installation of structures are some factors that have contributed to their dramatic decline. As a result, the European eel is now listed as ‘critically endangered’ on the IUCN Red List.
We review all our in-channel structures regularly and when any significant refurbishment or replacement is required, if it would be a benefit to eels and fish, we install eel and fish passes and/or fish friendly pumps.
We only ever manage the centre 2/3rds of channel where possible during routine channel maintenance, such as desilting and aquatic plant management, to ensure that channel margins and marginal vegetation are retained as an undisturbed habitat for eels.
Barn Owls: Barn owl numbers decreased dramatically over the 20th century but numbers are now considered stable. Declines were blamed on a number of factors including habitat loss from agricultural intensification, and the loss of suitable nesting sites. The banks of our channels are a larder of small mammals for barn owls and the Fens are a known stronghold for the much loved species. We have worked in partnership with a number of amazing volunteers for many years to erect and maintain well over 100 barn owl boxes across the Middle Level area. Any chicks found in nest boxes are ringed so we can better understand population trends in our area.
2025 is not looking like a great breeding year so far for the species with very few chicks found to ring. But watch this space for updates through the summer and early autumn to see if the slow start takes a better turn.
We found some surprised kestrel chicks in one box and a couple of pairs cosying up in some other boxes so not all bad news!
Reptiles:
You can often see our native grass snakes basking in the sun on an MLC bank and we find plenty of lizards when we are combing the banks during surveys.
We leave plenty of dense vegetation in the channel margins and on the bank and patches of scrub wherever we can for reptiles. Our mowers are set at a high cutting height so that reptiles hiding at the base of vegetation can stay out of harms’ way. Piles of cut vegetation on banks and at pumping stations act as perfect incubators for reptile eggs and grass snakes can often be found soaking up the warmth of a pile of composting vegetation.
Breeding Birds:
The channel banks and margins are a vital refuge for so many birds, all of which are protected, particularly when they are breeding.
Our routine and non-routine works are adapted and designed to ensure compliance with all breeding bird legislation and to ensure that as much habitat as possible is made available for them.
- Bank-sides are not mown until later in the year to avoid the main bird nesting season and even then, areas that are least favourable for nesting birds are cut first, leaving the prime nesting areas until much later.
- Areas that have to be mown or cut short for health and safety reasons are often less favourable to most nesting birds, so these areas are kept to a minimum. This includes areas such as bank tops that are cut to make sure our tractor drivers can see the bank edges for their own safety. It also includes narrow strips of bankside vegetation that are kept short to allow our channel maintenance boats to tip cuttings onto the bank without the risk of damaging or disturbing nesting birds. These areas are cut from early in the year and kept short all the way through the nesting season to encourage birds to nest out of the way in adjacent reed and grasses, to protect them from harm.
- These sectional mowing approaches carry some other benefits; it helps to keep dominant plant species from taking over and allows some other less vigorous species a chance, giving a more diverse bank-side sward.
- Only when it is absolutely vital is work undertaken in the bird breeding season, and working areas are always surveyed for the presence of nesting birds prior to work commencing. Any area where nesting activity found or suspected has a no-go zone applied around it and is left well alone.
Badgers:
Badgers are not protected because their numbers declined, they are protected to prevent their persecution. Badgers are amazing creatures and while their burrowing can be challenging for flood risk management, we can and do successfully operate around them. They are very much part of our Fenland landscape and understandably, they often favour a remote raised bank with nearby dense vegetation as a place to dig their setts, away from the often soggy or cultivated surrounding flat land. Who wouldn’t!
We record and monitor the locations of all known badger setts within the Middle Level system. Our workforce hold badger licences to allow them to competently and sensitively carry out their routine operations around Badger Setts in line with licence conditions. When more intrusive work is needed around badger setts, we have licenced ecologists who can plan and oversee the work.
We so often get asked to close a sett or move badgers away from our ditches and banks, with people worried that they will cause damage, block or collapse banks and increase flood risk. But it’s not that easy. IDBs don’t have any special permission to control badgers because we are flood risk managers. Just as farmers, the public, or the Environment Agency don’t have either. It is an offence to disturb a badger in its sett or to damage a sett. The law requires that even if we have to move Badgers out of the way for public safety, we have to either build an alternative place for them to live, as close as possible to the original sett, or make sure one is already available for them to move into nearby. Closing badger setts is a big, lengthy and costly task, particularly when IDBs don’t own the surrounding land! So we only consider sett closures when absolutely necessary and when all other options have been explored. We will always try to monitor and maintain bank stability and keep channels clear in other compliant ways before considering closing a badger sett.
Trees and bats:
Where there are trees and water, there will be bats! This is why we are very careful when working around trees near our channels. Only if it is absolutely necessary do we cut back any mature bank-side trees and we favour pollarding over complete removal to try to retain as many potential roost features for bats and other creatures as possible. A survey by one of our trained ecologists is always required before any work takes place on bank-side trees within our control, to check for bat roosts and other species including nesting birds. Where any are found, a licenced ecologist will plan and oversee the work in the correct season. If we have to remove a tree where it may be damaging a bank or blocking our maintenance activities, we will always seek to plant at least one in return.
We have erected a huge number of bat boxes on trees and pumping stations across the Middle Level area to boost the number of roosting places for bats near channels. We are happy to provide more so if you have a good tree or building near an IDB watercourse and would like to help bats, please let us know.
We plant as many trees as we can to boost biodiversity across our system and have planted thousands in the last few decades. Trees and hedges have to be planted in the right place though so we think carefully to check if they are the most suitable habitat we can create in any particular location. Often, digging a new ditch or shallow pond may be a better solution where water tables are high and peat is present, or restoring a field to a flood plain grazing marsh would more relevant in the local landscape. Many say that drainage ditches are the inverted hedges of the fens and we often tend to agree! But otherwise we will always find a good spot for a new tree or hedge.
Plants and invertebrates:
The fens are a very unique landscape and home to a huge diversity of plants and habitat types. As a result we also have a very diverse and valuable range of invertebrates.
We have a “build it and they will come” attitude to our habitat management. We aim to maximise the volume and the diversity of channel and bank vegetation and encourage surrounding landowners to create diversity along riparian margins and fields, for example through environmental stewardship, creating high-quality wildlife habitat and corridors through the Fenland landscape.
Our routine channel management includes rotational cutting, which helps to control dominant species to give the less vigorous species room and opportunity to thrive, increasing overall diversity. It also retains a greater diversity of vegetation maturity. Maintaining areas of more mature vegetation benefits a number of invertebrates that complete their larval stage in mature reed stems and even reed warblers favour mature reed stems over the water for nest building.
Where opportunity arises through non-routine works, such as through bank repairs, we use a more diverse seed mix with some broadleaved flowering plants as well as grasses on our banks to support more invertebrates and pollinating species. The differing rooting structures of the plants help to bind the soil on the bank too, providing greater protection from soil erosion. We often install pre-planted coir roll with a number of marginal plant species in to enhance channel margins for a wide range of wildlife too.
Where we find that a diverse range of plants already exist, or some rare or notable plants are thriving, we assess and plan our management regime carefully to make sure that we maintain the conditions that have allowed them to thrive and encourage their spread. This way, we expect to be able to support a greater diversity of insects too.
While these flora and fauna are fascinating and beautiful in themselves, we also recognise that all these plants and insects form and support a vital part of the ecological lifecycles and food chains of many other creatures. Including ourselves. Invertebrates are responsible for pollinating crops and predating on crop pests. The greater the diversity of plants we can sustain in and around our IDB channels, ditches and field margins, the greater the diversity and number of insects we are likely to have and the greater the number ecological services they will provide.
More Information:
Further information and guidance on protected species and their management can be found here: