If you have visited over the past couple of days you will have noticed some rather unusual and interesting kit arriving at the reserve. A huge floating digger has arrived with a very important job to do. Those of you that have been visiting us for some time might recognise this machine, as it was here back in 2005. So what is it here for?
Leighton Moss is in a valley bottom which means that we get water running into us from the valley sides. This water also brings sediment with it into the reserve. This sediment is very rich in nutrients and builds up in the bottom of the pools. As the layers build up there is less room for the water. The shallower water heats up on warmer days causing 'algal blooms' (algae is a sort of water weed, that in the right conditions grows very rapidly, covering an area, which is known as a 'bloom'). This blocks out light meaning the pools are no good for important aquatic plants to grow. Aquatic (water-loving) plants are a popular dish for ducks as well as being a vital food source and home for insects and fish, which in turn are important food for bitterns, herons, otters and more. When the sediment in the pools builds up, and algal blooms occur, this means that the aquatic plant, insect and fish populations decline and there is therefore less food available for other wildlife, which is obviously not good.
So what can we do about it? Well thanks to funding from Higher Level Stewardship (which comes from Natural England), we are able to bring in the very special machinery that you can see on the reserve at the moment. This large digger was originally developed in America for managing the vast swamp areas that they have. As you can see from the photo, it is no ordinary digger. If an normal digger were to try and drive into the pools, even with caterpillar tracks, it would sink if it hit a soft area. However, as the photo shows, this digger's caterpillar tracks have huge floatation devices, so if it hits a soft bit, it simply floats up and doesn't get stuck - genius! This machine is going to remove the sediment out of Public pool and then the back of Lower pool over the next couple of months. It will then be pumped out onto a farm on the edge of the reserve, where, because it is so rich in nutrients, it will act like garden compost once it is ploughed back in.
Check out those floats!
Last time the digger was here, in 2005, it was used to create new ditches to connect areas together. It also dredged the existing ditches, Lilian's pool and much of Grisedale pool. The effect of this work was almost instant. Prior to this work, otters had been absent from the site for 12 years, due to the lack of fish, but within a year of the work being carried out, they had returned to the site and have been here ever since. Now it is the turn of Public and Lower pools to get the same treatment, in order to make them an even more ideal home for the huge variety of wildlife that lives there.
Mud pumping on Lilian's pool in 2005
The work is going to take place during the week for the next couple of months. From previous experience, it causes minimal disturbance to the wildlife, which gets used to it very quickly. It will move the ducks and water birds from the pool that they are working on, but what is likely to happen is that the birds will move to Lower pool when the machines are on Public pool and vice versa. Last time the work was carried out, the workmen had great views of bitterns whilst they were working, so they seem unaffected by it going on.
We will of course keep you updated on here and in the visitor centre as to how the work is progressing. The hides will all be open as normal, so feel free to sit and watch this impressive and essential management work taking place to give nature a home.