Todays activity day Google Hangout link
The first video conference will take place at 9.15 and the second at 2.30
A pond can host a huge variety of habitats for plants and animals depending on its size. There can be sloping beaches, muddy margins, shallow water with vegetation, overhanging trees and deeper open water. Some wildlife can only survive in ponds with specific conditions where as others are much more general.
In Alderney there a few larger ponds including Longis and Mannez pond but also many people have garden ponds. During March and April the WATCH group pond dip across 10 local ponds. Depending on the pond we can usually find masses of frogs and even Palmate newts. We found 91 Palmate newts in one pond last year. Damselfly larvae and dragonfly nymphs are a common find. These are great indicators of a ponds health.
It is very common to find vegetation in ponds and this
is usually hugely beneficial to the animals living there. However, there can be too much of a good thing and occasionally these plants grow out of control. This can occur naturally but more often than not it is caused by nutrient run off from agricultural land.
Mannez pond is suffering from an invasive plant species called Crassula helmsii or the New Zealand Pygmyweed. This is usually found at pond margins but it can take over entire ponds which is what is happening at Mannez. Crassula forms a mat over the pond blocking out sunlight and killing submerged plants. The dead matter from these plants lies on the bottom of the pond and is fed on by decomposers. Decomposers are great for cleaning up ponds but they use up a lot of oxygen. This all contributed to deoxygenation of the pond. This can be fatal for all animals that live there that need oxygen to survive.
This is one of our many projects this year and our reserves time are working very hard to come up with a solution to our problematic pond!!
- Have you ever been pond dipping? What did you find?
- Define deoxygenation. Why is this a bad thing?
- What species indicates a healthy pond?