Friends of mine who have ponds have the yearly struggle of trying to keep as many leaves out of the pond as possible, and then when enevitably some make it through any defeces they try to fish out the leaves from the pond without disturbing the wildlife.

I can understand in small ponds where the leaves can really fill it up that putting a net across the pond to stop the majority of the leaves would be a good idea, but if you have a wildlife pond then why remove the leaves when in nature ponds will naturally have a build up of leaves in them? Is their any real negative effect of having leaves?

I was discussing this with a friend today who makes sure every year that he has thinly spaced netting across the pond, which I think is a real eye sore!

The biggest detrimental effect of leaves in a pond is that the leaves decay and use the available oxygen. Leaves can also change the pH in a pond, making it considerably more acidic.

This may or may not affect wildlife ponds, but it certainly will kill fish in small ponds, unless aeration is being used.

Kingfisher

I agree with Kingfisher but I also think that because they are man made the ponds are not usually very large & are self contained with no water flow travelling through the pond ,so that the amount of leaves falling in can be disproportionate to the pond volume. A excessive build up of leaves will dacay on the bottom of the pond which then gives off toxic gases which replaces the oxygen. Once this cycle is allowed to carry on the pond will go stagnant & the water will then be smelly & lifeless.
Only netting it until the bulk of leaves have fallen & then skim off any escapees is a good idea.

That is true, nearly all natural ponds will have formed from a river or stream flowing into it which helps to reoxygenate the water and keeps the leaves from all decaying in one place. Thanks for both your answers! I was mainly talking about natural wildlife rather than fish ponds, where keeping leaves out is definitely needed.