tree monkey

Yup and that's the problem, although most canal side locations are likely to be relatively species poor, not everywhere is, which is why I try to highlight the issue with the, urine is harmless comments. But often the reason the areas are rich in nettles and bramble is because the site is fertile, often from a excess of organic matter or some compound that acts as a fertiliser. Anyway I'm off for a bit

Yup, My point is valid though, fertilizers are wonderful in the right place, in the wrong place can have devastating impacts (seriously) and I get twitchy when I see it used as a casual justification for disposal of urine or any organic matter in fact, use it at home on your veggies where it will be really useful

The problem being the idea that fertiliser is good, it's common to see urine described as a fertiliser and most draw the conclusion that it is OK to dispose of it anywhere because "it's good for plants" The other issue here is how are you or anyone going to know which habitat the urine will not negatively effect. I am being slightly pedantic here because as I pointed out it's unlikely most canal side habitats are likely to be species rich but it's such a common misapprehension and can cause serious issues in the right (or wrong) place

Which was the point I made at the end of my post, what I was objecting to was the its a fertiliser so it must be good type comment, because they aren't universally good in fact they can harm habitats and lower species count, so your assertion that you found "The overwhelming consensus is that it does no harm and to the contrary, it supplies water and beneficial nutrients and is much 'appreciated' by most plants." Is a lack of understanding of how fertilizers effect habitats, like I say much canal side habitats are probably unlikely to be particularly rich but that's no excuse to claim it does not harm or is actually universally beneficial

Accepting that urine is beneficial as a fertiliser is fine, because it can be, drawing the conclusion that it is then OK to dispose of it in any random patch of ground is a misunderstanding of how fertiliser effects habitats. Over fertilisation can negatively effect species rich habitats, one of the ways of restablishing species rich hay meadows is regular removal of the hay and NO fertiliser, in fact in some cases they remove the rich top soil in an effort to lower the fertility The reality is most canal side habitats are fairly poor from a species point of view and it is unlikely to have much negative effect but the idea of it's a fertiliser so it must be OK to dump it is wrong