"Oz" > wrote in message ...
> Jim Webster > writes
> >
> >"Buxqi" > wrote in message
> ...
> > >
> >> How is "marginal" land less valuable to wild species
> >> than is cultivable land?
> >
> >Well, which is more fertile on average?
> >>
> >
> >marginal land does tend to be marginal because of low fertility, and also
> >because it has been farmed less, as farming can increase the fertility over
> >time if you are doing it right

##
> Jim Webster wrote:
pearl wrote:
>>>>> ------- Land which is called 'marginal' is in reality essential to
>>>>> wildlife as natural habitat - it's some kind of natural ecosystem.
>>>>> Possibly including valuable human-edible and medicinal plants.---
>>>>
>>>> nonsense, you forget these landscapes were created by grazing, in
>>>> the UK water meadows, grazing marshes and the Lakeland fells and
>>>> uplands are all created by grazing animals
>>>
>>> What was there before?
>>
>> when?
##

IOW... this less fertile 'marginal' land has "always" been grazed.

And what's been said about such grazing and land degradation..?

Basically, jim, you're well and truly hoisted by your own petard.

> Its also worth remembering that, like humans, wildlife crops biomass.
> Fertile soils produce more biomass than infertile ones and thus ought to
> have more wildlife.
>
> Of course this isn't true where plants have gained the upper hand, pine
> forest for example, where biodiversity is low and non-plants relatively
> scarce compared to non-forest.

From Irish Forest Service Guidelines

'Forests are among the most diverse and complex ecosystems in
the world, providing a habitat for amultitude of flora and fauna.
Ireland's forests represent an important opportunity to conserve
and enhance biodiversity at both a local and national level.
...
The selection of tree species has a major influence on the habitat
value and biodiversity of a forest.

* Species diversity at the property, compartment and stand level
contributes to the habitat value and biodiversity of a forest.
Mixtures can include native and non-native broadleaves and
conifers, and must be silviculturally compatible. For example, the
light shade cast beneath a compatible mixture of broadleaves and
European larch encourages the development of native shrub and
ground layers.
* Favour broadleaf species as much as possible, where appropriate
to site conditions. In conifer forests, plant broadleaves in swathes
and not as single stems within the canopy. These swathes are
particularly valuable when positioned along the forest's external
and internal margins.
*Biodiversity also relates to the conservation and enhancement of
genetic biodiversity. Where possible, select native tree species
suited to the site and geographical location, ideally using local or
Irish provenances.
....'
https://www.agriculture.gov.ie/fores...odiversity.pdf