Forest Gardens: evidence of increased biodiversity?

Thanks all for your wonderful contributions and offers of help. Do keep adding to this thread - the Environment Bill feels like a great opportunity for the communities we're hoping to support.

I'll let you know what the response from BANES is. I'll certainly be inviting the environment manager to our AGM!

that's fair enough - I wasn't intending to summarise the entire BUGs results as "trees are the answer", just that it's one element of the study that may be relevant to the OP

Many standard gardens have lower biodiversity because the owners
want it that way, and zap everything with nasty chemicals. It's much
harder to do that with trees, so this might be a reason for
encouraging more trees and shrubs in treeless gardens.

But 'trees are the answer' is probably an over-interpretation of the
BUGS results. On my reading of the published literature that came
out of BUGS the 'key to increasing biodiversity' was diversity of
habitat types. So yes, trees and shrubs would help a treeless
garden, but equally other habitats would help a fully-treed area. A
lawn and pond can be the equivalent of a clearing in a wood,
providing habitat variation and 'edge'. A bit of everything is best.

This is very exciting and makes me want to move to Bath!

So, the following is not directly related to Forest Gardens but may be useful....the BUGS study by Sheffield uni looked at biodiversity in urban gardens and found that presence of trees and shrubs is key to increasing biodoversity (ie compared to gardens that are solely lawns + herbaceous plantings.) Link including references to scientific papers below. Ken Thompson also published some of the findings as the book 'No Nettles Required'

http://www.bugs.group.shef.ac.uk/

Thanks for sharing, would love to know how your project progresses

At a tangent to your question, one of my on-hold projects is a community forest garden at Fairfield House, Bath. I was supposed to do an introduction to permaculture and forest gardening as fundraising event for Fairfield House the outcome of which was to engage the Rastafarian community to design and implement a forest garden. But it was booked exactly when covid kicked in, so was cancelled. Not sure when it is likely to happen now, but there is definite interest.

Hi Paul, I found this:

"Structurally complex habitats tend to contain more species and higher total abundances than simple habitats." (https://www.nature.com/articles/s41559-020-1281-8). The paper's example is coral reef, but I think this statement would equally apply to a structurally complex forest garden habitat.

Best wishes

Nigel

What a good conversation to have had and a great opportunity for BANEs. I’ll see what I can dig out and ask those taking part in my green space and healthcare course. One thing that strikes me, is that Forest Gardens are deliberately designed to encourage biodiversity to enable a complex natural eco-system to evolve over time. This is quite different from the principles that are used to design other types of community gardens. However, I guess that proving that FGs provide more biodiversity than a rewilding program for example is quite difficult. I’ll see what I can do to help.

Paul, Jake

Thank you, very kind.

I read it, comments attached.

Thanks. Its conclusion: there is a somewhat higher biodiversity in the Dartington forest garden than in Silverdale reclaimed woodlands (though statistically insignificant) … it should be researched more thoroughly to … promote Forest Gardens instead of both conventional forestry and agriculture … as a land restoration option as they have many outstanding traits.

Follow up could focus in on the striking increase in Hymenoptera (membrane winged insects including Bees and Wasps, Sawflies and Ants) - perhaps most important as they are perhaps the most beneficial insects for us. The soil creatures (Collembola/Springtails, Nematoda & Diplopoda) are also crucial for planetary health. These are what stand out in the chart in the jpg initially shared.

As promised by Jake, Mai got in touch. Here's her dissertation.

Thanks!

I had a reply from her, she's just checking it with the university—I gave her your contact details @Paul Pivcevic so she might get in touch direct 🙂

Thanks Jake. Unfortunately I was unable to get through or find the
reference. It would be useful.

You should be able to, this looks like Mai Vasudevan's LinkedIn profile https://www.linkedin.com/in/janani-quynh-mai-vasudevan-55422a94/. I've sent her a message 🙂

The attachment states that the differences were not statistically
significant, but the graphics suggest quite otherwise.

Is it possible to get a full copy of the report?

Could be posted on NFG site

'A comparative case study of biodiversity between forest gardens and reclaimed woodlands', dissertation by Mai Vasudevan of Keele University, featured in Agroforestry News Vol 27 No 4.

This might help https://www.heritagefund.org.uk/sites/default/files/media/attachments/Space%20to%20thrive_2019-A%20rapid%20evidence%20review%2014102019-accessible.pdf

Space to Thrive. A rapid evidence review of 395 papers on parks and green spaces for people and communities published last year.

One of their outcomes:

'The quality of green space has a stronger bearing on health outcomes than quantity'

The third of 3 recommendations:

'Parks and green spaces should be managed to encourage connections with nature. A wide range of habitats should be provided to give visitors the opportunity to engage with and better understand the natural world. This in turn will maximise the wellbeing benefits
associated with nature connectedness'

Best Wishes

Nickie

Space to thrive - National Lottery
Heritage Fund ( https://www.heritagefund.org.uk/sites/default/files/media/attachments/Space%20to%20thrive_2019-A%20rapid%20evidence%20review%2014102019-accessible.pdf )

Space to thrive – A rapid evidence review 1 Contents Executive Summary 2 Foreword 6 A note on definitions 8 Policy Context 11 Rapid evidence review methodology 14 Rapid evidence review findings 16 Health and wellbeing benefits of parks and green spaces

www.heritagefund.org.uk

Will do. Fantastic thread by the way, really encouraging. I've been looking at using native wildflowers for ornamental aspects of a forest garden for a client, increasing micro-habitats & food source. Exciting stuff 🙂

Yes please Jake!

Can folk please help with any further research demonstrating the value of forest gardening in respect of biodiversity, as compared with allotments or more conventional community gardens?

There is some research by a ecologist at Martin Crawford's site, it's in an Agroforestry News. I can dig it out for you if you like?

Nigel

My impression is that it's not the one extra species, but that
humans constantly interfere, creating rather dynamic systems and
'edges' or interfaces where diversity is especially great, perhaps
due to the ability to combine resources from multiple sources.
Digging and tilling for example constantly reset the ecological
clock and prevents it proceeding to climax, which is stable but has
relatively low biodiversity.

Jenny Owen thought it was to do with the huge number of habitat
types in a typical garden or perhaps allotment, tilled ground,
shrubs, rubble, compost, ponds, lawn, trees, dry bits, wet bits,
fertile bits, infertile bits, acid bits, alkaline bits, thousands of
micro-habitats.

Myself, I dunno!

Hi Peter,

Re. "Prof. Jane Memmot at Bristol found greater insect biodiversity on allotments than in nature reserves." Could that be because the allotment ecosystem's complexity includes humans in addition to other species? 🤔

Best wishes

Nigel

Dear Paul

You might find it difficult to get numbers because on the whole
people don't measure these things.

There are a few surprises in the literature. For example Prof. Jane
Memmot at Bristol found greater insect biodiversity on allotments
than in nature reserves. Jennifer Owen in her thirty-year study of a
garden in Leicestershire found over 2000 species of insects
including six 'new' ones.

It seems to come down to habitat diversity and this is probably
created inadvertently through dozens of small tweaks and
interventions, as well as nutrient inputs from compost etc. The
existence of trees creating a 'third dimension' both above and below
ground might well increase the tally, but equally it might not. Well
worth exploring, so I shall watch this project with interest.

Best wishes

Peter Harper