The Science behind increasing the biodiversity in our gardens and public spaces
The European Green belt - 12,500 km from Finland to Greece connecting the Baltic to the Adriatic sea
From Sussex Wildlife Trust booklet Maps from the State of Mendip AONB 2009-2014
Red - NATIONAL NATURE RESERVE Green - SSSI AND SPECIAL AREA OF CONSERVATION Brown - SSSI From the State of Mendip AONB Potential corridor areas
Parks Churchyards Community gardens
Schools 87% UK households have a garden
Estimate that in England area of gardens = 4 ½ x size National Nature reserves Private gardens Biodiversity in gardens In the 30 year study of her suburban Leicester garden, Jennifer Owen recorded :
• 436 sp. plants • 364 sp. butterflies and moths • 251 sp. beetles • 59 sp. bees • 94 sp. hoverflies • 80 sp. spider
• A total of 2,204 species in 34 groups Complexity of garden food webs
In a classic study at Imperial College , Broom (Cytisus scoparius) was found to support – 19 herbivores (3 Lepidoptera, 4 Diptera, 7 Coleoptera and 5 Hemiptera), 60 predators (insects, spiders, mites, harvestmen, birds) 66 parasitoids (mostly wasps, but a few flies).
In all, 370 trophic links were uncovered. UK Biodiversity Action Plan Priority Species found in gardens Common name Scientific name Birds Spotted flycatcher Muscicapa striata House sparrow Passer domesticus Tree sparrow (dunnock) Passer montanus Hedge sparrow (hedge accentor) Prunella modularis Bullfinch Pyrrhula pyrrhula Common starling Sturnus vulgaris Song thrush Turdus philomelos
Reptiles and amphibians Slow-worm Anguis fragilis Common toad Bufo bufo Grass snake Natrix natrix Great crested newt Triturus cristatus Common lizard Zootoca vivipara
Mammals Hedgehog Erinaceus europaeus Soprano pipistrelle bat Pipistrellus pygmaeus Brown long-eared bat Plecotus auritus
Biodiversity in terms of habitats
Ponds Shrubland Woodlands Meadows Wetlands
Within each of these habitats
Native/non-native Plant species Flower type
Plant height Flowering period The complete lifecycle
Winter Spring A few weeks in summer A resident bird’s year
Winter food Winter roost
Plenty of insects/insect caterpillars for young Nesting habitat Trees Key tree species for the Mendips
Small-leaved lime
Whitebeam Star ranking of trees in different categories
Tree species Wood decay Foliage inverts Biomass Blossom Fruits & inverts foliage inverts & nectar seeds
Native oaks 5 5 5 1 5
Hawthorn 3 4 3 5 4
Birches 4 5 4 1 4
Apple 3 4 3 4 4
Willows 3 5 3 5 1
Scots pine 4 4 4 1 4
Beech 5 3 1 1 5
Cherries 1 3 2 4 5
Sycamore 3 2 5 4 1
Could be as many as 80 species of moth whose larvae feed on Silver birch
Vapourer Buff tip
Pale tussock Purple thorn Shrubs
Native Blackthorn
Brown hairstreak Thecla betulae Alder buckthorn
Brimstone Gonepteryx rhamni Non-native Shrubs for birds Which berries are favourites ?
Blackbird -- hawthorn, rosehip, sloes Song thrush – yew, sloes, elder Mistle thrush – sloes, holly Redwing – hawthorn ( sloes too big)
Ivy is an important source of berries in late winter
Ivy flowers also important late food source
Shrubs as cover
Leaf litter and vegetation under shrubs important for invertebrates and detrivores Shrubs for roosting
Quote from the BTO
‘Gardens support a large number of roosting birds during winter. It is possible that these roosting opportunities are vital in helping some individuals to survive cold winter nights’ Shrub ground layer
Leaf litter food web Linear shrubs - hedges Hedges – vital corridors Hedges vital for bats Hedges
Many bird species will benefit
Feeding in the hedges and hedge trees Hedges for nesting birds Hedgehogs
Estimates are that the population has decreased by 25% in the last 10years
A census recorded approx. 30 million in the 1950’s, then only 1.5 million in 1995
Possible reasons for the decline
Loss of hedgerows Pesticides Smaller and tidier gardens Fences Isolation of populations Roads
Which plants to grow? RHS Plants for Bugs project For four years, the RHS staff and volunteers have tended and studied 36 plots, each of 3m x3m. Twelve are planted with native plants, 12 with 'near natives' and 12 with non-natives
Different methods used to collect the invertebrates RHS Bulletin 2 Aug 2017 - Gardens as habitats for plant-dwelling invertebrates
The best strategy for gardeners wanting to support plant-dwelling invertebrates in gardens is to plant a predominance of plants native to the UK.
Planting schemes based on near native plants may support only marginally fewer invertebrates than UK native schemes. Approximately 10% fewer
Planting schemes based on exotic plants will still support a good number of invertebrates, albeit around 20% fewer than UK natives
Regardless of plant origin, the more densely a planting scheme is planted or allowed to grow, the more invertebrates of all kinds (herbivores, predators, detritivores and omnivores) it will support. Which plant species to grow?
Study by Rollings and Goulson in 2019
4800 honey bees, 3400 bumblebees, 702 solitary bees, 624 hoverflies
Top of the list - Calamintha nepeta
Helenium autumnale Geranium rozanne
Marjoram Plants which had the greatest diversity of insects visiting Differing flower types is key Some important annuals Common bumblebees and their tongue length
Bombus hortorum – 12.00mm Bombus terrestris - 5.8kmm
Honey bee – 7mm B. pascuorum - 7.6mm B.pratorum – 6.4 mm How far do bumblebees travel for foraging?
Study by Goulson et all 2005
B.terrestris - 500 – 1,750m
B.lapidarius - 500 – 1,000m
B.pascuorum - 300 – 400 m
Carder bees generally known as ‘doorstep feeders’ < 500m Study done in Devon on pollen quality
Bumblebees need high quality pollen and this will drive their foraging activities
It was found that plants in the Pea family had pollen with the highest protein levels. Solitary bees There are about 240 species in UK
Mason bees Osmia sp. Leaf cutter bees Megachile sp. Wool Carder bee
One of the largest solitary bees which exclusively feeds from plants in the mint family and some from the pea family Hairy-footed flower bee Solitary bee nests
Sand bank built for solitary bees at RSPB Pagham harbour Hoverflies
Are approximately 260 species in UK
Adults feed on nectar and pollen but from generally flat-headed flowers
Larvae are specialist feeders – eg. rotting wood, fungi, bulbs, aphids There are likely to be as many as 30 - 40 species in a typical garden
The commonest species is likely to be - Episyrphus balteatus
Volucella zonaria
Eristalis intricarius Eristalis tenax - the drone fly Syrphini
Hoverflies in this group are migratory •1-4 billion have been recorded migrating in and out of southern UK •They are valuable pollinators
Episyrphus balteatus
Larvae of this large group are predators of aphids Scaeva pyrastri Eristalini
Larvae of this group are usually found in water or in manure/ sewage.
They feed on minute particles of organic matter.
Helophilus trivittatus
Myathropa florea Beetles are pollinators too! Diptera – also pollinators
Study by Bristol University of Diptera on 33 farms found non-hoverfly diptera were responsible for about 84% pollen carried. Butterflies Caterpillar food plants
Butterflies select the most diverse plant families, and just 4 families account for 60%.
•Grasses •Pea/bean family •Brassicas •Rosaceae Moths Decline of moth species due to a whole range of factors - . habitat loss . pesticide use . light pollution . climate change
Food for moth caterpillars
Native trees – eg. willow, birch, oak Shrubs – hawthorn, blackthorn, spindle, hazel, privet Fruit trees Roses, honeysuckle Native grasses Garden tiger
Nettles, docks
Elephant hawkmoth
Rosebay willowherb, Bedstraws Garden Ponds
There’s good news here, because about 16% of gardens contain ponds, so the total could add up to 3.5 million garden ponds, providing a total of about 350 hectares of pond habitat, which is a quarter the area of Lake Windemere. Importance of water Stone walls /piles Log piles Meadows Whole variety of different meadows Insects benefiting from a meadow area
Many of these species overwinter as eggs or pupae in the top of the soil or base of long grasses This has key implications for how we cut our grass! Birds benefiting from a meadow area
Creating linear ‘meadows’ Wildflowers on verges
To encourage a species-rich sward on verges a)Initially reduce cutting frequency to allow existing wildlflowers to establish. b) If necessary introduce some wildflower seed from local native species. Using cut hay from local meadows is ideal. Summary
•Create as many different habitats as possible to maximise biodiversity •Think about the whole life cycles of your garden residents/visitors • Work with, not against nature
We need to build resilient ecosystems and ones which are connected
“By managing their gardens for wildlife and beauty, gardeners provide an immense public benefit by enhancing the local environment, promoting sustainability, and A basic rule of Ecology - providing a major conservation resource for the benefit of everyone.” “ Everything is connected to everything else” Concept of Rewilding
This is taken further by the Professor of Ecology and Evolutionary Biology, Marc Bekoff who explains in his book ‘ Rewilding our hearts ’ that we need to become “reenchanted with nature, caring compassionately for all living creatures.”
“Rewilding is a mind-set. It reflects the desire to (re) connect intimately with all animals and landscapes in a way that dissolves borders.”