habitat mangement for native pollinators
TRANSCRIPT
Habitat Management for Native Pollinators
(and Natural Enemies)
Robyn McCallum, Nancy McLean and Chris Cutler November 2015
ACORN
How can we enhance agroecosystems?
Outline• What is habitat management? • How does it work? • What are some benefits of habitat management?
• Native pollinators in Atlantic Canada • Natural enemies • Biology • Their needs • How do we start thinking like them?
What are Native Pollinators?
Wild Bees• ~ 200 different bees in NS • ~ 900 different bees in Canada • ~ 20,000 worldwide
Bumble bees (Bombus)
Halictids
Image from entnemdept.ufl.edu
Image from discoverlife.org
Andrenids
Image from naturespot.org.uk
Image form bee-busy.com
Megachilids
Images from bugguide.net
Apidae
Image from beneficialbugs.org
Managed Pollinators
• Honey Bees • Alfalfa Leafcutter Bees • Bumble bees
Why are native pollinators important?
• conservation
• ‘insurance policy’
• free services- food and plant biodiversity
• challenges facing managed bees
• efficient & effective
• buzz pollination
VS
What are natural enemies?
• beneficial insects, parasitoids, predators
• Involved in pest control • E.g. beetles, wasps • Similar needs as pollinators
Why are natural enemies important?
• Biological control • Dual purpose- pollination • Nature takes care of itself
Image from atlanticpestsolutions.net
Image from ipm.iastate.edu
Native Bee Biology
Solitary vs Social Bees• Most bees are solitary • Cavity nesting, ground nesting
• Some are social - Honey bees ! hives - Bumble bees ! rodent holes
Nesting• Trees, stems, reeds,
under rocks, in old cars, in roof eaves, milk cartons
• Proximity of water
• Parasites- nesting aggregation
• Soil tillage
Food• Typically pollen & nectar from flowers, but also oils
• Specialists vs generalists
How can we manage nesting?
• Tubes for cavity-nesters
• Soil conditions for ground-nesters
How can we manage food?
• Floral plantings along field edge
• Marginal land, ditches, etc have also been used
• Provides habitat in addition to food at valuable times
• Annual and perennial wildflowers • Growing interest in “native flowers” • Important to have diversity of flowers- tongue
length, nectar rewards
• Important to note that bees and other pollinators need food throughout the season- before and after crop bloom
Nutrition
Foraging Range• Depends on body size,
species
• Affects foraging & access to flowers
• Ranges from ~100 m to 5 km
Emergence, Phenology
• Spring vs later in the season
• Varying adult life spans- weeks to months to years
• What happens if required flowers aren’t blooming at the right time? Climate change? Evolution? Tongue length example
Development• Bumble bees vs solitary bees
How do we think like bees?
• What are basic needs? Food, water,
habitat
Habitat Management
• Conservation biology ! improve availability of resources (Landis et al. 2000)
• Connecting habitat mgmt with pollinator abundance and crop yield ?
• Apple & highbush blueberry studies
Habitat ManagementPotential benefits include:
Alternative or complement to managed bees
Increased biodiversity
Increased biological
control
What Drives Conservation Biology?
Economic Factors
Conservation Concerns
What do I plant?
• Annuals & Perennials • Different bloom times • Different flower structures
• Red clover, alfalfa, sweet clover, buckwheat, black eyed susan, vetch, sunflowers
• Wild roses, goldenrod, St. John’s Wort • Phacelia? Wild bergamot? • Spring-flowering trees (willow, etc.)
• Takes time- both plant and bee establishment
Soil Prep• pH ** • Tillage • Habitat disturbance risks- mitigate with perennials
On-Farm Techniques
• Weeds for food- balancing act • Woodpiles for habitat • Setting aside poor land for flowers • Pollinator gardens
Public Concern for Native Pollinators
• Population decline? • Pesticides? • Pathogen spillover from managed hives (or vice
versa??) • Lack of habitat ** • Lack of food (flowers) **
Enhancing Native Pollinators and Natural Enemies in Wild
Blueberry Agroecosystems
• Many crops require pollinators for fruit set • Pollinator services from managed bees = high input
costs • Native pollinators are efficient, effective and already
present (Javorek et al. 2002)
Background
• Native pollinators provide important ‘free’ services
• Populations could be increased to become more economically important
Lowbush Blueberry
• Requires cross pollination • Pollination services can be #1 cost (honey bees, other
managed bees) • Unique cropping system (crop vs sprout) • Opportunity to enhance agroecosystem for pollinators
• Techniques to boost native pollinators & natural enemies
• Focused on habitat and food
Objectives
Habitat
Trap nests Clay lids
Food
Buckwheat Operation Pollinator
Buckwheat
• Can we plant buckwheat around the field to provide food after blueberry bloom?
Buckwheat
• Annual • Can tolerate low pH • Tolerates poor soil fertility • Improves soil structure • Doesn’t spread • Attractive to bees • Long blooming period • Used for honey bees
Buckwheat
Data Collection
Buckwheat results so far
Challenges• Producer inputs !tillage, seed, management (no spray), need to plant each year, perhaps 2x per season
• Drought • Deer
• Economic benefits? • Conservation benefits?
Habitat
Trap nests Clay lids
Food
Buckwheat Operation Pollinator
Operation Pollinator
• Mixture of annuals and perennials • Can we measure nectar content? • What is persistence like, weed invasion, etc?
Habitat
Trap nests Clay lids
Food
Buckwheat Operation Pollinator
• Trap nests for Osmia species (Hymenoptera: Megachilidae)
• Cavity-nesting bee, readily accepts artificial nests
• Known to be good pollinators
Habitat Management for Mason Bees
• Solitary
• 8-9 species involved in blueberry (Stubbs et al. 1997)
• Queen lays eggs on pollen provision, larva ! pupa ! emerges the next year (Torchio 1989; Bosch et al. 2001)
• Linear sequence of ‘cells’
Osmia Biology
• Adult life span! 3- 5 weeks • Can fly @ low temps and emerge early in season • Need mud to ‘cap’ their nests, so water source important
Osmia Biology
www.bugguide.net
• What species are involved? • Does nesting uptake differ from crop field
to sprout field? • When does nesting occur? • Are nests parasitized?
Questions
• 80 trap nests in 4 fields (64 wooden, 16 milk cartons)
• Placed 10 m apart along field edge and facing the sun, supported on stakes
• Set out 22 April in crop fields in northeastern Nova Scotia
Materials & Methods- 2014
Wooden Trap Nests
• Examined different hole diameters, rain cover, burning
• Tubes were 10 cm deep
• 12 tubes/ 2L carton • Tubes = 15 cm long • Varying diameters (7 and 9 mm) • Tubes from rolled white paper + newspaper and placed
through high-density polystyrene foam; spray foam insulation to support tubes (Sheffield et al. 2007)
• Cartons painted white
Milk Cartons
Results 2014Nesting Success
%
Succ
ess
0
18
35
53
70
Nest Typemilk carton wooden
• n =
n = 14
• Focused on milk cartons only • Compared crop and sprout
Materials & Methods- 2015
• Modified design • 16 tubes instead of 12 • All the same diameter (7 mm) • Added plastic straws
Milk Cartons- 2015
• 26/32 milk cartons had capped nests (81%) • 4 milk cartons were removed due to bear
damage
Results & Discussion- 2015
Question: Crop vs Sprout
• No significant difference
• Trade offs for nearby crop/sprout rotations (bees & pests)
Question: Timing
Phenology of Osmia Nesting in 2015
Tota
l # C
appe
d N
ests
0
35
70
105
140
Date12-Jun 26-Jun 1-Jul 10-Jul 17-Jul 22-Jul 31-Jul
• Blueberry Bloom
Question: Timing• Capped nests appeared
after blueberry bloom had finished
• Not all tubes were capped at the ends
• Queens likely nested in more than one tube
• TBD, as well as species of Osmia
Question: Parasitism
• Why are milk cartons attractive? -Longer tubes -Smell? -Pink Styrofoam? White carton?
• Landscape factors- water sources, previous populations, food throughout season
Discussion 2015
Implications for Industry & Science
• Better understanding of Osmia nesting biology & involvement in wild blueberry
• Nests could be moved to crop fields requiring pollinators
• Practical, inexpensive technique
Implications for Industry & Science
• More efficient pollination
• Biodiversity conservation
• Alternative & complement to managed bees
Diversity of pollinators demands a diversity of habitat management techniques
Global Importance• $ for farmers in Europe who implement
bee-friendly practices • Marketing strategy for US farms “bee
friendly farms” • “bee friendly” product labeling
Community Engagement
• Fact sheets for blueberry production • OP seed mix fact sheet • 4H pollinator project development • Grower field days • Industry meetings • Schools • Garden Clubs
Agvocate Challenge• We need more positive ag stories! • First blossom, bees, tractors, people • Use opportunity to share
Resources
• Lawrence Packer Lab, York University
• Sheila Colla- online resources • Nova Scotia Dept of Ag handout
re: bees • Discover Life • Bug Guide
AcknowledgementsCommittee Members
Dr. Paul Hoekstra, Syngenta Blueberry Producers of NS for Field Sites
Snake Patrol
