What is habitat recovery? How should we measure it?

What is habitat recovery? ��How should we measure it?

Professor Dawn R. BazelyBiology Department

A talk for the High Park Stewards group Sunday 24th January 2016, Toronto

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•  The Big Picture & its Consequences –  the Biodiversity Crisis

•  Responses – Habitat Restoration•  Our Carolinian Zone – Black Oak Savanna•  Can we restore lost & degraded habitat?•  A role for Citizen Science & gardeners

Most Canadians live within 100 km of the US border

Map – Gov’t of Canada

Southwestern Ontario:��the most densely settled part of Canada

•  Intense urban, industrial & agricultural land use

•  5-15% Natural Habitat cover

https://caroliniancanada.ca/

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The Biodiversity Crisis

•  “99% of all species that have existed are extinct and…

•  rates of extinction have varied enormously”•  “Are we currently in a period of mass

extinction?” •  Norman Myers (1976, Science v193:198)


•  Current extinction rates are estimated at 10-100 times greater than in the past

•  E.O. Wilson (right May 2015 at Harvard) called this the Biological Diversity Crisis (1985)


•  Causes of current mass extinction (Diamond 1989):•  1. Habitat destruction•  2. Habitat fragmentation•  3. Over-exploitation•  4. Introduced species•  5. Secondary effects or “chains of extinction”


•  Causes of current mass extinction (Diamond 1989):•  1. Habitat destruction•  2. Habitat fragmentation•  3. Over-exploitation•  4. Introduced species•  5. Secondary effects or “chains of extinction”


•  We can add to the list:•  Pollution (Lande 1999)•  Global climate change (Chapin et al. 2000)

•  All of these activities contribute to reduced species richness, genetic variation and the range of ecosystem types


•  We can add to the list:•  Pollution (Lande 1999)•  Global climate change (Chapin et al. 2000)

•  All of these activities contribute to reduced species richness, genetic variation and the range of ecosystem types

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•  The Big Picture & its Consequences – The Biodiversity Crisis

•  Responses – Restoration•  Our Carolinian Zone – Black Oak Savanna•  Can we restore lost & degraded habitat?•  A role for Citizen Science & gardeners

Responses – Restoration

•  Ecological Restoration – doing restoration•  Restoration Ecology – the study of it•  What should habitat managers aim for? •  How do we know if/when the goal was met?

If you buy a fixer-upper…

•  http://www.arcticcircle.ca/DehCho/Res/P6242126.jpg

Would you simply hand over 💰 to any contractor & not check up on them?

http://www.wwf.eu/media_centre/publications/living_planet_report/http://awsassets.wwf.ca/downloads/thenatureaudit_may2003.pdf

Responses – Restoration•  The Adaptive Management framework

(Hollings 1978) assumes:– Ecosystems, communities & populations are

dynamic & variable– Management action will be based on peer-

reviewed research– Sustainable management will involve trial and

error learning – Results will be tracked and benchmarked

The ecologist’s role in the ecological management model (yellow) (Figure by Norman Yan)

Report to Society

Gauge response of society

(Re)-assess societal goals

Are species or ecosystems

threatened or damaged? Identify

Stressor(s)

Model Stressor Action

Assess Possible Solutions

Apply Preferred Solution

Assess Effectiveness

Survey the condition of species & ecosystems

(re-) select bioindicators

Develop ecosystem

targets

Monitor the state of species

AssessmentPrevention/ Remediation

YesNo

Responses – Restoration

•  Adaptive Management is common sense:–  looks at the longer term –  highlights difficult trade-offs –  embraces alternatives–  explicitly acknowledges that there are ranges of

possible outcomes (Walters 1986)

–  Is the adaptive management approach usually successful? 😩 Sometimes…

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•  The Big Picture & its Consequences – The Biodiversity Crisis

•  Responses – Restoration•  Our Carolinian Zone – Black Oak Savanna•  Can we restore lost & degraded habitat?•  A role for Citizen Science – gardeners

Our Carolinian Zone

Our Carolinian plant communities

• Savannas - open forests, many prairie species

• Closed canopy forests

Backus Woods

Pinery Provincial Park

Our Carolinian Zone ��Black Oak & Red Cedar Savanna

• Open habitats with continuous ground cover & dominant tree species

• Fire-dependent • Many rare-in-Ontario

plant species• Habitat of the extirpated

Karner Blue butterfly, which feed on wild lupine (far right)

Our Carolinian Zone - Forests

• Diverse species composition • Delightful species such as

spicebush, tulip tree, and other more southern species

• Lots of interesting understorey herbs

Our Carolinian Zone – Ecosystem Pressures• Altered disturbance regimes:

– Too many people, too many deer, too little fire

• Changes in species:– Introduced species & both

indigenous & non-indigenous invasive species

Our Carolinian Zone habitats 1991-2005

•  Reduced cover of rare plant communities such as red cedar savanna & black oak savanna

•  Low forest & black oak savanna regeneration due to deer herbivory

•  Extirpation (local loss) of species•  Increased cover of non-

indigenous species

Our Carolinian Zone •  Management goals:1.  Restore appropriate

disturbance regimes – an ecosystem approach – Reduce deer densities– Reintroduce fire

2.  Reverse biodiversity losses – a plant community & species approach– Reintroduce native species– Remove non-indigenous species

Measuring Our Carolinian Zone Ecosystems

•  Individual species – numbers, size, where they are found

•  Plant community composition – how many species? cover?

•  Ecosystem metrics – light levels, soil moisture etc.

Our Carolinian Zone ��Non-native species in oak savannas

Pinery 4%

Rondeau 9%Pt. Pelée 11%

Our Carolinian Zone ��Point Pelée National Park

•  est. 1918 •  15 sq. km•  an agricultural and cottage

history•  37% of all plant spp. are

non-indigenous•  c. $250,000 on removing

non-native plants 1990-96

field

Oak savanna

Lessons learned… 13 years in the field

•  (1) “one size does not fit all” when it comes to assessing different management regimes

•  (2) “ a multi-scale approach is essential” – if you omit a scale, important habitat changes will likely be missed

•  (3) “change is slow” – some habitats may respond to management over decades, others more quickly

Method 1 - the deer exclosure 🐶

Rondeau vegetation plots:��- garlic mustard plots are orange ��- Bennett and Gardiner exclosures (1978) are red��- deer exclosures (1991&1994) are blue

Carolinian Zone Plots

Deer herbivory plots were integrated with new plots in the prescribed burn blocks to determine plant community response to prescribed burns.�� Black points are additional oak savanna plots (2000-2001)

Permanent plots in prescribed burn blocks – Pinery Provincial Park

•  In 2000 the circled areas were burned

•  Pinery has many burn blocks

•  We added dozens of plots to our existing (1994) deer exclosure plots

Carolinian Zone: Point Pelee National Park

Garlic mustard transects (15 transects)

Red cedar savanna plots (4 sites)

Oak savanna plots (10 transects)

Sometimes, you get lucky - there were also two “large” deer exclosures (40 x 60 m) in Rondeau (Gardiner & Bennett)

built in 1978

Method 2: the indicator species

Koh et al. 2010

Method 3: winter measurements

White-tailed deer Winter Browsing• Deer eat current annual growth or next year’s leaves of deciduous species

• Over time, high deer browsing, kills understorey shrubs

Rondeau deer exclosure built in 1978 seen in 1995

Out side, the canopy is more open and the native forest flowers are gone

Firanski & Bazely: The deer feedback

Method 4: air photos

• Effects of deer browsing can be seen from air

• Green patches = canopy gaps

• Measured in 1955 (right), 1972 and 1978

•  Carrie Firanski MSc thesis, YorkU

Forest gaps vs. deer numbers

The percentage of gaps (open forest area):1955 (24%) -1972 (26%)-1978 (30.5%) from air

photos

260

270

280

290

300

310

320

330

340

50 100 150 200 250 300 350 400deer number

gap

ha

y = .213x + 251.132, r2 = .998

gap ha

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Are Carolinian plant communities restored by deer management & burning?

•  2006 - Rick Hornsby at Rondeau –  Some non-native species declined, and Trillium returned but

a long-term lag effects of tree loss still, in 2009

Plant species richness in Pinery PP oak savanna with deer control & burning

Cecilia Tagliavia MSc. See also Etwell http://yorkspace.library.yorku.ca/xmlui/handle/10315/6353

0 10 20 30 40 50 60 70 80 900

10

20

30

40

50

60

70

80 additional BS & BWS

BWS

BS

PIN2000

PIN1999

PIN1994

Spec

ies

rich

ness

(# o

f spe

cies

)

Area (m2)

Spec

ies r

ichn

ess (

cum

ulat

ive

#)

Adaptive Management…

•  … common sense… •  … but difficult to implement…•  … because it emphasizes uncertainty, and

the need to constantly be learning about the way that a natural system behaves, and “tweaking” the management approaches used

Time frames...

•  Habitat recovery is often slow in forests…•  Rondeau PP: individual plant species

surviving in deer-grazed areas responded quite fast to repeated herd reductions from 1993 to early 2000s period (despite political pressure)

Restoration needs a multi-scale approach

•  But total plant community & ecosystem shifts towards more native species only happened by 2003-09 (nearly 10 year later)

•  we spent years figuring why plant community responses were slow…

•  … and did an unanticipated study of forest light levels…

If shade is increased will the missing species grow?

Ecosystem change is often slow

•  At Point Pelee NP, cottages were steadily removed from the park for restoration from the 1960s to the present time

•  We assessed cottage sites 1994-95 but didn’t see major species richness change until 2009–  (MacLachlan and Bazely 2001, 2003 Conservation Biology &

Biological Conservation)

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Negative Unexpected Restoration Results

•  As the Rondeau shrub understorey recovered from high deer numbers, cottage garden escapes like Japanese barberry spread widely

•  This wasn’t predicted in 1993...

Should eradication of non-natives be a restoration goal?•  NO – it’s rarely

achieved•  Reducing cover

should be a goal•  Over time, native

plants & their soil microbiomes can evolve to bite back & to compete with introduced species

http://yorkspace.library.yorku.ca/xmlui/handle/10315/18114

Positive Unexpected Restoration Results

•  Oak savanna species like Carex pensylvanica spread in the more open forest…

•  30% of Rondeau, previously closed-canopy forest is now managed as oak savanna with prescribed fire

Saewan Koh’s PhD thesis model

Evidence-based restoration:

•  Count things properly and analyze the data…we can all have quantitative data

•  Repeat measurements•  Be prepared to change & modify

management•  There will always be unexpected changes in

the plant community (Klotzli and Grootjans 2001)

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Citizen Science•  New technologies

allow citizens to play a role more easily than ever in Habitat Restoration & Species Recovery

•  They complement older techniques

Documenting Biodiversity��Ontario Bioblitz: Citizen Science •  https://twitter.com/OntarioBioblitz

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Habitat Restoration Gardening•  Gardeners can be educated by Citizen

Scientist neighbours to favour native black oak savanna species

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Habitat Restoration Gardening•  Gardeners can be educated by Citizen

Scientist neighbours to favour native black oak savanna species

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Habitat Restoration Gardening•  Ontario has many native plant gardening

resources–  https://twitter.com/OIPC1–  https://twitter.com/rbg_science–  https://twitter.com/tnanps✖%

✔%

Carolinian Canada ��Go Wild, Grow Wild – London ON 2016

•  https://caroliniancanada.ca/grow-wild/use-natural-gardening-techniques

Habitat Restoration Gardening

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Acknowledgements

•  This work was supported by many agencies: federal, provincial, municipal, and NGO, over the years.

•  York University supported many students.•  The ideas presented here were developed in

collaboration with many professors, conservation professionals and citizen scientists.