N at Maximum Sustainable Yield (MSY) = K/2

UNIT 3: Population Ecology Schueller EAS 509 11: Population Ecology Applied to…

1. Harmed species Demographics and sources of mortality 2. Harvested species Maximum sustainable yield (MSY), Marine Protected Areas (MPA), “certified sustainable” 3. Recovering species Minimum Viable Populations (MVP); Effective Population Size; Population viability analysis (PVA) 4. Humans: Do we have a K? https://www.census.gov/popclock/

Write down time and numbers For more on Wildlife & Fisheries management, Applied Population Ecology, etc. Take EAS 517. Conservation Biology With Brad Cardinale Hunt et al. 2017. Quantifying the demographic cost of human-related mortality to a raptor population. • Demographic analysis: Estimated stage- and gender- specific survival & fecundity of golden eagles • λ (lambda) - like r? • Spatially explicit: impact of wind farm • Did they use mark-recapture? • Result: stable population; mortality offset by reproduction and immigration Loss, et al. 2015. Direct Mortality of Birds from Anthropogenic Causes. Annual Review of Ecology, Evolution, and Systematics

UNIT 3: Population Ecology Schueller EAS 509 11: Population Ecology Applied to…

Chilean Sea Bass (a.k.a. White Gold, Patagonian Toothfish, Dissostichus eleginoides) Lifespan 50 yrs, 200 lbs, Reproductive at 8 yrs

Chilean Sea Bass (a.k.a. White Gold, Patagonian Toothfish, Dissostichus eleginoides)

Example: a population of fish. When we first meet, their density (N) is around K

How could we harvest fish sustainably?

Sustainably: get a sustained (or constant) yield without causing the population to crash (go to zero) harvest rate < ______Sustained yield: harvest rate < population growth rate So for maximum sustained harvest, we would want the population to be at its maximum growth rate. Where on the logistic growth curve is the population growing the fastest?

e d c

a Another way to look at this

Draw the Population curve for Growth Rate logistic growth (dN/dt)

Population Size (N) K Another way to look at this

Population Growth Rate (dN/dt)

Population Size (N) K N at Maximum Sustainable Yield (MSY) = K/2

Population Growth Rate (dN/dt)

Population Size (N) K Population of 200 = can harvest most fish per year Convince yourself: Is 75 per year (b) a better yield than if you harvested 300 every 5 years? Number of fish

e 400 d c 300

200 b

100 a 50

1 2 3 4 5 6 7 8 9 years Population of 200 = can harvest most fish per year Convince yourself: Is 75 per year (b) a better yield than if you harvested 300 every 5 years? Number of fish

e 400 d c This means 300 managed populations 200 b are kept 100 well below a K! 50

1 2 3 4 5 6 7 8 9 years Remember: What else limits population growth? (INVERSE density-dependent) Below minimum for …

Protection in numbers

Assistance in numbers Find unrelated mate (avoid inbreeding depression) Harvest = Selection for which life history strategies? r-selected K-selected When reproduce early delayed

Number of times single repeated reproduce

Size of offspring small large

Number of many few offspring Care of offspring none lots

Lifespan short long

Environment temporary, Stable, predictable, unpredictable, limited resources burst of resources Who? ‘pioneers’, good competitors dispersers, ‘weeds’

Back to MSY

= Population of 200 = can harvest most fish per year

Number of fish

e 400 d c 300

200 b

100 a 50

1 2 3 4 5 6 7 8 9 years MSY also applies to tree harvest What do you think determines rotation time? How fast the tree grows

The price of the wood? Quiz:

N at MSY= K/2 = 200 Does this mean you can harvest 200 per year?

Number of fish

e 400 d c 300

200 b

100 a 50

1 2 3 4 5 6 7 8 9 years Causes of biodiversity loss: Over-exploitation

Why do you think over-exploitation is especially common in large organisms and aquatic organisms? Obstacles to sustainable fisheries Obstacles to sustainable fisheries

1. “Tragedy of the commons” (get the wealth before someone else does)

But see: The tragedy of the commons -- minus the tragedy: Moritz et al. 2018 Emergent sustainability in open property regimes Obstacles to sustainable fisheries

2. Lack of knowledge

Population Size (N) K

Trawling vs. plowing a farm field Obstacles to sustainable fisheries 2. Lack of knowledge Solution: Use of TEK

• What makes TEK especially useful for population management? Obstacles to sustainable fisheries 2. Lack of knowledge Solution: Use of TEK

• Pacific island nation of Kiribati • Fish = 80% of annual protein consumption • Successful fishery management plan based on generational knowledge of historically productive areas (vs. only few years of monitoring)

Drew 2005. Use of Traditional Ecological Knowledge in Marine Conservation Obstacles to sustainable fisheries

3. Not leaving enough un-fished

What happens to the shape of this age pyramid with intense fishing? “Twenty years ago, we were catching toothfish that were five feet long and weighed up to 200 pounds,” Clark says.

“Today, we are catching fish that are two feet long and weigh 20 pounds.

Decreasing size is a classic sign of fish in trouble.” http://www.greenworks.tv/radio/earthtones/seabass.htm

3. Not leaving enough un-fished: Solution: Quotas & Marine Protected Areas (MPAs) Obstacles to sustainable fisheries 4. Direct and indirect effects “Bypass, by-catch, or by-kill” Example: “rock shrimp amounted to only 10% of total catch weight. Iridescent swimming crab, dusky flounder, inshore lizardfish, spot, brown shrimp, longspine swimming crabs, and other bycatch made up the rest”

“Nets with a combination of a turtle excluder device and bycatch reduction device reduced the catches of turtles by 99%” (Brewer et al. 2006) 4. Direct and indirect effects Obstacles to sustainable anything?

• Tragedy of the commons

• Lack of knowledge

• Lack of leaving enough un-harvested

• Direct and Indirect effects http://www.seafoodwatch.org/seafood-recommendations/our-app UNIT 3: Population Ecology Schueller EAS 509 11: Population Ecology Applied to…

What’s a viable population? Minimum viable population (MVP)

“smallest isolated population having a 99 % chance of remaining extant for 1000 years despite the foreseeable effects of demographic and environmental stochasticity, and natural catastrophes.” - Schaffer (1981)

How do you determine the MVP or any probability of persistence? Population viability analysis (PVA)

Deterministic kernel ex. Logistic growth

Stochasticity Demographic (variation in r) & environmental

Catastrophes Large, infrequent mortalities

Run many simulations Common steps Common Probability of persistence

Sensitivity analyses Effect of parameter variation

Add management options ex. Immigrants from captive breeding Primack, Fig 12.6 Real world MVP: One of the first uses of PVA- Grizzly Bears in Yellowstone

- Schaffer 1981: MVP = 50-90

- Allendorf 1994 – added more realism: not all bears breed! - Effective population size (Ne) is 25% of actual, so 200 bears ~ 50 Real world MVP: Track real populations over time

N = starting population numbers Bighorn sheep introductions in SW desert (Berger 1980) • 50-year study of 120 populations of different sizes • If starting > 100 individuals, then population persisted • If <50, population crashed CASE: Santa Catalina Island fox (Urocyon littoralis catalinae) • 1999 Outbreak of canine distemper virus (CDV) – probably via an unvaccinated pet dog

• In 1 year: Fox population on East W End from 1,300 to 130 • West End population stayed at 75 E

Challenge: - How would you address the cause of the decline? - How would you recover population size? To what? …both for long-term viability! Problems with captive breeding programs? UNIT 3: Population Ecology Schueller EAS 509 11: Population Ecology Applied to…

Do humans have a K? Have we exceeded it?

Calculate dN/dt (in minutes) for US and world We have learned so much about the ecology of populations. Can we apply it to humans? Do humans have a K? Have we exceeded it?

1010

107

104 100,000 10,000 1,000 100 10 Years to present We have learned so much about the ecology of populations. Can we apply it to humans? Do humans have a K? Have we exceeded it?

1010

7 10 Hunter-gatherers

104 100,000 10,000 1,000 100 10 Years to present We have learned so much about the ecology of populations. Can we apply it to humans? Do humans have a K? Have we exceeded it?

10 10 agriculture

107

104 100,000 10,000 1,000 100 10 Years to present We have learned so much about the ecology of populations. Can we apply it to humans? Do humans have a K? Have we exceeded it?

10 10 agriculture

107

Industrial revolution 104 100,000 10,000 1,000 100 10 Years to present We have learned so much about the ecology of populations. Can we apply it to humans? Do humans have a K? Have we exceeded it? It’s complicated! N • Changing K 10 globally 10 agriculture

107 industrialized nations

Industrial revolution 104 100,000 10,000 1,000 100 10 Years to present With Industrialization:

Declining death rate: Food & Health

Declining birth rate:

Culture, education, economics

…and EDCs?

See also Stiling Fig. 10.18 Skakkebaek, et al. 2015. Male Reproductive Disorders and Fertility Trends: Influences of Environment and Genetic Susceptibility. Physiological Reviews 96 (1): 55. Global trends? Already outdated predictions

Current = ? • The world's current human population of 7.6 billion is expected to double by 2200!

What is K? • Using the standard of living and resource consumption for the average U.S. citizen the earth has a K of 1 billion people!

Other estimates of earth's K: 7.5-12.8 billion On your own – watch: DON'T PANIC — Hans Rosling (statistician) on human population growth facts https://www.youtube.com/watch?v=FACK2knC08E Excellent discussion of consequences of cultural shift to smaller families worldwide – in terms of population growth curves and age pyramids – and of sustainable solutions to geographic distributions of larger populations Extra Optional Slides on Related Material Invasive Species Management – are they kept below K? Obstacles to sustainable …. 2. Lack of knowledge Solution: Use of TEK E.g. Grizzly bear demographic shifts • Found recent (30 year) change in resident population distribution • “two years of field work would have had limited meaning without the deeper time perspective provided by the Kitasoo/Xais’xais and the neighboring Heiltsuk First Nations.” • 10,000 years of place-based history + cutting edge genetic analyses https://www.raincoast.org/2014/07/grizzlies-islands/ Adding more realism to PVA and other population models • Spatially explicit (metapopulation dynamics)

• Age, size, or stage- structured (e.g. age-specific reproductive or survival rates) – Leslie Matrix model

• Include genetics! (Ne, …adaptive capacity) Michigan Wolves • 3 wolves in 1989, to over 600 wolves in 2013

• Jan 2012 removed from federal protection

• Dec 2012 – first open hunting season in MI

• 2014 back under federal protection (Endangered Species Act), upheld 2017 Winter break reading