News Giant rat species discovered Great white shark in Massachusetts Xenoestrogens Frog calls Giant rat species discovered Great white shark in Massachusetts Xenoestrogens Frog calls

Population Ecology Population (N) Group of animals, identifiable by species, place, and time Defined wrt population biology Genetic definition would be more specific Individuals comprise a population Collective effects of individuals Natality, mortality, rate of increase Most management focused on populations, not necessarily individuals Population (N) Group of animals, identifiable by species, place, and time Defined wrt population biology Genetic definition would be more specific Individuals comprise a population Collective effects of individuals Natality, mortality, rate of increase Most management focused on populations, not necessarily individuals

Rates Natality Births (per something) Mortality Deaths (per something) Fecundity Number of eggs Female births/adult female Productivity Number of young produced Breeding system, sex and age ratios Recruitment (net growth = R) Natality Births (per something) Mortality Deaths (per something) Fecundity Number of eggs Female births/adult female Productivity Number of young produced Breeding system, sex and age ratios Recruitment (net growth = R)

Definitions Age structure Age pyramid Sex ratio Male:female Buck only deer hunting 1:10 QDM at Chesapeake Farms 1:1.5 Some dabbling ducks 10:1 Age structure Age pyramid Sex ratio Male:female Buck only deer hunting 1:10 QDM at Chesapeake Farms 1:1.5 Some dabbling ducks 10:1

Age Pyramids Long lived, slow turnover, low productivity, high juvenile survival Short lived, fast turnover, high productivity, low juvenile survival US population age pyramids

Sex Specific Age Pyramid males females Buck only hunting

Beavers

Population Growth Lambda Measure of population growth >1 population is growing <1 population is declining Important measure of pop status Lambda Measure of population growth >1 population is growing <1 population is declining Important measure of pop status

Exponential Growth Constant per capita rate of increase Constant percentage increase 10% per year Text “ever-increasing rate” per unit time Means number added per unit time is ever- increasing Population growth model Constant per capita rate of increase Constant percentage increase 10% per year Text “ever-increasing rate” per unit time Means number added per unit time is ever- increasing Population growth model

Exponential Growth George Reserve example GeorgeReserve Dr McCullough Estimated per capita growth rate for unencumbered growth (r m ) New species in optimal habitat Maximum per capita growth rate Unfortunately McCullough didn’t do it quite right. Why estimate it? George Reserve example GeorgeReserve Dr McCullough Estimated per capita growth rate for unencumbered growth (r m ) New species in optimal habitat Maximum per capita growth rate Unfortunately McCullough didn’t do it quite right. Why estimate it?

Logistic Growth Model Why worry about this? Fundamental conceptual relationship that underlies sustained yield harvesting NC deer population 1.1mm Harvest 265,000 Is that harvest a lot, a few? Will the population increase, decline, or what? Simple mathematical model Why worry about this? Fundamental conceptual relationship that underlies sustained yield harvesting NC deer population 1.1mm Harvest 265,000 Is that harvest a lot, a few? Will the population increase, decline, or what? Simple mathematical model

Logistic Growth Model Parameters have intuitive biological meaning K = carrying capacity N = population size r m = maximum per capita intrinsic growth rate (potential) Species and habitat specific r = realized (actual) per capita growth rate For exponential growth r = r m Only occurs for small populations for a short time McCullough should have estimated r m Parameters have intuitive biological meaning K = carrying capacity N = population size r m = maximum per capita intrinsic growth rate (potential) Species and habitat specific r = realized (actual) per capita growth rate For exponential growth r = r m Only occurs for small populations for a short time McCullough should have estimated r m

One specific form of sigmoid growth Growth model R = net growth = recruits K = carrying capacity r = realized growth rate One specific form of sigmoid growth Growth model R = net growth = recruits K = carrying capacity r = realized growth rate LogisticLogistic Growth Model LogisticLogistic Growth Model

As N approaches K, r = 0 When N small, then r = r m As N approaches K, r = 0 When N small, then r = r m

Logistic Growth Model Density-dependent growth

Density Dependent Growth Combined effects of natality and mortality Births decline as N increases Deaths increase as N increases Combined effects of natality and mortality Births decline as N increases Deaths increase as N increases

Density Dependent Growth Residual population (N) Population size which produces the recruits ( R) Pre-recruitment population Stock population Birth pulse population Births occur about the same time Deer in spring Residual population (N) Population size which produces the recruits ( R) Pre-recruitment population Stock population Birth pulse population Births occur about the same time Deer in spring

Sustained Yield See population growth model example Inflection point (I) Sigmoid curve slope changes from positive to negative Peak hump-shaped SY (or R) curve Maximum R per unit time Point of MSY See population growth model example Inflection point (I) Sigmoid curve slope changes from positive to negative Peak hump-shaped SY (or R) curve Maximum R per unit time Point of MSY

Sustained Yield Curves

Density Dependent Growth Fundamental relationship that underlies sigmoid growth. As N increases, per capita growth r decreases.

George Reserve Deer r per capita growth, h is per capita harvest rate Hump-shaped, not bell-shaped

George Reserve Deer MSY occurs at the inflection point I

George Reserve Deer Theoretically, sustainable harvests range from 0-90%; MSY about 50%

George Reserve Deer Harvest a number, say 30, then there is ambiguity. When a rate, h, then no ambiguity.

George Reserve Deer Right side of MSY (I) stable negative feedback between N and R

George Reserve Deer Left side of MSY (I) unstable Positive feedback between N and R

Logistic Growth Assumptions All individuals the same No time lags Obviously, overly simplistic Does provide conceptual bases for management. All individuals the same No time lags Obviously, overly simplistic Does provide conceptual bases for management.

Population Models Forces thinking Conceptual value Requires data What needs to be known? How are those data acquired? Predict future conditions Assess management alternatives Forces thinking Conceptual value Requires data What needs to be known? How are those data acquired? Predict future conditions Assess management alternatives

NC Deer NC deer population 1.1mm Harvest 265,000 Can this model suggest anything about the harvest level in NC?

NC Deer NC deer population 1.1mm Harvest 265,000

Density Dependent Factors Density dependent (proportional) Mortality Natality Density independent Asian openbill storks example Compensatory mortality and natality Density dependent (proportional) Mortality Natality Density independent Asian openbill storks example Compensatory mortality and natality

Isle Royale Lessens Wolves Moos e

Isle Royale Lessons Predator/prey dynamic balance? Populations fluctuate due to a myriad of factors Food, disease, weather, competition, genetics, random events, etc. Disequilibrium No such thing as the “balance of nature” Predator/prey dynamic balance? Populations fluctuate due to a myriad of factors Food, disease, weather, competition, genetics, random events, etc. Disequilibrium No such thing as the “balance of nature”

Demographic Rates Birth rate (b) Death rate (d) Emigration (e) Immigration (i) Realized population growth rate r Birth rate (b) Death rate (d) Emigration (e) Immigration (i) Realized population growth rate r

Definitions Sex ratios and mating systems Know them!!! Not going to repeat all of them here!!!! Sex ratios and mating systems Know them!!! Not going to repeat all of them here!!!!

Importance to Management Sex ratio and breeding systems Monogamous Balanced sex ratio Ducks -- sexually dimorphic Sexes w/ different susceptibility to predation, hunting Canada geese -- monomorphic Polygynous Manage for a preponderance of females Pheasants, turkeys -- dimorphic Ruffed grouse, quail -- monomorphic Promiscuous Deer To grow, unbalanced sex ratio QDM, balanced sex ratio Sex ratio and breeding systems Monogamous Balanced sex ratio Ducks -- sexually dimorphic Sexes w/ different susceptibility to predation, hunting Canada geese -- monomorphic Polygynous Manage for a preponderance of females Pheasants, turkeys -- dimorphic Ruffed grouse, quail -- monomorphic Promiscuous Deer To grow, unbalanced sex ratio QDM, balanced sex ratio

Age-Specific Birth Rates

Age-Specific Natality Deer reproduction Table 5-2 PA dense, IA sparse Fawns pregnant only in Iowa Fawns only breed when populations are low Corpora lutea per doe (ovulation sites) Less in PA (1.6) than in IA (2.23) Fetuses/pregnant doe Less in PA (1.4) than in IA (2.1) George Reserve r m = Deer reproduction Table 5-2 PA dense, IA sparse Fawns pregnant only in Iowa Fawns only breed when populations are low Corpora lutea per doe (ovulation sites) Less in PA (1.6) than in IA (2.23) Fetuses/pregnant doe Less in PA (1.4) than in IA (2.1) George Reserve r m = 0.956

Additive vs. Compensatory Harvest rate Survival rate Compensation Additive

Additive vs. Compensatory Additive mortality As more mortality factors are added, e.g. hunting, survival decreases Compensatory mortality As more mortality factors are added, survival remains the same (up to a point). Rationale to justify hunting Would have died anyway, why not by hunting? In terms of N remaining constant, could be compensation in natality, mortality, both Additive mortality As more mortality factors are added, e.g. hunting, survival decreases Compensatory mortality As more mortality factors are added, survival remains the same (up to a point). Rationale to justify hunting Would have died anyway, why not by hunting? In terms of N remaining constant, could be compensation in natality, mortality, both

Survivorship Curves BioEd Online

Survivorship Curves

Life Tables Actuarial tables

Life Tables xlxlx dxdx q x = d x /l x exex /1000= = /946=0.153 Table 5.4

Life Tables life tables.xls Methods to calculate life tables.xls Birth rates and death rates constant for appropriate time (life span) Age distribution (S x ) must be stable S x is the proportion of the number born that are alive at a given age f x /f 0 Mark individuals at birth and record age at death (l x ) Calculate number dying in a particular interval Know number alive at age x and x+1 (l x ) Know age distribution and rate of increase l x = product of S x and rate of increase, i.e., number born What to estimate? N might be enough Demographic rates more diagnostic life tables.xls Methods to calculate life tables.xls Birth rates and death rates constant for appropriate time (life span) Age distribution (S x ) must be stable S x is the proportion of the number born that are alive at a given age f x /f 0 Mark individuals at birth and record age at death (l x ) Calculate number dying in a particular interval Know number alive at age x and x+1 (l x ) Know age distribution and rate of increase l x = product of S x and rate of increase, i.e., number born What to estimate? N might be enough Demographic rates more diagnostic

Life Tables Take home message Need constant schedules of mortality and natality so the age distribution stabilizes Nearly impossible to meet these conditions for wild populations So, actually constructing a life table for a wild population is not likely to be possible BUT, life tables are of great conceptual value in modeling populations Take home message Need constant schedules of mortality and natality so the age distribution stabilizes Nearly impossible to meet these conditions for wild populations So, actually constructing a life table for a wild population is not likely to be possible BUT, life tables are of great conceptual value in modeling populations

Population Data Two problems in estimating N First observability Proportion of animals seen p is observability C = count Two problems in estimating N First observability Proportion of animals seen p is observability C = count

Estimating N Count 43 salamanders and you know you observe 10%, then

Population Data Two problems in estimating N Second sampling Too expensive in time and money to count everywhere all the time. Estimating populations and demographic rates is another course FW 453/553 Graduate course by Dr. Pollock Two problems in estimating N Second sampling Too expensive in time and money to count everywhere all the time. Estimating populations and demographic rates is another course FW 453/553 Graduate course by Dr. Pollock

Population Index Population Index = assume p is constant Used to make comparisons over time or space Unfortunately, probably rarely true.

HIP and Duck Stamps Migratory Bird Harvest Information System HIP certification on hunting license Used to sample hunters of doves, woodcock, and other webless migratory birds Duck Stamps All duck, geese, swan hunters purchase 1934 drawn by “Ding” Darling $600mm for refuges Used to sample hunters Migratory Bird Harvest Information System HIP certification on hunting license Used to sample hunters of doves, woodcock, and other webless migratory birds Duck Stamps All duck, geese, swan hunters purchase 1934 drawn by “Ding” Darling $600mm for refuges Used to sample hunters

BBS Breeding Bird Survey Volunteers About 4,000 routes in US and Canada 50 stops on roads at 1/2 mile intervals Record birds seen and heard w/i 1/4 mi Began 1966 Over 40 years of trend data BBS Breeding Bird Survey Volunteers About 4,000 routes in US and Canada 50 stops on roads at 1/2 mile intervals Record birds seen and heard w/i 1/4 mi Began 1966 Over 40 years of trend data BBS

Bird Banding Amateur and professionals Federal bird banding lab Early 1900’s # bands, color, petagial tags, collars, etc. Migration patterns, distributions, survival, behavior, philopatry Amateur and professionals Federal bird banding lab Early 1900’s # bands, color, petagial tags, collars, etc. Migration patterns, distributions, survival, behavior, philopatry

Patuxent Wildlife Res. Center 1936 USGS Patuxent BBL, BBS, zoo curators, scientists, toxicologists Whooping cranes Video Ultralight 1936 USGS Patuxent BBL, BBS, zoo curators, scientists, toxicologists Whooping cranes Video Ultralight

Metapopulations Subpopulations of varying sizes somewhat isolated from each other Genetic exchange within subpopulations > between them Subpopulations might wink in and out of existence Unoccupied patches still important Dispersal and recolonization are critically important Habitat fragmentation might exacerbate Model Subpopulations of varying sizes somewhat isolated from each other Genetic exchange within subpopulations > between them Subpopulations might wink in and out of existence Unoccupied patches still important Dispersal and recolonization are critically important Habitat fragmentation might exacerbate Model