Measuring Productivity – Part I

Ecological Methodology LEC-11 Althoff

Population Biology 101

• Popn =

• For popn to _____: births+emigration > deaths + immigration

• ________________: adult population fails toreplace itself with self-sustaining individuals…

___________________…must be sustained by excess from other subpopulations

Key Definitions

• ______________ = number of offspring (young) produced during a reproductive cycle (season) by a population

• ______________ = number of young produced in a popn that reach sexual maturity

• ______________ = rate at which an individual produces offspring (young)

Key Definitions…BIRDS• ________________ = number of eggs that hatch per

nest (or group of nests). Not equivalent to nesting/ fledging success. -- egg per nest hatches or -- ____ of eggs hatching per nest

• __________ = young still in nest and/or unable to fly to leave natal site

• __________ = young left nest and/or natal site, able to fly

• _____________ > 1 nestling/hatchling fledges

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•

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•

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BIRDS

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• Key papers: Martin, T.E. and G.R. Geupel. 1993. Nest- monitoring plots: methods for locating nests and monitoring success. Journal of Field Ornithology 64(4):507-519. (on CLASSNOTES)

Winter, M., S.E. Hawks, J.A. Shaffer, and D.H. Johnson. 2003. Guidelines for finding nests of passerine birds in tallgrass prairie. Prairie Naturalist 35(3):197-211 (on CLASSNOTES)

BIRDS…nest searching & monitoring

• Key considerations:

T & E species

Human impact on searches & monitoring

Brood parasitism factor

Imperfect/uncertain nest/fledgling fate

BIRDS…nest searching & monitoring

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4

T & E Species 1

• Few left…. • Don’t want to

mark/band nestlings if can avoid it…but doesn’t help monitoring effort

• Always error to the side of caution…

• Examples: California condor ____________ Kirtland’s warbler

Human Impact on Nesting Success

2

• Nest often well camouflaged or cryptic… ___________

• ______________ to nest site “provides path” for ground predator (i.e., snakes, small mammals) or visual cues to aerial predators (i.e., crows) or retard growth of nestlings

Waterfowl nest predated before hatching

Brood parasitism3

• Affects determination of number of fledglings of host species ____ _____

• Could _____ “nest” success results….sometimes cowbirds mature/ fledge before host species young…or nest is abandoned prematurely

Brood parasitism …con’t3

• In some areas, for impacted host species, brood parasitism is ______...so probably not that big impact on estimation of productivity

• In some areas, for impacted host species, brood parasitism is ______...so significant impact on estimation of productivity

• Decision: is metric one uses…??? a) __________________________ (more helpful for determining recruitment) b) __________________________per unit

of area (cruder estimate of productivity)

Detailed Protocols….from nest initiation to fledgling

• Murphy, Robert K., Brian G. Root, Paul M. Mayer, J. Paul Goossen, and Karen A. Smith. 1999. A draft protocol for assessing piping plover reproductive success on Great Plains alkali lakes. Pages 90-107 in K.F. Higgins, M.R. Brashier, and C.D. Kruse (eds.), Proceedings, piping plovers and least terns of the Great Plains and nearby. South Dakota State University, Brookings.

Jamestown, ND: Northern Prairie Wildlife Research Center Online.http://www.npwrc.usgs.gov/resource/birds/pplover/index.htm(Version 08Oct99).

• Determine chronology of breeding season and monitor the stages. Requires detailed records including mapping

Note:1)Location of nests, no. eggs, etc.

2)No. of adults (1,2, or 3…i.e., breeding pairs

3)Behaviors (on nest?, courtship displays?, vocalizatons?)

Piping plover mapping

Piping Plover monitoring…con’t

• Start in early May• Visit individual alkaline lakes every

_____ days• Cannot “flag” nest….so use _____

(stone markers….10-30 ft/paces from nest location)

• Determine _____ of eggs, then…• Determine _____ of chicks (pre-

fledging), then…• Follow sites/lakes until all birds

“gone”…usually by early August

Te

rrito

ry

Est

ab

lishm

ent

Ne

st b

uild

ing

Egg laying4e, 4-5 d

Incubation25-27 d

Precoccial chicks 18-21 d

Fle

dg

e

MAY JUNE JULY AUG

Breeding ChronologyPiping Plover

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3

Piping Plover reporting…con’t

• Density of pairs (but “challenge” being a “shoreline” species)

• Clutch size (mean, median, mode)• Nest success - %• Egg /Hatching success - %• Chick survival post hatching - trend• Fledging success -%• Young produced per adult

< 1 chick fledged per adult

> 1 chick fledged per adult

steady or increasing

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Nest Survival/Success Analysis

• Most commonly used approach is the _________ METHOD (1961, 1975):

• Mayfield, H.F. 1961. Nesting success calculated from exposure. Wilson Bulletin 73:255-261.

• Mayfield, H.F. 1975. Suggestions for calculating nest success. Wilson Bulletin 87:456-466.

• Attempted to deal with “incomplete info” and provide guidelines (and consequences of those guidelines) for what to include in the analysis

Post-fledging Survival

• For most species, this is _____ most important piece of information to know

• For most species, this is _____ most difficult piece of information to obtain

a) challenge of tagging/marking individuals ___________________ them

b) challenge of __________ them examples:

piping plovers: “gone” in 18-21 d grasshopper sparrows: out of adult territory in 7-21 d

dabbling ducks: move from laketo lake in some regions

Proportional survival of _______________ (0-20 days) wood thrushes during years of low, moderate, and high rodent abundance southeastern New York. Schmidt, K.A., S.A. Rush, and R.S. Ostfeld. 2008. Wood thrush nest success and post-fledgling survival across a temporal pulse of small mammal abundance in an oak forest. Journal of Animal Ecology 77:830-837.

Interpret the wood thrush data

• What does the y-axis scale mean?

• What are the “vertical lines” extending from each “point” expressing?

• Why are all 3 “lines/trends” decreasing?

• Based on 18-20 d post-fledgling survival data, which, condition (high, moderate, or low) of small mammal abundance appears to negatively influence wood thrush survival the most?

Spot Mapping

• Requires ________ visits to a site/plot (usually 10 or more)

• Requires ability to detect species via _______ or _________ or both

• Aided by ability detect males vs. females (__________________________________)

• Aided by _________ (banded and/or radio-marked) of individuals

• Aided by knowing _____________________ associated with nest building, egg laying, incubating, feeding of young, alarm calls, etc.

Indirect Method – Reproductive Index

• ___________ Method: Vickery, P.D., Hunter, M.L. & Wells, J.V. 1992. Use of a new reproductive index to evaluate relationship between habitat quality and breeding success. Auk 109:697-705.

• Basic premise: _____________ reflect stage of breeding cycle and that for species with hard-to-find nest, this may be next best thing

• Specialized form of spot mapping• Used for grasshopper, savannah, and vesper

sparrows in Maine

Indirect Method “Scoring” System• Can score for entire breeding season or for individual

days• Rankings

0 = no territorial male present1 = territorial male present 4+ weeks2 = territorial male & female present 4+ weeks3 = pair found nest building, laying, incubating,

or giving distraction display4 = adults carrying food to presumed nestlings5 = evidence of fledgling success (1st brood)6 = evidence of fledgling success in either

brood, plus evidence of success in other7 = evidence of fledgling success in both broods

Indirect method

--basically spot

mapping

IndirectMethod

Evaluation of the Vickery Method

• Dickcissels -- too much brood parasitism in KSRivers, J.W., D.P.Althoff, P.S. Gipson, and J.S. Pontius. 2003.

Evaluation of a reproductive index to estimate dickcissel reproductive success. Journal of Wildlife Management 67:137-144.

• Grasshopper Sparrows & E. Meadowlarksshows promise for general trends in KS

Althoff, D.P., P.S. Gipson, J.S. Pontius, and R.D.Japuntich. 2009. Evaluation of a index to estimate grasshopper sparrow and eastern meadowlark reproductive success. Wildlife Biology in Practice 5(1):33-44.

Surveying -- Breeding Birds Only

• _______________ vs. _______________• May get __________…may get ________ to

breeding bird abundance• Greater the ____________ effort, more likely the

better estimates. Either more plots, more visits to plots/points…or both

• Has been used for some species to estimate _______________ produced

Standard Protocol

• ______________: 5-, 6-, or 10 minutes• “_______” conditions: Beaufort wind scale <3,

little to no wind• Typically start around sunrise to 10am, but some

evening survey for some species. Owls and other nocturnal species would be conducted at night

• Sometimes employee “______________” approach

Point count

example

Basic Utility of Data

• Monitor for many years…get __________• Compare productivity/breeding activity by

___________ and/or _____________ type• Compare productivity/breeding activity by

______________________.Ex. Burning patches every 1, 2, or 3 yearsEx. Removing mesopredators vs. control

• Measure ________________________ (natural or anthropogenic)