WFC 100 field methods midterm

monitoring

observing and describing patterns in abundance and distribution

answers quantitative questions: how many? where is a population or species? population trajectory? demography?

descriptive - what rather than why

particularly important for: exploited species to set sustainable harvest levels; threatened and endangered species at risk of decline

research

answering specific biological questions of hypotheses about the mechanisms and causes underlying an observed pattern

addresses mechanisms rather than outcomes alone

answers why and how questions

requires hypotheses and tests of those hypotheses

can be done through observation or experimentation

asks: why is species X here? why not Y? what allows so many individuals to be here? why not more or fewer? what drives behavior, density, or functional role of a species?

observation

no manipulation of animals or their environment

experiment

manipulating animal behavior, abundance, or environmental conditions

sample

a subset of an animal population

why sample?

determine species occurrence

determine population size/abundance

determine habitat use or requirements for a species

monitor changes in population size

monitor population dynamics

monitor effect of habitat change, management, or perturbation on pop size, behavior, species interactions

other specific research questions - what explains a biological/ecological phenomenon?

who to sample?

single population or demographic group within a population

single species

target groups (like vertebrates, birds, waterfowl, dabbling ducks)

all species in given area

what to measure when sampling?

abundance/density

habitat use and movement

demography (like birth, death, reproductive rates)

community metrics (like diversity, heterogeneity)

behavior

measuring abundance/density

presence/absence (occurence, distribution)

index of abundance (track/scat/calls; catch per unit effort)

relative abundance (proportion of sampled animals)

total counts (absolute count)

density (number per unit area)

measuring habitat use and movement

habitat use

habitat selection

home ranges and territories

migration routes, movement corridors

movement behavior

dispersal

dispersion (clumped, random, uniform)

measuring demography

reproduction and fitness (fecundity, young survival, age ratio)

survival (age-specific, seasonal, annual, perturbation)

immigration and emigration (natal, breeding, non-breeding)

measuring community metrics

species composition (relative abundance/proportion of each species)

diversity: richness - number of species; evenness - relative abundance; diversity index - index that combines richness and evenness

measuring behavior

foraging, feeding, hunting

mating

rearing young

movement and habitat use

social interactions

antipredator behavior

thermal management

communication

methods for estimation when sampling

index

direct count

mark-recapture

removal

transects

telemetry

drones and aerial imagery

passive observation (non-invasive)

ideally no direct contact with or influence on animals

passive monitoring using direct counts or indices (may count individuals, species, or behaviors)

can be less expensive and easier to implement

challenging for cryptic and rare species

passive observation examples

birds: binocular point counts

small mammals: track plates

large mammals: camera traps

fish: fisheries surveys

herps: coverboards

capture (invasive)

ideally no post-interaction differences

may include marking animals for future identification or deploying tracking device on animal

requires handling of animals

capture without marking more common for small, abundant species

capture with marking common for all wildlife (allows for repeated measure over time; could possibly affect animal health, fitness, or survival)

capture examples

birds and bats: mist nets

small mammals: Sherman traps, Tomahawk traps

large mammals: cages, culvert traps

fish: electro-fishing, long lines

herps: pitfall traps

marking examples

birds: leg bands

small and large mammals: ear tags

birds and mammals: tracking biologgers

fish, mammals, birds, herps: PIT tags

herps: visible implant elastomers

summary of research and monitoring

non-invasive (passive observation) and invasive (capture) techniques can be used in both monitoring and research

tools/approaches used vary by objective, questions, logistical captivity, funding availability, target group or species

essential before start of project to consider tools available and plan for safest and most appropriate methods

what are field notes?

biological notes recorded in (or near to) real time

generally without rigorous experimental or research structure

often qualitative and opportunistic

often include sketches, diagrams, etc.

purpose of field notes

capture and describe observations, phenomena and measurements that can't practically be recorded in a more structured framework

taking field notes

all field biologists take notes when they are in the field

details on species they are studying

surveys they are conducting

types of habitats and weather conditions

maps and spatial locations of their work

Elliot Coues

one of most important ornithologists of Nineteenth Century

offered advice in his Field Ornithology (1874) about writing down everything while it is fresh and writing it out in full

Joseph Grinnell (1877-1939)

coined the term niche

first director of UC Berkeley's Museum of Vertebrate Zoology

strong advocate for importance of detailed not-taking in natural history

resurvey projects have been done where Grinnell took notes previously

Grinnell Method

standard for field notes

4 components: field notebook, field journal, species accounts, catalog

field notebook

notes made in situ

often difficult to organize, scramble, edited, dirty, etc.

should still contain a complete record: sketches, maps, measurements

field journal

transcribed from field notebook

clean, organized, and faithful collection

can be digital, but hard copies should be kept

species account

detailed info and notes separated by species

ideal when you are learning new fauna

specific effort spent observing an individual or group

detailed description of appearances, habitat, behaviors, etc.

often repeated observation on an individual or group

catalog

tracks objects collected in field

often a separate book altogether

data include: unique item ID, date/location/method of collection, collector's name, description of object (may include measurements)

almost always digitized

why study birds?

visible/accesible

many niches

sensitive to environmental change

why census? - birds

basic inventory (species list)

trend analysis (changes in relative abundance)

monitor effect of some change or perturbation

specific research or monitoring questions

who to census? - birds

all species in a given area

target groups (like passerines, waterfowl, shorebirds, predators, pollinators)

single species

what to measure? - birds

presence/absence (distribution)

total abundance

relative abundance (number/unit effort)

density (number/unit area

spacing or habitat use

demography (reproduction/breeding, survival, morphology or subspecies)

common census methods

point counts

transects

area search

spot mapping

nest searches

mist nets and banding (with alternatives)

point counts - method

observer goes to fixed point

stays for fixed period of time

counts all birds seen or heard

record number, sex, distance

size of plot: fixed (50 or 100m), variable (observer estimates distance)

points counts - assumptions

all birds are detected

distance estimated correctly

each bird is independent

birds not counted >1x

observers have equal ability

observers do not influence birds

criteria to be counted are appropriate (flyovers?)

point counts - considerations

where to place stations?

how many stations?

how many visits to each?

how long to stay at each?

how large a plot?

differences in bird detectability

time of day, weather

point counts - value

simple, objective, repeatable, cheap

can use volunteers (training required)

can census large number of points quickly

can get +/-, relative abundance, density

transects - method

observer walks transects of fixed length

counts all birds seen or heard

records number, sex, distance, etc.

width of transect: fixed (50 or 100m), variable (observer estimates distance)

transects - assumptions

same as for point counts

observers keep constant pace in all areas

observer movements do not influence birds

transects - considerations

ease of walking (at constant pace)

problems of flushing (counting 2x)

estimating distance perpendicular to transect

transects - value

can cover more habitats along transect

can examine environmental gradients

flushing may be beneficial

can get +/-, relative abundance, density

area search - method

observer walks freely within a fixed area

counts all birds seen or heard in a fixed period

records number, sex, location

size of area: fixed (depends on study)

are search - considerations

ease of walking (at constant pace)

problems of flushing (counting 2x)

not strictly standardized

area searches - value

more like birders do

can track down and identify unknowns

benefits of both listening and flushing

spot mapping - method

observer marks territory locations of birds on a map

based on territorial behavior during breeding season

spot mapping - considerations

only used for territorial or sit-faithful species (breeding season)

very intensive observations; many visits

must be able to identify individuals

need good map of area

area surveyed is limited

spot mapping - value

provides very good data on density and space use

provides index of number of breeding birds

can do multiple species in an area

can find nests, secretive species

not useful for general surveys

nest search

search fixed plots intensively

look for nests (may be hard for some species)

provides index of productivity

may disturb nesting birds

roadside count

drive fixed road route

stop at fixed intervals

count all birds seen or heard for fixed time

can cover large areas, but only with roads

easy, simple, cheap

mist netting - method

series of fine nets

birds caught in net, removed, measured, and banded

mist netting and banding - value

provides large amounts of demographic data

age

proportion of young birds (age ratio)

body condition (fat, size, plumage wear)

breeding condition (molt, brood patch)

relative abundance (per unit effort)

survival (mark-recapture)

mist netting exposes birds to risk

ensure that your methods really require capture and handling

high logistical demands compared to observational methods

cardinal rules of mist-netting

never leave a net unattended (check every 15-30 min)

never mist net in rain or extreme temps

bird's safety comes 2nd after yours but above all else

don't go under net when birds are in net

clear net land of branches, vegetation

take off watches, rings, things that catch

alternative trapping techniques

corral trap

funnel trap

rocket net

bal-chatri traps (and similar)

noose mat

handling small birds

bander's grip (standard and safe)

photographer's grip (rare and risky)

band alternatives

neck collars

patagial tags

nasal saddles

capture and marking - considerations

injury and stress to bird (required training)

operation of nets (code of conduct)

standardized effort (do not sample known area)

location and number of traps

rain, wind, extreme temps

bird techniques summary

variety of techniques; depends on data need (+/-, density, productivity, survival)

counts (points counts, transects, area searches, road counts)

intensive mapping (spotmaps, nest search)

demographic studies (mist nets, banding, nest search)

ethics and laws for surveying small mammals

you are always responsible for the well-being of any animal you may capture

set and check traps, nets, etc. according to animal's schedule, not yours

always consider the least invasive methods possible

minimize impact on your study animals

if invasive methods are required, do the ends justify the means -> this may be subjective, be prepared to defend your case

ethics and laws requirements

state and possibly federal permits needed?

Institutional Animal Care and Use Committee (IACUC) approval needed?

if your actions have any potential to alter behavior of your study animal, you will probably need IACUC authorization

you will need a literature search: has this work been done before? are there alternative (less invasive) methods?

basic rules of field biology

never put yourself in danger - you can't rescue animals from traps if you break your leg

the animal always comes first (after you) - plan your meals and other events around needs of your study species

record data clearly, carefully, thoroughly - Grinnell Method remains popular because it works

methods for sampling mammals are segregated in 4 groups

1) small mammals (rodents, shrews/moles, smaller lagomorphs, small carnivores)

2) large mammals (ungulates, most carnivores, larger lagomorphs, etc.)

3) aerial mammals (mostly bats)

4) aquatic mammals (mostly whales, manatees, their allies)

study design

how should you allocate your sampling in the field?

random?

systematic?

stratified? -> stratified random (equal vs. proportional weighting?)

survey objectives

1) presence/absence only?

2) abundance? -> absolute numbers or relative abundance (relative to other species or to sampling effort)

3) density? -> numbers per unit area

additionally...

spatial or temporal comparisons at multiple levels

population structure/composition

community structure/composition

principal approaches

used for various groups, but mostly larger taxa

- observational, like line transects

- tracking

- photography

many types and approaches, focus today on trapping small mammals

- trapping

pitfall traps

particularly effective for shrews and other very small species that may not trip treadle on live trap

can be very effective

less selective

kill traps

usually for fossorial beasties

snap traps

usually for rats, mice, etc.

museum special snap trap made so skull remains intact when it snaps down behind the head

live traps

Sherman - folding or non-folding, aluminum or galvanized, solid sides or perforated, small to large

Tomahawk - mesh traps, single and double door traps

Havahart - used more by general population, not necessarily for research

trap placement

how should you arrange your traps in the field? -> transects? grids? webs?

equally important, how many traps should you use, and for how long should you sample? -> species/individual accumulation curves

accumulation curves

used to determine sampling effort

number of species documented as function of either number of animals captured or cumulative sampling effort

determine how many animals you need to sample or how long you need to sample before you have sampled a majority of the species

transect trapping

trap spacing may be fixed, semi-fixed, or variable

very useful for evaluating presence

particularly useful for learning where animals occur; the world is inherently heterogeneous

of value in obtaining relative abundances

if perpendicular distance over which animals are attracted to traps is known, density could be measured (but this is rarely the case)

useful for species strongly tied to runways (like voles) -> you aren't forced to place traps in poor locations

what to measure with transect trapping

presence/absence - yes (but documenting absence is always fraught with type 2 error or false negative)

abundance - yes (assumes all animals trappable)

relative abundance - yes (assumes equal trappability)

density - yes (if sampling area can be defined and determining area is often difficult)

what to measure with grid trapping

presence/absence - yes

abundance - yes (assumes all animals trappable)

relative abundance - yes (assumes equal trappability)

density - yes (but what is area covered?)

can use boundary strip or assessment line to determine area sampled

transect vs. grid?

compared in Montana, 2 forest types, 2 yrs

transects yielded more captures, more individuals, and more species than grids

differences between transects and grids tended to be greatest when small mammals numbers were lowest

transects appear to be more efficient than grids for small mammals, and provide better resolution of community structure for a given effort

web trapping

relax strong assumptions of closure in most models

relax need to know capture probabilities

however, ecological community has been slow to adopt webs

- novelty and underlying mathematics

- variable density of traps = variable impact of people walking (checking traps)

- webs likely best in open terrain (deserts, desert scrub) but less so in meadows, steppe, and other habitats with abundant ground-level vegetation

what to measure with web trapping

presence/absence - yes

abundance - yes (assumes all animals trappable)

relative abundance - yes (assumes equal trappability)

density - yes (area assessed as per point counts)

handling small mammals

scruffing

bird grip for larger species

removal methods

catch-per-unit-effort (CPUE) - essentially, linear regression of CPUE vs. total # removed

may be useful if associated with regular removal efforts associated with management

assumptions: closed population, equal detectability, all removals are known

CPUE estimates likely to be accurate and precise only if large proportion of population (>70-80%) is removed

capture-recapture/capture-mark-recapture methods

animals captured and marked in some manner (ear tags, toe clips, fur dyes or clips, ear tattoos, PIT tags, unique pelage patterns (spots, scars, etc.))

UV fluorescent marking

inject UV fluorescent tattoo ink subcutaneously into tail of small mammals species

cheap and ethical way of marking... although recommend long-term evaluations of mark retention and impact of tattoos (like visibility to predators)

estimating numbers with capture-recapture data

raw numbers - total number captured

- minor adjustment (minimum number known alive or MNKA) still does not account for differential probability of capture/observation)

estimators

- population closed (no gains, no losses) -> Lincoln-Peterson Index (2 samples), modified Schnabel Method (>2 samples)

- population open (may be gains and/or losses) -> Jolly-Seber, Cormack-Jolly-Seber

large mammal learning objectives

discover diversity of large mammals research methods available to wildlife biologists

discriminate between invasive and non-invasive capture techniques

determine appropriate methods for different species, environments, and scientific questions

large mammals means...

carnivores - canids (wolves, foxes), felids (cats), ursids (bears), mustelids (weasles), civets, etc.

ungulates - cervids (deer, caribou, moose), pigs, elephants, bovids (gazelles, antelopes, buffaloes, sheep), camelids, perissodactyla (horses, rhinos), etc.

not - primates, marine mammals (whales, porpoises, seals, sea lions)

invasive collection

requires animals capture to collect data

deploy biologgers to collect remote, continuous animal locations, temp sensors, body acceleration (energetics), individual survival estimates

collect samples like blood, whiskers, hair, scat, parasites

non-invasive collection

data can be collected without capturing animals

estimates of occupancy, population size

collect samples like hair, scat

capture methods: universal rules

get to animal quickly - animals can hurt themselves either through injury or stress; females with young may need to attend to young quickly

have safety plan - large mammals can be dangerous to work with and often live in remote, rugged areas; never engage in large mammal capture without a safety protocol

be familiar with species-species issues that may arise during capture to prevent animal injury or capture myopathy

be aware of surroundings; are there cliffs or water nearby? other animals that might attack individual you have captured once released or while in trap?

anesthesia

loss of consciousness and sensation, depresses nervous tissue centrally or locally

animal is unconscious

e.g. ketamine, telazol (tiletamine)

no reversals (antagonists)

sedation

pacifying, causes mild degree of depression to central nervous system

animal is not entirely unconscious

e.g. xylazine, medetomidine

reversals (antagonists) are available

combinations of anesthetic and sedative

e.g. telazol-xylazine, with yohimbine reversal

e.g. ketamine-medetomidine with atipamezole reversal

chemical immobilization key points

checking vital rates constantly is vital

rectal temp, heart rate, respiration rate

drug efficacy, safety, and dosage varies with species - essential to research which drug cocktail is most appropriate and safe for your study animal

leg-hold or foothold traps (capture)

often used for canids

try to spend as little time as possible setting trap, leave as little scent as possible, and disturb as little area as possible

tarp and gloves to reduce scent

brush and sticks funnel animal from single direction

pan used to save soil from hole

plastic bag keeps dirt from getting in release mechanism or spring

bait vs. lure

bait is for eating while lure is not for eating

lures can be from carnivore species itself (scat, urine, anal gland) or concentrated juices from potential prey carcasses

using carnivore scents rather than carcass scents can help reduce bycatch

snares (capture)

largely used for carnivores

types: foot snares and neck snares

can have fixed stop to allow smaller, non-target species to escape

place in precise location where animal is likely funneled through along movement route

important to check surrounding for animal safety

box traps (capture)

good for less savvy carnivores that don't mind walking into a trap (not wolves)

attach radio transmitter to door to allow for checking if trap is closed at distance

camouflaging depends on species... and researcher

culvert traps (capture)

largely used for bears

common for conflict mitigation and bear translocations

clover traps (capture)

specifically designed for deer

when researcher arrives at trap, either go in cage to tackle deer or collapse cage flat so soft net restrains deer

baited with alfalfa, grain, mistletoe, etc.

corral traps (capture)

for groups of animals or animals that cannot be restrained with other types of traps

good for wild boar