Amphibian Exam Flashcards
1
Q
Why are herps grouped together?
A
○ Because they share characteristics:
§ Ectothermy
§ Body size and shape
§ Highly data deficient
§ Highly threatened
§ Highly awesome
2
Q
What does the latin word herpes mean?
A
a creeping thing
3
Q
Why groups amphibians and reptiles?
A
○ Early taxonomists lumped them since they were seen as “foul and loathsome” (from Linnaeus)
○ From the Latin word herpes - ‘a creeping thing’
§ Because they are both creepy?
§ Because they creep along the ground?
○ Because they share characteristics:
§ Ectothermy
§ Body size and shape
§ Highly data deficient
§ Highly threatened
§ Highly awesome
4
Q
What is an ectotherm’s way of business?
A
Ectotherms use an outside source of energy to raise their body temps
Being an ectotherm has implications for all aspects of an animal’s life
5
Q
What does ectothermy translate to?
A
lower energetic costs and food requirements for ectotherms
6
Q
What are the constraints of ectothermy?
A
their activity is more constricted
§ Daily
§ Seasonally
7
Q
How do endotherms use most of their energy and how are ectotherms more efficient?
A
○ Endotherms have to use ~99% of the energy they get from food to stay warm. Ectotherms get all of this from the environment (energy savings!)
8
Q
What is the relationship between biomass and amphibians?
A
they kick biomass?
9
Q
describe amphibian body shape and size
A
○ Small! (but not always)
§ More than half of herps weigh less than 10 grams
The smallest herps are 10X smaller than the smallest birds and mammals
10
Q
What threats are amphibians vulnerable to?
A
○ Invasive species
○ Climate change
○ Habitat loss/land use change
○ Disease
○ Pollution
○ Overexploitation
11
Q
What is a clade?
A
group of organisms believed to have evolved from a common ancestor
12
Q
What are the three orders that make up the class amphibia?
A
Gymnophiona
Caudata (Urodela also)
Anura
13
Q
What is taxonomy?
A
the science of classifying organisms
14
Q
What is a cladogram or phylogenetic tree?
A
a diagram used to represent a hypothesis about relationships between groups of organisms, often constructed using synapomorphies
15
Q
What are synapomorphies?
A
shared characteristics that are common between an ancestor and its descendants
16
Q
What are the parts of a phylogenetic tree?
A
○ A simple phylogenetic tree
○ Clade - common ancestor and all its descendants and taxa
○ Node - point at which common ancestor gives rise to 2 sister lineages or branches
○ Stem - region between two nodes
17
Q
Why are phylogenetic trees important?
A
○ Phylogenies tells us about the evolution of morphology, behavior, ecology, and tons of other things about organisms
○ Homologous evolution: organisms inherit similar physical features from a common ancestor
○ Convergent evolution: analogous structure are evolved independently due to similar environmental pressures
18
Q
What is a monophyly?
A
an ancestor and all their descendants
19
Q
What is a paraphyly?
A
an ancestor and some of their descendants
20
Q
What is a polyphyly?
A
descendants that do not share a common ancestor
21
Q
What kind of group are amphibians?
A
- Extant amphibians are a monophyly group
22
Q
What is the difference between urodela and caudata?
A
Urodela only include the extant species, and caudata includes all extant and fossil groups
23
Q
What species are in the gymnophiona order?
A
Caecilians
24
Q
What species are in the urodela order?
A
salamanders, includes newts
25
What species are in the Anura order?
frogs, includes toads
26
what does caecilian stand for?
blind ones
27
What does gymnophiona stand for?
naked snake
28
Describe what caecilians look like
○ Elongate, legless, burrowing
○ Small tail or no tail
○ No legs! Not even vestigial ones
○ Head w/ a scull and sometimes eyes and powerful jaws
○ Two rows of sharp teeth!
○ Paired tentacles between eyes and nostrils - "sixth sense"
○ A long body with a backbone and strong muscles
29
Where do caecilians live?
○ Much unknown about these species
○ Spend entire life underground or in water
30
Describe the amount of caecilians and where they are found
○ 9 families worldwide, 222 species total, only in the tropics, largest concentration of species in South America
31
How do caecilians reproduce?
In some species, embryos develop internally, and feed on lipid-rich substances they scrap from the walls of the oviduct with specialized "fetal teeth"
Others lay and guard egg
32
Describe the parental care in caecilians
The skin of some caecilian species is transformed in brooding females to provide a rich supply of nutrients for the developing offspring
Young animals are equipped with a specialized dentition, which they use to peel and eat the outer layer of their mother's modified skin
33
How many families are there in the order Urodela
10 families worldwide
34
How many species of urodela are there
816 species total
35
Where is the largest concentration of urodela?
largest concentration in Appalachian Mountains/SE USA
36
What percent of salamanders are amphibians in the world?
~10% of amphibians are salamanders
37
In North America, how many amphibians are salamanders?
~50% of amphibians are salamanders
38
How many amphibians are salamanders in Appalachia?
60-70% of amphibians are salamanders
39
Describe where the major salamander lineages are
North America harbors 9 of 10 major salamander lineages
SE U.S. harbors 7 of 10 major lineages
40
What is tail autonomy in urodelans?
Predator defense
Dominance displays with conspecifics or competitors
41
What is the caudata life history?
4 limbs with elongate trunks and tails
Many have aquatic eggs into aquatic larvae, but…
Have evolved a wide variety of modes: some entirely terrestrial, some entirely aquatic, some "biphasic"
42
How many anura species are there?
7,806 species
43
How many families are there in the order anura?
29 families and ~ 7800 species
44
Where is anura diversity the highest?
Diversity is highest in South America
45
What is a frog?
Unique among vertebrates
□ Short body
□ Mostly tail-less bodies as adults (Anuras translates to "lack of a tail")
□ Flat head, big mouth
□ Long, muscular hind limbs
46
What are some common characteristics of amphibians?
○ Three-chambered heart (2 atria, 1 ventricle)
○ Skin adaptions (today)
○ Importance of water/temp regulation
○ Complex life cycles
○ Ecologically important
○ Complex communication pathways
47
What roles does amphibian skin play a role in?
Respiration
Courtship
Defense
Crypsis
48
Describe respiration in amphibian skin
○ High vascularized skin maximizes the intake of O2 and excretion of CO2
○ Some species use skin and lungs, but some rely more heavily on one versus the other
○ Many unique morphological skin adaptations
§ Skin folds for increasing oxygen intake
§ Male incubate eggs and use skin to circulate water, bringing oxygen to the eggs
49
What is amphibian skin made of?
amphibians lack epidermal scales (like reptiles) but some do have keratin structure
50
What are some amphibian skin structures?
Some have tools for digging (e.g., "spades")
Seasonal nuptial pads associated with breeding (e.g., "claws")
Spines!
Nuptial pads (can be used to ID males of some species, depending on time of year)
51
What are the physical defenses of amphibian skin structures?
□ Bony protrusions from skull used to inject skin poisons
□ One gram of the toxic secretion from A. brumoi could kill more than 300,000 mice or approximately 80 humans, making it 25 times more potent than pit viper venom
52
What is a chemical defense of amphibian skin?
Poison [granular] glands
Parotid glands
53
What are the behavioral defenses of amphibian skin?
□ Gland secretions in conjunction with unkenreflex -- the ultimate defense
® A contortion to show hidden bright colors, while releasing poison from glands
® Serves as a warning to predators
54
What is crypsis?
camouflage/leaf mimicry
55
What are the pigment cells in amphibians?
chromatophores
- Melanophores - black, brown, or red
- Iridophores - reflect light
- Xanthophores - yellow, orange, or red
- Different combinations of the above are what produce different colors
56
What does monochromatic mean?
do not change over their life cycle
57
What does dichromatic mean?
do change color over their life cycle
58
What does dynamically dichromatic mean?
change color repeatedly over their lives, typically seasonally
59
What can amphibian skin do in regards to their surrounding?
rapid color changes based on surroundings
60
What are the three distinct stages of the typical life cycle?
Egg
Larval
Adult
61
What are some other life cycles of amphibians?
Direct development
Paedomorphism (keeps juvenile characteristics)
62
Describe the Eastern Newts life cycle
○ Nonreproductive terrestrial stage
§ Up to 14 years
○ Become fully aquatic adults and reproduce
63
What is the relationship between amphibians and water?
○ Water is a big deal to amphibians!
§ Amphibians are 75-85% water
○ How do they maintain their water balance?
§ Evolved traits -- morphology and physiology
§ Behavior -- decrease surface area
§ Habitat selection and timing -- cool and moist
□ Soil, water, rain, etc..
64
What does a seat patch/drink patch/ pelvic patch do?
○ Common in Bufonidae
○ Ventral pelvic patch that functions to absorb water from substrate
65
What do waxy tree frogs do to retain water
○ Are able to secrete a waxy substance and spread it across their body in order to lock in moisture on their bodies
66
How does posture help regulate water?
○ Maximize contact of ventral body surface with damp substrate
§ Minimizes surface area exposed
§ Reduces evaporative water loss through the skin
67
What do amphibians do in extreme cold?
§ Brumation (ectotherm hibernation)
§ Freeze tolerance
68
What do amphibians do in extreme heat?
Aestivation (prolonged torpor or dormancy of an animal during a hot or dry period)
69
What is cold tolerance and overwintering?
Move to microhabitats that don't freeze
□ Burrows below frost line
□ Other refugia
□ Flowing, well-oxygenated water
Freezing (freeze tolerance)
70
What is brumation?
○ Behavioral response in ectotherms to changing seasons and resource availability
§ The ectotherm version of hibernation
○ Removes the animal from environment that are likely to experience temperatures low enough to kill (below frost line)
71
What are the habitats of brumation?
○ May take place underground, under water, inside of rock outcrop, inside of hollow trees; any cavity that has temp higher than ambient
○ Method for most Vermont amphibians
72
Describe freeze tolerance
○ The ability to chill your body below freezing and survive
○ Most amphibians and reptiles CANNOT do this
§ Freezing is lethal because the formation of ice crystals physically damage cells and tissues
○ At least 4 species of frog and several turtles, lizards, and snakes CAN
○ Wood frogs (Lithobates sylvaticus)
§ Cell dehydrate, liver produces a glucose-based cytoprotectant
○ Allows for early breeding
73
What is aestivation?
○ Inactivity during prolonged periods of heat and drought
○ Death by dehydration occurs quickly
○ Some species retreat to deep burrows with high humidity and moist soils, become inactive and reduce their metabolism
○ Wester Spadefoot toad (Spea hammondi) spends >90% of their lives as inactive
74
How do amphibians regulate activity?
○ Needs: adjust activity based on favorable climates, to minimize risks, and synchronize physiology and behaviors
○ How? Biorhythms
§ Circadian rhythms (daily)
§ Circannual rhythms (annual)
§ Pineal organ (parietal eye)
□ Photoreceptor that helps with circadian rhythms
75
describe foraging in amphibians
○ Most are carnivores, but some herbivores
§ Carnivores = short digestive tract
§ Herbivores = long digestive tract
○ Extract energy and nutrients similarly to birds and mammals
§ Difference between the rate of food processing
○ Mammals process food 10 times faster
§ Not a handicap
□ Amphibian energy needs ~ 10 times less
76
Describe carnivory in amphibians
○ Most urodelans, adult anurans, all(?) caecilians
○ Diet typically restricted to invertebrates
○ Large frogs and salamanders occasionally eat vertebrates
§ Including members of their own species
○ Size of feeding structures related to size of prey
§ All adult frogs swallow their prey whole
§ Small prey = small head and narrow mouth
§ Large prey = broad head and wide mouth
77
Describe cannibalism in amphibians
○ Widespread, especially at larval stage
§ Usually associated with limited resources in pond
○ Asymmetrical
○ May develop specialized feeding structures and behaviors
§ Tiger salamanders and spadefoot toads
78
What are the benefits of cannibalism?
Energetic benefit
□ It conspecifics are easier to capture
May benefit from meal and elimination of competitor
79
What are the costs of cannibalism?
Genetic relative
□ Acting against genetic self-interest
Increased chance of contrasting disease or parasite
80
Are amphibians valuable bioindicators?
○ Collins & Crump (2009) argues that amphibians should not be help up as more sensitive early warning systems
○ Kerby et al. (2010): use of the canary metaphor for amphibians is done uncritically and is too commonplace. It is the job of scientists to be critical and not perpetuate generalizations that do not hold up to scrutiny.
81
What did the study in NH find about salamander biomass?
Salamander biomass exceeded bird biomass during nesting season
It was almost the same as small mammal biomass
82
What did Test and Bingham find?
Could not alter surface abundance with repeated surface removals
83
What did Traud find?
94% of salamanders distributed below mineral soil horizon (<12 cm)
84
Describe amphibian biomass in water
○ Estimates of ~500,000 per ha of wetland
○ One site in Georgia:
- 360,000 amphibian metamorphs in one year
- 1,400 kg of biomass
232,095 individual southern leopard frogs captured!
85
What do amphibians eat?
○ Amphibians are important, predators of vertebrates
- Larval salamanders can reduce mosquito larvae abundance
- Grazing tadpoles consume algae at amazing rates. Their loss can lead to overproduction of algae.
86
What eats amphibians?
○ Amphibians are important, stable prey resources for many predators:
- Plethodontids can make up to 60% of juvenile screech owl diets
- Tadpoles are the common, dominant prey of aquatic snake communities
□ And are eaten
Also important for nutrient cycling and moving materials between aquatic and terrestrial environments
87
What initiates reproduction?
Environment factors + nervous system + hormones
Ultimately, reproduction is triggered by environmental factors (temperature, rainfall, photoperiod)
88
What do hormonal changes cause?
Hormonal changes cause gametogenesis (formation of gametes)
89
What is reproductive activity synchronous with?
between the sexes
90
What are "Big Nights"
Predictable conditions in early springs: melting snow, temps >40F, warm rain
Highly synchronous
Widespread
Extremely high road mortality of stable, rare, and declining species
□ Usual suspects: wood frogs, spotted salamander, Jefferson's salamander, spring peeper, etc.
91
What are important for timing in reproduction in amphibians?
Temperature and rainfall are important for timing of reproduction; however, the asynchrony of reproduction among species at single localities tells us that these are not the only determinants
92
What are the breeding seasons of different Vermont herps?
Some late Winter breeders: Wood Frog
Some spring: spotted salamander
Some early to mid-summer: American toad
Some late summer: bullfrog
Some fall: marbled salamander (not in VT… or so we think)
93
How do some amphibians breed?
Most temperature zone species breed only once annually
Some breed every other year (dry or cold regions)
94
Describe the cloaca
the cloaca is a muscular cavity at the end of the large intestine though which digestive wastes, urine, and eggs or sperm leave the body
95
What is internal fertilization in salamanders?
Spermatophore (sperm packet) is produced by male cloacal glands, and is taken into the female's cloaca
Spermatophore is stored in spermatheca - a cloacal receptacle for storing sperm. Can be stored for days to months, depending on species
All salamanders (except hellbenders)
96
Describe internal fertilization in caecilians
As far as we know, all Caecilians use internal fertilization
The process differs from that described on previous slices
Male caecilians have a "copulatory organ" (phallodeum) that is inserted into the cloaca of the female, sometimes for more than an hour!
97
Describe external fertilization
Male releases sperm on the eggs as they exit the female
Most frogs, Cryptobranchid salamanders (i.e. hellbenders)
Process takes minutes to hours, depending on species
Amplexus - a behavior to reduce sperm competition
□ When the male clamps onto the female and does not let go
98
What is amplexus?
male grasps female and positions his cloaca near female cloaca. Many configurations
99
What are some other behaviors associated with mating?
Other behaviors - vocal, visual, tactile and chemical signals are used
Bring individuals together
Allows for mate choice
Enlarged limbs and nuptial pads may develop to aid in amplexing
100
What is the difference between an amphibian egg and an amniote egg?
○ Amniote egg has membranes that protect the embryo and are an adaptation for life on land
○ Amphibian eggs (generally speaking) are laid in water, and don't need a membrane to keep them from drying out
101
What is oviparity?
Females deposit eggs that develop and hatch in the external environment
Receive all their fetal nutrition from yolk within the egg. Has occurred independently in all three clades of amphibians
Most frogs and salamanders, some caecilians
102
What are egg masses used for?
IDing species
103
What is viviparity?
Eggs are retained in reproductive tract until development is complete
Rare in amphibians, but is seen in Caecilians, 9 Anuran species, and in some Urodelans in the family Salamandridae
104
What is metamorphosis?
The transformation of free-swimming larvae into adult forms
105
Describe the metamorphosis of caecilians
loss of external gills, development of lungs
106
Describe the metamorphosis of salamanders?
reabsorption of gills, tooth maturation, no major changes to digestive system
107
Describe the metamorphosis of frogs
Bone development, changes to skin, mouth changes, major changes to digestive system
108
What is direct development in amphibians?
No aquatic larval stage or metamorphosis; large eggs are deposited on land and the young develop inside the egg, emerging as fully formed but tiny versions of adults
Has occurred independently in all three clades of amphibians
In Vermont - one example: red-backed salamanders
109
What is nesting?
discrete structure constructed by a reproductive adult for egg deposition
110
What is the "Jeff Complex"
Unisexual females collect sperm from "pure" Jefferson or blue-spotted males
Sperm is used to stimulate egg development, and can either be discarded (hybridogenesis) OR can be incorporated into offspring genomes (increasing the ploidy levels of those offspring; kleptogenesis)
111
What is communication and why is it used?
The cooperative transfer of information from a signaler to a receiver
112
What is visual communication?
Visual: body movement or the flashing of a body part having a distinctive color or shape
113
What is tactile communication?
Tactile: one individual rubs, presses or hits a body part against another individual
114
What is chemical/pheromone/olfactory communication?
Chemical/pheromone/olfactory: chemical signals produce by one individual elicit a response in another
115
What is acoustic communication?
Acoustic: sound produced by vocal chords, rubbing body parts together, or slapping body parts against surface
116
What is the most important communication in herps?
Acoustic
○ Vocal communication is much more common in herpetofauna than previously thought
- Vocalization or sound production now documented in turtles, crocs, caecilians, snakes, tuataras, salamanders, and or course, anurans
- Now thought to be the ancestral state for tetrapods
○ Anurans are the posterchild for acoustic communication
○ Frog call surveys are therefore an important survey type for us to be aware of (more on other survey types coming up)
117
What is the importance of calling and sensory pollution
Male green frogs moved more and called less when artificial light was present
118
Why do we need to employ field methods?
○ Ultimately, to answer questions
- To understand an organism, we must be able to measure them in some way
119
What are the field method overarching considerations?
○ Research questions
○ Life history and species considerations
○ Detectability
○ Effort
120
What are some research questions?
○ What do you want to know?
- About which species?
○ Individual species
- Occurrence
- Relative abundance, recruitment, movement
○ Community
- Species richness
○ Other questions
- Disease occurrence, prevalence, or infection load
- Individual or population genetics questions
121
What is amphibian life history?
○ Complex life cycles that encompass multiple habitats
- Lots of choice in what to measure, where to conduct research
- Lots of decisions to make
- They all depend on the research question
122
What is detectability?
○ What influences our ability to successfully detect a species when it is truly present?
○ Organism characteristics
- Cryptic nature
○ Survey characteristics
- Seasonality
- Temperature and moisture
- Survey timing
○ Failing to account for detection can bias our results
123
What is effort?
○ Accounting for effort is essential
- It makes comparisons across sites/years possible and more meaningful
○ Time constrained
- Search for x number of minutes
○ Area constrained
- Search some predefined distance (whether a transect or other shape)
○ Both
○ Probably will be dependent on funding/personnel considerations
124
What is transect sampling?
○ Transects are placed
- Randomly or other
○ Generally, involve a visual encounter technique
- Walking a preselected line transect at night and counting all the salamanders seen
- Ex: 1 km stretch of potential amphibian crossing where amphibians are counted
125
What is point sampling?
○ Points are places (randomly or other) and generally involve a visual encounter technique
- Coverboard array, a pond/pool survey, etc. (area and/or time constrained)
- Ex: a coverboard plot where pieces of wood are flipped looking for red-backed salamanders
126
What are some general survey tips?
○ Active
○ Easy passive
○ Intensive passive
○ A few additional "add-on" methods
127
What are active searches?
○ What is it?
- An "active" search of habitat for your species of interest
○ Types:
- Transect, dip net, call, road search, egg mass, snorkel, electrofishing, etc.
○ Usually uses some kind of visual encounter protocol (i.e., counting animals [or egg masses] in some fashion)
128
What are active search: natural cover survey?
○ Turn cover objects in a habitat of interest
- Ex: in deciduous habitat for eastern red backed salamanders
- Ex: in streams for spring salamanders
○ Can be used for amphibian larvae or adults, depending on the habitat, species, and research question
○ Must record number of cover objects, length and width of transect searched, number of minutes, number of animals captured, etc. to help account for effort)
○ Cons: variation in counts could occur due to a number of things
129
What is active search: egg mass surveys?
* Search vernal pools or ponds and count all egg masses of various species by walking around the perimeter
- Conduct repeat surveys to help identify false negative errors and account for breeding phenology
* Cons: detectability issues, timing, observer training
130
What is active search: nighttime road survey?
* The most dangerous survey
* Safety is essential
- Lights, reflective gear, etc.
* Cons: bias estimates of abundance, sex rations, age distributions
131
What is active search: call surveys?
* Navigate to a point (random or other) and record all species heard calling
- Standardize surveys -- timing, weather, total listening time, etc.
- Conduct repeat surveys to help identify false negative and positive errors
* Cons: detectability issues, timing, observer training
132
What is easy passive sampling?
* Using human-made structures or loggers to monitor amphibians (traps that don’t physically trap animals)
* Types: artificial cover arrays, PVC pipes, litterbags, automated frog call loggers, environmental DNA
133
What is easy passive: coverboards?
* Artificial cover objects can be used to effectively sample terrestrial salamanders
* Primary method of SPARCnet (red-backed salamander research network)
* Cons: must allow boards to "season" for a month or so before use, potentially attracts other animals
134
What is Easy passive: Polyvinyl chloride (PVC) pipes
* Used for tree frogs, native and invasive (e.g. Cuban tree frogs in the southeast US)
* Cons: picky about configuration (size of PVC, placement, etc.)
135
What is Easy Passive: Automated Frog Loggers
* Record acoustic activity at specified times
* Can use machine learning algorithms to identify species (or human can listen to the recording)
* Cons: creates tons of data that must be reviewed, categorizing abundance difficult
136
What is intensive passive sampling?
* What is it
- Using traps to monitor amphibians (traps that do physically trap animals)
* Types: minnow traps (or similar), drift fences, pitfall traps
137
What is intensive passive: minnow/funnel traps
* Funnel-shaped construction allows amphibians to enter but not exit
- Mudpuppies, eastern newts, larval amphibians (sometimes breeding adults)
* Cons: traps can be expensive, and a systemic sampling design is key, can cause injury (sharp wire)
138
What is Intensive passive: drift fences?
* A fence (metal, cloth, plastic), usually combined with traps or funnels
- Can surround breeding ponds or be in movement zone
* Cons: labor intensive, small mammal "bycatch", daily checking essential
139
What is intensive passive: pitfall traps?
* A sunken receptacle that can be opened to capture wandering animals (usually in conjunction with drift fence)
* Cons: same as drift fence + rain, mesocarnivores, capture biases
140
What are combination surveys?
* Multiple survey methods are often used in conjunction
* Other data including collecting tissue samples for genetic work, disease sampling, or marking animals can happen in conjunction with these methods
141
How do you take basic measurements of amphibians?
* Snout-vent length (for all amphibians) and total length (for salamanders and tadpoles)
- Sometimes other measures (e.g., limb size) depending on the research question
142
How do you sex amphibians?
Sex (not binary for amphibians either!); sometimes not possible, depending on species and time of year
143
What is marking?
* Some kinds of questions require marking (or being able to ID) individuals
* What kind of questions?
- Survival and longevity
- Abundance
- Etc.
144
What are some marking methods?
* Toe-clipping
* Paint, sharpies, etc
* Passive integrated transponder (PIT) tagging
* Visual implant elastomer (VIE)
* Photo ID
* Etc.
145
What are the methods for getting a good technique for research?
* Understanding advantage and limitations is key
- Many limitations can be addressed using smart study designs and/or statistical methods
* No method can overcome a poorly thought-out research question
146
What are the world's most threatened vertebrates?
amphibians
147
What was the extinction of amphibians like between 1600-1970?
2 extinctions of amphibian species (0.07%) and only 2% of all amphibian species considered under threat -- lowest of any vertebrate group
148
What was extinction like by 2022?
40.7% of amphibian species under threat of extinction
612 (7.6%) critically endanger -- most of any vertebrate group
149
What is to blame for amphibian declines?
Amphibian declines and extinctions are a global phenomenon and follow patterns of global diversity
The causes of amphibian decline and extinctions are a global phenomenon and follow patterns of global diversity
The causes of amphibian declines are variable, often synergistic
150
What has land-use change done to amphibians?
* Habitat fragmentation can reduce access to complementary habitats and/or can isolate breeding ponds
* Habitat fragmentation can also cause direct mortality and/or impede movement
151
How has climate change affect amphibians?
Predictions vary by species, based on the sensitivity, exposure, and adaptive capacity
Consider: temp and moisture tolerances, disease spread, range shifts of competitors, hydrology, etc.
152
How has introduced species affected amphibians?
Competition
Predation
Hybridization
Disease reservoirs and vectors
Habitat modification
153
What are the emerging infectious diseases?
Trematodes
Iridoviruses (Ranavirsues)
Perkinsia
Chytridiomycosis
□ * B. dendrobatidis
□ * B. salamandrivorans
154
What are synergisms?
When multiple factors interact to create an effect that is larger than the independent sums of their parts
Many factors driving amphibian declines likely vary from location to location and are the result of multiple interacting factors
155
How do roads impact amphibians?
* Roads can have detrimental impacts on wildlife
- Reduced genetic exchange, behavioral changes, extirpation, etc.
* Even low traffic densities can lead to large amounts of mortality
* Wildlife-vehicular collisions will also increase without the implementation of mitigations strategies
156
What are wildlife underpasses?
* Most implemented mitigation technique used to prevent road mortality
Can be extremely expensive
Very few studies have compared pre- and post- construction mortality
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How do roads impact amphibians and their multiple life stages?
negatively
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What is a habitat matrix?
* Amphibians need both wetland and upland habitats
* Roads typically fragment these crucial amphibian habitats
- Mass mortality
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What is Monkton Road?
* Important and vulnerable amphibian crossing
* 1,000+ amphibians killed in two nights
* Monkton CC and conservation partners applied for conservation grants
- Built a series of underpasses
* Opportunity to collect data before and after construction
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What was the research question for the road study?
* Was there a significant decrease in amphibian mortality post-construction?
* Are they effective for arboreal amphibians?
Spring Peepers (Pseudacris crucifer) and Gray Treefrogs (Hyla versicolor)
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What were the survey methods for the road survey?
* Monitored five year prior to and seven years after construction
* Four to five surveys each year between late March and early May
* Primary data collected:
- Number of dead amphibians and weather characteristics
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What was the results pre- vs. post- construction?
* Significant negative difference post construction for non-arboreal amphibian mortality
- 94% decrease for non-arboreal amphibians
* No significant difference for arboreal amphibians
- 74% decrease in mortality for arboreal amphibians
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What was the conclusion of the road survey?
* Underpasses are effective at reducing amphibian mortality
- Not as effective for climbing species
* Should also benefit fall migration
- Important for population genetics
* Also benefits other taxa
