1

Darlo

st’s

Isla

nd M

ouse

D

RAFT

Spe

cies

Sta

tus A

sses

smen

t

U.S. Fish & Wildlife Service

July 2016

This draft SSA Report was completed using materials developed for the USFWS’ May 2016 Unified Listing Transformation (ULT) SSA Training Course, using a ficticious species, Darlost’s Island Mouse.

Darlost’s Island Mouse is the brainchild of Mr. Craig Hansen, R6 and Ms. Heather Bell, HQ, who developed all of the biological and ecological information on the species and the island so that students taking the SSA training could get a taste of how to assess a species status, using this transformative analytical framework. A huge thank you to Craig and Heather for their creativity and their significant time commitment to the development of the materials for this pilot course (a whole new species was born - squeak!).

We would also like to thank and recognize Janice Engle, HQ and Frank Muth for their substantial contributions to developing course materials and presenting this pilot SSA course.

ISLAND MOUSE (ZAPUS ISLANDSONIUS)

DRAFT SPECIES STATUS ASSESSMENT REPORT Note: This draft SSA report reflects the background biological and ecological information presented to students via the interactive on-line map, class handouts, and the exercises as filled out in the workbook by students, which was provided in the training. This draft SSA attempts to show how we could develop an SSA report from the materials used and developed in the training, however, it is incomplete and should not be viewed as representative of an SSA report. For examples of SSA reports, please go to the SSA google site: https://sites.google.com/a/fws.gov/ssa/

We indicate our Instructions for Report Development in [italics]. Where information is being utilized from the Species Status Assessment Class Exercise Workbook and other class materials, this is noted in ORANGE TEXT.

EXECUTIVE SUMMARY [Summarize the results of the SSA Here – BRIEFLY but CLEARLY]

Purpose of SSA: The purpose of the SSA is to assess viability of the species. The SSA describes viability of the species using the conservation principles of the representation, redundancy and resiliency. Viability is the ability to sustain populations over time; to do this, a species must have a sufficient number and distribution of healthy populations to withstand changes in its biological (e.g., novel diseases, predators) and physical (e.g., climate change) environment, environmental stochasticity (e.g., flooding, drought,), and catastrophes (e.g., sea level rise, increase in thunder storms). Viability is not a single state—viable or not viable; rather, there are degrees of viability--less to more viable or low to high viability. Generally speaking, the more resiliency, representation, and redundancy a species has, the more protected it is against the vagaries of the environment, the more it can tolerate stressors (one or more factors that may be acting on the species or its habitat, causing a negative effect), the better able it is to adapt to future changes, and thus, the more viable it is.

2

TABLE OF CONTENTS

Page:EXECUTIVE SUMMARY…………………………………………………………………………………………………………………………………….........2INTRODUCTION………………………………………………………………………………………………………………………………………………………3SPECIES’ TAXONOMY………………………………………………………………………………………………………………………………………………3SPECIES’ ECOLOGICAL NEEDS……………………………………………………………………………………………………………………………….…3

Historical Range and Distribution………………………………………………………………………………………………………………5Life History………………………………………………………………………………………………………………………………………………..6Habitat…………………………………………………………………………………………………………………………………………………….10

INDIVIDUAL NEEDS…………………………………………………………………………………………………………………………………………………11POPULATION NEEDS………………………………………………………………………………………………………………………………………………12

Population Resiliency Needs Analysis…………………………………………………………………………………………..............12

Population Resiliency Needs – Summary……………………………………………………………………………………………….…16SPECIES NEEDS……………………………………………………………………………………………………………………………………………………….17REPRESENTATION…………………………………………………………………………………………………………………………………………………..17

Summary of Representation Needs……………………………………………………………………………………………………….…19REDUNDANCY………………………………………………………………………………………………………………………………………………….…….19

Summary of Redundancy Needs………………………………………………………………………………………………………………21CURRENT CONDITION……………………………………………………………………………………………………………………………………………23

Summary of Current Condition………………………………………………………………………………………………………………..23Methods…………………………………………………………………………………………………………………………………………….…….23Cause and Effects – Assessing Reasons for Current Condition………………………………………………………………….25Description of Stressors/threats………………………………………………………………………………………………………….……25Summary of Overall Current Condition……………………………………………………………………………………………….……30Uncertainty……………………………………………………………………………………………………………………………………………...32

SPECIES’FUTURE CONDITION AND STATUS…………………………………………………………………………………………………………….33Introduction and Summary………………………………………………………………………………………………………………………33Methods…………………………………………………………………………………………………………………………………………….……33Description of Future Scenarios……………………………………………………………………………………………………………….33Assessment of Future Condition of Each Population…………………………………………………………………………..……34Methodology……………………………………………………………………………………………………………………………………………38Species Future Resiliency, Redundancy and Representation…………………………………………………………………….40

CONCLUSION FOR SPECIES VIABILITY……………………………………………………………………………………………………………………..40

LITERATURE CITED

APPENDICES

List of Figures

List of Tables

3

INTRODUCTION [The Introduction sets the stage for the biology discussion to begin]

o The Island Mouse (Zapus islandsonius) Background Fact Sheet

Chuck Darlost, self-proclaimed British naturalist and explorer, first described the Island mouse ( Zapus islandsonius) in his journal entries written after he was lost at sea from the H.M.S. Beagle, on which his uncle, Charles Darwin, was also a passenger. After his nephew Chuck fell or was forced overboard, Charles Darwin continue his successful voyage to the Galapagos Islands, while Darlost remained lost on the then undescribed and sparsely inhabited Darlost’s Island, until his death approximately 20 years later.

In his journal, Darlost described how he washed ashore Darlost’s Island sometime in September 1835. Darlost immediately noted large numbers of unusual, gray-colored mice with long tails, big ears, large hind feet and prominent incisors, which he called Darlost’s Island mouse. Darlost observed how the mice ate dine beetles (Cicindela abyssima) on the sandy beaches, nested in dense grasses on the upland plains, and were especially sensitive to loud noises and temperature extremes.

Darlost described all 10 populations of Island mice distributed across the 3 different habitat types on the island. Darlost noted the thicker coats of the two Mountain populations, the annual migrations of one of the four Coastal populations, and the secluded nature of the four populations living in the forested (Paradise Palms) habitats. Darlost also described mortality from loud noises, volcanic gases, exposure, predation, and collection by the native islanders. Darlost’s rudimentary studies also correctly determined that all populations have approximately 2 to 3 young per litter, that adults live up to 5 years, that both males and females care for their young, that breeding occurs in the early summer and is most successful when temperatures are warm, food is plentiful, and the soothing sound of waves is the only noise. Darlost estimated that there were at least 500 Island mice in both the coastal habitats of the Message in a Bottle and Beach Bums Beaches. Darlost also introduced Darlost’s Fire to the island, a bacterial skin disease that thins the coat and increases exposure in infected Island mice.

Although Darlost was the first British explorer to describe the Island mouse, the native islanders had studied and appreciated the species for at least 100 years before Darlost washed ashore. Petroglyphs carved in the stone walls of caves depict rodents with prominent ears and hind feet, and dead island mice near exploding coconuts and thunderstorm clouds. Native residents of Cannibal Cove continue to prize and collect Island mice to make ceremonial garments and souvenirs, which are sold to tourists.

This Species Status Assessment (SSA) reviews the ecological needs of the Island mouse, at the individual, population, and species level; population and species ecological needs are expressed using conservation biological principles of Representation, Redundancy and Resilience. This SSA analyzes the current condition of the species, including how past threats, combined with current threats on the landscape have affected the status of the species today. Finally, we consider how climate change, together with anticipated threats, may affect the species in the future, using several plausible scenarios.

SPECIES’ TAXONOMY[Not provided in SSA training, but this section should be considered, if taxonomy is not covered in another recent document that you could cite]

SPECIES’ ECOLOGICAL NEEDS4

[Summarize here, and discuss in more detail later]

Island mice are currently known to occur in 10 populations on Darlost Island, which is relatively ecologically and geographically diverse (from mountains which are high elevation to low elevation coastal plains). One population (a mountain population) has been extirpated. Beachgrass, dune beetles, are key resources for Island mice in all of the habitats in which they occur (Coastal Plains, Paradise Palms and Mountain habitats). One population is a sink (The Castaways) as is does not reproduce, and one population is physically isolated (Treasure Grove), though limited immigration does occur.

There is some immigration and emigration between Island mice populations; particularly notable is a 20 mile migration by one population (The Beach Bums) across extreme habitat (the Darlost Desert), apparently assisted by the use of cocktail umbrellas; researchers have long noticed discarded cocktail umbrellas at the entrance to the Realm of Spirits population from the Beach Bum’s northern wintering. Another unique method of immigration for this species is via Jack sparrow mouse-drops. Telemetry studies have documented Jack sparrows snatching up mice from the Message in a Bottle population and occasionally dropping them either into the Misty Mountains population or Treasure Grove Population.

The Island mouse relies primarily upon dune beetles for food. Dune beetles are herbivores (plant eaters), feeding on decaying beachgrass and other decomposing vegetation. Female beetles lay their eggs in small depressions in the sand. Dune beetle eggs over-winter in their sandy depressions, hatch in the spring, and by early May, the yearling beetles disperse across Darlost’s Island and fly to Castaway Island.

Island mice also eat the seeds and stalks of beachgrass and use beachgrass clippings to construct their nests. Despite its name, beachgrass grows throughout Darlost’s Island, including in the understory of the Paradise Palm habitats and in the interstitial spaces between rocks on the mountains. Both males and females clip live beachgrass with their incisors and weave the clippings into an enclosed, oval-shaped nest, typically placed at the base of live beachgrass or other vegetation. Additionally, Island mice typically rely on beachgrass to shelter from excessive heat and cold, and to hide from predators. In the Mountains, mice use the interstitial spaces between rocks and boulders to hide their nests and stay warm.

o Island Mouse: Resources, The Island Mouse Background Fact Sheet

HISTORICAL RANGE AND DISTRIBUTION[Describe where species exists now, historical data, etc.]

o The Island Mouse Background Fact Sheet (colored)o Interactive map, individual Island Mouse Population Fact Sheets

The Island Mouse occurs in 10 populations across three habitat types on Darlost Island.

There are four populations on the coastal plains, which occupies 50 percent of Darlost Island: The Beach Bums, Message in a Bottle (MIB), Cannibal Cove and Castaways. The Castaways are a small sink population stranded on Castaway Island, an ephemeral sandbar formed by sedimentation that collects as Darlost’s Island’s snowmelt-fed southern river flows into the ocean. The Message in a Bottle (MIB) population is located on the Island’s westernmost beach, in the shadow of the Misty, Skull and Darlost’s Dome Mountains. The Cannibal Cove population is the closest population to Skull Mountain, which is volcanically active. The Beach Bums population is located on the Islands largest and flattest eastern coastal plain, which occupies approximately 50 percent of the Island.

There are four populations in the forested mid-elevation, Paradise Palm habitat: Snowmelt Thicket, Deadman’s Dunes, Treasure Grove and Realm of Spirits. The Snowmelt Thicket population is west of the river, and Deadman’s Dunes is located to the east of the river; a sandy transitional zone separates Deadman’s Dunes from the Beach Bums population. These populations are located south of the Mountains (Misty, Skull, and Darlost’s Dome). Treasure Grove is isolated by Misty and Skull Mountains directly to the west and on the east by the snowmelt fed

5

river. The Realm of Spirits population is located across the river from Treasure Grove, and is separated from the coastal plains Beach Bums population by Darlost’s Desert.

There are two populations in the high elevation mountains: Darlost’s Dome and Misty Mountain. One mountain population, Skull Mountain, is extirpated. The two mountain top populations are relatively isolated.

The figure below shows the distribution of Island mouse populations across Darlost’s Island.

Figure 1. Island Mouse populations, by Ecosystem

LIFE HISTORY o Exercise 1 Life Cycle conceptual diagram and table (add clarifying text as necessary)o The Island Mouse Background Fact Sheet (colored)o Island Mouse Resources Fact Sheeto Individual Island Mouse Population Fact Sheets (located on interactive map)

Darlost’s Island Mouse occurs only on Darlost Island, located somewhere in the Pacific Ocean, near the Galapagos Islands. The Island mouse is gray in color, has a long tail, big ears, large hind feet and prominent incisors. The mouse feeds primarily on dune beetles (Cicindela abyssima), nests and shelters primarily in dense beachgrasses or interstitial spaces between rocks and boulders, and are especially sensitive to loud noises and temperature extremes. Darlost’s Island Mouse adults live up to 5 years. Breeding occurs in the early summer and is most successful when temperatures are warm, food is plentiful, and the soothing sound of waves is the only noise; pairs have two litters per year, and have approximately 2 to 3 young per litter and both males and females care for their young. In the text below, we note where individual populations diverge from the general life history presented here.

Dune Beetles are the primary food source for Island mice. While dune beetles live in all of the Island’s habitat types, population are most concentrated along the four coastal beaches where female beetles lay their eggs in

6

small depressions in the sand. Dune beetle eggs over-winter in their sandy depressions, hatch in the spring, and by early May, the yearling beetles disperse across Darlost’s Island and fly to Castaway Island.

Dune beetles are herbivores (plant eaters), feeding on decaying beachgrass and other decaying vegetation. Numbers of dune beetles increase during et years when vegetation is more plentiful, but the beetles do not swim well and often drown in deep water. Additionally, adult beetles die when the ambient temperature drops below 80 degrees farenheight, particularly every year when the cold winter trade winds cause temperatures to drop along the Beach Bum coast. This beetle die-off in the winter motivates the Beach Bum population to migrate to the northern coast, and the Beach Bums frantically feed (hyperphagia) on dune beetles prior to this 20-mile migration. During the breeding season, male Island mice hunt for dune beetles and bring prey back to the nest to feed the whelping (nursing) female.

The species occurs in 10 populations distributed across three habitat types: the flat coastal plains (4 populations), forested mid-elevation Paradise Palm habitat (four populations) and high elevation Mountain habitat (2 populations).

Coastal Populations

One coastal population is located on an ephemeral sandbar, separated from Darlost’s Island and is considered a population sink (Castaway Population). Each spring from late March to early May, the cold trade winds subside and signal the return of warmer temperatures across Darlost’s and Castaway Islands. Spring temperatures quickly thaw the three snowcapped mountains and Darlost’s Island’s two rivers begin to flood, souring vegetation and drowning or washing away Island mice from the four Paradise Palms populations. The floods last for approximately two weeks and wash away 50 to 100 mice from the Snowmelt Thicket population and approximately 10 mice from the Dead Man Dunes population into the ocean and out toward Castaway Island. The Castaways population is composed entirely of Island mice from the Snowmelt Thicket and Dead Man Dunes populations. Lack of detection of nests via Satellite imagery indicates an uncertainty about success of reproduction. Cold trade winds return in mid-October, drying the beachgrass and killing the dune beetles, and by early November, the entire population succumbs to starvation and exposure to cold temperature below 80 degrees F.

The Beach Bums population is the only population of Island mice that migrates long distances every year. The cold tradewinds begin to blow from the northeast in early November, forcing the Beach Bums to migrate approximately 20 miles across Darlost’s Desert to warmer coastal habitats on the Island’s northwest coast. The trade winds not only cause ambient temperatures to drop below 80° F (27 ° C), but the winds dry the beachgrass that provides food, cover from predators, and nesting material, and coincide with the last die-off of dune beetles before winter. Prior to the beachgrasses and dune beetle die-off, the Beach Bums accumulate fat (hyperphagia) by consuming large volumes of dune beetles. The Beach Bums begin their migration in mid-to-late October and arrive on their northern wintering grounds by early November. Beach Bums that do not migrate north typically die from exposure to cold temperatures and from a lack of food and cover, although some stragglers have been known to seek refuge in the palms of the Dead Man’s Dunes located to the west. It’s unclear how many Beach Bums emigrate to the Dead Man’s Dunes instead of migrate, although approximately 30 juveniles from the Dead Man’s Dunes are enticed by a seemingly carefree, beach lifestyle and become Beach Bums every year.

Figure 2. Migration pattern of The Beach Bum Population

7

During both the winter and spring migrations in November and May respectively, approximately 50 percent of the Beach Bum population is lost to exposure in Darlost’s Desert. Darlost’s Desert is hot and dry, ambient temperatures often exceed 100° F (38° C), and the sandy dunes provide little cover or food for migrating Island mice. The 20-mile journey takes roughly two weeks, and the Beach Bums arrive on the northeast coast by late November. During the winter, some Beach Bums breed and nest, although less than 10 percent of the young born during the winter survive the springtime migration south because they have not fully matured prior to the migration. Additionally, some Island mice from the neighboring Realm of Spirits join the Beach Bums, although the impact of this emigration on population size is unknown, although totals are likely similar to emigration from the Dead Man’s Dunes population. Despite migration losses, recent survey data collected over the last five years indicates that over-migration mortality has dropped from 50 percent annually, to less than 25 percent annually. It’s unclear why the population losses during migration have decreased, although the decrease coincides with an increase in tourism on the southern coast and an increase in the number of anecdotal reports that migrating Island mice carry discarded cocktail umbrellas.

The Cannibal Cove population, located to the south of the MIB population in the shadow of Skull Mountain, is unique in that these mice always have three pups per litter, compared to the usual two to three in the other populations. During the winter, from November to May, tradewinds force Skull Mountain’s toxic gas plume over Cannibal Cove and kills mice if they are unsheltered by huts and cabanas (thanks to the native islanders in Cannibal Cove).

The MIB population, located on the Island’s westernmost beach, is one of the most “robust and hardy” on the Island (cite Chuck Darlost Journal). This is the only population that suffers from Darlost’s Fire, an disease introduced to the Island by its first European visitor (Chuck Darlost); this disease thins the coat of MIB mice, provides a pinto coloring, increases the risk of exposure to cold temperatures, and increases collection (tourists prize the pinto pelts).

Paradise Palms populations

One Paradise Palms (mid-elevation) population, Treasure Grove, is geographically isolated from other populations, but is self-sustaining, via immigration from the MIB via Jack’s sparrow. A telemetry study (cite here) revealed that MIB mice snatched by Jack’s sparrow were dropped into Treasure Grove’s forested canopy, as well as other locations, including the top of Misty Mountain. Despite the geographic isolation, the Treasure Grove mice are the most genetically similar to the MIB population, and the least genetically similar to The Realm of Spirits population, just across the river to the east.

The Realm of Spirits population is flanked by a large river to the west and the Beach Bum’s northern beach to the east. The river floods during the spring from snowmelt, but The Realm of Spirits mice are able to climb to higher ground to escape drowning or being washed out to sea. The Realm of Spirits receives a regular influx to its population via the winter migration of The Beach Bums; approximately 50 Beach Bum mice emigrate to The Realm of Spirits each winter before the Beach Bums head south in the spring. Realm of Spirits mice feed on shards of cracked coconuts that fall to the ground from the Paradise palms. However, the loud explosions from falling coconuts are a significant source of mortality from cardiac arrest, killing approximately 25 percent of the population each year.

The Dead Man Dunes population is flanked by the river that separates it from the Snowmelt Thicket population. These two populations are affected each year by the floods that occur each spring. The Snowmelt Thicket population is more negatively affected, with 50 – 100 mice being washed out into the ocean towards Castaway Island. Dead Man Dunes loses about 10 individuals each year. Dead Man Dunes population has the lowest fecundity of any Island mouse population due to their antagonistic, intraspecific behavior. As a result of this low fecundity, loss to floods and emigration to Beach Bum population, Dead Man Dunes has a declining population trend.

The Snowmelt Thicket population, located east across the river from Dead Man Dunes population seem to be less adapted to the regular spring floods, losing up to half its population each year. In the shadow of Skull Mountain, the Snowmelt Thicket mice dig burrows in the forest floor to escape the toxic fumes that are blown into the area by the cold winter trade winds, November to May.

8

Mountain populations

Mountain populations are isolated and have small population sizes. These mice are uniquely adapted to their mountain habitat, using the interstitial spaces between rocks and boulders to hide their nests, escape Jack’s sparrow and stay warm if mountaintop temperatures drop below 80 degrees F. Due to their colder, high elevation habitats, Mountain Island mice have thicker, darker pelts.

Misty Mountain population is small, isolated and at risk; Jack’s sparrow, toxic gases from Skull Mountain, cold temperatures, collection, low food availability and small population size are potential problems for mice living in Misty Mountain’s extreme, high-elevation habitats.

The Darlost’s Dome mountain population is similar to the Misty Mountain population, but its fur is light brown in color, due to the warmer temperatures and lower elevation of their mountaintop habitats compared to those on Misty Mountain.

Genetic analyses reveal that approximately 1,500 years ago the two Mountain populations were connected as one population, but became isolated following an eruption from Skull Mountain that widened the valley separating the two mountains. The valley now acts as a complete barrier to genetic exchange between the two populations. The genetics analyses reveal that the two populations have been isolated for hundreds of years. The small population sizes continue to be of concern.

Species Life History

Island mice hunt and eat the dune beetle, a fleshy, winged insect that provides high quality fats, proteins, and water. The dune beetle lives in all of Darlost’s Island three habitat type, but populations are most concentrated along the four coastal beaches, where female beetles lay their eggs in small depressions in the sand. Dune beetle eggs over-winter in their sandy depressions, hatch in the spring, and by early May, and the yearling beetles disperse across Darlost’s Island and fly to Castaway Island. Dune beetles are herbivores (plant eaters), feeding on decaying beachgrass and other decomposing vegetation. Numbers of dune beetles increase during wet years when vegetation is more plentiful, but the beetles do not swim well and often drown in deep water. Additionally, adult beetles die when the ambient temperature drops below 80°F, particularly every year when the cold winter trade winds cause temperatures to drop along the Beach Bum coast. During the breeding season, male Island mice hunt for dune beetles and bring prey back to the nest to feed the whelping (nursing) female.

Island mice are long-lived; adults live up to 5 years.

Island mice have approximately 2-3 young per little, and breed twice per summer, between June and September. Reproduction is more successful when food is plentiful, temperatures are warm and the only sound is the soft, soothing sound of waves lapping against the coastal beaches. Both males and females care for their young. Pups mature and leave the maternal next within three months. Survival rates of young average 75%, with natal losses due to predation by Jack’s sparrow and exposure to cold temperatures.

Island mice eat the seeds and stalks of beachgrass and use beachgrass clippings to construct their nests. Despite its name, beachgrass grows throughout Darlost’s Island, including in the understory of the Paradise Palm habitats and in the interstitial spaces between rocks on the mountains. Both males and females clip live beachgrass with their incisors and weave the clippings into an enclosed, oval-shaped nest, typically placed at the base of live beachgrass or other vegetation. Additionally, Island mice rely on beachgrass to shelter from excessive heat and cold, and to hide from predators.

Island mice in Paradise Palm habitats are more reclusive; Coastal populations are more adapted to humans.

9

Figure 3. Life cycle of Island mouse

(This figure is representative of students’ work in Exercise 1 of the Darlost’s Island Mouse SSA Exercise Workbook)

Table 1: Life cycle Table, by life stage, for Island mouse

HABITATo Same fact sheets as above

The Island Mouse populations are distributed across three habitat types: the flat coastal plains (4 populations), forested mid-elevation Paradise Palm habitat (four populations) and high elevation Mountain habitat (2 populations).

Beachgrass grows throughout Darlost’s Island, including in the understory of the Paradise Palm habitats and in the interstitial spaces between rocks on the mountains. Island mice eat the seeds and stalks of beachgrass and use beachgrass clippings to construct their nests. Both males and females clip live beachgrass with their incisors and weave the clippings into an enclosed, oval-shaped nest, typically placed at the base of live beachgrass or other vegetation. Additionally, Island mice rely on beachgrass to shelter from excessive heat and cold, and to hide from predators.

The Coastal Plains are flat plains and sandy beaches on the eastern, southern and western sides of the island. There are four main coastal beaches on Darlost’s Island.

10

The mid-elevation forested Paradise Palm habitat occurs at the northern and southern coasts, along two large rivers; the northern river geographically separates the Treasure Grove population from the Palm habitat occupied by The Realm of the Spirits population on the inland side. A second river bisects the Island from the north, southward all the way the sea. At the southern end, Paradise Palm habitat supports two more populations, Snowmelt Thicket and Dead Man Dunes. Paradise Palm habitat consists of thick forest of coconut palm tree, with an herbaceous understory, including Beachgrass. Paradise Palm habitat provides an additional food source (coconuts) for Island mice, which can be eaten when the fruit falls to the ground and is cracked. However, the exploding coconuts hitting the ground also represent a stressor for mice, as they can suffer spontaneous cardiac arrest from the noise.

High elevation Mountain habitat on Darlost’s Dome and Misty Mountain is characterized by a rocky, barren substrate, beachgrass in the interstitial spaces, colder temperatures, and exposure to the misty haze of the toxic gas plume wafting from Skull Mountain (particularly Misty Mountain). Skull Mountain is volcanically active, but does not currently support a population of Island mice, though at one time it once supported a large population that was likely identical to the Misty Mountain population. Skull Mountain erupted in the late 18 th century and extirpating the only population of Island mice that existed.

INDIVIDUAL NEEDS Resource Needs and/or Circumstances by Life Stage in support of individual fitness

o Exercise 2 (Table of resource needs by life stage); [include table here and develop text if necessary]

Conceptual Model of life stages (From Exercise 1) [Additionally, could develop conceptual model of resources needed by each lifestage]

Present uncertainty (data gaps, linguistic, etc.)

Individual resource needs are listed in the Table found in Exercise 2; the most important resources needed by individuals include:

Dune beetles (Feeding, Breeding) Interstitial spaces (Shelter) Beachgrass (seeds, stalks, decaying) ( Breeding (nesting), Shelter, Feeding) Soothing wave sounds (Breeding) Low ambient noise (< 60 decibels) Breeding, Feeding, Shelter

Examples of Resource Needs by Life Stage:

Pups - Nestlings

Cover for grassy nest (beachgrass, rocks) Nest (beachgrasses) Healthy nursing female (beetles brought by mates, seeds) Warm temperatures

Pup – Juveniles

Beachgrass (Cover for protection) Beachgrass Beetles Coconuts Dispersal corridors Warm temperatures

Adults

Beachgrass, seeds, stalks, decaying Dune beetles

11

Rocky substrate Interstitial spaces Soil (friable) (for burrowing) Low ambient noise (< 60 decibels) Soothing sounds of waves Migration corridors (upland areas) Cocktail umbrellas Warm temperatures

POPULATION NEEDS Describe Population Needs for Resiliency

o Ecological setting of population, population structure information from Exercise 3, Questions 1 and 2. [Summarize for all populations (suggest table format)].

o Individual Island Mouse Population Fact Sheets (located on interactive map)o Conceptual model of population needs at the Ecological Setting level (Part 3 of Exercise 3, page

5) [Think about what is needed, in terms of demographic and habitat parameters for population “health”?]

Resiliency is the ability to sustain populations in the face of environmental variation and stochastic events. Each population of Darlost’s Island mouse was evaluated for overall population health and fitness, or resiliency, as measured by selected habitat and demographic factors. Table 2 provides an example of the table that was completed for all 10 populations.

Table 2: Population Needs

Example of table that was completed for each population in the Training (Exercise 3, Part 4)

Population Name: Realm of Spirits (Paradise Palms Ecological Setting)Population Structure: metapopulationAbundance and Demographics:

# individuals Gender ratio Age distribution other

Distribution: Distance Connectivity Area occupied (if known) other

Habitat Quality/Quantity

Minimum viable population - >= 100

1:1 sex ratio?

Connectivity to Beach Bums population via Darlost’s Desert (winter, spring)

20 miles may be maximum migration distance

Juvenile dispersal < 20 miles

Adequate Quantity and quality of:

Beachgrass, Dune beetles Low ambient Noise (<60

decibels) Warm temps (80 – 100

degrees F) Soothing wave sounds

Uncertainties: Assume 1:1 sex ratio since both parents are involved in caring for young. Unknown juvenile survival rate; unknown dispersal limit Unknown habitat quality (of beachgrass) Unknown quantity of beachgrass needed

Describe the stochastic events these populations are likely to experience (environmental, demographic, and genetic), based on the historic and evolutionary context.

o Island mice Paradise palm populations can expected to be subjected to regular spring flooding of both Island Rivers that results in 25-50% population mortality in some populations.

12

o The Misty Mountain, Cannibal Cove, Snowmelt Thicket, Dean Man Dunes populations can expect occasional exposure to toxic gas fumes from Skull Mountain, which results in significant mortality.

o The cold Trade winds that blow from the northeast in early November, force the Beach Bums to migrate 20 miles across Darlost’s Desert to warmer coastal habitats; 50% of the Beach Bums population is lost to exposure in Darlost’s Desert each year due to the extreme temperature and lack of cover (> 100 degrees F).

o Beach Bums that do not migrate die from exposure to cold temperatures and lack of food and cover.

o Conceptual Models of Resiliency from Exercise 3, Part 3 with text as necessary, informed by Question 4 of Exercise 3

o Table by population (of circumstances and resources) from Exercise 3o Individual Island Mouse Population Fact Sheets (on interactive map)o Island Mouse Threats Fact Sheeto Island Mouse Background Fact Sheet (colored)o Exercise 8: Population Resiliency

Summary of Resiliency Needs

Habitat and demographic parameters important to population health were identified for each population (see example Table 2 above). We selected demographic and habitat parameters that could be measured or that best represented species needs for resilience. Demographic parameters that were selected to represent resiliency needs included: Abundance, Population Growth (Adult survival, Juvenile survival, Fecundity, trend) and genetic diversity. Habitat parameters included: Beetle abundance, Beachgrass, and Cover.

A conceptual model articulating the resiliency needs of each ecological setting was developed (see Figures 4-6 below).

o Present Conceptual Models (for each ecological setting) from Exercise3

Figure 4: Coastal Ecological Setting Resiliency Needs Conceptual Model

13

Figure 5: Mountain Ecological Setting Resiliency Needs Conceptual Model:

14

Figure 6: Paradise Palms Ecological Setting Resiliency Needs Conceptual Model

15

Population Resiliency Needs – Summary

In general, we depict population resiliency for Darlost’s Island mouse below, in Figure 7:

Resiliency for Darlost’s Island mouse requires healthy populations across the range of ecological settings on the Island, including the Coastal Plains, Paradise Palms, and Mountain habitats; healthy populations are sufficiently large (>= 100 individuals), have a positive growth rate (including adequate adult, juvenile survival rates and adequate fecundity), and sufficient immigration occurs to ensure connectivity between populations such that genetic diversity is ensured. Additionally, beetle abundance is sufficient and sufficient quantity of high quality habitat that provide food resources and cover, including beachgrass, friable soil, and interstitial spaces, that are free of, or have manageable, threats.

Current uncertainties and unknowns that we have include:

MVP >= 1: While there is generalized information from one well studied population (The Beach Bums) and Cave Petroglyph data (see Caves on Interactive Map), Misty Mountain’s Population of 50 individuals brings this MVP number into question. Further research would be needed to see if the Misty Mountain is exhibiting any deleterious effects (genetic drift for example) from their smaller population size. However, the resiliency of a population of 100 is much greater than that for a population of 50, especially given the types of stochastic events on the island.

A sufficient population growth rate is unknown. A sufficient adult mouse survival rate is unknown. The juvenile survival rate is unknown. The sex ratio needed for sufficient reproductive success is assumed to be 1:1 due to both parents caring

for young, but this has not been documented in the literature. The quantity of habitat area is unknown (what is the necessary “patch” size?) Carrying capacity – we are do not know what habitat area is needed for what population size.

16

Quality of habitat needed – though we know that beach grass, friable soils, interstial spaces of sufficient quality are needed, we are unable to define the quality of these habitats more specifically, beyond the generalities of present ambient temperatures (80-100 degrees, current amount of precipitation, etc.).

Area of occupation for populations is currently unknown. Connectivity requirements (amount of genetic exchange) – Movement between populations is essential

for genetic health via gene flow and we know that genetic exchange currently occurs between various populations via sparrows, migration, emigration, and perhaps other mechanisms, but the amount of exchange necessary is unknown.

SPECIES NEEDS REPRESENTATIONRepresentation describes the ability of a species to adapt to changing environmental conditions. Measured by the breadth of genetic or environmental diversity within and among populations, representation gauges the probability that a species is capable of adapting to environmental; it is the evolutionary capacity or flexibility of the species. Representation is the range of variation found in a species, and this variation--called adaptive diversity--is the source of species’ adaptive capabilities.

Methodology o Describe process for determining representation needs of species [i.e. describe the rationale for

describing representative variation for the Island Mouse, including geographic, genetic, morphological, behavioral, and ecological variation and why the factor(s) were or were not considered.]

Considering the Mouse is localized endemic species limited to a single island geography with varied habitat types within which island mouse populations are distributed, we will use the major ecological settings of coastal plains, paradise palms and mountain habitats as representative areas. Within each representative ecological setting, we will also consider other important variations, including morphological, behavioral and genetic factors that may be indicative of the species adaptive capacity.

Describe distribution of populations

Darlost’s Island Mouse populations are distributed throughout the Island’s three main ecological settings (See Figure 1). There are 4 populations in the Coastal Plains ecological setting, 4 populations in the Paradise Palms ecological setting and 2 populations in Mountain habitat (1 Mountain population is known to be extirpated). In addition to this ecological setting variation, the Island Mouse demonstrates variations in behavior, morphology and genetically that may indicate differences in adaptive capacity for different populations (See Table 2).

o Include the map (see Exercise 4) of species range and population distribution, as a way to show and discuss representation [describes the number of populations and their distribution within and across ecological settings, and explain in text].

Figure 8: Population Distribution on Darlost Island within Ecological Settings17

Further describe important life history variation, such as variation in ecological setting, behavior, morphology, genetics, etc.

o Use Table of Representative Variation from Exercise 4o Individual Island Mouse Population Fact Sheets

Table 2: Representative Variations, by Ecological Setting

18

Summary of Species Needs - Representation

Island mouse representation is described as having healthy populations widely distributed across the three ecological settings and which include the range of morphological (pelt coloring, thickness), behavioral (migratory, use of tools such as umbrellas, cabanas, wood), and genetic variation, which is indicative of the species’ ability to adapt to changing environmental conditions.

REDUNDANCYRedundancy describes the ability of a species to withstand catastrophic events. Measured by the number of populations, their resiliency, and their distribution (and connectivity), redundancy gauges the probability that the species has a margin of safety to withstand or can bounce back from catastrophic events; combined with resiliency and representation to form the three-pronged biodiversity principles.

Methodologyo Describe process for determining species need for redundancy [consider exposure to

catastrophic events, dispersal of populations, etc.]

Representation needs for this species is being considered primarily through consideration of the three main ecological settings on the Island (Coastal Plains, Paradise Palms and Mountain habitat). Within each area of representation, there should be redundancy of populations to withstand catastrophic events.

Catastrophic events that could affect this species include:

Spring flooding events Disease (Darlost’s Fire, new disease) outbreak (beyond MIB) Volcanic eruption Hurricanes Beetle/Beachgrass die off Temperature change Drought Oil spill Ship wreck Tsunami Military training

19

o Exercise 4 Redundancy Questions Identify demographics (meta population needs), connectivity in support of redundancy and

representation [create a table, but include text as necessary]o Interactive Mapo Individual Island Mouse Population Fact Sheets o Exercise 4 Redundancy Questions

Figure 9: Species distribution and known migration/immigration

Populations are dispersed over different elevations across the island (sea level Coastal populations to Mountain populations), some with different temperature tolerances and some are isolated (Treasure Grove)

Behavioral and morphological differences may reflect a capacity to adapt to changing conditions and thus these are important characteristics for the species.

Populations have many behavioral differences that may provide advantages during different future events (Flooding, increase in ambient temperature, increase in human presence, etc. . .)

Surfing (The Snow Melt Thicket population) Use of Umbrellas as shade during migrations (the Beach Bums Populations) Tree climbing (Realm of Spirits population – Paradise Palms) during spring River Flooding Reclusiveness/antagonistic behavior (Dead Man Dunes) Other variations

Summary of Species needs in terms of Redundancy

20

Redundancy for Darlost’s Island Mouse is multiple healthy populations with sufficient connectivity that are distributed across the three ecological settings within the Island landscape sufficient to guard against catastrophic events that could eliminate portions of the species adaptive diversity and that reflect variation in geographic distribution and behavior ( see Figure 10).

Figure 10: Conceptual Model of Island Mouse Redundancy

Uncertainty (data gaps, linguistic, etc.)

While connectivity between populations to ensure genetic diversity of the species is essential, it is unknown how much connectivity is needed, and between which populations. Further study is needed.

21

CURRENT CONDITION

22

SUMMARY OF CURRENT CONDITIONIn this chapter, we first describe the trend of Island mouse populations (by graphing population numbers over time) and then we assess other demographic and habitat factors. We describe and rate the stressors that most affect the species. Finally, we developed a qualitative categorical scale for population resiliency and then scored each population according to this scale to come up with an overall rating of current condition for each population.

METHODS [describe how the current condition of each population was assessed]

First, we assessed demographic and habitat data for each population and included that data in a table. An example is included as Table 3, below. We then developed logic chains and influence diagrams to help assess anthropogenic and human factors that may be influencing Island mouse populations. Our modeling allowed us to identify the most influential demographic and habitat factors to assess current condition, particularly resiliency. The demographic factors we selected included abundance, population growth (in which we considered adult survival rates, juvenile survival rates, and fecundity and growth trend) and genetic diversity. The habitat factors that were identified as the most influential were beetle abundance, beach grass and cover. We identified and ranked (from 1 to 6) the six stressors that most influence the current condition of the species (1 being the worst). These six stressors, from 1 to 6 included: Noise above 60 decibels, decrease in dune beetles, decrease in soothing wave sounds, decrease in beach grass, increase in temperature, and increase in flooding.

CURRENT CONDITION DESCRIPTION

Example graph of population trend from Exercise 5 for each population (Example: The Beach Bums Population)

23

Table 3: Example of Current habitat and demographic data for an example population

Each population was assessed and the data was collected in the table format above. Data varied by population.

24

CAUSE AND EFFECTS – ASSESSING REASONS FOR CURRENT CONDITIONo Individual Effects

By constructing individual logic chains, we were able to isolate stressors that significantly affected individual mice and/or the resources they rely on for breeding, feeding or sheltering needs.

Table 4: Example of analysis of stressor paths that may affect individual and/or the resources that are required to fulfill their lifecycle needs.

o Summary table of stressors/threats from Class Handouts (Island Mouse Threats, Island Mouse Global Climate Change) and information from Interactive Map, ranking threats from worst to least.

After evaluation of the stressors/threats for the species, we used an expert elicitation process to assign an overall ranking value to the six main stressors.

Table 5: Stressor Ranking

Stressor RankIncrease in noise above 60 db.

1

Decrease in Beetles 2Decrease in Soothing Wave Sounds

3

Decrease in Beach Grass 4Increase in Temperatures 5Increase in Flooding 6

Description of stressors/threats:

Noise: Island mice evolved in quiet, serene tropical habitats, so the species is especially sensitive to loud, startling noises. Noise levels that exceed 60 decibels (dB), or the equivalent to a normal office conversation, result in spontaneous cardiac arrest that is always fatal to all Island mice. Natural sources of loud noises on Darlost’s Island include volcanic eruptions and rumblings from Skull Mountain, coconuts that explode upon impact with the ground, and violent thunderstorms.

25

Jack’s sparrow Predation: Jack’s sparrow is a native predator on Darlost’s Island that preys on Island mice and their nests. Jack’s sparrow is a generalist, lives in all three habitat types, and is often associated with humans and commercial development. Jack’s sparrow numbers tend to increase with increased numbers of tourists that litter. Pirate Rat: predator introduced to Darlost’s Island as shipwrecks and other maritime debris wash ashore. Shipwrecks, and as a result the Pirate rats, are currently confined to the Beach Bums southern coast. Further, the Pirate rats’ wooden peg legs sink in sand and other unstable soils, limiting their mobility and restricting their distribution to the coastal beaches. After reaching the Beach Bum coast, the Pirate rats feed opportunistically on Island mice, but quickly die from exposure to cold and intraspecific competition when the northeasterly cold winter trade winds begin to blow from November to May. Shipwrecks harboring Pirate rats float to shore 10 times per year, with approximately 1 Pirate rat per wreck, and only arrive during the summer (May through November) when the cold winter trade winds are not blowing. During the winter, the cold winter trade winds keep the debris, and the Pirate rats, at sea. Disease: Darlost’s Fire, a bacterial skin disease caused by the non-native Claviceps pintoea bacterium currently affects only Island mice in the Message in a Bottle (MIB) population. The disease causes the normally smooth, thick, and shiny pelt of an infected Island mouse to become mottled and patchy, which the native islanders describe as “pinto.” Tourists prize the pinto pelts on keychains, scarves, and other trinkets. Due to the thin and patchy coat, infected Island mice are more susceptible to exposure from cold.Collection: Native islanders from Cannibal Cove harvest Island mice pelts from the Message in a Bottle mouse to craft souvenirs for tourists. Keychains fashioned from the “pinto” pelts of Island mice infected with Darlost’s Fire are extremely popular and are the most popular trinket. The islanders also harvest the thicker and darker fur from the Misty Mountain population for use in ceremonial garments. Toxic gases: Low concentrations of toxic gases from Skull Mountain’s minor eruptions and rumblings decrease reproductive rates for the Island mouse. Higher concentrations of the gases are usually fatal. From May to November, the toxic plume disperses upwards into the atmosphere, but the cold winter trade winds that blow for six months from November to May force the toxic plume to the southwest above Cannibal Cove and the Snowmelt Thicket. Habitat fragmentation and degradation: Commercial and residential development reduces and fragments Island mouse habitats by removing beachgrass, decreasing the availability of dune beetles, increasing predation by Jack’s sparrow, increasing collection for the tourist trade, and by increasing ambient noise levels.

Global Climate change Floods:

Scientists disagree whether global climate change will increase the frequency and magnitude of the spring floods on Darlost’s Island. However, the native people of Cannibal Cove report that they have lost more of their prized summer homes in the Snowmelt Thicket to the floods over the last 5 years.

Thunderstorms:Island-wide thunderstorms, with thunder claps averaging volumes of 120 decibels (dB) near the strike point, currently occur once every year. However, published literature indicates that the frequency of thunderstorms will double over the next 25 years under all climate scenarios. Storms may be windier.

Warming Temperatures:Published literature strongly predicts that annual average temperatures on Darlost’s Island will increase due to global climate change. Under high carbon emission scenarios, the temperature will likely increase by 2 degrees within 50 years, with a 50 percent increase in the number of days that exceed 100°F per year. Under medium and low emission scenarios,

26

the temperature will likely increase by 1 degree and 0.5 degree respectively over the next 50 years, with a 20 percent and 10 percent increase in the number of 100°F days per year. Within the last 5 years, repeat tourists to Darlost’s Island have started complaining that the summers are hotter and longer, which is substantiated by a 50 percent increase in electricity use to power air conditioners at the resort.

Sea Level RiseSea level rise due to global climate change will inundate and reduce coastal habitats, which not only provide habitats for the four Coastal populations of Island mice, but also provide important nesting habitats for the dune beetle, the Island mouse’s primary food source. At the expert elicitation workshop, each climate expert independently agreed that under the high carbon emissions scenario, the sea level will likely rise by 1 foot over the next 50 years. The experts stressed that at this accelerated pace, inundation will exceed the conversion of uplands to beaches, which will cause a 50 percent loss of dune beetle nesting habitat on the beaches. The experts also agreed that under a medium carbon emissions scenario, sea levels will rise by 6 inches in 50 years, but that under a low scenario, the sea level will rise by 2 inches.

Spread of DiseasePetroglyphs in Darlost’s Cave reveal that Claviceps pintoea infections in the Message in a Bottle (MIB) population fluctuated naturally in the past. In his unpublished dissertation, Steven “Marley” James, owner of the Tiki Scuba Shoppe, correlated the fluctuations observed by the cave petroglyphs to historical climate data and found that there were more C. pintoea infections when average annual temperatures were hotter. Specifically, for every 5 percent increase in temperature, Mr. “Marley” found a 10 percent increase in Darlost’s Fire infections in Island mice. An expert panel of epidemiologists indicated that there is a 90 percent chance that Darlost’s Fire will spread to populations other than the MIBs under high emissions scenarios, and a 50 percent and 10 percent chance under medium and low emission scenarios, respectively. However, the experts disagreed on whether warming temperatures would reduce mortality in infected mice from exposure.

27

Population and Species Level Effects (Exercise 7A and B Population-scale Model, and Species-scale Models, pages 16 and 17 of Workbook)

Figure 11: Example of Influence Diagram for Coastal Populations

Figure 12: Example of Conceptual Model of Major Influences of Current Condition at the Species Scale

28

Population Resiliency - Describe methodology for developing the categorical scale for population resilience (H, M, L population resilience) from Exercise 8, page 19` of the Workbook

We developed a qualitative categorical scale for population resiliency in which we identified the conditions under which we would consider a population to have High, Medium or Low resilience (see Table 6). Using the factors of general risk, likelihood of persistence over 50 years, and probability of persistence in Table 6, we defined High, Medium and Low resilience in terms of the demographic and habitat factors needed for population health we identified (See Table 7).

Table 6: Risk Scale of Population Resilience

Overall Condition based on resiliency

Risk Persistence over 50 years Probability of Persistence

High Low Very Likely 90-100%Moderate Moderate Likely 66-90%Low High About as likely as not and

unlikely0-66%

Table 7: Population Resiliency Categories

Population Factors Habitat FactorsResiliency Condition category

Abundance Pop Growth Genetic Diversity

Beetle Abundance

Beach Grass Cover

High 250+ Adult survival >50%,Juvenile survival

No barriers to movementOrRegular or

Not limiting Not limiting Not limiting

29

>=75%,2-3 pups/ female, 2x per year OR positive trend

sporadic immigration

Moderate 100-250 Adult survival 25-50%, Juvenile survival >=75%,Fecundity – 1-3 pups/female, 1-2x/year, OR stable trend

< 1 immigrant per generation

At time limiting

At times limiting

At times limiting

Low < 100 Adult Survival < 25%, Juvenile Survival >=75%, Fecundity 1-2 pups/female 1-2x/year, OR declining trend

Isolated Limiting or Absent

Limiting or Absent

Limiting or Absent

Summary of Overall Current Condition

We applied the risk scale in Table 6 to each demographic and habitat factor for each of the 10 populations, and then assessed the overall condition for each population (see Table 8 below).

30

Table 8: Current Condition of Darlost’s Island Mouse Populations

The Coastal Ecological Setting has moderate redundancy, with four populations in this representative type. Overall habitat conditions are high in quality and quantity. Resiliency is moderate, as Castaways is a sink and does not reproduce. MIB is isolated from the other populations, with limited emigration by Jack sparrow mouse drop. However the Beach Bums population does undertake long distance annual migrations, clearly demonstrating connectivity with inland populations and therefore provides evidence of genetic exchange.

The Paradise Palms setting is represented by four populations distributed across the island. Overall, habitat conditions are moderate to high in quality and quantity. However, population factors are more varied. For example, genetic diversity is high across three populations but low in one (Snowmelt thicket). Abundance and population growth are moderate across populations except at Deadman’s Dunes due to low fecundity and loss of individuals during flooding contributing to an overall decreasing population trend. Information indicates that the current condition of each population is moderate.

Within the Mountain Ecological Setting, there are two known populations of Island Mice: Darlost’s Dome and Misty Mountain. A third population on Skull Mountain was previous extirpated. Both extant populations are small and isolated from each other and all other island populations. There are slightly over 100 individuals on Darlost’s Dome and 50 on Misty Mountain. Although the two populations are isolated from each other, they are affected by the same threats (e.g., effects of small population size, collection, toxic plumes). In addition, because of the isolated nature of the Mountain setting, the extent of available habitat may be a limiting factor to population growth. Because of this isolation, and the fact that there are only two small populations, we consider the Mountain setting to have low redundancy and would therefore not be well able to withstand any catastrophic events. In addition, because of the small size of both extant populations, we believe the Mountain setting has low resiliency overall, with Darlost’s Dome population being slightly more able than Misty Mountain to withstand stochastic disturbances.

31

UNCERTAINTY (DATA GAPS, LINGUISTIC, ETC.)

We are uncertain of the quality and quantity of cover – palms may be limiting at times of flood. We are not certain about genetic diversity – if immigrants arrive, do they even breed?

32

SPECIES’ FUTURE CONDITION AND STATUS INTRODUCTION AND SUMMARY

In this chapter we describe our analysis of the future condition of Z. islandsonius. We developed three scenarios that are plausible for assessing the future condition of the species: an optimistic scenario (stressors decrease), a moderate scenario (status quo), and a pessimistic scenario (stressors increase), using Climate change, Threats, and Conservation actions for each.

METHODSo Discuss how climate change and other stressors were evaluated, and how future scenarios were

developed [identify what climate change scenarios were used, other threats, conservation actions, timeframes selected and why, likelihood, etc.]

We developed three reasonable future scenarios that each included aspects of climate change, threats, conservation actions, and likelihood of the outcome.

Climate change: low: no change in emissions: or high emissions. Threats: decrease in noise over 60 decibels; no change in noise regime;

increase in noise regime Conservation Actions: Various Likelihood: IPCC Guidance

DESCRIBE FUTURE SCENARIOSWe developed three scenarios that we felt reasonably predicted a range of future outcomes for Z. islandsonius for the purpose of this status assessment

Calibrated likelihood scale based on IPCC guidance. See Mastrandea et al. 2011. The IPCC ARS guidance note on

consistent treatment of uncertainties: a common approach across the working groups. Climate change

33

ASSESS FUTURE CONDITION OF EACH POPULATIONo Exercise 9Do Exercise 10, Projecting Future Condition, all populations (Best Case, Moderate and Worst Case

Scenario Tables)o Text from 3 questions, last part of Exercise 11o Map (page 25 of Workbook)

34

Scenario 1 (IPCC Likelihood:______Unlikely_______________________)

Population namePopulation Factors Habitat Factors (overall)

abundance Population growth

Genetic Diversity

beetle abundance

Beach grass Cover Future condition

Beach Bums HIGH MOD HIGH MOD HIGH MOD HIGH

Message in a Bottle HIGH MOD LOW HIGH HIGH HIGH HIGH

Cannibal Cove HIGH HIGH LOW HIGH HIGH HIGH HIGH

Castaways LOW LOW LOW LOW LOW LOW LOW

Snowmelt Thicket MOD MOD LOW HIGH HIGH HIGH MOD

Deadman’s Dunes LOW LOW HIGH HIGH HIGH MOD MOD

Treasure Grove MOD MOD HIGH MOD MOD MOD MOD

Realm of Spirits MOD MOD HIGH MOD MOD MOD MOD

Misty Mountain LOW LOW MOD LOW MOD LOW LOW

Darlost’s Dome LOW MOD LOW MOD MOD HIGH MOD

Skull Mountain X X X X X X extirpated

35

Scenario 2 (IPCC Likelihood:_____About as likely as not________________)

Population namePopulation Factors Habitat Factors (overall)

abundance Population growth

Genetic Diversity

beetle abundance

Beach grass Cover Future condition

Beach Bums HIGH MOD HIGH MOD HIGH MOD HIGH

Message in a Bottle MOD MOD LOW MOD MOD MOD MOD

Cannibal Cove MOD LOW LOW HIGH HIGH HIGH MOD

Castaways LOW LOW LOW LOW LOW LOW LOW

Snowmelt Thicket MOD MOD LOW HIGH HIGH HIGH MOD

Deadman’s Dunes LOW LOW HIGH MOD MOD LOW LOW

Treasure Grove LOW LOW HIGH MOD MOD MOD LOW

Realm of Spirits MOD LOW HIGH MOD MOD MOD MOD

Misty Mountain LOW LOW MOD LOW MOD MOD LOW

Darlost’s Dome LOW MOD LOW MOD MOD HIGH MOD

Skull Mountain X X X X X X extirpated

Scenario 3 (IPCC Likelihood:______Likely____________________________)

Population namePopulation Factors Habitat Factors (overall)

abundance Population growth

Genetic Diversity

beetle abundance

Beach grass Cover Future condition

Beach Bums LOW LOW LOW LOW LOW MOD LOW

Message in a Bottle LOW LOW LOW LOW LOW LOW LOW

Cannibal Cove MOD LOW LOW MOD MOD MOD MOD

Castaways LOW LOW LOW MOD MOD LOW LOW

Snowmelt Thicket LOW LOW LOW MOD MOD HIGH LOW

Deadman’s Dunes LOW LOW MOD LOW LOW LOW LOW

Treasure Grove LOW LOW MOD LOW LOW LOW LOW

Realm of Spirits LOW LOW MOD LOW LOW LOW LOW

Misty Mountain LOW HIGH MOD LOW MOD MOD MOD

Darlost’s Dome LOW LOW LOW LOW MOD HIGH LOW36

Skull Mountain X X X X X X extirpated

Future Condition for each scenario, by Population and Ecological Setting.

Population name Current Condition

Scenario 1 Scenario 2 Scenario 3

IPCC Likelihood:(unlikely)

IPCC Likelihood:(as likely as

not)IPCC Likelihood:

(likely)

Beach Bums HIGH HIGH HIGH LOW

Message in a Bottle HIGH HIGH MOD LOW

Cannibal Cove HIGH HIGH MOD MOD

Castaways LOW LOW LOW LOW

COASTAL ECOLOGICAL SETTING HIGH HIGH MOD LOW

Snowmelt Thicket MOD MOD MOD LOW

Deadman’s Dunes MOD MOD LOW LOW

Treasure Grove MOD MOD LOW LOW

Realm of Spirits MOD MOD MOD LOW

PARADISE PALMS ECOLOGICAL SETTING MOD MOD LOW LOW

Misty Mountain MOD LOW LOW LOW

Darlost’s Dome MOD MOD LOW LOW

Skull Mountain X X X X

MOUNTAIN ECOLOGICAL SETTING MOD MOD LOW LOW

37

CHARACTERIZE SPECIES’ RESILIENCY, REDUNDANCY AND REPRESENTATION

For each Scenario, populations were mapped and tallied by level of resilience (high, moderate, low) for each Ecological Setting.

Table 9 Future Redundancy

Scenario Coastal Paradise Palms MountainsHigh Mod Low High Mod Low High Mod Low

1 3 0 1 0 4 0 0 1 12 1 2 1 0 2 2 0 0 23 0 1 3 0 0 4 0 0 2

Shown below is a mapping of the populations (and their resiliency level) for Scenario 2

GREEN = HIGH ORANGE = MOD RED = LOW

COASTAL PARADISE PALMS MOUNTAIN1. Beach Bums 5. Snowmelt Thicket 9. Misty Mountain2. Message in a Bottle 6. Deadman’s Dunes 10. Darlost’s Dome3. Cannibal Cove 7. Treasure Grove 11. Skull Mountain (extirpated)4. Castaways 8. Realm of Spirits

38

12

3

5

8

4

6

7910

11

Conclusion

We considered each of the three scenarios regarding the potential for the future resiliency of populations and the number and distribution of these populations within and among each of the three representative areas of ecological settings. Under scenario 1 (which is considered unlikely to occur), the Coastal Setting is projected to maintain one highly resilient population, 2 moderately resilient populations, and one low resilient population. The distribution of the high and moderate populations within the Coastal Setting maintains most of the natural distribution across the species’ range within this ecological setting. The Paradise Palms ecological setting is projected in the future to have two moderate and two low resiliency populations. The distribution of the moderately resilient population includes both the north and south sides of the Island. The Misty Mountain setting is projected to have only low resiliency populations in the future, such that the likelihood is low under this scenario for the species to maintain any of the two natural populations within this ecological setting.

Viability is an estimate of the ability of the species to sustain populations over time. In our projections of the future conditions of the species we estimate the expected condition of each population (resiliency), considering the number and distribution (redundancy) of those populations within each of the three ecological settings for the island mouse (representation). Viability is characterized by the overall expected conditions of each population within the ecological settings. We considered the future conditions under three different plausible future scenarios. The scenario considered most likely to occur in the future was scenario 3 which was projected to have 1 moderately resilient and 3 low resilient populations in the Paradise Palms settings; 4 low resilient populations in the Misty Mountains setting; and two low resilient populations in the Mountain setting.

Our analysis suggests that the future effects of climate change, resulting in altered trade wind patterns and increased violent thunderstorms, is the most important future influence on the viability of the Island Mouse. Other local factors are also projected to affect some populations, but the potential effects of climate change are the most significant source of potential major stressors to the species. Because we found that the likelihood of High CO2 emissions climate change models should be considered the most supported climate change projections, we considered Scenario 3 to be a likely scenario (between 66 and 100% probability of occurrence) and the most likely to occur compared to the three scenarios analyzed.

3R Viability Conceptual Model – An Example Only

3R Viability Conceptual Model with Climate Change Stressors – An Example Only

LITERATURE CITED

APPENDICES

1