chapter 13 conservation bio

What is the "medical approach" to population management

Diagnose first, intervene second, monitor continuously. Manage populations as deliberately as a physician treats a patient — identify the specific bottleneck, choose the least intrusive intervention that addresses it, and track outcomes with monitoring to adjust if needed.

Name three conditions that justify direct population management

1) A population is already small, isolated, or declining fast; 2) A single limiting factor can be identified and changed; 3) Waiting for full ecosystem recovery would take too long.

What is a "bottleneck" in population conservation

A limiting factor that restricts population growth. Can be a resource (food, water, shelter), a threat (predation, disease, toxins), a demographic problem (too few breeders, poor sex ratio), or a movement barrier (no dispersal route to safe habitat).

Why is managing for a single resource (like food) often insufficient

Because habitat is a complete resource PACKAGE including energy, water, nutrients, space, and suitable physical conditions. A habitat can look suitable but lack one critical resource that limits growth.

What are the three main population management levers

1) Providing resources (food, water, nesting sites, shelter, host plants); 2) Controlling threats (predators, disease, toxins, disturbance); 3) Direct manipulation (translocation, reintroduction, reinforcement, captive breeding).

When is supplemental feeding most justified

When natural food source is scarce, contaminated, or unreliable, AND poor nutrition or toxic prey is clearly suppressing recruitment. Must be used as a SHORT-TERM BRIDGE with clear exit strategy to avoid creating dependency.

Name three major risks of supplemental feeding

1) Dependence on feeding stations after aid stops; 2) Crowding spreads disease and alters behavior; 3) Wildlife associates humans with food, increasing human-wildlife conflict.

What California condor management example combines resource provision AND threat control

Providing lead-free carcasses (resource) addresses the underlying threat (lead contamination in natural prey). This is threat control (eliminating toxins at source) rather than just resource provision.

Why do Karner blue butterflies need disturbance management

Without disturbance (prescribed fire, mowing), woody vegetation shades out wild lupine and nectar plants that butterflies depend on. Disturbance is therefore a RESOURCE MANAGEMENT tool for this species.

Under what conditions are water additions in dry landscapes most defensible

When drought is an identified bottleneck AND disease, crowding, and vegetation damage are monitored simultaneously. Water can concentrate animals, predators, and pathogens, so these secondary effects must be tracked.

What limiting factor do artificial nest sites address for Eastern Hellbenders

Safe breeding habitat. Hellbenders require rocky substrates and concealment; nest boxes substitute when natural cavities are limiting. Must be designed to reduce predator access.

Name two ways shelter/cover indirectly improves survival

1) Reduces exposure to predators; 2) Reduces exposure to extreme weather. Also allows thermoregulation and rest.

What is "plant-centered management"

Management that focuses on providing or maintaining specific host plant species used by larvae, pollinators, or browsers. Goal is not more biomass in general, but the RIGHT PLANT in the RIGHT CONDITION (e.g., milkweed for monarchs).

What is the "Providing Resources" management rule

Supply the missing resource, but only after identifying which resource is truly missing. Must diagnose → target → protect added resources from attracting new threats → monitor for dependence.

Why is threat control often more effective than resource provision

Because removing the stressor usually scales better than hand-feeding individuals, restores more natural behavior and demographic rates, and addresses root cause rather than just compensating for the problem.

How do exclosures work to protect populations

Physical barriers (fences, cages, electric exclosures) protect vulnerable life stages from predators at the place of greatest risk. Can be installed quickly around nests, colonies, or translocation sites.

What are the main limitations of exclosures

1) High cost and maintenance burden; 2) Don't scale well; 3) Can trap chicks or attract new predators if poorly designed.

Is rhino dehorning a permanent solution to poaching

No. While removing horns can lower poaching value for some populations, it does NOT eliminate demand, surveillance needs, or governance failures. It is a THREAT-REDUCTION TOOL, not a substitute for broader protection.

Why is protecting prairie dog populations as important as vaccinating black-footed ferrets

Because ferrets depend entirely on prairie dogs for food. Plague threatens both species. If prairie dogs are eliminated by plague, ferret vaccination is useless. Protecting the prey base matters as much as treating the focal species.

Name the three components of integrated disease control for conservation

1) Vaccination or medical treatment of focal species; 2) Disease management in prey/ecological supports; 3) Habitat/ecological protection of supporting species. Cannot treat focal species in isolation.

What is the California condor example teaching about toxin management

When prey/carrion is contaminated, reduce contamination at the SOURCE rather than perpetually supplementing. Non-lead ammunition policies and hunter outreach address the driver directly — this is threat control, not just resource provision.

Distinguish between disturbance as a THREAT versus disturbance as a TOOL

THREAT: Kills immobile life stages, destroys nests at wrong time, opens site to invasives or erosion. TOOL: Maintains open habitat for disturbance-dependent species, reduces woody encroachment, stimulates germination. Context and timing determine whether it helps or harms.

What is the "Controlling Threats" management rule

Remove the pressure whenever possible; compensate for it only when pressure removal is too slow or infeasible. Tailor approach to threat type (predators, disease, toxins, disturbance).

Define the four types of direct manipulation

1) REINFORCEMENT: Add individuals to small existing population; 2) REINTRODUCTION: Return species to former range; 3) TRANSLOCATION: Move animals to new suitable sites; 4) ASSISTED MIGRATION: Establish outside historical range under severe change (e.g., climate).

What are three critical PRE-RELEASE decisions for successful translocation

1) Site selection: Adequate resources AND threats controlled (predators, disease); 2) Individual screening: Healthy, wild-type behavior, good age/sex structure; 3) Ecological preparation: Decide if predators/competitors must be removed first.

What are three critical POST-RELEASE monitoring metrics for translocated populations

1) Survival, breeding success, and recruitment; 2) Whether population persists WITHOUT continual support; 3) Genetic diversity and disease status (matter as much as headcounts).

What is the difference between counting releases and establishing a successful translocation

Counting released animals is not the same as establishing a SELF-SUSTAINING population. Success requires monitoring that the population reproduces and persists independently, not just that releases occurred.

What is a "soft-release" technique and why is it important for social species

Allowing released animals time to form social bonds, acclimate, and learn the release area before full freedom. Important because social species need stable group behavior, not just food and shelter, for survival.

What can captive breeding do for conservation

1) Prevent immediate extinction when wild population collapses; 2) Increase numbers for reinforcement/reintroduction; 3) Allow veterinary care and controlled pairing; 4) Preserve lineage temporarily.

Why are managers cautious about captive breeding

1) Domestication selection and loss of wild behavior appear quickly; 2) Facilities expensive and can hold only fraction of needed genetic diversity; 3) Release success depends on habitat and threat control OUTSIDE captivity; 4) Cannot substitute for functioning wild system.

What is the risk of "outbreeding" and how is it avoided

Negative genetic effects from mating between distant populations. Avoided by choosing SOURCE POPULATIONS carefully — typically selecting animals from nearby populations adapted to similar conditions rather than distant sources.

What was the critical bottleneck in the black robin crisis in 1976

Multiple simultaneous bottlenecks: only 7 birds, no natural nesting sites, predation, parasites, and inadequate food. By 1979, only 5 remained.

Name the five main tools used in black robin recovery

1) Egg fostering (direct manipulation); 2) Supplementary feeding (resources); 3) Nest boxes (resources); 4) Predator control (threats); 5) Parasite management (threats).

Why did black robin recovery succeed while similar efforts fail for other species

Managers identified MULTIPLE bottlenecks and addressed them SIMULTANEOUSLY with stacked, adaptive interventions. Also, habitat recovery reduced the need for perpetual emergency care. This level of effort cannot be repeated for every species.

What key principle does the black robin recovery illustrate about population bottlenecks

Populations can be limited by MORE THAN ONE FACTOR at the same time. Single-tool approaches fail. Strongest programs stack multiple interventions targeting different bottlenecks simultaneously.

What does the black robin recovery teach about population management as a temporary strategy

Population management should be treated as a TEMPORARY BRIDGE to a more resilient ecosystem state. Habitat recovery allowed the population to eventually persist with less intensive emergency management.

What do Mauritius bird recoveries (kestrel and parakeet) demonstrate

Island species often face MULTIPLE INTERACTING BOTTLENECKS requiring simultaneous management of habitat, predators, and demography. Single interventions are insufficient; multi-pronged approaches work best.

Why is the black-footed ferret-prairie dog relationship a key lesson about ecosystem thinking

Cannot save the ferret without protecting the prairie dog prey base. Plague vaccination alone fails if plague eliminates prairie dogs. Long-term persistence requires LANDSCAPE-SCALE prairie dog conservation — ecological relationships are inseparable from population management.

What did scarlet macaw releases teach about behavioral preparation

Soft-release techniques allowing time for social bonding and site learning improve survival. Social species need stable group behavior, not just food and shelter. Behavioral preparation is therefore part of population management.

Why was tuatara translocation success dependent on island restoration

Translocation works best after invasive mammals are removed and release sites are secured. Predator-free islands and fenced sanctuaries must be created FIRST. Restoration and movement are inseparable parts of the strategy.

When is population reduction (rather than augmentation) a conservation goal

When invasive species eliminate native prey/plants, when overabundant herbivores simplify habitat and suppress regeneration, or when human-wildlife conflict rises from accumulated predators/food subsidies near people.

What was Project Isabela and why was it successful

1997-2006 eradication of over 150,000 feral goats from Galápagos Islands (Pinta, Santiago, Northern Isabela). Successful because removing one invasive predator released many native species from chronic suppression, saving vegetation and tortoise populations.

What are the advantages of fertility control over culling for invasive species

1) Often more socially acceptable; 2) Useful where repeated lethal control is restricted; 3) Can target long-lived species where growth depends on adult survival.

What are the limitations of fertility control

1) Often expensive and laborious to deliver at scale; 2) Population decline may be slow if survival remains high; 3) Does little if immigration from nearby sites replaces treated animals.

What is the four-step evidence-based management framework

1) HYPOTHESIS: What limiting factor are we changing 2) ACTION: What tool will change it 3) MONITORING: Did survival, breeding, or impact change 4) REVISION: Continue, revise, or stop Name five questions on the pre-intervention checklist before proposing population management. 1) Have we identified the most likely limiting factor 2) Is habitat adequate or can it be made adequate first 3) Will action reduce dependence over time rather than increase it4) Are disease, genetics, and behavior considered 5) Do we have monitoring tied to survival/reproduction, not just attendance

What does "adaptive management" mean in population conservation context

Using monitoring data to continuously adjust or revise interventions. If monitoring shows the intervention is working, continue. If not working or causing harm, change or stop the intervention. Management is treated as an experiment.

What is "critical habitat"

The complete resource package an organism needs: energy (food), water, nutrients, living space, and suitable physical conditions. Not just one resource, but the entire integrated set.

What does "self-sustaining population" mean

A population that persists and reproduces without continual human intervention or support. The real goal of translocation/reintroduction — not just releasing animals, but establishing independent populations.

What is the difference between "source population" and "recipient population" in translocation

SOURCE: The population from which individuals are taken (often must be large/healthy enough to sustain losses). RECIPIENT: The population or site receiving individuals (must have adequate habitat and threat control, or must be an entirely new site).

Define "domestication selection

Rapid evolution of behavioral and physical traits in captive animals selected (often unintentionally) for docility and captive reproduction. Can appear quickly in just a few generations, reducing "wildness" needed for survival after release.

What is an "exclosure"

A physical barrier (fence, cage, electric fence) that protects vulnerable life stages or entire breeding sites from predators. Creates predator-free space for nesting, though expensive to maintain. What does "threat reduction" mean

What is "assisted migration"

Establishing a species outside its historical range under severe environmental change (e.g., moving species to higher elevation or latitude as climate changes). Controversial because it's moving species beyond their native range.

What is "genetic diversity" and why does it matter in translocation

Variation in genes within a population. Important because inbred populations have reduced fitness and adaptive capacity. Monitoring programs track genetic diversity alongside population numbers.

According to the chapter, what combination of approaches is most likely to succeed

Programs that combine multiple management levers (resources, threats, direct manipulation) rather than relying on just one. Strongest programs stack interventions targeting different bottlenecks simultaneously.

How does habitat restoration relate to population management

Most interventions work best when PAIRED with habitat restoration. Population management is a temporary bridge; long-term success depends on securing suitable habitat. They are complementary, not competing approaches.

Is the relationship between population size and management intensity

Smaller, more isolated populations require MORE intensive management. Very small populations (like black robin's 7 birds) need all three management levers simultaneously. Larger, healthier populations may need only threat control or minor resource additions.

Why does the chapter emphasize "diagnosis first"

Because the entire intervention strategy depends on correctly identifying the actual limiting factor. If diagnosis is wrong (e.g., thinking food shortage when real problem is predation), the intervention will fail. Diagnosis must be based on field data and natural history knowledge.

What is the "least intrusive intervention" principle

Once bottleneck is identified, choose the SIMPLEST tool that addresses it, rather than jumping to intensive or risky interventions. Example: Add nest boxes (simple) before captive breeding (intensive) if nesting sites are limiting.

Why can't population management succeed without considering the entire ecosystem

Because species don't exist in isolation. Focal species depend on prey, plants, environmental conditions, and absence of threats. If ecosystem support is lacking, fixing just the focal species fails (e.g., ferret-prairie dog example).

What is the fundamental trade-off of direct population management

It is labor-intensive, expensive, and often creates dependence. Badly designed actions can cause unintended harm. Therefore, use it only when conditions clearly justify it: small/isolated/declining populations with single identifiable bottleneck where waiting for ecosystem recovery would take too long.

How should managers think about their role in ongoing conservation

As physicians, not as permanent caretakers. Diagnose the problem, intervene with appropriate treatment, monitor recovery, and work toward patient independence. The goal is to reduce human intervention over time, not create permanent management dependence.

What is the primary reason the chapter uses the black robin as its main example

Because it illustrates both SUCCESS and LIMITATIONS: a species can be rescued from brink of extinction through intensive work, BUT this level of effort cannot be repeated for every species, AND long-term success required habitat support alongside population management.

Name three characteristics of a strong conservation program based on chapter examples

1) Multiple complementary interventions addressing different bottlenecks simultaneously; 2) Habitat restoration paired with population management; 3) Monitoring tied to survival/reproduction with adaptive willingness to revise approaches.

What are the three main reasons to use direct population management

1) POPULATION STATUS: Small, isolated, or rapidly declining; 2) BOTTLENECK: Single limiting factor identifiable and changeable; 3) TIME: Full ecosystem recovery would take too long.

What are the four types of bottlenecks and one example tool for each

RESOURCES (nest boxes) → THREATS (predator control) → DEMOGRAPHY (captive breeding) → MOVEMENT (translocation to new sites)

What monitoring questions determine translocation success

1) Do individuals survive 2) Do they reproduce 3) Are young recruited 4) Can population persist WITHOUT support 5) Is genetic diversity maintained

What is the biggest risk of each management approach

RESOURCES: Dependence on human provision | THREATS: May raise ethical/social conflicts | DIRECT MANIPULATION: Logistically risky, expensive, high failure rate