Conservation Biology: Invasive Species, Habitat Loss, and Overexploitation

Comprehensive practice flashcards covering key vocabulary, case studies, hypotheses, and ecological principles from the lecture notes on invasive species, habitat fragmentation, conservation tools, and overexploitation.

Invasive Species

A non-native or alien species whose introduction and movement is the direct result of human interaction, which establishes and negatively impacts the new environment by disrupting ecological tendencies.

Propagule Pressure

A measure of the quantity and frequency of biological propagules (such as seeds, eggs, or individuals) attempting to move from one location to another, where higher pressure increases the probability of successful establishment.

Empty Niche Hypothesis

The hypothesis proposing that invasive species successfully establish because an open or vacant ecological niche exists in the new habitat, often created by disturbances.

Novel Weapons Hypothesis

The hypothesis stating that an introduced species gains a competitive or predatory advantage by possessing weapons, biochemical defenses, or predatory behaviors that naive native species have not evolved to counter.

Enemy Release Hypothesis

The concept that an introduced species escapes the specialized natural predators, parasites, and diseases found in its homeland, enabling rapid and unregulated population growth in its new habitat.

Novel Environment Hypothesis

The concept explaining the success of synanthropic species that share human habitat requirements (such as availability of water, shade, and temperature regulation) and thrive in modified environments.

Lag Phase

The initial stage on an invasion curve during which an introduced species appears harmless and its population grows slowly before transitioning into rapid spread.

Asian Longhorned Beetle

An invasive wood-boring insect with a $1\text{–}2\text{ year}$ life cycle that arrived in North America in solid wood packaging crates, whose delayed discovery in Massachusetts $10\text{ years}$ after Chicago led to eradication failure.

Brandon Road Lock and Dam

A $\$1.5\text{ billion}$ barrier project designed to deter invasive Asian carp from entering the Great Lakes to protect their $\$5.1\text{ billion/year}$ fishery.

Alpha ($\alpha$) Diversity

The species diversity and richness measured within a single localized, easily bounded area, such as a county or a state park.

Beta ($\beta$) Diversity

The turnover or change in species richness between two distinct regions or across time steps, calculated using the formula $\beta = \gamma / \alpha$.

Gamma ($\gamma$) Diversity

The total species richness found across an entire larger regional landscape.

Biotic Homogenization

The flattening of global biodiversity that occurs when unique native communities are displaced and the same cosmopolitan, invasive alien species become dominant everywhere.

Biotic Control (Biocontrol)

The management of an invasive species by deliberately introducing one of its natural enemies, such as introducing moths to feed on invasive Prickly Pear Cacti in Australia.

Lesser Prairie-Chicken (Tympanuchus pallidicinctus)

A grassland bird species exhibiting a behavioral fear of tall structures, whose conservation status has fluctuated politically and whose populations are threatened by habitat degradation and energy development.

Red Hills Salamander (Phaeognathus hubrichti)

A threatened, lungless salamander endemic to a limited distribution in the Red Hills of Alabama, characterized by low fecundity and threatened by habitat loss and Salamander Chytrid Fungus.

Sterile Insect Technique (SIT)

A pest management method where millions of males of a species are reared, sterilized using an X-ray dosage, and released to mate with wild females, driving down population numbers.

Gene Drive

An engineered genetic mechanism that promotes the biased inheritance of specific modified traits (such as sterility or birth defects) through a population at a rate higher than standard Mendelian genetics.

Habitat Conversion

The complete transformation of native wild ecosystems into non-native, human-dominated landscapes, such as damming a river or felling a forest for development.

Habitat Fragmentation

The subdividing of continuous habitat into smaller, isolated habitat patches, which increases edge effects and distance between populations.

Habitat Degradation

The reduction in the overall health, suitability, or quality of an ecosystem without a complete loss of physical habitat, such as an overgrazed pasture.

Green Revolution

An agricultural modernization movement beginning in the 1930s that utilized synthetic fertilizers and pesticides to boost global food production and bring marginal-quality soils into cultivation.

Intercropping

An agricultural practice where multiple crop species are grown together in the same locality to increase biodiversity, reduce erosion, and prevent soil depletion.

Coral Bleaching

A phenomenon where stressed corals turn stone-white after expelling their mutualistic endosymbionts, zooxanthellae dinoflagellates, often triggered by elevated water temperatures.

Florida Torreya (Torreya taxifolia)

The rarest conifer in North America, restricted to Torreya State Park in Florida and targeted for assisted migration northward due to climate change, fungal pathogens, and reproductive failure.

Green Pitcher Plant (Sarracenia oreophila)

An endangered carnivorous flowering plant consisting of 34 known populations with approximately 30 individuals each, threatened by wetland drainage and commercial over-collecting.

SLOSS Debate

An unresolved ecological debate in conservation reserve design questioning whether biodiversity is better conserved through a Single Large reserve or Several Small reserves.

Ecotone

A gradual, softer transition zone between two ecological communities that generally supports higher species diversity than an abrupt, sharp edge.

Matrix

The surrounding landscape in which habitat patches are situated, determining the difficulty and mortality risk for organisms attempting to disperse between fragments.

Neonicotinoids

A class of synthetic insecticides derived from tobacco that target arthropods, indirectly depleting food resources for insectivorous birds such as flycatchers.

Eutrophication

Nutrient pollution in aquatic systems from wastewater or agricultural runoff that causes algal blooms, shading out aquatic plants and depleting dissolved oxygen to create hypoxic or anoxic conditions upon bacterial decay.

Desertification

The progressive degradation of grasslands and shrublands into desert-like systems with reduced vegetative cover, primarily driven by climate change, unsustainable land use, and overgrazing.

Paper Park

A protected area that exists formally on maps and legal documents with established rules, but lacks physical enforcement and local community buy-in, failing to prevent environmental destruction.

Turtle Excluder Device (TED)

A specialized grid fitted into commercial fishing trawl nets that allows captured sea turtles to swim out and escape, drastically reducing drownings.

Rewilding

The conservation practice of restoring degraded ecosystems and trophic cascades by returning key native species or ecological processes, such as reintroducing wolves and beavers to Yellowstone.

Payments for Ecosystem Services (PES)

A market-based conservation instrument, such as Costa Rica's fuel-tax-funded program, that compensates private landowners financially to refrain from harvesting trees, successfully conserving $90\%$ of targeted forests.

Trinational Atlantic Forest Pact

A regional restoration initiative across Argentina, Brazil, and Paraguay that planted over $600{,}000$ native trees, which faced issues of non-uniform restoration because trees were planted primarily where access was easiest.

Overexploitation

The harvesting of a renewable natural resource at a rate exceeding its replenishment rate ($\text{mortality} > \text{recruitment}$), serving as a leading driver of extinction in groups like marine fishes.

Super Predator

A term describing humans as harvest agents who operate at higher rates, broader geographic scales, and kill indiscriminately compared to natural predators.

Overkill Hypothesis

Paul S. Martin's theory proposing that the extinction of large-bodied megafauna in North and South America approximately $20{,}000\text{ years}$ ago was driven by the arrival of human hunters encountering naive prey.

Market Hunting

Commercial harvest driven by external, non-local economic demand that became decoupled from local consumption needs and food spoilage constraints through canning and refrigeration.

IUU Fishing

Illegal, Unreported, and Unregulated commercial or subsistence fishing activities that operate outside management frameworks and obscure total catch losses.

Bushmeat Hunting

The unregulated, commercial or subsistence harvesting of non-traditional wild terrestrial animals for food, creating severe extinction pressures and zoonotic disease risks.

Cut Hunter Hypothesis

The epidemiological theory that zoonotic blood-borne pathogens (such as HIV/AIDS) crossed into humans through direct blood-to-blood contact while butchering wild bushmeat.

Tragedy of the Commons

Garrett Hardin's economic model explaining how individuals with open, unmanaged access to a commonly held resource will act in self-interest to deplete or degrade it beyond its capacity to recover.