Wildlife Study Guide

📖 Core Concepts Wildlife – All undomesticated animals and uncultivated plants that live naturally without human introduction. Habitat – Any ecosystem (desert, forest, urban, etc.) that can support wildlife populations. Defaunation – Loss of animal species from an ecological community. Sixth Mass Extinction – Ongoing, human‑driven loss of biodiversity; 1 million species projected to disappear within decades. Overkill – Harvesting (hunting, fishing) that exceeds a population’s reproductive capacity. Habitat Fragmentation – Breaking continuous habitat into isolated patches, lowering carrying capacity. Introduced (Invasive) Species – Non‑native organisms that establish, reproduce, and outcompete natives. Chains of Extinction – Secondary extinctions that cascade after a primary species is lost. 📌 Must Remember Global wildlife populations ↓ 68 % since 1970 (human activity). 184 countries are CITES members regulating legal wildlife trade. Illegal wildlife trade ≈ drug/weapon trafficking in profit and scale. Wildlife tourism: 3 % of global tourism growth, 7 % of industry revenue, $120 B GDP, 22 M jobs. Primary drivers of destruction: overkill, habitat loss/fragmentation, introduced species, chains of extinction. Bushmeat = non‑traditional game meat; high demand in East Asia threatens sharks, pangolins, primates. 🔄 Key Processes Legal Wildlife Trade Workflow Species assessment → CITES Appendix assignment → Permit application → Export/import verification → Post‑trade monitoring. Overkill Assessment Estimate population size → Calculate sustainable harvest rate (reproductive output) → Compare actual harvest → Flag overkill if harvest > sustainable rate. Invasion Success Check Species introduced → Establishment (reproduction) → Spread → Impact evaluation → Management response. 🔍 Key Comparisons Legal vs Illegal Trade Legal: regulated by CITES, permits required, aims to be sustainable. Illegal: unregulated, profit‑driven, drives species decline, linked to disease emergence. Overkill vs Habitat Destruction Overkill: Direct removal of individuals (hunting, fishing). Habitat Destruction: Reduces space & resources, lowering carrying capacity. Introduced vs Native Species Introduced: May become invasive if they outcompete natives. Native: Part of existing ecological balance. ⚠️ Common Misunderstandings “Wildlife = only wild, remote animals” – Many species (rats, feral cats) thrive in cities. “All wildlife trade is illegal” – Legal trade exists under CITES; illegal trade is a subset. “Defaunation = deforestation” – Defaunation is loss of animals; deforestation is loss of trees (though often linked). “Invasive species always succeed” – Most introductions fail; only a few become problematic. 🧠 Mental Models / Intuition Supply‑Demand‑Pressure Loop: Human demand → increased harvest/trade → population pressure → decline → higher rarity → even higher demand (vicious cycle). Domino Effect Model: Remove a keystone species → dependent species decline → cascade → ecosystem collapse (chains of extinction). 🚩 Exceptions & Edge Cases Some large, slow‑growing fish are vulnerable to overkill even when harvest appears low because of low reproductive rates. Certain introduced species (e.g., ornamental plants) do not become invasive if they cannot reproduce or outcompete natives. Protected areas may still experience illegal poaching if enforcement is weak. 📍 When to Use Which Assessing Threat Level → Use CITES Appendix I for species at imminent risk of extinction; Appendix II for species that could become threatened if trade isn’t controlled. Management Strategy → If decline is due to overkill, implement harvest limits/quotas. If due to habitat loss, prioritize land‑use planning and restoration. Control Action → For invasive species with high reproductive rate, use rapid eradication; for low‑impact introductions, monitor and contain. 👀 Patterns to Recognize High‑value parts (bones, skins, organs) + East Asian demand → red‑flag for illegal trade. Sharp population drop + hunting data → likely overkill scenario. Patchy habitat maps + species with limited dispersal → risk of fragmentation‑driven decline. Sudden disease outbreaks in humans near wildlife markets → possible zoonotic spillover from illegal trade. 🗂️ Exam Traps Confusing “defaunation” with “deforestation.” Remember defaunation = animal loss only. Choosing “habitat loss” as the only cause when the question lists multiple drivers; many problems involve combined overkill + fragmentation. Assuming all urban wildlife are invasive. Some are native species that have simply adapted. Selecting “CITES regulates all wildlife trade.” It regulates legal trade; illegal trade operates outside CITES. Mistaking “chains of extinction” for “food chain.” Chains of extinction refer to secondary species losses, not trophic levels.