Detailed Explanation:

Answer: Option 1 — The International Union for Conservation of Nature

The Invasive Species Specialist Group (ISSG) is a global network of scientific and policy experts on invasive species, organized under the auspices of the Species Survival Commission (SSC) of the International Union for Conservation of Nature (IUCN). The ISSG develops and maintains the Global Invasive Species Database, which is a comprehensive resource on alien and invasive species that threaten biodiversity and ecosystems worldwide.

📝 Short Notes: IUCN and Its Specialist Groups

• IUCN (International Union for Conservation of Nature): Founded in 1948, it is the world's oldest and largest global environmental organization, working on biodiversity conservation and sustainable use of natural resources.
• Species Survival Commission (SSC): The largest of IUCN's six commissions, comprising over 10,000 experts organized into ~160 Specialist Groups focused on various species and conservation issues.
• Invasive Species Specialist Group (ISSG): Established in 1994, it aims to reduce threats to natural ecosystems and native species by increasing awareness of invasive alien species and providing tools for prevention and management.
• Global Invasive Species Database: Maintained by ISSG, it contains information on over 1,000 invasive species, including their ecology, distribution, impacts, and management strategies.
• IUCN Red List: Another major IUCN initiative that assesses the conservation status of species globally, widely recognized as the most comprehensive inventory of biological diversity.