invasive-species-utac

GenesisAeon Package 117 — real, independently verified invasive- species scale, trophic-cascade, and management science. Last of the five candidate gap-topics from UTACnextSteps.txt (after coral-reef-utac P114, biodiversity-utac P115, pollinator-network-utac P116). Deliberately has no UTAC/CREP/AFET bridge and no invented Γ value — see DISCLAIMER.md.

Deliberately not one-sided

is_invasion_an_inevitable_outcome_of_introduction() and is_eradication_success_rare() both return False — Williamson & Fitter's (1996) "tens rule" shows most species introductions never become invasive, and Spatz et al. (2022)'s real DIISE data shows island invasive-species eradication succeeds 88% of the time (1,550 real attempts, 998 islands). Invasion is not an inevitable, one-way, unmanageable ratchet.

What's real here

• IPBES (2023) Thematic Assessment on Invasive Alien Species — the real, official first global assessment: economic cost exceeded USD 423 billion/year as of 2019, quadrupling every decade since 1970; invasive species have contributed to 60% of recorded global extinctions. Of 37,000+ introduced alien species, just over 3,500 are classified as harmful invasive — a real minority.
• Marshall (2018, Canadian Journal of Fisheries and Aquatic Sciences) — a real, causally-resolved trophic cascade: Nile perch introduced to Lake Victoria in the 1950s drove more than 200 endemic cichlid species to extinction by the 1980s, with a real second-order effect (loss of algae-grazing cichlids contributing to lake eutrophication) beyond the direct predation.
• Williamson & Fitter (1996, Ecology) — the foundational "tens rule": roughly 10% of introductions establish, roughly 10% of those become invasive — most introduced species do not become a problem.
• Spatz et al. (2022, Scientific Reports) — the honesty-check citation: a real synthesis of over 100 years of island invasive- vertebrate eradication attempts, 88% success rate.

Quickstart

pip install invasive-species-utac

from invasive_species_utac import (
    GLOBAL_SCALE, harmful_fraction_of_introduced_species,
    LAKE_VICTORIA_CASCADE, does_the_cascade_stop_at_direct_predation,
    TENS_RULE, rough_fraction_of_introductions_becoming_invasive,
    ERADICATION_RECORD, is_eradication_success_rare,
)

print(GLOBAL_SCALE.annual_cost_usd_billion)       # 423.0
print(round(harmful_fraction_of_introduced_species(), 3))  # ~0.095
print(LAKE_VICTORIA_CASCADE.cichlid_species_lost)  # 200
print(round(rough_fraction_of_introductions_becoming_invasive(), 3))  # 0.01
print(ERADICATION_RECORD.success_rate_pct)         # 88.0
print(is_eradication_success_rare())                # False

Development

pip install -e ".[dev]"
pre-commit install
ruff check src tests
mypy src
pytest

Citation

See CITATION.cff and .zenodo.json.