Partulid tree snails endemic to the mariana islands have experienced dramatic geographic range contractions and population declines in recent decades

The U.S. Fish and Wildlife Service awarded $249,544.32 to the Commonwealth of the Northern Mariana Islands Department of Lands and Natural Resources under the State Wildlife Grants Program (CFDA 15.634) to implement targeted conservation management for endemic tree snail species on Rota Island. The two-year project, commencing October 1, 2025, and concluding September 30, 2027, focuses on direct threat reduction and population stabilization for two species of greatest conservation need: Partula lutaensis (Rota tree snail) and Samoana fragilis (fragile tree snail), a federally endangered species. Deliverables include the deployment and evaluation of rat and invasive flatworm (Platydemus manokwari) management strategies across five target snail colonies, the development of a novel landscape-level flatworm control technique, and comprehensive monitoring activities to assess whether predator management successfully reduces invasive species densities and halts partulid population declines.

The project establishes insurance populations for both species pending implementation of comprehensive island-wide and species-wide recovery actions, addressing recent localized extirpations on Rota. By developing and validating new flatworm management methodologies and evaluating integrated predator control strategies, the grantee will generate management outcomes and best practices applicable to tree snail conservation efforts across the Pacific region, contributing to proactive species protection aligned with the State Wildlife Grants Program's objective of preventing species decline before federal endangered species protections become necessary.

Invasive predators such as rats and platydemus manokwari flatworms are a primary threat to mariana partulids long-term survival. On rota island, commonwealth of northern mariana islands (cnmi), partulid colonies have been recently extirpated. The islands partulid species are in need of insurance populations, pending establishment of comprehensive recovery actions. Our project aggressively and systematically provides threat reduction for select partulid colonies on rota through the direct management of invasive predators, as well as the development and evaluation of predator management strategies. We will deploy and evaluate direct RAT and flatworm management, develop a novel flatworm management technique, and determine whether predator control can successfully reduce predator densities and halt partulid population declines. We will conduct management and monitoring activities at four colonies of the rota tree snail (partula lutaensis) and the sole remaining colony of the fragile tree snail (samoana fragilis) on rota. Both p. Lutaensis and s. Fragilis are species of greatest conservation need (sgcn) the latter is federally endangered. Partula lutaensis is endemic to rota island, and samoana fragilis is known only from rota and guam. These target colonies will act as insurance populations, given recent localized extirpations, prior to implementing island-wide or species-wide management actions.while RAT management strategies are well developed, there is no established method for landscape-level p. Manokwari control. By developing a new flatworm management technique, we will improve management outcomes for rota partulids. Our flatworm management technique and predator management evaluations can inform tree snail conservation efforts across pacific