Partula obesa is a tree snail species known only from the two small islands of Alofi and Futuna (Wallis and Futuna). The invasive predatory species Rosy Wolfsnail (Euglandina rosea) and New Guinea Flatworm (Platydemus manokwari) are present on both islands: the presence of E. rosea in particular is known to impact partulid populations severely, frequently leading to rapid extinction in many locations elsewhere in the Pacific (Cowie 2001). Surveys since 2011 indicate a severe decline in population density on both islands: on Alofi, the population has changed from being locally abundant to only one found in four days of searching, and its survival on Futuna was confirmed in only one locality in 2022. This species is assessed as Critically Endangered due to an inferred reduction in population size of at least 80% over the last decade, and a projected decline of at least 80% expected over the next ten years due to predation from introduced species. Continued biosecurity vigilance is critical to prevent further invasive species establishments in this species' habitat. Continued surveys to determine the current distribution of this species and population size, status and trends are also recommended. Establishment of a captive breeding programme for this species is an urgent priority.

This species is endemic to the two islands (Futuna and Alofi) in Wallis and Futuna.

Until recently, the last record for this species was Kondo's reference to the samples collected by E.G. Burrows on the island of Alofi in 1932 and deposited in the Bishop Museum (lot #115481). There are more recent records from a 2007/8 biotic survey of Wallis and Futuna (Meyer et al. 2008). The malacological component of the 2007/8 Wallis and Futuna survey was led by Ira Richling (Staatliches Museum für Naturkunde Stuttgart). In 2008, she observed a small surviving population of this species on Futuna. On Alofi, it was present in most of the native forest surveyed, although in very variable densities and with evidence of "major population loss along the main foot paths in some areas" (I.Richling. pers. comm.). A return 2011 survey of the southeast (Vaika) of Alofi by Jean-Yves Meyer (Délégation à la Recherche, Ministère de l'Education, de l'Enseignement Supérieur et de la Recherche, Tahiti) found individuals from sea-level up to 280 m elevation on a ridge leading to the summit (Malavai Fagoso). Survival on Futuna was confirmed in one locality in 2022. On both islands the populations were scattered and very low in density, isolated and very scarce, and only a few individuals were seen. The range on Alofi had contracted further by 2023 when surviving snails were found only after four days of searching.

Based on the decline in population density over the last decade, the population is inferred to have undergone a reduction of at least 80% over that time. This rapid decline is still happening and it is likely that a further reduction of at least 80% will occur within the next 10 years.

This arboreal species has been recorded from native tropical lowland rainforest.

The introduced predatory species Rosy Wolfsnail (Euglandina rosea) is present on Futuna and Alofi (ISSG 2011). Its presence is known to impact partulid populations severely, frequently leading to rapid extinction in many locations elsewhere in the Pacific (Cowie 2001). Based on experience on Moorea, French Polynesia (Murray et al. 1988), where the entire partulid fauna was extirpated within less than a decade as a consequence of the introduction of E. rosea, it is reasonable, considering the relatively small population of the species, to project future declines in individuals of this species due to the effects of introduced E. rosea. This is also supported by the abundance of dead shells on Alofi where predator invasion is most recent (I. Richling pers. comm.). Threats also exist from land clearance and deforestation. The New Guinea Flatworm (Platydemus manokwari) has also been present on Futuna since 2015, and this predatory species is now also present on Alofi. This is an additional major threat to the survival of Partula obesa.

Many partulids were used in necklace making but no trade was recorded in this species.

According to Meyer et al. (2008), Wallis and Futuna developed its first nature protection legislation in 2007 and a newly created Service de l'Environnement is tasked with biodiversity conservation and invasive species control.

Field work to define the current distribution of this species, as well as research on its population status and trends, is required. Identification of priority sites for species conservation (e.g. key biodiversity areas that include threatened land snails) and reducing the impacts of human activities, are also urgently needed. Establishment of a captive breeding group is planned.