Rapid Decrease in Populations of Wild Ring-Tailed Lemurs (Lemur catta) in Madagascar

Abstract

Lemurs are the most threatened group of mammals on earth. Lemur catta (ring-tailed lemur) represents one of the most iconic lemur species and faces numerous anthropogenic threats in the wild. In this study, we present population estimates from 32 sites across the range of L. catta, collected from primary and secondary data sources, to assess the number of ring-tailed lemurs left in the wild. We estimate that there are approximately 2,220 individual L. catta remaining in the 32 sites considered. We note local extinctions of populations of L. catta in at least 12 of the 32 sites examined, and that significantly more extinctions occurred in areas without some form of protection. This decrease in extant populations could represent a decrease of more than 95% of all ring-tailed lemurs in Madagascar since the year 2000. While these results should be considered preliminary, we stress the rapid decline of the species and note that habitat loss, bushmeat hunting and the illegal pet trade are driving populations to local extinction. Based on the data presented here, urgent and immediate funding and conservation action are crucial to ensure the viability of the remaining wild populations of ring-tailed lemurs.

Recent Estimates of Ring-Tailed Lemur (Lemur catta) Population Declines are Methodologically Flawed and Misleading

“…Thus, the figures likely represent severe underestimates of the population sizes at these sites. For example, Tsimanampesotse National Park covers >200,000 ha, yet the population data presented are based on counts at two locations only and are not extrapolated for the whole National Park (LaFleur et al 2017).…”

“…S1). While LaFleur et al (2017) acknowledge their total population estimate as being limited to surveyed sites, Gould and Sauther (2016, p. 94) state that their research Brepresents all known populations,^and misleadingly present their estimate of 2000-2400 individuals as the total wild population of the species globally. Gould and Sauther (2016) also propose a new distribution map for the species, but omit vast areas of unsurveyed suitable habitat without presenting any evidence for their assumption that these areas are devoid of ring-tailed lemurs: of our 45 additional localities, about half (N = 23) lie outside of their suggested distribution areas.…”

“…Recently, LaFleur et al (2017) and Gould and Sauther (2016) attempted to estimate the size of the extant population of ring-tailed lemurs (Lemur catta) based on rapid field assessments and published counts from 32 and 34 sites, respectively, and estimated there to be fewer than 2500 ring-tailed lemurs remaining in the wild (Gould and Sauther 2016: 2000-2400 individuals; LaFleur et al 2017: 2200 individuals). However, both studies have likely severely underestimated the size of the extant ring-tailed lemur population because of a range of methodological problems.…”

“…However, Gardner et al (2009, p. 41) did record the species in both the Fiherenana and Manombo valleys and state: BOur failure to record [this] species elsewhere should therefore not be interpreted as implying their absence in other areas of the PA…^In addition, Gould and Sauther (2016) claim that there are three ring-tailed lemur groups in Nord-Ifotaka based on Semel and Ferguson (2013), although Semel and Ferguson (2013) was focused on characterizing the use of cliffs by lemurs, and not on surveying the ring-tailed lemur population. LaFleur et al (2017) cite Irwin et al (2005) for evidence that ring-tailed lemurs are extirpated from Pic d'Ivohibe and Kalambatritra, yet the latter paper reports a multisite census that 1) did not include Pic d'Ivohibe and 2) did not census the areas of Kalambatritra where ring-tailed lemurs are thought to occur. Finally, LaFleur et al (2017) cite Moniac and Heitmann (2007) to estimate Andohahela's ring-tailed lemur population at 82 individuals; however, this publication is merely an observation of two hunted lemurs within a pit near the National Park, and we were unable to determine the origin of the number 82.…”

“…LaFleur et al (2017) cite Irwin et al (2005) for evidence that ring-tailed lemurs are extirpated from Pic d'Ivohibe and Kalambatritra, yet the latter paper reports a multisite census that 1) did not include Pic d'Ivohibe and 2) did not census the areas of Kalambatritra where ring-tailed lemurs are thought to occur. Finally, LaFleur et al (2017) cite Moniac and Heitmann (2007) to estimate Andohahela's ring-tailed lemur population at 82 individuals; however, this publication is merely an observation of two hunted lemurs within a pit near the National Park, and we were unable to determine the origin of the number 82.…”