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Leptonycteris yerbabuenae 

Scope:Global
Status_ne_offStatus_dd_offStatus_lc_offStatus_nt_onStatus_vu_offStatus_en_offStatus_cr_offStatus_ew_offStatus_ex_off

Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Chiroptera Phyllostomidae

Scientific Name: Leptonycteris yerbabuenae
Species Authority: Martínez & Villa-R, 1940
Common Name(s):
English Lesser Long-nosed Bat
Taxonomic Notes: Formerly it was treated as a subspecies of L. curasoae (see Simmons 2005). Arita and Humphrey (1988) determined that sanborni is a junior synonym of yerbabuenae and that yerbabuenae is a subspecies of L. curasoae. Koopman (in Wilson and Reeder 1993) used the name L. curasoae for the species occurring in the southwestern United States. Simmons (in Wilson and Reeder 2005) cited references supporting her listing of L. curasoae and L. yerbabuenae as distinct species; the latter species is the one occurring in the United States.
  
Prior to 1962 specimens of what was then known as L. sanborni were reported as L. nivalis.

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2016
Date Assessed: 2015-03-23
Assessor(s): Medellín, R.
Reviewer(s): Solari, S.
Contributor(s): Arroyo-Cabrales, J. and Reid, F.
Justification:
Despite current large population size, this species faces significant threats from disturbance and vandalism at roost sites and from loss of food resources as a result of habitat destruction and degradation. Over the last three generations (18 years) a population decline of almost 10% is estimated (R. Medellin pers. comm.), but it is not sufficient to include the species under a threatened category. However, its area of occupancy is less than 500 km² and the continuing decline of habitat quality stays at values of round 10% over most of its geographic range. These conditions lead the species to being listed in the Near Threatened category, as it is close to qualifying as Endangered based on criterion B2b(iii).
Previously published Red List assessments:
  • 2008 – Vulnerable (VU)

Geographic Range [top]

Range Description:This species is known from southern Arizona and New Mexico (USA) to Honduras and El Salvador (Simmons 2005). It occurs from lowlands to 2,600 m asl but is usually found below 1,800 m asl (Reid 1997).
Countries occurrence:
Native:
El Salvador; Guatemala; Honduras; Mexico; United States
Additional data:
Estimated area of occupancy (AOO) - km2:500
Upper elevation limit (metres):2600
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:It is generally uncommon (Reid 1997). This species is represented by a large number of occurrences or subpopulations. Arita (1991) mapped well over 100 collection sites in Mexico. Arita and Humphrey (1988) reported 269 historical and currently occupied localities in Mexico. Total adult population size is unknown but exceeds 100,000. A single roost in northern Mexico supports probably more than 100,000 individuals. This species is widespread and abundant in Mexico (Arita and Santos-del-Prado 1999). See Cockrum and Petryszyn (1991) for historical and recent population estimates for several sites in Arizona (no decline is evident) and Sonora.

Cockrum and Petryszyn (1991) strongly disputed the reported decline of this species and, in reviewing pertinent data, concluded that little evidence exists to document a long-term decline in Arizona, New Mexico and Sonora. These authors stated "the various recent reports of disappearance appear to be, at least in part, the result of not looking in the right places at the right times" and further reported that "current populations...are little, if any, decreased from those of a quarter century ago. It even has been suggested that populations have increased in the past century because of more suitable roosts being available as a result of mining activity in the area."

Several caves in Mexico did show declines of up to 90% in the 1980s. A program of recovery was established in 1994 where active environmental education and direct conservation action, plus research along several lines were initiated (Medellin and Torres 2013, López 2013). Twenty years later these and other roosts showed stability or growth, which prompted the Mexican federal government to initiate the process of delisting. The United States still considers it Endangered in 2015.
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This species occurs in thorn scrub and deciduous forest. Its range corresponds closely to the distribution of the mezcal plant (Agave angustifolia) in Mexico (Arita 1991). This bat roosts in caves and mines, often in colonies of several thousand. It emerges about an hour after sunset to feed on nectar and pollen of agaves and saguaro cactus in Arizona. It lands on the flowers or may hover for short periods to feed. Plant species visited in central Mexico are similar to those for Leptonycteris nivalis. Some fruit and insects are also taken. Night roosts, including buildings, are used after feeding (Reid 1997). Northern subpopulations migrate south in September and return in May. Young of these migratory subpopulations are born in May to June in large maternity colonies (Barbour and Davis 1969). An additional subpopulation is non-migratory and remains year-round in the tropical dry forest regions of central and western Mexico. In these subpopulations, young are born in December and January.

Number of subpopulations and population size are likely stable or declining at a rate of less than 10% over the last three generations (18 years). In recent years 13 roosts across Mexico had stable or growing populations, including one roost with over 100,000 bats. The habitat in Mexico is primarily tropical deciduous forest and thorn forest (Arita 1991) as well as Sonoran desert. In the United States, this bat roosts in old mines and caves at the base of mountains near alluvial fans vegetated with agave, yucca, saguaro and organ pipe cactus (Barbour and Davis 1969). Young are born in maternity colonies in caves and mines.
Systems:Terrestrial
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):5-6

Use and Trade [top]

Use and Trade: This species is not used.

Threats [top]

Major Threat(s): Previous surveys (USFWS 1988, 1995) stated that the species was threatened by disturbance of roosts, loss of food sources through land clearing and human exploitation, and direct killing by humans. Habitat loss in caves, used for mining and recreation, remains an issue.

Conservation Actions [top]

Conservation Actions: The recommended conservation action is to avoid habitat loss. In Mexico it was listed as threatened under NOM-059-SEMARNAT-2001 but was downlisted to Under Special Protection in 2015 (NOM-059.2015), and deemed to have recovered. It is also listed as a priority for conservation (J. Arroyo-Cabrales pers. comm.). USFWS list the species as Endangered.

Citation: Medellín, R. 2016. Leptonycteris yerbabuenae. The IUCN Red List of Threatened Species 2016: e.T136659A21988965. . Downloaded on 01 July 2016.
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