iucn (international union for conservation of nature) red list case studies

IUCN (International Union for Conservation of Nature)

Red List Case Studies

Case Study 1

Taylor’s Salamander Ambystoma taylori (Brandon, Maruska & Rumph, 1981)

Taylor’s Salamander, Ambystoma taylori

TaxonomyBased on both allozymes and mtDNA, this is a very distinctive salamander. The Ambystoma salamanders occurring in other natural lakes around Alchichica are not closely related to this species.

RangeTaylor’s salamander is endemic to Lake Alchichica, a saline crater lake located in eastern Puebla, Mexico, at 2,290 m above sea level. The Ambystoma salamanders occurring in the other natural lakes around Alchichica are not closely related to this species. The surface area of the lake is 2.3 km².

Population

Even at its only known locality this is a rare species, although formerly it was common there. Divers deep in the lake have seen the species recently.

Habitat & Ecology

This salamander usually does not metamorphose, and most individuals live permanently in water. But, occasional individuals have been known to metamorphose. It breeds in the lake, and is usually found in very deep water, often more than 30 m below the surface.



Threats

The most serious threat to the species is water extraction and diversion resulting in the lake becoming even more saline. The water level has dropped many meters over the last two decades. Continued transformation and pollution of the lake is likely to result in the disappearance of this species. Attempts to introduce fish in the lake have failed because of its salinity.

Conservation Measures

Taylor’s salamander does not occur in any protected area. Captive breeding may be an essential short-term measure to save this species, if it is not too late. The protection of the Alchichica lake is an urgent priority. This species is protected under the category Pr (Special protection) by the Government of Mexico.

Is the taxon eligible for Red List assessment?

• Description of the species has been published (Brandon, Maruska & Rumph, 1981).

YES


• The species was formerly common and is now rare• BUT, no indication of the time period over which a

presumed decline has taken place or data to be able to estimate the scale of population decline

NO


Can criterion A be applied?(Population reduction at a specific rate over 10 years or 3 generations (whichever is longer) in the past, present, and/or future)

YES – CR B1ab(iii,v)+2ab(iii,v)

• The total lake area = 2.3 km² therefore the Critically Endangered thresholds for Extent of Occurrence (<100 km²) and Area of Occupancy (<10 km²) are both met CR B1+2

• Main threats are water extraction and pollution, which affect the whole lake and the whole population: only one location CR B1a+2a

• Habitat quality declining (water extraction causing increased salinity), declining population (now rare, ongoing habitat degradation)

CR B1b(iii,v)+2b(iii,v)

Can criterion B be applied?(Restricted geographic range AND severe fragmentation, continuing decline and/or extreme fluctuations)


• Although the population is described as rare, it is difficult to estimate actual numbers of mature individuals from this

NO


Can criterion C be applied?(Small population size and continuing decline)

• Population size cannot be estimated from the information given

• Species is restricted to only one, small location (AOO <10 km², 1 location)

• Continued transformation and pollution of the lake is likely to result in the disappearance of this species VU D2

YES - VU D2

Can criterion D be applied?(Very small or restricted population)


• No quantitative analysis has been carried out

NO

Can criterion E be applied?(Quantitative analysis estimating probability of extinction in the wild)


• Criterion A: • Criterion B:• Criterion C:• Criterion D:• Criterion E:

Final assessment:Taylor’s Salamander (Ambystoma taylori) is

Critically Endangered: CR B1ab(iii,v)+2ab(iii,v)

NOCR B1ab(iii,v)+2ab(iii,v) NOVU D2NO


Case Study 2

Yaoshan TreefrogRhacophorus yinggelingensis

RangeCurrently known only from the Yinggeling Mountain range on Hainan Island, Hainan Province, southern China, at 1,300-1,550m asl (Chou et al., 2007). There are records from Mahuolong and Yinggezui (Chou et al., 2007). Its not been found in surveys of other mountains in Hainan despite surveys there, but it will probably be found in more sites in the Yinggeling Mountain Range (M.W.N. Lau pers. comm.). There are not many areas in Hainan above 1,300m asl (B. Chan pers. comm.).

PopulationIt appears to be a rare species, as during a three-month survey, only three specimens were found (B. Chan pers. comm.). The area of suitable habitat is very small (M.W.N. Lau pers. comm.).

Yaoshan Treefrog, Rhacophorus yinggelingensisChou, Lau & Chan, 2007

Habitat & EcologyKnown only from primary montane rainforest (Chou et al., 2007). It has been found on the leaves of shrubs 30cm over a dried pool in a stream, and in sedges in a dried rain pool on a mountain ridge (Chou et al., 2007). It appears to be a montane species that breeds in still water, and there are not many suitable breeding habitats within its elevational range (M.W.N. Lau pers. comm.). It is not known if it can survive in opened up habitat.

ThreatsThe montane habitat of the species is above the elevation at which human disturbance of the forest is taking place (Chou et al., 2007). The forest was given formal protection in 2004. The species could be at risk if climate change leads to a decrease in rainfall, as the species is believed to be dependent on rainpools for breeding, which are few and far between in the steep terrain where it lives.

Conservation MeasuresOccurs in the Yinggeling Nature Reserve (established in 2004). Surveys are needed to clarify the distribution, ecological requirements and conservation needs of this species.

Yaoshan Treefrog, Rhacophorus yinggelingensis

Criterion A

Criterion B

Criterion C

• It appears to be a rare species• Not many suitable breeding habitats within its elevational range• No specific information indicates a population decline• No generation length given

• EOO and AOO not specified, but “area of suitable habitat is very small”• Main threat = climate change leading to decreased rainfall: 1 location• No continuing declines or extreme fluctuations

• Appears to be a rare species• No specific population size estimates given• No indication of a continuing decline

Maybe NT B1a+2a B1+B2?

B1a+B2a?


VU D2

Criterion A

Criterion B Maybe NT B1a+2a

Criterion C

Criterion D

Criterion E

•No specific population size estimates given•1 location; decrease in rainfall is a plausible future threat

• No quantitative analysis

VU D2VU D2


Case Study 3

Bryophryne zonalis

A. Catenazzi 2009

Range This species is known only from two sites in the upper Marcapata Valley, Provincia de Quipicanchis, in the Cusco Region of Peru. It has been found between 3,129 and 3,285 m asl (Lehr and Catenazzi 2009). A subsequent visit to this area following the species' original discovery relocated the frog at its type locality, but searches of the surrounding area revealed no new records (A. Catenazzi pers. comm. March 2011). It therefore seems likely to be genuinely restricted to the vicinity of the known sites, with an extent of occurrence of around 14.8 km².

PopulationNo population information is available for this species.

Bryophryne zonalis Lehr & Catenazzi, 2009

Habitat & EcologyThis species is apparently confined to fragments of montane cloud and elfin forest along streams, where animals have been found under rock and moss (Lehr and Catenazzi 2009). A single clutch of terrestrial eggs was found in the same area as this presumed direct-developing frog, and may be attributable to it (A. Catenazzi pers. comm. February 2011).

ThreatsNatural habitats in the upper Marcapata Valley have been heavily modified through deforestation, cattle grazing and cultivation, and this frog appears to be confined to remnant forest patches (Lehr and Catenazzi 2009). The surviving forest is difficult to access, and it is unknown whether agricultural development represents a continuing threat; however most evidence of agricultural disturbance is historical (A. Catenazzi pers. comm. February 2011). A road runs through the valley and is due to be paved, but planned rerouting of the main road away from this area may lessen the impact of future construction and improvement work (A. Catenazzi pers. comm. February 2011). The pathogenic chytrid fungus Batrachochytrium dendrobatidis has been detected in one juvenile of this species (Catenazzi et al. in press). The one documented case of infection was a living, apparently healthy specimen (A. Catenazzi pers. comm. February 2011) and it is unknown whether the disease, which has been held responsible for severe declines and disappearances of stream-breeding frogs elsewhere in Peru (Catenazzi et al. in press; Whittaker and Vredenburg 2010), represents a threat to this direct-developing species.

Bryophryne zonalis

Conservation MeasuresThis species is not known from any protected areas, although the inaccessibility of its habitat may afford it some protection from planned road construction (A. Catenazzi pers. comm. February 2011). More research is needed on this species' distribution, population status, life history and threats. This species is known to be susceptible to infection by chytrid fungus, and populations should be monitored to establish whether this disease poses a threat to this frog.

Criterion A

Criterion B

Criterion C

• There is no population information • There is no specific information indicating population declines • No generation length given

• EOO = 14.8 km2

• Known only from two geographical localities, one possible threat-defined location• Historical habitat loss due to deforestation, cattle grazing and cultivation, although there is

no information regarding current human-induced threats • It has tested positive for chytrid fungus, although there are no indications of continuing

decline or extreme fluctuations associated to the fungus

• No specific population size estimates given• No indication of a continuing decline

Bryophryne zonalis

DD

Criterion A

Criterion B

Criterion C

Criterion D

Criterion E

• No specific population size estimates given• 1 location, but no plausible future threat

Bryophryne zonalis


Case Study 4

Patch-nosed SalamanderUrspelerpes brucei

Range This species is currently known from ten small streams (five of them in the same watershed) in the Appalachian foothills (Blue Ridge escarpment in Stephens County and Habersham County) of northern Georgia, and one site across the Tugaloo River in Oconee County, South Carolina, USA (Camp et al. 2009, C. Camp pers. comm. January 2011). All sites can be found within an area of less than 5 km2, and range in elevation from 225-280 m asl (C. Camp pers. comm. January 2011). While the known range is small, it is possible that this species may occur more widely, given that there are many streams in the area that still require survey work (C. Camp pers. comm. January 2011).

Patch-nosed Salamander, Urspelerpes bruceiCamp, Peterman, Milanovich, Lamb, Maerz & Wake, 2009

Habitat & EcologyThis species can be found in small streams associated with steep-walled ravines (C. Camp pers. comm. January 2011), either within or along the banks of the non-flooded part of the streambed (Camp et al. 2009). Individuals were found under rocks and in loose leaf litter; however, it is thought that they might occupy more terrestrial microhabitats under suitably moist conditions. The clutch size appears to vary between 6-14 eggs (Camp et al. 2009), and the species has a multi-year aquatic larval development (C. Camp pers. comm. January 2011).

Patch-nosed Salamander, Urspelerpes brucei

PopulationAdults of this species seem to be relatively rare: the type series comprises eight adults (Camp et al. 2009), and adults have only been found at three of the ten known sites (C.Camp pers. comm. January 2011). But this could also be a function of its suspected fossorial habits. Larvae appeared to be more common at the type locality's study stream (five were collected within 45 min; Camp et al. 2009), and were also found in some of the neighbouring streams (Camp et al. 2009, C. Camp pers. comm. January 2011).

ThreatsNo major obvious threats have been observed at the species' currently known sites; however, further survey work is needed to determine if it occurs more widely and if so, whether damaging activities could be occurring at unknown sites (C. Camp pers. comm. January 2011). Any factor that would disrupt water flow, canopy cover, or leaf-litter layer would likely impact populations (C. Camp pers. comm. January 2011).

Conservation MeasuresAll of the known Georgia sites are located in the Chattahoochee National Forest, while the site in South Carolina is located in the Brasstown Creek Heritage Preserve, which is the highest protection status that the state of South Carolina can give (C. Camp pers. comm. January 2011). However, The species could also occur outside of these protected areas (C. Camp pers. comm. January 2011). More research is needed on this species distribution and population status.


Criterion A

Criterion B

Criterion C

• Adults seem rare, but it could be the species’ biology• There is no specific information indicating population declines • No generation length given

• The area where it is currently known to occur is 5 km2

• There are no continuing declines or extreme fluctuations • There are no evident threats

• Adults seem rare, but it could be the species’ biology• There are no population size estimates (number of mature individuals)• There is no indication of continuing declines


LC

Criterion A

Criterion B

Criterion C

Criterion D

Criterion E

• There are no specific estimates of population size • It occurs in a restricted area, but could it be one location?



Case Study 5

Sarus Crane, Grus antigoneViet Nam National Assessment (2003)

RangeA migrant species that spends the winter months in Viet Nam. Found in 3 disjunct global populations: the Indian subcontinent, Australia & South-east Asia (Cambodia, Viet Nam, Lao PDR, Myanmar; extinct in Thailand & probably China). Occurs in 2 locations in Viet Nam: Tram Chin, where it remains for 3 months/year, and Logo Samat, a stopover point for individuals heading to Cambodia, where it occurs irregularly and stays for 1 week. EOO = 700-900 km². AOO = 400 km².

Grus antigoneSarus Crane

Viet Nam National Assessment (2003)

Population>90% population decline in Tram Chin since 1990 (1990: 128 individuals; 2003: 2 individuals). General population decline in Logo Samat (1992: 7 individuals; 1998: 48 individuals, 2003: 0 individuals). Global population is also in decline.

Habitat & EcologySoutheast Asian populations frequent open and man-made wetlands during the non-breeding season.

Sarus Crane, Grus antigone

ThreatsMain threats are habitat loss and degradation in Tram Chin due to the construction of an irrigation channel, pollution, and fire; habitat loss and degradation in Logo Samat due to encroachment from farmland, human disturbance, and hunting. Populations in neighbouring Thailand and Cambodia are uncertain, but probably stable.

Conservation MeasuresCITES Appendix II. Found in Tram Chin National Park.

Criterion A

Criterion B

Criterion C

• Most individuals found in Tram Chin; irregular in Logo Samat• Past population reduction of >90% in Tram Chin; general decline in Logo Samat

(based on direct observations). No mention of projected future declines• Habitat loss & degradation in both sites; also hunted in Logo Samat

• EOO = 700-900 km² and AOO = 400 km²• 2 locations• Continuing decline in quality and extent of habitat

• 2003: 2 individuals recorded (no precise estimates, but < 250)• Past continuing decline; no mention of future declines• Most individuals in Tram Chin

CR A2acd

EN B1ab(iii)+2ab(iii)

CR C2a(ii)

CR A2a CR A2acd

EN B1+B2

EN B1a+B2aEN B1ab(iii)+B2ab(iii)

CR C CR C

CR C2a(ii)


CR A2acd; C2a(ii)

Criterion A CR A2acd

Criterion B EN B1ab(iii)+2ab(iii)

Criterion C CR C2a(ii)

Criterion D

Criterion E

• < 250 individuals• 2 locations; several existing threats


EN D and VU D2

EN D

VU D2


Case Study 6

Bordon’s Brachypterous Butterfly Redonda bordoni

TaxonomyButterflies of the genus Redonda are endemic to the Andes of Venezuela. This species was not described until 2003.

RangeEndemic to Venezuela and known only from 2 páramos in the Venezuelan Andes, from 3000-3800m. These 2 páramos and the areas between them make up El Batallón and La Negra National Park, which has an area of 952 km². The total area inhabited by the species (based on the combined area of the 2 páramos at the altitudinal range in which the species occurs) is around 180km².

Bordon’s Brachypterous Butterfly, Redonda bordoni

PopulationNo information. Anecdotal observations indicate that the species is relatively abundant in the region, especially males; the number of females is difficult to estimate as they remain hidden in low-lying vegetation.

Habitat & EcologyHas been found in open páramo and humid páramo in intermontane valleys. Males are active and easily found, but the wings of females are considerably reduced and deformed, so they are highly sedentary and make no attempts to fly. Females also have cryptic wings, and are only visible when showing the silvery uppersides. Females scatter their eggs while crawling.


ThreatsBelieved to be very fragile and particularly susceptible to environmental threats. Current threats include habitat loss and degradation due to the loss of host plants, trampling by grazing livestock, agriculture, and fire hazards during the dry season. All of these threaten the larvae, and the females are also particularly vulnerable as they are not very mobile.

ConservationPresent within a national park, though whether the habitat within the park is adequately protected is questionable.


Criterion A

Criterion B

Criterion C

• No known population estimates or trends• Effects of threats on habitat not quantified, and R. bordoni’s precise

response to those threats unknown = cannot indirectly measure population decline (inference, suspicion, projection)

• Total potential range = 952 km²• Known inhabited area = 180 km²• 2 locations• Continuing decline inferred in quality of habitat• No extreme fluctuations


• No known population estimates or trends

EN B1

EN B1a+2a


EN B2



Criterion A

Criterion B EN B1ab(iii)+2ab(iii)

Criterion C

Criterion D

Criterion E

• 2 locations• Plausible threats: habitat loss & degradation, trampling, agriculture, fire


VU D2


iucn (international union for conservation of nature) red list case studies

Documents

lake alchichica

alchichica lake

ambystoma taylori slide

rare species

range taylors salamander

distinctive salamander

total lake area

ambystoma salamanders