• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Taxonomic note
Geobiastes squamiger (del Hoyo and Collar 2014) was previously placed in the genus Brachypteracias. Gender agreement of species name follows David and Gosselin (2002b).

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	A3c+4c

Red List history

Year	Category	Criteria
2021	Vulnerable	A3c+4c
2016	Vulnerable	A3c
2012	Vulnerable	A3c
2008	Vulnerable	A3c
2004	Vulnerable
2000	Vulnerable
1996	Vulnerable
1994	Vulnerable
1988	Threatened

Migratory status	not a migrant	Forest dependency	high
Land-mass type	shelf island	Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	135,000 km2	medium
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	1500-7000 mature individuals	poor	inferred	1999
Population trend	decreasing	medium	inferred	2016-2031
Rate of change over the past 10 years/3 generations (longer of the two periods)	20-29%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	30-49%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	30-49%	-	-	-
Generation length	5.1 years	-	-	-

Population justification: The population is inferred to number 2,500-9,999 individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated extent of occurrence is likely to be occupied. This is equivalent to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals. The true population size may lie at the upper end of this estimate, as while the species is described as uncommon it can be easily overlooked and so may be more common than has previously been believed (Collar and Stuart 1985).

Trend justification: This species is inferred to be declining due to ongoing forest loss across its range (Global Forest Watch 2021). Between 2001-2019, this species experienced forest cover loss of 27% (Global Forest Watch 2021). Assuming that the population declines at a similar rate, this equates to a decline of 23% over 3 generations. Hence, the past rate of decline is placed in the band 20-29%. Climate change modelling has also shown this species's ecological niche may decline by c.45% due to climate change over the 50 year period from 2000 to 2050 (Andriamasimanana and Cameron 2013). Between 2016-2019, this species experienced forest cover loss of 11% (Global Forest Watch 2021). Assuming that the population declines at a similar rate, projected forward over 3 generations, this would equate to a loss of 44%. Hence the suspected future rate of decline is placed in the band 30-49%.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Madagascar	extant	native	yes

Country/Territory	IBA Name
Madagascar	Ambatovaky Special Reserve
Madagascar	Andohahela National Park - Section I
Madagascar	Andringitra National Park
Madagascar	Anjanaharibe Classified Forest
Madagascar	Betampona Strict Nature Reserve
Madagascar	Daraina Forest
Madagascar	Mananara-North Biosphere Reserve
Madagascar	Mantadia National Park and Analamazaotra Special Reserve
Madagascar	Marojejy National Park
Madagascar	Masoala National Park
Madagascar	Midongy South National Park
Madagascar	Ranomafana National Park and extension
Madagascar	Sihanaka Forest
Madagascar	South Anjanaharibe Special Reserve and extension
Madagascar	Tsitongambarika NPA
Madagascar	Upper Rantabe Classified Forest
Madagascar	Vondrozo Classified Forest NPA
Madagascar	Zahamena National Park and Strict Reserve

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Lowland	major	resident
Altitude	0 - 1000 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Shifting agriculture	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Hunting & trapping terrestrial animals - Intentional use (species is the target)	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Unknown		Unknown
		Stresses Species mortality
Biological resource use	Logging & wood harvesting - Unintentional effects: (large scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Climate change & severe weather	Habitat shifting & alteration	Timing		Scope		Severity		Impact
		Future		Whole (>90%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Canis familiaris	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Unknown		Unknown
		Stresses Species mortality

Purpose	Scale
Food - human	subsistence, national

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Recommended citation
BirdLife International (2024) Species factsheet: Scaly Ground-roller Geobiastes squamiger. Downloaded from https://datazone.birdlife.org/species/factsheet/scaly-ground-roller-geobiastes-squamiger on 23/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 23/12/2024.