Acrocephalus luscinius (Guam Reed-warbler)

[Sebbe]

Nightingale Reed-warbler (Acrocephalus luscinius) is being split: list A. nijoi as Critically Endangered (Possibly Extinct), A. hiwae as Critically Endangered, and A. astrolabii, A. yamashinae and A. luscinius as Extinct?

Guam Reed-warbler A. luscinius is also Extinct. The last confirmed sighting of this species was made in 1969, having been said to still be ‘fairly common’ in parts of the Agana Swamp in 1967 or 1968 before rapidly disappearing from this, the species’ last site (Reichel et al. 1992). As with A. yamashinae the species was primarily restricted to wetland habitats, which suffered considerable disturbance (Reichel et al. 1992). On Guam it is likely that the introduced Brown Tree Snake Boiga irregularis delivered the final blow to the species following significant habitat loss from drainage and fires, potential impacts from pesticides and impacts of a variety of additional introduced species (Reichel et al. 1992, Kennerley and Pearson 2010).

www.birdlife.org/globally-threatened-bird-forums/2016/10/nightingale-reed-warbler-acrocephalus-luscinius-is-being-split-list-a-nijoi-as-critically-endangered-possibly-extinct-a-hiwae-as-critically-endangered-and-a-astrolabii-a-yamashinae-and-a/

[Peter]

Acrocephalus luscinius

Taxonomy

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Acrocephalidae

Scientific Name: Acrocephalus luscinius
Species Authority: (Quoy & Gaimard, 1830)
Common Name(s):
English – Guam Reed-warbler, Nightingale Reed-warbler
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
Identification information: 18 cm. Large, lanky, scruffy-looking warbler with long bill and often dishevelled feathers and erect head feathers when singing. Dingy olive-yellow above, with dull yellow eyebrow and underparts. Voice Call a loud distinctive chuck or tchack. Males sing long, loud, varied and complex song. Hints Skulks in dense thickets, more often heard than seen. Male most often sings from exposed perches.

Assessment Information

Red List Category & Criteria: Extinct ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Camp, R., Dutson, G., Freifeld, H., Saunders, A., Radley, P., Mosher, S., Amidon, F. & Gourley, J.
Facilitator/Compiler(s): Benstead, P., Bird, J., Calvert, R., Khwaja, N., Mahood, S., O'Brien, A., Stattersfield, A., Derhé, M., Symes, A., Wright, L, Martin, R
Justification:
This species qualifies as Extinct because of a very rapid rate of decline in its very small global population observed over the past three generations. It is likely that the introduced Brown Tree Snake Boiga irregularis delivered the final blow to the species following significant habitat loss from wetland drainage and increased frequency in fires, potential impacts from pesticides and impacts of a variety of additional introduced species (Reichel et al.1992, Kennerley and Pearson 2010).

Geographic Range
Range Description: This species is historically known from Guam (to USA).
Countries occurrence:
Regionally extinct: Guam
Additional data:
♦ Continuing decline in area of occupancy (AOO): Unknown
♦ Extreme fluctuations in area of occupancy (AOO): Unknown ♦ Estimated extent of occurrence (EOO) - km2:
♦ Continuing decline in extent of occurrence (EOO): Unknown ♦ Extreme fluctuations in extent of occurrence (EOO): Unknown
♦ Continuing decline in number of locations: Unknown
♦ Extreme fluctuations in the number of locations: Unknown
♦ Upper elevation limit (metres): 500

Population

Population: The last confirmed sighting of this species was made in 1969, having been said to still be ‘fairly common’ in parts of the Agana Swamp in 1967 or 1968 before rapidly disappearing from this, the species’ last site (Reichel et al. 1992). As with A. yamashinae the species was primarily restricted to wetland habitats, which suffered considerable disturbance (Reichel et al. 1992). It is likely that the introduced Brown Tree Snake Boiga irregularis delivered the final blow to the species following significant habitat loss from drainage and fires, potential impacts from pesticides and impacts of a variety of additional introduced species (Reichel et al.1992, Kennerley and Pearson 2010).

Trend Justification:
Additional data:
♦ Continuing decline of mature individuals: Unknown
♦ Extreme fluctuations: No ♦ Population severely fragmented: Unknown
♦ Continuing decline in subpopulations: Unknown
♦ Extreme fluctuations in subpopulations: No ♦ All individuals in one subpopulation: No

Habitat and Ecology

Habitat and Ecology: Acrocephalus luscinius was almost exclusively found in freshwater wetland and wetland edge vegetation (Engbring et al. 1982, Reichel et al. 1992, USFWS 1998).
Systems: Terrestrial; Freshwater
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 5.7
Movement patterns: Not a Migrant

Threats

Major Threat(s): Several factors in combination are likely to have caused the species's extirpation, including wetland destruction, predation by the introduced Brown Tree Snake (Boiga irregularis), pesticide-use and major fires.
Conservation Actions [top]

Classifications

Habitats
Threats
Actions In Place
Actions Needed
Research Needed
Uses
1. Forest -> 1.6. Forest - Subtropical/Tropical Moist Lowland
suitability:Suitable season:resident major importance:No
3. Shrubland -> 3.6. Shrubland - Subtropical/Tropical Moist
suitability:Suitable season:resident major importance:No
5. Wetlands (inland) -> 5.4. Wetlands (inland) - Bogs, Marshes, Swamps, Fens, Peatlands
suitability:Suitable season:resident major importance:No
5. Wetlands (inland) -> 5.5. Wetlands (inland) - Permanent Freshwater Lakes (over 8ha)
suitability:Suitable season:resident major importance:No
5. Wetlands (inland) -> 5.7. Wetlands (inland) - Permanent Freshwater Marshes/Pools (under 8ha)
suitability:Suitable season:resident major importance:No

Bibliography

Amidon, F., Camp, R.J., Marshall, A., Pratt, T.K., Williams, L., Radley, P. and Cruz, J.B. 2014. Terrestrial bird population trends on Aguiguan (Goat Island), Mariana Islands. Bird Conservation International 24(4): 505-517.
Camp, R. J. 2008. Trends in bird populations on Saipan.
Camp, R. J., Pratt, T. K., Marshall, A. P., Amidon, F., Williams, L. L. 2009. Recent status and trends of the land bird avifauna on Saipan, Mariana Islands, with emphasis on the endangered Nightingale Reed-warbler (Acrocephalus luscinia). Bird Conservation International 19(4): 323-337.
Camp, R. J., T. K. Pratt, F. Amidon, A. P. Marshall, S. Kremer, and M. Laut. 2009. Status and trends of the land bird avifauna on Tinian and Aguiguan, Mariana Islands. Appendix 3.1. Terrestrial Resource surveys of Tinian and Aguiguan, Mariana Islands, 2008. Working Draft. . U.S. Fish and Wildlife Service, Pacific Islands Fish and Wildlife Office, Honolulu, HI.
Collar, N. J.; Butchart, S. H. M. 2013. Conservation breeding and avian diversity: chances and challenges. International Zoo Yearbook 48(1): 7-28.
Craig, R. J. 1996. Seasonal population surveys and natural history of a Micronesian bird community. Wilson Bulletin 108: 246-267.
Engbring, J., Ramsey, F. L., Wildman, V. J. 1982. Micronesian forest bird survey, 1982: Saipan, Tinian, Agiguan, and Rota. U.S. Fish and Wildlife Service, Honolulu.
Esselstyn, J., J. B. Cruz, L.L. Williams, and N. Hawley. 2003. Wildlife and vegetation surveys: Aguiguan 2002.
IUCN. 2016. The IUCN Red List of Threatened Species. Version 2016-3. Available at: www.iucnredlist.org. (Accessed: 07 December 2016).
Kennerley, P.; Pearson, D. 2010. Reed and bush warblers. Christopher Helm, London.
Marshall, A., Amidon, F. and Radley, P. 2011. Nightingale reed-warbler surveys on Alamagan. Appendix 1. Status of the Micronesian Megapode in the Commonwealth of the Northern Mariana Islands. U.S. Fish and Wildlife Service report to the U.S. Navy. Honolulu, Hawaii.
Marshall, A.P., Amidon, F. P., Radley, P., Martin, G. and Camp, R. 2008. Nightingale reed-warbler on Aguiguan. Appendix 2.4.4. Terrestrial Resource Surveys of Tinian and Aguiguan, Mariana Islands, 2008. Working Draft. , U.S. Fish and Wildlife Service, Pacific Islands Fish and Wildlife Office., Honolulu. HI.
Mosher, S.M. and Fancy, S.G. 2002. Description of nests, eggs, and nestlings of the endangered nightingale reed-warbler on Saipan, Micronesia. Wilson Bulletin 114(1): 1-10.
Mosher, S. M. Submitted. Ecology of the endangered Nightingale Reed-Warbler (Acrocephalus luscinia) on Saipan, Micronesia. MSc Thesis. University of Idaho.
Reichel, J. D.; Wiles, G. J.; Glass, P. O. 1992. Island extinctions: the case of the endangered Nightingale Reed-warbler. Wilson Bulletin 104: 44-54.
Rodda, G.H., and Savidge, J .A. 2007. Biology and impacts of Pacific Island invasive species. 2. Boiga irregularis, the brown tree snake (Reptilia: Colubridae). Pacific Science 61: 307-324.
U. S. Fish and Wildlife Service. 1998. Recovery plan for the Nightingale Reed-warbler Acrocephalus luscinia.


Citation: BirdLife International. 2016. Acrocephalus luscinius. The IUCN Red List of Threatened Species 2016: e.T103780078A94426596. Downloaded on 11 December 2016.
www.iucnredlist.org/details/full/103780078/0

[Sebbe]

Conservation genomics and systematics of a near-extinct island radiation.

Conservation benefits from incorporating genomics to explore the impacts of population declines, inbreeding, loss of genetic variation and hybridization. Here we use the near-extinct Mariana Islands reedwarbler radiation to showcase how ancient DNA approaches can allow insights into the population dynamics of extinct species and threatened populations for which historical museum specimens or material with low DNA yield (e.g., scats, feathers) are the only sources for DNA. Despite their having paraphyletic mtDNA, nuclear SNPs support the distinctiveness of critically endangered Acrocephalus hiwae and the other three species in the radiation that went extinct between the 1960s and 1990s. Two extinct species, A. yamashinae and A. luscinius, were deeply divergent from each other and from a third less differentiated lineage containing A. hiwae and extinct A. nijoi. Both mtDNA and SNPs suggest that the two isolated populations of A. hiwae from Saipan and Alamagan Islands are sufficiently distinct to warrant subspecies recognition and separate conservation management. We detected no significant differences in genetic diversity or inbreeding between Saipan and Alamagan, nor strong signatures of geographic structuring within either island. However, the implications of possible signatures of inbreeding in both Saipan and Alamagan, and long-term population declines in A. hiwae that predate modern anthropogenic threats require further study with denser population sampling. Our study highlights the value conservation genomics studies of island radiations have as windows onto the possible future for the world’s biota as climate change and habitat destruction increasingly fragments their ranges and contributes to rapid declines in population abundances.

onlinelibrary.wiley.com/doi/10.1111/mec.16382

[Sebbe]

Untangling the colonization history of the Australo-Pacific reed warblers, one of the world’s great island radiations.

Island radiations, such as those of the Australo-Pacific, offer unique insight into diversification, extinction, and early speciation processes. Yet, their speciation and colonization histories are often obscured by conflicting genomic signals from incomplete lineage sorting or hybridization. Here, we integrated mitogenomes and genome-wide SNPs to unravel the evolutionary history of one of the world’s most geographically widespread island radiations. The Australo-Pacific reed warblers (Acrocephalus luscinius complex) are a speciose lineage including five species that have become extinct since the 19th century and ten additional species of conservation concern. The radiation spans over 10,000 km across Australo-Papua, Micronesia and Polynesia, including the Mariana, Hawaii and Pitcairn Island archipelagos. Earlier mtDNA studies suggested a stepping-stone colonization process, resulting in archipelago-level secondary sympatry of divergent mtDNA lineages in the Mariana Islands and Marquesas. These studies hypothesised that morphologically similar species on neighbouring islands arose from ecological convergence. Using hDNA from historical museum specimens and modern genetic samples, we show that incomplete lineage sorting and/or gene flow have shaped the radiation of Australo-Pacific reed warblers rather than secondary sympatry. The nuclear genome reconstructs a simpler biogeographic history than mtDNA, showing close relationships between species in the Mariana Islands and Marquesas despite their paraphyletic mtDNA lineages. Gene flow likely involved early and late colonizing waves of the radiation before the loss of ancestral dispersive ability. Our results highlight how collection genomics can elucidate evolutionary history and inform conservation efforts for threatened species.

academic.oup.com/evolut/advance-article/doi/10.1093/evolut/qpae136/7759539?login=false