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Journal of Ornithology

, Volume 160, Issue 4, pp 1121–1132 | Cite as

The first comprehensive survey of habitat suitability and population size for the endangered Grande Comoro Scops Owl (Otus pauliani): implications for its conservation

  • Mohamed Thani IbouroiEmail author
  • Nassia Ali Hassane
  • Said Moindjié
  • Mouniati Ombade
  • Nassabia Mohamed
  • Mohamed Hamidou Saidou
  • Kassim Abderemane
  • Ali Cheha
  • Jules Chiffard
Original Article

Abstract

The Grande Comoro Scops Owl (Otus pauliani) is an endangered, rare and elusive owl species restricted to the Karthala forest, Grande Comore. This scops owl species is listed among the most threatened animals of the Comoro archipelago. The species is subjected to strong anthropogenic pressures causing a high rate of habitat loss. Little is known about the species’ population size, habitat suitability and geographic distribution, making the establishment of relevant conservation strategies difficult. In this study we assessed the population density and abundance of the species using the distance sampling approach through (1) the conventional distance sampling method (CDS), and (2) density surface modeling (DSM). Based on DSM, we applied a species distribution modeling method to investigate habitat suitability and geographic distribution of the species to close this knowledge gap. Average population density was estimated to be ca. 27 individuals km−2. We estimated a global population size of 3452 individuals. Our DSM suggested that the Grande Comoro Scops Owl has a very limited distribution (133 km2), restricted to high elevations in Grande Comore’s remaining natural forests (between 800 and 2000 m altitude). However, the currently high level of habitat disturbance and conversion of natural forest into agricultural land could render the species vulnerable to extinction. To ensure the viability of the species and the biodiversity of the Karthala forest, we suggest (1) restoring forest and securing corridors in the Karthala remnant forest; (2) avoiding the conversion of secondary forest into agricultural land, and using existing agroforestry for plantation development; (3) involving a broad community of local individuals and entities in their conservation and management.

Keywords

Comoro Islands Density surface modeling Habitat loss Karthala forest Population size Species distribution modeling 

Zusammenfassung

Habitat-Eignung und Populationsgröße: erste umfassende Untersuchung bei der bedrohten Komoren-Zwergohreule ( Otus pauliani ) und Schlussfolgerungen für ihren Schutz.

Die Komoren-Zwergohreule (Otus pauliani) ist eine seltene, bedrohte und schwer aufzuspürende Vogelart, die nur in den Wäldern an den Hängen des Karthala auf den Komoren vorkommt. Sie wird als eine der am meisten bedrohten Tierarten der Komoren-Inselgruppe geführt. Die Art ist einer immensen anthropogenen Belastung ausgesetzt, die mit einem schnellen Verlust an Lebensraum einhergeht. Das Aufsetzen wirksamer Strategien zu ihrem Schutz wird dadurch erschwert, dass nur wenig über die Populationsgrößen, die geographische Verteilung und die Kriterien für geeignete Habitate für diese Art bekannt ist. In unserer Untersuchung bewerteten wir die Populationsdichte und das Vorkommen der Art anhand von Stichprobenverfahren auf Distanz: (1) der konventionellen distance sampling Methode (CDS) und (2) dem density surface modelling (DSM). Auf der Basis der DSM wandten wir ein Spezies-Verbreitungs-Modell (SDM) an, um mit dessen Hilfe die Eignung eines Habitats sowie die geographische Verbreitung der Art zu untersuchen. Die mittlere Populationsdichte schätzten wir auf etwa 27 Individuen pro Quadratmeter, die gesamte Population auf 3452 Tiere. Unser DSM legte nahe, dass die Verbreitung der Komoren-Zwergohreule auf 133 Quadratkilometer außerordentlich klein und auf die Hochlagen (zwischen 800 und 2.000 m Höhe) der Urwälder auf der Komoren-Hauptinsel begrenzt ist. Aber das in letzter Zeit starke Ausmaß an Störungen im Habitat sowie die Konversion von natürlichen Wäldern in landwirtschaftlich genutzte Flächen könnte die Art einer Ausrottung nahebringen. Zum ihrem Erhalt und dem der Biodiversität des Karthala-Forstes schlagen wir folgende Maßnahmen vor: (1) Aufforsten der Wälder und Anlegen sicherer Korridore im Karthala-Forst; (2) keine weitere Umwandlung der Sekundärwälder in landwirtschaftlich genutzte Flächen sowie die Anwendung von Methoden der früheren Agroforstwirtschaft bei der Entwicklung der Plantagen; (3) Einbeziehung möglichst vieler Menschen und Einrichtungen in den Kommunen, wenn Naturschutz-Aktionen durchgeführt werden sollen.

Notes

Acknowledgments

We would like to thank Comoros National Direction of the Environment and Forests for permission to conduct our fieldwork. The fieldwork was funded by the Réseau National d’Aires Protégées (RNAP), Parcs Nationaux des Comores, and the Rufford Foundation (grant no. 26731-2 to M. T. I.) through a research support grant. We are grateful to our local assistants and eco-guards for their contribution and assistance during the field surveys. Special thanks go to Ali Soidik, Ibrahim Msahazi, Fahami Abderemane, our drivers, Abdoulfatah and Abdérémane, and the whole RNAP team. The absence data used in this study were obtained from different Comoros institutions, including the University of Comoros, the Géothermie Project and Comoros National Parks. Finally, we are grateful to the two anonymous reviewers who provided extensive and critical corrections that improved the improvement.

Supplementary material

10336_2019_1689_MOESM1_ESM.docx (19 kb)
Supplementary material 1 (DOCX 18 kb)

References

  1. Akaike H (1973) Information theory and an extension of the maximum likelihood principle. In: The Second International Symposium on Information Theory. Akademiai Kiado, Budapest, pp 267–281Google Scholar
  2. Alba-Zúñiga A, Enríquez PL, Rangel-Salazar JL (2009) Population density and habitat use of the threatened Balsas Screech Owl in the Sierra de Huautla Biosphere Reserve, Mexico. Endanger Species Res 9:61–66.  https://doi.org/10.3354/esr00235 CrossRefGoogle Scholar
  3. BirdLife International (2016a) Otus rutilus. The IUCN Red List of Threatened Species 2016: e.T22735960A95122449. http://dx.doi.org/10.2305/IUCN.UK.2016.  Accessed 5 June 2019
  4. BirdLife International (2016b) Otus collari. The IUCN Red List of Threatened Species 2016: e.T22732046A95041318. http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22732046A95041318.en. Accessed 5 June 2019
  5. BirdLife International (2016c) Otus ireneae. The IUCN Red List of Threatened Species 2016: e.T22688565A93201000. http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22688565A93201000.en. Accessed 5 June 2019
  6. BirdLife International (2017a) Otus pauliani. The IUCN Red List of Threatened Species 2017: e.T22688694A118470970. http://dx.doi.org/10.2305/IUCN.UK.2017. Accessed 5 June 2019
  7. BirdLife International (2017b) Otus moheliensis. The IUCN Red List of Threatened Species 2017: e.T22724585A118472254. http://dx.doi.org/10.2305/IUCN.UK.2017. Accessed 5 June 2019
  8. Bourgoin C, Parker L, Martínez-Valle A, Mwongera C, Läderach P (2017) Une évaluation spatialement explicite de la vulnérabilité du secteur agricole au changement climatique dans l'Union des Comores. Document de Travail no. 205. Wageningen, Les Pays-Bas: CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS). https://ccafs.cgiar.org/fr/publications/une-%C3%A9valuation-spatialement-explicite-de-la-vuln%C3%A9rabilit%C3%A9-du-secteur-agricole-au#.XTLpEegzbIU. Accessed 20 July 2019
  9. Brook BW, Sodhi NS, Bradshaw CJA (2008) Synergies among extinction drivers under global change. Trends Ecol Evol 23:453–460.  https://doi.org/10.1016/j.tree.2008.03.011 CrossRefPubMedGoogle Scholar
  10. Brooks TM, Pimm SL, Collart NJ (1997) Deforestation predicts the number of threatened birds in insular Southeast Asia. Conserv Biol 11:382–394.  https://doi.org/10.1046/j.1523-1739.1997.95493.x CrossRefGoogle Scholar
  11. Brooks TM, Mittermeier RA, Mittermeier CG et al (2002) Habitat loss and extinction in the hotspots of biodiversity. Conserv Biol 16:909–923.  https://doi.org/10.1046/j.1523-1739.2002.00530.x CrossRefGoogle Scholar
  12. Buckland ST, Anderson DR, Burnham K et al (2001) Introduction to distance sampling. Oxford University Press, Oxford, pp 103–108Google Scholar
  13. Buckland ST, Anderson DR, Laake JL et al (2004) Advances in distance sampling. Ecology 89:416.  https://doi.org/10.1890/0012-9658-89.12.3550 CrossRefGoogle Scholar
  14. Daniel BM, Green KE, Doulton H et al (2016) A bat on the brink? A range-wide survey of the critically endangered Livingstone’s Fruit Bat Pteropus livingstonii. Oryx.  https://doi.org/10.1017/s0030605316000521 CrossRefGoogle Scholar
  15. Donlan CJ, Wilcox C (2008) Diversity, invasive species and extinctions in insular ecosystems. J Appl Ecol 45:1321–1329.  https://doi.org/10.1111/j.1365-2664.2007.0 CrossRefGoogle Scholar
  16. Elvidge CD, Sutton PC, Ghosh T et al (2009) A global poverty map derived from satellite data. Comput Geosci 8:1652–1660.  https://doi.org/10.1016/j.cageo.2009.01.009 CrossRefGoogle Scholar
  17. FAO (2010) Évaluation des ressources forestières mondiales 2010. Rapport national: Comores. Report no. FRA2010/044. FAO, RomeGoogle Scholar
  18. Fisher B, Christopher T (2007) Poverty and biodiversity: measuring the overlap of human poverty and the biodiversity hotspots. Ecol Econ 62:93–101.  https://doi.org/10.1016/j.ecolecon.2006.05.020 CrossRefGoogle Scholar
  19. Gaston KJ (1991) How large is a species’ geographic range? Oikos 61:434–438CrossRefGoogle Scholar
  20. Gaston KJ, Blackburn TM, Goldewijk KK (2003) Habitat conversion and global avian biodiversity loss. Proc R Soc B Biol Sci 270:1293–1300.  https://doi.org/10.1098/rspb.2002.2303 CrossRefGoogle Scholar
  21. Goodman SM, Weyeneth N, Ibrahim Y et al (2010) A review of the bat fauna of the Comoro archipelago. Acta Chiropterol 12:117–141.  https://doi.org/10.3161/150811010X504635 CrossRefGoogle Scholar
  22. Granek E (2002) Conservation of Pteropus livingstonii based on roost site habitat characteristics on Anjouan and Moheli, Comoro Islands. Biol Conserv 108:93–100.  https://doi.org/10.1016/S0006-3207(02)00093-9 CrossRefGoogle Scholar
  23. Green KE, Daniel BM, Lloyd SP et al (2015) Out of the darkness: the first comprehensive survey of the Critically Endangered Anjouan Scops Owl Otus capnodes. Bird Conserv Int 25:322–334.  https://doi.org/10.1017/S0959270914000185 CrossRefGoogle Scholar
  24. Hastie T, Tibshirani R (1990) Generalized additive models. Chapman and Hall, New YorkGoogle Scholar
  25. Hawlitschek O, Brückmann B, Berger J et al (2011) Integrating field surveys and remote sensing data to study distribution, habitat use and conservation status of the herpetofauna of the Comoro Islands. ZooKeys 144:21–79.  https://doi.org/10.3897/zookeys.144.1648 CrossRefGoogle Scholar
  26. Hedley SL, Buckland ST, Borchers DL (2004) Spatial distance sampling models. In: Buckland ST, Anderson DR, Burnham KP, Laake JL, Borchers DL et al (eds) Advanced distance sampling. Oxford University Press, OxfordGoogle Scholar
  27. Herremans M, Louette M, Stevens J (1991) Conservation status and vocal and morphological description of the Grand Comoro Scops Owl Otus pauliani, Benson 1960. Bird Conserv Int 1:123–133.  https://doi.org/10.1017/S0959270900002008 CrossRefGoogle Scholar
  28. Hijmans RJ, Etten JV et al (2019) The package raster, https://cran.r-project.org/web/packages/raster/raster.pdf
  29. Ibouroi MT (2017) Conservation de deux mégachiroptères des Comores, une approche multidisciplinaire et intégrative. PhD, Université AgroParisTechGoogle Scholar
  30. Ibouroi MT, Schwitzer C, Rabarivola JC (2013) Population density estimates of two endangered nocturnal and sympatric lemur species from the Mariarano Forest, northern Madagascar, using multiple approaches. Lemur News 17:49–54.  https://doi.org/10.13140/RG.2.1.2320.4961 CrossRefGoogle Scholar
  31. Ibouroi MT, Cheha A, Arnal V et al (2018a) The contrasting genetic patterns of two sympatric flying fox species from the Comoros and the implications for conservation. Conserv Genet 19(6):1425–1437.  https://doi.org/10.1007/s10592-018-1111-6 CrossRefGoogle Scholar
  32. Ibouroi MT, Cheha A, Astruc G et al (2018b) A habitat suitability analysis at multi-spatial scale of two sympatric flying fox species reveals the urgent need for conservation action. Biodivers Conserv 27:2395–2423.  https://doi.org/10.1007/s10531-018-1544-8 CrossRefGoogle Scholar
  33. Kun-Rodrigues C, Salmona J, Besolo A et al (2014) New density estimates of a threatened sifaka species (Propithecus coquereli) in Ankarafantsika National Park. Am J Primatol 76:515–528.  https://doi.org/10.1002/ajp.22243 CrossRefPubMedGoogle Scholar
  34. Lloyd SP (2010) Habitat suitability modelling for the Anjouan Scops Owl, a cryptic and unstudied species. MSc thesis, Imperial College LondonGoogle Scholar
  35. Louette M, Meitre D, Locque R (eds) (2004) La faune terrestre de l’archipel des Comores. Musée Royal de l’Afrique Centrale, TervurenGoogle Scholar
  36. Maugé LA, Ségoufin J, Vernier E, Froget C (1982) Geomorphologie et origine des bancs du nord-est du canal de Mozambique—Ocean Indien occidental (geomorphology and origin of the reef-banks of the north-eastern Mozambique Channel—Western Indian Ocean). Mar Geol 47:37–55CrossRefGoogle Scholar
  37. Meyler SV, Salmona J, Ibouroi MT et al (2012) Density estimates of two endangered nocturnal lemur species from northern Madagascar: new results and a comparison of commonly used methods. Am J Primatol 74:414–422.  https://doi.org/10.1002/ajp.21997 CrossRefPubMedGoogle Scholar
  38. Michon L (2016) The volcanism of the Comoros archipelago integrated at a regional scale. In: Bachèlery P et al (eds) Active volcanoes of the Southwest Indian Ocean. Springer, New York, pp 333–343CrossRefGoogle Scholar
  39. Miller DL, Rexstad E, Burt L, Bravington MV, Hedley SL (2019) The package dsm, https://cran.r-project.org/web/packages/dsm/dsm.pdf
  40. Myers N, Mittermeier RA, Mittermeier CG et al (2000) Biodiversity hotspots for conservation priorities. Nature 403:853–858.  https://doi.org/10.1038/35002501 CrossRefPubMedPubMedCentralGoogle Scholar
  41. Paulay G (1994) Biodiversity on oceanic islands: its origin and extinction. Integr Comp Biol 34:134–144.  https://doi.org/10.1093/icb/34.1.134 CrossRefGoogle Scholar
  42. Pilla P, Puan CL, Lim VC et al (2018) Sunda Scops Owl density estimation via distance sampling and call playback. Sains Malays 47:441–446.  https://doi.org/10.17576/jsm-2018-4703-03 CrossRefGoogle Scholar
  43. R Development Core Team (2016) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna.  https://doi.org/10.1038/sj.hdy.6800737 CrossRefGoogle Scholar
  44. Ripple WJ, Abernethy K, Betts MG et al (2016) Bushmeat hunting and extinction risk to the world’ s mammals. Subject Category: subject areas. Open Sci 3:160498.  https://doi.org/10.1098/rsos.160498 CrossRefGoogle Scholar
  45. Salmona J, Tantely R, Mohamed Thani I et al (2014) Daraina Sportive Lemur (Lepilemur milanoii) density and population size estimates in most of its distribution range: the Loky-Manambato region. Lemur News 18:16–19Google Scholar
  46. Sewall BJ, Granek EF, Moutui MFE, Trewhella WJ, Reason PF, Rodrìguez-Clark KM, Säid I, Caroll JB, Masefield W, Toilibou N, Vély M, Faissoili BM, Feistner TC, Wells S (2007) Conservation action plan for livingstone’s flying fox: a strategy for an endangered species, a diverse forest and the Comorian people, 52 pp. https://sites.temple.edu/bjsewall/files/2016/05/Sewall_et_al_2007_Liv_Cons_Action_Plan_En.pdf. Accessed 20 July 2019
  47. Sewall BJ, Freestone AL, Moutui MFE et al (2011) Reorienting systematic conservation assessment for effective conservation planning. Conserv Biol 25:688–696.  https://doi.org/10.1111/j.1523-1739.2011.01697.x CrossRefPubMedGoogle Scholar
  48. SPANB (2016) Stratégie nationale et plan d’action actualises pour la diversité biologique_v2. https://www.cbd.int/doc/world/km/km-nbsap-v2-fr.pdf. Accessed 20 July 2019
  49. Thomas L, Buckland ST, Rexstad EA, Laake JL, StrindbergS Hedley SL, Bishop JR, Marques TA, Burnham K (2010) Distance software: design and analysis of distance sampling surveys for estimating population size. J Appl Ecol 47:5–14CrossRefGoogle Scholar
  50. Trewhella Will J, Reason WF, Clark KM, Garrnett SR (1998) The curent status of Livingstone’s Flying Fox (Pterpus livinstonii) in the Federal Islamic Republic (RFI) of the Comoros. Phelsuma 6:32–40Google Scholar
  51. Trewhella WJ, Rodriguez-Clark KM, Davies JG et al (2001) Sympatric fruit bat species (Chiroptera: Pteropodidae) in the Comoro Islands (Western Indian Ocean): diurnality, feeding interactions and their conservation implications. Acta Chiropterol 3:135–147Google Scholar
  52. Trewhella W, Rodriguez-Clark KM, Corp N et al (2004) Environmental education programs as conservation tools: lessons from the conservation of critically engangered fruit bats in the western Indian Ocean. Conserv Biol 19:75–85.  https://doi.org/10.1111/j.1523-1739.2005.00548.x CrossRefGoogle Scholar
  53. US Geological Survey (2004) Shuttle radar topography mission. http://srtm.usgs.gov/. Accessed 10 Nov 2015
  54. Virani MZ, Njoroge P, Gordon I (2010) Disconcerting trends in populations of the endangered Sokoke Scops Owl Otus ireneae in the Arabuko-Sokoke forest, Kenya. Ostrich 81:155–158.  https://doi.org/10.2989/00306525.2010.488429 CrossRefGoogle Scholar

Copyright information

© Deutsche Ornithologen-Gesellschaft e.V. 2019

Authors and Affiliations

  • Mohamed Thani Ibouroi
    • 1
    • 2
    • 3
    Email author
  • Nassia Ali Hassane
    • 4
  • Said Moindjié
    • 4
  • Mouniati Ombade
    • 4
  • Nassabia Mohamed
    • 4
  • Mohamed Hamidou Saidou
    • 4
  • Kassim Abderemane
    • 4
  • Ali Cheha
    • 1
  • Jules Chiffard
    • 2
  1. 1.Groupe D’Intervention pour le Développement Durable (GIDD) MoroniHamrambaComoros
  2. 2.EPHE, PSL Research University, CNRS, UM, SupAgro, IRD, INRA, UMR 5175, CEFEMontpellierFrance
  3. 3.UAMI, Université Africain des Métiers d’IgénieurieMoroniComoros
  4. 4.Parcs Nationaux des Comores, Réseau National d’Aires Protégées-RNAPEX-CEFADERMdéComoros

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