{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T05:53:36Z","timestamp":1775109216265,"version":"3.50.1"},"reference-count":42,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2020,2,5]],"date-time":"2020-02-05T00:00:00Z","timestamp":1580860800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2020,2,5]],"date-time":"2020-02-05T00:00:00Z","timestamp":1580860800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Sci Rep"],"abstract":"<jats:title>Abstract<\/jats:title><jats:p>The predation of young tortoise is considered a major cause of mortality for many tortoise species. The predation by common ravens has been identified as being responsible for significant decreases in tortoise populations. Mediterranean spur-thighed tortoise hatchlings and juveniles in Maamora forest (Morocco) were studied in order to describe the size\/age class predation of common ravens on young tortoises and infer the drivers of predation risk and population abundance. The results showed a high level of predation on young tortoises (&lt;75\u2009mm carapace length) attributed to ravens in areas with low vegetation cover, representing 100% of the cases of mortality (n\u2009=\u2009147), but it was moderate in covered areas (n\u2009=\u200919), representing 12\u201327%. The population structure of living juveniles differed significantly between covered and uncovered areas, thus suggesting that raven predation might modify juvenile population structure. Finally, N-mixture models showed a positive relationship between (i) bare cover and tortoise detectability that is only evidenced when the plot is far from a perch and (ii) population abundance and shrub species-richness, being higher in uncovered areas. Our results improve the knowledge on predation and survival on this critical stage in life, which is crucial for the conservation of the Mediterranean spur-thighed tortoise.<\/jats:p>","DOI":"10.1038\/s41598-020-58851-5","type":"journal-article","created":{"date-parts":[[2020,2,5]],"date-time":"2020-02-05T11:03:18Z","timestamp":1580900598000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Predation of young tortoises by ravens: the effect of habitat structure on tortoise detectability and abundance"],"prefix":"10.1038","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0319-829X","authenticated-orcid":false,"given":"Amalia","family":"Segura","sequence":"first","affiliation":[]},{"given":"Jos\u00e9","family":"Jimenez","sequence":"additional","affiliation":[]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3509-7696","authenticated-orcid":false,"given":"Pelayo","family":"Acevedo","sequence":"additional","affiliation":[]}],"member":"297","published-online":{"date-parts":[[2020,2,5]]},"reference":[{"key":"58851_CR1","doi-asserted-by":"publisher","first-page":"315","DOI":"10.1670\/0022-1511(2003)037[0315:NAHEOG]2.0.CO;2","volume":"37","author":"DM Epperson","year":"2003","unstructured":"Epperson, D. M. & Colleen, D. H. Nestling and hatchling ecology of Gopher tortoises (Gopherus polyphemus) in southern Mississippi. J. Herpetol. 37, 315\u2013324 (2003).","journal-title":"J. Herpetol."},{"key":"58851_CR2","first-page":"583","volume":"10","author":"SP Campbell","year":"2015","unstructured":"Campbell, S. P., Steidl, R. J. & Zylstra, E. R. Recruitment of desert tortoises (Gopherus agassizii and G. morafkai): a synthesis of reproduction and first-year survival. Herpetol. Conserv. Biol. 10, 583\u2013591 (2015).","journal-title":"Herpetol. Conserv. Biol."},{"key":"58851_CR3","doi-asserted-by":"publisher","first-page":"707","DOI":"10.1034\/j.1600-0587.2001.240609.x","volume":"24","author":"C D\u00edaz-Paniagua","year":"2001","unstructured":"D\u00edaz-Paniagua, C., Keller, C. & Andreu, A. C. Long-term demographic fluctuations of the spur-thighed tortoise, Testudo graeca in SW Spain. Ecography 24, 707\u2013721 (2001).","journal-title":"Ecography"},{"key":"58851_CR4","doi-asserted-by":"publisher","first-page":"2432","DOI":"10.1890\/02-0448","volume":"84","author":"WB Kristan","year":"2003","unstructured":"Kristan, W. B. & Boarman, W. I. Spatial pattern of risk of common raven predation on desert tortoises. Ecology 84, 2432\u20132443 (2003).","journal-title":"Ecology"},{"key":"58851_CR5","first-page":"49","volume":"56","author":"K Ben Kaddour","year":"2006","unstructured":"Ben Kaddour, K., Slimani, T., El Mouden, E. H., Lagarde, F. & Bonnet, X. Population structure, population density and individual catchability of Testudo graeca in the central Jbilets (Morocco). Vie et Milieu 56, 49\u201354 (2006).","journal-title":"Vie et Milieu"},{"key":"58851_CR6","unstructured":"Raymond, K. M. N. Determining habitat preferences of the juvenile Gopher polyphemus using spatially model vegetation on central Florida sandhill. Graduate theses and dissertations (2007)."},{"key":"58851_CR7","first-page":"173","volume":"1","author":"JA Butler","year":"1996","unstructured":"Butler, J. A. & Sowell, S. Survivorship and predation of hatchling and yearling gopher tortoises. Gopherus poliphemus. Chelon. Conserv. Biol. 1, 173\u2013180 (1996).","journal-title":"Gopherus poliphemus. Chelon. Conserv. Biol."},{"key":"58851_CR8","doi-asserted-by":"publisher","first-page":"238","DOI":"10.2307\/1565303","volume":"32","author":"C Keller","year":"1998","unstructured":"Keller, C., D\u00edaz-Paniagua, C. & Andreu, A. C. Survival rates and mortality causes of Testudo graeca hatchlings in southwestern Spain. J. Herpet. 32, 238\u2013243 (1998).","journal-title":"J. Herpet."},{"key":"58851_CR9","doi-asserted-by":"publisher","first-page":"430","DOI":"10.1111\/1365-2664.12774","volume":"54","author":"MG Nafus","year":"2017","unstructured":"Nafus, M. G., Esque, T. C., Averill-Murray, R. C., Nussear, K. E. & Swaisgood, R. R. Habitat drives dispersal and translocated juvenile desert tortoises. J. Applied Ecol. 54, 430\u2013438 (2017).","journal-title":"J. Applied Ecol."},{"key":"58851_CR10","unstructured":"Tom, J. Microhabitats and use of burrows of Bolson tortoise hatchlings in Biology of North American tortoises (ed. Bury, R. B. & Germano, D. J.) 137\u2013146 (National Biological Survey, 1994)."},{"key":"58851_CR11","doi-asserted-by":"publisher","first-page":"352","DOI":"10.1002\/jwmg.449","volume":"77","author":"LL Smith","year":"2013","unstructured":"Smith, L. L., Steen, D. A., Conner, L. M. & Rutledge, J. C. Effects of predator exclusion on nest and hatchling survival in the gopher tortoise. J. Wildl. Manage. 77, 352\u2013358 (2013).","journal-title":"J. Wildl. Manage."},{"key":"58851_CR12","doi-asserted-by":"publisher","first-page":"376","DOI":"10.2307\/1564605","volume":"25","author":"DS Wilson","year":"1991","unstructured":"Wilson, D. S. Estimates for survival gopher tortoises. Gopherus poliphemus. J. Herpetol. 25, 376\u2013379 (1991).","journal-title":"Gopherus poliphemus. J. Herpetol."},{"key":"58851_CR13","doi-asserted-by":"publisher","first-page":"163","DOI":"10.2307\/3672072","volume":"38","author":"RJ Camp","year":"1993","unstructured":"Camp, R. J., Knight, R. L., Knight, H. A. L., Sherman, M. W. & Kawashima, J. Y. Food habits of nesting common ravens in the eastern Mojave Desert. Southwest. Nat. 38, 163\u2013165 (1993).","journal-title":"Southwest. Nat."},{"key":"58851_CR14","doi-asserted-by":"publisher","first-page":"113","DOI":"10.1163\/1568538053693341","volume":"26","author":"F Barje","year":"2005","unstructured":"Barje, F., Slimani, T., El Mouden, E. H., Lagarde, F. & Bonnet, X. Shrewd shrikes and spiny shrubs: a calamity for hatchling Moorish tortoise. Amphibia-Reptilia 26, 113\u2013115 (2005).","journal-title":"Amphibia-Reptilia"},{"key":"58851_CR15","unstructured":"Germano, D. J. Comparative life histories of North American tortoises in Biology of North American tortoises (ed. Bury, R. B. & Germano, D. J.) 175\u2013185 (National Biological Survey, 1994)."},{"key":"58851_CR16","doi-asserted-by":"publisher","first-page":"68","DOI":"10.1643\/0045-8511(2006)006[0068:MPHUAG]2.0.CO;2","volume":"1","author":"A Pike","year":"2006","unstructured":"Pike, A. Movement patterns, habitat use and growth hatchling tortoises. Gopherus polyphemus. Copeia 1, 68\u201376 (2006).","journal-title":"Gopherus polyphemus. Copeia"},{"key":"58851_CR17","first-page":"203","volume":"10","author":"KA Nagy","year":"2015","unstructured":"Nagy, K. A., Hillard, L. S., Tuma, M. W. & Morafka, D. J. Head-started desert tortoises (Gopherus agassizii): movements, survivorship and mortality causes following their release. Herpetol. Conserv. Biol. 10, 203\u2013215 (2015).","journal-title":"Herpetol. Conserv. Biol."},{"key":"58851_CR18","doi-asserted-by":"publisher","first-page":"87","DOI":"10.1655\/HERPMONOGRAPHS-D-13-00002","volume":"27","author":"KH Berry","year":"2013","unstructured":"Berry, K. H., Yee, J. L., Coble, A. A., Perry, W. M. & Shields, T. A. Multiple factors affect a population of Agassiz\u00b4s desert tortoise (Gopherus agassizii) in the northwestern Mojave desert. Herpetolological Monographs 27, 87\u2013109 (2013).","journal-title":"Herpetolological Monographs"},{"key":"58851_CR19","unstructured":"Boarman, W.I. Problems with management of a native predator on a threatened species: raven predation on desert tortoises in Proc.15th Vertebrate Pest Conf. (ed. Borrecco, J.E., & Marsh R.E.). University of California, Davis (1992)."},{"key":"58851_CR20","doi-asserted-by":"publisher","first-page":"1389","DOI":"10.1093\/beheco\/arv096","volume":"26","author":"MG Nafus","year":"2015","unstructured":"Nafus, M. G. et al. Hiding in plain sight: a study on camouflage and habitat selection in slow-moving desert herbivore. Behav. Ecol. 26, 1389\u20131394 (2015).","journal-title":"Behav. Ecol."},{"key":"58851_CR21","first-page":"504","volume":"10","author":"LC Hazard","year":"2015","unstructured":"Hazard, L. C. Post-release dispersal and predation of head-started juvenile desert tortoises (Gopherus agassizii): Effect of release site distance on homing behaviour. Herpetol. Conserv. Biol. 10, 504\u2013515 (2015).","journal-title":"Herpetol. Conserv. Biol."},{"key":"58851_CR22","doi-asserted-by":"publisher","first-page":"285","DOI":"10.1163\/156853812X643710","volume":"33","author":"JD Anad\u00f3n","year":"2012","unstructured":"Anad\u00f3n, J. D. et al. Distribution of Testudo graeca in the western Mediterranean according to climatic factors. Amphibia-Reptilia 33, 285\u2013296 (2012).","journal-title":"Amphibia-Reptilia"},{"key":"58851_CR23","doi-asserted-by":"publisher","first-page":"369","DOI":"10.1163\/15685381-20191143","volume":"40","author":"A Segura","year":"2019","unstructured":"Segura, A. & Acevedo, P. The importance of protected and unprotected areas for the Mediterranean spur-thighed tortoise demography in northwest Morocco. Amphibia-Reptilia 40, 369\u2013371 (2019).","journal-title":"Amphibia-Reptilia"},{"key":"58851_CR24","unstructured":"Birdlife International. Corvus corax (amended version published in 2016) The IUCN Red List of threatened Species 2017: e. T22706068A113271893 (2017)."},{"key":"58851_CR25","first-page":"80","volume":"14","author":"KA Calderon-Chalco","year":"2019","unstructured":"Calderon-Chalco, K. A. & Putman, B. J. The effect of paint marking on predation risk in western fence lizards: a test using clay models. Herpetol. Conserv. Biol. 14, 80\u201390 (2019).","journal-title":"Herpetol. Conserv. Biol."},{"key":"58851_CR26","unstructured":"Berry, K. H., et al. Changes in desert tortoise populations at the desert tortoise research natural area between 1979 and 1985. Desert tortoise council proceedings of the 1986 symposia: 100\u2013123 (1986)."},{"key":"58851_CR27","first-page":"191","volume":"42","author":"KA Nagy","year":"2011","unstructured":"Nagy, K. A., Tuma, M. W. & Hillard, L. S. Shell hardness measurement in juvenile desert tortoises Gopherus agassizii. Herpetol. Review 42, 191\u2013195 (2011).","journal-title":"Herpetol. Review"},{"key":"58851_CR28","doi-asserted-by":"publisher","first-page":"31","DOI":"10.1111\/1365-2664.13269","volume":"56","author":"NA Hansen","year":"2019","unstructured":"Hansen, N. A., Sato, C. F., Michael, D. R., Lindenmayer, D. B. & Driscoll, D. A. Predation risk for reptiles is highest at remnant edges in agricultural landscapes. J. Applied Ecol. 56, 31\u201343 (2019).","journal-title":"J. Applied Ecol."},{"key":"58851_CR29","first-page":"9","volume":"9","author":"J Mart\u00edn","year":"2001","unstructured":"Mart\u00edn, J. When hiding from predators is costly: optimization of refuge use in lizards. Etologia 9, 9\u201313 (2001).","journal-title":"Etologia"},{"key":"58851_CR30","doi-asserted-by":"publisher","first-page":"720","DOI":"10.1046\/j.1365-2664.2001.00642.x","volume":"38","author":"MF Schneider","year":"2001","unstructured":"Schneider, M. F. Habitat loss, fragmentation and predator impact: spatial implications for prey conservation. J. Applied Ecol. 38, 720\u2013735 (2001).","journal-title":"J. Applied Ecol."},{"key":"58851_CR31","doi-asserted-by":"crossref","unstructured":"Dunham, A. E., Morin, P. J. & Wilbur, H. R. Methods for the study of reptile populations in Biology of the reptilia vol 16. Defense and life history (ed. Gans C., & Huey R.B.) 331\u2013385 (Alan Liss, 1988).","DOI":"10.2307\/1445750"},{"key":"58851_CR32","unstructured":"Morafka, D. J. Neonates: missing links in the life histories of North American tortoises in Biology of North American tortoises (ed. Bury, R. B. & Germano, D. J.) 161\u2013173 (National Biological Survey, 1994)."},{"key":"58851_CR33","first-page":"15","volume":"3","author":"F Braza","year":"1981","unstructured":"Braza, F., Delibes, M. & Castroviejo, J. Estudio biom\u00e9trico y biol\u00f3gico de la Tortuga mora (Testudo graeca) en la Reserva Biol\u00f3gica de Do\u00f1ana, Huelva. Do\u00f1ana ActaVertebr. 3, 15\u201341 (1981).","journal-title":"Do\u00f1ana ActaVertebr."},{"key":"58851_CR34","unstructured":"Andreu, A. C. Ecolog\u00eda y din\u00e1mica poblacional de la Tortuga mora, Testudo graeca, en Do\u00f1ana. Tesis doctoral. Univ. Sevilla (1987)."},{"key":"58851_CR35","unstructured":"Aafi, A. Etude de la diversit\u00e9 floristique de l\u00b4\u00e9cosyst\u00e8me de chene-li\u00e8ge du foret de la Maamora. These, Institut. Agron. et V\u00e9t\u00e9r. Hassan II, Rabat (2007)."},{"key":"58851_CR36","doi-asserted-by":"publisher","first-page":"339","DOI":"10.1111\/j.2006.0906-7590.04486.x","volume":"29","author":"JD Anad\u00f3n","year":"2006","unstructured":"Anad\u00f3n, J. D. et al. Factors determining the distribution of the spur thighed tortoise Testudo graeca in south east Spain: a hierarchical approach. Ecography 29, 339\u2013346 (2006).","journal-title":"Ecography"},{"key":"58851_CR37","doi-asserted-by":"publisher","first-page":"205","DOI":"10.1007\/s00267-003-2982-x","volume":"32","author":"WI Boarman","year":"2003","unstructured":"Boarman, W. I. Managing a subsidized predator population: reducing common raven predation on desert tortoises. Environ. Manage. 32, 205\u2013217 (2003).","journal-title":"Environ. Manage."},{"key":"58851_CR38","doi-asserted-by":"publisher","first-page":"108","DOI":"10.1111\/j.0006-341X.2004.00142.x","volume":"60","author":"JA Royle","year":"2004","unstructured":"Royle, J. A. N-mixture models for estimating population size from spatially replicated counts. Biometrics 60, 108\u2013115 (2004).","journal-title":"Biometrics"},{"key":"58851_CR39","doi-asserted-by":"publisher","first-page":"1","DOI":"10.18637\/jss.v043.i10","volume":"43","author":"I Fiske","year":"2011","unstructured":"Fiske, I. & Chandler, R. Unmarked: An R package for fitting hierarchical models of wildlife occurrence and abundance. J. Stat. Softw. 43, 1\u201323 (2011).","journal-title":"J. Stat. Softw."},{"key":"58851_CR40","unstructured":"R Core Team. R: A language and environment for statistical computing. R. Foundation for Statistical Computing, Vienna, Austria, www.R-project.org\/ (2019)."},{"key":"58851_CR41","doi-asserted-by":"publisher","first-page":"1297","DOI":"10.1890\/0012-9658(2000)081[1297:VITLHD]2.0.CO;2","volume":"81","author":"EC Hellgrem","year":"2000","unstructured":"Hellgrem, E. C., Kazmaier, R. T., Ruthven, D. C. & Synatzske, D. R. Variation in tortoise life history: demography of Gopherus berlandieri. Ecology 81, 1297\u20131310 (2000).","journal-title":"Ecology"},{"key":"58851_CR42","unstructured":"Burnham, K. P. & Anderson, D. R. Model Selection and Multimodel Inference: A Practical Information-Theoretic Approach (Springer Verlag, 2002)."}],"container-title":["Scientific Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.nature.com\/articles\/s41598-020-58851-5.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-020-58851-5","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-020-58851-5.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,1,2]],"date-time":"2023-01-02T15:08:22Z","timestamp":1672672102000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.nature.com\/articles\/s41598-020-58851-5"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,2,5]]},"references-count":42,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2020,12]]}},"alternative-id":["58851"],"URL":"https:\/\/doi.org\/10.1038\/s41598-020-58851-5","relation":{},"ISSN":["2045-2322"],"issn-type":[{"value":"2045-2322","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,2,5]]},"assertion":[{"value":"22 October 2019","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"22 January 2020","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"5 February 2020","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"The authors declare no competing interests.","order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"1874"}}