Dynamic occupancy modelling to determine the status of a Critically Endangered lizard
Monitoring of cryptic or threatened species poses challenges for population assessment and conservation, as imperfect detection gives rise to misleading inferences about population status. We used a dynamic occupancy model that explicitly accounted for occupancy, colonization, local extinction and d...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2023-01-01
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| Series: | Oryx |
| Subjects: | |
| Online Access: | https://www.cambridge.org/core/product/identifier/S0030605321000843/type/journal_article |
| _version_ | 1797754611851853824 |
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| author | Heléna Turner Richard A. Griffiths Mark E. Outerbridge Gerardo Garcia |
| author_facet | Heléna Turner Richard A. Griffiths Mark E. Outerbridge Gerardo Garcia |
| author_sort | Heléna Turner |
| collection | DOAJ |
| description | Monitoring of cryptic or threatened species poses challenges for population assessment and conservation, as imperfect detection gives rise to misleading inferences about population status. We used a dynamic occupancy model that explicitly accounted for occupancy, colonization, local extinction and detectability to assess the status of the endemic Critically Endangered Bermuda skink Plestiodon longirostris. During 2015–2017, skinks were detected at 13 of 40 surveyed sites in Bermuda, two of which were new records. Ten observation-level and site-specific covariates were used to explore drivers of occupancy, colonization, extinction and detectability. Sites occupied by skinks tended to be islands with rocky coastal habitat and prickly pear cacti; the same variables were also associated with reduced risk of local extinction. The presence of seabirds appeared to encourage colonization, whereas the presence of cats had the opposite effect. The probability of detection was p = 0.45, and on average, five surveys were needed to reliably detect the presence of skinks with 95% certainty. However, skinks were unlikely to be detected on sites with cat and rat predators. Dynamic occupancy models can be used to elucidate drivers of occupancy dynamics, which in turn can inform species conservation management. The survey effort needed to determine population changes over time can be derived from estimates of detectability. |
| first_indexed | 2024-03-12T17:34:57Z |
| format | Article |
| id | doaj.art-c4d8723db2684d4db11dabe35a3b2080 |
| institution | Directory Open Access Journal |
| issn | 0030-6053 1365-3008 |
| language | English |
| last_indexed | 2024-03-12T17:34:57Z |
| publishDate | 2023-01-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Oryx |
| spelling | doaj.art-c4d8723db2684d4db11dabe35a3b20802023-08-04T12:01:30ZengCambridge University PressOryx0030-60531365-30082023-01-0157232910.1017/S0030605321000843Dynamic occupancy modelling to determine the status of a Critically Endangered lizardHeléna Turner0https://orcid.org/0000-0002-6067-888XRichard A. Griffiths1https://orcid.org/0000-0002-5533-1013Mark E. Outerbridge2https://orcid.org/0000-0002-3078-2627Gerardo Garcia3https://orcid.org/0000-0002-3007-8998Durrell Institute of Conservation and Ecology, School of Anthropology and Conservation, University of Kent, Canterbury, UKDurrell Institute of Conservation and Ecology, School of Anthropology and Conservation, University of Kent, Canterbury, UKDepartment of Environment and Natural Resources, Government of Bermuda, Flatts Village, BermudaChester Zoo, Chester, UKMonitoring of cryptic or threatened species poses challenges for population assessment and conservation, as imperfect detection gives rise to misleading inferences about population status. We used a dynamic occupancy model that explicitly accounted for occupancy, colonization, local extinction and detectability to assess the status of the endemic Critically Endangered Bermuda skink Plestiodon longirostris. During 2015–2017, skinks were detected at 13 of 40 surveyed sites in Bermuda, two of which were new records. Ten observation-level and site-specific covariates were used to explore drivers of occupancy, colonization, extinction and detectability. Sites occupied by skinks tended to be islands with rocky coastal habitat and prickly pear cacti; the same variables were also associated with reduced risk of local extinction. The presence of seabirds appeared to encourage colonization, whereas the presence of cats had the opposite effect. The probability of detection was p = 0.45, and on average, five surveys were needed to reliably detect the presence of skinks with 95% certainty. However, skinks were unlikely to be detected on sites with cat and rat predators. Dynamic occupancy models can be used to elucidate drivers of occupancy dynamics, which in turn can inform species conservation management. The survey effort needed to determine population changes over time can be derived from estimates of detectability.https://www.cambridge.org/core/product/identifier/S0030605321000843/type/journal_articleBermuda skinkconservationdynamic occupancy modellingPlestiodon longirostrispopulation monitoringreptile |
| spellingShingle | Heléna Turner Richard A. Griffiths Mark E. Outerbridge Gerardo Garcia Dynamic occupancy modelling to determine the status of a Critically Endangered lizard Oryx Bermuda skink conservation dynamic occupancy modelling Plestiodon longirostris population monitoring reptile |
| title | Dynamic occupancy modelling to determine the status of a Critically Endangered lizard |
| title_full | Dynamic occupancy modelling to determine the status of a Critically Endangered lizard |
| title_fullStr | Dynamic occupancy modelling to determine the status of a Critically Endangered lizard |
| title_full_unstemmed | Dynamic occupancy modelling to determine the status of a Critically Endangered lizard |
| title_short | Dynamic occupancy modelling to determine the status of a Critically Endangered lizard |
| title_sort | dynamic occupancy modelling to determine the status of a critically endangered lizard |
| topic | Bermuda skink conservation dynamic occupancy modelling Plestiodon longirostris population monitoring reptile |
| url | https://www.cambridge.org/core/product/identifier/S0030605321000843/type/journal_article |
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