Stay close, but not too close: aerial image analysis reveals patterns of social distancing in seal colonies
Many species aggregate in dense colonies. Species-specific spatial patterns provide clues about how colonies are shaped by various (a)biotic factors, including predation, temperature regulation or disease transmission. Using aerial imagery, we examined these patterns in colonies on land of two sympa...
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| Format: | Article |
| Language: | English |
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The Royal Society
2023-08-01
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| Series: | Royal Society Open Science |
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| Online Access: | https://royalsocietypublishing.org/doi/10.1098/rsos.230269 |
| _version_ | 1797749135461318656 |
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| author | J. P. A. Hoekendijk A. Grundlehner S. Brasseur B. Kellenberger D. Tuia G. Aarts |
| author_facet | J. P. A. Hoekendijk A. Grundlehner S. Brasseur B. Kellenberger D. Tuia G. Aarts |
| author_sort | J. P. A. Hoekendijk |
| collection | DOAJ |
| description | Many species aggregate in dense colonies. Species-specific spatial patterns provide clues about how colonies are shaped by various (a)biotic factors, including predation, temperature regulation or disease transmission. Using aerial imagery, we examined these patterns in colonies on land of two sympatric seal species: the harbour seal and grey seal. Results show that the density of grey seals on land is twice as high as that of harbour seals. Furthermore, the nearest neighbour distance (NND) of harbour seals (median = 1.06 m) is significantly larger than that of grey seals (median = 0.53 m). Avoidance at small distances (i.e. social distancing) was supported by spatial simulation: when the observed seal locations were shuffled slightly, the frequency of the smallest NNDs (0–25 cm) increased, while the most frequently observed NNDs decreased. As harbour seals are more prone to infectious diseases, we hypothesize that the larger NNDs might be a behavioural response to reduce pathogen transmission. The approach presented here can potentially be used as a practical tool to differentiate between harbour and grey seals in remote sensing applications, particularly in low to medium resolution imagery (e.g. satellite imagery), where morphological characteristics alone are insufficient to differentiate between species. |
| first_indexed | 2024-03-12T16:14:54Z |
| format | Article |
| id | doaj.art-d1486b79cefa4a0aa7e87c2949f496f9 |
| institution | Directory Open Access Journal |
| issn | 2054-5703 |
| language | English |
| last_indexed | 2024-03-12T16:14:54Z |
| publishDate | 2023-08-01 |
| publisher | The Royal Society |
| record_format | Article |
| series | Royal Society Open Science |
| spelling | doaj.art-d1486b79cefa4a0aa7e87c2949f496f92023-08-09T07:05:25ZengThe Royal SocietyRoyal Society Open Science2054-57032023-08-0110810.1098/rsos.230269Stay close, but not too close: aerial image analysis reveals patterns of social distancing in seal coloniesJ. P. A. Hoekendijk0A. Grundlehner1S. Brasseur2B. Kellenberger3D. Tuia4G. Aarts5NIOZ Royal Netherlands Institute for Sea Research, 1790AB Den Burg, The NetherlandsWageningen University and Research, 6708PB Wageningen, The NetherlandsNIOZ Royal Netherlands Institute for Sea Research, 1790AB Den Burg, The NetherlandsDepartment of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USAEcole Polytechnique Fédérale de Lausanne (EPFL), 1950 Sion, SwitzerlandNIOZ Royal Netherlands Institute for Sea Research, 1790AB Den Burg, The NetherlandsMany species aggregate in dense colonies. Species-specific spatial patterns provide clues about how colonies are shaped by various (a)biotic factors, including predation, temperature regulation or disease transmission. Using aerial imagery, we examined these patterns in colonies on land of two sympatric seal species: the harbour seal and grey seal. Results show that the density of grey seals on land is twice as high as that of harbour seals. Furthermore, the nearest neighbour distance (NND) of harbour seals (median = 1.06 m) is significantly larger than that of grey seals (median = 0.53 m). Avoidance at small distances (i.e. social distancing) was supported by spatial simulation: when the observed seal locations were shuffled slightly, the frequency of the smallest NNDs (0–25 cm) increased, while the most frequently observed NNDs decreased. As harbour seals are more prone to infectious diseases, we hypothesize that the larger NNDs might be a behavioural response to reduce pathogen transmission. The approach presented here can potentially be used as a practical tool to differentiate between harbour and grey seals in remote sensing applications, particularly in low to medium resolution imagery (e.g. satellite imagery), where morphological characteristics alone are insufficient to differentiate between species.https://royalsocietypublishing.org/doi/10.1098/rsos.230269nearest neighbour distancedensityremote sensingPhoca vitulinaHalichoerus grypusherding behaviour |
| spellingShingle | J. P. A. Hoekendijk A. Grundlehner S. Brasseur B. Kellenberger D. Tuia G. Aarts Stay close, but not too close: aerial image analysis reveals patterns of social distancing in seal colonies Royal Society Open Science nearest neighbour distance density remote sensing Phoca vitulina Halichoerus grypus herding behaviour |
| title | Stay close, but not too close: aerial image analysis reveals patterns of social distancing in seal colonies |
| title_full | Stay close, but not too close: aerial image analysis reveals patterns of social distancing in seal colonies |
| title_fullStr | Stay close, but not too close: aerial image analysis reveals patterns of social distancing in seal colonies |
| title_full_unstemmed | Stay close, but not too close: aerial image analysis reveals patterns of social distancing in seal colonies |
| title_short | Stay close, but not too close: aerial image analysis reveals patterns of social distancing in seal colonies |
| title_sort | stay close but not too close aerial image analysis reveals patterns of social distancing in seal colonies |
| topic | nearest neighbour distance density remote sensing Phoca vitulina Halichoerus grypus herding behaviour |
| url | https://royalsocietypublishing.org/doi/10.1098/rsos.230269 |
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