Ecosystem modelling provides clues to understanding ecological tipping points
| dc.contributor.author | Plagányi, Éva E | |
| dc.contributor.author | Ellis, Nick | |
| dc.contributor.author | Blamey, Laura K | |
| dc.contributor.author | Morello, Elisabetta B | |
| dc.contributor.author | Norman-Lopez, Anna | |
| dc.contributor.author | Robinson, William M L | |
| dc.contributor.author | Sporic, Miriana | |
| dc.contributor.author | Sweatman, Hugh | |
| dc.date.accessioned | 2016-03-14T11:20:07Z | |
| dc.date.available | 2016-03-14T11:20:07Z | |
| dc.date.issued | 2014 | |
| dc.date.updated | 2016-03-14T11:13:25Z | |
| dc.description.abstract | Ecological thresholds, associated with abrupt changes in the state and organisation of ecosystems, challenge both scientists and managers. Adaptive response to such changes, and planning for their occurrence, requires an understanding of the underlying drivers and system responses as well as appropriate monitoring. In addition to field studies, modelling can advance our ability to anticipate or deal with such major ecosystem shifts. Here, we used an existing multispecies model with smooth continuous functions that were modified to include thresholds representing 3 alternative scenarios of predator responses when prey numbers drop below a critical threshold: (I) no threshold-like response; (II) an abrupt decrease in breeding success by 90%, and (III) an abrupt halving of adult survival. Second, we analysed field observations from 3 independent marine case studies (abalone, starfish, penguins) for evidence of abrupt non-linear responses of predators to changes in abundance of principal prey. Third, we compared the model output with empirical results and tested (using both a statistical method and by fitting multispecies models) the 3 alternative response scenarios. With this approach, we found evidence for nonlinear changes in population parameters (such as survival rate) of predators as prey numbers declined below critical thresholds. As an example of the potential for this approach to inform management, we found that abundances of a range of marine predators become more variable as prey numbers decline, which may be a useful indicator that a system is approaching a tipping point. | en_ZA |
| dc.identifier | http://dx.doi.org/10.3354/meps10909 | |
| dc.identifier.apacitation | Plagányi, É. E., Ellis, N., Blamey, L. K., Morello, E. B., Norman-Lopez, A., Robinson, W. M. L., ... Sweatman, H. (2014). Ecosystem modelling provides clues to understanding ecological tipping points. <i>Marine Ecology Progress Series</i>, http://hdl.handle.net/11427/17765 | en_ZA |
| dc.identifier.chicagocitation | Plagányi, Éva E, Nick Ellis, Laura K Blamey, Elisabetta B Morello, Anna Norman-Lopez, William M L Robinson, Miriana Sporic, and Hugh Sweatman "Ecosystem modelling provides clues to understanding ecological tipping points." <i>Marine Ecology Progress Series</i> (2014) http://hdl.handle.net/11427/17765 | en_ZA |
| dc.identifier.citation | Plagányi, É. E., Ellis, N., Blamey, L. K., Morello, E. B., Norman-Lopez, A., Robinson, W., ... & Sweatman, H. (2014). Ecosystem modelling provides clues to understanding ecological tipping points. Marine Ecology Progress Series, 512, 99-113 | en_ZA |
| dc.identifier.issn | 0171-8630 | en_ZA |
| dc.identifier.ris | TY - Journal Article AU - Plagányi, Éva E AU - Ellis, Nick AU - Blamey, Laura K AU - Morello, Elisabetta B AU - Norman-Lopez, Anna AU - Robinson, William M L AU - Sporic, Miriana AU - Sweatman, Hugh AB - Ecological thresholds, associated with abrupt changes in the state and organisation of ecosystems, challenge both scientists and managers. Adaptive response to such changes, and planning for their occurrence, requires an understanding of the underlying drivers and system responses as well as appropriate monitoring. In addition to field studies, modelling can advance our ability to anticipate or deal with such major ecosystem shifts. Here, we used an existing multispecies model with smooth continuous functions that were modified to include thresholds representing 3 alternative scenarios of predator responses when prey numbers drop below a critical threshold: (I) no threshold-like response; (II) an abrupt decrease in breeding success by 90%, and (III) an abrupt halving of adult survival. Second, we analysed field observations from 3 independent marine case studies (abalone, starfish, penguins) for evidence of abrupt non-linear responses of predators to changes in abundance of principal prey. Third, we compared the model output with empirical results and tested (using both a statistical method and by fitting multispecies models) the 3 alternative response scenarios. With this approach, we found evidence for nonlinear changes in population parameters (such as survival rate) of predators as prey numbers declined below critical thresholds. As an example of the potential for this approach to inform management, we found that abundances of a range of marine predators become more variable as prey numbers decline, which may be a useful indicator that a system is approaching a tipping point. DA - 2014 DB - OpenUCT DP - University of Cape Town J1 - Marine Ecology Progress Series LK - https://open.uct.ac.za PB - University of Cape Town PY - 2014 SM - 0171-8630 T1 - Ecosystem modelling provides clues to understanding ecological tipping points TI - Ecosystem modelling provides clues to understanding ecological tipping points UR - http://hdl.handle.net/11427/17765 ER - | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11427/17765 | |
| dc.identifier.uri | http://www.int-res.com/abstracts/meps/v512/p99-113/ | |
| dc.identifier.vancouvercitation | Plagányi ÉE, Ellis N, Blamey LK, Morello EB, Norman-Lopez A, Robinson WML, et al. Ecosystem modelling provides clues to understanding ecological tipping points. Marine Ecology Progress Series. 2014; http://hdl.handle.net/11427/17765. | en_ZA |
| dc.language | eng | en_ZA |
| dc.publisher | Inter Research | en_ZA |
| dc.publisher.department | Marine Resource Assessment and Management Group | en_ZA |
| dc.publisher.faculty | Faculty of Science | en_ZA |
| dc.publisher.institution | University of Cape Town | |
| dc.relation.ispartofseries | Marine Ecology Progress Series | en_ZA |
| dc.source | Marine Ecology Progress Series | en_ZA |
| dc.source.uri | http://www.int-res.com/journals/meps/meps-home/ | |
| dc.subject.other | Abrupt change | |
| dc.subject.other | Ecological thresholds | |
| dc.subject.other | Adaptive management | |
| dc.subject.other | Trophodynamics | |
| dc.subject.other | Intermediate complexity model | |
| dc.subject.other | Non-linear responses | |
| dc.title | Ecosystem modelling provides clues to understanding ecological tipping points | en_ZA |
| dc.type | Journal Article | en_ZA |
| uct.subject.keywords | Abrupt change; Ecological thresholds; Adaptive management; Trophodynamics; Intermediate complexity model; Non-linear responses | en_ZA |
| uct.type.publication | Research | en_ZA |
| uct.type.resource | Article | en_ZA |