ORCID Profile
0000-0001-8148-8762
Current Organisation
James Cook University
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Publisher: Wiley
Date: 10-08-2015
DOI: 10.1111/JFB.12748
Abstract: Comparisons of three sets of surveys in the Ria Formosa Lagoon, Portugal, over a 13 year period (2001-2002, 2008-2009 and 2010-2013) revealed significant population fluctuations in at least one of the two seahorse (Hippoc inae) species living there, and that those fluctuations were potentially associated with habitat changes in the lagoon. After a significant decline between the first two survey periods (2001-2002 v. 2008-2009), long-snouted seahorse Hippoc us guttulatus populations increased significantly between 2008-2009 surveys and new 2010-2013 surveys. There were no significant differences in H. guttulatus populations between the 2001-2002 and 2010-2013 surveys. In contrast, there were no significant differences in short-snouted seahorse Hippoc us hippoc us densities among the 16 sites surveyed throughout the three s ling periods, although the ability to detect any change was h ered by the low densities of this species in all time periods. Fluctuations in H. guttulatus densities were positively correlated with the percentage of holdfast coverage, but with none of the other environmental variables tested. These results highlight the importance of holdfast availability in maintaining stable seahorse populations. While population fluctuations are certainly more promising than a consistent downward decline, such extreme fluctuations observed for seahorses in the Ria Formosa Lagoon could still leave these two species vulnerable to any additional stressors, particularly during low density periods.
Publisher: Springer Science and Business Media LLC
Date: 18-05-2012
Publisher: Public Library of Science (PLoS)
Date: 31-03-2016
Publisher: Springer Science and Business Media LLC
Date: 06-2010
Publisher: Canadian Science Publishing
Date: 08-2006
DOI: 10.1139/Z06-102
Abstract: Orientation mechanisms allow animals to spend minimal time in hostile areas while reaching needed resources. Identification of the specific mechanism used by an animal can be difficult, but examining an animal's path in familiar and unfamiliar areas can provide clues to the type of mechanism in use. Semiaquatic turtles are known to use a homing mechanism in familiar territory to locate their home lake while on land, but little is known about their ability to locate habitat in unfamiliar territory. We tested the tortuosity and orientation of 60 eastern painted turtles ( Chrysemys picta picta (Schneider, 1783)). We released turtles at 20 release points located at five distances and in two directions from two unfamiliar lakes. Turtle trails were quite straight (fractal dimension between 1.1 and 1.025) but were not oriented towards water from any distance (V-test u 0.72 P 0.1). Turtles maintained their initially chosen direction but either could not detect water or were not motivated to reach it. Furthermore, paths were straighter at larger spatial scales than at smaller spatial scales, which could not have occurred if the turtles had been using a correlated random walk. Turtles must therefore be using a reference stimulus for navigation even in unfamiliar areas.
Publisher: Wiley
Date: 26-04-2011
DOI: 10.1111/J.1095-8649.2011.02983.X
Abstract: Artificial marking and tagging techniques have been used to study movement, population dynamics, behaviour, ecology, survival and growth of at least 25 syngnathid species. External necklace-style tags and injection of visible implant elastomer have been the most used techniques, uniquely identifying hundreds of in idual syngnathids to study population dynamics, mortality, behaviour, ecology and growth in at least 13 and 12 species, respectively. Only two studies, both on larger syngnathid species, have tested the use of internal or electronic tags. This new case study reveals that dummy tags, weighing up to 6% of in idual body mass, have minimal effect on normal ex situ behaviour of the long-snouted seahorse Hippoc us guttulatus, a smaller syngnathid. In paired aquarium trials, tags did not affect movement, holdfast use or general behavioural state, and only had a short-term effect (1 day) on vertical orientation. Tagged H. guttulatus gained more mass during the 5 day trials, a result which warrants further exploration but indicates that tags did not reduce feeding. This study shows promise for using electronic tagging to study H. guttulatus and similarly sized syngnathids in the wild.
Publisher: Springer Science and Business Media LLC
Date: 19-06-2017
DOI: 10.1038/NCLIMATE3322
Publisher: Public Library of Science (PLoS)
Date: 10-06-2015
Publisher: Springer Science and Business Media LLC
Date: 05-07-2022
DOI: 10.1038/S41467-022-30991-4
Abstract: Climate change is expected to profoundly affect key food production sectors, including fisheries and agriculture. However, the potential impacts of climate change on these sectors are rarely considered jointly, especially below national scales, which can mask substantial variability in how communities will be affected. Here, we combine socioeconomic surveys of 3,008 households and intersectoral multi-model simulation outputs to conduct a sub-national analysis of the potential impacts of climate change on fisheries and agriculture in 72 coastal communities across five Indo-Pacific countries (Indonesia, Madagascar, Papua New Guinea, Philippines, and Tanzania). Our study reveals three key findings: First, overall potential losses to fisheries are higher than potential losses to agriculture. Second, while most locations ( 2/3) will experience potential losses to both fisheries and agriculture simultaneously, climate change mitigation could reduce the proportion of places facing that double burden. Third, potential impacts are more likely in communities with lower socioeconomic status.
Publisher: Wiley
Date: 26-04-2012
DOI: 10.1002/AQC.2238
Publisher: Springer Science and Business Media LLC
Date: 15-08-2013
No related grants have been discovered for Iain Caldwell.