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Chapter 16 - The Past and Future Ecologies of Australasian Kelp Forests
- Edited by Stephen J. Hawkins, Marine Biological Association of the United Kingdom, Plymouth, Katrin Bohn, Louise B. Firth, University of Plymouth, Gray A. Williams, The University of Hong Kong
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- Book:
- Interactions in the Marine Benthos
- Published online:
- 07 September 2019
- Print publication:
- 29 August 2019, pp 414-430
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Summary
While constant change characterises ecology, subtidal ecologists seem set to take a deep dive in to the biological processes that accelerate and compensate for environmental change. Similar to the technological and collaborative progress that benefited the present generation of authors, continuing progress may assist future generations of subtidal ecologists to figure out why kelp forests are characterised by global mosaics of long-term loss, gain and stasis. Where and how might kelp decline or flourish or simply persist future ocean change? Our review takes a biogeographic perspective to synthesise ecological patterns and the processes that create them. On this basis, we consider the modification of ecological processes by oceans undergoing physical and chemical change and, as a result, consider their future ecology. We find that future oceans will make life beyond the capacity of kelp to exist on many coasts, but not all coasts will be beyond the capacity of a kelp’s life. Consequently, this review provides a sign post for future research into the future decline or persistence or even increase of kelp forests.
Chapter 28 - Marine reserves in New Zealand: ecological responses to protection and network design
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- By Nick Shears, University of Auckland, Hannah L. Thomas, UNEP World Conservation Monitoring Centre, Cambridge, United Kingdom
- Edited by Adam Stow, Macquarie University, Sydney, Norman Maclean, University of Southampton, Gregory I. Holwell, University of Auckland
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- Book:
- Austral Ark
- Published online:
- 05 November 2014
- Print publication:
- 22 December 2014, pp 600-623
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Summary
Summary
Marine reserves are simple management tools that exclude extractive and destructive human activities from areas of the ocean. Given that fishing is one of the greatest impacts in most coastal ecosystems, networks of marine reserves are recognised as a core part of implementing ecosystem-based management in marine systems. Research in New Zealand marine reserves has contributed disproportionately to the global understanding of how species and ecosystems respond to marine reserve protection. We use examples from New Zealand to demonstrate the unequivocal role that marine reserves play in protecting exploited species within their boundaries, and how the recovery of exploited species can have wider conservation and fisheries value through indirect mechanisms and the movement of individuals from reserves. Progress towards developing a comprehensive and representative network of marine reserves in New Zealand has been slow because of a lack of political will, marine protected area legislation, and clear scientific guidance on marine reserve network design. Based on progress in designing networks of marine reserves internationally, and their demonstrated role in protecting biodiversity, we recommend a set of scientific guidelines to aid future development of marine reserves networks in New Zealand, and recommend that such networks be at the core of future marine spatial planning processes.
Introduction
Marine reserves are areas of the ocean that are protected from all extractive and destructive human activities (Lubchenco et al. 2003). They are often referred to as ‘no-take’ marine reserves as fishing is the main activity that is typically eliminated from a particular stretch of coast when a marine reserve is established. Given that fishing is the most widespread and historic human impact in coastal environments worldwide (Jackson et al. 2001) marine reserves provide a simple management tool to protect defined areas of the ocean from the impacts of fishing. While management of many fisheries is improving (Worm et al. 2009), there have been widespread calls to increase the level of protection for marine species through the implementation of networks of marine reserves worldwide (Wood et al. 2008). Fishing has a myriad of impacts on species as well as ecosystems through habitat disturbance and changes to food webs (Dayton et al. 2003). While marine reserves are not a panacea, as humans have a wide variety of impacts on marine ecosystems, they can protect the species and ecosystems within their boundaries from the effects of fishing.
Trajectories of spiny lobster Jasus edwardsii recovery in New Zealand marine reserves: is settlement a driver?
- DEBBIE J. FREEMAN, ALISON B. MACDIARMID, RICHARD B. TAYLOR, ROBERT J. DAVIDSON, ROGER V. GRACE, TIM R. HAGGITT, SHANE KELLY, NICK T. SHEARS
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- Journal:
- Environmental Conservation / Volume 39 / Issue 3 / September 2012
- Published online by Cambridge University Press:
- 01 June 2012, pp. 295-304
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Monitoring species’ response in marine protected areas is important for informing both the management of those areas and the establishment of additional protected areas. Populations of spiny lobsters Jasus edwardsii were monitored in eight New Zealand marine reserves for up to 34 years. The populations displayed highly variable responses to protection. While a few showed rapid (within 1–2 years of protection) increases in abundance, others showed little response even after a decade of protection. Some reserves displayed little initial recovery, then a sudden increase following several years of protection, while others displayed significant declines in abundance following initial recovery. Marine reserves located in areas with initially high densities of juveniles tended to have rapid recovery, but aspects of reserve design had no significant influence on the recovery rate. Variability among recovery trajectories also suggests that supply-side dynamics may be a key driver of lobster recovery. Densities of legal-sized lobsters were positively correlated with reserve age, but the abundance of juvenile lobsters increased in all but one reserve, indicating enhanced recruitment, survival and/or movement of juvenile lobsters into reserves. It is important to consider the placement of reserves, with respect to potential levels of larval supply, when establishing marine reserves for either conservation or fisheries management purposes and for evaluating their effectiveness.
Reconciling conflict between the direct and indirect effects of marine reserve protection
- NICK T. SHEARS, DAVID J. KUSHNER, STEPHEN L. KATZ, STEVEN D. GAINES
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- Journal:
- Environmental Conservation / Volume 39 / Issue 3 / September 2012
- Published online by Cambridge University Press:
- 16 April 2012, pp. 225-236
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No-take marine reserves directly promote the recovery of predatory species, which can have negative indirect effects on prey populations in reserves. When harvesting also occurs on prey species there is potential conflict between the direct and indirect effects of protection, and reserves may not have conservation benefits for prey species. For example, sea urchins are fished in many regions, but may decline in reserves due to increased predation rates. To investigate this potential conflict, this paper compares density, size, biomass and reproductive potential of both a harvested and an unharvested urchin species between a long-term reserve and unprotected sites in California. Consistent with density-mediated indirect interactions, densities of the unharvested species were 3.4-times higher at unprotected sites compared to reserve sites. However, for the harvested species, densities were comparable between reserve and unprotected sites. Both species were consistently larger at reserve sites, and the biomass and reproductive potential of the harvested species was 4.8- and 7.0-times higher, respectively, than at unprotected sites. This is likely due to differences in size-selectivity between harvesting and predators, and potential compensatory effects of predators. While the generality of these effects needs to be tested, these results suggest mechanisms whereby reserves can benefit both predator and prey species.
2 - ECOLOGY – Ecological effects of marine protected areas: conservation, restoration, and functioning
- from Part II - Effects of marine protected areas
- Edited by Joachim Claudet, Centre National de la Recherche Scientifique (CNRS), Paris
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- Book:
- Marine Protected Areas
- Published online:
- 05 August 2012
- Print publication:
- 29 September 2011, pp 37-71
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Summary
Introduction
Human-induced disturbance, e.g., through unsustainable fishery activities, can affect the ecology of coastal areas (Jackson et al., 2001; Lotze et al., 2006) and reduce the associated goods and services required for human welfare (Worm et al., 2006). Major concerns are rising over observed declines in the abundance of particular species as well as reductions in functional diversity and changes in food web structure (Pauly et al., 1998; Micheli and Halpern, 2005; Villéger et al., 2010). As a result, the conservation and restoration of marine biodiversity and functions is a major concern (Balmford et al., 2005). Marine protected areas (MPAs) are recommended to promote the recovery of exploited populations and conserve or restore habitats, ecosystems, and biodiversity (Lubchenco et al., 2003). Marine protected areas have also been recommended as tools for ecosystem-based management (EBM) of marine resources (Pauly et al., 2002; Halpern et al., 2010) and for restoration of ecosystem function (Mumby et al., 2007; Mouillot et al., 2008). However, some studies have failed to detect significant differences in ecological response variables between no-take and reference areas, or have criticized the design of existing studies, fuelling the view that the importance of MPAs as a management tool may have been overstated (Hilborn et al., 2004; Murawski et al., 2005; Osenberg et al., 2006).
Some attempts have been made recently to generalize the ecological effects of MPAs (Mosquera et al., 2000; Côté et al., 2001; Halpern, 2003; Micheli et al., 2004; Guidetti and Sala, 2007; Claudet et al., 2008; García-Charton et al., 2008; Harmelin-Vivien et al., 2008; Lester and Halpern, 2008; Lester et al., 2009; Molloy et al., 2009; Claudet et al., 2010). However, ecological effects can vary both in direction and magnitude (Micheli et al., 2004; Claudet et al., 2008; Guidetti et al., 2008; Lester et al., 2009; Molloy et al., 2009; Claudet et al., 2010). This heterogeneity in response to protection may stem from differences in the design or age of MPAs, life histories of focal taxa, the socio-cultural context within which MPAs are established, or a combination of these effects.