A framework for the resilience of seagrass ecosystems

Unsworth, Richard K. F.; Collier, Catherine; Waycott, Michelle; McKenzie, Len J.; Cullen-Unsworth, Leanne C.

doi:10.1016/j.marpolbul.2015.08.016

Cited by 198 publications

(177 citation statements)

References 163 publications

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“…The present study found strong correlative evidence that increasing presence of herbivory is associated with reduced epicover suggesting increased leaf turnover and higher resultant levels of resistance to potential impacts (e.g., poor water quality) (Unsworth et al, 2015). Attached flora or fauna on seagrass leaves has the potential to reduce photosynthetic rate due to shading (Oh et al, 2009).…”

Section: Discussionmentioning

confidence: 55%

“…The present study recorded that such attached material can cover over 60% of the leaf area. This shading reduces the capacity of the plant to resist the effect of any further shading from problems, such as periods of poor water quality (Unsworth et al, 2015). We recorded a significant negative correlation between the percentage of leaves bitten and total epiphyte and epibiont coverage.…”

Section: Discussionmentioning

confidence: 73%

“…Seagrass meadows are a globally important ecosystem under significant anthropogenic threat (Waycott et al, 2009). The management of these ecosystems requires a better understanding of the functional ecological processes that ultimately confer resilience upon it (Unsworth et al, 2015) and their interactions throughout the seascape.…”

Section: Introductionmentioning

confidence: 99%

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Habitat Configuration Alters Herbivory across the Tropical Seascape

et al. 2017

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There exists increasing evidence that top-down ecological processes, such as herbivory are key in controlling marine ecosystems and their community structure. Herbivory has the potential to be altered by numerous environmental and ecological factors that operate at a variety of temporal and spatial scales, one such spatial factor is the influence of the marine landscape. We know little about how ecological processes, such as herbivory change throughout the marine landscape and how the effects of these processes cascade. This is because most landscape scale studies observe species richness and abundance patterns. In terrestrial systems the landscape is well documented to influence ecological processes, but empirical evidence of this is limited in marine systems. In tropical seagrass meadows direct herbivory by parrotfish can be readily observed due to the clear hemispherical bite marks they leave on the seagrass. As with herbivory in other systems, this leaf consumption is thought to assist with leaf turnover, positively influencing leaf growth. Changes in its rate and extent are therefore likely to influence the characteristics of the plant. The faunal communities of seagrass meadows alter with respect to changes in the landscape, particularly with respect to connectivity to adjacent habitats. It might therefore be expected that a key ecological process, such as herbivory will change with respect to habitat configuration and have cascading impacts upon the status of the seagrass. In the present study we examined indirect evidence of parrotfish grazing throughout the marine landscape and assessed this relative to plant condition. Seagrasses in locations of close proximity to mangroves were found to have double the amount of parrotfish grazing than sites away from mangroves. Evidence of herbivory was also found to be strongly and significantly negatively correlated to the abundance of plant attached epicover. The decreased epicover in the presence of elevated herbivory suggests increased leaf turnover. These results indicate that seagrass may have higher levels of ecosystem resilience in the presence of mangroves. Our research highlights how ecological processes can change throughout the marine landscape with cascade impacts on the resilience of the system.

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Section: Discussionmentioning

confidence: 55%

Section: Discussionmentioning

confidence: 73%

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Habitat Configuration Alters Herbivory across the Tropical Seascape

et al. 2017

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“…These migrations are driven by biological (e.g., the need to mate) or ecological (e.g., low resources or optimal/suboptimal climate) factors (Gilmore et al, 2007;Robinson et al, 2009;Lascelles et al, 2014) and have important roles in habitat connectivity (Unsworth et al, 2015;Tol et al, 2017). For example, in the Coral Sea, off the northeast coast of Australia, nesting green sea turtles (Chelonia mydas) tagged in Australia migrate to international feeding grounds in New Caledonia and back to their nesting grounds in Australia, crossing state, national, and international boundaries as they migrate (Read et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Protecting Migratory Species in the Australian Marine Environment: A Cross-Jurisdictional Analysis of Policy and Management Plans

et al. 2018

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Marine migratory species are difficult to manage because animal movements can span large areas and are unconstrained by jurisdictional boundaries. We reviewed policy and management plans associated with four case studies protected under the Australian Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act 1999) in order to identify the coherence of policy and management plans for managing marine migratory species in Australia. Environmental policies (n = 23) and management plans (n = 115) relevant to marine turtles, dugongs, humpback whales, and migratory shorebirds were reviewed. Few of the reviewed policies (n = 7) listed protected species and even fewer (n = 4) listed protected marine migratory species. Marine turtles were most represented in the reviewed policies (n = 7), while migratory shorebirds were most represented in management plans (n = 59). Policies and management plans were much more likely to identify relationships to other policies or plans within the same jurisdiction than to different jurisdictions. The EPBC Act 1999 served as the central link between reviewed policies and plans, but the requirements of that Act were weakly integrated into the other documents. This weak integration and the biases toward specific migratory species in environmental policies and management plans are detrimental to the conservation of these Matters of National Environmental Significance in Australia. Any changes to the EPBC Act 1999 will affect all environmental policy and management plans in Australia and highlights a need for cooperative, multi-level governance of migratory species. Our findings may have relevance to the conservation of marine migratory species in a broader international context.

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“…While monocultures or low-diversity systems may expand most rapidly following a stress-induced population collapse, diverse systems are more resilient (Stachowicz et al 2013;Gustafsson, Boström, and Unsworth 2013). Resilient seagrass communities are, in turn, easier to protect, manage, and restore (Unsworth et al 2015). This highlights the importance of understanding SAV diversity, both natural and restored as transplants or through seeding.…”

Section: Outlook For the Twenty-first Centurymentioning

confidence: 99%

Twenty-first century climate change and submerged aquatic vegetation in a temperate estuary: the case of Chesapeake Bay

Arnold

Zimmerman

Engelhardt

et al. 2017

Ecosyst Health Sustain

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Introduction: The Chesapeake Bay was once renowned for expansive meadows of submerged aquatic vegetation (SAV). However, only 10% of the original meadows survive. Future restoration efforts will be complicated by accelerating climate change, including physiological stressors such as a predicted mean temperature increase of 2-6°C and a 50-160% increase in CO 2 concentrations. Outcomes: As the Chesapeake Bay begins to exhibit characteristics of a subtropical estuary, summer heat waves will become more frequent and severe. Warming alone would eventually eliminate eelgrass (Zostera marina) from the region. It will favor native heat-tolerant species such as widgeon grass (Ruppia maritima) while facilitating colonization by non-native seagrasses (e.g., Halodule spp.). Intensifying human activity will also fuel coastal zone acidification and the resulting high CO 2 /low pH conditions may benefit SAV via a "CO 2 fertilization effect." Discussion: Acidification is known to offset the effects of thermal stress and may have similar effects in estuaries, assuming water clarity is sufficient to support CO 2 -stimulated photosynthesis and plants are not overgrown by epiphytes. However, coastal zone acidification is variable, driven mostly by local biological processes that may or may not always counterbalance the effects of regional warming. This precarious equipoise between two forcesthermal stress and acidification -will be critically important because it may ultimately determine the fate of cool-water plants such as Zostera marina in the Chesapeake Bay. Conclusion: The combined impacts of warming, coastal zone acidification, water clarity, and overgrowth of competing algae will determine the fate of SAV communities in rapidly changing temperate estuaries.

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A framework for the resilience of seagrass ecosystems

Cited by 198 publications

References 163 publications

Habitat Configuration Alters Herbivory across the Tropical Seascape

Habitat Configuration Alters Herbivory across the Tropical Seascape

Protecting Migratory Species in the Australian Marine Environment: A Cross-Jurisdictional Analysis of Policy and Management Plans

Twenty-first century climate change and submerged aquatic vegetation in a temperate estuary: the case of Chesapeake Bay

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