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Sea Urchin Removal as a Tool, Not a Solution: Practical Lessons for Kelp Restoration in Aotearoa New ZealandNARA Subscribed
The increasing awareness of the extent of urchin barrens and impacts of sea urchin overgrazing on rocky reefs in Aotearoa New Zealand has led to a rapid increase in the use of sea urchin removal as a tool for kelp forest restoration. Here, we review these restoration projects, focusing on three case studies, with the aim to provide context on what urchin removal does and does not achieve and guidance on when, where and how it...
Long‐term warming and record‐breaking marine heatwaves in the Hauraki Gulf, northern New ZealandNARA Subscribed
As global oceans warm, long‐term temperature records are critical in understanding and interpreting warming trends and the significance of marine heatwaves (MHWs) in coastal environments. Daily measurements of sea surface temperature (SST) have been taken since 1967 at the Leigh Marine Laboratory, Hauraki Gulf, northern New Zealand. We analyse long‐term trends in SST anomalies and MHWs at Leigh from 1967 to 2023. We find a sig...
Estimating the extent of urchin barrens and kelp forest loss in northeastern Aotearoa, New ZealandNARA Subscribed
On shallow rocky reefs in northeastern Aotearoa, New Zealand, urchin barrens are indicators of the ecosystem effects of overfishing reef predators. Yet, information on their extent and variability is lacking. We use aerial imagery to map the urchin barrens and kelp forests on reefs ( 2 of barrens exist across the region. This demonstrates the widespread nature of barrens, the potential long‐term effectiveness of no‐take marine...
The value of no-take marine protected areas (MPAs) in providing fisheries-independent information to evaluate the status of adjacent fish stocks is increasingly being recognised. However, to ensure robust assessments of fisheries using this approach, MPAs need to be representative of the wider fished area and sampling should include multiple MPA and fished locations spanning the area of interest. The spiny lobster Jasus edward...
Morphological variation of the kelp Ecklonia radiata in northeastern New Zealand and across its Australasian rangeNARA Subscribed
Understanding the drivers of morphological plasticity, a key mechanism allowing species to flourish under a range of conditions, can provide important information on how a species will adapt to climate-change. The kelp Ecklonia radiata is the dominant canopy-forming macroalgae in temperate Australasia, occurring across a wide environmental range. Previous assessments of morphological variation across Australasia have not inclu...
Marine heatwave promotes population expansion of the invasive ascidian Symplegma brakenhielmiNARA Subscribed
The global increase in frequency and severity of marine heatwaves (MHWs) is highlighting the impact these extreme climatic events can have on marine ecosystems. Throughout the summer of 2021/2022 northeastern Aotearoa/New Zealand suffered an unprecedented MHW. Worst impacted areas, such as the semi-enclosed Te Moananui-ā-Toi/Tīkapa Moana/Hauraki Gulf, experienced more than three continual months of temperatures at or above the...
Marine protected areas have long been proposed as a key tool to restore lost food web interactions and increase the resilience of ecosystems to climate change impacts. However, a changing climate can result in the arrival of new species or differentially affect native species, which can alter ecosystem dynamics and make it difficult to predict how ecosystems will respond to protection. The long-spined sea urchin Centrostephanu...
Robust monitoring data provides important information on ecosystem responses to anthropogenic stressors; however, traditional monitoring methodologies, which rely heavily on time in the field, are resource intensive. Consequently, trade-offs between data metrics captured and overall spatial and temporal coverage are necessary to fit within realistic monitoring budgets and timeframes. Recent advances in remote sensing technolog...
Sea Urchin Removal as a Tool for Macroalgal Restoration: A Review on Removing “the Spiny Enemies”OA Marine
Kelp and macroalgal forests provide the ecological foundations of many temperate rocky reef ecosystems, but have regionally declined, often due to sea urchin overgrazing and the formation of urchin barrens. Sea urchin removal has long been used to investigate kelp-sea urchin dynamics and is increasingly being promoted for kelp forest restoration. In this review, we assess the methods and outcomes of sea urchin removal experime...
Coastal darkening substantially limits the contribution of kelp to coastal carbon cyclesNARA Subscribed
Macroalgal‐dominated habitats are rapidly gaining recognition as important contributors to marine carbon cycles and sequestration. Despite this recognition, relatively little is known about the production and fate of carbon originating from these highly productive ecosystems, or how anthropogenic‐ and climate‐related stressors affect the role of macroalgae in marine carbon cycles. Here, we examine the impact of increasing turb...
Ecosystem patterning can arise from environmental heterogeneity, biological feedbacks that produce multiple persistent ecological states, or their interaction. One source of feedbacks is density‐dependent changes in behaviour that regulate species interactions. By fitting state‐space models to large‐scale (~500 km) surveys on temperate rocky reefs, we find that behavioural feedbacks best explain why kelp and urchin barrens for...
Nutrient enrichment offsets the effects of low light on growth of the kelp Ecklonia radiataNARA Subscribed
Increased input of terrigenous matter and pollution into coastal marine ecosystems results in both a decline in benthic irradiance and an influx of nutrients. Though low light conditions have been demonstrated to have adverse effects on benthic primary producers, associated increases in nutrients may alleviate some of this stress by enhancing growth and productivity. We examined the interactive effect of low light and increase...
Morphology and photosynthetic response of the kelp Ecklonia radiata across a turbidity gradientNARA Subscribed
Increasing turbidity in coastal waters reduces benthic irradiance levels and consequently poses a fundamental threat to benthic primary producers and the food webs they support. It is therefore necessary to better understand how important primary producers, such as kelp, can adapt both physiologically and morphologically to these declining light conditions. This study examines how variation in turbidity influences the morpholo...
Species interactions are integral drivers of community structure and can change from competitive to facilitative with increasing environmental stress. In subtidal marine ecosystems, however, interactions along physical stress gradients have seldom been tested. We observed seaweed canopy interactions across depth and latitudinal gradients to test whether light and temperature stress structured interaction patterns. We also quan...