Fiordland: the ecological basis for ecosystem management

Wing, Stephen R.; Jack, Lucy

doi:10.1080/00288330.2014.897636

Cited by 18 publications

(23 citation statements)

References 117 publications

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“…In contrast, Fiordland is a relatively pristine region with intact native forest catchments (Miller, Wing, & Hurd, ; Tallis, Wing, & Frew, ; Wing & Jack, ). Hence, there is a much lower likelihood that macroalgae biomass has been influenced by sedimentation or nutrient pollution from catchment runoff.…”

Section: Discussionmentioning

confidence: 99%

Organic matter derived from kelp supports a large proportion of biomass in temperate rocky reef fish communities: Implications for ecosystem‐based management

Udy

Wing

O’Connell-Milne

et al. 2019

Aquatic Conservation

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1. The relative availability of alternative organic matter sources directly influences trophic interactions within ecological communities. As differences in trophic ecology can alter the productivity of communities, understanding spatial variability in trophic structure, and the drivers of variability, is vital for implementing effective ecosystem-based management.2. Bulk stable isotope analysis (δ 13 C and δ 15 N) and mass balance calculations were used to examine patterns in the contribution of organic matter derived from macroalgae to food webs supporting temperate reef fish communities in two contrasting coastal waterways on the South Island of New Zealand: Fiordland and the Marlborough Sounds. Ten fish species common to both regions were compared, with up to 40% less organic matter from macroalgae supporting omnivorous species in the Marlborough Sounds. The largest differences in trophic position were found in those species exploited by fisheries.3. Furthermore, stratified surveys of abundance and species biomass combined with trophic position data were used to calculate regional differences in the contribution of macroalgae to whole fish communities in terms of density of biomass. In Fiordland, over 77% of the biomass of exploited reef fishes was supported by macroalgae, compared with 31% in the Marlborough Sounds. 4. Surveys of macroalgal density and species composition in the two regions indicated that regional differences in trophodynamics may be explained by a lack of macroalgal inputs to the food web in the Marlborough Sounds.5. The findings demonstrate large regional differences in the incorporation of benthic and pelagic sources of organic matter to food webs supporting reef fish communities, highlighting the need for ecosystem-based approaches to management to recognize spatial variability in primary production supporting coastal food webs.

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Section: Discussionmentioning

confidence: 99%

Organic matter derived from kelp supports a large proportion of biomass in temperate rocky reef fish communities: Implications for ecosystem‐based management

Udy

Wing

O’Connell-Milne

et al. 2019

Aquatic Conservation

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“…In order to sample wave-exposed and wave-sheltered sites within both fished and unfished areas, study sites in Fiordland were spread throughout the network of marine reserves in the southern Fiordland Marine Area. Site selection in Fiordland was based on kelp density data from previous monitoring reports (Wing and Jack 2014) and information on habitat types from a Fiordland wide habitat classification system (Wing et al 2007). The Fiordland network of marine reserves was established in 2005, though the Te Awaatu Channel reserve in Doubtful Sound has been established since 1993.…”

Section: Study Sitesmentioning

confidence: 99%

“…These relationships were investigated in two coastal waterway systems on the South Island, New Zealand: Marlborough Sounds and southern Fiordland. Both regions were characterized by extensive wave‐sheltered rocky reef habitats at the entrances of the Sounds, harboring kelp forests with similar reef fish and benthic invertebrate communities (Shears and Babcock , Wing and Jack ). Nevertheless, there were considerable regional differences in anthropogenic stressors, with evidence for land‐based stressors, influence of invasive species, frequency of warming events, and intensity of fishing pressure each more prevalent in the Marlborough Sounds (Handley ).…”

Section: Introductionmentioning

confidence: 99%

Regional differences in kelp forest interaction chains are influenced by both diffuse and localized stressors

et al. 2019

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On temperate rocky reefs, overexploitation of high‐trophic‐level omnivores can result in the decimation of kelp forest habitats by releasing sea urchin population networks from top‐down control. However, the local dynamics of the resulting trophic cascades are context‐dependent. Here, we investigate the community‐wide patterns associated with both diffuse stressors and localized protection of high‐trophic‐level omnivores in kelp forest ecosystems by comparing communities among marine reserves and fished areas in two contrasting regions in terms of fishing intensity and land‐based stressors, Fiordland and the Marlborough Sounds, New Zealand. We find higher densities of the potential sea urchin predators, red rock lobsters (Jasus edwardsii) and banded wrasse (Notolabrus fucicola), in the Fiordland region, and larger effect sizes of fishing on the exploited fish communities in the Marlborough Sounds. Patterns in sea urchin density were consistent with the idea that high‐trophic‐level species, such as large fish and rock lobsters, regulate sea urchin population density, with lower densities of Evechinus chloroticus observed inside marine reserves, in both regions. Nevertheless, densities of E. chloroticus were generally high (>3 m2) in the Marlborough Sounds, likely above a grazing threshold in both fished and reserve sites. The proportion of habitat where sea urchins were absent was 29% in Marlborough Sounds and 90% in Fiordland. Consequently, we observe 49% barren habitat in Fiordland vs. 70%, and a larger effect of fishing on kelp community structure, in the Marlborough Sounds, where fishing effect sizes and land‐based stressors were more severe. We propose that a combination of diffuse stressors including regional overexploitation of important sea urchin predators, sedimentation, and warming of coastal waters likely contributed to regional differences in the responses of trophic interaction chains to localized reductions in fishing within marine reserves. The present study highlights how physiologically stressed and modified kelp forest ecosystems are more susceptible to detrimental phase shifts at a regional spatial scale.

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“…Changes of this nature are especially apparent in kelp forest systems, where environmental changes wrought from coastal eutrophication, marine heat waves and proliferation of sea urchins have dramatically modified the distribution and abundance of kelp forests in many parts of the world (Dayton et al 1998, Wernberg et al 2016. As a consequence, elucidating the trophic structure of marine communities, and the sources of basal organic matter required to support them, is a vital component of effective ecosystem-based models for fisheries management and for predicting how changes to critical habitats such as kelp forests may affect the functioning of marine ecosystems (Persson et al 2014, Wing & Jack 2014, Wing et al 2015.…”

Section: Introductionmentioning

confidence: 99%

“…Here we were able to directly test these ideas by comparing the trophic architecture, origins and volume of organic matter supporting coastal fish communities from 2 contrasting regions, Fiordland and the Marlborough Sounds. Both regions are characterized by extensive wave-sheltered rocky reef habitats at the entrances of the sounds, harboring kelp forests with both giant kelp Macrocystis pyrifera and the common kelp Ecklonia radiata, as well as similar reef fish and benthic invertebrate communities (Shears & Babcock 2007, Wing & Jack 2014. Nevertheless, there have been declines reported in giant kelp forests in the Marlborough Sounds over the last 50 yr linked to marine heat waves (Hay 1990) and increases in fine sediment inputs (Handley 2016), and following the overharvesting of the sea urchin predators red rock lobster Jasus edwardsii and blue cod Parapercis colias (Davidson et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Regional differences in supply of organic matter from kelp forests drive trophodynamics of temperate reef fish

Udy¹,

Wing²,

O’Connell-Milne³

et al. 2019

Mar. Ecol. Prog. Ser.

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Regional differences in trophic structure and availability of alternate sources of basal organic matter to food webs can affect the volume of organic matter converted into fish biomass. The present study combined stable isotope analyses (δ 13 C and δ 15 N) with estimates of biomass density of 22 common reef fishes to compare supply of organic matter derived from macroalgae versus phytoplankton to reef fish communities among 30 sites distributed across Fiordland and the Marlborough Sounds, 2 contrasting regions in terms of land-based stressors on the South Island, New Zealand. Fish communities in the Marlborough Sounds were supported by food webs that incorporated less organic matter derived from macroalgae compared to those in Fiordland. Contribution of organic matter derived from macroalgae to fish biomass decreased with trophic level in the Marlborough Sounds, while fishes in Fiordland were supported by a more equal mixture of organic matter derived from phytoplankton and macroalgae among trophic levels. Total fish biomass density was 1.72 times higher in Fiordland, yet the fish community converted 2.91 times more organ ic matter to fish biomass, as a result of a higher proportion of biomass at high trophic levels. The observed patterns were consistent with limitation in supply of organic matter derived from macroalgae in the Marlborough Sounds, where extensive losses of kelp forest habitat linked to land-based stressors have been reported. The results highlight the importance of considering regional variability in basal organic matter source pools, particularly those produced from sensitive kelp forest habitats, when applying ecosystem-based approaches to managing coastal resources.

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Fiordland: the ecological basis for ecosystem management

Cited by 18 publications

References 117 publications

Organic matter derived from kelp supports a large proportion of biomass in temperate rocky reef fish communities: Implications for ecosystem‐based management

Organic matter derived from kelp supports a large proportion of biomass in temperate rocky reef fish communities: Implications for ecosystem‐based management

Regional differences in kelp forest interaction chains are influenced by both diffuse and localized stressors

Regional differences in supply of organic matter from kelp forests drive trophodynamics of temperate reef fish

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