Glynnis Nakai - Academia.edu (original) (raw)
Papers by Glynnis Nakai
Colonial Waterbirds, 1992
Survival at French Frigate Shoals, Hawaii KF.NNF. 1'11 K. N I E : I ' i I~\ h i h l E K ' , (; F ... more Survival at French Frigate Shoals, Hawaii KF.NNF. 1'11 K. N I E : I ' i I~\ h i h l E K ' , (; F .~K (: F. ti. l i~\ t .~u s 2. (; I. \ , N N I S 1.. N.,\ti..\il ANI) IILIANE K. M<:DEKMONI)' 11. S. Fish and M'ildlife Sei-vice 1 ' 0 Box 50167. Horiolulu. HI Yti850 'National Marine Fisheries Service. Southwest Fisheries Scieiic e (k i t e r , 2570 1)ole St.. HOIIOIIIIU. Hawaii 96XTL-2:KMi Abstract.-Frib.atebirds are known predators 01. sea turtle hatchlings at sevrral locations worldwide. At certain localities this predation might excerbate the already endangered status of these marine reptiles. French Frigate Shoals, Hawaii is where over 90% of all Hawaiian green turtle (Chelm~za my&) breeding occurs and is the site of a large Great Frigatebird (Fregala minor) colony. Frigatebird predation was not a factor in hatchling survival at this location. We found no evidence of green turtle hatchlings in the stomach contents of 200 Great Frigatebirds sampled during peak periods of hatchling
Restoration Ecology, 2016
The restoration of the Nisqually River Delta (Washington, U.S.A.) represents one of the largest e... more The restoration of the Nisqually River Delta (Washington, U.S.A.) represents one of the largest efforts toward reestablishing the ecosystem function and resilience of modified habitat in the Puget Sound, particularly for anadromous salmonid species. The opportunity for outmigrating salmon to access and benefit from the expansion of available tidal habitat can be quantified by several physical attributes, which are related to the ecological and physiological responses of juvenile salmon. We monitored a variety of physical parameters to measure changes in opportunity potential from historic, pre-restoration, and post-restoration habitat conditions at several sites across the delta. These parameters included channel morphology, water quality, tidal elevation, and landscape connectivity. We conducted fish catch surveys across the delta to determine if salmon was utilizing restored estuary habitat. Overall major channel area increased 42% and major channel length increased 131% from pre-to post-restoration conditions. Furthermore, the results of our tidal inundation model indicated that major channels were accessible up to 75% of the time, as opposed to 30% pre-restoration. Outmigrating salmon utilized this newly accessible habitat as quickly as 1 year post-restoration. The presence of salmon in restored tidal channels confirmed rapid post-restoration increases in opportunity potential on the delta despite habitat quality differences between restored and reference sites.
Transactions of the American Fisheries Society
In the context of delta restoration and its impact on salmonid rearing, success is best evaluated... more In the context of delta restoration and its impact on salmonid rearing, success is best evaluated based on whether out-migrating juvenile salmon can access and benefit from suitable estuarine habitat. Here, we integrated 3 years of post-restoration monitoring data including habitat availability, invertebrate prey biomass, and juvenile Chinook salmon (Oncorhynchus tshawytscha) physiological condition to determine whether individuals profited from the addition of 364 ha of delta habitat in South Puget Sound, Washington, United States. Productivity in the restored mudflat was comparable to reference sites 3 years after dike removal, surpassing a mean total of 6 million kJ energy from invertebrate prey. This resulted from the development of a complex network of tidal channels and a resurgence in dipteran biomass that was unique to the restoration area. Consequently, a notable shift in invertebrate consumption occurred between 2010 and 2011, whereby individuals switched from eating primarily amphipods to dipteran flies; however, dietary similarity to the surrounding habitat did not change from year to year, suggesting that this shift was a result of a change in the surrounding prey communities. Growth rates did not differ between restored and reference sites, but catch weight was positively correlated with prey biomass, where greater prey productivity appeared to offset potential density-dependent effects. These results demonstrate how the realized function of restoring estuarine habitat is functionally dependent. High prey productivity in areas with greater connectivity may support healthy juvenile salmon that are more likely to reach the critical size class for offshore survival.
Estuaries provide crucial foraging resources and nursery habitat for threatened populations of an... more Estuaries provide crucial foraging resources and nursery habitat for threatened populations of anadromous salmon. As such, there has been a global undertaking to restore habitat and tidal processes in modified estuaries. The foraging capacity of these ecosystems to support various species of out-migrating juvenile salmon can be quantified by monitoring benthic, terrestrial, and pelagic invertebrate prey communities. Here, we present notable trends in the availability of invertebrate prey at several sites within a restoring large river delta in Puget Sound, Washington, U.S.A. Three years after the system was returned to tidal influence, we observed substantial additions to amphipod, copepod, and cumacean abundances in newly accessible marsh channels (from 0 to roughly 5,000–75,000 individuals/m 2). In the restoration area, terrestrial invertebrate colonization was dependent upon vegetative cover, with dipteran and hymenopteran biomass increasing 3-fold between 1 and 3 years post-restoration. While the overall biodiversity within the restoration area was lower than in the reference marsh, estimated biomass was comparable to or greater than that found within the other study sites. This additional prey biomass likely provided foraging benefits for juvenile Chinook, chum, and coho salmon. Primary physical drivers differed for benthic, terrestrial, and pelagic invertebrates, and these invertebrate communities are expected to respond differentially depending on organic matter exchange and vegetative colonization. Restoring estuaries may take decades to meet certain success criteria, but our study demonstrates rapid enhancements in foraging resources understood to be used for estuary-dependent wildlife.
Colonial Waterbirds, 1992
Survival at French Frigate Shoals, Hawaii KF.NNF. 1'11 K. N I E : I ' i I~\ h i h l E K ' , (; F ... more Survival at French Frigate Shoals, Hawaii KF.NNF. 1'11 K. N I E : I ' i I~\ h i h l E K ' , (; F .~K (: F. ti. l i~\ t .~u s 2. (; I. \ , N N I S 1.. N.,\ti..\il ANI) IILIANE K. M<:DEKMONI)' 11. S. Fish and M'ildlife Sei-vice 1 ' 0 Box 50167. Horiolulu. HI Yti850 'National Marine Fisheries Service. Southwest Fisheries Scieiic e (k i t e r , 2570 1)ole St.. HOIIOIIIIU. Hawaii 96XTL-2:KMi Abstract.-Frib.atebirds are known predators 01. sea turtle hatchlings at sevrral locations worldwide. At certain localities this predation might excerbate the already endangered status of these marine reptiles. French Frigate Shoals, Hawaii is where over 90% of all Hawaiian green turtle (Chelm~za my&) breeding occurs and is the site of a large Great Frigatebird (Fregala minor) colony. Frigatebird predation was not a factor in hatchling survival at this location. We found no evidence of green turtle hatchlings in the stomach contents of 200 Great Frigatebirds sampled during peak periods of hatchling
Restoration Ecology, 2016
The restoration of the Nisqually River Delta (Washington, U.S.A.) represents one of the largest e... more The restoration of the Nisqually River Delta (Washington, U.S.A.) represents one of the largest efforts toward reestablishing the ecosystem function and resilience of modified habitat in the Puget Sound, particularly for anadromous salmonid species. The opportunity for outmigrating salmon to access and benefit from the expansion of available tidal habitat can be quantified by several physical attributes, which are related to the ecological and physiological responses of juvenile salmon. We monitored a variety of physical parameters to measure changes in opportunity potential from historic, pre-restoration, and post-restoration habitat conditions at several sites across the delta. These parameters included channel morphology, water quality, tidal elevation, and landscape connectivity. We conducted fish catch surveys across the delta to determine if salmon was utilizing restored estuary habitat. Overall major channel area increased 42% and major channel length increased 131% from pre-to post-restoration conditions. Furthermore, the results of our tidal inundation model indicated that major channels were accessible up to 75% of the time, as opposed to 30% pre-restoration. Outmigrating salmon utilized this newly accessible habitat as quickly as 1 year post-restoration. The presence of salmon in restored tidal channels confirmed rapid post-restoration increases in opportunity potential on the delta despite habitat quality differences between restored and reference sites.
Transactions of the American Fisheries Society
In the context of delta restoration and its impact on salmonid rearing, success is best evaluated... more In the context of delta restoration and its impact on salmonid rearing, success is best evaluated based on whether out-migrating juvenile salmon can access and benefit from suitable estuarine habitat. Here, we integrated 3 years of post-restoration monitoring data including habitat availability, invertebrate prey biomass, and juvenile Chinook salmon (Oncorhynchus tshawytscha) physiological condition to determine whether individuals profited from the addition of 364 ha of delta habitat in South Puget Sound, Washington, United States. Productivity in the restored mudflat was comparable to reference sites 3 years after dike removal, surpassing a mean total of 6 million kJ energy from invertebrate prey. This resulted from the development of a complex network of tidal channels and a resurgence in dipteran biomass that was unique to the restoration area. Consequently, a notable shift in invertebrate consumption occurred between 2010 and 2011, whereby individuals switched from eating primarily amphipods to dipteran flies; however, dietary similarity to the surrounding habitat did not change from year to year, suggesting that this shift was a result of a change in the surrounding prey communities. Growth rates did not differ between restored and reference sites, but catch weight was positively correlated with prey biomass, where greater prey productivity appeared to offset potential density-dependent effects. These results demonstrate how the realized function of restoring estuarine habitat is functionally dependent. High prey productivity in areas with greater connectivity may support healthy juvenile salmon that are more likely to reach the critical size class for offshore survival.
Estuaries provide crucial foraging resources and nursery habitat for threatened populations of an... more Estuaries provide crucial foraging resources and nursery habitat for threatened populations of anadromous salmon. As such, there has been a global undertaking to restore habitat and tidal processes in modified estuaries. The foraging capacity of these ecosystems to support various species of out-migrating juvenile salmon can be quantified by monitoring benthic, terrestrial, and pelagic invertebrate prey communities. Here, we present notable trends in the availability of invertebrate prey at several sites within a restoring large river delta in Puget Sound, Washington, U.S.A. Three years after the system was returned to tidal influence, we observed substantial additions to amphipod, copepod, and cumacean abundances in newly accessible marsh channels (from 0 to roughly 5,000–75,000 individuals/m 2). In the restoration area, terrestrial invertebrate colonization was dependent upon vegetative cover, with dipteran and hymenopteran biomass increasing 3-fold between 1 and 3 years post-restoration. While the overall biodiversity within the restoration area was lower than in the reference marsh, estimated biomass was comparable to or greater than that found within the other study sites. This additional prey biomass likely provided foraging benefits for juvenile Chinook, chum, and coho salmon. Primary physical drivers differed for benthic, terrestrial, and pelagic invertebrates, and these invertebrate communities are expected to respond differentially depending on organic matter exchange and vegetative colonization. Restoring estuaries may take decades to meet certain success criteria, but our study demonstrates rapid enhancements in foraging resources understood to be used for estuary-dependent wildlife.