Assessing the Breeding Success of the Western Grebe (<i>Aechmophorus occidentalis</i>) After 40 Years of Environmental Changes at Delta Marsh, Manitoba

Porte, Nicholas La; Koper, Nicola; Leston, Lionel

doi:10.1675/063.037.0106

Cited by 10 publications

(4 citation statements)

References 39 publications

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“…Thus, both 0C (Hunter et al, 2011) and 1C carp (Kloskowski, 2011c) were found to prey on tadpoles, even though it remains to be evaluated to what extent this could also have been an artifact of holding carp within a confined space (especially tanks, as in the former experiment). On the other hand, the destruction of nests of the western grebe (Aechmophorus occidentalis, Podicipedidae) in vegetated areas of a marsh as a result of spawning activities (La Porte et al, 2014) and the direct predation upon the eggs of white sturgeon (Acipenser transmontanus, Acipenseridae) (Miller and Beckman, 1996) were direct effects of carp both documented under natural conditions.…”

Section: The Conceptual Model Revisitedmentioning

confidence: 99%

Experimental Evidence from Causal Criteria Analysis for the Effects of Common CarpCyprinus carpioon Freshwater Ecosystems: A Global Perspective

Vilizzi

Tarkan

Copp

2015

Reviews in Fisheries Science & Aquaculture

127

132

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As the most widely distributed freshwater fish worldwide, common carp Cyprinus carpio can be either invasive or "naturalized" in most areas of introduction. This leads to different levels of perception regarding the species' role in freshwater ecosystems, with experimental research focusing either on its "middle-out" impacts or overall function in limnological processes. At the same time, the large scales at which carp dynamics operate may severely limit the validity of laboratory and, oftentimes, field experiments in extrapolating results to real-world ecosystems. In this study, 129 laboratory, field, and "natural" experiments were systematically reviewed through causal criteria analysis, and within an historical/biogeographical and risk-assessment context. Of the 19 countries where experiments were conducted, only 4 were considered as "low risk" and one as "no risk, " the other being "medium" to "high risk. " Experimental findings from 373 component-wise assessments supported the framework of effects on water quality, vegetation, invertebrates, and vertebrates, with the latter including also amphibians and waterfowl, previously unreported. Stronger evidence was provided by natural and field relative to laboratory experiments, reflecting the reductionism of the latter. Critical biomass for an impact was highly dependent on experimental setup, even though the overall threshold of %200 kg ha ¡1 under natural conditions supported recent findings. Management of carp should reflect the level of current and potential risk posed by the species in its different areas of distribution, thereby accounting for projections of further spread but also for unsuccessful colonization. Future experimentation should favor a holistic!reductionist over a reductionist!holistic approach.

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Section: The Conceptual Model Revisitedmentioning

confidence: 99%

Experimental Evidence from Causal Criteria Analysis for the Effects of Common CarpCyprinus carpioon Freshwater Ecosystems: A Global Perspective

Vilizzi

Tarkan

Copp

2015

Reviews in Fisheries Science & Aquaculture

127

132

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“…The introduction of new species of fishes has dramatically altered the trophic relationships of Clear Lake (Thomson et al 2013). The introduced Common Carp vigorously thrashes at the surface during spawning, and such activity is considered the second highest cause of nest failure in Western Grebes at a marsh in Manitoba, Canada (LaPorte et al 2014); however, we documented only one such incident on Clear Lake with a motion-activated camera. Feerer and Garrett (1977) suggested that the introduction in 1967 of the Mississippi Silverside, which quickly became the most abundant species of fish in the lake (Cook 1981), contributed to the decline of nesting grebes by competing with the grebes' preferred prey fish.…”

Section: Anthropogenic Causes Of Nest Failurementioning

confidence: 87%

“…Because many species of vertebrates exploit the nests of grebes for egg dumping, predation, scavenging, resting, and foraging (Hayes et al 2018a), incidental destruction of eggs likely occurs more frequently than our limited data suggest. Destruction of nests by the Common Carp was considered the second highest cause of nest failure in Western Grebes at a marsh in Manitoba, Canada, but that result was limited to a single colony during a single year (LaPorte et al 2014). Elsewhere we reported the use of grebe nests at Clear Lake by 47 species of vertebrates (Hayes et al 2018a).…”

Section: Natural Causes Of Nest Failurementioning

confidence: 99%

Historical and Recent Breeding of the Western Grebe and Clark's Grebe in a Severely Impaired Ecosystem at Clear Lake, California

Hayes

McIntosh²,

Turner

et al. 2022

Monographs of the Western North American Naturalist

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Clear Lake is a large (176.7-km 2 ) natural lake in northern California, USA. An estimated 1000 pairs of Western Grebes (Aechmophorus occidentalis) and Clark's Grebes (A. clarkii) nested on the lake prior to massive applications of the pesticide dichlorodiphenyldichloroethane (DDD) to kill the Clear Lake gnat (Chaoborus astictopus) during 1949-1957. Biomagnification of DDD was implicated as the cause of several mass mortality events of grebes and short-term reproductive failure in the 1950s, although other factors such as mercury (Hg) poisoning may have contributed. Successful nesting resumed in 1960 and increased gradually, with up to 165 nests in 1967 but fewer through 1976. Subsequent surveys revealed up to 390 nests annually during 1992-1995 and up to 2675 nests annually during 1996-2010. We conducted 7-29 nest surveys annually during 2010-2019 and found a mean of 3123 nests per year. The annual number of nests varied dramatically (range 898 to 5936) and was unrelated to water level. The grebes nested at 28 sites in Clear Lake and 9 sites in associated wetlands, with proportionately more nests on Clear Lake and fewer nests in adjacent wetlands during years with low water level. Western Grebes attended 84.9% of the nests and Clark's Grebes attended 15.1%. During years with low water, there were proportionately more open water nests, which were anchored to submergent vegetation farther from shore and in deeper water than marsh nests, which were more densely placed in emergent vegetation closer to shore in shallower water. Brood surveys along the perimeter of the lake at the end of each breeding season revealed considerable variation in the number of young (1-599, x -= 153.9), young per nest (0.00025-0.118, x -= 0.04), and productivity ratio of young to adults (0.0006-0.252, x -= 0.07). Reproductive success was unrelated to water level. Wind-generated waves were a major cause of nest failure, destroying up to 35% of a year's nests. Predation on eggs was also a major cause of nest failure. American Crow (Corvus brachyrhynchos) was the dominant predator during the day (84% of predation events), and northern raccoon (Procyon lotor) was the dominant predator at night (98% of predation events). Nocturnal predation by mammals occurred most frequently when water level was high because nests were placed closer to shore and were more accessible. The grebes' breeding population has recovered since DDD biomagnification during the 1950s and may be larger due to 2 introduced fish species competing for plankton with benthic larvae of the Clear Lake gnat, which previously transferred large quantities of biomass from aquatic to terrestrial ecosystems during emergence. However, the grebes' reproductive success remains lower at Clear Lake than at several other breeding localities. The bioaccumulation and biomagnification of toxic chemicals and the periodic reductions of prey fish from hypoxic areas of the lake during periods of intense cyanobacterial and algal blooms may reduce reproductive success.

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“…The body weight and beak length from the tip of the upper mandible to the end of the culmen were used to sex birds. 17,18 Sex was verified on postmortem examination or through DNA extracted from a blood sample (Zoogen Services, Davis, CA, USA). Postmortem examination was performed on birds belonging to a subset that had surgical implantation of coelomic radio transmitters that died before release.…”

Section: Animals and Samplingmentioning

confidence: 99%

Effects of Season, Location, Species, and Sex on Hematologic and Plasma Biochemical Values and Body Mass in Free-ranging Grebes (Aechmophorus species)

Anderson¹,

Cruz

Gaydos³

et al. 2021

Journal of Avian Medicine and Surgery

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Assessing the Breeding Success of the Western Grebe (Aechmophorus occidentalis) After 40 Years of Environmental Changes at Delta Marsh, Manitoba

Cited by 10 publications

References 39 publications

Experimental Evidence from Causal Criteria Analysis for the Effects of Common CarpCyprinus carpioon Freshwater Ecosystems: A Global Perspective

Experimental Evidence from Causal Criteria Analysis for the Effects of Common CarpCyprinus carpioon Freshwater Ecosystems: A Global Perspective

Historical and Recent Breeding of the Western Grebe and Clark's Grebe in a Severely Impaired Ecosystem at Clear Lake, California

Effects of Season, Location, Species, and Sex on Hematologic and Plasma Biochemical Values and Body Mass in Free-ranging Grebes (Aechmophorus species)

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