USGS Science⌕ Search
Home/Archive/USGS

USGS · 70034013

Population synchrony of a native fish across three Laurentian Great Lakes: Evaluating the effects of dispersal and climate

D.B. Bunnell·J.V. Adams·O. T. Gorman·C.P. Madenjian·S.C. Riley·E.F. Roseman·J.S. Schaeffer
View original source ↗Export metadata ↓

Abstract

Climate and dispersal are the two most commonly cited mechanisms to explain spatial synchrony among time series of animal populations, and climate is typically most important for fishes. Using data from 1978-2006, we quantified the spatial synchrony in recruitment and population catch-per-unit-effort (CPUE) for bloater (Coregonus hoyi) populations across lakes Superior, Michigan, and Huron. In this natural field experiment, climate was highly synchronous across lakes but the likelihood of dispersal between lakes differed. When data from all lakes were pooled, modified correlograms revealed spatial synchrony to occur up to 800 km for long-term (data not detrended) trends and up to 600 km for short-term (data detrended by the annual rate of change) trends. This large spatial synchrony more than doubles the scale previously observed in freshwater fish populations, and exceeds the scale found in most marine or estuarine populations. When analyzing the data separately for within- and between-lake pairs, spatial synchrony was always observed within lakes, up to 400 or 600 km. Conversely, between-lake synchrony did not occur among short-term trends, and for long-term trends, the scale of synchrony was highly variable. For recruit CPUE, synchrony occurred up to 600 km between both lakes Michigan and Huron (where dispersal was most likely) and lakes Michigan and Superior (where dispersal was least likely), but failed to occur between lakes Huron and Superior (where dispersal likelihood was intermediate). When considering the scale of putative bloater dispersal and genetic information from previous studies, we concluded that dispersal was likely underlying within-lake synchrony but climate was more likely underlying between-lake synchrony. The broad scale of synchrony in Great Lakes bloater populations increases their probability of extirpation, a timely message for fishery managers given current low levels of bloater abundance. ?? Springer-Verlag 2009.

Explore related subjects

OecologiaArticle

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

D.B. Bunnell, J.V. Adams, O. T. Gorman, C.P. Madenjian, S.C. Riley, E.F. Roseman, J.S. Schaeffer. 2009-11-04. Population synchrony of a native fish across three Laurentian Great Lakes: Evaluating the effects of dispersal and climate. https://doi.org/10.1007/s00442-009-1487-6

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Carryover effects across juvenile periods vary by species, cause-specific mortality, and stage-specific behavior

Conditions during one life-stage can carry over to influence fitness outcomes in later stages. How carryover effects manifest, however, may vary depending on the type and magnitude of risks that animals face in subsequent life-stages. The influence of carryover effects on cause-specific mortality remains largely unclear, particularly during vulnerable life-stages, including juvenile periods. We proposed and investigated the Cause-specific carryover hypothesis, that the relative influence of traits developed during a previous stage on mortality during the next vary by cause of mortality, using juvenile sagebrush songbirds (Brewer’s sparrow, Spizella breweri ; sagebrush sparrow, Artemisiospiza nevadensis ; sage thrasher, Oreoscoptes montanus ) as a focal system. We tracked birds during the post-fledging period (a juvenile period following the nestling period), identified the rates and causes of mortality, and tested the relative influence of different nestling traits (wing length, tarsus length, feather development, and body condition) on post-fledging mortality risk. Carryover effects varied across co-occurring species and differed by cause of mortality, and tarsus length had an unexpected and outsized impact on predation risk in the two sparrows. Although wing morphology typically is considered the most important trait for mobility in birds, most mortalities occurred during the first 5 days of the post-fledging period when altricial fledglings were incapable of flight and likely relied on running or scrambling ability to escape predators. Therefore, carryover effects were driven by stage-specific behavior during the period of highest risk. Developing animals may face investment trade-offs between morphological traits that influence different types of risk during different subsequent stages.

Wyoming↗
USGS2026

The functional effects of African lions on co-occurring carnivores differ across species pairs and with changes in resource availability and lion abundance

Apex carnivores are known to regulate ecosystem structure and function, including via interactions with syntopic, competitively inferior carnivores. These effects may be dependent on relative carnivore density and resource availability or productivity. We investigated the functional effect of African lions as an apex carnivore on the presence of co-occurring large carnivore species across two adjoining National Parks that contrast in relative densities of carnivores and prey. We employed two-species occupancy models from track data to test statistical interactions between lions and the other syntopic large carnivore species, while accounting for each species’ habitat selection. We further investigated the influence of anthropogenic and natural variables on these co-occurrence dynamics. Our models revealed that the occurrence of each carnivore species was best predicted by access to their own key resources. We also found significant statistical interactions between lions and cheetahs, lions and leopards, and lions and spotted hyenas in resource-rich landscapes. Finally, we found limited support for the competition exclusion hypothesis between most species, with the exception of lion-African wild dog co-occurrence patterns. Species’ co-occurrence dynamics were all influenced by resource availability, with lion-leopard and lion-cheetah co-occurrence decreasing strongly with increasing resource availability. Most species co-occurrence declined with increasing occurrence of lions. The patterns revealed by this study improves predictions of how changes in resource availability and carnivore occurrence could impact carnivore community dynamics and the functional role of apex carnivores.

Kruger National Park, Limpopo National Park↗
USGS2025

The effects of carnivory and herbivory on the energy balance of Arctic grizzly bears

Omnivores often face tradeoffs between selecting for spatially dispersed energy-dense vertebrate prey versus densely distributed herbivorous resources that have limited energetic value per unit intake. Arctic grizzly bears ( Ursus arctos ) are large omnivores within a resource-limited ecosystem that are known to exhibit smaller body masses and occur at lower densities than grizzly bears in other regions of North America. We evaluated the energy balance of Arctic grizzly bears during a portion of the fall hyperphagic period in two ecologically differing regions on Alaska’s northern Arctic coast by monitoring mass change, food intake, activity, and energy expenditure of 12 individuals over 17–22 days. Bears in coastal areas were more carnivorous than bears in the foothills that were predominantly herbivorous and frugivorous. Carnivory was associated with greater movement, body fat, and energy expenditure and two of four carnivorous bears lost mass. Overall, the mean body fat of the bears in this study was 34% lower than other grizzly bear populations in North America in the fall. Furthermore, the bears in this study exhibited relatively small changes in body mass (x̄ = 3%, range =−2 to 11%) that were 60% lower than other grizzly bear populations which typically gain substantial mass in the fall in preparation for denning. Our results, while representing a snapshot from a small number of bears during the fall hyperphagic period, are consistent with previous studies and indicate limited availability of energy-dense food resources during this time for grizzly bears in this region of the Arctic.

Alaska↗