scholarly journals Changes In Argentine Ant Trophic Position As A Function of Time

2021 ◽  
Author(s):  
Evelyne Baratelli ◽  
Chad Tillberg ◽  
Andy Suarez ◽  
Sean Menke ◽  
Ida Naughton ◽  
...  
Keyword(s):  
Trophic Position ◽  
Isotope Analysis ◽  
Leading Edge ◽  
River Valley ◽  
Argentine Ant ◽  
Sacramento River ◽  
Ecological Processes ◽  
San Nicolas Island ◽  
Temporal Sampling ◽  
Over Time

Abstract The ecological effects of species introductions can change over time, but an understanding of how and why they do remains hindered by the lack of long-term data sets that permit investigation into underlying causes. We employed stable isotope analysis to estimate how trophic position changes as a function of time for the Argentine Ant, a widespread, abundant, and ecologically disruptive introduced species. Previous research at a site in southern California (Rice Canyon, San Diego Co.) found that Argentine Ant δ15N values were higher at the leading edge of invasion than at those same sites in years subsequent to invasion. To assess if a reduction in relative trophic position over time is a typical feature of ant invasions, we expanded the temporal and spatial scale of sampling and measured δ15N values of the Argentine ant at three locations with a known or inferred history of invasion: Rice Canyon (the site of the original study), the Sacramento River Valley (Yolo and Solano Cos., CA), and San Nicolas Island (Ventura Co., CA). Resampling Rice Canyon in 2019, 16 years after the original survey, revealed a significant increase in Argentine ant δ15N values. At the two other locations, Argentine ant δ15N values were independent of time since invasion (Sacramento River Valley) or position relative to the invasion front (San Nicolas Island). These findings suggest that post-invasion reductions in trophic position may not be a general phenomenon or could reflect transitory ecological processes that require finer-scale temporal sampling than was possible to achieve in the present study. Our findings are nonetheless consistent with the results of recent studies, which found that the effects of Argentine ant invasions persist over decadal time scales.

Investigating the diet of the omnivorous mirid Dicyphus hesperus using stable isotopes

2009 ◽  
Vol 99 (4) ◽  
pp. 347-358 ◽  
Author(s):  
J.A. Bennett ◽  
D.R. Gillespie ◽  
S.L. VanLaerhoven
Keyword(s):  
Nitrogen Isotopes ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Isotopic Signature ◽  
Encarsia Formosa ◽  
Verbascum Thapsus ◽  
Diet Variability ◽  
Feeding Trials ◽  
Plant Sources ◽  
Over Time

AbstractOmnivory involves numerous feeding relationships and a complex web of interactions. When using omnivores in biocontrol, these interactions need to be understood to maximize feeding on the target species and minimize non-target interactions. Dicyphus hesperus is used along with Encarsia formosa for biocontrol of whiteflies in greenhouse tomato crops. Dicyphus hesperus is a generalist omnivore which feeds on all components of the system. To quantify these interactions, stable isotope analysis was used to identify trophic position with nitrogen isotopes (δ15N) and plant sources with carbon isotopes (δ13C). Feeding trials were used to establish baseline isotopic data for D. hesperus and their diet, including Verbascum thapsus, an alternative plant food. Cage trials were used to monitor population abundances and the isotopic signature of D. hesperus. In feeding trials, D. hesperus were enriched relative to their food, suggesting an elevated trophic position. However, large amounts of isotopic variation were found within all diet components, with only V. thapsus exhibiting a distinct signature. In cage trials, the average δ15N and δ13C of the omnivore declined over time, coinciding with declines in total available prey, though it may be confounded by changes in temperature. The range of δ13C, but not the range of δ15N, also declined over time. This suggests a change in the plant source within the diet, but also some unquantified variability within the population. We suggest that diet variability exists within D. hesperus populations, declining as prey become less abundant.

scholarly journals Connecting laboratory behavior to field function through stable isotope analysis

2016 ◽  
Author(s):  
Mael G Glon ◽  
Eric R Larson ◽  
Kevin L Pangle
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Laboratory Experiments ◽  
Trophic Position ◽  
Scale Up ◽  
Isotope Analysis ◽  
Natural Conditions ◽  
Behavioral Experiments ◽  
Ecological Processes ◽  
Field Function

Inherent difficulties of tracking and observing organisms in the field often leave researchers with no choice but to conduct behavioral experiments under laboratory settings. However, results of laboratory experiments do not always translate accurately to natural conditions. A fundamental challenge in ecology is therefore to scale up from small area and short-duration laboratory experiments to large areas and long-durations over which ecological processes generally operate. In this study, we propose that stable isotope analysis may be a tool that can link laboratory behavioral observations to past field interactions or function of individual organisms. We conducted laboratory behavioral assays to measure dominance of invasive rusty crayfish, Orconectes rusticus, and used stable isotope analysis to hindcast trophic positions of these crayfish under preceding natural conditions. We hypothesized that more dominant crayfish in our assays would have higher trophic positions if dominance were related to competitive ability or willingness to pursue high-risk, high-reward prey. We did not find a relationship between crayfish dominance and trophic position, and therefore infer that laboratory dominance of crayfish may not necessarily relate to their ecology in the field. However, this is to our knowledge the first attempt to directly relate laboratory behavior to field performance via stable isotope analysis. We encourage future studies to continue to explore a possible link between laboratory and field behavior via stable isotope analysis, and propose several avenues to do so.

scholarly journals Connecting laboratory behavior to field function through stable isotope analysis

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1918 ◽  
Author(s):  
Mael G. Glon ◽  
Eric R. Larson ◽  
Kevin L. Pangle
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Laboratory Experiments ◽  
Trophic Position ◽  
Scale Up ◽  
Isotope Analysis ◽  
Natural Conditions ◽  
Behavioral Experiments ◽  
Ecological Processes ◽  
Field Function

Inherent difficulties of tracking and observing organisms in the field often leave researchers with no choice but to conduct behavioral experiments under laboratory settings. However, results of laboratory experiments do not always translate accurately to natural conditions. A fundamental challenge in ecology is therefore to scale up from small area and short-duration laboratory experiments to large areas and long durations over which ecological processes generally operate. In this study, we propose that stable isotope analysis may be a tool that can link laboratory behavioral observations to past field interactions or function of individual organisms. We conducted laboratory behavioral assays to measure dominance of invasive rusty crayfish,Orconectes rusticus, and used stable isotope analysis to hindcast trophic positions of these crayfish under preceding natural conditions. We hypothesized that more dominant crayfish in our assays would have higher trophic positions if dominance were related to competitive ability or willingness to pursue high-risk, high-reward prey. We did not find a relationship between crayfish dominance and trophic position, and therefore infer that laboratory dominance of crayfish may not necessarily relate to their ecology in the field. However, this is to our knowledge the first attempt to directly relate laboratory behavior to field performance via stable isotope analysis. We encourage future studies to continue to explore a possible link between laboratory and field behavior via stable isotope analysis, and propose several avenues to do so.

scholarly journals A review of methods used to analyse albatross diets—assessing priorities across their range

2016 ◽  
Vol 73 (9) ◽  
pp. 2125-2137 ◽  
Author(s):  
Julie C. McInnes ◽  
Ben Raymond ◽  
Richard A. Phillips ◽  
Simon N. Jarman ◽  
Mary-Anne Lea ◽  
...  
Keyword(s):  
Gap Analysis ◽  
Isotope Analysis ◽  
Breeding Site ◽  
Conservation Priorities ◽  
Morphological Examination ◽  
Management Options ◽  
Temporal Sampling ◽  
Dietary Flexibility ◽  
Morphological Studies ◽  
Over Time

Abstract Many seabird populations are threatened by interactions with commercial fisheries, and climate change. Understanding their prey requirements and dietary flexibility in this context is important for effective conservation and management. However, changes in the methods used to assess diet, as well as the spatial and temporal coverage of monitoring schemes, may reduce our ability to detect and monitor these marine threats. To help assess conservation priorities linked to diet, we performed a systematic review of 109 albatross diet papers published between 1950 and 2016, which corresponded to 296 studies when stratified by sampling year, breeding site, and breeding species. We assessed the methods used, changes over time, and spatial and temporal sampling coverage by species and island group. Most albatross studies have focused on chick-rearing, and diet during other breeding phases is comparatively poorly known. Furthermore, chicks are more commonly sampled than adults and very rarely immature birds, all of which may differ in diet composition. There was a pronounced shift over time in the preferred method of characterising diet, from the morphological examination of prey remains to stable isotope analysis of tissue. This shift has reduced the volume of detailed taxonomic information available from morphological studies. This difference in resolution hinders the ability to detect changes in prey species, with implications for management of threatened albatrosses and for monitoring broader changes in marine ecosystems. In a knowledge gap analysis for important breeding colonies (with >5% of global population), we identified key sites where existing monitoring has provided a foundation for robust longitudinal diet studies. Maintaining and augmenting these long-term research programmes will enable analyses of the impacts of changing climate and fishing practices on seabird populations and facilitate the timely identification and implementation of management options.

scholarly journals Connecting laboratory behavior to field function through stable isotope analysis

2016 ◽  
Author(s):  
Mael G Glon ◽  
Eric R Larson ◽  
Kevin L Pangle
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Laboratory Experiments ◽  
Trophic Position ◽  
Scale Up ◽  
Isotope Analysis ◽  
Natural Conditions ◽  
Behavioral Experiments ◽  
Ecological Processes ◽  
Field Function

Inherent difficulties of tracking and observing organisms in the field often leave researchers with no choice but to conduct behavioral experiments under laboratory settings. However, results of laboratory experiments do not always translate accurately to natural conditions. A fundamental challenge in ecology is therefore to scale up from small area and short-duration laboratory experiments to large areas and long-durations over which ecological processes generally operate. In this study, we propose that stable isotope analysis may be a tool that can link laboratory behavioral observations to past field interactions or function of individual organisms. We conducted laboratory behavioral assays to measure dominance of invasive rusty crayfish, Orconectes rusticus, and used stable isotope analysis to hindcast trophic positions of these crayfish under preceding natural conditions. We hypothesized that more dominant crayfish in our assays would have higher trophic positions if dominance were related to competitive ability or willingness to pursue high-risk, high-reward prey. We did not find a relationship between crayfish dominance and trophic position, and therefore infer that laboratory dominance of crayfish may not necessarily relate to their ecology in the field. However, this is to our knowledge the first attempt to directly relate laboratory behavior to field performance via stable isotope analysis. We encourage future studies to continue to explore a possible link between laboratory and field behavior via stable isotope analysis, and propose several avenues to do so.

scholarly journals Gut microbiome is affected by inter-sexual and inter-seasonal variation in diet for thick-billed murres (Uria lomvia)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Esteban Góngora ◽  
Kyle H. Elliott ◽  
Lyle Whyte
Keyword(s):  
Gut Microbiome ◽  
Sulfur Isotopes ◽  
Trophic Position ◽  
Isotope Analysis ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Uria Lomvia ◽  
Fecal Microbiome ◽  
Prey Specialization ◽  
Rrna Gene Sequencing

AbstractThe role of the gut microbiome is increasingly being recognized by health scientists and veterinarians, yet its role in wild animals remains understudied. Variations in the gut microbiome could be the result of differential diets among individuals, such as variation between sexes, across seasons, or across reproductive stages. We evaluated the hypothesis that diet alters the avian gut microbiome using stable isotope analysis (SIA) and 16S rRNA gene sequencing. We present the first description of the thick-billed murre (Uria lomvia) fecal microbiome. The murre microbiome was dominated by bacteria from the genus Catellicoccus, ubiquitous in the guts of many seabirds. Microbiome variation was explained by murre diet in terms of proportion of littoral carbon, trophic position, and sulfur isotopes, especially for the classes Actinobacteria, Bacilli, Bacteroidia, Clostridia, Alphaproteobacteria, and Gammaproteobacteria. We also observed differences in the abundance of bacterial genera such as Catellicoccus and Cetobacterium between sexes and reproductive stages. These results are in accordance with behavioural observations of changes in diet between sexes and across the reproductive season. We concluded that the observed variation in the gut microbiome may be caused by individual prey specialization and may also be reinforced by sexual and reproductive stage differences in diet.

Landscape Heterogeneity and Dynamics

2019 ◽  
pp. 42-126
Author(s):  
Kimberly A. With
Keyword(s):  
Landscape Ecology ◽  
Spatial Heterogeneity ◽  
Landscape Structure ◽  
Landscape Heterogeneity ◽  
Spatial Scales ◽  
Anthropogenic Disturbances ◽  
Ecological Processes ◽  
Disturbance Dynamics ◽  
Wide Range ◽  
Over Time

Heterogeneity is a defining characteristic of landscapes and therefore central to the study of landscape ecology. Landscape ecology investigates what factors give rise to heterogeneity, how that heterogeneity is maintained or altered by natural and anthropogenic disturbances, and how heterogeneity ultimately influences ecological processes and flows across the landscape. Because heterogeneity is expressed across a wide range of spatial scales, the landscape perspective can be applied to address these sorts of questions at any level of ecological organization, and in aquatic and marine systems as well as terrestrial ones. Disturbances—both natural and anthropogenic—are a ubiquitous feature of any landscape, contributing to its structure and dynamics. Although the focus in landscape ecology is typically on spatial heterogeneity, disturbance dynamics produce changes in landscape structure over time as well as in space. Heterogeneity and disturbance dynamics are thus inextricably linked and are therefore covered together in this chapter.

Trophic ecology of the chihuil sea catfish (Bagre panamensis) in the south-east Gulf of California, México

2017 ◽  
Vol 98 (4) ◽  
pp. 885-893 ◽  
Author(s):  
Víctor M. Muro-Torres ◽  
Felipe Amezcua ◽  
Raul E. Lara-Mendoza ◽  
John T. Buszkiewicz ◽  
Felipe Amezcua-Linares
Keyword(s):  
Gulf Of California ◽  
Trophic Ecology ◽  
Trophic Position ◽  
Feeding Habits ◽  
Isotope Analysis ◽  
Demersal Fish ◽  
Trophic Levels ◽  
High Plasticity ◽  
Combined Use ◽  
Ecosystem Based Fisheries Management

The trophic ecology of the chihuil sea catfish Bagre panamensis was studied through high-resolution variations in its feeding habits and trophic position (TP) in the SE Gulf of California, relevant to sex, size and season. The combined use of stomach content (SCA) and stable isotope analysis (SIA) allowed us to perform these analyses and also estimate the TP of its preys. Results of this study show that the chihuil sea catfish is a generalist and opportunistic omnivore predator that consumes primarily demersal fish and peneid shrimps. Its diet did not vary with climatic season (rainy or dry), size or sex. Results from the SIA indicated high plasticity in habitat use and prey species. The estimated TP value was 4.19, which indicates a tertiary consumer from the soft bottom demersal community in the SE Gulf of California, preying on lower trophic levels, which aids in understanding the species' trophic role in the food web. Because this species and its prey are important to artisanal and industrial fisheries in the Gulf of California, diet assimilation information is useful for the potential establishment of an ecosystem-based fisheries management in the area.

Trophic relationships of breeding Red-necked Grebes (Podiceps grisegena) on wetlands with and without fish in the Aspen Parkland

2010 ◽  
Vol 88 (2) ◽  
pp. 186-194 ◽  
Author(s):  
C. E. McParland ◽  
C. A. Paszkowski ◽  
J. L. Newbrey
Keyword(s):  
Egg Production ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Trophic Levels ◽  
Trophic Relationships ◽  
Breeding Sites ◽  
Top Predators ◽  
Aspen Parkland ◽  
Wintering Areas ◽  
Podiceps Grisegena

Dietary overlap between waterbirds and fish in many freshwater systems can lead to competition for food resources and changes in the trophic position of top predators. We used stable isotope analysis of carbon and nitrogen from egg tissues to document differences in the trophic position of breeding Red-necked Grebes ( Podiceps grisegena (Boddaert, 1783)) on wetlands with and without fish in the Aspen Parkland of Alberta, Canada. Grebes occupied higher trophic levels in the presence of fish than in their absence, suggesting that small-bodied fish in Aspen Parkland food webs may lengthen food chains in which grebes are top predators. A mixed diet of invertebrates and fishes may be adaptive for grebes in this highly variable ecosystem where fish colonize wetlands in wet years and are extirpated in dry years. Carbon analyses indicated that female grebes likely obtained resources for egg production from breeding sites and not from wintering areas, as eggs had similar δ13C values to wetland primary producers, invertebrates, and fishes.

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