Inter-colony foraging dynamics and breeding success relate to prey availability in a pursuit-diving seabird

2020 ◽  
Vol 651 ◽  
pp. 183-198
Author(s):  
J Gulka ◽  
E Jenkins ◽  
LD Maynard ◽  
WA Montevecchi ◽  
PM Regular ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Prey Availability ◽  
Anthropogenic Pressures ◽  
Niche Dynamics ◽  
Common Murres ◽  
Distribution Of Resources ◽  
Foraging Niche ◽  
And Behavior ◽  
Foraging Distances ◽  
Adult Diet

Spatial patterns of breeding seabirds are influenced by the distribution of resources in relation to the colony and the density of conspecifics from the same or adjacent colonies. We conducted an inter-colony comparison of foraging space use and behavior, diet, and reproductive success of common murres Uria aalge breeding at a large offshore and a small inshore colony on the northeastern coast of Newfoundland (Canada) during 2016-2018 under varying prey (capelin Mallotus villosus) biomass. Murres from the large offshore colony foraged over a greater area, with greater individual foraging distances, indicative of higher commuting costs compared to the smaller inshore colony. Although this pattern might reflect prey depletion near the offshore colony due to higher conspecific densities, it likely also reflects the greater distance to predictable, high-abundance prey aggregations. This is supported by high spatial overlap of foraging areas from both colonies near coastal, annually persistent capelin spawning sites. Adult diet was similar between colonies during incubation, but diverged during chick-rearing, with offshore murres consuming a higher proportion of alternative prey, while inshore murres consumed more capelin. These differences did not affect fledging success, although hatching success was lower in the larger colony, suggesting that divergent factors (e.g. predation, nest attendance) influence colony-specific population dynamics. Overall, our findings suggest that abundant local prey is key in shaping spatial patterns of breeding common murres in northeastern Newfoundland and results in apparently minimal intraspecific competition. As anthropogenic pressures on resource availability heighten, insight into factors influencing intraspecific foraging niche dynamics will be critical to inform management.

Evolution and Political Decision Making

2020 ◽  
Author(s):  
Anthony C. Lopez
Keyword(s):  
Decision Making ◽  
Political Violence ◽  
Psychological Consequences ◽  
Political Decision ◽  
Ecological Problems ◽  
Distribution Of Resources ◽  
The Many ◽  
Scientific Truth ◽  
And Behavior ◽  
Political Decision Making

The application of evolutionary theories or models to explain political decision making is quickly maturing, fundamentally interdisciplinary, and irreducibly complex. This hybridization has yielded significant benefits, including real progress toward understanding the conditions under which cooperation is possible, and a clearer understanding of the apparently “irrational” drivers of political violence. Decision making requires a nervous system that conditions motivation and behavior upon adaptively relevant cues in the environment. Such systems do not exist because they maximize utility, enlightenment, or scientific truth; they exist because on average they led to outcomes that were reproductively beneficial in ancestral environments. The reproductive challenges faced by our ancestors included not only ecological problems of predator avoidance but also political problems such as inter-group threat and the distribution of resources within groups. Therefore, evolutionary approaches to political decision making require direct and deep engagement of the logic whereby natural selection builds adaptations. This view of human psychology yields valuable insights on the domain specificity of political decision making as well as the psychological consequences of mismatch between modern and ancestral environments. In other words, there is accumulating evidence that many of the complex adaptations of the human brain were designed to solve the many problems of ancestral politics. This discussion begins by distinguishing evolutionary approaches from other frameworks used to explain political decision making, such as rational choice, or realism in international relations. Since evolutionary models of political decision making have now produced decades of original theoretical and empirical contributions, we are in a useful position to take stock of this research landscape. Doing so crystalizes the promises, perils, and scope of evolutionary approaches to politics.

Niche dynamics of sympatric non‐breeding shearwaters under varying prey availability

Ibis ◽  
2019 ◽  
Vol 162 (3) ◽  
pp. 701-712 ◽  
Author(s):  
Paloma C. Carvalho ◽  
Gail K. Davoren
Keyword(s):  
Prey Availability ◽  
Niche Dynamics

scholarly journals Spatial patterns of water quality in Xingu River Basin (Amazonia) prior to the Belo Monte dam impoundment

2015 ◽  
Vol 75 (3 suppl 1) ◽  
pp. 34-46 ◽  
Author(s):  
JL. Rodrigues-Filho ◽  
DS. Abe ◽  
P. Gatti-Junior ◽  
GR. Medeiros ◽  
RM. Degani ◽  
...  
Keyword(s):  
Water Quality ◽  
River Basin ◽  
Spatial Patterns ◽  
Amazon Basin ◽  
Environmental Changes ◽  
Anthropogenic Activities ◽  
Data Sampling ◽  
Anthropogenic Pressures ◽  
Xingu River ◽  
Belo Monte

Abstract The Xingu River, one of the most important of the Amazon Basin, is characterized by clear and transparent waters that drain a 509.685 km2 watershed with distinct hydrological and ecological conditions and anthropogenic pressures along its course. As in other basins of the Amazon system, studies in the Xingu are scarce. Furthermore, the eminent construction of the Belo Monte for hydropower production, which will alter the environmental conditions in the basin in its lower middle portion, denotes high importance of studies that generate relevant information that may subsidize a more balanced and equitable development in the Amazon region. Thus, the aim of this study was to analyze the water quality in the Xingu River and its tributaries focusing on spatial patterns by the use of multivariate statistical techniques, identifying which water quality parameters were more important for the environmental changes in the watershed. Data sampling were carried out during two complete hydrological cycles in twenty-five sampling stations. The data of twenty seven variables were analyzed by Spearman's correlation coefficients, cluster analysis (CA), and principal component analysis (PCA). The results showed a high auto-correlation between variables (> 0.7). These variables were removed from multivariate analyzes because they provided redundant information about the environment. The CA resulted in the formation of six clusters, which were clearly observed in the PCA and were characterized by different water quality. The statistical results allowed to identify a high spatial variation in the water quality, which were related to specific features of the environment, different uses, influences of anthropogenic activities and geochemical characteristics of the drained basins. It was also demonstrated that most of the sampling stations in the Xingu River basin showed good water quality, due to the absence of local impacts and high power of depuration of the river itself.

scholarly journals Floral Resources Enhance Fecundity, but Not Flight Activity, in a Specialized Aphid Predator, Hippodamia convergens (Coleoptera: Coccinellidae)

2021 ◽  
Vol 9 ◽  
Author(s):  
Hannah E. Stowe ◽  
J. P. Michaud ◽  
Tania N. Kim
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Prey Availability ◽  
Flight Activity ◽  
Flight Behavior ◽  
Floral Resources ◽  
Adult Survival ◽  
Adult Size ◽  
Hippodamia Convergens ◽  
Adult Diet

Adult aphid predators disperse across the landscape seasonally in search of prey aggregations that are patchily distributed and temporally variable. However, flight is energetically costly and consumes resources that could be invested in reproduction. Hippodamia convergens is an important aphid predator in North American cereal crops and other agricultural systems. Consumption of floral resources can enhance adult survival during periods of low prey availability and may improve reproductive success. We tested how an omnivorous adult diet containing floral resources (diluted honey and pulverized bee pollen) interacts with body size to influence reproduction and flight behavior compared to a prey-only diet. Two sizes of beetles were produced by controlling larval access to food—3 h daily access produced small beetles; ad libitum access produced large beetles with faster development. Reproductive performance was tracked for 18 days, and female flight activity was assayed via 3 h bouts of tethered flight. Diet composition and body size interacted to influence preoviposition period, with large females in prey-only treatments delaying oviposition the longest. The omnivorous adult diet improved 18-day fecundity relative to a prey-only diet, but egg fertility was unaffected. Adult size affected oviposition pattern, with small beetles laying smaller, but more numerous, clutches. Females flew up to 7 km in 6 h, but neither body size nor adult diet influenced flight distance, suggesting that all diet treatments generated energy reserves sufficient to power flights of short duration. However, pre-reproductive females flew > 60% further than they did post-reproduction, likely due to the energetic costs of oviposition. Thus, access to pollen and nectar increased reproductive success and altered oviposition patterns in H. convergens, indicating the importance of floral resources in the agricultural landscape to conservation of this predator and its biological control services.

Seasonal changes in spatial patterns and behavior of yearling male blue grouse on the breeding range

1983 ◽  
Vol 61 (12) ◽  
pp. 2777-2780 ◽  
Author(s):  
Ian G. Jamieson
Keyword(s):  
British Columbia ◽  
Home Range ◽  
Spatial Patterns ◽  
Seasonal Changes ◽  
Late Summer ◽  
Home Ranges ◽  
Breeding Range ◽  
Dendragapus Obscurus ◽  
Radio Transmitters ◽  
And Behavior

Changes in spatial patterns and behavior of yearling male blue grouse (Dendragapus obscurus) equipped with radio transmitters were recorded during spring and summer, 1980 and 1981, on Hardwicke Island, British Columbia. Sizes of home ranges decreased and yearlings appeared to become less dispersed as the season progressed. Most birds moved off their initial home range and onto new areas on the breeding range by late summer although the timing of this movement varied among individuals. Interactions involving yearling males with females and territorial males decreased as the season advanced. Changes in spatial patterns and behavior appear to be related to seasonal changes in levels of hormones in yearling males.

Foraging-Niche Dynamics of Gadwalls and American Coots in Winter

The Auk ◽  
1998 ◽  
Vol 115 (3) ◽  
pp. 670-683 ◽  
Author(s):  
S. Keith McKnight ◽  
Gary R. Hepp
Keyword(s):  
Niche Dynamics ◽  
Foraging Niche

scholarly journals Hortonian Scaling of Coupled Hydrological and Biogeochemical Responses Across an Intensively Managed River Basin

2021 ◽  
Vol 3 ◽  
Author(s):  
Soohyun Yang ◽  
Enrico Bertuzzo ◽  
Dietrich Borchardt ◽  
P. Suresh C. Rao
Keyword(s):  
River Basin ◽  
Analytical Model ◽  
Spatial Patterns ◽  
Large Scale ◽  
Removal Rate ◽  
River Basins ◽  
Nutrient Loads ◽  
Biogeochemical Processes ◽  
Anthropogenic Pressures ◽  
Human Settlements

Structural and functional attributes across fractal river networks have been characterized by well-established and consistent hierarchical, Hortonian scaling patterns. In most of the global river basins, spatial patterns of human settlements also conform to similar hierarchical scaling. However, emergent spatial hierarchical patterns and scaling of heterogeneous anthropogenic nutrient loads over a river basin are less known. As a case study, we examined here a large intensely managed river basin in Germany (Weser River; 46K km2; 8M population). Archived data for point-/diffuse-sources of total Phosphorus (Ptot) input loads were combined with numerical and analytical model simulations of coupled hydrological and biogeochemical processes for in-stream Ptot removal at the network scale. We find that Ptot input loads scale exponentially over stream-orders, with the larger scaling constant for point-source loads from urban agglomerations compared to those for diffuse-source contributions from agricultural and forested areas. These differences in scaling patterns result from hierarchical self-organization of human settlements, and the associated clustering of large-scale, altered land-cover. Fraction of Ptot loads removed through in-stream biogeochemical processes also manifests Hortonian scaling, consistent with predictions of an analytical model. Our analyses show that while smaller streams are more efficient in Ptot removal, in larger streams the magnitude of Ptot loads removed is higher. These trends are consistent with inverse scaling of nutrient removal rate constant with mean discharge, and downstream clustering of larger cumulative input loads. Analyses of six nested sub-basins within the Weser River Basin also reveal similar scaling patterns. Our findings are useful for projecting likely water-quality spatial patterns in similar river basins in Germany, and Central Europe. Extensions and generalizations require further examination of diverse basins with archetype spatial heterogeneities in anthropogenic pressures and hydroclimatic settings.

scholarly journals Meta-Analysis of Salmon Trophic Ecology Reveals Spatial and Interspecies Dynamics Across the North Pacific Ocean

2021 ◽  
Vol 8 ◽  
Author(s):  
Caroline Graham ◽  
Evgeny A. Pakhomov ◽  
Brian P. V. Hunt
Keyword(s):  
Spatial Patterns ◽  
North Pacific ◽  
Large Scale ◽  
Prey Availability ◽  
Gulf Of Alaska ◽  
Marine Ecology ◽  
Niche Width ◽  
Fine Scale ◽  
The North ◽  
The North Pacific

We examined spatial patterns in diet, trophic niche width and niche overlap for chum, pink and sockeye salmon across the North Pacific during 1959–1969. This is a baseline period before major hatchery enhancement occurred coinciding with a negative phase of the Pacific Decadal Oscillation. Large-scale (between regions) and fine-scale (within regions) spatial and interspecies differences were apparent. In the Western Subarctic, all species tended to consume zooplankton. In the Bering Sea, chum consumed zooplankton, while sockeye and pink alternated between zooplankton and micronekton. In the Gulf of Alaska/Eastern Subarctic, chum and sockeye specialized on gelatinous zooplankton and cephalopod prey, respectively, while pink consumed a mixture of zooplankton and micronekton. The highest diet overlap across the North Pacific was between pink and sockeye (46.6%), followed by chum and pink (31.8%), and chum and sockeye (30.9%). Greater diet specialization was evident in the Gulf of Alaska/Eastern Subarctic compared to the Western Pacific. Generally, species had higher niche width and overlap in areas of high prey availability, and this was particularly evident for chum salmon. In addition to the large-scale trophic patterns, our data revealed novel fine-scale spatial patterns, including latitudinal, onshore-offshore, and cross-gyre gradients. Our results showed that pink tended to be more generalist consumers, and their diets may be a better reflection of overall prey presence and abundance in the environment. Conversely, chum and sockeye tended to be more specialist consumers, and their diets may provide a better reflection of interspecies dynamics or prey availability. This study provides a baseline for comparison with current and future changes in salmon marine ecology and North Pacific ecosystems. Finally, we identify two important data gaps that need addressing, that of improved taxonomic resolution diet data for Pacific salmon and focused research on sub-mesoscale oceanographic features that may play an important role in salmon health and productivity.

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