scholarly journals Effect of predator–prey and competitive interactions on size at emergence in the black-lip abalone Haliotis rubra in a Tasmanian MPA

2008 ◽  
Vol 366 ◽  
pp. 91-98 ◽  
Author(s):  
HG Pederson ◽  
NS Barrett ◽  
SD Frusher ◽  
CD Buxton
Keyword(s):  
Competitive Interactions ◽  
Predator Prey ◽  
Haliotis Rubra

Distribution patterns of vertebrate and invertebrate planktivores in Newfoundland lakes with evidence of predator–prey and competitive interactions

1990 ◽  
Vol 68 (7) ◽  
pp. 1559-1567 ◽  
Author(s):  
Christine E. Campbell ◽  
Roy Knoechel
Keyword(s):  
Gasterosteus Aculeatus ◽  
Spatial Separation ◽  
Distribution Patterns ◽  
Competitive Interactions ◽  
Cyclopoid Copepod ◽  
Predator Prey ◽  
Interacting Species ◽  
Leptodora Kindtii ◽  
Faunal Diversity ◽  
Avalon Peninsula

The vertebrate Gasterosteus aculeatus, the threespine stickleback, and the invertebrates Chaoborus punctipennis, Chaoborus trivittatus, and Leptodora kindtii are the major predators of zooplankton in lakes on the Avalon Peninsula, Newfoundland. Predator–prey and competitive interactions among these planktivores are potentially strong. Low faunal diversity in the lakes limits the number of interacting species, which may increase the intensity of the interactions, while the low habitat heterogeneity of the lakes decreases the probability of spatial separation of species to increase rates of species encounters. Analyses of distributional patterns (presence or absence data) of the planktivores in 15 Avalon lakes indicated that the distributions of both Chaoborus spp. were significantly and negatively related to the distribution of sticklebacks. Chaoborus densities were significantly higher in the lakes without sticklebacks. Sticklebacks were observed to eat third and fourth instars of both Chaoborus species in laboratory experiments and hence, through predation, may be able to exclude these species from some lakes. There was no significant relationship between the distributions of Leptodora and sticklebacks or between Leptodora and C. punctipennis, however the distributions of Leptodora and C. trivittatus were significantly and negatively related, indicating a possible competitive interaction. Environmental factors also influence planktivore distribution and abundance: a principal components factor derived from planktivore density data was significantly correlated with cyclopoid copepod biomass, lake SO4 levels, and lake surface area (multiple linear regression, r2 = 0.71).

scholarly journals The cost of attack in competing networks

2015 ◽  
Vol 12 (112) ◽  
pp. 20150770 ◽  
Author(s):  
B. Podobnik ◽  
D. Horvatic ◽  
T. Lipic ◽  
M. Perc ◽  
J. M. Buldú ◽  
...  
Keyword(s):  
Real World ◽  
Conservation Law ◽  
Feedback Mechanism ◽  
Competitive Interactions ◽  
Predator Prey ◽  
Network Competition ◽  
Optimal Duration ◽  
Target Network ◽  
Negative Impacts ◽  
The Cost

Real-world attacks can be interpreted as the result of competitive interactions between networks, ranging from predator–prey networks to networks of countries under economic sanctions. Although the purpose of an attack is to damage a target network, it also curtails the ability of the attacker, which must choose the duration and magnitude of an attack to avoid negative impacts on its own functioning. Nevertheless, despite the large number of studies on interconnected networks, the consequences of initiating an attack have never been studied. Here, we address this issue by introducing a model of network competition where a resilient network is willing to partially weaken its own resilience in order to more severely damage a less resilient competitor. The attacking network can take over the competitor's nodes after their long inactivity. However, owing to a feedback mechanism the takeovers weaken the resilience of the attacking network. We define a conservation law that relates the feedback mechanism to the resilience dynamics for two competing networks. Within this formalism, we determine the cost and optimal duration of an attack, allowing a network to evaluate the risk of initiating hostilities.

Fight for Life

2015 ◽  
Vol 77 (9) ◽  
pp. 693-698 ◽  
Author(s):  
Jennifer M. Clark ◽  
Matthew T. Begley
Keyword(s):  
Predation Risk ◽  
Optimal Foraging ◽  
Optimal Foraging Theory ◽  
Foraging Theory ◽  
Competitive Interactions ◽  
Predator Prey ◽  
Trade Offs ◽  
Ecological Concepts ◽  
Energy Trade ◽  
Giving Up Density

Optimal foraging theory explains that organisms whose foraging is as energetically efficient as possible should be favored by natural selection. However, many individuals must exhibit trade-offs between foraging and other factors in their environment (i.e., predation risk, competitive interactions). We present a hands-on activity for undergraduates using just a deck of cards, bingo chips, and dice to introduce ecological concepts of foraging theory, predator–prey interactions, and energy trade-offs. Specifically, this activity will focus on optimal foraging theory and giving-up density. Students should gain an understanding of how organisms balance predation risk and competitive interactions with energetic demands. Further, this activity can be scaled for nonmajors and introductory courses to introduce general ecological concepts, or for upper-division courses to explore advanced topics in foraging theory.

Cognition in predator-prey systems: Searching image and prey polymorphism

1997 ◽  
Author(s):  
Alan B. Bond ◽  
Alan C. Kamil ◽  
Christopher Cink
Keyword(s):  
Predator Prey
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