Population Dynamics and Mutualism: Functional Responses of Benefits and Costs

2002 ◽  
Vol 159 (3) ◽  
pp. 231
Author(s):  
Holland ◽  
DeAngelis ◽  
Bronstein
Keyword(s):  
Population Dynamics ◽  
Functional Responses ◽  
Benefits And Costs

Population Dynamics and Mutualism: Functional Responses of Benefits and Costs

2002 ◽  
Vol 159 (3) ◽  
pp. 231-244 ◽  
Author(s):  
J. Nathaniel Holland ◽  
Donald L. DeAngelis ◽  
Judith L. Bronstein
Keyword(s):  
Population Dynamics ◽  
Functional Responses ◽  
Benefits And Costs

scholarly journals Testing predator - prey theory by studying fluctuating populations of small mammals.

1995 ◽  
Vol 22 (1) ◽  
pp. 89 ◽  
Author(s):  
S. Boutin
Keyword(s):  
Population Dynamics ◽  
Small Mammals ◽  
Limit Cycles ◽  
Functional Responses ◽  
Predator Satiation ◽  
Linear Type ◽  
Small Component ◽  
Wide Range ◽  
Fluctuating Populations

Fluctuating populations of small mammals provide an excellent opportunity to study the functional and numerical responses of predators because of the wide range in prey density that occurs. I reinterpret data from six studies that have examined the role of predation in the population dynamics of voles in California, southern Sweden and western Finland, of snowshoe hares in northern Canada, and of house mice and rabbits in Australia. Most studies have measured functional responses by relying on changes in diet as reflected by scat or stomach contents. These methods are probably biased toward showing predator satiation. Contrary to previous conclusions I find that there is little evidence for non-linear (Type 111) functional-response curves or predator satiation at high prey densities. Recent studies indicate that the functional and numerical responses of predators can be rapid and strong enough to initiate cyclic declines, dampen fluctuations, or even cause stable numbers. The exception to this appears to be the irruptions of mice and rabbits in Australia. I propose a general explanation for the role of predation whereby the effect of predation is largely dependent on the entire prey community. When potentially cyclic prey are a small component of the overall prey biomass, generalist predators are able to prevent fluctuations by strong functional or numerical responses. As the prey community becomes dominated by a few species that fluctuate, limit cycles predominate. Limit cycles turn into irruptive population dynamics when seasonal prey reproduction is eliminated because of extended periods of vegetation growth (vegetation flushes following drought). In the future we must test assumptions underlying the way we study predation by telemetric monitoring of prey mortality and by experimentally manipulating predation.

POPULATION DYNAMICS OF THE CABBAGE APHID, BREVICORYNE BRASSICAE (HOMOPTERA: APHIDIDAE) AT VANCOUVER, BRITISH COLUMBIA: V. A SIMULATION MODEL

1984 ◽  
Vol 116 (6) ◽  
pp. 895-911 ◽  
Author(s):  
D. A. Raworth
Keyword(s):  
British Columbia ◽  
Population Dynamics ◽  
Major Change ◽  
Brevicoryne Brassicae ◽  
Diaeretiella Rapae ◽  
Simulated Population ◽  
Aphidoletes Aphidimyza ◽  
Functional Responses ◽  
Cabbage Aphid ◽  
Effects Of Temperature

AbstractA computer model was written to simulate the population dynamics of the cabbage aphid, Brevicoryne brassicae (L.), on the host Maris Kestrel kale, Brassica oleracea L., at Vancouver, British Columbia. The model incorporated the effects of temperature, morph determination, plant quality, predators, parasites, and leaf fall. Comparisons of simulated results with field observations indicated that although B. brassicae, Aphidoletes aphidimyza (Rond.), and Diaeretiella rapae (M'Intosh) were reasonably well understood, syrphid predation was not, and appropriate feed-back mechanisms which could prevent monotonic increase or decrease in the simulated population were lacking. A detailed study in which the population dynamics of the prey is accounted for in terms of the numerical and functional responses of syrphid predators is necessary to understand the population dynamics of B. brassicae on Maris Kestrel kale at Vancouver. Comparisons with other aphid systems suggest that a major change in one component of the system can be compensated for by changes in other components. An overview of the cabbage aphid system at Vancouver is given.

scholarly journals How patch size and refuge availability change interaction strength and population dynamics: a combined individual- and population-based modeling experiment

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2993 ◽  
Author(s):  
Yuanheng Li ◽  
Ulrich Brose ◽  
Katrin Meyer ◽  
Björn C. Rall
Keyword(s):  
Population Dynamics ◽  
Habitat Complexity ◽  
Patch Size ◽  
Feeding Rate ◽  
Interaction Strength ◽  
Time Frame ◽  
Feeding Rates ◽  
Functional Responses ◽  
Predator Prey ◽  
Predator Prey Model

Knowledge on how functional responses (a measurement of feeding interaction strength) are affected by patch size and habitat complexity (represented by refuge availability) is crucial for understanding food-web stability and subsequently biodiversity. Due to their laborious character, it is almost impossible to carry out systematic empirical experiments on functional responses across wide gradients of patch sizes and refuge availabilities. Here we overcame this issue by using an individual-based model (IBM) to simulate feeding experiments. The model is based on empirically measured traits such as body-mass dependent speed and capture success. We simulated these experiments in patches ranging from sizes of petri dishes to natural patches in the field. Moreover, we varied the refuge availability within the patch independently of patch size, allowing for independent analyses of both variables. The maximum feeding rate (the maximum number of prey a predator can consume in a given time frame) is independent of patch size and refuge availability, as it is the physiological upper limit of feeding rates. Moreover, the results of these simulations revealed that a type III functional response, which is known to have a stabilizing effect on population dynamics, fitted the data best. The half saturation density (the prey density where a predator consumes half of its maximum feeding rate) increased with refuge availability but was only marginally influenced by patch size. Subsequently, we investigated how patch size and refuge availability influenced stability and coexistence of predator-prey systems. Following common practice, we used an allometric scaled Rosenzweig–MacArthur predator-prey model based on results from ourin silicoIBM experiments. The results suggested that densities of both populations are nearly constant across the range of patch sizes simulated, resulting from the constant interaction strength across the patch sizes. However, constant densities with decreasing patch sizes mean a decrease of absolute number of individuals, consequently leading to extinction of predators in the smallest patches. Moreover, increasing refuge availabilities also allowed predator and prey to coexist by decreased interaction strengths. Our results underline the need for protecting large patches with high habitat complexity to sustain biodiversity.

scholarly journals How patch size and refuge availability change interaction strength and population dynamics: a combined individual- and population-based modeling experiment

2016 ◽  
Author(s):  
Yuanheng Li ◽  
Ulrich Brose ◽  
Katrin Meyer ◽  
Björn C Rall
Keyword(s):  
Population Dynamics ◽  
Habitat Complexity ◽  
Patch Size ◽  
Feeding Rate ◽  
Interaction Strength ◽  
Time Frame ◽  
Feeding Rates ◽  
Functional Responses ◽  
Predator Prey ◽  
Predator Prey Model

Knowledge on how functional responses (a measurement of feeding interaction strength) are affected by patch size and habitat complexity (represented by refuge availability) is crucial for understanding food-web stability and subsequently biodiversity. Due to their laborious character, it is almost impossible to carry out systematic empirical experiments on functional responses across wide gradients of patch sizes and refuge availabilities. Here we overcame this issue by using an individual-based model (IBM) to simulate feeding experiments. The model is based on empirically measured traits such as body size dependent speed and capture success. We simulated these experiments in patches ranging from size of petri dishes to natural patches in the field. Moreover, we varied the refuge availability within the patch independently of patch size, allowing for an independent analyses of both variables. The maximum feeding rate (the maximum number of prey a predator can consume in a given time frame) is independent of patch size and refuge availability, as it is the physiological upper limit of feeding rates. Moreover, the results of these simulations revealed that a type III functional response, which is known to have a stabilizing effect on population dynamics, fits the data best. The half saturation density (the prey density where a predator consumes half of its maximum feeding rate) increased with refuge availability but was only marginally influenced by patch size. Subsequently, we investigated how patch size and refuge availability influence stability and coexistence of predator-prey systems. Following common practice, we used an allometric scaled Rosenzweig-MacArthur predator-prey model based on results from our in silico IBM experiments. The results suggested that densities of both populations are nearly constant across the range of patch sizes simulated, resulting from the constant interaction strength across the patch sizes. However, constant densities with decreasing patch sizes mean a decrease of absolute number of individuals, consequently leading to extinction of predators in smallest patches. Moreover, increasing refuge availabilities also allowed predator and prey to coexist by decreased interaction strengths. Our results underline the need for protecting large patches with high habitat complexity to sustain biodiversity.

scholarly journals How patch size and refuge availability change interaction strength and population dynamics: a combined individual- and population-based modeling experiment

2016 ◽  
Author(s):  
Yuanheng Li ◽  
Ulrich Brose ◽  
Katrin Meyer ◽  
Björn C Rall
Keyword(s):  
Population Dynamics ◽  
Habitat Complexity ◽  
Patch Size ◽  
Feeding Rate ◽  
Interaction Strength ◽  
Time Frame ◽  
Feeding Rates ◽  
Functional Responses ◽  
Predator Prey ◽  
Predator Prey Model

Knowledge on how functional responses (a measurement of feeding interaction strength) are affected by patch size and habitat complexity (represented by refuge availability) is crucial for understanding food-web stability and subsequently biodiversity. Due to their laborious character, it is almost impossible to carry out systematic empirical experiments on functional responses across wide gradients of patch sizes and refuge availabilities. Here we overcame this issue by using an individual-based model (IBM) to simulate feeding experiments. The model is based on empirically measured traits such as body size dependent speed and capture success. We simulated these experiments in patches ranging from size of petri dishes to natural patches in the field. Moreover, we varied the refuge availability within the patch independently of patch size, allowing for an independent analyses of both variables. The maximum feeding rate (the maximum number of prey a predator can consume in a given time frame) is independent of patch size and refuge availability, as it is the physiological upper limit of feeding rates. Moreover, the results of these simulations revealed that a type III functional response, which is known to have a stabilizing effect on population dynamics, fits the data best. The half saturation density (the prey density where a predator consumes half of its maximum feeding rate) increased with refuge availability but was only marginally influenced by patch size. Subsequently, we investigated how patch size and refuge availability influence stability and coexistence of predator-prey systems. Following common practice, we used an allometric scaled Rosenzweig-MacArthur predator-prey model based on results from our in silico IBM experiments. The results suggested that densities of both populations are nearly constant across the range of patch sizes simulated, resulting from the constant interaction strength across the patch sizes. However, constant densities with decreasing patch sizes mean a decrease of absolute number of individuals, consequently leading to extinction of predators in smallest patches. Moreover, increasing refuge availabilities also allowed predator and prey to coexist by decreased interaction strengths. Our results underline the need for protecting large patches with high habitat complexity to sustain biodiversity.

Persistence of a surrogate for a genetically engineered cellulolytic microorganism and effects on aquatic community and ecosystem properties: mesocosm and stream comparisons

1993 ◽  
Vol 39 (7) ◽  
pp. 686-700 ◽  
Author(s):  
Thomas L. Bott ◽  
Louis A. Kaplan
Keyword(s):  
Population Dynamics ◽  
Leaf Litter ◽  
Litter Decomposition ◽  
Bacterial Population ◽  
Genetically Engineered ◽  
Community Respiration ◽  
Cladophora Glomerata ◽  
Bacterial Productivity ◽  
Functional Responses ◽  
Leaf Packs

Our research objectives were to (i) determine the persistence of an introduced surrogate (Cellulomonas sp. NRC 2406) for a genetically engineered microorganism in sediments, growths of Cladophora glomerata (Chlorophyta), and leaf packs, (ii) test community and ecosystem structural and functional responses to the introduced bacteria, and (iii) evaluate the utility of flowing water mesocosms as tools for assessing the fates and effects of introduced bacteria in streams. Cellulomonas sp. densities were determined using fluorescent antibodies; maxima were ≤ 1% of the total bacterial community in each habitat in two experiments, and ≈25% of total densities in leaf packs in a third experiment. Densities declined from postinoculation maxima faster in sediments than in C. glomerata growths and leaf packs. Cellulomonas sp. persisted in leaf packs at densities significantly greater than background. Cellulomonas sp. had no statistically significant effects on primary productivity, community respiration, assimilation ratios, photosynthesis/respiration (P/R) ratios, bacterial productivity, and leaf litter decomposition rates. Cellulase concentrations were positively correlated with Cellulomonas sp. densities ≥ 7 × 108 cells/g dry mass in fresh leaf litter for 2 days following exposure. Total bacterial densities, algal biomass, and total viable biomass sometimes differed between control and experimental systems, but differences were not related to Cellulomonas sp. introduction. Mesocosms were good tools for studying bacterial population dynamics in leaf litter and physiological aspects of litter degradation, but they were less well suited to measuring losses of litter mass and cellulose because physical abrasion during storms accelerated those processes in the field.Key words: bacterial population dynamics, mesocosms, streams, introduced bacteria, Cellulomonas sp., litter decomposition.

Interactions between leaf-cutter ants and fungus garden: Effects of division of labor, age polyethism, and egg cannibalism

2018 ◽  
Vol 13 (3) ◽  
pp. 30 ◽  
Author(s):  
Marisabel Rodriguez Rodriguez ◽  
Nathan Smith ◽  
Tin Phan ◽  
Jonathan Woodbury ◽  
Yun Kang
Keyword(s):  
Population Dynamics ◽  
Division Of Labor ◽  
Interaction Model ◽  
Species Interaction ◽  
Conflict Behavior ◽  
Age Polyethism ◽  
Functional Responses ◽  
Egg Cannibalism ◽  
Oscillatory Dynamics ◽  
Cannibalism Rate

Division of labor (DOL), age polyethism, and egg cannibalism all play roles in shaping colony-level population dynamics in social insect colonies. The ways in which these mechanisms interact with one another to shape population dynamics is not currently understood. In this study, we examine how these mechanisms influence population dynamics in colonies of fungus-gardening leaf-cutter ants by developing and studying two sets of models: (1) We study age polyethism contribution to the dynamics of this multi-species interaction model which incorporates mechanisms of DOL; (2) We explore effects of egg cannibalism in colony dynamics and understand how to model such social conflict behavior realistically using different functional responses. Our results suggest that: (a) Age polyethism is important to keep stable population dynamics. (b) Large maturation rate and mortality rate of inside workers induce colony death. (c) Small enough egg cannibalism rate benefits adult worker ant’s growth and (or) development, large proportion of ants performing a given task can promote colony survival, and too large egg cannibalism rate can lead to colony’s death. (d) Increasing energy invested on brood care and (or) the conversion rate between fungus and ants could induce oscillatory dynamics in models with cannibalism.

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