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

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.

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

10.7287/peerj.preprints.2190 ◽

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.

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

10.7287/peerj.preprints.2190v2 ◽

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.

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How patch size and habitat complexity changes interaction strength and population dynamics: a combined individual-based and population-based modeling experiment

10.7287/peerj.preprints.2190v1 ◽

2016 ◽

Author(s):

Yuanheng Li ◽

Ulrich Brose ◽

Katrin Meyer ◽

Björn C Rall

Keyword(s):

Functional Response ◽

Habitat Complexity ◽

Patch Size ◽

Interaction Strength ◽

Population Based ◽

Functional Responses ◽

Predator Prey Model ◽

Population Dynamic Model ◽

Modeling Experiment ◽

Feeding Interactions

Understanding how functional responses (non-linear prey density dependent feeding interactions) are affected by patch size and habitat complexity is crucial as functional responses are the major determinants of food web stability and subsequently biodiversity. Due to its laborious character, measuring empirical functional responses systematically across large gradients of patch sizes and habitat complexity independently is almost impossible. Here we overcame this issue by using an individual-based predator-prey model allowing to simulate functional responses in patches ranging from the size of petri dishes to natural patches in the field. Moreover we are able to vary the habitat complexity independent of the patch size. Contradicting to the pervasive type II functional response that is still assumed as the appropriate model to describe feeding interactions we found a type III functional response in our simulations, independent of patch size and habitat complexity. Moreover, half-saturation density determining the feeding success at low prey densities decrease only with increasing habitat complexity and is only marginally influenced by patch size. Subsequent population dynamic model simulations indicate that small patches do not allow for survival of the predator, caused by a mismatch of the nearly constant functional response but an increasing extinction boundary with decreasing patch size. This effect is counteracted by increasing habitat complexity allowing both, the prey and the predator to co-exist. Our results underline the need for protecting large patches with high habitat complexity to sustain biodiversity.

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Impact of Fear and Habitat Complexity in a Predator-Prey System with Two Different Shaped Functional Responses: A Comparative Study

Discrete Dynamics in Nature and Society ◽

10.1155/2021/6427864 ◽

2021 ◽

Vol 2021 ◽

pp. 1-22

Author(s):

Debgopal Sahoo ◽

Guruprasad Samanta ◽

Manuel De la Sen

Keyword(s):

Steady State ◽

Functional Response ◽

Habitat Complexity ◽

Lower Degree ◽

Encounter Rate ◽

Reproduction Rate ◽

Stable Limit ◽

Functional Responses ◽

Predator Prey ◽

Predator Prey Model

Habitat complexity or the structural complexity of habitat reduces the available space for interacting species, and subsequently, the encounter rate between the prey and predator is decreased significantly. Different experimental shreds of evidence validate that the presence of the predator strongly affects the physiological behaviour of prey individuals and dramatically reduces their reproduction rate. In this study, we investigate the interplay between the level of fear and the degree of habitat complexity in a predator-prey model with two different shaped functional responses. We, therefore, develop the functional response using the timescale separation method, and the shape of the resulting functional response depends upon the monotonous property of catch rate, g N where N is the prey biomass. Whenever g N increases strictly, a saturating functional response occurs, but for nonmonotonic g N , a dome-shaped functional response arises. For saturating case, it has been revealed that both prey and predator biomass may oscillate for lower levels of fear and a lower degree of habitat complexity. To stabilize this oscillatory behaviour to a coexistence state, we have to adequately increase the level of fear or degree of habitat complexity. However, for dome-shaped case, more complicated dynamics are observed. In this case, coexistence steady state, if exists, may be locally asymptotically stable for a lower degree of habitat complexity, but for intermediate values, the system is capable of producing multiple coexistence steady states with a bistable phenomenon between predator-free steady state and a coexistence steady state. Moreover, if the level of fear is sufficiently low, the system may experience a supercritical or/and subcritical Hopf bifurcation. In the dynamics of parametric disturbance for the degree of habitat complexity parameter, dome-shaped functional response predicts that disturbance may trap the system into a nearest attractor (either a large amplitude stable limit cycle or predator-free steady state); this can be overcome only by a larger alteration, or sometimes it is impossible to overcome (hysteresis phenomena), whereas the saturating-shaped functional response predicts a system resilience. For both the functional responses, a higher degree of habitat complexity always increases the extinction possibility of the predator, and no level of fear can compensate this biodiversity loss.

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Permanence of Periodic Predator-Prey System with Functional Responses and Stage Structure for Prey

Abstract and Applied Analysis ◽

10.1155/2008/371632 ◽

2008 ◽

Vol 2008 ◽

pp. 1-15 ◽

Cited By ~ 2

Author(s):

Can-Yun Huang ◽

Min Zhao ◽

Hai-Feng Huo

Keyword(s):

Functional Response ◽

Prey Species ◽

Necessary Conditions ◽

Stage Structure ◽

Functional Responses ◽

Predator Prey ◽

Predator Prey Model ◽

Prey System ◽

Sufficient And Necessary Conditions ◽

Holling Ii Functional Response

A stage-structured three-species predator-prey model with Beddington-DeAngelis and Holling II functional response is introduced. Based on the comparison theorem, sufficient and necessary conditions which guarantee the predator and the prey species to be permanent are obtained. An example is also presented to illustrate our main results.

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What drives interaction strengths in complex food webs? A test with feeding rates of a generalist stream predator

10.1101/259697 ◽

2018 ◽

Author(s):

Daniel L. Preston ◽

Jeremy S. Henderson ◽

Landon P. Falke ◽

Leah M. Segui ◽

Tamara J. Layden ◽

...

Keyword(s):

Food Webs ◽

Body Mass ◽

Prey Density ◽

Scaling Laws ◽

Community Dynamics ◽

Abiotic Factors ◽

Interaction Strength ◽

Feeding Rates ◽

Predator Prey ◽

Mass Ratios

AbstractDescribing the mechanisms that drive variation in species interaction strengths is central to understanding, predicting, and managing community dynamics. Multiple factors have been linked to trophic interaction strength variation, including species densities, species traits, and abiotic factors. Yet most empirical tests of the relative roles of multiple mechanisms that drive variation have been limited to simplified experiments that may diverge from the dynamics of natural food webs. Here, we used a field-based observational approach to quantify the roles of prey density, predator density, predator-prey body-mass ratios, prey identity, and abiotic factors in driving variation in feeding rates of reticulate sculpin (Cottus perplexus). We combined data on over 6,000 predator-prey observations with prey identification time functions to estimate 289 prey-specific feeding rates at nine stream sites in Oregon. Feeding rates on 57 prey types showed an approximately log-normal distribution, with few strong and many weak interactions. Model selection indicated that prey density, followed by prey identity, were the two most important predictors of prey-specific sculpin feeding rates. Feeding rates showed a positive, accelerating relationship with prey density that was inconsistent with predator saturation predicted by current functional response models. Feeding rates also exhibited four orders-of-magnitude in variation across prey taxonomic orders, with the lowest feeding rates observed on prey with significant anti-predator defenses. Body-mass ratios were the third most important predictor variable, showing a hump-shaped relationship with the highest feeding rates at intermediate ratios. Sculpin density was negatively correlated with feeding rates, consistent with the presence of intraspecific predator interference. Our results highlight how multiple co-occurring drivers shape trophic interactions in nature and underscore ways in which simplified experiments or reliance on scaling laws alone may lead to biased inferences about the structure and dynamics of species-rich food webs.

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Age-structured predator–prey model with habitat complexity: oscillations and control

Dynamical Systems ◽

10.1080/14689367.2012.723678 ◽

2012 ◽

Vol 27 (4) ◽

pp. 475-499 ◽

Cited By ~ 11

Author(s):

N. Bairagi ◽

D. Jana

Keyword(s):

Habitat Complexity ◽

Predator Prey ◽

Predator Prey Model ◽

Prey Model ◽

Age Structured ◽

And Control

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A Predator-Prey Model Incorporating Prey Refuge and Allee Effect

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.713-715.1534 ◽

2015 ◽

Vol 713-715 ◽

pp. 1534-1539 ◽

Cited By ~ 2

Author(s):

Rui Ning Fan

Keyword(s):

Time Delay ◽

Time Lag ◽

Functional Responses ◽

Prey Refuge ◽

Predator Prey ◽

Interior Equilibrium ◽

Predator Prey Model ◽

Prey Model ◽

Discrete Time Delay ◽

Prey Interaction

The effect of refuge used by prey has a stabilizing impact on population dynamics and the effect of time delay has its destabilizing influences. Little attention has been paid to the combined effects of prey refuge and time delay on the dynamic consequences of the predator-prey interaction. Here, a predator-prey model with a class of functional responses was studied by using the analytical approach. The refuge is considered as protecting a constant proportion of prey and the discrete time delay is the gestation period. We evaluated both effects with regard to the local stability of the interior equilibrium point of the considered model. The results showed that the effect of prey refuge has stronger influences than that of time delay on the considered model when the time lag is smaller than the threshold. However, if the time lag is larger than the threshold, the effect of time delay has stronger influences than that of refuge used by prey.

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