Abstract Under the current paradigm, organic matter decomposition and nutrient cycling rates are a function of the imbalance between substrate and microbial biomass stoichiometry. Figure 1 Open in figure viewer PowerPoint.
Conceptual diagram of the microbial functional groups model. Solid arrows depict mass flow of C and N. Dotted arrows depict the catalytic effect of a certain enzyme pool on the breakdown of its respective complex substrate for details on enzymatic breakdown see Appendix S2. Bold blue and red arrows indicate diffusion for details on diffusion algorithm see Appendix S3. All transformations are calculated once per time step for each microsite on the grid at a random order.
DOM, dissolved organic material. DIN: dissolved inorganic nitrogen. Microbial processing of C and N and stoichiometric overflow Microbes take up C and N in the ratio present in the DOM pool at their microsite at a rate related to cell surface area Appendix S1. Functional traits A functional microbial group is composed of microbes with certain functional traits. Turnover rates are cell size dependent because: 1 growth is related to cell size based on the assumption that uptake is surface dependent and smaller cells have a larger surface to volume ratio, i.
For more details, see Appendix S1. Fast Slow Max cell size Size at which a microbial cell divides and colonises a neighbouring microsite 10 fmol C Max cells ms Max. Cell stoichiometries presented here have also been used as assumptions for the three distinct functional groups used in the Bayesian calibration of the model. Figure 2 Open in figure viewer PowerPoint. Remaining carbon is calculated from measured respiration rates during the litter decomposition study.
Model parameter settings are given in Table S1. Empirical data from incubations at initial litter Figure 3 Open in figure viewer PowerPoint. Relative amounts of each substrate per microsite are indicated by the colour code in the lower left corner. Inserted figures on the right show the aggregated sizes of the respective pools as calculated from the model output.
For detailed parameter settings, see Table S1 and main text. Figure 4 Open in figure viewer PowerPoint. The upper left panel thus shows model dynamics with a uniform population both groups have equal traits. Figure 5 Open in figure viewer PowerPoint. First row: coloured lines show biomass of functional groups over time for visualising stochastic variability, each panel shows results of four model runs.
Second row: Grey and brown areas show remaining C in plant compounds and microbial necromass respectively. Third row: Grey and brown areas show enzymatic DOM production from plant material and microbial necromass respectively. Figure 6 Open in figure viewer PowerPoint. The implementation of community dynamics in the model enables a flexible response of decomposition to stoichiometric conditions. For parameter details, see Table S1. Discussion Microbial community dynamics has so far been neglected in modelling decomposition processes in terrestrial systems due to the difficulty of establishing a link between microbial community structure and function.
Authorship C. Allison, S. Cheaters, diffusion and nutrients constrain decomposition by microbial enzymes in spatially structured environments. Google Scholar. Citing Literature. Volume 17 , Issue 6 June Pages Figures References Related Information. Close Figure Viewer. Dall, S. Information and its use by animals in evolutionary ecology.
Trends Ecol. Consensus decision making in animals. Personal Ed. Canonge, S. Group living enhances individual resources discrimination: the use of public information by cockroaches to assess shelter quality. PLoS One 6 , Costa, J. The other insect societies. Belknap Press of Harvard University Press, Lowry, H. Behavioural responses of wildlife to urban environments. Silva, A.
Population and community dynamics
Artificial night lighting rather than traffic noise affects the daily timing of dawn and dusk singing in common European songbirds. Kurvers, R. Bright nights and social interactions: A neglected issue. Tarjuelo, R. Effects of human activity on physiological and behavioral responses of an endangered steppe bird. Frid, A. Human-caused disturbance as a form of predation risk.
Beale, C. Behavioural responses to human disturbance: A matter of choice? Radford, A. Acoustic communication in a noisy world: Can fish compete with anthropogenic noise? Gill, S. Toward a broader characterization of anthropogenic noise and its effects on wildlife. Moiron, M. Singing in the city: High song frequencies are no guarantee for urban success in birds. Urban habitats and feeders both contribute to flight initiation distance reduction in birds.
Microbial community dynamics alleviate stoichiometric constraints during litter decay
Bejder, L. Impact assessment research: Use and misuse of habituation, sensitisation and tolerance in describing wildlife responses to anthropogenic stimuli. Hu, X. Insect Behav. Schwinghammer, M. Gautam, B. Effects of sand moisture level on food consumption and distribution of Formosan subterranean termites Isoptera: Rhinotermitidae with different soldier proportions. Laurent Salazar, M. Collective resilience in a disturbed environment: stability of the activity rhythm and group personality in Periplaneta americana.
King, A. When to use social information: the advantage of large group size in individual decision making. Lett 3 , — What is the magnitude of the group-size effect on vigilance? Dochtermann, N. Behavioral syndromes as evolutionary constraints. Keiser, C. Personality composition is more important than group size in determining collective foraging behaviour in the wild. B Biol. Wright, C. Personality and morphology shape task participation, collective foraging and escape behaviour in the social spider Stegodyphus dumicola.
Halloy, J. Social integration of robots into groups of cockroaches to control self-organized choices. Science , —8 Ethology , — Information cascade ruling the fleeing behaviour of a gregarious insect. Group personality during collective decision-making: a multi-level approach. Crall, J. Social context modulates idiosyncrasy of behaviour in the gregarious cockroach Blaberus discoidalis.
Habitat structure helps guide the emergence of colony-level personality in social spiders. Carrete, M. Inter-individual variability in fear of humans and relative brain size of the species are related to contemporary urban invasion in birds. PLoS One 6 , e Blumstein, D. Developing an evolutionary ecology of fear: How life history and natural history traits affect disturbance tolerance in birds. Jeanson, R. Conspecific attraction and shelter selection in gregarious insects. Cuticular hydrocarbon profiles and aggregation in four Periplaneta species Insecta: Dictyoptera.
Insect Physiol. Parrish, J. Michelena, P. Effects of group size and personality on social foraging: the distribution of sheep across patches. Gosselin-ildari, A. Izutsu, M. Aggregation effects on the growth of German cockroach, Blattella germanica L. Blattaria: Blattellidae. Dambach, M. Aggregation density and longevity correlate with humidity in first-instar nymphs of the cockroach Blattella germanica L. Reduced flocking by birds on islands with relaxed predation. Proc R. Soc B , — Bell, W. The American cockroach. Chapman and Hall, Kendall, M. A new measure of rank correlation.
Biometrika 30 , 81—93 Zar, J. Biostatistical Analysis. Prentice Hall, Download references. We thank you two anonymous referees who helped to improve the manuscript. Thanks to Olivier Bles for his valuable comments. Correspondence to I. This work is licensed under a Creative Commons Attribution 4. By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate. Article metrics. Advanced search. Skip to main content.
Subjects Animal migration Behavioural ecology Social evolution. Abstract Group-level properties, such as collective movements or decisions, can be considered an outcome of the interplay between individual behavior and social interactions. Introduction A large community of researchers has been inspired by the coordinated movements and decision-making, including insect colonies, fish schools, bird flocks and mammal herds 1 , 2 , 3 , 4 , 5.
Results Personality and group size effects during the active and resting phases Groups of 20 cockroaches were tested in an arena with two identical shelters for a week see methods. Full size table. We performed two separate MANOVAs on data collected in and because the duration of the observational period varied.
Because continuous and patch reefs differ from each other in both the degree of patchiness and physical location, we performed an experiment on standard habitat units SHU in a single location to remove this potentially confounding effect from our observations. Coral rubble was placed in the center of each unit.
In the first treatment we positioned four SHUs in the corners of a square such that the center of adjacent SHUs were 1 m apart. In our second treatment SHUs were arrayed in an identical fashion, except the centers of adjacent SHUs were separated by 0. These distances were selected to reflect average nearest neighbor distances between fish see Results.
Fish were assigned haphazardly to experimental locations. Thus, each experimental plot of four SHUs received four fish. All transplanted fish remained on SHUs. Three days after we transplanted fish, we commenced 5-min focal observations. We recorded both foraging bites and agonistic behavior as we did in our observations in natural habitat. Where MANOVA detected significant differences, we tested each dependent variable feeding rate, aggression rate with t tests.
Although demography typically includes age-specific rates of movement, mortality, growth, and reproduction, we limited our demographic analyses to rates of mortality and growth. We first compared the change in standard length of fish on natural continuous and patch reefs to determine whether differences in nearest neighbor distance and behavior might affect fish growth. From 26 May to 10 June , we searched both continuous and patch reef habitat in Tague Bay for newly recruited three-spot damselfish.
Fish were collected after being anesthetized with quinaldine and were placed in plastic bags and measured to the nearest 0.
We then gave each fish a unique mark using florescent elastomer Malone et al. We censused marked fish at approximately weekly intervals until we terminated the sampling between 26 and 31 July by collecting and remeasuring all marked fish. We did not find any marked individuals that were classified as missing during the regular censuses.
Because three-spot damselfish have extremely small home ranges Itzkowitz, ; Myrberg and Thresher, ; Thresher, ; Williams, , losses of marked fish were ostensibly due to mortality rather than migration. Initial SL was included as the covariate to control for differences in the starting size of damselfish.
Before analysis, we checked data for normality, homogeneity of variance, and homogeneity of slopes. To determine whether mortality rates differed between habitats, we used Fisher's Exact test to compare the number of fish missing on continuous and patch reefs. We included only those fish that survived to their first census to control for mortality that might be attributable to handling effects. We have thus defined mortality rate as the presence of fish from the first census to the final collection.
We also examined growth rates of fish on our SHUs. After fish were captured and measured, individuals on sets of four SHUs were individually marked using fin clips. After 15 days, fish were recaptured, placed in plastic bags, and measured to the nearest 0. In both and , nearest neighbor distances on patch reefs averaged about 47 cm, while on continuous reefs nearest neighbor distances averaged about cm Figure 1.
Statistical results are given in text. Bars are 1 SE. The number of agonistic interactions in which three-spots were involved was lower on continuous and than on patch reef habitat Figure 2. SHUs were arrayed such that they were 0. Our behavioral observations of transplanted three-spot damselfish on SHUs also resembled our observations in natural habitat with clear differences in behavior between fish on SHUs separated by 0.
Damselfish on SHUs separated by 0. Mean number of bites at food or agonistic encounters on standardized habitat units separated by 0. Daily percent growth of fish on SHUs separated by 1. Statistical results are given in the text. Fifty-two fish survived on patch reefs to the first census, while 46 fish survived on continuous reefs. Species interactions have been the traditional domain of population and community ecologists.
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However, it is clear that aspects of individual behavior underlie such interactions and may thus have important ecological consequences Real, In this study, we examined how habitat structure affected patterns of fish dispersion, how fish behavior was influenced by habitat-induced differences in aggregation, and how growth and mortality rates differed as a function of these behavioral differences.
As a result, the dispersion of juvenile three-spot damselfish is closely tied to the patch structure of the reef, and density of juvenile damselfish was higher on patch reef than on continuous reef habitat nearest neighbor distances were shorter on patch than on continuous reef. The higher aggregation of fish on patch versus continuous reef appears to have resulted in a greater number of agonistic interactions on patch reef than on continuous habitat. The increased time spent on aggression on patch reefs apparently occurred at the expense of foraging, as fish on patch reefs spent less time foraging than their counterparts on continuous reefs.
The elevated rates of aggression and reduced rates of foraging on patch versus continuous reef habitat were associated with a decrease in growth rates of fish on patch reefs, although survivorship did not differ between the two habitats. Reduced growth rates have a strong potential to feed back to population dynamics in fishes. When food or access to food is limited, growth rates of fish tend to be low, and mortality rates tend to be high and negatively size selective reviewed by Sogard, Houde termed this the stage duration hypothesis.
Reduction in juvenile growth rate is coupled with increased mortality rates because fish remain in vulnerable size classes for longer periods of time. Although we were unable to detect differences in mortality rates between patch and continuous reef habitats with short-term monitoring, such differences may have become apparent had we sampled longer.
Indeed, such effects are common in fishes e. Patch and continuous reef habitats vary in many aspects other than the dispersion of coral habitat for juvenile three-spot damselfish. At our study site, patch reefs occurred in deeper water m than the continuous back reef 1. Thus, light levels, flow regime, flux of planktonic food, species and densities of potential competitors, species of corals, and other factors may have differed between the two habitats.
However, when we experimentally created standard habitats in a single location that varied only in the distance between habitat patches which reflected the nearest neighbor distance in the two natural habitats , our results were similar to those from natural habitat. On SHUs separated by 0. Thus, it is likely that differences in behavior and growth between the two natural habitats were largely the result of differences in patch structure. Resource levels clearly affect foraging rates; however, the similarity of SHU results that were conducted in Jamaica to those of St.
Croix strengthens the argument that the spatial patterning of the habitat is important. They are clearly useful when evaluating reef fishes, but there are problems with the application of both models to such species. Both distributions assume that animals can correctly assess the suitability of a patch.
The IFD also assumes that new settlers are free to enter a patch Fretwell, The territoriality and high rates of aggression displayed by three-spot damselfish suggest that new settlers may not be free to enter a patch, indicating that an IDD may be more appropriate. However, even though three-spot damselfish are highly territorial and aggressive, the IDD may not be appropriate for settlement of juvenile fishes.
Predator and Prey Models with Flexible Individual Behavior and Imperfect Information.
Because settlement generally occurs at night when diurnally active residents, including three-spot damselfish, are inactive, residents may not have the opportunity to prevent settlement into the patch e. IFD models predict that fish should leave patch reefs where interference is high for other habitats where the density of potential competitors relative to available food resources is lower. However, juvenile three-spot damselfish remained on patch reefs despite experiencing lower growth rates than those on continuous reef.
Higher than predicted use of poor patches has been observed in number of different taxa Kohlmann and Risenhoover, ; Messier et al. There are several reasons to explain why juvenile three-spots overused patch reef habitat, and these fall into a number of traditionally proposed categories: 1 inability to correctly assess patches, 2 high cost of movement among patches, 3 factors related to perceptual ability or encounter rate, and 4 unquantified costs or benefits, which in our study would most likely be early, postsettlement mortality or survivorship over a longer period than the duration of our experiments.
A likely explanation for the patterns we observed combines points one and two. Settling individuals may not be capable of correctly or completely assessing patch quality in terms of conspecific density, and the costs of postsettlement movement may be high enough to prevent redistribution of juveniles after settlement. Many reef fishes respond to the presence of conspecifics presumably because the presence of conspecifics indicates high-quality habitat Booth, ; Sweatman, ; Tolimieri, ; however, settling three-spot damselfish do not appear to respond to conspecifics Tolimieri, Even when fish respond to conspecifics, settlers may still have only partial information on the quality of the patch.
Settlement occurs at night when most diurnal residents have retreated into the reef and are inactive. Although settlers may be able to use olfactory cues to detect conspecifics Sweatman, , this may only provide them with information on presence or absence of conspecifics, not density. Once fish settle, patch movement, especially in damselfish, is minimal Doherty, ; Forrester, , ; Jones, a , b , , ; Tolimieri, In the present study, we recorded no cases of juvenile three-spots moving among patches, although they are known to move to different substrata upon reaching maturity Williams, Lack of movement after settlement alone should not exclude IFD because fish are free to choose among patches during settlement.
However, the inability to completely assess patch quality at the time of settlement in concert with lack of movement among patches after settlement may produce the deviation from predictions of both IFD and IDD models that we observed. The ability of individuals to perceive patches may also affect distribution.
Small, dispersed patches will be encountered more often than less numerous large ones e. Many ecological studies have found that rates of patch colonization are higher in small than in larger patches Bell et al. Thus, three-spot damselfish may settle in high densities on patch reefs simply because these habitats are more easily detected. In an experiment similar to the one here, Levin found higher settlement of a temperate wrasse to patchily distributed artificial habitat units than to clumped ones.
His results are relevant here because mortality rates of these recently settled fish differed such that mortality was higher on the preferred settlement patch.