Using diel movement behavior to infer foraging strategies related to ecological and social factors in elephants

Movement Ecology

George Wittemyer¹  Iain Douglas-Hamilton³  Leo Polansky² 

[1] Graduate Degree Program in Ecology, Colorado State University, 80523-1474, Ft. Collins, Colorado, USA;Department of Fish, Wildlife, and Conservation Biology, Colorado State University, 80523-1474, Ft. Collins, Colorado, USA;Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK

关键词: Wavelets;    Socio-ecological model;    Savannah;    Optimal foraging theory;    Movement ecology;    Generalized linear mixed model;    Fourier analysis;   

Others  :  802631
DOI  :  10.1186/2051-3933-1-13

 received in 2013-07-18, accepted in 2013-11-04,  发布年份 2013

【 摘 要 】

Background

Adaptive movement behaviors allow individuals to respond to fluctuations in resource quality and distribution in order to maintain fitness. Classically, studies of the interaction between ecological conditions and movement behavior have focused on such metrics as travel distance, velocity, home range size or patch occupancy time as the salient metrics of behavior. Driven by the emergence of very regular high frequency data, more recently the importance of interpreting the autocorrelation structure of movement as a behavioral metric has become apparent. Studying movement of a free ranging African savannah elephant population, we evaluated how two movement metrics, diel displacement (DD) and movement predictability (MP - the degree of autocorrelated movement activity at diel time scales), changed in response to variation in resource availability as measured by the Normalized Difference Vegetation Index. We were able to capitalize on long term (multi-year) yet high resolution (hourly) global positioning system tracking datasets, the sample size of which allows robust analysis of complex models. We use optimal foraging theory predictions as a framework to interpret our results, in particular contrasting the behaviors across changes in social rank and resource availability to infer which movement behaviors at diel time scales may be optimal in this highly social species.

Results

Both DD and MP increased with increasing forage availability, irrespective of rank, reflecting increased energy expenditure and movement predictability during time periods of overall high resource availability. However, significant interactions between forage availability and social rank indicated a stronger response in DD, and a weaker response in MP, with increasing social status.

Conclusions

Relative to high ranking individuals, low ranking individuals expended more energy and exhibited less behavioral movement autocorrelation during lower forage availability conditions, likely reflecting sub-optimal movement behavior. Beyond situations of contest competition, rank status appears to influence the extent to which individuals can modify their movement strategies across periods with differing forage availability. Large-scale spatiotemporal resource complexity not only impacts fine scale movement and optimal foraging strategies directly, but likely impacts rates of inter- and intra-specific interactions and competition resulting in socially based movement responses to ecological dynamics.

【 授权许可】

   
2013 Polansky et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

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【 参考文献 】

• [1]Fryxell JM, Wilmshurst JF, Sinclair ARE: Predictive models of movement by Serengeti grazers. Ecology 2004, 85:2429-2435.
• [2]van Moorter B, Bunnefeld N, Panzacchi M, Rolandsen CM, Solber EJ, Sæther B-E: Understanding scales of movement: animals ride waves and ripples of environmental change. J Anim Ecol 2013, 2:770-780.
• [3]Nathan R, Getz WM, Revilla E, Holyoak M, Kadmon R, Saltz D, Smouse PE: A movement ecology paradigm for unifying organismal research. Proc Natl Acad Sci 2008, 105:19052-19059.
• [4]Owen-Smith N, Fryxell JM, Merrill EH: Foraging theory upscaled: the behavioural ecology of herbivore movement. Philos Trans R Soc B 2010, 365:2267-2278.
• [5]Thouless CR: Feeding competition between grazing red deer hinds. Anim Behav 1990, 40:105-111.
• [6]Wittemyer G, Getz WM, Volllrath F, Douglas-Hamilton I: Social dominance, seasonal movements, and spatial segregation in African elephants: a contribution to conservation behavior. Behav Ecol Sociobiol 2007, 61:1919-1931.
• [7]Wrangham R: An ecological model of female-bonded primate groups. Behaviour 1980, 75:262-300.
• [8]Charnov EL: Optimal foraging, the marginal value theorem. Theor Popul Biol 1976, 9:129-136.
• [9]Calhoun JB: Diel activity rhythms of the rodents, Microtus ochrogaster and Sigmodon hispidus hispidus. Ecology 1945, 26:251-273.
• [10]Closs GP, Hansen EA: Diel activity and home range size in relation to food supply in a drift-feeding stream fish. Behav Ecol 2005, 16:640-648.
• [11]Lampert W: The adaptive significance of diel vertical migration of zooplankton. Funct Ecol 1989, 3:21-27.
• [12]Boyce MS, Pitt J, Northrup JM, Morehouse AT, Knopff KH, Cristtescu B, Stenhouse GB: Temporal autocorrelation functions for movement rates from global positioning system radiotelemetry data. Philos Trans R Soc B 2010, 365:2213-2219.
• [13]Brillinger DR, Preisler HK, Ager AA, Kie JG: An exploratory data analysis (EDA) of the paths of moving animals. J Stat Plann Inference 2004, 122:43-63.
• [14]Polansky L, Wittemyer G, Cross P, Tambling CJ, Getz WM: From moonlight to movement, and synchronized randomness: Fourier and wavelet analyses of animal location time series data. Ecology 2010, 91:1506-1518.
• [15]Wittemyer G, Polansky L, Douglas-Hamilton I, Getz WM: Disentangling the effects of forage, social rank, and risk on movement autocorrelation of elephants using Fourier and wavelet analyses. Proc Natl Acad Sci USA 2008, 105:19108-19113.
• [16]Norsica I, Carrai V, Borgognini-Tarli SM: Influence of dry season and food quality and quantity on behavior and feeding strategy of Propithecus verreauxi in Kirindy, Madagascar. Int J Primatol 2006, 27:1001-1022.
• [17]Birkett PJ, Vanak AT, Muggeo VMR, Ferreira SM, Slotow R: Animal perception of seasonal thresholds: changes in elephant movement in relation to rainfall patterns. PLoS ONE 2012, 7:e38363.
• [18]Cushman SA, Chase M, Griffin C: Elephants in space and time. Oikos 2005, 109:331-341.
• [19]Polansky L, Wittemyer G: A framework for understanding the architecture of collective movements using pairwise analyses of animal movement data. J R Soc Interface 2011, 8:322-333.
• [20]Boettiger AN, Wittemyer G, Starfield R, Volrath F, Douglas-Hamilton I, Getz WM: Inferring ecological and behavioral drivers of African elephant movement using a linear filtering approach. Ecology 2011, 92:1648-1657.
• [21]Bailey DW, Gross JE, Laca EA, Rittenhouse LR, Coughenour MB, Swift DM, Sims PL: Mechanisms that result in large herbivore grazing distribution patterns. J Range Manage 1996, 49:386-400.
• [22]Fryxell JM, Wilmshurst JF, Sinclair ARE, Haydon DT, Holt RD, Abrams PA: Landscape scale, heterogeneity, and the viability of Serengeti grazers. Ecol Lett 2005, 8:328-335.
• [23]Mueller T, Fagan WF: Search and navigation in dynamic environments - from individual behaviors to population distributions. Oikos 2008, 117:654-664.
• [24]Wittemyer G, Daballen D, Douglas-Hamilton I: Comparative demography of an at-risk African elephant population. PLoS ONE 2013, 8:e53726.
• [25]Byrne RW, Bates LA, Moss CJ: Elephant cognition in primate perspective. Comp Cogn Behav Rev 2009, 4:1-15.
• [26]Wittemyer G, Ganswindt A, Hodges K: The impact of ecological variability on the reproductive endorinology of wild female African elephants. Horm Behav 2007, 51:346-354.
• [27]Hawkes C: Linking movement behavior, dispersal and population processes: is individual variation a key? J Anim Ecol 2009, 78:894-906.
• [28]Pyke GH: Optimal foraging theory - a critical review. Annu Rev Ecol Syst 1984, 15:523-575.
• [29]Wittemyer G, Douglas-Hamilton I, Getz WM: The socioecology of elephants: analysis of the processes creating multitiered social structures. Anim Behav 2005, 69:1357-1371.
• [30]Wittemyer G, Getz WM: Hierarchical dominance structure and social organization in African elephants. Anim Behav 2007, 73:671-681.
• [31]Wittemyer G, Getz WM: A likely ranking interpolation for resolving dominance orders in systems with unknown relationships. Behaviour 2006, 143:909-930.
• [32]Landau HG: On dominance relations and the structure of animal societies: i effect of inherent characteristics. Bull Math Biophys 1951, 13:1-19.
• [33]Noë R, de Waal FBM, van Hooff JARAM: Types of dominance in a chimpanzee colony. Folia Primatol 1980, 34:90-110.
• [34]Rasmussen HB, Wittemyer G, Douglas-Hamilton I: Predicting time-specific changes in demographic processes using remote-sensing data. J Appl Ecol 2006, 43:366-376.
• [35]Torrence C, Compo GP: A practical guide to wavelet analysis. Bull Am Meteorol Soc 1998, 79:61-78.
• [36]Maraun D, Kurths J: Cross wavelet analysis: significance testing and pitfalls. Nonlinear Process Geophys 2004, 11:505-514.
• [37]Maraun D, Kurths J, Holschneider M: Nonstationary Gaussian processes in wavelet domain: synthesis, estimation, and significance testing. Phys Rev E 2007. 016707-1:016707-14
• [38]Bolker BM, Brooks ME, Clark CJ, Geange SW, Poulsen JR, Stevens MHH, White J-SS: Generalized linear mixed models: a practical guide for ecology and evolution. Trends Ecol Evol 2009, 24:127-135.
• [39]Bates D, Maechler M, Bolker B: lme4: linear mixed-effects models using S4 classes. R package version 0.999999-0, 2012 [http://CRAN.R-project.org/ webcite]
• [40]Team RC: R: A Language and Environment for Statistical Computing. Vienna: Austria; 2012.
• [41]Venables WN, Ripley BD: Modern Applied Statistics with S. 4th edition. Springer-Verlag New York: New York, NY; 2002.