https://cpw.cvlcollections.org/files/original/e5102385ded4448a7bb1dab603dfc935.pdf cd6fa9b4ebc2914e2f3eab7736133a4c PDF Text Text The research in this publication was partially or fully funded by Colorado Parks and Wildlife. Dan Prenzlow, Director, Colorado Parks and Wildlife • Parks and Wildlife Commission: Marvin McDaniel, Chair • Carrie Besnette Hauser, Vice-Chair Marie Haskett, Secretary • Taishya Adams • Betsy Blecha • Charles Garcia • Dallas May • Duke Phillips, IV • Luke B. Schafer • James Jay Tutchton • Eden Vardy �www.nature.com/scientificreports OPEN received: 10 August 2016 accepted: 24 November 2016 Published: 23 December 2016 Human expansion precipitates niche expansion for an opportunistic apex predator (Puma concolor) Wynne E. Moss1, Mathew W. Alldredge2, Kenneth A. Logan2 & Jonathan N. Pauli1 There is growing recognition that developed landscapes are important systems in which to promote ecological complexity and conservation. Yet, little is known about processes regulating these novel ecosystems, or behaviours employed by species adapting to them. We evaluated the isotopic niche of an apex carnivore, the cougar (Puma concolor), over broad spatiotemporal scales and in a region characterized by rapid landscape change. We detected a shift in resource use, from near complete specialization on native herbivores in wildlands to greater use of exotic and invasive species by cougars in contemporary urban interfaces. We show that 25 years ago, cougars inhabiting these same urban interfaces possessed diets that were intermediate. Thus, niche expansion followed human expansion over both time and space, indicating that an important top predator is interacting with prey in novel ways. Thus, though human-dominated landscapes can provide sufficient resources for apex carnivores, they do not necessarily preserve their ecological relationships. The conversion of wildlands to developed habitat is a pervasive threat to native species, and tends to create biotically homogenous communities1 differing strongly from their historical norm2. Though conservation efforts have traditionally focused on preserving pristine habitat, there is now growing interest in enhancing biodiversity in already transformed ecosystems (e.g. the “New Conservation” movement3), including human-dominated landscapes. Indeed, accumulating evidence suggests that urban ecosystems can represent viable habitat for species of conservation importance4. Yet, maintaining functional ecological relationships in these novel and transformed systems will be challenging, as they feature community assemblages and interactions that are entirely new and poorly understood2. Large-bodied carnivores have received disproportionate attention for their role as ecosystem regulators, and are often targeted as a means to restore stability to systems altered by human activity5. Until recently, it was assumed that only smaller-bodied mesocarnivores could exploit highly developed areas while large carnivores were excluded due to their sensitivity to fragmentation and enhanced conflict with humans6. After decades of decline, many large apex carnivores are rebounding in North America and Europe, and they are now increasingly using developed and urban habitats worldwide7–10. To understand the value and function of such ecosystems in global conservation, it is essential to measure how species at the highest trophic levels behave and exploit resources within them. Though much of our understanding of large carnivore ecology is derived from wildland systems, accumulating evidence suggests that habitat development significantly alters their behaviour and ecology in predictable ways. Due to shifts in prey communities, bottom-up subsidies, and altered risk landscapes in these emerging developed ecosystems, resource use of apex carnivores can differ strongly from historic patterns11. Dietary shifts, along with changes in demography12 have the potential to alter top-down forcing, with implications for ecosystem stability and resilience13. Thus, it has been suggested that apex carnivores in developed ecosystems are returning in name only, possessing a novel ecological niche14. Herein, we provide evidence that an ecologically important and rebounding apex carnivore15, the cougar (Puma concolor), has recently diversified its resource use and, therefore, is expanding its niche and 1 Department of Forest & Wildlife Ecology, University of Wisconsin, Madison, Wisconsin 53706, USA. 2Colorado Parks & Wildlife, Fort Collins, Colorado, 80525, USA. Correspondence and requests for materials should be addressed to W.E.M. (email: wmoss@wisc.edu) Scientific Reports | 6:39639 | DOI: 10.1038/srep39639 1 �www.nature.com/scientificreports/ Figure 1. Cougar niche varies with anthropogenic change. (a) Sites differed in land use (% of study area classified as developed; primary axis) and human density (secondary axis; for details see Supplementary Materials, Supplementary Table 1). (b) Estimates of diet (±​95% Bayesian credibility intervals) from mixing models revealed that the contemporary urban interface population had the lowest reliance on native herbivores, while the contemporary wildland population specialized almost entirely upon them. (c–e) Isotopic signatures of prey (plotted as corrected standard ellipses) from left to right: native herbivores, large domestic species, synanthropic wildlife, and small domestic species. Cougars (black dots) in the contemporary urban interface possessed the widest niche breadth (standard ellipse; in black). Cougars in the historic urban interface were isotopically distinct from their contemporary counterparts. interacting with novel prey in highly developed ecosystems. Traditionally viewed as wildland specialists reliant on tracts of protected land with high ungulate densities16,17, cougars are increasingly found utilizing a gradient of human-developed landscapes18–20. However, fundamental aspects of their ecology, including survival rates18,21 and diet21,22, appear to differ in highly developed landscapes. To understand how rapid and extensive this dietary shift is, and how cougar-prey interactions may change within these novel ecosystems, we analysed the isotopic signatures of three cougar populations in Colorado, USA: a contemporary wildland population, a contemporary population in an urban interface, and a population in that same urban interface 25 years prior. By modelling isotopic niche over broad spatiotemporal scales, we detected changes in resource use over space and time, including higher use of exotic and synanthropic prey in today’s urban interface. Over the past 25 years, cougar populations near human development expanded their diet, from near specialization on native herbivore prey to a more generalist diet. Thus, the interactions between cougars and their prey appear to shift in human-dominated landscapes, with implications for ecosystem functioning. Results Cougars from the three populations (contemporary urban interface, historic urban interface, and contemporary wildlands) differed in isotopic signature (K nearest-neighbour, p <​ 0.001; Fig. 1b–d; Supplementary Table 4). The contemporary urban interface population occupied a broader isotopic niche (SEAC =​  1.1; SEACB =​  1.1), compared to both the historic urban interface (SEAC =​  0.6; SEACB =​ 0.6) and wildland populations (SEAC =​  0.7; SEACB =​ 0.6), and these differences were significant (contemporary urban vs. wildland: p =​  0.03; contemporary urban vs. historic urban: p =​ 0.004; Supplementary Fig. 2). We did not detect a difference in isotopic niche size between cougars inhabiting the historic urban interface and wildlands (p =​ 0.44). Bootstrap analysis, as well as analyses of adults only, indicated that the patterns we observed were not driven by outliers, differences in sample sizes, or the demographic composition of samples (Supplementary Materials, Fig. S2, Table S5). Differences in isotopic niche reflected differences in resource use and dietary diversity between populations, as evidenced by population-wide diet estimates. Contemporary cougars in the urban interface used the highest diversity of prey, with 63–79% of their assimilated biomass from native herbivores (95% Bayesian credibility Scientific Reports | 6:39639 | DOI: 10.1038/srep39639 2 �www.nature.com/scientificreports/ intervals; Fig. 1e; Supplementary Table S4), and the rest from urban-associated food resources like domestic species (exotics) and synanthropic wildlife (invasives). The wildland population, conversely, relied almost entirely (91–99% of assimilated biomass) on native herbivores (Fig. 1e;), likely large ungulates like elk Cervus elaphus (Linnaeus 1758) and mule deer Odocoileus hemionus (Rafinesque 1817). We also observed temporal changes in diet; cougars in the urban interface in the 1980s were intermediate in use of native herbivores (Fig. 1e; 73–95% of diet). Discussion Cougars are opportunistic predators, and it appears that this plasticity could be one of the mechanisms by which they successfully exploit novel ecosystems. Indeed, we found that land use changes corresponded with shifts in dietary inputs and overall isotopic niche, and may indicate a changing ecology for cougars in these novel and developing landscapes. Cougars in the wildlands and those in the urban interface 25 years ago relied almost exclusively on native herbivores, principally large bodied ungulates. While still heavily reliant on native ungulates, cougars in the urban interface today interact with a more diverse group of prey species, including both exotic and invasive prey (synanthropic mesocarnivores and domestic species) which are abundant in developed habitats23. Though the land use change in the urban interface of Colorado’s Front Range over the past 25 years has primarily consisted of rural-to-exurban transformation (Supplementary Table S2), it appears this intensification of development is associated with large and rapid changes in diet composition for cougar inhabitants. Shifts in cougar diet over time and space may reflect differences in the availability of prey species, given the higher abundance of exotic and invasive prey in developed habitats23. However, there is evidence that cougars may actually select for smaller-bodied prey within developed landscapes to reduce handling time and thus risk22. It is highly unlikely, however, that the observed change in diet is simply due to changes in ungulate densities, which have remained relatively constant in the urban interface (Supplementary Materials, Figure S3). Regardless of whether shifts in resource use are due to increased availability of alternative prey or selection for smaller-bodied prey (or both), cougars have demonstrated a shift in resource use in developed areas, across both spatial and temporal scales. Although it is unclear whether this shift is repeated elsewhere, we anticipate this pattern holds true in other developed systems globally given the similarity of these areas regardless of geographic location1. The expansion in diet of cougars has a number of implications for both cougar conservation and the community dynamics of developed systems. For instance, the consumption of domestic species in developed landscapes enhances cougar mortality rates by increasing the risk of conflict with humans21, which could represent an ecological trap. Interactions with domestic and synanthropic prey, including closely related species (i.e. wild mesocarnivores and domestic cats and dogs), can also alter disease dynamics due to shared pathogens24,25. Finally, shifts in resource use by apex carnivores, even if the change is driven by a very few individuals, have the potential to alter the dynamics of prey populations, restructure community assemblages and transform ecosystem functioning26,27. It remains to be seen how the rapid changes in diet we have observed will affect the relationship between cougar and their ungulate prey, and is an interesting line of future research. Apex carnivores, which are important members of ecological communities, and are among the most threatened group of species on Earth, are less sensitive to habitat development than previously assumed, and are showing evidence of adaptation to human-dominated landscapes. Our work indicates that development intensification is associated with changes in resource use for one such apex carnivore over the course of only a few decades. Behavioural plasticity is an encouraging sign for carnivore conservation, but could also mean that these species are departing from their historic ecological relationships. Therefore, conserving or reintroducing species to novel urban landscapes will not necessarily resurrect historical ecological interactions, but may create novel ones instead. Methods Study sites. We evaluated resource use by contemporary (2008–2013) and historic (1983–1990) cougars in an urban interface, as well as contemporary (2008–2013) cougars in a wildland habitat. Within each site, we classified landcover using housing density28 and refer to urban, suburban, exurban, and rural lands as “developed” and protected, wildland habitat as “undeveloped”, though developed habitats vary widely in intensity and degree of ecological transformation. The wildland site, on the Uncompahgre Plateau of west-central Colorado, contains little developed habitat (6% of total land-cover), mostly along the perimeter of the study area, all of which constitutes low intensity exurban development (Fig. 1a; Supplementary Materials; Supplementary Table S1; Supplementary Fig. S1). The urban interface site, along the Northern Front Range of Colorado, is one of the major urban-wildland interfaces in the United States29. Urban and suburban habitat, which tend to be unsuitable for large carnivores, make up a small fraction (1%) of the study area. A sizeable proportion of the land area is exurban and rural (28% and 14%, respectively); this land use is of particular interest for cougar ecology, as the intermediate intensity of development provides attractive habitat for cougars, yet differs from wildland habitat in community composition and risk factors18. Over half (56%) of the urban interface site is undeveloped, and these undeveloped lands are patchy, occurring in close proximity with developed landscapes (Supplementary Fig. S1). Human density is 6×​greater than in the wildland site (Fig. 1a). In the 1980s, when historic cougars were sampled, this urban interface had 20% lower human density (Fig. 1a) and was intermediate in habitat development and human density (Supplementary Table S1). Interestingly, between 1980 and 2010, there was almost no conversion of undeveloped lands; rather, development on rural lands intensified, increasing exurban landcover (from 21 to 28%). Sampling and isotopic analysis. We collected contemporary samples from cougars during live captures or necropsies; we obtained historic samples from hunter mounts and museum specimens (Supplementary Materials). To estimate cougar diet and niche breadth, we analysed the isotopic signature of cougar and prey tissues in our Scientific Reports | 6:39639 | DOI: 10.1038/srep39639 3 �www.nature.com/scientificreports/ Group Native herbivores (urban interface) n Species 48 Cottontail rabbit (Sylvilagus nuttallii) δ13C δ15N −​21.8 ±​  1.0 7.2 ±​  2.0 −​21.5 ±​  0.4 8.5 ±​  1.1 −​19.9 ±​  1.4 10.3 ±​  1.6 −​18.0 ±​  1.3 10.8 ±​  1.4 −​14.0 ±​  2.5 9.6 ±​  1.3 Mule deer (Odocoileus hemionus) Elk (Cervus elaphus) Native herbivores (wildland) 15 Cottontail rabbit (Sylvilagus nuttallii) Mule deer (Odocoileus hemionus) Elk (Cervus elaphus) 26 Llama (Lama glama) Alpaca (Vicugna pacos) Large domestic species Goat (Capra aegagrus hircus) Sheep (Ovis aries) 38 Striped skunk (Mephitis mephitis) Raccoon (Procyon lotor) Fox (Vulpes vulpes) Synanthropic wildlife Coyote (Canis latrans) Squirrel (Sciurus spp.)* 29 Small domestic species Dog (Canis familiaris) Cat (Felis catus) Chicken (Gallus domesticus) Table 1. Isotopic signatures (x ± SD for potential prey of cougars (Puma concolor), collected between 2008 and 2013 in a wildland and an urban interface study area. Prey were grouped into isotopically distinct and biologically relevant groups and corrected using isotopic discrimination factors (δ​13C =​  +​2.6‰; δ​15N =​  +​3.4‰) so they could be directly compared to cougar signatures. Isotopic signatures for native herbivores differed between study sites. *Not identified to species level. study areas. Estimates obtained from stable isotopes are not biased towards larger-bodied prey30; and therefore can more accurately quantify dietary inputs and niche breadth. We have previously demonstrated21 that isotopic signature predicts both where cougars forage and what they forage upon, essential aspects (bionomic and scenopoetic) of a consumer’s occupied ecological niche31. Finally, isotopic analysis can be performed on non-invasively collected tissues, making comparisons over broad geographic or temporal scales more feasible. This approach, then, has the power to detect shifts in resource use and realized niche for cryptic, wide-ranging large carnivores at a scale that has previously been impossible. We captured and sampled hair from 58 adult and sub-adult cougars in the contemporary wildland site and 41 in the contemporary urban interface, from 2008 to 2013 (Supplementary Materials; Supplementary Table S2). All animal handling was in accordance with ACUC 16-2008 and 08-2004 approved by Colorado Parks & Wildlife, Fort Collins, CO. We also collected nine hair samples from the urban interface site between 1983 and 1990, using hunter mounts and museum specimens (Supplementary Materials, Supplementary Table S3). Finally, we collected hair from 17 potential prey species (Supplementary Materials). Hair samples were prepared using standard methods32 and analysed for carbon (δ​13C) and nitrogen (δ​15N) signature, reported as parts per thousand [‰] ratios relative to standards. We corrected for isotopic discrimination, the enrichment of heavy isotopes at higher trophic levels (Supplementary Materials). We grouped prey into isotopically distinct groups using K nearest-neighbour tests33. Prey clustered into four categories: native herbivores, synanthropic mesocarnivores, small domestic animals (pets), and large domestic animals (livestock), representing biologically meaningful classes (Table 1). To compare the isotopic niche of the three cougar populations, we computed corrected standard ellipse areas (SEAC) for each population34. Standard ellipses are bivariate estimates of variance in isotopic signature within a population and a useful metric for population-wide niche breadth. To compare ellipse areas between populations, we utilized a bootstrap approach (Supplementary Materials), which also allowed us to test the robustness of our estimates of SEAC to sample size and outliers. We report the median SEAC from bootstrap simulations (SEACB), as well as median p-values from t-tests (Supplementary Fig. S2). To interpret the ecological significance of isotopic niche shifts, we estimated population-wide diet compositions using Bayesian mixing models35,36. We report 95% credibility intervals of Bayesian posterior probability distributions, which represent the most likely proportion of each diet item for a given population of consumers. References 1. McKinney, M. L. Urbanization as a major cause of biotic homogenization. Biol. Conserv. 127, 247–260 (2006). 2. Hobbs, R. J. et al. Novel ecosystems : theoretical and management aspects of the new ecological world order. Glob. Ecol. Biogeogr. 15, 1–7 (2006). 3. Kareiva, P. & Marvier, M. What is conservation science? Bioscience 62, 962–969 (2012). 4. Baldock, K. C. R. et al. Where is the UK’s pollinator biodiversity? The importance of urban areas for flower- visiting insects. Proc. R. Soc. B Biol. Sci. 282, 20142849 (2015). 5. Ritchie, E. G. et al. Ecosystem restoration with teeth: What role for predators? Trends Ecol. Evol. 27, 265–271 (2012). 6. Prugh, L. R. et al. The Rise of the Mesopredator. Bioscience 59, 779–791 (2009). Scientific Reports | 6:39639 | DOI: 10.1038/srep39639 4 �www.nature.com/scientificreports/ 7. Athreya, V., Odden, M., Linnell, J. D. C., Krishnaswamy, J. & Karanth, U. Big cats in our backyards: persistence of large carnivores in a human dominated landscape in India. PLoS One 8, 2–9 (2013). 8. Dellinger, J. A., Proctor, C., Steury, T. D., Kelly, M. J. & Vaughan, M. R. Habitat selection of a large carnivore, the red wolf, in a human-altered landscape. Biol. Conserv. 157, 324–330 (2013). 9. Bouyer, Y. et al. Tolerance to anthropogenic disturbance by a large carnivore: the case of Eurasian lynx in south-eastern Norway. Anim. Conserv. 18, 271– 278 (2015). 10. Chapron, G. et al. Recovery of large carnivores in Europe’s modern human-dominated landscapes. Science. 346, 1517–1519 (2014). 11. Newsome, T. M. et al. Human-resource subsidies alter the dietary preferences of a mammalian top predator. Oecologia 175, 139–150 (2014). 12. Beckmann, J. P. & Berger, J. Rapid ecological and behavioural changes in carnivores: the responses of black bears (Ursus americanus) to altered food. J. Zool. 261, 207–212 (2003). 13. Rodewald, A. D., Kearns, L. J. & Shustack, D. P. Anthropogenic resource subsidies decouple predator-prey relationships. Ecol. Appl. 21, 936–43 (2011). 14. Ordiz, A., Bischof, R. & Swenson, J. E. Saving large carnivores, but losing the apex predator? Biol. Conserv. 168, 128–133 (2013). 15. Pierce, B. M., Bleich, V. C., Monteith, K. L. & Bowyer, R. T. Top-down versus bottom-up forcing: evidence from mountain lions and mule deer. J. Mammal. 93, 977–988 (2012). 16. Crooks, K. R. Relative Sensitivities of Mammalian Carnivores to Habitat Fragmentation. Conserv. Biol. 16, 488–502 (2002). 17. Beier, P., Riley, P. D. & Sauvajot, R. M. In Urban Carniv. Ecol. Conflict, Conserv. (Gehrt, S., Riley, S. & Cypher, B.) 177–189 (Johns Hopkins University Press, 2010). 18. Burdett, C. L. et al. Interfacing models of wildlife habitat and human development to predict the future distribution of puma habitat. Ecosphere 1, 1–21 (2010). 19. Kertson, B. N., Spencer, R. D., Marzluff, J. M., Hepinstall-Cymerman, J. & Grue, C. E. Cougar space use and movements in the wildland-urban landscape of western Washington. Ecol. Appl. 21, 2866–2881 (2011). 20. Wilmers, C. C. et al. Scale dependent behavioral responses to human development by a large predator, the puma. PLoS One 8, e60590 (2013). 21. Moss, W. E., Alldredge, M. W. & Pauli, J. N. Quantifying risk and resource use for a large carnivore in an expanding urban-wildland interface. J. Appl. Ecol. 53, 371–378 (2016). 22. Smith, J. A., Wang, Y. & Wilmers, C. C. Spatial characteristics of residential development shift large carnivore prey habits. J. Wildl. Manage. 80, 1040–1048 (2016). 23. Prange, S. & Gehrt, S. D. Changes in mesopredator-community structure in response to urbanization. Can. J. Zool. 82, 1804–1817 (2004). 24. Bevins, S. N. et al. Three pathogens in sympatric populations of pumas, bobcats, and domestic cats: Implications for infectious disease transmission. PLoS One 7, 1–10 (2012). 25. Foley, J. E. et al. Risk factors for exposure to feline pathogens in California mountain lions (Puma concolor). J. Wildl. Dis. 49, 279–93 (2013). 26. Estes, J. A., Tinker, M. T., Williams, T. M. & Doak, D. F. Killer whale predation on sea otters linking oceanic and nearshore ecosystems. Science. 282, 473–476 (1988). 27. Sweitzer, R. A., Jenkins, S. H. & Berger, J. Near-Extinction of Porcupines by Mountain Lions and Consequences of Ecosystem Change in the Great Basin Desert. Conserv. Biol. 11, 1407–1417 (2011). 28. Theobald, D. M. Landscape patterns of exurban growth in the USA from 1980 to 2020. Ecol. Soc. 10, 32 (2005). 29. Radeloff, V. et al. The wildland-urban interface in the United States. Ecol. Appl. 15, 799–805 (2005). 30. Kelly, J. F. Stable isotopes of carbon and nitrogen in the study of avian and mammalian trophic ecology. Can. J. Zool. 78, 1–27 (2000). 31. Hutchinson, G. E. An Introduction to Population Ecology. (Yale University Press, 1978). 32. Pauli, J. N., Ben-David, M., Buskirk, S. W., DePue, J. E. & Smith, W. P. An isotopic technique to mark mid-sized vertebrates noninvasively. J. Zool. 278, 141–148 (2009). 33. Rosing, M. N., Ben-David, M. & Barry, R. P. Analysis of stable isotope data: a K nearest-neighbors randomization test. J. Wildl. Manage. 62, 380–388 (1998). 34. Jackson, A. L., Inger, R., Parnell, A. C. & Bearhop, S. Comparing isotopic niche widths among and within communities: SIBER Stable Isotope Bayesian Ellipses in R. J. Anim. Ecol. 80, 595–602 (2011). 35. Parnell, A. C., Inger, R., Bearhop, S. & Jackson, A. L. Source partitioning using stable isotopes: coping with too much variation. PLoS One 5 (2010). 36. Parnell, A., Inger, R., Bearhop, S. & Jackson, A. L. SIAR: stable isotope analysis in R (2008). Acknowledgements This study was funded by Colorado Parks & Wildlife. Historic samples were obtained from the Museum of Southwestern Biology and from the Denver Museum of Nature & Science. We thank hunters, volunteers and technicians for help in obtaining samples. Author Contributions W.E.M. and J.N.P. wrote the manuscript and performed statistical analyses. W.E.M., J.N.P., and M.W.A. designed the study. W.E.M., M.W.A., and K.A.L. carried out field and laboratory analyses. All authors reviewed the manuscript. Additional Information Supplementary information accompanies this paper at http://www.nature.com/srep Competing financial interests: The authors declare no competing financial interests. How to cite this article: Moss, W. E. et al. Human expansion precipitates niche expansion for an opportunistic apex predator (​Puma concolor). Sci. Rep. 6, 39639; doi: 10.1038/srep39639 (2016). Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ © The Author(s) 2016 Scientific Reports | 6:39639 | DOI: 10.1038/srep39639 5 � https://cpw.cvlcollections.org/files/original/fbdbcbf8fe8a0b00a996910e339cca27.pdf 503564c38463b69acb27878307921ee1 PDF Text Text Niche expansion in an apex predator 1 Human expansion precipitates niche expansion for an opportunistic apex predator 2 (Puma concolor) 3 4 Wynne E. Moss1*, Mathew W. Alldredge2, Kenneth A. Logan2, and Jonathan N. Pauli1 5 6 1 7 Wisconsin 53706, USA 8 2 Department of Forest & Wildlife Ecology, University of Wisconsin, Madison, Colorado Parks & Wildlife, Fort Collins, Colorado, 80525, USA 9 10 *wmoss@wisc.edu �Niche expansion in an apex predator 11 SUPPLEMENTARY INFORMATION 12 Study areas 13 We conducted our study in two regions of Colorado, which represent extremes in human 14 influence. The wildland site, located in the Uncompahgre Plateau (Fig. S1), varies in 15 elevation from about 1,700 m to 3,000 m. The most abundant large herbivores in the 16 wildland study area are mule deer (Odocoileus hemionus) and elk (Cervus elaphus), 17 although sheep and cattle range within the study area during the summer months. Human 18 population density and road density are low, and over half of the land-cover is publicly 19 owned and undeveloped (Table S1). The urban interface site, located in the Northern 20 Front Range (Fig. S1), ranges from 1,600 to 4,300 m in elevation. The south-eastern part 21 of the urban interface site lies within the boundary of the expanding Denver metropolis, 22 while the south-western part of the study area is primarily publicly owned wildland; thus, 23 this study area is a matrix of both developed and undeveloped habitat (Table S1). We 24 sampled cougars within both of these study areas from 2008-2013, as well as cougars 25 living in the urban interface study area in the 1980s, which we refer to as the historic 26 urban interface. In the 1980s, there was 25% less developed habitat and 20% fewer 27 people in the urban interface study area, though the level of habitat development and 28 human density was still higher than observed in the wildland study area. Cougar density 29 in the wildland study site was at least 2.5 independent cougars per 100 km2;1, with 30 densities in the contemporary urban interface likely between 2 and 3 (Colorado Parks & 31 Wildlife unpublished data). 32 33 We quantified measures of anthropogenic influence within our study areas, as given by housing density, road density, and human population density. We obtained �Niche expansion in an apex predator 34 population counts at the census block group level in the contemporary sites2 and the 35 historic sites3. We selected all the census block groups whose centroid lay within the 36 bounds of the study site and summed their populations. Density was calculated by 37 dividing total population by the area of all selected census block groups. To determine 38 road density, we used TIGER/Line shapefiles4 to quantify the km of road per km2 study 39 area. 40 Housing density and land use categories for historic and contemporary study sites 41 were taken from the SERGoM model of housing density5; we used the 1990 historical 42 data layer for the historic urban interface study site and the projected 2010 layers for the 43 contemporary sites. We refer to exurban, suburban, or urban habitat (> 5 units/km2) as 44 “developed”. Undeveloped habitat contained no houses, while rural habitat was between 45 0.01 and 6 units/km2. 46 Finally, to determine if changes in ungulate density were driving changes in diet, 47 we examined mule deer population trends within the urban interface site from 1988 to 48 2010. Estimates of post-hunt population in the Boulder Creek deer herd (which overlaps 49 with the urban interface study area) were taken from Colorado Parks & Wildlife reports6. 50 Mule deer abundance and density did not change in the urban interface since the late 51 1980s (Fig. S3), therefore, differences in diet over time are unlikely to be the result of 52 changing ungulate availability. 53 Capture and isotopic sampling 54 Cougars in the wildland and urban interface site were captured and monitored from 2008- 55 2013 as part of a larger on-going study by Colorado Parks & Wildlife7,8. Sub-adult and 56 adult cougars were captured using dogs, cage traps, and snares, and immobilized with �Niche expansion in an apex predator 57 tiletamine hydrochloride (Telazol) or ketamine hydrochloride-medetomidine. Hair 58 samples for isotopic analysis were taken either at captures or necropsies (Table S2). All 59 animal handling was in accordance with ACUC 16-2008 and 08-2004 approved by 60 Colorado Parks & Wildlife, Fort Collins, CO. We searched state records for cougars 61 harvested within our study area between 1970 and 1990 and requested samples from 62 hunters. We also queried museum databases for samples within 50 km of our study area 63 prior to 1990 (Table S3). 64 We collected over 140 hair samples from over 15 prey species, which we 65 identified as being potentially important due to their prevalence at kill sites within our 66 study area or from previous studies of cougar diet9,10. Hair samples from wild prey 67 species were collected at cougar kill sites or road kills in both study areas. We sampled 68 domestic species in the wildland-urban study site using shed hairs from farms or 69 veterinary clinics, and assumed that domestic species would not vary geographically due 70 to a high reliance on commercial feed rather than wild plants. We did not sample prey 71 from the 1980s in the urban interface site, but assumed that prey isotopic signature did 72 not change over time. 73 74 Isotopic analysis 75 Hair samples from cougar and prey were rinsed in a 2:1 mixture of chloroform: methanol, 76 dried for 72 hours, and homogenized, following standard methods11. Samples were 77 analysed using a Carlo Erba 1100 Elemental Analyzer coupled to a Thermo Delta Plus 78 XP IRMS. Results are reported as parts per thousand [‰] ratios relative to international 79 standards of Peedee Belemnite (PDB; d13C) and atmospheric nitrogen (AIR; d15N). We �Niche expansion in an apex predator 80 adjusted prey isotopic signatures using isotopic correction factors for carnivores ( δ13C = 81 +2.6 ‰; δ15N = +3.4; 12). After correction, we grouped prey into biologically relevant and 82 isotopically distinct source groups using a K nearest-neighbour randomization test13. 83 Synanthropic wildlife from the wildland and urban interface sites did not differ (K 84 nearest-neighbour; p > 0.05); however, the native herbivore group differed in δ15N among 85 study areas (p < 0.01). Therefore, with the exception of the native herbivore group, we 86 used identical prey isotopic signatures in mixing models for all three populations. The 87 native herbivore group contains rabbits, elk, and deer, but, because ungulates are an order 88 of magnitude larger, use of this prey group reflects mostly consumption of ungulates, 89 rather than small mammals. 90 We corrected the d13C signatures of historic cougar samples to account for the 91 Suess effect, or the decrease in atmospheric 13C from fossil fuel burning14. We applied a - 92 0.022 ‰ per year correction15. To compare differences in raw isotopic signature between 93 cougar populations, we used K nearest-neighbour tests. 94 We computed a corrected standard ellipse (SEC) for each population in the 95 program SIAR16, with the area of each ellipse (SEAC) representing amount of isotopic 96 variation within a population. Compared with convex hull or standard deviation methods, 97 estimates of SEAC are more robust to differences in sample size and are, therefore, a 98 useful measure of niche breadth when sample sizes differ among groups, as in our 99 study17. 100 However, because standard ellipses are, themselves, estimates of uncertainty18, 101 the area of an ellipse does not have an associated variance estimate. In order to derive an 102 estimate of variance and test the robustness of SEAC estimates to sample sizes and �Niche expansion in an apex predator 103 outliers, we utilized a bootstrapping approach. First, given the small sample size of the 104 historic urban interface population (n = 9), we tested the sensitivity of SEAC estimates to 105 outliers. We calculated SEAC after excluding one sample, and repeated this nine times, 106 dropping a different sample each time. SEAC varied little, from 0.4 – 0.7, suggesting no 107 individual sample was overly influential (Fig. S2). Next, we used a similar process for the 108 contemporary urban and contemporary wildland datasets. Nine individuals were 109 randomly drawn from each sample set, and SEAC was estimated for those nine 110 individuals. We repeated this sampling nine times, to generate a distribution similar to the 111 one generated for the historic urban interface (Fig. S2). We compared each simulated 112 distribution with the historic urban interface distribution using a Welch’s t-test. We also 113 compared the contemporary wildland and contemporary urban distributions to one 114 another. We repeated this process 1000×, and calculated an average p-value and median 115 SEAC (Fig. S2). 116 Though SEAC provides a useful estimate of niche breadth, we could not directly 117 compare niche overlap (as measured by SEC overlap in bi-plots) between cougar 118 populations because the position of the SEC can be influenced by variation in prey 119 signature among groups, and may not necessarily reflect differences in foraging strategy 120 18 121 compare niche overlap independent of differences in the isotopic signature of prey, as in 122 Flaherty and Ben-David19. To estimate diet, SIAR uses Markov Chain Monte Carlo 123 simulations to generate a distribution of possible diets that are consistent with consumer 124 and prey isotopic signatures15. The output is given as Bayesian posterior distributions of 125 possible solutions20. We report diet as 95% Bayesian credibility intervals of these . Thus, we estimated diet compositions for populations in SIAR, which allowed us to �Niche expansion in an apex predator 126 distributions, which represents the most likely diet for an entire population. We grouped 127 small and large domestic species a posteriori because, though they differed isotopically, 128 the model could not accurately distinguish between these two sources. 129 Finally, to test whether differences between study areas were influenced by the 130 demographic composition of samples, we ran analyses using only adults from the two 131 contemporary populations. Because adults are more likely than subadults to consume 132 large-bodied native herbivores21, it is possible that differences in the demographic 133 structure of the three sample sets (Table S2) could influence estimates of native herbivore 134 use. Restricting the analysis to adults only in the contemporary population is the most 135 conservative approach, given that adults have the most ungulate specialized diets. We 136 retained subadults and unknown age individuals (n = 3) in the historic urban interface 137 population, because if anything, this would increase our estimate of alternative prey and 138 thus dietary breadth. With this new analysis, adults in the contemporary urban interface 139 still had broader isotopic niches and relied less on native herbivores than the historic 140 population (Table S5), and estimates of diet and niche breadth varied only slightly. 141 Similarly, restricting analyses to adults only in the wildland population also did not 142 change results significantly (Table S5). Thus, the patterns still held true, with isotopic 143 niche the largest and reliance on native herbivores the lowest in contemporary urban 144 interface cougars. Therefore, to maximize sample sizes and avoid confusion, we report 145 full results from analyses of the entire sample sets. �Niche expansion in an apex predator 146 �Niche expansion in an apex predator Tables Table S1. Measures of anthropogenic influence in Colorado study areas where we sampled cougars (Puma concolor). The wildland study site shows the lowest amount of anthropogenic influence and the contemporary urban interface study site the highest. In the 1980s, the urban interface site was intermediate for all measures of anthropogenic influence. Land use estimates and classifications were derived from the SERGoM model of housing density5 and are given as % area. Wildland Urban interface Urban interface (contemporary) (historic) (contemporary) Human density (persons/km2) 7 33 41 Road density (km roads/km2) 1.1 * 2.3 Undeveloped 72 58 56 Rural 22 19 14 Exurban 6 21 28 Suburban <1 1 1 Urban <1 <1 <1 Total area (km2) 2898 2869 2869 Land use (% total area) *Digitized maps of roads during the 1980s were not available for our study area. �Niche expansion in an apex predator Table S2. Age-sex classes of cougars sampled in contemporary wildland and urban interface study sites. Ages were determined using Logan’s21 criteria. Adults were individuals > 24 months who had established a home range and sub-adults were independent individuals < 24 months old. Study site Age-sex class N % of total sample Wildland Adult female 24 41 Adult male 11 19 Sub-adult female 9 16 Sub-adult male 14 24 Adult female 21 51 Adult male 7 17 Sub-adult female 7 17 Sub-adult male 6 15 Adult female 2 22 Adult male 4 44 Sub-adult (unknown sex) 1 11 Unknown 2 22 Contemporary urban interface Historic urban interface �Niche expansion in an apex predator Table S3. Historic samples collected from the urban interface study area in Colorado. Samples were obtained from museums or from mounts. We report accession numbers for museum samples. Source Mortality Age-sex class Year Mount Harvested Adult male 1983 Mount Harvested Adult male 1983 Mount Harvested Adult male 1986 Mount Roadkill Subadult 1989 Accession number female Mount Harvested Adult female 1986 Mount Harvested Adult male 1983 Denver Museum of Nature Unknown Unknown 1988 DMN ZM.7699 & Science Museum of Southwestern female Agency Adult female 1988 MSB:111939 Unknown Unknown 1990 MSB: 115606 Biology Museum of Southwestern Biology female �Niche expansion in an apex predator Table S4. Isotopic signatures and diet estimates for three cougar (Puma concolor) populations in Colorado. Dietary estimates are derived from Bayesian mixing models; we give the mean and 95% Bayesian credibility interval (CI) from simulations to estimate diet. The wildland population shows the highest reliance on native herbivores, followed by the historic urban interface population. The contemporary urban interface population relies most heavily upon alternative prey species. Isotopic signature: ! ± SD Dietary contribution: ! (95% CI) Native Domestic Synanthropic δ13C (‰) δ13N (‰) herbivores species wildlife Contemporary (2008-2013) 58 -21.6 ± 0.5 8.5 ± 0.5 96% (91-99%) 4% (1-8%) 1% (0-3%) Urban interface Historic (1983-1990) -21.6 ± 0.5 6.9 ± 0.6 85% (73-95%) 11% (1-21%) 5% (0-12%) Urban interface Contemporary (2008-2013) 41 -21.3 ± 0.65 8.1 ± 0.8 71% (63-79%) 23% (13-33%) 5% (0-12%) Study Area Time Wildland n 7 �Niche expansion in an apex predator Table S5. Results of analysis to test the impacts of demographic (i.e. subadult vs. adult) representation in samples. We restricted contemporary samples to adults only to enable direct comparisons of diet and niche breadth, and to reduce possible effects of differences in demographic structure of samples. We compared contemporary adult cougars to the full sample of historic cougars, which included subadult individuals. Our analysis demonstrated that patterns of niche expansion and dietary shifts were robust to the demographic classes sampled. Full population analysis Adults-only analysis Dietary contribution Isotopic niche Dietary contribution from Isotopic niche from native herbivores* (SEAC) native herbivores* (SEAC) Contemporary urban interface 63–79% 1.1 65–84% 1.0 Contemporary wildland 84–98% 0.7 91–99% 0.6 Historic urban interface 73–95% 0.6 N/A N/A Population *95% Bayesian credibility interval �Niche expansion in an apex predator Figures 2 Housing density (units/km ) 2400 (urban) Wildland Wildland (contemporary) (contemporary) ! P Delta 300 (suburban) 40 (exurban) ! P ! P Nucla ! P 5 (rural) 0 (undeveloped) Highways 0 10 20 Montrose Norwood Ridgway ! P Urban-wildland Urban interface (historic) (historic) 40 Km ! P Lyons Urban-wildland Urban interface (contemporary) (contemporary) ! P Boulder ! P Boulder P Idaho Springs ! ¯ Evergreen ! P ! P Golden ! PMorrison ! P Lyons P Idaho Springs ! Evergreen ! P ! P Golden ! P Morrison Figure S1. Study areas in Colorado, where we sampled cougars (Puma concolor) for isotopic analysis. The wildland study site, which was sampled from 2008 – 2013, is located on the Uncompahgre Plateau of west-central Colorado, which has little anthropogenic influence. The Northern Front Range of Colorado is an expanding urbanwildland interface; we sampled this site in the 1980s (urban interface historic) and from 2008-2013 (urban interface contemporary). Housing density is classified with SERGoM housing density raster layers5 using 2010 data for contemporary land use and 1990 data for historic land use. Maps were created using ArcGIS software and base maps (Version 10.2, Esri, www.esri.com). �Niche expansion in an apex predator Figure S2. Bootstrapped comparison of SEAC (corrected standard ellipse areas) between cougar (Puma concolor) populations. For the contemporary urban interface and wildland populations, we randomly drew nine individuals from the larger sample set and calculated SEAC; this was repeated nine times to give a distribution of SEAC estimates (a single thin line). We repeated this 1000 times and plotted the median distribution (heavy line). For the historic urban interface population (n =9), we randomly dropped one sample and calculated SEAC for the remaining samples, and repeated this for all possible combinations, giving one distribution (in red). Non-bootstrapped estimates of SEAC (dashed lines) are also shown. �Niche expansion in an apex predator 10000 Post-hunt population estimate 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 Figure S3. Estimates of population size for the deer herd in the Boulder Creek Deer Herd management unit . The urban interface study area is located within this management unit. Estiamtes are modeled post-hunt populations, gathered by Colorado Parks & Wildlife6. Deer abundance was near 8000 for both historic (1980s) and contemporary (2007-2013) sampling periods, although pre-1988 estimates were not available. �Niche expansion in an apex predator References 1. Logan, K. A. Puma population structure and vital rates on the Uncompahgre Plateau. Annual Report, Mammals Program, Colorado Division of Parks and Wildlife (2013). 2. United States Census Bureau. Census of population and housing: summary tape file 1 on CD ROM (Colorado). (2010). https://www.nhgis.org. 3. United States Census Bureau. Census of population and housing: summary tape file 1 on CD ROM (Colorado). (1990). https://www.nhgis.org. 4. United States Census Bureau. TIGER/Line Mapping Service: Colorado state. (2010). www.census.gov/geo/maps-data/data/tiger-line.html. 5. Theobald, D. M. Landscape patterns of exurban growth in the USA from 1980 to 2020. Ecol. Soc. 10, 32 (2005). 6. Huwer, S. & Kraft, B. D-27 Boulder Creek deer herd management plan. Colorado Parks and Wildlife (2012). 7. Alldredge, M. W. Cougar demographics and human interactions along the urbanexurban Front-Range of Colorado. Annual Report, Mammals Research, Colorado Parks and Wildlife (2011). 8. Logan, K. A. Puma population structure and vital rates on the Uncompahgre Plateau. Annual Report, Mammals Research, Colorado Parks and Wildlife (2009). 9. Kertson, B. N., Spencer, R. D. & Grue, C. E. Cougar prey use in a wildland–urban environment in western Washington. Northwest. Nat. 92, 175–185 (2011). 10. Knopff, K. H., Knopff, A. A., Kortello, A. & Boyce, M. S. Cougar kill rate and prey composition in a multiprey system. J. Wildl. Manage. 74, 1435–1447 (2010). 11. Pauli, J. N., Ben-David, M., Buskirk, S. W., DePue, J. E. & Smith, W. P. An isotopic technique to mark mid-sized vertebrates non-invasively. J. Zool. 278, 141–148 (2009). 12. Roth, J. D. & Hobson, K. A. Stable carbon and nitrogen isotopic fractionation between diet and tissue of captive red fox: implications for dietary reconstruction. Can. J. Zool. 78, 848–852 (2000). 13. Rosing, M. N., Ben-David, M. & Barry, R. P. Analysis of stable isotope data: a K nearest-neighbors randomization test. J. Wildl. Manage. 62, 380–388 (1998). �Niche expansion in an apex predator 14. Sonnerup, R. E. et al. Reconstructing the oceanic 13C Suess Effect. Global Biogeochem. Cycles 13, 857–872 (1999). 15. Hopkins, J. B. & Ferguson, J. M. Estimating the diets of animals using stable isotopes and a comprehensive Bayesian mixing model. PLoS One 7, e28478 (2012). 16. Parnell, A., Inger, R., Bearhop, S. & Jackson, A. L. SIAR: stable isotope analysis in R. (2008). 17. Jackson, A. L., Inger, R., Parnell, A. C. & Bearhop, S. Comparing isotopic niche widths among and within communities: SIBER - Stable Isotope Bayesian Ellipses in R. J. Anim. Ecol. 80, 595–602 (2011). 18. Newsome, S. D., del Rio, C. M., Bearhop, S. & Phillips, D. L. A niche for isotopic ecology. Front. Ecol. Environ. 5, 429–436 (2007). 19. Flaherty, E. A. & Ben-David, M. Overlap and partitioning of the ecological and isotopic niches. Oikos 119, 1409–1416 (2010). 20. Parnell, A. C., Inger, R., Bearhop, S. & Jackson, A. L. Source Partitioning Using Stable Isotopes: Coping with Too Much Variation. PLoS One 5, (2010). 20. Moss, W. E., Alldredge, M. W. & Pauli, J. N. Quantifying risk and resource use for a large carnivore in an expanding urban–wildland interface. J Appl Ecol 53, 371–378 (2016). 21. Logan, K. A. & Sweanor, L. L. Desert puma: evolutionary ecology and conservation of an enduring carnivore. (Island Press, 2001). � Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Journal Articles Description An account of the resource CPW peer-reviewed journal publications Text A resource consisting primarily of words for reading. Examples include books, letters, dissertations, poems, newspapers, articles, archives of mailing lists. Note that facsimiles or images of texts are still of the genre Text. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Human expansion precipitates niche expansion for an opportunistic apex predator (<em>Puma concolor</em>) Description An account of the resource <span>There is growing recognition that developed landscapes are important systems in which to promote ecological complexity and conservation. Yet, little is known about processes regulating these novel ecosystems, or behaviours employed by species adapting to them. We evaluated the isotopic niche of an apex carnivore, the cougar (</span><i>Puma concolor</i><span>), over broad spatiotemporal scales and in a region characterized by rapid landscape change. We detected a shift in resource use, from near complete specialization on native herbivores in wildlands to greater use of exotic and invasive species by cougars in contemporary urban interfaces. We show that 25 years ago, cougars inhabiting these same urban interfaces possessed diets that were intermediate. Thus, niche expansion followed human expansion over both time and space, indicating that an important top predator is interacting with prey in novel ways. Thus, though human-dominated landscapes can provide sufficient resources for apex carnivores, they do not necessarily preserve their ecological relationships.</span> Bibliographic Citation A bibliographic reference for the resource. Recommended practice is to include sufficient bibliographic detail to identify the resource as unambiguously as possible. <p>Moss, W. E., M. W. Alldredge, K. A. Logan, and J. N. Pauli. 2016. Human expansion precipitates niche expansion for an opportunistic apex predator (Puma concolor). Scientific Reports 6:<span>39639</span>. <a href="https://doi.org/10.1038/srep39639" target="_blank" rel="noreferrer noopener">https://doi.org/10.1038/srep39639</a></p> Creator An entity primarily responsible for making the resource Moss, Wynne E. Alldredge, Mathew W. Logan, Kenneth A. Pauli, Jonathan N. Subject The topic of the resource Animal behaviour Conservation biology Stable isotope analysis Extent The size or duration of the resource. 5 pages Date Created Date of creation of the resource. 2016-12-23 Rights Information about rights held in and over the resource <a href="http://rightsstatements.org/vocab/InC-NC/1.0/" target="_blank" rel="noreferrer noopener">In Copyright - Non-Commercial Use Permitted</a> <a href="https://creativecommons.org/licenses/by-nc/4.0/" target="_blank" rel="noreferrer noopener">Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)</a> Format The file format, physical medium, or dimensions of the resource application/pdf Language A language of the resource English Is Part Of A related resource in which the described resource is physically or logically included. Scientific Reports Type The nature or genre of the resource Article