1
|
Pahl CC, Ruedas LA. Big boned: How fat storage and other adaptations influenced large theropod foraging ecology. PLoS One 2023; 18:e0290459. [PMID: 37910492 PMCID: PMC10619836 DOI: 10.1371/journal.pone.0290459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 08/08/2023] [Indexed: 11/03/2023] Open
Abstract
Dinosaur foraging ecology has been the subject of scientific interest for decades, yet much of what we understand about it remains hypothetical. We wrote an agent-based model (ABM) to simulate meat energy sources present in dinosaur environments, including carcasses of giant sauropods, along with living, huntable prey. Theropod dinosaurs modeled in this environment (specifically allosauroids, and more particularly, Allosaurus Marsh, 1877) were instantiated with heritable traits favorable to either hunting success or scavenging success. If hunter phenotypes were more reproductively successful, their traits were propagated into the population through their offspring, resulting in predator specialists. If selective pressure favored scavenger phenotypes, the population would evolve to acquire most of their calories from carrion. Data generated from this model strongly suggest that theropods in sauropod-dominated systems evolved to detect carcasses, consume and store large quantities of fat, and dominate carcass sites. Broadly speaking, selective forces did not favor predatory adaptations, because sauropod carrion resource pools, as we modeled them, were too profitable for prey-based resource pools to be significant. This is the first research to test selective pressure patterns in dinosaurs, and the first to estimate theropod mass based on metabolic constraints.
Collapse
Affiliation(s)
- Cameron C. Pahl
- Department of Biology and Museum of Vertebrate Biology, Science Research and Teaching Center—246, Portland State University, Portland, Oregon, United States of America
| | - Luis A. Ruedas
- Department of Biology and Museum of Vertebrate Biology, Science Research and Teaching Center—246, Portland State University, Portland, Oregon, United States of America
| |
Collapse
|
2
|
Farlow JO, Coroian D, Currie PJ, Foster JR, Mallon JC, Therrien F. "Dragons" on the landscape: Modeling the abundance of large carnivorous dinosaurs of the Upper Jurassic Morrison Formation (USA) and the Upper Cretaceous Dinosaur Park Formation (Canada). Anat Rec (Hoboken) 2023; 306:1669-1696. [PMID: 35815600 DOI: 10.1002/ar.25024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/20/2022] [Accepted: 06/13/2022] [Indexed: 11/09/2022]
Abstract
Counts of the number of skeletal specimens of "adult" megaherbivores and large theropods from the Morrison and Dinosaur Park formations-if not biased by taphonomic artifacts-suggest that the big meat-eaters were more abundant, relative to the number of big plant-eaters, than one would expect on the basis of the relative abundance of large carnivores and herbivores in modern mammalian faunas. Models of megaherbivore population density (number of individuals per square kilometer) that attempt to take into account ecosystem productivity, the size structure of megaherbivore populations, and individual megaherbivore energy requirements, when combined with values of the large theropod/megaherbivore abundance ratio, suggest that large theropods may have been more abundant on the landscape than estimates extrapolated from the population density versus body mass relationship of mammalian carnivores. Models of the meat production of megaherbivore populations and the meat requirements of "adult" large theropods suggest that herbivore productivity would have been insufficient to support the associated number of individuals of "adult" large theropods, unless the herbivore production/biomass ratio was substantially higher, and/or the large theropod meat requirement markedly lower, than expectations based on modern mammals. Alternatively, or in addition to one or both of these other factors, large theropods likely included dinosaurs other than megaherbivores as significant components of their diet.
Collapse
Affiliation(s)
- James O Farlow
- Department of Biological Sciences, Purdue University, Fort Wayne, Indiana, USA
| | - Dan Coroian
- Department of Mathematical Sciences, Purdue University Fort Wayne, Fort Wayne, Indiana, USA
| | - Philip J Currie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - John R Foster
- Utah Field House of Natural History State Park, Vernal, Utah, USA
| | - Jordan C Mallon
- Beaty Centre for Species Discovery and Palaeobiology Section, Canadian Museum of Nature, Ottawa, Ontario, Canada
- Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
| | | |
Collapse
|
3
|
Forth G. Surviving Dragons: Ethnographic Reports of Komodo Monitors (Varanus komodoensis) in Northeastern Flores. J ETHNOBIOL 2022. [DOI: 10.2993/0278-0771-42.4.417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Gregory Forth
- Professor Emeritus, Department of Anthropology, University of Alberta, Edmonton, Alberta, Canada T6G 2H4
| |
Collapse
|
4
|
Purwandana D, Ariefiandy A, Azmi M, Nasu SA, Sahudin, Dos AA, Jessop TS. Turning ghosts into dragons: improving camera monitoring outcomes for a cryptic low-density Komodo dragon population in eastern Indonesia. WILDLIFE RESEARCH 2021. [DOI: 10.1071/wr21057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract Context Detection probability is a key attribute influencing population-level wildlife estimates necessary for conservation inference. Increasingly, camera traps are used to monitor threatened reptile populations and communities. Komodo dragon (Varanus komodoensis) populations have been previously monitored using camera traps; however, considerations for improving detection probability estimates for very low-density populations have not been well investigated. Aims Here we compare the effects of baited versus non-baited camera monitoring protocols to influence Komodo dragon detection and occupancy estimates alongside monitoring survey design and cost considerations for ongoing population monitoring within the Wae Wuul Nature Reserve on Flores Island, Indonesia. Methods Twenty-six camera monitoring stations (CMS) were deployed throughout the study area with a minimum of 400 m among CMS to achieve independent sampling units. Each CMS was randomly assigned as a baited or non-baited camera monitoring station and deployed for 6 or 30 daily sampling events. Key results Baited camera monitoring produced higher site occupancy estimates with reduced variance. Komodo dragon detection probability estimates were 0.15 ± 0.092–0.22 (95% CI), 0.01 ± 0.001–0.03, and 0.03 ± 0.01–0.04 for baited (6 daily survey sampling events), unbaited (6 daily survey sampling events) and long-unbaited (30 daily survey sampling events) sampling durations respectively. Additionally, the provision of baited lures at cameras had additional benefits for Komodo detection, survey design and sampling effort costs. Conclusions Our study indicated that baited cameras provide the most effective monitoring method to survey low-density Komodo dragon populations in protected areas on Flores. Implications We believe our monitoring approach now lends itself to evaluating population responses to ecological and anthropogenic factors, hence informing conservation efforts in this nature reserve.
Collapse
|
5
|
Jessop TS, Holmes B, Sendjojo A, Thorpe MO, Ritchie EG. Assessing the benefits of integrated introduced predator management for recovery of native predators. Restor Ecol 2021. [DOI: 10.1111/rec.13419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tim S. Jessop
- Centre for Integrative Ecology, School of Life and Environmental Sciences Deakin University Geelong Victoria 3216 Australia
| | - Ben Holmes
- Wimmera Catchment Management Authority Horsham Victoria 3400 Australia
| | - Arvel Sendjojo
- Centre for Integrative Ecology, School of Life and Environmental Sciences Deakin University Geelong Victoria 3216 Australia
| | - Mary O. Thorpe
- Centre for Integrative Ecology, School of Life and Environmental Sciences Deakin University Geelong Victoria 3216 Australia
| | - Euan G. Ritchie
- Centre for Integrative Ecology, School of Life and Environmental Sciences Deakin University Geelong Victoria 3216 Australia
| |
Collapse
|
6
|
Ariefiandy A, Purwandana D, Azmi M, Panggur MR, Mardani J, Parra DP, Jessop TS. Invasive water buffalo population trends and competition-related consequences for native rusa deer in eastern Indonesian protected areas. Mamm Biol 2021. [DOI: 10.1007/s42991-021-00161-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
7
|
Abstract
Many large predators are also facultative scavengers that may compete with and depredate other species at carcasses. Yet, the ecological impacts of facultative scavenging by large predators, or their "scavenging effects," still receive relatively little attention in comparison to their predation effects. To address this knowledge gap, we comprehensively examine the roles played by, and impacts of, facultative scavengers, with a focus on large canids: the African wild dog (Lycaon pictus), dhole (Cuon alpinus), dingo (Canis dingo), Ethiopian wolf (Canis simensis), gray wolf (Canis lupus), maned wolf (Chrysocyon brachyurus), and red wolf (Canis rufus). Specifically, after defining facultative scavenging as use or usurpation of a carcass that a consumer has not killed, we (1) provide a conceptual overview of the community interactions around carcasses that can be initiated by facultative scavengers, (2) review the extent of scavenging by and the evidence for scavenging effects of large canids, (3) discuss external factors that may diminish or enhance the effects of large canids as scavengers, and (4) identify aspects of this phenomenon that require additional research attention as a guide for future work.
Collapse
Affiliation(s)
- Aaron J Wirsing
- School of Environment and Forest Sciences, University of Washington, Seattle, WA 98195, USA
| | - Thomas M Newsome
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| |
Collapse
|
8
|
Lincoln A, Wirsing A, Quinn T. Prevalence and patterns of scavenging by brown bears ( Ursus arctos) on salmon ( Oncorhynchus spp.) carcasses. CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Scavenging, an underappreciated mechanism of prey consumption for many predators, can contribute substantially to nutritional intake. Facultative scavengers such as brown bears (Ursus arctos Linnaeus, 1758) may both kill and scavenge Pacific salmon (genus Oncorhynchus Suckley, 1861), though the extent of scavenging and factors affecting this behavior are unclear. We tagged 899 sockeye salmon (Oncorhynchus nerka (Walbaum in Artedi, 1792)) carcasses and placed them on streambanks over 5 years at multiple sites in southwestern Alaska (USA) where brown bears annually prey on spawning sockeye salmon. Examination of carcasses revealed overall scavenging rates of 15% after 1 day and 54% after 3 days. Scavenging rate varied by site and year and increased throughout the salmon run. Contrary to predictions, scavenging was more frequent in senescent or bear-killed carcasses than ripe carcasses. Carcass consumption ranged from minimal to almost complete; body and brain tissues were most frequently consumed after 3 days (68% and 63% of carcasses, respectively). We also documented secondary scavenging (i.e., tissue consumption on two separate events) and delayed scavenging (i.e., scavenging observed after 3 days but not 1 day). Taken together, the results indicated that scavenging in these streams contributes significantly to total consumption of salmon by bears, with ramifications for other components of these salmon-dependent ecosystems.
Collapse
Affiliation(s)
- A.E. Lincoln
- School of Aquatic and Fishery Sciences, University of Washington, 1122 NE Boat Street, Seattle, WA 98195, USA
| | - A.J. Wirsing
- School of Environmental and Forest Sciences, University of Washington, 4000 15th Avenue NE, Seattle, WA 98195, USA
| | - T.P. Quinn
- School of Aquatic and Fishery Sciences, University of Washington, 1122 NE Boat Street, Seattle, WA 98195, USA
| |
Collapse
|
9
|
Putman BJ, Tippie ZA. Big City Living: A Global Meta-Analysis Reveals Positive Impact of Urbanization on Body Size in Lizards. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.580745] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Urban environments pose different selective pressures than natural ones, leading to changes in animal behavior, physiology, and morphology. Understanding how animals respond to urbanization could inform the management of urban habitats. Non-avian reptiles have important roles in ecosystems worldwide, yet their responses to urbanization have not been as comprehensively studied as those of mammals and birds. However, unlike mammals and birds, most reptiles cannot easily move away from disturbances, making the selective pressure to adapt to urban environments especially strong. In recent years, there has been a surge in research on the responses of lizards to urbanization, yet no formal synthesis has determined what makes an urban lizard, in other words, which phenotypic traits are most likely to change with urbanization and in which direction? Here, we present a qualitative synthesis of the literature and a quantitative phylogenetic meta-analysis comparing phenotypic traits between urban and non-urban lizard populations. The most robust finding from our analysis is that urban lizards are larger than their non-urban counterparts. This result remained consistent between sexes and taxonomic groups. Hence, lizards that pass through the urban filter have access to better resources, more time for foraging, and/or there is selection on attaining a larger body size. Other results included an increase in the diameters of perches used and longer limb and digit lengths, although this may be a result of increased body size. Urban lizards were not bolder, more active or exploratory, and did not differ in immune responses than non-urban populations. Overall, studies are biased to a few geographic regions and taxa. More than 70% of all data came from three species of anoles in the family Dactyloidae, making it difficult to generalize patterns to other clades. Thus, more studies are needed across multiple taxa and habitats to produce meaningful predictions that could help inform conservation and management of urban ecological communities.
Collapse
|