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Ungulates and Their Impact on Reptiles: A Review of Interspecific Relationships. DIVERSITY 2022. [DOI: 10.3390/d15010028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Several ungulate species are showing increasing population patterns within their geographical distribution ranges, leading to constant interactions with other animal species. Varying densities and activities of different ungulates may result in diverse impacts on other coexisting species groups, including large numbers of threatened species, such as reptiles. In this study, we performed an analysis of the available literature to investigate the impacts of ungulates on reptiles. We aimed to reveal the diversity of: (1) the geographical and environmental distribution of related investigations; (2) the ungulate and reptile species involved; and (3) the characteristics of interactions (direct or indirect, positive or negative) from 69 publications. Our results show that the most papers were reported from the Americas (42%) and Australia (28%). The proportions of studies were balanced for wild ungulates (53%) and livestock (47%). Wild boar (Sus scrofa) was found to be the most problematic species on reptiles whereas reptiles which suffered the harshest impacts were Squamates (i.e., lizards, and snakes). Ungulate activities (e.g., digging by wild boar) may directly harm reptiles (consuming or killing them) or indirectly affect them by modifying their habitats or destroying their hideouts. Some preferential effects were also noted (e.g., by moderate livestock grazing or when wild ungulates are prey for large reptiles). Published livestock impacts were mainly indirect and mostly negatively linked to overgrazing. We conclude that it is important to manage and monitor the densities of ungulates to minimize their negative impacts on reptile species, especially in case of wild boar and grazing livestock, but also to maintain their moderate beneficial effects (e.g., as prey basis).
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Complementary Differences in Primary Production and Phenology among Vegetation Types Increase Ecosystem Resilience to Climate Change and Grazing Pressure in an Iconic Mediterranean Ecosystem. REMOTE SENSING 2021. [DOI: 10.3390/rs13193920] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Plant primary production is a key factor in ecosystem dynamics. In environments with high climatic variability such as the Mediterranean region, plant primary production shows strong seasonal and inter-annual fluctuations, which both drive and interplay with herbivore grazing. Knowledge on the responses of different vegetation types to the variability in both rainfall and grazing pressure by wild and domestic ungulates is a necessary starting point for the sustainable management of these ecosystems. In this work we combine a 15 year series of remote sensing data on plant production (NDVI) with meteorological (daily precipitation data) and ungulate abundance (annual counts of four species of wild and domestic ungulates: red deer, fallow deer, cattle, and horses) in an iconic protected area (the Doñana National Park, SW Spain) to (i) estimate the impact of intra- and inter-annual variation in rainfall and herbivore pressure on primary production, for each of four main vegetation types; and (ii) evaluate the potential impact of different policy (i.e., herbivore management) strategies under expected climate change scenarios. Our results show that the production of different vegetation types differed strongly in their responses to phenology (a surrogate of the effect of climatology on vegetation development), water availability (rainfall accumulated until the phenological peak), and grazing pressure. Although the density of domestic ungulates shows a linear, negative effect on the primary production of three of the four vegetation types, differences in primary production and phenology among vegetation types increase ecosystem resilience to both climatological variability and grazing pressure. Such resilience may, however, be reduced under the conditions predicted by climate change models, if the moderate predicted reduction in rainfall levels combines with moderate to high densities of domestic ungulates, resulting in important reductions in primary production that may compromise plant regeneration, leading to irreversible degradation. New management strategies taking advantage of habitat heterogeneity and phenological alternation, more flexible stocking rates, and the redistribution of management units should be considered to mitigate these effects. The use of available remote sensing data and techniques in combination with statistical models represents a valuable tool for developing, monitoring, and refining such strategies.
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Johnson BK, Jackson DH, Cook RC, Clark DA, Coe PK, Cook JG, Rearden SN, Findholt SL, Noyes JH. Roles of maternal condition and predation in survival of juvenile Elk in Oregon. WILDLIFE MONOGRAPHS 2019. [DOI: 10.1002/wmon.1039] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Bruce K. Johnson
- Oregon Department of Fish and Wildlife; 1401 Gekeler Lane La Grande OR 97850 USA
| | - Dewaine H. Jackson
- Oregon Department of Fish and Wildlife; 4192 N. Umpqua Highway Roseburg OR 97470 USA
| | - Rachel C. Cook
- National Council for Air and Stream Improvement; 1401 Gekeler Lane La Grande OR 97850 USA
| | - Darren A. Clark
- Oregon Department of Fish and Wildlife; 1401 Gekeler Lane La Grande OR 97850 USA
| | - Priscilla K. Coe
- Oregon Department of Fish and Wildlife; 1401 Gekeler Lane La Grande OR 97850 USA
| | - John G. Cook
- National Council for Air and Stream Improvement; 1401 Gekeler Lane La Grande OR 97850 USA
| | - Spencer N. Rearden
- Oregon Cooperative Fish and Wildlife Research Unit; Oregon State University; Corvallis OR 97331 USA
| | - Scott L. Findholt
- Oregon Department of Fish and Wildlife; 1401 Gekeler Lane La Grande OR 97850 USA
| | - James H. Noyes
- Oregon Department of Fish and Wildlife; 1401 Gekeler Lane La Grande OR 97850 USA
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De Jager NR, Rohweder JJ, Miranda BR, Sturtevant BR, Fox TJ, Romanski MC. Modelling moose-forest interactions under different predation scenarios at Isle Royale National Park, USA. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2017; 27:1317-1337. [PMID: 28263421 DOI: 10.1002/eap.1526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/16/2017] [Accepted: 02/06/2017] [Indexed: 06/06/2023]
Abstract
Loss of top predators may contribute to high ungulate population densities and chronic over-browsing of forest ecosystems. However, spatial and temporal variability in the strength of interactions between predators and ungulates occurs over scales that are much shorter than the scales over which forest communities change, making it difficult to characterize trophic cascades in forest ecosystems. We applied the LANDIS-II forest succession model and a recently developed ungulate browsing extension to model how the moose population could interact with the forest ecosystem of Isle Royale National Park, USA, under three different wolf predation scenarios. We contrasted a 100-yr future without wolves (no predation) with two predation scenarios (weak, long-term average predation rates and strong, higher than average rates). Increasing predation rates led to lower peak moose population densities, lower biomass removal rates, and higher estimates of forage availability and landscape carrying capacity, especially during the first 40 yr of simulations. Thereafter, moose population density was similar for all predation scenarios, but available forage biomass and the carrying capacity of the landscape continued to diverge among predation scenarios. Changes in total aboveground live biomass and species composition were most pronounced in the no predation and weak predation scenarios. Consistent with smaller-scale studies, high browsing rates led to reductions in the biomass of heavily browsed Populus tremuloides, Betula papyrifera, and Abies balsamea, and increases in the biomass of unbrowsed Picea glauca and Picea mariana, especially after the simulation year 2050, when existing boreal hardwood stands at Isle Royale are projected to senesce. As a consequence, lower predation rates corresponded with a landscape that progressively shifted toward dominance by Picea glauca and Picea mariana, and lacking available forage biomass. Consistencies with previously documented small-scale successional shifts, and population estimates and trends that approximate those from this and other boreal forests that support moose provide some confidence that these dynamics represent a trophic cascade and therefore provide an important baseline against which to evaluate long-term and large-scale effects of alternative predator management strategies on ungulate populations and forest succession.
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Affiliation(s)
- Nathan R De Jager
- U.S. Geological Survey Upper Midwest Environmental Sciences Center, La Crosse, Wisconsin, 54603, USA
| | - Jason J Rohweder
- U.S. Geological Survey Upper Midwest Environmental Sciences Center, La Crosse, Wisconsin, 54603, USA
| | - Brian R Miranda
- Institute for Applied Ecosystem Studies, Northern Research Station, USDA Forest Service, Rhinelander, Wisconsin, 54501, USA
| | - Brian R Sturtevant
- Institute for Applied Ecosystem Studies, Northern Research Station, USDA Forest Service, Rhinelander, Wisconsin, 54501, USA
| | - Timothy J Fox
- U.S. Geological Survey Upper Midwest Environmental Sciences Center, La Crosse, Wisconsin, 54603, USA
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Hudson RJ, Jeon BT. Are nutritional adaptations of wild deer relevant to commercial venison production$. ECOSCIENCE 2016. [DOI: 10.1080/11956860.2003.11682794] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Bison with benefits: towards integrating wildlife and ranching sectors on a public rangeland in the western USA. ORYX 2015. [DOI: 10.1017/s0030605314001197] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AbstractThe North American model of wildlife conservation, based on the public trust doctrine, is credited for the recovery of several charismatic wildlife species, including the plains bison Bison bison. In that model, wildlife is a public resource from which the private sector may not profit either individually or collectively. In recent years, however, resilience thinking is driving changes in the traditional state-run wildlife management model to allow for integrated multi-sector approaches at the landscape scale. A free-ranging herd of bison on public land in the Henry Mountains of Utah is used as a case study to consider if and how a community-based conservation programme could be developed for a state-managed wildlife resource to benefit all stakeholders. The Henry Mountains bison, which are disease-free, share the rangeland with cattle that are privately owned by individual ranchers and corporations with various economic goals and environmental values. The ranchers currently derive no benefits from the bison and have concerns regarding competition between bison and cattle. However, a threshold harvesting strategy with community participation could generate revenue to offset these concerns. It could also provide benefits to the local community, increase state revenue, and increase the size of the bison population while securing its long-term genetic viability. Implementation would initially require facilitation by policy specialists, after which we suggest a Henry Mountains bison partnership could serve as a model for bison recovery efforts elsewhere in North America.
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Miranda M, Cristóbal I, Díaz L, Sicilia M, Molina-Alcaide E, Bartolomé J, Fierro Y, Cassinello J. Ecological effects of game management: does supplemental feeding affect herbivory pressure on native vegetation? WILDLIFE RESEARCH 2015. [DOI: 10.1071/wr15025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context Supplemental feeding of large mammalian herbivores is a common management tool mainly aimed at promoting healthy populations and at increasing productivity and trophy sizes. Such management measure may indirectly affect herbivore effects on plant communities through altered foraging patterns. The quantification of the ecological effects of large herbivore management is important for designing holistic management and conservation programs. Aims Here we aimed at quantifying the ecological effects of supplemental feeding of Iberian red deer, Cervus elaphus hispanicus, on the composition of and on the browsing effects on Mediterranean woody plant community. Methods An experiment was set up in a hunting rangeland located in central Spain, where female deer were kept in enclosures with either exclusive access to natural forages or with additional ad libitum access to a nutritionally rich concentrate. The experiment also included a control area where deer were absent. Key results We observed significant differences in browsing impacts among the supplemented, non-supplemented and control areas, and such effect varied for the different plant species. Plant species which nutritional content complemented that of fodder were more highly consumed, for instance, Erica spp., which digestible fibre content is higher and N content lower than that of provided fodder. The presence of deer and the concentrate supplied, instead, did not influence the relative abundances of shrub species. Conclusions Artificial supplemental feeding provided to ungulates led to increased browsing on plant species which nutritional composition complemented that of the supplement provided. Implications So as to alleviate herbivory impact on all shrubs, we suggest that composition of supplemental feeding should adjust both to the natural forage availability and quality and to ungulate requirements across seasons.
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Biomass and fire dynamics in a temperate forest-grassland mosaic: Integrating multi-species herbivory, climate, and fire with the FireBGCv2/GrazeBGC system. Ecol Modell 2015. [DOI: 10.1016/j.ecolmodel.2014.10.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Porensky LM, Wittman SE, Riginos C, Young TP. Herbivory and drought interact to enhance spatial patterning and diversity in a savanna understory. Oecologia 2013; 173:591-602. [PMID: 23494287 DOI: 10.1007/s00442-013-2637-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 02/25/2013] [Indexed: 11/27/2022]
Abstract
The combination of abiotic stress and consumer stress can have complex impacts on plant community structure. Effective conservation and management of semi-arid ecosystems requires an understanding of how different stresses interact to structure plant communities. We explored the separate and combined impacts of episodic drought, livestock grazing, and wild ungulate herbivory on species co-occurrence and diversity patterns in a relatively productive, semi-arid Acacia savanna. Specifically, we analyzed 9 years of biannual plant community data from the Kenya long-term exclosure experiment, a broad-scale manipulative experiment that has excluded different combinations of large mammalian herbivores from 18 4-ha plots since 1995. During droughts, we observed low species diversity and random species co-occurrence patterns. However, when rain followed a major drought, areas exposed to moderate cattle grazing displayed high species diversity and evidence of significant species aggregation. These patterns were not apparent in the absence of cattle, even if other large herbivores were present. To explore possible mechanisms, we examined patterns separately for common and rare species. We found that aggregation patterns were likely driven by rare species responding similarly to the availability of open micro-sites. Our results indicate that in a productive, fire-suppressed savanna, the combination of periodic drought and moderate cattle grazing can enhance plant biodiversity and fine-scale spatial heterogeneity by opening up space for species that are otherwise rare or cryptic. Our findings also emphasize that domestic herbivores can have significantly stronger impacts on plant community dynamics than wild herbivores, even in an ecosystem with a long history of grazing.
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Affiliation(s)
- Lauren M Porensky
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA,
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Holland EP, Pech RP, Ruscoe WA, Parkes JP, Nugent G, Duncan RP. Thresholds in plant–herbivore interactions: predicting plant mortality due to herbivore browse damage. Oecologia 2012. [PMID: 23188054 DOI: 10.1007/s00442-012-2523-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Estimates of Elk Summer Range Nutritional Carrying Capacity Constrained by Probabilities of Habitat Selection. J Wildl Manage 2006. [DOI: 10.2193/0022-541x(2006)70[283:eoesrn]2.0.co;2] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Weisberg PJ, Coughenour MB. Model-based assessment of aspen responses to elk herbivory in Rocky Mountain National Park, USA. ENVIRONMENTAL MANAGEMENT 2003; 32:152-169. [PMID: 14703920 DOI: 10.1007/s00267-002-0029-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In Rocky Mountain National Park (RMNP), aspen (Populus tremuloides Michx.) has been observed to be declining on elk (Cervus elaphus nelsoni) winter range for many decades. To support elk management decisions, the SAVANNA ecosystem model was adapted to explore interactions between elk herbivory and aspen dynamics. The simulated probability of successful vegetative regeneration for senescent aspen stands declines sharply when elk densities reach levels of 3-5 elk/km2, depending on model assumptions for the seasonal duration of elk foraging activities. For aspen stands with a substantial component of younger trees, the simulated regeneration probability declines more continuously with increasing elk density, dropping below 50% from densities at 8-14 elk/km2. At the landscape scale, simulated aspen regeneration probability under a scenario of extensive seasonal use was little affected by elk population level, when this level was above 300-600 elk (25%-50% current population) over the ca. 107 km2 winter range. This was because elk distribution was highly aggregated, so that a high density of elk occupied certain areas, even at low population levels overall. At approximately current elk population levels (1000-1200 elk), only 35%-45% of senescent aspen stands are simulated as having at least a 90% probability of regeneration, nearly all of them located on the periphery of the winter range. Successful management for aspen persistence on core winter range will likely require some combination of elk population reduction, management of elk distribution, and fencing to protect aspen suckers from elk browsing.
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Affiliation(s)
- Peter J Weisberg
- Mountain Forest Ecology Group, Department of Forest Sciences, Swiss Federal Institute of Technology, ETH-Zentrum HG F21.5, CH-8092, Zurich, Switzerland.
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