Effects of a New Pedestrian Pathway in Grand Teton National Park on Breeding Sagebrush Songbirds

Human-induced changes to natural landscapes have become ubiquitous, resulting in exposure of wildlife populations to novel stressors (Munns 2006). While it is clear that changes such as habitat loss can directly impact wildlife species, less clear is the extent to which human presence itself functions as a disturbance that influences wildlife behaviors with important fitness consequences. Animals clearly respond to perceived risk of predation by natural predators via, for example, fleeing, or altering foraging and/or breeding habitat selection (Marzluff 1988, Hakkarainen et al. 2001, Frid and Dill2002, Blumstein 2006, Borkowski et al. 2006, Fontaine and Martin 2006). Such responses can alter access to important resources, energy budgets, and therefore attributes such as body condition (Bechet et al. 2004) with potential impacts to survival and reproductive output. Of critical importance to the management of wildlife populations is therefore to determine 1) whether wildlife species perceive human presence as predation risk, 2) how individuals respond to such risk, and 3) how such responses influence fitness consequences and therefore population dynamics and community structure.

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COVID-19 Restrictions in a Nature Reserve Reveal the Costs of Human Presence for the Threatened Nubian Ibex (Capra nubiana)

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.751515 ◽

2021 ◽

Vol 9 ◽

Author(s):

Yuval Zukerman ◽

Zehava Sigal ◽

Oded Berger-Tal

Keyword(s):

Water Source ◽

Nature Reserves ◽

Water Pool ◽

Natural Habitats ◽

Human Presence ◽

Wildlife Species ◽

Trail Cameras ◽

The Impact ◽

Preferred Hours ◽

Rare Opportunity

The increasing pressure of ecotourism on wildlife in their natural habitats leads many wild animals to alter their behaviors. The restrictions issued in many places due to COVID-19 provide a rare opportunity to examine wildlife behavior in nature reserves with reduced human presence, and to reveal the impact of human visitation on the behaviors and fitness of local wildlife species. In 2019 and 2020 we placed trail cameras next to two natural springs in the Israeli Negev Desert, Ein-Avdat and Ein-Shaviv, located 9 km apart. Both sites serve as the main water source for local Nubian ibex (Capra nubiana) populations, but Ein-Avdat is situated within a popular national park into which visitors’ entrance was restricted due to COVID-19 regulations in 2020, while Ein-Shaviv is more remote and thus attracts only few visitors regardless of COVID-19 regulations. Our study revealed that during 2020, ibex in Ein-Avdat arrived to drink earlier in the day and the population’s Female:Kids ratio more than doubled. These changes were not observed in Ein-Shaviv. We found that the daily number of visitors in Ein-Avdat affected the arrival time of ibex to the water pool. We conclude that the reduced number of visitors to Ein-Avdat in 2020 compared to 2019 may have allowed ibex to arrive in preferred hours, and may have contributed to the increased kid-to-females ratio. Our study shows that behavioral adaptions to human visitation in nature reserves might carry a high fitness cost.

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Female mouthbrooders adjust incubation duration to perceived risk of predation

Animal Behaviour ◽

10.1016/j.anbehav.2004.03.005 ◽

2004 ◽

Vol 68 (6) ◽

pp. 1275-1281 ◽

Cited By ~ 27

Author(s):

Barbara Taborsky ◽

Katharina Foerster

Keyword(s):

Perceived Risk ◽

Risk Of Predation ◽

Incubation Duration

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Invisible barriers: anthropogenic impacts on inter- and intra-specific interactions as drivers of landscape-independent fragmentation

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2018.0049 ◽

2019 ◽

Vol 374 (1781) ◽

pp. 20180049 ◽

Cited By ~ 10

Author(s):

Oded Berger-Tal ◽

David Saltz

Keyword(s):

Anthropogenic Disturbance ◽

Scientific Literature ◽

Anthropogenic Impacts ◽

Interspecific Interactions ◽

Specific Interactions ◽

Physical Transformation ◽

Wildlife Populations ◽

Induced Changes ◽

Species Declines ◽

Dynamics Of Populations

Anthropogenically induced fragmentation constitutes a major threat to biodiversity. Presently, conservation research and actions focus predominantly on fragmentation caused directly by physical transformation of the landscape (e.g. deforestation, agriculture, urbanization, roads, etc.). While there is no doubt that landscape features play a key role in fragmenting populations or enhancing connectivity, fragmentation may also come about by processes other than the transformation of the landscape and which may not be readily visible. Such landscape-independent fragmentation (LIF) usually comes about when anthropogenic disturbance alters the inter- and intra-specific interactions among and within species. LIF and its drivers have received little attention in the scientific literature and in the management of wildlife populations. We discuss three major classes of LIF processes and their relevance for the conservation and management of species and habitats: (i) interspecific dispersal dependency, in which populations of species that rely on other species for transport and propagation become fragmented as the transporting species declines; (ii) interspecific avoidance induction, where species are excluded from habitats and corridors owing to interspecific interactions resulting from anthropogenically induced changes in community structure (e.g. exclusions by increased predation pressure); and (iii) intraspecific behavioural divergence, where populations become segregated owing to anthropogenically induced behavioural differentiation among them. This article is part of the theme issue ‘Linking behaviour to dynamics of populations and communities: application of novel approaches in behavioural ecology to conservation'.

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Effect of Turbidity on the Predator Avoidance Behaviour of Juvenile Chinook Salmon (Oncorhynchus tshawytscha)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f93-027 ◽

1993 ◽

Vol 50 (2) ◽

pp. 241-246 ◽

Cited By ~ 128

Author(s):

Robert S. Gregory

Keyword(s):

Chinook Salmon ◽

Perceived Risk ◽

Predator Avoidance ◽

Oncorhynchus Tshawytscha ◽

Avoidance Behaviour ◽

Fish Predator ◽

Juvenile Chinook Salmon ◽

Risk Of Predation ◽

Juvenile Chinook ◽

Predator Risk

The effect of turbidity on the predator avoidance behaviour of juvenile chinook salmon (Oncorhynchus tshawytscha) was determined in controlled laboratory experiments. Bird and fish models were used to simulate predator risk. In the absence of risk, juvenile chinook were distributed randomly within an experimental arena in turbid conditions (≈23 NTU), but in clear conditions (<1 NTU) they associated with the bottom. When introduced to bird and fish predator models, the chinook altered their distribution and occupied deeper parts of the arena regardless of turbidity level. However, their responses in turbid conditions were less marked and of shorter duration. Turbidity apparently reduced the perceived risk of predation in juvenile chinook.

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Monopolization of food by zebrafish (Danio rerio) increases in risky habitats

Canadian Journal of Zoology ◽

10.1139/z02-199 ◽

2002 ◽

Vol 80 (12) ◽

pp. 2164-2169 ◽

Cited By ~ 39

Author(s):

Ian M Hamilton ◽

Lawrence M Dill

Keyword(s):

Danio Rerio ◽

Coefficient Of Variation ◽

Perceived Risk ◽

Open Habitat ◽

Risk Of Predation ◽

Resource Monopolization

Dominant zebrafish (Danio rerio) previously have been shown to reduce their monopolization of food when foraging in structurally complex habitats compared with open habitats. Complex habitats may be more difficult to defend but may also be safer. To decouple these effects, we compared aggression and monopolization of food in groups of zebrafish foraging in an open habitat and one with overhead cover, as well as in an open habitat and a complex (vegetated) habitat. Covered and open habitats should have been equally defendable. In our experiments, fish used covered habitats more than open ones, suggesting that the perceived risk of predation was lower in covered habitats. There was no difference in use of vegetated and open habitats, suggesting that these habitats, which should differ in defendability, did not differ in safety. We found that the degree of food monopolization (expressed in the coefficient of variation within groups) at risky feeders was significantly greater in open habitats than in covered, but not vegetated, habitats. We did not find a difference in aggression between habitats. These results indicate that resource monopolization in groups of zebrafish is greater in risky habitats and support the hypothesis that the lower monopolization of food in complex habitats could result from greater safety in those habitats rather than, or in addition to, the reduction in defendability.

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Foraging Response to Risks of Predation and Competition in Artificial Pools

Israel Journal of Ecology and Evolution ◽

10.1560/ijee.56.1.9 ◽

2010 ◽

Vol 56 (1) ◽

pp. 9-20 ◽

Cited By ~ 8

Author(s):

Gil Stav ◽

Burt P. Kotler ◽

Leon Blaustein

Keyword(s):

Perceived Risk ◽

Foraging Activity ◽

Left Behind ◽

Similar Tendency ◽

Green Toad ◽

Risk Of Predation ◽

Giving Up Density ◽

Culiseta Longiareolata ◽

The Rich ◽

Resource Patches

Although ecologists have learned much about the influence of competitors and perceived risk of predation on foraging in terrestrial systems by measuring giving-up density (GUD, the amount of food left behind in a resource patch following exploitation), GUDs have rarely been used in aquatic environments. Here we use foraging activity (proportion foraging) and GUDs to assess the effects that two periphyton consumers and potential competitors, green toad (Bufo viridis) tadpoles and mosquito (Culiseta longiareolata) larvae, have on each other. We also examine the effects of perceived risk of predation imposed by a dragonfly nymph (Anax imperator). To do so, we conducted an artificial pool experiment and developed a food patch appropriate for measuring GUDs for periphyton grazers. MoreCulisetaindividuals foraged in rich food patches than in poor patches.Bufoshowed a similar tendency. FewerBufoforaged in both patch types in the presence of cagedAnax. Culisetashowed a similar tendency. However, in the rich patches, onlyBuforeduced foraging activity when the caged predator was present. BothBufoandCulisetadepleted food patches through exploitation, resulting in lower GUDs. Both competitors together resulted in lower GUDs than did food depletion of each species alone. However, the presence of cagedAnaxhad little or no effects on GUDs. Overall, bothBufoandCulisetarespond to food and safety. They are able to direct foraging effort to richer patches and devote more time to those patches, and they respond to predation risk by choosing whether or not to exploit resource patches.

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Environmental deterioration increases tadpole vulnerability to predation

Biology Letters ◽

10.1098/rsbl.2008.0144 ◽

2008 ◽

Vol 4 (4) ◽

pp. 392-394 ◽

Cited By ~ 20

Author(s):

Zoe E Squires ◽

Paul C.E Bailey ◽

Richard D Reina ◽

Bob B.M Wong

Keyword(s):

Separate Experiment ◽

Freshwater Organisms ◽

Elevated Salinity ◽

Fitness Consequences ◽

Risk Of Predation ◽

Freshwater Habitats ◽

Speed Performance ◽

Predator Response ◽

Aquatic Contaminants ◽

Sublethal Concentrations

Human-induced environmental change is occurring at an unprecedented rate and scale. Many freshwater habitats, in particular, have been degraded as a result of increased salinity. Little is known about the effects of anthropogenic salinization on freshwater organisms, especially at sublethal concentrations, where subtle behavioural changes can have potentially drastic fitness consequences. Using a species of Australian frog ( Litoria ewingii ), we experimentally examined the effects of salinization on tadpole behaviour and their vulnerability to a predatory dragonfly nymph ( Hemianax papuensis ). We found that tadpoles exposed to an ecologically relevant concentration of salt (15% seawater, SW) were less active than those in our freshwater control (0.4% SW). Tadpoles in elevated salinity also experienced a higher risk of predation, even though the strike rate of the predator did not differ between salt and freshwater treatments. In a separate experiment testing the burst-speed performance of tadpoles, we found that tadpoles in saltwater were slower than those in freshwater. Thus, it would appear that salt compromised the anti-predator response of tadpoles and made them more susceptible to being captured. Our results demonstrate that environmentally relevant concentrations of aquatic contaminants can, even at sublethal levels, severely undermine the fitness of exposed organisms.

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The strength of a female mate preference increases with predation risk

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2008.1070 ◽

2008 ◽

Vol 276 (1657) ◽

pp. 775-780 ◽

Cited By ~ 28

Author(s):

Tae Won Kim ◽

John H Christy ◽

Stefan Dennenmoser ◽

Jae C Choe

Keyword(s):

Sexual Selection ◽

Predation Risk ◽

Perceived Risk ◽

General Pattern ◽

Visual Orientation ◽

Relative Preference ◽

Avian Predators ◽

Risk Of Predation ◽

Courtship Signals ◽

Perceived Predation Risk

When females search for mates and their perceived risk of predation increases, they less often express preferences for males that use conspicuous courtship signals, relaxing sexual selection on production of these signals. Here, we report an apparent exception to this general pattern. Courting male fiddler crabs Uca beebei sometimes build pillars of mud at the openings to their burrows in which crabs mate. Females visit several males before they choose a mate by staying and breeding in their burrows, and they preferentially visit males with pillars. Previous studies suggested that this preference is based on a visual orientation behaviour that may reduce females' risk of predation while searching for a mate. We tested this idea by determining whether the female preference for males with pillars increases with perceived predation risk. We attracted avian predators to where crabs were courting and measured the rates that sexually receptive females visited courting males with and without mud pillars. Under elevated risk, females continued to search for mates and they showed a stronger relative preference for males with pillars. Thus, when predation risk is high, females may continue to express preferences that are under natural selection because they help females avoid predation, strengthening sexual selection for use of the preferred signal.

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The role of New Zealand endemic lizards in Salmonella transmission in the takahē translocation network

10.26686/wgtn.16779166 ◽

2021 ◽

Author(s):

◽

Shanna Rose

Keyword(s):

New Zealand ◽

Sympatric Species ◽

Soil Samples ◽

Seasonal Patterns ◽

Salmonella Infection ◽

Wildlife Species ◽

The World ◽

Wildlife Populations ◽

Significant Mortality

<p>The dynamics of disease in wildlife populations often involve a complex relationship between physiological, environmental and ecological variables. Defining the pattern of pathogen infection between primary hosts, sympatric species and their environments is crucial in the understanding of potential impacts a pathogen may have on its host species. Very little is known about pathogens of native, New Zealand wildlife. Understanding the role pathogens play in structuring communities is crucial in the conservation of threatened New Zealand wildlife species. Salmonella is an important pathogen of reptiles, birds and mammals, and Salmonellosis has caused significant mortality in wildlife around the world. Recently, Salmonella has been isolated from takahē from a private island in the takahē translocation network. Reptiles have been implicated as asymptomatic carriers and transmitters of Salmonella, and lizards from a private (undisclosed) island have been implicated in the transmission of Salmonella to takahē. To investigate the capacity for lizards to act as a Salmonella reservoir in the takahē translocation network, I examined the distribution, abundance and Salmonella prevalence of lizards within takahē territories on the private island and on Maud Island where takahē also reside. Additionally, I investigated the presence of Salmonella in soil and water samples from takahē territories on the private island, Maud Island and at the Burwood Bush takahē rearing facility. Lizard densities on the private island were estimated to be between 466-6020 lizards/ha, and 118-1528 lizards/ha on Maud Island. Salmonella serovars concurrent with those isolated from takahē were isolated from 2% of lizards, 25% of water and 50% of soil samples on the private island, indicating that lizards and the environment play an important role in transmission and maintenance of Salmonella to takahē. Salmonella was not isolated from lizards or environmental samples on Maud Island or at Burwood Bush, indicating prevalence too low to detect in this study or a Salmonella reservoir unique to the private island. Further investigation of Salmonella sources; serovars and seasonal patterns of Salmonella infection is needed to better inform takahē translocation actions on the private island. Additionally, further examination of Salmonella in lizards and the environment is necessary to assess the risk of Salmonella infection to takahē on Maud Island.</p>

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