scholarly journals Temporal refuges differ between human and natural top-down pressures in a subordinate carnivore

2021 ◽  
Author(s):  
Rumaan Malhotra ◽  
Samantha Lima ◽  
Nyeema Harris
Keyword(s):  
Time Use ◽  
Species Interactions ◽  
Human Impacts ◽  
Apex Predators ◽  
Top Down ◽  
Anthropogenic Pressures ◽  
Multiple Camera ◽  
Urban Rural ◽  
Food Subsidies ◽  
Rural Sites

Animals exhibit variation in their space and time use across an urban-rural gradient. As the top-down influences of apex predators wane due to human-driven declines, landscape level anthropogenic pressures are rising. Human impacts can be analogous to apex predators in that humans can drive increased mortality in both prey species and carnivores, and impact communities through indirect fear effects and food subsidies. Here, we evaluate the time use of a common mesocarnivore across an urban rural gradient, and test whether it is influenced by the intensity of use of a larger carnivore. Using multiple camera-trap surveys, we compared the temporal response of a small carnivore, the raccoon (Procyon lotor), to the larger coyote (Canis latrans) at four sites across Michigan that represented a gradient of pressure from humans. We found that raccoon time use varied by site and was most unique at the rural extreme. Raccoons consistently did not shift their activity pattern in response to coyotes at the site with the highest anthropogenic pressures despite considerable interannual variation, and instead showed the stronger responses to coyotes at more rural sites. Temporal shifts were characterized by raccoons being more diurnal in areas of high coyote activity. We conclude that raccoons do partition time to avoid coyotes. Our results highlight that the variation in raccoon time use across the entirety of the urban-rural gradient needed to be considered, as anthropogenic pressures may dominate and obscure the dynamics of this interaction. In an increasingly anthropocentric world, to understand species interactions, it is imperative that we consider the entire spectrum of human pressures that it may occur within.

scholarly journals Temporal refuges differ between anthropogenic and natural top down pressures in a subordinate carnivore

2020 ◽  
Author(s):  
Rumaan Malhotra ◽  
Samantha Lima ◽  
Nyeema C. Harris
Keyword(s):  
Human Impacts ◽  
Temporal Response ◽  
Apex Predators ◽  
Top Down ◽  
Anthropogenic Pressures ◽  
Multiple Camera ◽  
Disturbed Systems ◽  
Food Subsidies ◽  
Predator Guild ◽  
Fear Effects

ABSTRACTApex predators structure communities through consumptive and non-consumptive pathways. In the carnivore guild, this can result in a within-guild cascade through the suppression of mesocarnivores. As the top-down influences of apex predators wane due to human-driven declines, landscape level anthropogenic pressures are rising. Human impacts can be analogous to apex predators in that humans can drive increased mortality in both prey species and carnivores, and impact communities through indirect fear effects and food subsidies. Here, we evaluate whether anthropogenic top-down pressures can structure communities in a similar manner as apex predators in shaping the interactions of mesocarnivores. Specifically, we expect anthropogenic forces to induce comparable effects as occurrence of apex predators in driving spatiotemporal partitioning between two mesocarnivores. Using multiple camera-trap surveys, we compared the temporal response of a small carnivore, the raccoon (Procyon lotor), to the larger coyote (Canis latrans) at four sites across Michigan that represented opposing gradients of pressure from humans and apex predators. Contrary to our expectations, we found that raccoons shifted their activity pattern in response to coyotes at sites with higher anthropogenic pressures and exhibited no temporal response at sites with apex predators. Temporal shifts were characterized by raccoons being more diurnal in areas of high coyote activity. We conclude that despite superficial similarities, anthropogenic forces do not replace the function of native apex predators in structuring the mesocarnivore guild. As such, an intact and functioning native predator guild remains necessary to preserve spatiotemporal community structure, in natural and disturbed systems alike.

scholarly journals Reintroduced wolves and hunting limit the abundance of a subordinate apex predator in a multi-use landscape

2020 ◽  
Vol 287 (1938) ◽  
pp. 20202202
Author(s):  
L. Mark Elbroch ◽  
Jake M. Ferguson ◽  
Howard Quigley ◽  
Derek Craighead ◽  
Daniel J. Thompson ◽  
...  
Keyword(s):  
Population Model ◽  
Human Impacts ◽  
Adult Survival ◽  
Apex Predator ◽  
Vital Rates ◽  
Grey Wolf ◽  
Apex Predators ◽  
Negative Effects ◽  
Top Down ◽  
Species Abundances

Top-down effects of apex predators are modulated by human impacts on community composition and species abundances. Consequently, research supporting top-down effects of apex predators occurs almost entirely within protected areas rather than the multi-use landscapes dominating modern ecosystems. Here, we developed an integrated population model to disentangle the concurrent contributions of a reintroduced apex predator, the grey wolf, human hunting and prey abundances on vital rates and abundance of a subordinate apex predator, the puma. Increasing wolf numbers had strong negative effects on puma fecundity, and subadult and adult survival. Puma survival was also influenced by density dependence. Overall, puma dynamics in our multi-use landscape were more strongly influenced by top-down forces exhibited by a reintroduced apex predator, than by human hunting or bottom-up forces (prey abundance) subsidized by humans. Quantitatively, the average annual impact of human hunting on equilibrium puma abundance was equivalent to the effects of 20 wolves. Historically, wolves may have limited pumas across North America and dictated puma scarcity in systems lacking sufficient refugia to mitigate the effects of competition.

scholarly journals Incorporating anthropogenic effects into trophic ecology: predator–prey interactions in a human-dominated landscape

2015 ◽  
Vol 282 (1814) ◽  
pp. 20151602 ◽  
Author(s):  
Ine Dorresteijn ◽  
Jannik Schultner ◽  
Dale G. Nimmo ◽  
Joern Fischer ◽  
Jan Hanspach ◽  
...  
Keyword(s):  
Species Interactions ◽  
Structural Equation ◽  
Trophic Ecology ◽  
Camera Traps ◽  
Trophic Levels ◽  
Apex Predators ◽  
Top Down ◽  
Large Herbivores ◽  
Bottom Up ◽  
Combining Data

Apex predators perform important functions that regulate ecosystems worldwide. However, little is known about how ecosystem regulation by predators is influenced by human activities. In particular, how important are top-down effects of predators relative to direct and indirect human-mediated bottom-up and top-down processes? Combining data on species' occurrence from camera traps and hunting records, we aimed to quantify the relative effects of top-down and bottom-up processes in shaping predator and prey distributions in a human-dominated landscape in Transylvania, Romania. By global standards this system is diverse, including apex predators (brown bear and wolf), mesopredators (red fox) and large herbivores (roe and red deer). Humans and free-ranging dogs represent additional predators in the system. Using structural equation modelling, we found that apex predators suppress lower trophic levels, especially herbivores. However, direct and indirect top-down effects of humans affected the ecosystem more strongly, influencing species at all trophic levels. Our study highlights the need to explicitly embed humans and their influences within trophic cascade theory. This will greatly expand our understanding of species interactions in human-modified landscapes, which compose the majority of the Earth's terrestrial surface.

Rural sites in Roman Greece

2014 ◽  
Vol 60 ◽  
pp. 117-132 ◽  
Author(s):  
Daniel Stewart
Keyword(s):  
Field Survey ◽  
Rural Landscape ◽  
Greek Life ◽  
Landscape Studies ◽  
The Past ◽  
Roman Greece ◽  
Urban Core ◽  
Urban Rural ◽  
Rural Sites ◽  
Textual Research

[W]hile pretending to throw some light upon classical authors by careful observation of the manners of the present day, romantic travellers succeeded in fact in accommodating reality to their dreams … by creating for themselves and for their readers carefully edited portraits of modern Greece that transformed the present into the living image of the past (Saïd 2005: 291).Thirty years ago archaeological field survey promised to reshape radically our understanding of the countryside (Keller and Rupp 1983: 1–5). Traditional archaeological approaches to cities and monuments were increasingly seen to be extensions of textual research, and research on the rural landscape was envisaged as a way to access the other side of the traditional urban-rural dichotomy (though see the comments in Alcock 2007: 671–72). Some scholars estimated that, in the Classical period, the vast majority of Greek poleis had populations of less than 3,000 and territories no more than a few hours” walk from the urban core. Given that, they asked, does it make sense to divide elements of Greek life into “city” and “country”? In a sense, the study of landscapes was seen as a way to redress perceived imbalances between this urban-rural division and the picture painted by the ancient sources of Roman Greece as a pale reflection of its Classical brilliance. In the years since, landscape studies have grown to include much more than archaeological field survey, but this tension between textual and archaeological narratives remains at the heart of understandings of rural Roman Greece.

Predator–prey interactions and climate change

2019 ◽  
pp. 199-220 ◽  
Author(s):  
Vincent Bretagnolle ◽  
Julien Terraube
Keyword(s):  
Climate Change ◽  
Species Interactions ◽  
Experimental Studies ◽  
Trophic Levels ◽  
Generalist Predators ◽  
Top Down ◽  
Predator Prey ◽  
Key Topics ◽  
Available Information

Climate change is likely to impact all trophic levels, although the response of communities and ecosystems to it has only recently received considerable attention. Further, it is expected to affect the magnitude of species interactions themselves. In this chapter, we summarize why and how climate change could affect predator–prey interactions, then review the literature about its impact on predator–prey relationships in birds, and provide prospects for future studies. Expected effects on prey or predators may include changes in the following: distribution, phenology, population density, behaviour, morphology, or physiology. We review the currently available information concerning particular key topics: top-down versus bottom-up control, specialist versus generalist predators, functional versus numerical responses, trophic cascades and regime shifts, and lastly adaptation and selection. Finally, we focus our review on two well-studied bird examples: seabirds and raptors. Key future topics include long-term studies, modelling and experimental studies, evolutionary questions, and conservation issues.

scholarly journals Rural-to-Urban Transition in Chongqing’s Hinterland: State-Led Urbanisation or Urbanisation From Below?

2020 ◽  
pp. 186810262091499
Author(s):  
Florian Thünken
Keyword(s):  
Field Research ◽  
Top Down ◽  
Bottom Up ◽  
Municipal Governments ◽  
Provincial Level ◽  
Urban Transition ◽  
Urban Rural ◽  
Big Cities ◽  
Chinese State

Since 2014 the Chinese state has been pushing for “new-style urbanisation.” Its main goals are accelerated urban–rural integration, development of small-to-medium cities and towns, and a “people-centered” urbanisation, all while limiting movement towards big cities. Similar reforms have been experimented with in Chongqing since 2007. This article argues that we need to take both top-down and bottom-up processes into view if we are to understand completely the intricate transformation currently underway in China’s urbanising society. Thus, policies and programmes at the national and provincial level are examined and then contrasted with findings from field research, that has been conducted in Chongqing’s urbanising hinterland. Findings show patterns of rural-to-urban transitioning which apparently match the central and municipal governments’ plans, but further evidence points to the rejection or modification of state-led urbanisation efforts and towards an urbanisation on the people’s own terms.

Agency and social construction of space under top-down planning: Resettled rural residents in China

Urban Studies ◽  
2017 ◽  
Vol 55 (7) ◽  
pp. 1541-1560 ◽  
Author(s):  
Min Zhang ◽  
Weiping Wu ◽  
Weijing Zhong
Keyword(s):  
Rural Communities ◽  
Public Space ◽  
Local Governments ◽  
Transition Process ◽  
Benefit Sharing ◽  
Top Down ◽  
Social Fabric ◽  
Urban Rural ◽  
Farmland Conservation ◽  
Village Life

Resettled rural communities are a product of China’s rapid urbanisation and associated top-down planning. For local governments, relocating farmers from natural villages into new, concentrated residential neighbourhoods serves the dual purpose of implementing national directives on farmland conservation and integrated urban–rural planning. For resettled residents, however, the transition process is fraught with livelihood, social and cultural contest. This paper explores how such residents in a Chinese city, Zhenjiang, exercise agency to reconstruct community and public space in their new neighbourhood. Keeping alive patterns and practice of thoughts acquired during their rural lives, habitus, resettled residents have deployed their new spatial situation in creative ways. Pre-existing social fabric and mutual benefit-sharing provide the foundation for spatial adaptation and transformation, allowing residents to achieve a sense of normalcy or even to recreate village life. Theoretically, our analysis highlights the importance of situating spatial agency within the context of shifting regime of property rights and its effect on the maintenance of habitus.

Effects of level of socio-economic development on course of non-affective psychosis

1997 ◽  
Vol 171 (3) ◽  
pp. 256-259 ◽  
Author(s):  
Vijoy K. Varma ◽  
N. N. Wig ◽  
B. M. Tripathi ◽  
Arun K. Misra ◽  
C. B. Khare ◽  
...  
Keyword(s):  
Economic Development ◽  
Urban Area ◽  
Affective Psychosis ◽  
Catchment Areas ◽  
Socio Economic Development ◽  
Urban Rural ◽  
Rural Sites

BackgroundThis study explored the relation of level of socio-economic development to the course of non-affective psychosis, by extending the analysis of urban/rural differences in course in Chandigarh, India.MethodThe proportion of ‘best outcome cases between urban (n=110) and rural (n=50) catchment areas were compared at two-year follow-up, separately for CATEGO S+ and non-S+ schizophrenia.ResultsThe proportion of subjects with ‘best outcome’ ratings at the urban and rural sites, respectively, was similar for CATEGO S+ schizophrenia (29 v. 29%), but significantly different for non-S+ psychosis (26 v. 47%)ConclusionsThe fact that in rural Chandigarh, psychoses have a more favourable course than in the urban area may be explained in large part by psychoses distinct from ‘nuclear’ schizophrenia.

scholarly journals Temporal partitioning and spatiotemporal avoidance among large carnivores in a human-impacted African landscape

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0256876
Author(s):  
Charlotte E. Searle ◽  
Josephine B. Smit ◽  
Jeremy J. Cusack ◽  
Paolo Strampelli ◽  
Ana Grau ◽  
...  
Keyword(s):  
Human Impacts ◽  
Activity Patterns ◽  
Species Conservation ◽  
Travel Behaviour ◽  
Sympatric Species ◽  
Large Carnivores ◽  
East African ◽  
Anthropogenic Pressures ◽  
Coexistence Mechanisms ◽  
Wild Dog

Africa is home to some of the world’s most functionally diverse guilds of large carnivores. However, they are increasingly under threat from anthropogenic pressures that may exacerbate already intense intra-guild competition. Understanding the coexistence mechanisms employed by these species in human-impacted landscapes could help shed light on some of the more subtle ways in which humans may impact wildlife populations, and inform multi-species conservation planning. We used camera trap data from Tanzania’s Ruaha-Rungwa landscape to explore temporal and spatiotemporal associations between members of an intact East African large carnivore guild, and determine how these varied across gradients of anthropogenic impact and protection. All large carnivores except African wild dog (Lycaon pictus) exhibited predominantly nocturnal road-travel behaviour. Leopard (Panthera pardus) appeared to employ minor temporal avoidance of lion (Panthera leo) in all sites except those where human impacts were highest, suggesting that leopard may have been freed up from avoidance of lion in areas where the dominant competitor was less abundant, or that the need for leopard to avoid humans outweighed the need to avoid sympatric competitors. Lion appeared to modify their activity patterns to avoid humans in the most impacted areas. We also found evidence of avoidance and attraction among large carnivores: lion and spotted hyaena (Crocuta crocuta) followed leopard; leopard avoided lion; spotted hyaena followed lion; and lion avoided spotted hyaena. Our findings suggest that large carnivores in Ruaha-Rungwa employ fine-scale partitioning mechanisms to facilitate coexistence with both sympatric species and humans, and that growing human pressures may interfere with these behaviours.

scholarly journals A METHOD FOR THE SPATIAL ANALYSIS OF ANTHROPOGENIC PRESSURES IN SPANISH MARINE WATERS

2012 ◽  
Vol 1 (33) ◽  
pp. 64 ◽  
Author(s):  
Isabel Moreno ◽  
Irene Del Barrio ◽  
Ana Lloret ◽  
Ainhoa Pérez-Puyol
Keyword(s):  
Human Activities ◽  
Spatial Information ◽  
Human Impacts ◽  
Marine Waters ◽  
Anthropogenic Pressures ◽  
Marine Management ◽  
Gis Tools ◽  
Environmental Status ◽  
Good Environmental Status ◽  
Official Sources

In 2008, the European Community adopted the Marine Strategy Framework Directive, aiming to achieve or maintain good environmental status in the European marine environment by 2020, applying an ecosystem-based approach to the management of human activities. Spatial information of the distribution of the human activities and their related pressures is essential to accomplish this task successfully. After compiling the available data from official sources, the spatial extent of the land-based and ocean-based human activities that could have an impact on the Spanish marine waters were estimated and mapped using GIS tools. In addition, a series of indexes were created in order to develop a cumulative analysis, taking into account the different relevance of pressures and that single pressures have different intensities. The identification of areas with an accumulation of pressures revealed that it is in coastal waters around big cities where the greater part of the pressures concentrates for each of the five Spanish marine districts. Human impacts emanating from the identified pressures could not be evaluated and this task is proposed to be accomplished in further projects. Nonetheless, the resulting information is considered very useful for managers and technical staff to support not only marine management but also other planning and decision making in Spain.

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