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 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.

Seven considerations about dingoes as biodiversity engineers: the socioecological niches of dogs in Australia

2012 ◽  
Vol 34 (1) ◽  
pp. 119 ◽  
Author(s):  
Peter J. S. Fleming ◽  
Benjamin L. Allen ◽  
Guy-Anthony Ballard
Keyword(s):  
Biodiversity Conservation ◽  
Adaptive Management ◽  
Landscape Changes ◽  
Apex Predator ◽  
Mesopredator Release ◽  
Negative Effects ◽  
Top Down ◽  
Management Framework ◽  
Human Perceptions ◽  
Threatened Fauna

Australian dingoes have recently been suggested as a tool to aid biodiversity conservation through the reversal or prevention of trophic cascades and mesopredator release. However, at least seven ecological and sociological considerations must be addressed before dog populations are positively managed.Domestication and feralisation of dingoes have resulted in behavioural changes that continue to expose a broad range of native and introduced fauna to predation.Dingoes and other dogs are classic mesopredators, while humans are the apex predator and primary ecosystem engineers in Australia.Anthropogenic landscape changes could prevent modern dingoes from fulfilling their pre-European roles.Dingoes are known to exploit many of the same species they are often presumed to ‘protect’, predisposing them to present direct risks to many threatened species.The assertion that contemporary dog control facilitates the release of mesopredators disregards the realities of effective dog control, which simultaneously reduces fox and dog abundance and is unlikely to enable increases in fox abundance.The processes affecting threatened fauna are likely a combination of both top-down and bottom-up effects, which will not be solved or reversed by concentrating efforts on managing only predator effects.Most importantly, human social and economic niches are highly variable across the ecosystems where dingoes are present or proposed. Human perceptions will ultimately determine acceptance of positive dingo management.Outside of an adaptive management framework, positively managing dingoes while ignoring these seven considerations is unlikely to succeed in conserving native faunal biodiversity but is likely to have negative effects on ecological, social and economic values.

scholarly journals A Demo-Genetic Analysis of a Small Reintroduced Carnivore Population: The Otter (Lutra lutra) in The Netherlands

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Maelle Seignobosc ◽  
Lia Hemerik ◽  
Hans Peter Koelewijn
Keyword(s):  
The Netherlands ◽  
Conservation Strategy ◽  
Adult Survival ◽  
Vital Rates ◽  
Negative Effects ◽  
Modelling Framework ◽  
Animal Populations ◽  
Female Survival ◽  
Survival And Reproduction ◽  
The Right

Assessing the viability of reintroduced animal populations is a complicated task. Reintroductions are usually carried out with a small number of individuals, thereby, limiting the possibilities for monitoring because of the possible negative effects of intensive monitoring on survival and reproduction. Moreover, reintroduction studies are part of a socioeconomic interplay of forces, thereby, also limiting monitoring possibilities. Also, knowledge of population demography and abundance can be incomplete or unattainable. Here, we illustrate how we combined traditional telemetry and novel non-invasive genetic methodology to construct a detailed life table of a small reintroduced otter population in The Netherlands. Combining an appropriate capture-mark-recapture framework with a matrix modelling approach provides, in general, useful insights for such populations. The data indicated that (i) male survival is lower than female survival, (ii) the reintroduced population is currently growing (estimatedλ=1.26: range [1.06, 1.42]) and seems viable, (iii) increasing adult survival is currently the critical stage at which efforts of field managers should concentrate, and (iv) the modelling framework allowed us to determine the boundary conditions for the vital rates under which the population would go extinct. The applied approach directs at measurements that help field managers to implement the right conservation strategy after reintroductions.

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 Predatory fishes affect trophic cascades and apparent competition in temperate reefs

2010 ◽  
Vol 6 (4) ◽  
pp. 533-536 ◽  
Author(s):  
Alejandro Frid ◽  
Jeff Marliave
Keyword(s):  
Trophic Cascade ◽  
Apparent Competition ◽  
Apex Predators ◽  
Negative Effects ◽  
Top Down ◽  
Marine Communities ◽  
Temperate Reefs ◽  
Spatio Temporal ◽  
Predatory Fishes ◽  
Positive Effect

We provide evidence for a trophic cascade involving apex predators and mesopredators of marine temperate reefs, lingcod and rockfish, respectively. We measured spatio-temporal variation in the relative abundance of lingcod, subadult rockfish and two shrimp groups eaten by rockfish ( Pandalus sp. and three smaller-bodied genera aggregated). Lingcod had an indirect positive effect on shrimps, as mediated by the direct negative effects of lingcod on rockfish and of rockfish on shrimps. These top-down effects on shrimps, however, were stronger for Pandalus than for small-bodied shrimps. Further, abundances of Pandalus and small-bodied shrimps were negatively correlated and the latter had a stronger positive effect on rockfish, suggesting that rockfish mediated asymmetrical apparent competition between shrimps. Our results indicate mechanisms by which predatory fishes may influence the structure of marine communities.

First wolves in Luxembourg since 1893, originating from the Alpine and Central European populations

Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Laurent Schley ◽  
Marianne Jacobs ◽  
Sebastian Collet ◽  
Alexander Kristiansen ◽  
Jan Herr
Keyword(s):  
Canis Lupus ◽  
Dna Analysis ◽  
Carcass Characteristics ◽  
Management Plan ◽  
Apex Predator ◽  
Grey Wolf ◽  
Melting Pot ◽  
Central European ◽  
The Past ◽  
Hard Evidence

Abstract Considering the spread of the grey wolf (Canis lupus) in Europe over the past 30 years, Luxembourg took some measures to prepare for the return of this apex predator, including the establishment of a management plan that notably addresses the issue of wolf depredation on livestock. Here we present the results of genetic analyses of putative wolf saliva, hair and scat samples collected from or near prey carcasses between 2015 and 2020. In two cases, the wolf was confirmed via DNA analysis: in July 2017 near Garnich and in April 2020 near Niederanven, both assigned to category C1 (hard evidence). A third case was classified as C2 (confirmed observation) based on prey carcass characteristics, while genetic analysis yielded no result. These are the first confirmed records of wolves in Luxemburg since 1893. Moreover, the two C1-cases originated from the Alpine (Garnich) and Central European (Niederanven) populations. Given similar developments in the neighboring countries and regions, we conclude that the area including the Benelux countries as well as Rhineland-Palatinate, Saarland and Northern France may well become a melting pot for wolves of the two aforementioned populations in the coming years and decades.

scholarly journals Identifying Human-Induced Spatial Differences of Soil Erosion Change in a Hilly Red Soil Region of Southern China

2019 ◽  
Vol 11 (11) ◽  
pp. 3103
Author(s):  
Dong Huang ◽  
Xiaohuan Yang ◽  
Hongyan Cai ◽  
Zuolin Xiao ◽  
Dongrui Han
Keyword(s):  
Soil Erosion ◽  
Human Impact ◽  
Human Impacts ◽  
Southern China ◽  
Red Soil ◽  
Jiangxi Province ◽  
Negative Effects ◽  
Gravity Center ◽  
Local Conditions ◽  
Spatial Differences

Soil erosion (SE) processes are closely related to natural conditions and human activities, posing a threat to environment and society. Identifying the human impact on regional SE changes is increasingly essential for pertinent SE management. Jiangxi province is studied here as a representative area of hilly-red-soil regions within southern China. The main objectives of this study were to investigate the changing trend of SE within Jiangxi and identify human impacts on regional SE change from the perspective of spatial differences, through a new approach based on a gravity-center model. Our results showed that SE status presented an overall amelioration from 1990 to 2015, while the average soil erosion modulus (SEM) declined from 864 to 281 Mg/(km2·a). Compared to the situation under human and natural impacts, human-induced spatial differences of SE change demonstrated that the western and northwest regions showed stronger negative effects; the southern region shifted towards negative effects; the northeast region presented a much weaker negative effect. Our results indicated that 4 cities with strong negative effects need more attention in further SE management suited to their local conditions and development, and also suggested that the approach based on a gravity-center has potential for identifying the human impact on regional SE change from the perspective of spatial patterns.

scholarly journals Host Plant Species Mediates Impact of Neonicotinoid Exposure to Monarch Butterflies

Insects ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 999
Author(s):  
Cody Prouty ◽  
Paola Barriga ◽  
Andrew K. Davis ◽  
Vera Krischik ◽  
Sonia Altizer
Keyword(s):  
Host Plant ◽  
Adult Survival ◽  
Low Doses ◽  
Flight Performance ◽  
Protective Effects ◽  
Plant Type ◽  
Negative Effects ◽  
Monarch Butterflies ◽  
Negative Impacts ◽  
Chemical Retention

Neonicotinoids are the most widely used insecticides in North America. Numerous studies document the negative effects of neonicotinoids on bees, and it remains crucial to demonstrate if neonicotinoids affect other non-target insects, such as butterflies. Here we examine how two neonicotinoids (imidacloprid and clothianidin) affect the development, survival, and flight of monarch butterflies, and how these chemicals interact with the monarch’s milkweed host plant. We first fed caterpillars field-relevant low doses (0.075 and 0.225 ng/g) of neonicotinoids applied to milkweed leaves (Asclepias incarnata), and found no significant reductions in larval development rate, pre-adult survival, or adult flight performance. We next fed larvae higher neonicotinoid doses (4–70 ng/g) and reared them on milkweed species known to produce low, moderate, or high levels of secondary toxins (cardenolides). Monarchs exposed to the highest dose of clothianidin (51–70 ng/g) experienced pupal deformity, low survival to eclosion, smaller body size, and weaker adult grip strength. This effect was most evident for monarchs reared on the lowest cardenolide milkweed (A. incarnata), whereas monarchs reared on the high-cardenolide A. curassavica showed no significant reductions in any variable measured. Our results indicate that monarchs are tolerant to low doses of neonicotinoid, and that negative impacts of neonicotinoids depend on host plant type. Plant toxins may confer protective effects or leaf physical properties may affect chemical retention. Although neonicotinoid residues are ubiquitous on milkweeds in agricultural and ornamental settings, commonly encountered doses below 50 ng/g are unlikely to cause substantial declines in monarch survival or migratory performance.

Sustainability in Arid Grasslands: New Technology Applications for Management

2005 ◽  
Author(s):  
Thomas K. Budge ◽  
Arian Pregenzer
Keyword(s):  
Human Impacts ◽  
Well Being ◽  
Human Populations ◽  
Natural Systems ◽  
Resource Sustainability ◽  
Technology Applications ◽  
Species Abundances ◽  
Ecosystem Studies ◽  
Grazing Systems ◽  
Arid Grasslands

As biodiversity, ecosystem function, and ecosystem services become more closely linked with human well-being at all scales, the study of ecology takes on increasing social, economic, and political importance. However, when compared with other disciplines long linked with human well-being, such as medicine, chemistry, and physics, the technical tools and instruments of the ecologist have generally lagged behind those of the others. This disparity is beginning to be overcome with the increasing use of biotelemetric techniques, microtechnologies, satellite and airborne imagery, geographic information systems (GIS), and both regional and global data networks. We believe that the value and efficiency of ecosystem studies can advance significantly with more widespread use of existing technologies, and with the adaptation of technologies currently used in other disciplines to ecosystem studies. More importantly, the broader use of these technologies is critical for contributing to the preservation of biodiversity and the development of sustainable natural resource use by humans. The concept of human management of biodiversity and natural systems is a contentious one. However, we assert that as human population and resource consumption continue to increase, biodiversity and resource sustainability will only be preserved by increasing management efforts—if not of the biodiversity and resources themselves, then of human impacts on them. The technologies described in this chapter will help enable better management efforts. In this context, biodiversity refers not only to numbers of species (i.e., richness) in an arbitrarily defined area, but also to species abundances within that area. Sustainability refers to the maintenance of natural systems, biodiversity, and resources for the benefit of future generations. Arid-land grazing systems support human social systems and economies in regions all over the world, and can be expected to play increasingly critical roles as human populations increase. Further, grazing systems represent a nexus of natural and domesticated systems. In these systems, native biodiversity exists side by side with introduced species and populations, and in fact can benefit from them.

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