scholarly journals The far-reaching ecological effects of genetic fitness in a keystone predator species, grey wolves

2021 ◽  
Author(s):  
Sarah Hoy ◽  
Philip Hedrick ◽  
Rolf Peterson ◽  
Leah Vucetich ◽  
Kristin Brzeski ◽  
...  
Keyword(s):  
Keystone Species ◽  
Predation Rate ◽  
Predator Population ◽  
Important Species ◽  
Predator Species ◽  
Keystone Predator ◽  
Isle Royale National Park ◽  
Large Fluctuations ◽  
Mammalian Herbivore ◽  
Genetic Fitness

Although loss of genetic fitness is known to be severely detrimental to the viability of populations, little is known about how changes in the genetic fitness of keystone species can impact the functioning of communities and ecosystems. Here we assessed how changes in the genetic fitness of a keystone predator, grey wolves, impacted the ecosystem of Isle Royale National Park over 2-decades. The decline and subsequent resurgence of inbreeding in the wolf population led to a rise and then fall in predation rates on moose, the primary prey of wolves and dominant mammalian herbivore in this system. Those changes in predation rate led to large fluctuations in moose abundance which in turn impacted browse rates on balsam fir, the dominant forage for moose during winter and an important species in the forest. Thus, forest dynamics can be traced back to changes in the genetic health of a predator population.

scholarly journals Risk Assessment for Key Socio-Economic and Ecological Species in a Sub-Arctic Marine Ecosystem Under Combined Ocean Acidification and Warming

Ecosystems ◽  
2021 ◽  
Author(s):  
Maartje Oostdijk ◽  
Erla Sturludóttir ◽  
Maria J. Santos
Keyword(s):  
Ocean Acidification ◽  
Atlantic Cod ◽  
Marine Ecosystem ◽  
Keystone Species ◽  
Ecosystem Model ◽  
The Arctic ◽  
Predatory Fish ◽  
Important Species ◽  
Cascading Effects ◽  
Icelandic Waters

AbstractThe Arctic may be particularly vulnerable to the consequences of both ocean acidification (OA) and global warming, given the faster pace of these processes in comparison with global average speeds. Here, we use the Atlantis ecosystem model to assess how the trophic network of marine fishes and invertebrates in the Icelandic waters is responding to the combined pressures of OA and warming. We develop an approach where we first identify species by their economic (catch value), social (number of participants in fisheries), or ecological (keystone species) importance. We then use literature-determined ranges of sensitivity to OA and warming for different species and functional groups in the Icelandic waters to parametrize model runs for different scenarios of warming and OA. We found divergent species responses to warming and acidification levels; (mainly) planktonic groups and forage fish benefited while (mainly) benthic groups and predatory fish decreased under warming and acidification scenarios. Assuming conservative harvest rates for the largest catch-value species, Atlantic cod, we see that the population is projected to remain stable under even the harshest acidification and warming scenario. Further, for the scenarios where the model projects reductions in biomass of Atlantic cod, other species in the ecosystem increase, likely due to a reduction in competition and predation. These results highlight the interdependencies of multiple global change drivers and their cascading effects on trophic organization, and the continued high abundance of an important species from a socio-economic perspective in the Icelandic fisheries.

scholarly journals Cultural keystone species of fauna as a method for assessing conservation priorities in a Protected Area of the Brazilian semiarid

2016 ◽  
Vol 16 (2) ◽  
Author(s):  
Kallyne Machado Bonifácio ◽  
Eliza Maria Xavier Freire ◽  
Alexandre Schiavetti
Keyword(s):  
Food Preference ◽  
Keystone Species ◽  
Conservation Priorities ◽  
Structured Interviews ◽  
Important Species ◽  
Cultural Importance ◽  
Brazilian Semiarid ◽  
Use Values ◽  
Environmental Protection Area ◽  
Protection Area

The Cultural Keystone Species (CKS) method of identification has been used to define culturally important species. The objective of this study was to identify and characterize CKS vertebrates in the communities surrounding the Environmental Protection Area of Chapada do Araripe and define conservation priorities using semi-structured interviews and free listings. Interviews were conducted with 246 people; 53 species were identified and then included in categories of use: food, medicinal, handicraft and symbolic. Food preference was identified for Mazama gouazoubira, Penelope superciliaris, Dasyprocta prymnolopha and Dasypus novencimctus. As medicinal resources, Salvator merianae and M. gouazoubira represented 51.85% of treatment recommendations. For use in handicrafts, M. gouazoubira, which is also the only species recorded for symbolic use, stands out. Use values (UV) varied from 0.03 to 1.34, and M. gouazoubira had the highest UV (1.34) and a 0.74 projection. Regarding cultural importance, M. gouazoubira was the species with the highest UV and projection, and was indicated as a CKS to be prioritized in research and conservation studies.

scholarly journals Intra-guild vs extra-guild prey: effect on predator fitness and preference of Amblyseius swirskii (Athias-Henriot) and Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae)

2009 ◽  
Vol 100 (2) ◽  
pp. 167-173 ◽  
Author(s):  
R. Buitenhuis ◽  
L. Shipp ◽  
C. Scott-Dupree
Keyword(s):  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Predation Rate ◽  
Predatory Mites ◽  
Amblyseius Swirskii ◽  
Neoseiulus Cucumeris ◽  
Predator Species ◽  
Flower Thrips ◽  
Fast Development ◽  
High Predation Rate

AbstractThe relationships between the predatory mites, Amblyseius swirskii (Athias-Henriot) and Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae), and their prey, western flower thrips (Frankliniella occidentalis Pergande) (Thysanoptera: Thripidae), were investigated to determine the effects of predation on intra-guild or extra-guild prey and predator preference. Life history characteristics of both predatory mites were measured when fed eggs and larvae of the other predator species and compared to data obtained when the predators were fed thrips larvae. In addition, choice tests were conducted to determine if the predators had a preference for different prey or if they were indiscriminate predators. Amblyseius swirskii appears to be an important intra-guild predator of N. cucumeris juveniles because of a high predation rate and a preference for N. cucumeris juveniles over thrips. Neoseiulus cucumeris is also an intra-guild predator of A. swirskii juveniles; however, it has a lower predation rate than A. swirskii. Contrary to intra-guild predation theory, intra-guild prey was an equally good or better food source than thrips (extra-guild prey) for both predators, based on high oviposition rates and fast development times. The results of this study indicate a high potential for negative interactions between A. swirskii and N. cucumeris when used together in biological control of thrips.

scholarly journals Trophic relationships between predators, whiteflies and their parasitoids in tomato greenhouses: a molecular approach

2012 ◽  
Vol 102 (4) ◽  
pp. 415-423 ◽  
Author(s):  
R. Moreno-Ripoll ◽  
R. Gabarra ◽  
W.O.C. Symondson ◽  
R.A. King ◽  
N. Agustí
Keyword(s):  
Biological Control ◽  
Molecular Detection ◽  
Dna Detection ◽  
Pcr Primers ◽  
Predation Rate ◽  
Trialeurodes Vaporariorum ◽  
Trophic Relationships ◽  
Predator Species ◽  
Eretmocerus Mundus ◽  
Species Specific

AbstractThe whitefliesBemisia tabaciGennadius andTrialeurodes vaporariorum(Westwood) (Hemiptera: Aleyrodidae) are two of the main pests in tomato crops. Their biological control in Mediterranean IPM systems is based on the predatorsMacrolophus pygmaeus(Rambur) andNesidiocoris tenuisReuter (Hemiptera: Miridae), as well as on the parasitoidsEretmocerus mundus(Mercet) andEncarsia pergandiellaHoward (Hymenoptera: Aphelinidae). These natural enemies may interact with each other and their joint use could interfere with the biological control of those whitefly pests. Analysis of predator-prey interactions under field conditions is therefore essential in order to optimize whitefly control. Species-specific polymerase chain reaction (PCR)-primers were designed to detect DNA fragments of these whiteflies and parasitoids within both predator species in tomato greenhouses. We demonstrated that both predators feed on both whitefly species, as well as on both parasitoids under greenhouse conditions. Prey molecular detection was possible where prey abundance was very low or even where predation was not observed under a microscope. Whitefly DNA detection was positively correlated with adult whitefly abundance in the crop. However, a significant relationship was not observed between parasitoid DNA detection and the abundance of parasitoid pupae, even though the predation rate on parasitoids was high. This unidirectional intraguild predation (predators on parasitoids) could potentially reduce their combined impact on their joint prey/host. Prey molecular detection provided improved detection of prey consumption in greenhouse crops, as well as the possibility to identify which prey species were consumed by each predator species present in the greenhouse, offering a blueprint with wider applicability to other food webs.

Predation on simulated duck nests in relation to nest density and landscape structure

2010 ◽  
Vol 37 (7) ◽  
pp. 597 ◽  
Author(s):  
Eliška Padyšáková ◽  
Martin Šálek ◽  
Lukáš Poledník ◽  
František Sedláček ◽  
Tomáš Albrecht
Keyword(s):  
Survival Rates ◽  
Predation Rate ◽  
High Density ◽  
Nest Density ◽  
Predator Species ◽  
Density Dependent ◽  
Landscape Type ◽  
Mammalian Predators ◽  
Littoral Vegetation ◽  
Nest Predator

Context Density-dependent predation has been recently discussed as a contributing cause of duck nest failure. Aims We tested whether nest density increases the nest predation rate (density-dependent predation) in patches of littoral vegetation surrounding fishponds in two contrasting landscape types, the first dominated by forest and the other dominated by agricultural fields. Methods In total, 576 simulated ground nests were deployed in 48 littoral patches in South Bohemia, Czech Republic, in two replicates (June and July), for two consecutive years (2005 and 2006). Nests were deployed either solitarily (low-density plots) or in groups of five nests (high-density plots). Key results Despite differences in local predator communities, we found no evidence of different survival rates of solitary nests and nests placed in high-density patches in either habitat. Mammalian predators were the most common nest predators, followed by birds. The composition of nest predator community depended on landscape type, with mammals predominating in forest landscape and birds in agricultural areas. Our data thus do not support the theory of density-dependent predation of duck nests in littoral patches, regardless of predominant nest predator type. Conclusions Based on our results, we conclude that nest predator responses to different habitats are complex, taxon specific, and context dependent. Implications Conservation efforts for waterfowl may need to be customised according to the nest-predator species primarily responsible for local nest mortality and the nature of the landscape mosaic.

scholarly journals Ocean Acidification and Increased Temperature Have Both Positive and Negative Effects on Early Ontogenetic Traits of a Rocky Shore Keystone Predator Species

PLoS ONE ◽  
2016 ◽  
Vol 11 (3) ◽  
pp. e0151920 ◽  
Author(s):  
Patricio H. Manríquez ◽  
María Elisa Jara ◽  
Mylene E. Seguel ◽  
Rodrigo Torres ◽  
Emilio Alarcon ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Rocky Shore ◽  
Negative Effects ◽  
Predator Species ◽  
Keystone Predator ◽  
Increased Temperature

scholarly journals Human–carnivore conflict around Pendjari Biosphere Reserve, northern Benin

Oryx ◽  
2011 ◽  
Vol 45 (4) ◽  
pp. 569-578 ◽  
Author(s):  
Etotépé A. Sogbohossou ◽  
Hans H. de Iongh ◽  
Brice Sinsin ◽  
Geert R. de Snoo ◽  
Paul J. Funston
Keyword(s):  
Biosphere Reserve ◽  
Predation Rate ◽  
Papio Anubis ◽  
Hunting Season ◽  
Predator Species ◽  
Individual Interviews ◽  
Close Proximity ◽  
Geographical Position ◽  
Large Predators ◽  
The Village

AbstractClose proximity between humans and large predators results in high levels of conflict. We investigated the extent of, and factors leading to, this conflict through focal group and individual interviews in all villages around Pendjari Biosphere Reserve, northern Benin. Livestock losses from 2000 to 2007 (n = 752) were reported to be mainly caused by spotted hyaena Crocuta crocuta (53.6%), baboon Papio anubis (24.8%), and lion Panthera leo (18.0%). These predators mainly predated sheep and goats (52.1%) and pigs (42.3%), with lions being the main predators of cattle (78.9%). Lion and hyaena diets were more diverse than that of baboons, which killed only small stock. The level of conflict increased during 2000–2007. Predation rate differs between predator species and is significantly influenced by month, rainfall of the month before the predation event, and length of the dry period in a year. The geographical position of the village, the distance of the village to the Park and the number of herbivores legally killed every hunting season also influenced predation intensity. Our findings suggest that improvement of husbandry techniques and education will reduce conflicts and contribute to improved conservation of these threatened predators.

Effects of multiple predator species on green treefrog (Hyla cinerea) tadpoles

2005 ◽  
Vol 83 (7) ◽  
pp. 996-1002 ◽  
Author(s):  
M S Gunzburger ◽  
J Travis
Keyword(s):  
Prey Species ◽  
Predation Rate ◽  
Microhabitat Use ◽  
Combined Effects ◽  
Predator Density ◽  
Hyla Cinerea ◽  
Predator Species ◽  
Multiple Predators ◽  
Multiple Predator Species ◽  
Green Treefrog

Prey species that occur across a range of habitats may be exposed to variable communities of multiple predator species across habitats. Predicting the combined effects of multiple predators can be complex. Many experiments evaluating the effects of multiple predators on prey confound either variation in predator density with predator identity or variation in relative predator frequency with overall predation rates. We develop a new experimental design of factorial predator combinations that maintains a constant expected predation rate, under the null hypothesis of additive predator effects. We implement this design to evaluate the combined effects of three predator species (bass, aeshnid and libellulid odonate naiads) on mortality rate of a prey species, Hyla cinerea (Schneider, 1799) tadpoles, that occurs across a range of aquatic habitats. Two predator treatments (libellulid and aeshnid + libellulid) resulted in lower tadpole mortality than any of the other predator treatments. Variation in tadpole mortality across treatments was not related to coarse variation in microhabitat use, but was likely due to intraguild predation, which occurred in all predator treatments. Hyla cinerea tadpoles have constant, low survival values when exposed to many different combinations of predator species, and predation rate probably increases linearly with predator density.

The effect of adaptive change in the prey on the dynamics of an exploited predator population

2005 ◽  
Vol 62 (4) ◽  
pp. 758-766 ◽  
Author(s):  
Peter A Abrams ◽  
Hiroyuki Matsuda
Keyword(s):  
Prey Species ◽  
Maximum Size ◽  
Reproductive Rate ◽  
Small Range ◽  
Predator Population ◽  
Predator Species ◽  
Harvest Rate ◽  
Stock Size ◽  
Risk Of Predation ◽  
The Relationship

Mathematical models examine the relationship between harvesting effort and stock size for a predator species when the prey adapts to the risk of predation. In one set of models, the prey can increase its own reproductive rate if it increases its vulnerability to the predator. In the second set of models, each of two prey species has fixed characteristics, but changes in the average characteristics within the prey trophic level occur via shifts in the relative abundance of the two species. In both models, the equilibrium predator population can increase as harvest of that species increases. In the case of two-prey models, the predator's equilibrium population always increases with an increased harvest rate if the two prey coexist and share a single resource. The predator's equilibrium population often decreases from its maximum size to zero over a very small range of harvest rates, once those rates become high enough. Because increased stock size is often used to justify increased harvest rates, this relationship poses a risk that harvest rate will increase to the point where the stock quickly collapses. The results are relevant to understanding changes in the population size of a species experiencing declining environmental conditions.

Analysis of a harvested tritrophic food chain model in the presence of additional food for top predator

2018 ◽  
Vol 11 (04) ◽  
pp. 1850059 ◽  
Author(s):  
Prabir Panja ◽  
Swarup Poria ◽  
Shyamal Kumar Mondal
Keyword(s):  
Extinction Risk ◽  
Predation Rate ◽  
Optimal Harvesting ◽  
Chain Model ◽  
Predator Population ◽  
Top Predator ◽  
Additional Food ◽  
Revenue Collection ◽  
Existence And Stability ◽  
Food Chain Model

In this paper, we propose and analyze a three-species predator–prey system in the presence of additional food for top predator. It is assumed that the middle predator is acting as a prey as well as a predator and the top predator consumes both prey as well as middle predator. It is also considered that a constant amount of additional food for top predator exists in the ecosystem. The effects of harvesting of top predator are investigated. The existence and stability conditions of the equilibria have been discussed analytically. The Hopf bifurcation analysis of the system with respect to predation rate of prey to the top predator and the harvesting effort have been analyzed both analytically and numerically. Pontryagin’s maximum principle is used to determine the optimal harvesting of top predator population to maximize the discounted net revenue. From our analysis, it is seen that the additional food has a significant impact to prevent the extinction risk of top predator population and also to increase revenue collection. Finally, some numerical results have been given in support of our analytical findings.

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