scholarly journals The importance of motivation, weapons, and foul odors in driving encounter competition in carnivores

2020 ◽  
Author(s):  
ML Allen ◽  
CC Wilmers ◽  
LM Elbroch ◽  
JM Golla ◽  
Heiko Wittmer
Keyword(s):  
Interference Competition ◽  
Current Theory ◽  
Lynx Rufus ◽  
Natural Environments ◽  
Ecological Communities ◽  
Competitive Advantages ◽  
Ecological Society ◽  
Strategic Behaviors ◽  
Species Specific ◽  
Occurrence Patterns

© 2016 by the Ecological Society of America. Encounter competition is interference competition in which animals directly contend for resources. Ecological theory predicts the trait that determines the resource holding potential (RHP), and hence the winner of encounter competition, is most often body size or mass. The difficulties of observing encounter competition in complex organisms in natural environments, however, has limited opportunities to test this theory across diverse species. We studied the outcome of encounter competition contests among mesocarnivores at deer carcasses in California to determine the most important variables for winning these contests. We found some support for current theory in that body mass is important in determining the winner of encounter competition, but we found that other factors including hunger and species-specific traits were also important. In particular, our top models were "strength and hunger" and "size and hunger," with models emphasizing the complexity of variables influencing outcomes of encounter competition. In addition, our wins above predicted (WAP) statistic suggests that an important aspect that determines the winner of encounter competition is species-specific advantages that increase their RHP, as bobcats (Lynx rufus) and spotted skunks (Spilogale gracilis) won more often than predicted based on mass. In complex organisms, such as mesocarnivores, species-specific adaptations, including strategic behaviors, aggressiveness, and weapons, contribute to competitive advantages and may allow certain species to take control or defend resources better than others. Our results help explain how interspecific competition shapes the occurrence patterns of species in ecological communities.

scholarly journals The importance of motivation, weapons, and foul odors in driving encounter competition in carnivores

2020 ◽  
Author(s):  
ML Allen ◽  
CC Wilmers ◽  
LM Elbroch ◽  
JM Golla ◽  
Heiko Wittmer
Keyword(s):  
Interference Competition ◽  
Current Theory ◽  
Lynx Rufus ◽  
Natural Environments ◽  
Ecological Communities ◽  
Competitive Advantages ◽  
Ecological Society ◽  
Strategic Behaviors ◽  
Species Specific ◽  
Occurrence Patterns

© 2016 by the Ecological Society of America. Encounter competition is interference competition in which animals directly contend for resources. Ecological theory predicts the trait that determines the resource holding potential (RHP), and hence the winner of encounter competition, is most often body size or mass. The difficulties of observing encounter competition in complex organisms in natural environments, however, has limited opportunities to test this theory across diverse species. We studied the outcome of encounter competition contests among mesocarnivores at deer carcasses in California to determine the most important variables for winning these contests. We found some support for current theory in that body mass is important in determining the winner of encounter competition, but we found that other factors including hunger and species-specific traits were also important. In particular, our top models were "strength and hunger" and "size and hunger," with models emphasizing the complexity of variables influencing outcomes of encounter competition. In addition, our wins above predicted (WAP) statistic suggests that an important aspect that determines the winner of encounter competition is species-specific advantages that increase their RHP, as bobcats (Lynx rufus) and spotted skunks (Spilogale gracilis) won more often than predicted based on mass. In complex organisms, such as mesocarnivores, species-specific adaptations, including strategic behaviors, aggressiveness, and weapons, contribute to competitive advantages and may allow certain species to take control or defend resources better than others. Our results help explain how interspecific competition shapes the occurrence patterns of species in ecological communities.

scholarly journals Dynamic population stage structure due to juvenile–adult asymmetry stabilizes complex ecological communities

2021 ◽  
Vol 118 (21) ◽  
pp. e2023709118
Author(s):  
André M. de Roos
Keyword(s):  
Self Regulation ◽  
Interaction Network ◽  
Population Level ◽  
Stage Structure ◽  
Current Theory ◽  
Species Interaction ◽  
Interaction Matrix ◽  
Foraging Efficiency ◽  
Ecological Communities ◽  
The Stability

Natural ecological communities are diverse, complex, and often surprisingly stable, but the mechanisms underlying their stability remain a theoretical enigma. Interactions such as competition and predation presumably structure communities, yet theory predicts that complex communities are stable only when species growth rates are mostly limited by intraspecific self-regulation rather than by interactions with resources, competitors, and predators. Current theory, however, considers only the network topology of population-level interactions between species and ignores within-population differences, such as between juvenile and adult individuals. Here, using model simulations and analysis, I show that including commonly observed differences in vulnerability to predation and foraging efficiency between juvenile and adult individuals results in up to 10 times larger, more complex communities than observed in simulations without population stage structure. These diverse communities are stable or fluctuate with limited amplitude, although in the model only a single basal species is self-regulated, and the population-level interaction network is highly connected. Analysis of the species interaction matrix predicts the simulated communities to be unstable but for the interaction with the population-structure subsystem, which completely cancels out these instabilities through dynamic changes in population stage structure. Common differences between juveniles and adults and fluctuations in their relative abundance may hence have a decisive influence on the stability of complex natural communities and their vulnerability when environmental conditions change. To explain community persistence, it may not be sufficient to consider only the network of interactions between the constituting species.

scholarly journals The return to water in ancestral Xenopus was accompanied by a novel mechanism for producing and shaping vocal signals

2018 ◽  
Author(s):  
Ursula Kwong-Brown ◽  
Martha L. Tobias ◽  
Damian O. Elias ◽  
Ian C. Hall ◽  
Coen P.H. Elemans ◽  
...  
Keyword(s):  
Sound Production ◽  
Neuromuscular Control ◽  
Current Theory ◽  
Species Divergence ◽  
Species Identity ◽  
Rapid Separation ◽  
Resonance Modes ◽  
Acoustic Signature ◽  
Vocal Signals ◽  
Species Specific

AbstractSpecies-specific vocal signals allow listeners to locate potential mates. During the tetrapod transition from water to land, lungs replaced gills, allowing expiration to drive sound production. Several groups, e.g. cetaceans and some frogs, then returned to water. Here we explore how air-driven sound production changed upon re-entry and how essential acoustic information on species identity was preserved in the secondarily aquatic frog Xenopus. We filmed movements of cartilage and muscles during evoked sound production in isolated larynges. Our results refute the current theory for Xenopus vocalization, cavitation, and instead favor sound production by mechanical excitation of laryngeal resonance modes following rapid separation of laryngeal arytenoid discs. The resulting frequency resonance modes (dyads) are intrinsic to the larynx rather than due to neuromuscular control. We show that dyads are a distinctive acoustic signature across species. While dyad component frequencies overlap across species, their ratio is shared within each Xenopus clade and thus provide information on species identity, potentially facilitating both conspecific localization and ancient species divergence.

scholarly journals Improving herpetological surveys in eastern North America using the environmental DNA method

Genome ◽  
2016 ◽  
Vol 59 (11) ◽  
pp. 991-1007 ◽  
Author(s):  
Anaïs Lacoursière-Roussel ◽  
Yohann Dubois ◽  
Eric Normandeau ◽  
Louis Bernatchez
Keyword(s):  
Large Scale ◽  
Habitat Type ◽  
Environmental Dna ◽  
Conservation Strategies ◽  
Natural Environments ◽  
Detection Rates ◽  
Survey Tool ◽  
Declining Species ◽  
Species Specific ◽  
Wood Turtle

Among vertebrates, herpetofauna has the highest proportion of declining species. Detection of environmental DNA (eDNA) is a promising method towards significantly increasing large-scale herpetological conservation efforts. However, the integration of eDNA results within a management framework requires an evaluation of the efficiency of the method in large natural environments and the calibration of eDNA surveys with the quantitative monitoring tools currently used by conservation biologists. Towards this end, we first developed species-specific primers to detect the wood turtle (Glyptemys insculpta) a species at risk in Canada, by quantitative PCR (qPCR). The rate of eDNA detection obtained by qPCR was also compared to the relative abundance of this species in nine rivers obtained by standardized visual surveys in the Province of Québec (Canada). Second, we developed multi-species primers to detect North American amphibian and reptile species using eDNA metabarcoding analysis. An occurrence index based on the distribution range and habitat type was compared with the eDNA metabarcoding dataset from samples collected in seven lakes and five rivers. Our results empirically support the effectiveness of eDNA metabarcoding to characterize herpetological species distributions. Moreover, detection rates provided similar results to standardized visual surveys currently used to develop conservation strategies for the wood turtle. We conclude that eDNA detection rates may provide an effective semiquantitative survey tool, provided that assay calibration and standardization is performed.

scholarly journals Evidence for large-scale effects of competition: niche displacement in Canada lynx and bobcat

2013 ◽  
Vol 280 (1773) ◽  
pp. 20132495 ◽  
Author(s):  
Michael J. L. Peers ◽  
Daniel H. Thornton ◽  
Dennis L. Murray
Keyword(s):  
Large Scale ◽  
Scale Effects ◽  
Spatial Scales ◽  
Biotic Interactions ◽  
Character Displacement ◽  
Lynx Rufus ◽  
Ecological Communities ◽  
Lynx Canadensis ◽  
Distribution Models ◽  
Canada Lynx

Determining the patterns, causes and consequences of character displacement is central to our understanding of competition in ecological communities. However, the majority of competition research has occurred over small spatial extents or focused on fine-scale differences in morphology or behaviour. The effects of competition on broad-scale distribution and niche characteristics of species remain poorly understood but critically important. Using range-wide species distribution models, we evaluated whether Canada lynx ( Lynx canadensis ) or bobcat ( Lynx rufus ) were displaced in regions of sympatry. Consistent with our prediction, we found that lynx niches were less similar to those of bobcat in areas of sympatry versus allopatry, with a stronger reliance on snow cover driving lynx niche divergence in the sympatric zone. By contrast, bobcat increased niche breadth in zones of sympatry, and bobcat niches were equally similar to those of lynx in zones of sympatry and allopatry. These findings suggest that competitively disadvantaged species avoid competition at large scales by restricting their niche to highly suitable conditions, while superior competitors expand the diversity of environments used. Our results indicate that competition can manifest within climatic niche space across species’ ranges, highlighting the importance of biotic interactions occurring at large spatial scales on niche dynamics.

scholarly journals Community Assembly and Co-occurrence Patterns Underlying the Core and Satellite Bacterial Sub-communities in the Tibetan Lakes

2021 ◽  
Vol 12 ◽  
Author(s):  
Qi Yan ◽  
Jianming Deng ◽  
Feng Wang ◽  
Yongqin Liu ◽  
Keshao Liu
Keyword(s):  
Community Assembly ◽  
454 Sequencing ◽  
Species Traits ◽  
Rrna Gene ◽  
Natural Environments ◽  
Ecological Processes ◽  
The Core ◽  
Core Species ◽  
Occurrence Patterns ◽  
Satellite Species

Microbial communities normally comprise a few core species and large numbers of satellite species. These two sub-communities have different ecological and functional roles in natural environments, but knowledge on the assembly processes and co-occurrence patterns of the core and satellite species in Tibetan lakes is still sparse. Here, we investigated the ecological processes and co-occurrence relationships of the core and satellite bacterial sub-communities in the Tibetan lakes via 454 sequencing of 16S rRNA gene. Our studies indicated that the core and satellite bacterial sub-communities have similar dominant phyla (Proteobacteria, Bacteroidetes, and Actinobacteria). But the core sub-communities were less diverse and exhibited a stronger distance-decay relationship than the satellite sub-communities. In addition, topological properties of nodes in the network demonstrated that the core sub-communities had more complex and stable co-occurrence associations and were primarily driven by stochastic processes (58.19%). By contrast, the satellite sub-communities were mainly governed by deterministic processes (62.17%). Overall, this study demonstrated the differences in the core and satellite sub-community assembly and network stability, suggesting the importance of considering species traits to understand the biogeographic distribution of bacterial communities in high-altitude lakes.

scholarly journals A unified model of species abundance, genetic diversity, and functional diversity reveals the mechanisms structuring ecological communities

2020 ◽  
Author(s):  
Isaac Overcast ◽  
Megan Ruffley ◽  
James Rosindell ◽  
Luke Harmon ◽  
Paulo A. V. Borges ◽  
...  
Keyword(s):  
Community Assembly ◽  
Island Biogeography ◽  
Spatial Scales ◽  
Mechanistic Model ◽  
Species Abundance ◽  
Real Data ◽  
Current Theory ◽  
Supervised Machine Learning ◽  
Ecological Communities ◽  
Trait Variation

AbstractBiodiversity accumulates hierarchically by means of ecological and evolutionary processes and feedbacks. Reconciling the relative importance of these processes is hindered by current theory, which tends to focus on a single spatial, temporal or taxonomic scale. We introduce a mechanistic model of community assembly, rooted in classic island biogeography theory, which makes temporally explicit joint predictions across three biodiversity data axes: i) species richness and abundances; ii) population genetic diversities; and iii) trait variation in a phylogenetic context. We demonstrate that each data axis captures information at different timescales, and that integrating these axes enables discriminating among previously unidentifiable community assembly models. We combine our massive eco-evolutionary synthesis simulations (MESS) with supervised machine learning to fit the parameters of the model to real data and infer processes underlying how biodiversity accumulates, using communities of tropical trees, arthropods, and gastropods as case studies that span a range of spatial scales.

scholarly journals Putative functions and co-occurrence patterns of the microbial communities in natural and engineered ecosystems

2021 ◽  
Author(s):  
Yu Xia ◽  
Na Li ◽  
Yiyun Chen ◽  
Weijia Li ◽  
Xuwen He ◽  
...  
Keyword(s):  
Microbial Communities ◽  
High Throughput Sequencing ◽  
Wastewater Treatment Plants ◽  
Rrna Gene ◽  
Natural Environments ◽  
Anaerobic Digesters ◽  
Network Analyses ◽  
Wb Network ◽  
Almost All ◽  
Occurrence Patterns

Abstract Understanding functions and co-occurrence patterns of microbial communities in various ecosystems enriches the knowledge on ecosystem characteristics and microbial ecology. However, such analyses have rarely been reported. Herein, functions and inter-taxa correlations of microbial communities in a set of natural environments (farmland (SA), forest soil (SB) and Caspian Sea sediments (CSS)) and engineered ecosystems (wastewater treatment plants (FW, WA and WB) and anaerobic digesters (AD)) were studied based on FAPROTAX and network analyses, respectively, by a collection of 115 samples from seven published 16S rRNA gene datasets generated by high-throughput sequencing. The results show that chemoheterotrophy related populations were the most abundant in almost all the communities. Their relative abundances (RAs) in the AD systems were the highest (43.7%±4.2%), followed by those of the soil environments (40.2%±1.9% in SA and 36.4%±2.0% in SB). For each ecosystem, the indicative community and overall community showed differentiations in several function categories. For example, the SA and SB indicative communities showed higher RAs in aerobic chemoheterotrophy, the CSS indicative community showed higher RAs in sulfate respiration, the AD indicative community showed higher RAs in fermentation, and the WB indicative community included higher RAs of predatory/exoparasitic bacteria. Three molecular ecological networks of the communities from the AD, WB and SB datasets were constructed, respectively. The WB network showed the highest proportion of negative correlations (70.4%), possibly attributed to the environmental pressure which aggravated microbial competition. The positively correlated taxa showed lower phylogenetic distances than the negatively correlated taxa on average in each network.

Mutual exclusion of congeneric monogenean species in a space-limited habitat

Parasitology ◽  
1998 ◽  
Vol 117 (6) ◽  
pp. 563-569 ◽  
Author(s):  
J. A. JACKSON ◽  
R. C. TINSLEY ◽  
H. H. HINKEL
Keyword(s):  
Urinary Bladder ◽  
Interference Competition ◽  
Mutual Exclusion ◽  
Single Species ◽  
Species Pairs ◽  
In Captivity ◽  
Concurrent Infections ◽  
Host Genetic ◽  
Random Distributions ◽  
Species Specific

Adults of the monogenean genus Protopolystoma infecting Xenopus species occur in an extremely space-limited habitat, the urinary bladder. Xenopus wittei, from a population in Rwanda naturally infected with Protopolystoma fissilis and Protopolystoma simplicis, were exposed to reinfection in captivity (for 1–3 months post-capture) and then monitored in the laboratory for up to 5 months in transmission-free conditions. The two parasites co-occurred in individual bladders less frequently than expected if they were dispersed randomly. Distribution of bladder infections was significantly non-independent (n=157) and gravid worms of both species were never found in the same host. This pattern might be explained by interference competition between the parasites or by genetic differences in susceptibility within the host species, which is of allopolyploid origin. Other distributional data for sympatric polystomatid species pairs, including P. fissilis and P. ramulosus, show concurrent infections at frequencies consistent with random distributions (i.e. no evidence of interspecific competition or variability in species-specific susceptibility of the hosts). Interference between P. fissilis and P. simplicis (assuming host genetic factors are not involved) may therefore result from a mechanism specific to this species pair. Observations on infection turnover in captive hosts suggest that loss of adult worms may be related to the arrival of juveniles (of either species) in the urinary bladder. Ectopic infection of the host urinary ducts by adult and subadult P. fissilis was observed in some single-species infestations and may be density related. However, the use of an ectopic-site ‘refugium’ has never been observed in concurrent polystomatid infections.

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