Distribution patterns of vertebrate and invertebrate planktivores in Newfoundland lakes with evidence of predator–prey and competitive interactions

1990 ◽  
Vol 68 (7) ◽  
pp. 1559-1567 ◽  
Author(s):  
Christine E. Campbell ◽  
Roy Knoechel
Keyword(s):  
Gasterosteus Aculeatus ◽  
Spatial Separation ◽  
Distribution Patterns ◽  
Competitive Interactions ◽  
Cyclopoid Copepod ◽  
Predator Prey ◽  
Interacting Species ◽  
Leptodora Kindtii ◽  
Faunal Diversity ◽  
Avalon Peninsula

The vertebrate Gasterosteus aculeatus, the threespine stickleback, and the invertebrates Chaoborus punctipennis, Chaoborus trivittatus, and Leptodora kindtii are the major predators of zooplankton in lakes on the Avalon Peninsula, Newfoundland. Predator–prey and competitive interactions among these planktivores are potentially strong. Low faunal diversity in the lakes limits the number of interacting species, which may increase the intensity of the interactions, while the low habitat heterogeneity of the lakes decreases the probability of spatial separation of species to increase rates of species encounters. Analyses of distributional patterns (presence or absence data) of the planktivores in 15 Avalon lakes indicated that the distributions of both Chaoborus spp. were significantly and negatively related to the distribution of sticklebacks. Chaoborus densities were significantly higher in the lakes without sticklebacks. Sticklebacks were observed to eat third and fourth instars of both Chaoborus species in laboratory experiments and hence, through predation, may be able to exclude these species from some lakes. There was no significant relationship between the distributions of Leptodora and sticklebacks or between Leptodora and C. punctipennis, however the distributions of Leptodora and C. trivittatus were significantly and negatively related, indicating a possible competitive interaction. Environmental factors also influence planktivore distribution and abundance: a principal components factor derived from planktivore density data was significantly correlated with cyclopoid copepod biomass, lake SO4 levels, and lake surface area (multiple linear regression, r2 = 0.71).

scholarly journals Long-term UVB exposure promotes predator-inspection behaviour in a fish

2017 ◽  
Vol 13 (12) ◽  
pp. 20170497 ◽  
Author(s):  
Simon Vitt ◽  
Janina E. Zierul ◽  
Theo C. M. Bakker ◽  
Ingolf P. Rick
Keyword(s):  
Gasterosteus Aculeatus ◽  
Stratospheric Ozone ◽  
Ultraviolet B ◽  
Antipredator Behaviour ◽  
Uvb Radiation ◽  
Ecological Processes ◽  
Predator Prey ◽  
Natural Sunlight ◽  
Predator Inspection

Ultraviolet-B radiation (UVB) reaching the earth's surface has increased due to human-caused stratospheric ozone depletion. Whereas the harmful effects of UVB on aquatic organisms are well studied at the molecular and cellular level, recent studies have also begun to address behavioural changes caused by sublethal amounts of UVB. However, the behavioural consequences of long-term exposure to ecologically relevant UVB levels over several life stages are virtually unknown, particularly with regard to predator–prey behaviour. We found increased predator-inspection behaviour together with a smaller body length in three-spined sticklebacks ( Gasterosteus aculeatus ) after fish were exposed for about seven months to natural sunlight conditions with enhanced UVB, compared with full siblings exposed to natural sunlight only. The observed change in antipredator behaviour may reflect a direct behavioural response mediated through UVB-induced oxidative stress during development. Alternatively, the smaller body size in UVB-exposed fish may result in an increased inspection effort allowing them to spend more time foraging. Our findings suggest that, within the scope of environmental change, UVB radiation constitutes an important stress factor by eliciting behavioural responses that influence crucial ecological processes, such as predator–prey interactions.

The saltmarsh vegetation of the lower Berg River

Bothalia ◽  
1994 ◽  
Vol 24 (2) ◽  
pp. 223-228
Author(s):  
M. O'Callaghan
Keyword(s):  
Sea Level ◽  
Species Distribution ◽  
Distribution Patterns ◽  
Competitive Interactions ◽  
Tidal Inundation ◽  
Mean Sea Level ◽  
Irregular Distribution ◽  
Vegetation Species

The lower Berg River supports approximately 250 ha of estuarine saltmarsh vegetation. Species distribution patterns, as sampled along six transects, are described. Elevation above mean sea level (MSL) is proposed as a strong determinant of these patterns. However, there are no typical patterns. The patchy and irregular distribution patterns possibly result from an inconsistent relationship between species distribution and salinity, tidal inundation and/or competitive interactions.

scholarly journals Evolution in interacting species alters predator life-history traits, behaviour and morphology in experimental microbial communities

2020 ◽  
Vol 287 (1928) ◽  
pp. 20200652
Author(s):  
Johannes Cairns ◽  
Felix Moerman ◽  
Emanuel A. Fronhofer ◽  
Florian Altermatt ◽  
Teppo Hiltunen
Keyword(s):  
Life History ◽  
Prey Species ◽  
Rapid Evolution ◽  
Prey Type ◽  
Automated Image Analysis ◽  
Foraging Efficiency ◽  
Predator Prey ◽  
Evolving Systems ◽  
Interacting Species ◽  
Evolutionary Response

Predator–prey interactions heavily influence the dynamics of many ecosystems. An increasing body of evidence suggests that rapid evolution and coevolution can alter these interactions, with important ecological implications, by acting on traits determining fitness, including reproduction, anti-predatory defence and foraging efficiency. However, most studies to date have focused only on evolution in the prey species, and the predator traits in (co)evolving systems remain poorly understood. Here, we investigated changes in predator traits after approximately 600 generations in a predator–prey (ciliate–bacteria) evolutionary experiment. Predators independently evolved on seven different prey species, allowing generalization of the predator's evolutionary response. We used highly resolved automated image analysis to quantify changes in predator life history, morphology and behaviour. Consistent with previous studies, we found that prey evolution impaired growth of the predator, although the effect depended on the prey species. By contrast, predator evolution did not cause a clear increase in predator growth when feeding on ancestral prey. However, predator evolution affected morphology and behaviour, increasing size, speed and directionality of movement, which have all been linked to higher prey search efficiency. These results show that in (co)evolving systems, predator adaptation can occur in traits relevant to foraging efficiency without translating into an increased ability of the predator to grow on the ancestral prey type.

Bifurcation of steady-state solutions in predator-prey and competition systems

1984 ◽  
Vol 97 ◽  
pp. 21-34 ◽  
Author(s):  
J. Blat ◽  
K. J. Brown
Keyword(s):  
Steady State ◽  
Bifurcation Theory ◽  
Existence Of Solutions ◽  
Global Bifurcation ◽  
Reaction Diffusion ◽  
Reaction Diffusion Equations ◽  
Predator Prey ◽  
Interacting Species ◽  
Global Bifurcation Theory ◽  
Steady State Solutions

SynopsisWe discuss steady-state solutions of systems of semilinear reaction-diffusion equations which model situations in which two interacting species u and v inhabit the same bounded region. It is easy to find solutions to the systems such that either u or v is identically zero; such solutions correspond to the case where one of the species is extinct. By using decoupling and global bifurcation theory techniques, we prove the existence of solutions which are positive in both u and v corresponding to the case where the populations can co-exist.

Spatial distribution patterns of larval cytotypes of the Simulium venustum/verecundum complex (Diptera: Simuliidae) on the Avalon Peninsula, Newfoundland: factors associated with cytotype abundance and composition

1992 ◽  
Vol 70 (7) ◽  
pp. 1389-1396 ◽  
Author(s):  
J. W. McCreadie ◽  
M. H. Colbo
Keyword(s):  
Drainage Basin ◽  
Principal Component ◽  
Distribution Patterns ◽  
Restricted Gene Flow ◽  
Regression Analyses ◽  
Factors Associated ◽  
Sampling Protocols ◽  
Stream Size ◽  
Avalon Peninsula ◽  
Qualitative Changes

Using principal component analysis and cluster and regression analyses, larval macrodistribution of Simulium venustum/verecundum complex cytotypes within a drainage basin and along a stream continuum was investigated. Cytotypes included ACD (= Simulium rostratum Lundström) and AA from the verecundum line of the complex and EFG/C (= Simulium truncatum Lundström), AC(gb) and CC2-3 (combined CC2 and CC3) from the venustum line. Abundance of both AC(gb) and CC2-3 increased with increasing stream size. The abundance of CC2-3 also increased at sites with warmer temperatures and lower conductivity, dissolved oxygen, and pH levels. Cytotype composition changed in a continuous, directional, and predictable (R2 = 52.4–92.2%) manner with increased distance from outlets. It is argued that changes in cytotype composition must be considered in future sampling protocols, as quantitative and qualitative changes in the cytotype assemblage can occur over distances as short as 100 m. Discontinuity in the frequency of the IIL-4 polymorphism suggested restricted gene flow due to limited adult AA dispersal over distances greater than 12 km.

scholarly journals The cost of attack in competing networks

2015 ◽  
Vol 12 (112) ◽  
pp. 20150770 ◽  
Author(s):  
B. Podobnik ◽  
D. Horvatic ◽  
T. Lipic ◽  
M. Perc ◽  
J. M. Buldú ◽  
...  
Keyword(s):  
Real World ◽  
Conservation Law ◽  
Feedback Mechanism ◽  
Competitive Interactions ◽  
Predator Prey ◽  
Network Competition ◽  
Optimal Duration ◽  
Target Network ◽  
Negative Impacts ◽  
The Cost

Real-world attacks can be interpreted as the result of competitive interactions between networks, ranging from predator–prey networks to networks of countries under economic sanctions. Although the purpose of an attack is to damage a target network, it also curtails the ability of the attacker, which must choose the duration and magnitude of an attack to avoid negative impacts on its own functioning. Nevertheless, despite the large number of studies on interconnected networks, the consequences of initiating an attack have never been studied. Here, we address this issue by introducing a model of network competition where a resilient network is willing to partially weaken its own resilience in order to more severely damage a less resilient competitor. The attacking network can take over the competitor's nodes after their long inactivity. However, owing to a feedback mechanism the takeovers weaken the resilience of the attacking network. We define a conservation law that relates the feedback mechanism to the resilience dynamics for two competing networks. Within this formalism, we determine the cost and optimal duration of an attack, allowing a network to evaluate the risk of initiating hostilities.

scholarly journals Diversity and distribution of mollusks at three zones of mangrove in Pejarakan, Bali, Indonesia

2020 ◽  
Vol 21 (10) ◽  
Author(s):  
I KETUT GINANTRA ◽  
I KETUT MUKSIN ◽  
IDA BAGUS MADE SUASKARA ◽  
MARTIN JONI
Keyword(s):  
Mangrove Forest ◽  
Forest Conservation ◽  
Distribution Patterns ◽  
Wiener Index ◽  
Dominance Index ◽  
Mangrove Species ◽  
Mangrove Area ◽  
Faunal Diversity ◽  
Morisita Index ◽  
Number Of Individuals

Abstract. Ginantra IK, Muksin IK, Suaskara IBM, Joni M. 2020. Diversity and distribution of mollusks at three zones of mangrove in Pejarakan, Bali, Indonesia. Biodiversitas 21: 4636-4643. The diversity of mangrove species in mangrove zonations on the coast of Pejarakan plays an important role in the existence of faunal diversity, including those from mollusks. Mollusks are the dominant phylum associated with mangrove habitats, in addition to the species of the Crustacean subphylum. This research aimed to determine the diversity of mollusks and their distribution patterns in three mangrove zones in Pejarakan, Buleleng District, Bali Province, Indonesia. Data collection was conducted by establishing sampling plots across three mangrove zones, i.e. seaward zone, middle zone, and landward zone. There were 23 sampling plots in total with size of each plot was 1x1m. The species and number of individuals of each species of mollusks were recorded in each quadrat plot. The diversity of mollusks was calculated using the Shannon-Wiener index, evenness index, and dominance index, while the pattern of distribution of mollusks was measured using the Morisita index. The results of the study found 27 species of mollusks, consisting of 19 species from Gastropods group, 7 species from Bivalvia group and 1 species from Polyplacophora (chiton). The seaward zone showed the highest species diversity, while the landward zone had the lowest. Terebralia palustris had the highest abundance with 217 individuals/m2 and was distributed in the three mangrove zones. Planaxis sulcatus showed the highest abundance (87 ind./m2) in the seaward zone, and Telescopium telescopium showed a fairly high abundance and were distributed in the mid zone and the landward zone. In general, mollusks in the mangrove area of Pejarakan was distributed in a group/clustered pattern. The data from this research can serve as a reference in mangrove forest conservation efforts and mangrove forest used for ecotourism.

scholarly journals Repeatability of adaptive radiation depends on spatial scale: regional versus global replicates of stickleback in lake versus stream habitats

2019 ◽  
Author(s):  
Antoine Paccard ◽  
Dieta Hanson ◽  
Yoel E. Stuart ◽  
Frank A. von Hippel ◽  
Martin Kalbe ◽  
...  
Keyword(s):  
Adaptive Radiation ◽  
Genetic Divergence ◽  
Gasterosteus Aculeatus ◽  
Spatial Scales ◽  
Parallel Evolution ◽  
Spatial Separation ◽  
Global Scale ◽  
Freshwater Ecosystems ◽  
Geographic Scale ◽  
Genetic Constraints

ABSTRACTThe repeatability of adaptive radiation is expected to be scale dependent, with determinism decreasing as greater spatial separation among “replicates” leads to their increased genetic and ecological independence. Threespine stickleback (Gasterosteus aculeatus) provide an opportunity to test whether this expectation holds for the early stages of adaptive radiation - their diversification in freshwater ecosystems has been replicated many times. To better understand the repeatability of that adaptive radiation, we examined the influence of geographic scale on levels of parallel evolution by quantifying phenotypic and genetic divergence between lake and stream stickleback pairs sampled at regional (Vancouver Island) and global (North America and Europe) scales. We measured phenotypes known to show lake-stream divergence and used reduced representation genome-wide sequencing to estimate genetic divergence. We assessed the scale-dependence of parallel evolution by comparing effect sizes from multivariate models and also the direction and magnitude of lake-stream divergence vectors. At the phenotypic level, parallelism was greater at the regional than the global scale. At the genetic level, putative selected loci showed greater lake-stream parallelism at the regional than the global scale. Generally, the level of parallel evolution was low at both scales, except for some key univariate traits. Divergence vectors were often orthogonal, highlighting possible ecological and genetic constraints on parallel evolution at both scales. Overall, our results confirm that the repeatability of adaptive radiation decreases at increasing spatial scales. We suggest that greater environmental heterogeneity at larger scales imposes different selection regimes, thus generating lower repeatability of adaptive radiation at larger spatial scales.

Sign in / Sign up

Export Citation Format

Share Document