Intraguild predation and competition: an analysis of net growth shifts in larval amphibian prey

1988 ◽  
Vol 66 (8) ◽  
pp. 1813-1821 ◽  
Author(s):  
Spencer A. Cortwright
Keyword(s):  
Intraguild Predation ◽  
Prey Species ◽  
Negative Impact ◽  
Growth Responses ◽  
Ambystoma Jeffersonianum ◽  
Natural Pond ◽  
Resource Levels ◽  
Experimental Treatments ◽  
Salamander Larvae ◽  
Prey Populations

This study examines the net shift in prey growth among species of aquatic salamander larvae (Ambystoma) that engage in intraguild prédation and competition with their predators. Larval salamander and frog species were studied in a pen experiment in a natural pond. A 2 × 3 factorial experimental design was used. The factors were (i) the presence (11 per pen) or absence of Ambystoma opacum predators, and (ii) three levels of Ambystoma jeffersonianum (42, 84, and 168 per pen), a prey species that also shares resources with A. opacum. All other species were stocked at constant levels. Mass at metamorphosis of A. jeffersonianum was not affected by predator presence. The larval period of A. jeffersonianum (prey) decreased by 20 d in the presence of A. opacum (predators), suggesting enhanced differentiation rate when predators reduced prey populations. Ambystoma maculatum (another prey species) showed no growth responses across experimental treatments, probably because it faced predation from both A. opacum and A. jeffersonianum. A previous study showed that in the absence of both A. opacum and A. jeffersonianum predators, A. maculatum prey manifested reduced mass at metamorphosis. Thus, among these predators and prey, which share resources, the enhanced differentiation rate or larger metamorphic size that prey experienced in reduced prey populations was more important than any negative impact of depressed shared resource levels among predators and prey.

Intraguild Predation on Congeners Affects Size, Aggression, and Survival among Ambystoma Salamander Larvae

2004 ◽  
Vol 38 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Robert Brodman
Keyword(s):  
Intraguild Predation ◽  
Salamander Larvae

scholarly journals Using BAD for good: how best available data facilitated a precautionary policy change to improve protection of the prey of the tiger Panthera tigris in Malaysia

Oryx ◽  
2013 ◽  
Vol 47 (3) ◽  
pp. 420-426 ◽  
Author(s):  
Kae Kawanishi ◽  
Gopalasamy Reuben Clements ◽  
Melvin Gumal ◽  
Gareth Goldthorpe ◽  
Mohd Nawayai Yasak ◽  
...  
Keyword(s):  
Prey Species ◽  
Action Plan ◽  
Legal Protection ◽  
Camera Trapping ◽  
Panthera Tigris ◽  
Policy Changes ◽  
Illegal Hunting ◽  
Tapirus Indicus ◽  
Prey Populations

AbstractTiger Panthera tigris populations are under threat from poaching and depletion of their prey populations. The National Tiger Action Plan for Malaysia contains several actions addressing the threat of legal and illegal hunting of tiger prey species. One action in this plan required an investigation of whether urgent policy changes were needed to improve the protection of the prey of tigers, based on existing data. As the lack of reliable baseline data prevented us from determining population trends accurately, we compiled camera-trapping data from 23 studies conducted between 1997 and 2008 on four principal tiger prey species (sambar Rusa unicolor, barking deer Muntiacus muntjac, wild boar Sus scrofa and bearded pig S. barbatus) and two potential prey species (gaur Bos gaurus and Malayan tapir Tapirus indicus) and compared their distributions and relative abundances. From 10,145 wildlife photographs spanning 40,303 trap-nights, sambar, bearded pig and gaur appeared to be most threatened given their restricted distribution and low relative abundance. Among these, the gaur has full legal protection and has received more conservation attention than the other two species. Following our assessment and advocacy a 6-year moratorium on hunting both sambar and barking deer was imposed by the Malaysian government and the highest protection status possible was afforded the bearded pig. This case study illustrates how best available data (BAD), in this case from camera-trapping studies, can be harnessed to effect precautionary policy changes to curb the impacts of hunting on threatened predator and prey populations that could crash well before resources would otherwise be available for rigorous scientific assessments.

Raptor Prey Remains

2020 ◽  
Author(s):  
Ed Drewitt
Keyword(s):  
Feeding Ecology ◽  
Prey Species ◽  
Local Level ◽  
Body Parts ◽  
Change Over Time ◽  
The Common ◽  
Prey Remains ◽  
Over Time ◽  
Prey Populations

Are you curious about the remains of an animal you have found? This compilation of the most likely found body parts of animals eaten by raptors will help you identify your discovery. Including over 100 species of bird and mammal prey of raptors such as sparrowhawks, peregrines and hen harriers, this photographic guide highlights the common feathers, fur and other body parts found at raptor nests, roosts, plucking posts and other opportunistic spots. Discovering what raptors eat is an important part of confirming their feeding ecology and how this might change over time, vary on a local level or in response to changing prey populations, as well as dispelling myths and assumptions about what certain raptor species eat. Diet studies are vital for the conservation of raptor species; the more we know about what they need for survival the more we can predict and plan long-term for the protection and survival of raptors that may be vulnerable and in decline. This is the first book to show in detail the actual parts of a bird, mammal or other animal that you are likely to find in a garden, woodland or beneath a raptor roost. As more people take an interest in raptors and watch species such as peregrines via webcams and through watch groups, there is greater opportunity for finding prey remains. This book provides the first and most important step in identifying a prey species.

Top–down limits on prey populations may be more severe in larger prey species, despite having fewer predators

Ecography ◽  
2019 ◽  
Vol 42 (6) ◽  
pp. 1115-1123 ◽  
Author(s):  
Elizabeth le Roux ◽  
David G. Marneweck ◽  
Geoff Clinning ◽  
Dave J. Druce ◽  
Graham I. H. Kerley ◽  
...  
Keyword(s):  
Prey Species ◽  
Top Down ◽  
Prey Populations

scholarly journals Evidence that population increase and range expansion by Eurasian Sparrowhawks has impacted avian prey populations

2018 ◽  
Author(s):  
Christopher Paul Bell
Keyword(s):  
Range Expansion ◽  
Census Data ◽  
Prey Species ◽  
Site Occupancy ◽  
Population Increase ◽  
Substantial Impact ◽  
Bird Populations ◽  
General Decline ◽  
The Impact ◽  
Prey Populations

AbstractThe role of increased predator numbers in the general decline of bird populations in the late 20th century remains controversial, particularly in the case of the Eurasian Sparrowhawk, for which there are contradictory results concerning its effect on the abundance of potential prey species. Previous studies of breeding season census data for Sparrowhawks and prey species in Britain have measured predator abundance either as raw presence-absence data or as an estimate derived from spatially explicit modelling, and have found little evidence of association between predator and prey populations. Here, a predator index derived from site-level binary logistic modelling was used in a regression analysis of breeding census data on 42 prey species, with significant effects emerging in 27 species (16 positive, 11 negative). The frequency of significant positive associations may indicate the tracking of prey abundance by Sparrowhawks, which would tend to cancel out any negative predation effect on prey populations, rendering it difficult to detect using census data. If so, the negative effects that have emerged for some species may underestimate the impact of increased Sparrowhawk numbers on the prey populations concerned. Nevertheless, estimates of the effect on national populations of prey species, obtained by combining effect sizes with a measure of the increase in site occupancy by the predator, suggest the possibility of a substantial impact. It cannot, therefore, be ruled out that the increase in abundance and range expansion of Sparrowhawks made a significant contribution to contemporaneous declines in the populations of many of its prey species.

Growth of five hybrid poplar genotypes exposed to interacting elevated CO2 and O3

1998 ◽  
Vol 28 (11) ◽  
pp. 1706-1716 ◽  
Author(s):  
R E Dickson ◽  
M D Coleman ◽  
D E Riemenschneider ◽  
J G Isebrands ◽  
G D Hogan ◽  
...  
Keyword(s):  
Carbon Allocation ◽  
Negative Impact ◽  
Hybrid Poplar ◽  
Control Plant ◽  
Basal Area ◽  
Dry Mass ◽  
Atmospheric Pollutants ◽  
Growth Strategies ◽  
Growth Responses ◽  
Plant Parts

A wide variety of hybrid poplar clones are being introduced for intensive culture biomass production, but the potential clonal or genotypic response to increasing tropospheric carbon dioxide (CO2), ozone (O3), and their interactions are unknown. To study these effects, we exposed five different hybrid Populus clones to increased concentrations of CO2, O3, and CO2 + O3 in open-top chambers for one growing season and determined growth responses. Exposure to elevated CO2 increased height growth, dry mass, and basal area; exposure to O3 decreased all three of these growth responses. Exposure impact differed among the different plant parts (leaf, stem, and roots) and among the clones. These differences were associated with different growth strategies or carbon allocation patterns inherent in the different clones. The fastest growing clones had the greatest response to O3 treatment. The addition of CO2 to the O3 exposure counteracted the negative impact of O3 in all plant components except leaf mass (e.g., CO2 + O3 plant mass equaled control plant mass) in all of the clones. But correspondingly, added O3 negated increased growth from CO2. Genetic variation in response to atmospheric pollutants must be considered even in closely related genotypes found in Populus culture.

scholarly journals Photosynthetic and Growth Responses of Olive to Proline and Salicylic Acid under Salinity Condition

2016 ◽  
Vol 44 (2) ◽  
pp. 579-585 ◽  
Author(s):  
Sasan ALINIAEIFARD ◽  
Jafar HAJILOU ◽  
Seyed Jalal TABATABAEI
Keyword(s):  
Salicylic Acid ◽  
Salt Stress ◽  
Vegetative Growth ◽  
Negative Impact ◽  
Net Photosynthesis ◽  
Growth Responses ◽  
Negative Effects ◽  
Root Volume ◽  
Chlorophyll Index ◽  
Olive Trees

Salinity has a negative impact on growth and productivity of crops on agricultural lands. Since proline and salicylic acid are used by plants to cope with stress conditions, to test whether they can help olive plants to alleviate negative impacts of salt stress, an experiment was carried out by spraying proline (15 mM) and salicylic acid (0.25 mM) on the plants that subjected to two salinity levels (0 and 100 mM NaCl). Salinity caused an alteration in biomass partitioning; in such a way that shoot vegetative growth was more restricted by salinity than root vegetative growth. Root volume was increased in proline-sprayed plants while salinity caused a decline in the root volume. Salinity resulted in an increase in specific leaf area. Net photosynthesis, stomatal conductance and transpiration rate were decreased by salinity application in root medium. Peroxidase activity decreased in plants that subjected to salinity stress. However, application of proline resulted in improvement of vegetative growth in both control and salinity conditions. Increase in chlorophyll index was observed following proline application, while salinity caused a decline in chlorophyll index. In conclusion, salinity can cause deleterious effects on photosynthesis and vegetative growth of olive trees. Exogenous application of proline can help plants to cope with negative effects of salt stress on olive plants.

scholarly journals Direct and Indirect Effects of Invasive vs. Native Ant-Hemipteran Mutualism: A Meta-Analysis That Supports the Mutualism Intensity Hypothesis

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2323
Author(s):  
Bo Wang ◽  
Min Lu ◽  
Yanqiong Peng ◽  
Simon T. Segar
Keyword(s):  
Prey Species ◽  
Negative Impact ◽  
Control Strategies ◽  
Meta Analysis ◽  
Invasive Ants ◽  
Invasive Ant ◽  
Cascading Effects ◽  
Ant Predation ◽  
Ecological Dominance ◽  
Ant Control

Mutualism can facilitate the colonization, establishment, and spread of invasive species. By modifying interactions with third parties, mutualisms can have cascading community-wide effects. Both native and invasive ants are capable of forming mutualisms with hemipteran insects, preying on non-hemipteran herbivores and indirectly affecting primary production. Comparative research on the effects of both native and invasive ant exclusions on multitrophic interactions is therefore crucial for understanding the invasive potential of ants, along with any ecological consequences that invasions may have. We performed a quantitative review of the multitrophic effects of invasive and native ants on insect–plant food webs. Herbivorous insects are the most common food source for both invasive (comprising 56% of prey species caught) and native ants (55% of the prey species caught), followed by predators (31% for invasive ants, 45% for native ants). Excluding both invasive and native ants significantly reduced hemipteran abundance, and excluding invasive ants had a greater negative impact on hemipteran abundance than native ants. Native ant predation significantly reduced herbivore abundance, but excluding invasive ants had no effect. Cascading effects of native ants on plant fitness were significantly positive, but there was no significant impact of invasive ants. These findings suggest a weak relationship between the presence of invasive ants and non-hemipteran herbivore abundance. We suggest that the hemipteran–ant mutualism could represent a ‘symbiotic invasion’. The ecological dominance of invasive ants is often facilitated by hemipteran insects. This association requires invasive ant control strategies to expand beyond ants to consider mutualists.

scholarly journals Interactions between a Top Order Predator and Exotic Mesopredators in the Australian Rangelands

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Katherine E. Moseby ◽  
Heather Neilly ◽  
John L. Read ◽  
Helen A. Crisp
Keyword(s):  
Intraguild Predation ◽  
Prey Species ◽  
Red Fox ◽  
Interference Competition ◽  
South Australia ◽  
Mortality Rates ◽  
Net Benefit ◽  
Male And Female ◽  
Dominant Mechanism ◽  
Feral Cats

An increase in mesopredators caused by the removal of top-order predators can have significant implications for threatened wildlife. Recent evidence suggests that Australia’s top-order predator, the dingo, may suppress the introduced cat and red fox. We tested this relationship by reintroducing 7 foxes and 6 feral cats into a 37 km2fenced paddock in arid South Australia inhabited by a male and female dingo. GPS datalogger collars recorded locations of all experimental animals every 2 hours. Interactions between species, mortality rates, and postmortems were used to determine the mechanisms of any suppression. Dingoes killed all 7 foxes within 17 days of their introduction and no pre-death interactions were recorded. All 6 feral cats died between 20 and 103 days after release and dingoes were implicated in the deaths of at least 3 cats. Dingoes typically stayed with fox and cat carcasses for several hours after death and/or returned several times in ensuing days. There was no evidence of intraguild predation, interference competition was the dominant mechanism of suppression. Our results support anecdotal evidence that dingoes may suppress exotic mesopredators, particularly foxes. We outline further research required to determine if this suppression translates into a net benefit for threatened prey species.

scholarly journals Growth Responses of Wheat (Triticum aestivumL. var. HD 2329) Exposed to Ambient Air Pollution under Varying Fertility Regimes

2003 ◽  
Vol 3 ◽  
pp. 799-810 ◽  
Author(s):  
Anoop Singh ◽  
S. B. Agrawal ◽  
Dheeraj Rathore
Keyword(s):  
Air Pollution ◽  
Negative Impact ◽  
Growth Parameters ◽  
Urban Air Pollution ◽  
Ambient Air ◽  
Energy Utilization ◽  
Ambient Air Pollution ◽  
Growth And Yield ◽  
Motor Vehicles ◽  
Growth Responses

The problem of urban air pollution has attracted special attention in India due to a tremendous increase in the urban population; motor vehicles vis a vis the extent of energy utilization. Field studies were conducted on wheat crops (Triticum aestivum L. var. HD 2329) by keeping the pot-grown plants in similar edaphic conditions at nine different sites in Allahabad City to quantify the effects of ambient air pollution levels on selected growth and yield parameters. Air quality monitoring was done at all the sites for gaseous pollutants viz. SO2, NO2, and O3. Various growth parameters (plant height, biomass, leaf area, NPP, etc.) showed adverse effects at sites receiving higher pollution load. Reduction in test weight and harvest index was found to be directly correlated with the levels of pollutant concentrations. The study clearly showed the negative impact of air pollution on periurban agriculture.

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