Intraspecific predator inhibition, not a prey size refuge, enables oyster population persistence during predator outbreaks

2018 ◽  
Vol 602 ◽  
pp. 155-167 ◽  
Author(s):  
HS Booth ◽  
TJ Pusack ◽  
JW White ◽  
CD Stallings ◽  
DL Kimbro
Keyword(s):  
Prey Size ◽  
Population Persistence ◽  
Oyster Population ◽  
Size Refuge

scholarly journals Understanding drivers of wild oyster population persistence

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mickael Teixeira Alves ◽  
Nick G. H. Taylor ◽  
Hannah J. Tidbury
Keyword(s):  
Population Density ◽  
Carrying Capacity ◽  
Pacific Oyster ◽  
Wild Population ◽  
Population Persistence ◽  
Oyster Reefs ◽  
Oyster Population ◽  
Northern European ◽  
Age Structured ◽  
The Impact

AbstractPersistence of wild Pacific oyster, Magallana gigas, also known as Crassostrea gigas, has been increasingly reported across Northern European waters in recent years. While reproduction is inhibited by cold waters, recent warm summer temperature has increased the frequency of spawning events. Although correlation between the increasing abundance of Pacific oyster reefs in Northern European waters and climate change is documented, persistence of wild populations may also be influenced by external recruitment from farmed populations and other wild oyster populations, as well as on competition for resources with aquaculture sites. Our understanding of the combined impact of the spawning frequency, external recruitment, and competition on wild population persistence is limited. This study applied an age-structured model, based on ordinary differential equations, to describe an oyster population under discrete temperature-related dynamics. The impact of more frequent spawning events, external recruitment, and changes in carrying capacity on Pacific oyster density were simulated and compared under theoretical scenarios and two case studies in Southern England. Results indicate that long term persistence of wild oyster populations towards carrying capacity requires a high frequency of spawning events but that in the absence of spawning, external recruitment from farmed populations and other wild oyster populations may act to prevent extinction and increase population density. However, external recruitment sources may be in competition with the wild population so that external recruitment is associated with a reduction in wild population density. The implications of model results are discussed in the context of wild oyster population management.

scholarly journals Size-dependent locomotory performance creates a behaviorally mediated prey size refuge in the marine snail Olivella semistriata: a study in the natural habitat

2019 ◽  
Vol 66 (1) ◽  
pp. 57-62
Author(s):  
Callie A Veelenturf ◽  
Winfried S Peters
Keyword(s):  
Size Dependence ◽  
Prey Size ◽  
Natural Habitat ◽  
Individual Performance ◽  
Large Prey ◽  
Natural Habitats ◽  
Size Dependent ◽  
Locomotory Performance ◽  
Causal Sequence ◽  
Size Refuge

Abstract The effects of the variability of individual prey locomotory performance on the vulnerability to predation are poorly understood, partly because individual performance is difficult to determine in natural habitats. To gain insights into the role(s) of individual variation in predatory relationships, we study a convenient model system, the neotropical sandy beach gastropod Olivella semistriata and its main predator, the carnivorous snail Agaronia propatula. The largest size class of O. semistriata is known to be missing from A. propatula’s spectrum of subdued prey, although the predator regularly captures much larger individuals of other taxa. To resolve this conundrum, we analyzed predation attempts in the wild. While A. propatula attacked O. semistriata of all sizes, large prey specimens usually escaped by ‘sculling’, an accelerated, stepping mode of locomotion. Olivella semistriata performed sculling locomotion regardless of size, but sculling velocities determined in the natural environment increased strongly with size. Thus, growth in size as such does not establish a prey size refuge in which O. semistriata is safe from predation. Rather, a behaviorally mediated size refuge is created through the size-dependence of sculling performance. Taken together, this work presents a rare quantitative characterization in the natural habitat of the causal sequence from the size-dependence of individual performance, to the prey size-dependent outcome of predation attempts, to the size bias in the predator’s prey spectrum.

Population Persistence, Pollination Mutualisms, and Figs in Fragmented Tropical Landscapes

1998 ◽  
Vol 12 (6) ◽  
pp. 1416-1420 ◽  
Author(s):  
Nick A. Mawdsley ◽  
Stephen G. Compton ◽  
Robert J. Whittaker
Keyword(s):  
Population Persistence ◽  
Tropical Landscapes

scholarly journals Prey Size Decline as a Unifying Ecological Selecting Agent in Pleistocene Human Evolution

Quaternary ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 7
Author(s):  
Miki Ben-Dor ◽  
Ran Barkai
Keyword(s):  
Prey Size ◽  
Prey Availability ◽  
Stone Tool ◽  
Foraging Efficiency ◽  
Energetic Cost ◽  
Large Prey ◽  
Biomass Density ◽  
Cultural Changes ◽  
Progressive Decline ◽  
Brain Expansion

We hypothesize that megafauna extinctions throughout the Pleistocene, that led to a progressive decline in large prey availability, were a primary selecting agent in key evolutionary and cultural changes in human prehistory. The Pleistocene human past is characterized by a series of transformations that include the evolution of new physiological traits and the adoption, assimilation, and replacement of cultural and behavioral patterns. Some changes, such as brain expansion, use of fire, developments in stone-tool technologies, or the scale of resource intensification, were uncharacteristically progressive. We previously hypothesized that humans specialized in acquiring large prey because of their higher foraging efficiency, high biomass density, higher fat content, and the use of less complex tools for their acquisition. Here, we argue that the need to mitigate the additional energetic cost of acquiring progressively smaller prey may have been an ecological selecting agent in fundamental adaptive modes demonstrated in the Paleolithic archaeological record. We describe several potential associations between prey size decline and specific evolutionary and cultural changes that might have been driven by the need to adapt to increased energetic demands while hunting and processing smaller and smaller game.

Does prey abundance affect prey size selection by the Eagle Owl (Bubo bubo)?

2021 ◽  
Author(s):  
Jorge Tobajas ◽  
Carlos Rouco ◽  
Javier Fernandez-de-Simon ◽  
Francisco Díaz-Ruiz ◽  
Francisca Castro ◽  
...  
Keyword(s):  
Prey Size ◽  
Prey Abundance ◽  
Bubo Bubo ◽  
Size Selection ◽  
Eagle Owl

scholarly journals Terrestrial Morphotypes of Aquatic Plants Display Improved Seed Germination to Deal with Dry or Low-Rainfall Periods

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 741
Author(s):  
Rocío Fernández-Zamudio ◽  
Pablo García-Murillo ◽  
Carmen Díaz-Paniagua
Keyword(s):  
Seed Germination ◽  
Plant Species ◽  
Aquatic Plants ◽  
Aquatic Plant ◽  
Population Persistence ◽  
Temporary Ponds ◽  
Percent Germination ◽  
Plant Assemblages ◽  
Viable Seeds

In temporary ponds, seed germination largely determines how well aquatic plant assemblages recover after dry periods. Some aquatic plants have terrestrial morphotypes that can produce seeds even in dry years. Here, we performed an experiment to compare germination patterns for seeds produced by aquatic and terrestrial morphotypes of Ranunculus peltatus subsp. saniculifolius over the course of five inundation events. During the first inundation event, percent germination was higher for terrestrial morphotype seeds (36.1%) than for aquatic morphotype seeds (6.1%). Seed germination peaked for both groups during the second inundation event (terrestrial morphotype: 47%; aquatic morphotype: 34%). Even after all five events, some viable seeds had not yet germinated (terrestrial morphotype: 0.6%; aquatic morphotype: 5%). We also compared germination patterns for the two morphotypes in Callitriche brutia: the percent germination was higher for terrestrial morphotype seeds (79.5%) than for aquatic morphotype seeds (41.9%). Both aquatic plant species use two complementary strategies to ensure population persistence despite the unpredictable conditions of temporary ponds. First, plants can produce seeds with different dormancy periods that germinate during different inundation periods. Second, plants can produce terrestrial morphotypes, which generate more seeds during dry periods, allowing for re-establishment when conditions are once again favorable.

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