Two Processes Regulating Trophic Energy Flow in Pelagic and Terrestrial Ecosystems: Trophic Efficiency and Body Size–Dependent Biomass Production: (A Reply to Giacomini)

2018 ◽  
Vol 191 (3) ◽  
pp. 364-367
Author(s):  
Richard McGarvey ◽  
Natalie Dowling ◽  
Joel E. Cohen
Keyword(s):  
Body Size ◽  
Biomass Production ◽  
Energy Flow ◽  
Terrestrial Ecosystems ◽  
Size Dependent

Body size-dependent Cd accumulation in the zebra mussel Dreissena polymorpha from different routes

Chemosphere ◽  
2017 ◽  
Vol 168 ◽  
pp. 825-831 ◽  
Author(s):  
Wen-Li Tang ◽  
Douglas Evans ◽  
Lisa Kraemer ◽  
Huan Zhong
Keyword(s):  
Body Size ◽  
Zebra Mussel ◽  
Dreissena Polymorpha ◽  
Cd Accumulation ◽  
Size Dependent

An ecological explanation for hyperallometric scaling of reproduction

2021 ◽  
Author(s):  
Tomos Potter ◽  
Anja Felmy
Keyword(s):  
Body Size ◽  
Reproductive Output ◽  
Resource Competition ◽  
Natural Populations ◽  
Scaling Exponent ◽  
Wild Populations ◽  
Wet Season ◽  
Size Dependent ◽  
In The Wild ◽  
The Relationship

AbstractIn wild populations, large individuals have disproportionately higher reproductive output than smaller individuals. We suggest an ecological explanation for this observation: asymmetry within populations in rates of resource assimilation, where greater assimilation causes both increased reproduction and body size. We assessed how the relationship between size and reproduction differs between wild and lab-reared Trinidadian guppies. We show that (i) reproduction increased disproportionately with body size in the wild but not in the lab, where effects of resource competition were eliminated; (ii) in the wild, the scaling exponent was greatest during the wet season, when resource competition is strongest; and (iii) detection of hyperallometric scaling of reproduction is inevitable if individual differences in assimilation are ignored. We propose that variation among individuals in assimilation – caused by size-dependent resource competition, niche expansion, and chance – can explain patterns of hyperallometric scaling of reproduction in natural populations.

scholarly journals On the potential vegetation feedbacks that enhance phosphorus availability – insights from a process-based model linking geological and ecological timescales

2014 ◽  
Vol 11 (13) ◽  
pp. 3661-3683 ◽  
Author(s):  
C. Buendía ◽  
S. Arens ◽  
T. Hickler ◽  
S. I. Higgins ◽  
P. Porada ◽  
...  
Keyword(s):  
Biomass Production ◽  
Primary Productivity ◽  
Chemical Weathering ◽  
Production Efficiency ◽  
Root Exudation ◽  
Terrestrial Ecosystems ◽  
Global Scale ◽  
P Uptake ◽  
P Availability ◽  
P Limitation

Abstract. In old and heavily weathered soils, the availability of P might be so small that the primary production of plants is limited. However, plants have evolved several mechanisms to actively take up P from the soil or mine it to overcome this limitation. These mechanisms involve the active uptake of P mediated by mycorrhiza, biotic de-occlusion through root clusters, and the biotic enhancement of weathering through root exudation. The objective of this paper is to investigate how and where these processes contribute to alleviate P limitation on primary productivity. To do so, we propose a process-based model accounting for the major processes of the carbon, water, and P cycles including chemical weathering at the global scale. Implementing P limitation on biomass synthesis allows the assessment of the efficiencies of biomass production across different ecosystems. We use simulation experiments to assess the relative importance of the different uptake mechanisms to alleviate P limitation on biomass production. We find that active P uptake is an essential mechanism for sustaining P availability on long timescales, whereas biotic de-occlusion might serve as a buffer on timescales shorter than 10 000 yr. Although active P uptake is essential for reducing P losses by leaching, humid lowland soils reach P limitation after around 100 000 yr of soil evolution. Given the generalized modelling framework, our model results compare reasonably with observed or independently estimated patterns and ranges of P concentrations in soils and vegetation. Furthermore, our simulations suggest that P limitation might be an important driver of biomass production efficiency (the fraction of the gross primary productivity used for biomass growth), and that vegetation on old soils has a smaller biomass production rate when P becomes limiting. With this study, we provide a theoretical basis for investigating the responses of terrestrial ecosystems to P availability linking geological and ecological timescales under different environmental settings.

Size-dependent seasonal activity for males of the dung beetle Copris acutidens (Coleoptera: Scarabaeidae)

2019 ◽  
Vol 151 (6) ◽  
pp. 757-767 ◽  
Author(s):  
Mayumi Akamine
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Dung Beetle ◽  
Threshold Value ◽  
Reproductive Period ◽  
Seasonal Activity ◽  
Size Dependent ◽  
Horn Length ◽  
Female Bias ◽  
Early Activity

AbstractThis study aimed to determine differences in activities between two male morphs of the dung beetle Copris acutidens Motschulsky (Coleoptera: Scarabaeidae) during the reproductive period and to examine the size distribution of reproductive males that stayed in nests. The activities of two male morphs distinguished by a threshold value of body size were compared with those by horn length. Regardless of body size or horn length, earlier activity of minor males was observed during the reproductive period. The sex ratio showed the greatest female bias when minor males were the more abundant than major males, indicating that minor males were the most active when competition was the weakest and these could avoid direct combat with major males. In morphs distinguished by horn length, more major males than minor males stayed in nests with females although the major males became the most active from the middle of the reproductive period. Thus, longer horns may directly confer a competitive advantage to males, enabling them to stay in nests with females, whereas early activity of minor males does not always indicate the effect of horn length directly. Therefore, this behaviour may occur regardless of whether the morphs differ in body size or horn length.

scholarly journals Perch Selection by Three Cooccurring Species ofCelithemis(Odonata: Libellulidae): Testing for a Competitive Hierarchy among Similar Species

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Wade B. Worthen ◽  
Parker H. Morrow
Keyword(s):  
Body Size ◽  
Niche Partitioning ◽  
Open Water ◽  
The Other ◽  
Similar Species ◽  
Male Body ◽  
Size Dependent ◽  
Anatomical Characters ◽  
Relative Abundances ◽  
Imagej Software

In many communities of perching dragonflies (Odonata: Libellulidae), a size-dependent competitive hierarchy creates a positive relationship between male body size and perch height. We tested for this pattern among three similar-sized species:Celithemis elisa,C. fasciata, andC. ornata.Males were caught and photographed from May to July 2015 at Ashmore Heritage Preserve, Greenville County, SC, USA, and perch heights and perch distance to open water were measured. Five indices of body size were measured with ImageJ software: abdomen length, forewing length, hindwing length, area of forewing, and area of hindwing.Celithemis fasciatawas significantly larger than the other two species for all five anatomical characters and used perches that were significantly taller and closer to open water than the other species, though these differences changed over the summer. Aggressive interactions between and within species were tallied and compared to expected distributions based on mean relative abundances derived from hourly abundance counts. Patterns of interspecific aggression were also consistent with a size-dependent hierarchy: the largeC. fasciatawas attacked less frequently, and the smallC. ornatamore frequently, than predicted by their relative abundances. We conclude that even small differences in body size may contribute to niche partitioning in perch selection.

Body-size-dependent Iodine-131 S values

2020 ◽  
Vol 40 (4) ◽  
pp. 1311-1320
Author(s):  
Yeon Soo Yeom ◽  
Keith Griffin ◽  
Bangho Shin ◽  
Chansoo Choi ◽  
Haegin Han ◽  
...  
Keyword(s):  
Body Size ◽  
Size Dependent ◽  
Iodine 131

scholarly journals Factors driving semi-aquatic predator occurrence in traditional cattle drinking pools: conservation issues

2016 ◽  
Author(s):  
Raoul Manenti ◽  
Nicola Zanetti ◽  
Roberta Pennati ◽  
Giorgio Scarì
Keyword(s):  
Energy Flow ◽  
Hot Spot ◽  
Terrestrial Ecosystems ◽  
Water Bodies ◽  
Small Water ◽  
Invertebrate Prey ◽  
Aquatic Predators ◽  
Lotic Environments ◽  
Predator Community ◽  
Small Water Bodies

<p>In several cases, human impact on water bodies and on their freshwater communities is detrimental, but in some cases the human activity may favour and enhance the biodiversity of small water bodies, as traditional cattle drinking pools. Despite their small size, small water bodies may constitute hot spot of biodiversity often representing the only lentic aquatic biotope in landscapes where superficial water lacks or flows in lotic environments like creeks and streams. Predators are good indicators of biodiversity in ponds and give information of food chain web complexity. In particular, semi-aquatic predators like amphibians and dragonflies may account for a substantial percentage of energy flow between aquatic and terrestrial ecosystems. In this study, we evaluated the conservation value of traditional cattle drinking pools building by assessing the factors determining the occurrence and distribution of the semi-aquatic predators. From April to August 2015, we investigated 30 distinct pools recording several abiotic and biotic environmental variables. We detected 4 semi-aquatic predators: <em>Salamandra salamandra</em> larvae, <em>Triturus carnifex</em>, <em>Aeshna</em> sp. larvae and <em>Libellula</em> sp. larvae. Abiotic features played a major role in shaping the predator community that resulted linked to stable, with no dryness period, and large drinking pools. Invertebrate prey biomass was not particularly important, while vegetation cover and occurrence of unpalatable tadpoles were the most important biotic features of the pools. Our study provides novel evidence on the importance of cattle drinking pools management to preserve biodiversity especially in areas where traditional pastoral activity is disappearing.</p>

A Novel Approach to Scaling Age-, Sex-, and Body Size-Dependent Thoracic Responses using Structural Properties of Human Ribs

2020 ◽  
Author(s):  
Yun-Seok Kang ◽  
John H. Bolte IV ◽  
Jason Stammen ◽  
Kevin Moorhouse ◽  
Amanda M. Agnew
Keyword(s):  
Body Size ◽  
Structural Properties ◽  
Size Dependent ◽  
Novel Approach

scholarly journals The Early Cretaceous terrestrial ecosystems of the Jehol Biota based on food-web and energy-flow models

2014 ◽  
Vol 113 (3) ◽  
pp. 836-853 ◽  
Author(s):  
Masaki Matsukawa ◽  
Kenichiro Shibata ◽  
Kenta Sato ◽  
Xu Xing ◽  
Martin G. Lockley
Keyword(s):  
Food Web ◽  
Early Cretaceous ◽  
Energy Flow ◽  
Terrestrial Ecosystems ◽  
Jehol Biota ◽  
Flow Models
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