Allometry in the terminal velocity – dispersal architecture relationship explains variation in dispersal and offspring provisioning strategies in wind dispersed Asteraceae species

2017 ◽  
Vol 65 (2) ◽  
pp. 149 ◽  
Author(s):  
Samiya Tabassum ◽  
Stephen P. Bonser
Keyword(s):  
Volume Ratio ◽  
Terminal Velocity ◽  
Dispersal Ability ◽  
Allometric Relationships ◽  
Allometric Relationship ◽  
High Dispersal ◽  
Provisioning Strategies ◽  
Drop Time ◽  
Allocation Strategies ◽  
Do So

Competition can simultaneously favour high dispersal ability (to transport offspring to more favourable habitats) and large seed size (to maximise offspring provisioning). In wind dispersed Asteraceae species, seeds are enclosed within an achene with hair-like projections from the achene form a pappus that acts as a parachute to aid in dispersal. There is potentially an allometric relationship between terminal velocity and pappus to achene volume ratio (dispersal architecture), with changes in dispersal architecture resulting in disproportionately high or low impacts on terminal velocity. We tested the hypothesis that competition induces shifts in dispersal architecture depending on the allometric relationship between terminal velocity and dispersal architecture. We estimated dispersal architecture of diaspores from seven wind dispersed Asteraceae species from environments with low and high neighbour densities. We also estimated diaspore terminal velocity for a subset of these species by recording drop time in a 2 m tube. Diaspores of one species had dispersal architecture promoting higher dispersal under high neighbour density, diaspores of two species had dispersal architecture promoting lower dispersal under high neighbour density, and dispersal architecture was not significantly different between high and low density environments for four of the species. Species showed a common allometric relationship between terminal velocity and dispersal architecture. The allometric relationship predicts dispersal architecture changes across environments differing in neighbour density. Species with dispersal architecture promoting higher dispersal under high neighbour density do so where small increases in dispersal architecture yield large decreases in terminal velocity. Our research suggests that the nature of allometric relationships between traits can help to explain allocation strategies across environments.

scholarly journals Dispersal and Differentiation of Deep-Sea Mussels of the GenusBathymodiolus(Mytilidae, Bathymodiolinae)

2009 ◽  
Vol 2009 ◽  
pp. 1-15 ◽  
Author(s):  
Akiko Kyuno ◽  
Mifue Shintaku ◽  
Yuko Fujita ◽  
Hiroto Matsumoto ◽  
Motoo Utsumi ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Differentiation ◽  
Shallow Water ◽  
Deep Sea ◽  
Dispersal Ability ◽  
Evolutionary Transition ◽  
Significant Genetic Differentiation ◽  
Evolutionary Processes ◽  
High Dispersal ◽  
High Gene

We sequenced the mitochondrial ND4 gene to elucidate the evolutionary processes ofBathymodiolusmussels and mytilid relatives. Mussels of the subfamily Bathymodiolinae from vents and seeps belonged to 3 groups and mytilid relatives from sunken wood and whale carcasses assumed the outgroup positions to bathymodioline mussels. Shallow water mytilid mussels were positioned more distantly relative to the vent/seep mussels, indicating an evolutionary transition from shallow to deep sea via sunken wood and whale carcasses.Bathymodiolus platifronsis distributed in the seeps and vents, which are approximately 1500 km away. There was no significant genetic differentiation between the populations. There existed high gene flow betweenB. septemdierumandB. breviorand low but not negligible gene flow betweenB. marisindicusandB. septemdierumorB. brevior, although their habitats are 5000–10 000 km away. These indicate a high adaptability to the abyssal environments and a high dispersal ability ofBathymodiolusmussels.

Allometric relationships between embryonic heart rate and fresh egg mass in birds

2001 ◽  
Vol 204 (1) ◽  
pp. 165-174 ◽  
Author(s):  
H. Tazawa ◽  
J.T. Pearson ◽  
T. Komoro ◽  
A. Ar
Keyword(s):  
Heart Rate ◽  
Embryonic Heart ◽  
Egg Mass ◽  
Published Data ◽  
Tyto Alba ◽  
Allometric Relationships ◽  
Allometric Relationship ◽  
Subsequent Increase ◽  
Developmental Patterns ◽  
Precocial Birds

Previously, we have measured daily changes (developmental patterns) in embryonic heart rate (fh) in altricial and semi-altricial (ASA) birds (range of mean fresh egg mass approximately 1–20 g), semi-precocial seabirds (egg mass approximately 38–288 g) and precocial birds (egg mass approximately 6–1400 g). An allometric relationship between embryonic fh at 80 % of incubation duration (ID) and fresh egg mass (M) has been derived for six species of precocial bird (fh at 80 % ID=429M(−0.118)). In the present study, additional measurements of embryonic fh in three ASA species, the barn owl Tyto alba, the cattle egret Bubulcus ibis and the lanner falcon Falco biarmicus, were made to extend the egg mass range (20–41 g), and the allometric relationships of embryonic fh for these ASA birds and the precocial and semi-precocial (PSP) groups were investigated from published data. The developmental patterns of embryonic fh in three relatively large ASA species did not show a significant increase prior to the pipping period, unlike those in small ASA birds, but tended to be constant, with a subsequent increase during pipping. The allometric relationship derived for ASA birds was fh at 80 % ID=371M(−0.121) (r=−0.846, P<0.001, N=20) and that for PSP birds was fh at 80 % ID=433M(−0.121) (r=−0.963, P<0.001, N=13). The slopes were parallel, but fh of ASA embryos was low compared with that of PSP embryos with the same egg mass. In ASA birds, embyronic fh was maximal during the pipping (perinatal) period, and the maximum fh (fh(max)) was significantly related to fresh egg mass: fh(max)=440M(−0.127) (r=−0.840, P<0.001, N=20). The allometric relationships for fh at 80 % ID in PSP and fh(max) in ASA embryos were statistically identical. Accordingly, embryonic fh at 80 % ID in PSP birds and fh(max) during pipping in ASA birds can be expressed by a single allometric equation: fh=437M(−0.123) (r=−0.948, P<0.001, N=33).

scholarly journals High dispersal ability is related to fast life-history strategies

2018 ◽  
Vol 106 (4) ◽  
pp. 1349-1362 ◽  
Author(s):  
Noelle G. Beckman ◽  
James M. Bullock ◽  
Roberto Salguero-Gómez
Keyword(s):  
Life History ◽  
Life History Strategies ◽  
Dispersal Ability ◽  
High Dispersal

scholarly journals Serial founder effects and genetic differentiation during worldwide range expansion of monarch butterflies

2014 ◽  
Vol 281 (1797) ◽  
pp. 20142230 ◽  
Author(s):  
Amanda A. Pierce ◽  
Myron P. Zalucki ◽  
Marie Bangura ◽  
Milan Udawatta ◽  
Marcus R. Kronforst ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Differentiation ◽  
Genetic Drift ◽  
North American ◽  
Range Expansion ◽  
Dispersal Ability ◽  
Founder Effects ◽  
Long Distance ◽  
Mobile Species ◽  
High Dispersal

Range expansions can result in founder effects, increasing genetic differentiation between expanding populations and reducing genetic diversity along the expansion front. However, few studies have addressed these effects in long-distance migratory species, for which high dispersal ability might counter the effects of genetic drift. Monarchs ( Danaus plexippus ) are best known for undertaking a long-distance annual migration in North America, but have also dispersed around the world to form populations that do not migrate or travel only short distances. Here, we used microsatellite markers to assess genetic differentiation among 18 monarch populations and to determine worldwide colonization routes. Our results indicate that North American monarch populations connected by land show limited differentiation, probably because of the monarch's ability to migrate long distances. Conversely, we found high genetic differentiation between populations separated by large bodies of water. Moreover, we show evidence for serial founder effects across the Pacific, suggesting stepwise dispersal from a North American origin. These findings demonstrate that genetic drift played a major role in shaping allele frequencies and created genetic differentiation among newly formed populations. Thus, range expansion can give rise to genetic differentiation and declines in genetic diversity, even in highly mobile species.

The necessity for testing germination of fresh seeds in studies on diaspore heteromorphism as a life-history strategy

2013 ◽  
Vol 23 (2) ◽  
pp. 83-88 ◽  
Author(s):  
Jerry M. Baskin ◽  
Juan J. Lu ◽  
Carol C. Baskin ◽  
Dun Y. Tan
Keyword(s):  
Life History ◽  
High Risk ◽  
Life History Strategy ◽  
The Other ◽  
Dispersal Ability ◽  
Correct Interpretation ◽  
Bet Hedging ◽  
High Dispersal ◽  
Dimorphic Species ◽  
Dispersal Characteristics

AbstractMany studies have compared diaspore dispersal ability and degree of dormancy in the two diaspores of dimorphic plant species. A primary goal of these studies was to determine if germination and dispersal characteristics of the two morphs fit within a high risk–low risk (bet-hedging) life-history strategy, i.e. high dispersal/low dormancy in one morph versus low dispersal/high dormancy in the other one. In a survey of 26 papers on 28 diaspore dimorphic species, we found that in 12 of the studies, which were published between 1978 and 2008, seeds were stored, and thus possibly afterripened, before they were tested for germination. The 14 papers that tested fresh seeds were published between 1963 and 2010. Failure to test fresh seeds likely resulted in misinterpretation of the diaspore dispersal/dormancy strategy in some of the species investigated. We conclude that it is imperative that fresh seeds be tested for germination in order to be certain that the correct relationship between dispersal and dormancy is elucidated, and thus that the correct interpretation is made concerning life-history strategy and bet-hedging, in dimorphic species.

scholarly journals High dispersal ability inhibits speciation in a continental radiation of passerine birds

2011 ◽  
Vol 279 (1733) ◽  
pp. 1567-1574 ◽  
Author(s):  
Santiago Claramunt ◽  
Elizabeth P. Derryberry ◽  
J. V. Remsen ◽  
Robb T. Brumfield
Keyword(s):  
Dispersal Ability ◽  
South American ◽  
Flight Performance ◽  
Negative Effects ◽  
Dispersal Model ◽  
High Dispersal ◽  
Speciation Rates ◽  
Geographical Expansion ◽  
The Relationship ◽  
Degree Of Fragmentation

Dispersal can stimulate speciation by facilitating geographical expansion across barriers or inhibit speciation by maintaining gene flow among populations. Therefore, the relationship between dispersal ability and speciation rates can be positive or negative. Furthermore, an ‘intermediate dispersal’ model that combines positive and negative effects predicts a unimodal relationship between dispersal and diversification. Because both dispersal ability and speciation rates are difficult to quantify, empirical evidence for the relationship between dispersal and diversification remains scarce. Using a surrogate for flight performance and a species-level DNA-based phylogeny of a large South American bird radiation (the Furnariidae), we found that lineages with higher dispersal ability experienced lower speciation rates. We propose that the degree of fragmentation or permeability of the geographical setting together with the intermediate dispersal model are crucial in reconciling previous, often contradictory findings regarding the relationship between dispersal and diversification.

Achieving Conservation Biology Objectives with Fire in the Pacific Northwest

1996 ◽  
Vol 10 (2) ◽  
pp. 417-421 ◽  
Author(s):  
James K. Agee
Keyword(s):  
Pacific Northwest ◽  
Conservation Biology ◽  
Ponderosa Pine ◽  
Fire Regime ◽  
Fire Frequency ◽  
Dispersal Ability ◽  
Natural Ecosystems ◽  
High Dispersal ◽  
The Pacific ◽  
Ecosystem Level

Fire has been a part of natural ecosystems for many millennia. The species of those ecosystems have evolved through a series of “coarse filters,” one of which is resistance or resilience to disturbance by fire. Plant adaptations to fire include the ability to sprout, seed bank adaptations in the soil or canopy, high dispersal ability for seeds, and thick bark. These adaptations are often to a particular fire regime, or combination of fire frequency, intensity, extent, and season. Fire can be used by managers to achieve species to ecosystem-level conservation biology objectives. Examples using prescribed fire include the grasslands of the Puget Trough of Washington State, maintenance of oak woodlands, and perpetuation of ponderosa pine/mixed-conifer forests.

scholarly journals Dispersal limitations of early life stages and sibling aggregations in a broadcastingMilleporahydrocoral, as revealed by parentage analysis

2018 ◽  
Author(s):  
Caroline E. Dubé ◽  
Emilie Boissin ◽  
Alexandre Mercière ◽  
Serge Planes
Keyword(s):  
Geographic Distance ◽  
French Polynesia ◽  
Parentage Analysis ◽  
Dispersal Ability ◽  
Dispersal Patterns ◽  
High Dispersal ◽  
Local Sustainability ◽  
Limited Dispersal ◽  
Dispersal Events ◽  
Critical Process

AbstractDispersal is a critical process for the persistence and productivity of marine populations. For many reef species, there is increasing evidence that local demography and self-recruitment have major consequences on their genetic diversity and adaptation to environmental change. Yet empirical data of dispersal patterns in reef-building species remain scarce. Here, we document the first genetic estimates of local dispersal and self-recruitment in a broadcasting reef-builder, the hydrocoralMillepora platyphylla. Using microsatellite markers, we gathered genotypic information from 3160 georeferenced colonies collected over 9000 m2of reef in three adjacent habitats in Moorea, French Polynesia; the mid slope, upper slope and back reef. Our parentage analysis revealed a predominance of self-recruitment with 58% of sexual propagules produced locally. Sexual propagules often settled at less than 10 meters from their parents and dispersal events decrease with increasing geographic distance. Limited dispersal among adjacent habitats via cross-reef transport was also detected. Sibship analysis showed that both full and half siblings recruit together on the reef, resulting in sibling aggregations. The identification of local families revealed discrepancies between dispersal patterns of sexual and asexual propagules. Self-recruits are dispersed with along-reef currents and settled in alignment with the location of their parents, while the dispersal of asexual fragments is heavily influenced by wave-driven cross-reef currents. Our findings highlight the importance of self-recruitment together with clonality in stabilising population dynamics, as it can enhance local sustainability and resilience to disturbance, but also raise uncertainties on the widely accepted high dispersal ability of broadcasting reef species.

scholarly journals Ecological Correlates of Elevational Range Shifts in Tropical Birds

2021 ◽  
Vol 9 ◽  
Author(s):  
Montague H. C. Neate-Clegg ◽  
Samuel E. I. Jones ◽  
Joseph A. Tobias ◽  
William D. Newmark ◽  
Çaǧan H. Şekercioǧlu
Keyword(s):  
Climate Change ◽  
Bird Species ◽  
Species Traits ◽  
Rate Of Change ◽  
Range Shifts ◽  
Dispersal Ability ◽  
High Dispersal ◽  
Elevational Shift ◽  
Elevational Range ◽  
The Tropics

Globally, birds have been shown to respond to climate change by shifting their elevational distributions. This phenomenon is especially prevalent in the tropics, where elevational gradients are often hotspots of diversity and endemism. Empirical evidence has suggested that elevational range shifts are far from uniform across species, varying greatly in the direction (upslope vs. downslope) and rate of change (speed of elevational shift). However, little is known about the drivers of these variable responses to climate change, limiting our ability to accurately project changes in the future. Here, we compile empirical estimates of elevational shift rates (m/yr) for 421 bird species from eight study sites across the tropics. On average, species shifted their mean elevations upslope by 1.63 ± 0.30 m/yr, their upper limits by 1.62 m ± 0.38 m/yr, and their lower limits by 2.81 ± 0.42 m/yr. Upslope shift rates increased in smaller-bodied, less territorial species, whereas larger species were more likely to shift downslope. When considering absolute shift rates, rates were fastest for species with high dispersal ability, low foraging strata, and wide elevational ranges. Our results indicate that elevational shift rates are associated with species’ traits, particularly body size, dispersal ability, and territoriality. However, these effects vary substantially across sites, suggesting that responses of tropical montane bird communities to climate change are complex and best predicted within the local or regional context.

scholarly journals Reinforcement Learning Applied to a Cryptocurrency Portfolio in a Complexity Environment

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Daniel Sousa Barra ◽  
Helberte França Almeida ◽  
Rafael Jasper Feltrin ◽  
Solange Regina Marin
Keyword(s):  
Machine Learning ◽  
Reinforcement Learning ◽  
Optimization Algorithm ◽  
Financial Assets ◽  
Allocation Strategies ◽  
Do So ◽  
The Ideal

Recently, cryptocurrencies have been used as financial assets and have presented positive returns, albeit their volatility is high. This paper aims to elaborate a hypothetical cryptocurrency portfolio and to do so, employs machine learning and an optimization algorithm to define the ideal amount to be allocated in each asset. The results show the hypothetical portfolio presents superior returns and lesser volatility compared to other allocation strategies.

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