scholarly journals Dynamical analysis of the global elevational diversity gradient in passerine birds reveals a prominent role for highlands as species pumps

2020 ◽  
Author(s):  
Paul van Els ◽  
Leonel Herrera-Alsina ◽  
Alex L. Pigot ◽  
Rampal Etienne
Keyword(s):  
Evolutionary Dynamics ◽  
Strong Support ◽  
High Elevation ◽  
Dynamical Analysis ◽  
Reverse Direction ◽  
Passerine Birds ◽  
Diversification Rates ◽  
Diversity Gradient ◽  
As Species ◽  
Almost All

Abstract Low elevation regions harbor the majority of the world’s species diversity compared to high elevation areas. This global elevational diversity gradient, suggests that lowland species have had more time to diversify, or that net diversification rates have been higher in the lowlands (either due to higher ecological limits or intrinsically higher diversification rates). However, highlands seem to be cradles of diversity as they contain many young endemics, suggesting that their rates of speciation are exceptionally fast. Here, we use a phylogenetic diversification model that accounts for the dispersal of species between different elevations to examine the evolutionary dynamics of the elevational diversity gradient in passerine birds, a group that has radiated globally to occupy almost all elevations and latitudes. We find strong support for a model where passerines diversify at the same rate in the highlands and the lowlands but where the rate of dispersal from high to low elevations is more than twice as fast as in the reverse direction. This suggests that while there is no consistent trend in diversification across elevations, highland regions act as species pumps because the diversity they generate migrates into the lowlands, thus setting up the observed gradient in passerine diversity. This species pump is particularly strong in the tropics, where the inferred rate of speciation is 1.4 times faster than in the temperate zone. We conclude that despite their lower diversity, highland regions are disproportionally important for maintaining diversity in the adjacent lowlands. The extinction of species in the tropical highlands due to rapid climate change this century could thus have major and long-lasting impacts on global passerine diversity.

scholarly journals Evolutionary dynamics of the elevational diversity gradient in passerine birds

2021 ◽  
Author(s):  
Paul van Els ◽  
Leonel Herrera-Alsina ◽  
Alex L. Pigot ◽  
Rampal S. Etienne
Keyword(s):  
Evolutionary Dynamics ◽  
Passerine Birds ◽  
Diversity Gradient

scholarly journals Pathogenic Variability of Pyricularia grisea from the High- and Mid-Elevation Zones of Bhutan

2000 ◽  
Vol 90 (6) ◽  
pp. 621-628 ◽  
Author(s):  
Thinlay ◽  
R. S. Zeigler ◽  
M. R. Finckh
Keyword(s):  
Rice Cultivar ◽  
High Elevation ◽  
Individual Plant ◽  
Growing Seasons ◽  
Reaction Index ◽  
Agroecological Zones ◽  
Pathogenic Variability ◽  
Almost All ◽  
High Elevations ◽  
Virulence Spectrum

Thirty isolates of P. griseacollected from rice during a blast epidemic in 1995 in the high (1,800 to 2,600 m) and middle (1,200 to 1,800 m) elevations of Bhutan and 80 isolates collected from one rice cultivar from two high- and two mid-elevation sites in 1996 were analyzed for virulence. Differential varieties were indica CO39, with five near-isogenic lines (NILs) for resistance genes in the genetic background of CO39, and japonica Lijiangxintuanheigu (LTH), with five NILs for LTH. Twelve selected Bhutanese landraces also were studied. In addition, 10 blast nurseries consisting of the NIL sets, important local landraces, and representatives of international differential groups were established in the 1996 and 1997 growing seasons in the mid- and high-elevation agroecological zones. The 110 isolates were differentiated into 53 pathotypes based on the 2 NIL sets. Thirteen isolates were avirulent on all of the NILs but were compatible with some landraces. Several isolates were able to attack one of the NILs of CO39 but not CO39. These results strongly suggest that both CO39 and LTH possess previously unidentified resistance. The landraces were not uniform in their reactions to the isolates. When a reaction index taking into account all individual plant reactions was used, isolates that had been assigned to the same pathotype could be further differentiated, indicating that the NIL sets could not completely discriminate virulences in Bhutanese P. grisea populations. In the trap nurseries, disease was always present in the middle elevations, but disease was very low during July 1996 in the high elevations and only present during August and September 1997. Almost all varietal groups were more frequently attacked in the middle than in the high elevations, indicating that the virulence spectrum is wider and the conduciveness of the environment is greater in the middle elevations. Landraces from the high elevations were most susceptible, followed by international differential groups 7 and 8. The results suggest that selection has yielded landraces with more complete and complex resistance in the more disease-conducive mid-elevation environment. At the same time, the pathogen population also possesses a wider virulence spectrum in that environment.

scholarly journals HSE Management System for Hotwork Operation at High Elevation in Shipbuilding Project

2018 ◽  
Vol 203 ◽  
pp. 02005 ◽  
Author(s):  
Idris Othman ◽  
Mohd Fauzan Helmy Ibrahim ◽  
Nasir Shafiq ◽  
Hisham Mohamad ◽  
Md Salim Kamil
Keyword(s):  
Management System ◽  
Safety Management ◽  
High Elevation ◽  
Peninsular Malaysia ◽  
Survey Method ◽  
Liquefied Petroleum Gas ◽  
The People ◽  
Fall From Height ◽  
Class C ◽  
Almost All

Shipyard industry is one of the growing industry in Malaysia. There is still a lot of room for improvement with regards to the safety aspects within the industry. This study presents the finding of a survey on the safety management in shipyard operation of class C and D in Peninsular Malaysia registered with Ministry of Finance Malaysia. Shipyard operation is considered a hazardous job. Most of the cases were due to fall from height, fire and explosion. Similar accidents happened in South Korea, where 8 fatalities and 31 injuries were reported in January to August 2017. The accidents were due to crane collapsed and explosion during welding works inside a hull of a Liquefied Petroleum Gas (LPG) carrier. This paper aims to study the Health, Safety and Environment Management System (HSEMS) of shipyard operations in Malaysia particularly in Class C and Class D shipyard. This study was conducted using a survey method following the Glenn D’s equation. The survey was targeted at the people who are involved in the industry including the staffs of clients, consultants and contractors. The findings of this study show that almost all the shipyards of Class C and D have HSEMS in placed but some are incomplete. Accidents still happen in the Malaysian shipyard industry from time to time. The gaps in the HSEMS that lead to the accident are highlighted in this paper. Nearly 10% of Class C and D shipyards do not have clear HSE Policy and this one of possible causes of accidents due to low priority given to HSE matters in this particular Class C and D shipyard.

scholarly journals Explaining the ocean's richest biodiversity hotspot and global patterns of fish diversity

2018 ◽  
Vol 285 (1888) ◽  
pp. 20181314 ◽  
Author(s):  
Elizabeth Christina Miller ◽  
Kenji T. Hayashi ◽  
Dongyuan Song ◽  
John J. Wiens
Keyword(s):  
Large Scale ◽  
Fish Diversity ◽  
Relative Importance ◽  
Diversification Rates ◽  
Marine Habitats ◽  
History Of ◽  
Richness Patterns ◽  
Colonization Time ◽  
Almost All

For most marine organisms, species richness peaks in the Central Indo-Pacific region and declines longitudinally, a striking pattern that remains poorly understood. Here, we used phylogenetic approaches to address the causes of richness patterns among global marine regions, comparing the relative importance of colonization time, number of colonization events, and diversification rates (speciation minus extinction). We estimated regional richness using distributional data for almost all percomorph fishes (17 435 species total, including approximately 72% of all marine fishes and approximately 33% of all freshwater fishes). The high diversity of the Central Indo-Pacific was explained by its colonization by many lineages 5.3–34 million years ago. These relatively old colonizations allowed more time for richness to build up through in situ diversification compared to other warm-marine regions. Surprisingly, diversification rates were decoupled from marine richness patterns, with clades in low-richness cold-marine habitats having the highest rates. Unlike marine richness, freshwater diversity was largely derived from a few ancient colonizations, coupled with high diversification rates. Our results are congruent with the geological history of the marine tropics, and thus may apply to many other organisms. Beyond marine biogeography, we add to the growing number of cases where colonization and time-for-speciation explain large-scale richness patterns instead of diversification rates.

scholarly journals Pleistocene megafaunal interaction networks became more vulnerable after human arrival

2015 ◽  
Vol 282 (1814) ◽  
pp. 20151367 ◽  
Author(s):  
Mathias M. Pires ◽  
Paul L. Koch ◽  
Richard A. Fariña ◽  
Marcus A. M. de Aguiar ◽  
Sérgio F. dos Reis ◽  
...  
Keyword(s):  
Structural Changes ◽  
Ecological Communities ◽  
Ecological Interactions ◽  
Ecological Data ◽  
The Past ◽  
As Species ◽  
Extinction Events ◽  
Almost All ◽  
The Impact ◽  
Unstable Dynamics

The end of the Pleistocene was marked by the extinction of almost all large land mammals worldwide except in Africa. Although the debate on Pleistocene extinctions has focused on the roles of climate change and humans, the impact of perturbations depends on properties of ecological communities, such as species composition and the organization of ecological interactions. Here, we combined palaeoecological and ecological data, food-web models and community stability analysis to investigate if differences between Pleistocene and modern mammalian assemblages help us understand why the megafauna died out in the Americas while persisting in Africa. We show Pleistocene and modern assemblages share similar network topology, but differences in richness and body size distributions made Pleistocene communities significantly more vulnerable to the effects of human arrival. The structural changes promoted by humans in Pleistocene networks would have increased the likelihood of unstable dynamics, which may favour extinction cascades in communities facing extrinsic perturbations. Our findings suggest that the basic aspects of the organization of ecological communities may have played an important role in major extinction events in the past. Knowledge of community-level properties and their consequences to dynamics may be critical to understand past and future extinctions.

scholarly journals From plant populations to communities: using hierarchical trait environment relationships to reveal within ecosystem filtering

2019 ◽  
Author(s):  
Lucas Deschamps ◽  
Raphaël Proulx ◽  
Nicolas Gross ◽  
Guillaume Rheault ◽  
Vincent Maire
Keyword(s):  
Evolutionary Dynamics ◽  
Functional Trait ◽  
Population Characteristics ◽  
Diversity Gradient ◽  
Species Specific ◽  
Turn Over ◽  
Favorable Conditions ◽  
Nutrient Conservation ◽  
Space Occupation ◽  
Demographic Responses

AbstractExplaining the existence of highly diverse plant communities under strong abiotic filtering is a long-standing challenge in ecology. Hierarchical aspects of abiotic and biotic filters are rarely taken into account and studies focus mainly on community-level aggregated patterns. Because variations in biotic conditions might take place in short abiotic gradient and within the tolerance of species in regional pool, it is likely that biotic filtering will select individuals within species and adjust population characteristics. To challenge this idea, we replicated a diversity gradient in four highly contrasted wetlands with an almost complete species turn-over, sampling individuals in communities irrespective of their taxonomic identities or status. Using hierarchical distributional modelling, we analyzed the variation of the mean and dispersion of functional trait space at the ecosystem, community and species level. We found that the abiotic differences between ecosystems filtered species contrasted in their growth/nutrient conservation trade-off, while within ecosystems community variation were mainly due to the partitioning of canopy and leaf adaptations to light conditions. We found strong species-specific functional and demographic responses of dominant species along the diversity gradient, especially for traits linked to biomass and space occupation. Two contrasted strategies emerged, with species using plasticity to maintain equally dense populations, while others used plasticity to become overwhelmingly abundant when in favorable conditions. Our results demonstrate that within ecosystems, variation in biotic conditions selects individuals within populations, revealing the importance of phenotypic variation for a species to be maintained in more or less diverse communities. Because phenotypic variations are related to demographic responses, it offers a way to link the study of species diversity and eco-evolutionary dynamics.

scholarly journals Eco-evolutionary feedbacks and the maintenance of metacommunity diversity in a changing environment

2020 ◽  
Author(s):  
Aidan P. Fielding ◽  
Jelena H. Pantel
Keyword(s):  
Environmental Change ◽  
Feedback Loop ◽  
Competitive Ability ◽  
Evolutionary Dynamics ◽  
Resource Competition ◽  
Landscape Scale ◽  
Phenotypic Evolution ◽  
Species Sorting ◽  
As Species ◽  
Multiple Species

AbstractThe presence and strength of resource competition can influence how organisms adaptively respond to environmental change. Selection may thus reflect a balance between two forces, adaptation to an environmental optimum and evolution to avoid strong competition. While this phenomenon has previously been explored for single communities, its implications for eco-evolutionary dynamics at the metacommunity scale are unknown. We developed a simulation model for the evolution of a quantitative trait that influences both an organism’s carrying capacity and its intra- and interspecific competitive ability. In the model, multiple species inhabit a variable three-patch landscape, and we varied the connectivity level of the species among patches, the presence and pace of directional environmental change, and the strength of competition between the species. Our results reflect some patterns previously observed in evolving metacommunity models, such as species sorting and community monopolization. However species sorting was more likely to occur in evolving communities without dispersal, and monopolization was observed only when environmental change was very rapid. We also detected an eco-evolutionary feedback loop between local phenotypic evolution at one site and competition at another site, which maintains species diversity in some conditions. The existence of a feedback loop maintained by dispersal indicates that eco-evolutionary dynamics in communities operate at a landscape scale.

scholarly journals HSE MANAGEMENT SYSTEM AT HIGH ELEVATION IN SHIPBUILDING PROJECT

2020 ◽  
Vol 5 (11) ◽  
pp. 117-127
Author(s):  
Idris Othman ◽  
Hisham Mohamad ◽  
Nasiman Sapari ◽  
Nasir Shafiq ◽  
Fauzan Ibrahim ◽  
...  
Keyword(s):  
Management System ◽  
Safety Management ◽  
High Elevation ◽  
Peninsular Malaysia ◽  
Survey Method ◽  
Liquefied Petroleum Gas ◽  
Class D ◽  
Fall From Height ◽  
Class C ◽  
Almost All

The Shipyard industry is one of the growing industry in Malaysia. There is still a lot of room for improvement with regards to the safety aspects within the industry. This study presents the finding of a survey on the safety management in shipyard operation of class C and D in Peninsular Malaysia as registered with Ministry of Finance Malaysia. Shipyard operation is considered a hazardous job. Most of the cases were due to fall from height, fire and explosion. The accidents were due to crane collapsed and explosion during welding works inside a hull of a Liquefied Petroleum Gas (LPG) carrier. The research aims to study the Health, Safety and Environment Management System (HSEMS) of shipyard operations in Malaysia particularly in Class C and Class D. This study was conducted using a survey method following the Glenn D’s equation. The findings of this study shown that almost all the shipyards had HSEMS in placed but some were incomplete. Accidents still happen in the Malaysian shipyard industry from time to time. Nearly 10% of shipyards did not have clear HSE Policy due to low priority given to HSE matters.

scholarly journals Macroevolutionary pattern of Saussurea (Asteraceae) provides insights into the drivers of radiating diversification

2021 ◽  
Vol 288 (1962) ◽  
Author(s):  
Xu Zhang ◽  
Jacob B. Landis ◽  
Yanxia Sun ◽  
Huajie Zhang ◽  
Nan Lin ◽  
...  
Keyword(s):  
Ecological Niche ◽  
Evolutionary Dynamics ◽  
Niche Breadth ◽  
Morphological Evolution ◽  
Distribution Data ◽  
Ecological Distribution ◽  
Rapid Radiation ◽  
Diversification Rates ◽  
Intrinsic Factors ◽  
Evolutionary Radiations

Evolutionary radiations have intrigued biologists for more than a century, yet our understanding of the drivers of radiating diversification is still limited. We investigate the roles of environmental and species-intrinsic factors in driving the rapid radiation of Saussurea (Asteraceae) by deploying a number of palaeoenvironment-, diversity- and trait-dependent models, as well as ecological distribution data. We show that three main clades of Saussurea began to diversify in the Miocene almost simultaneously, with increasing diversification rates (DRs) negatively dependent on palaeotemperature but not dependent on species diversity. Our trait-dependent models detect some adaptive morphological innovations associated with DR shifts, while indicating additional unobserved traits are also likely driving diversification. Accounting for ecological niche data, we further reveal that accelerations in DRs are correlated with niche breadth and the size of species' range. Our results point out a macroevolutionary scenario where both adaptive morphological evolution and ecological opportunities provided by palaeoenvironmental fluctuations triggered an exceptionally radiating diversification. Our study highlights the importance of integrating phylogenomic, morphological, ecological and model-based approaches to illustrate evolutionary dynamics of lineages in biodiversity hotspots.

scholarly journals Tarantula phylogenomics: A robust phylogeny of multiple tarantula lineages inferred from transcriptome data sheds light on the prickly issue of urticating setae evolution

2018 ◽  
Author(s):  
Stephen Foley ◽  
Tim Lueddecke ◽  
Dong-Qiang Chen ◽  
Henrik Krehenwinkel ◽  
Sven Kuenzel ◽  
...  
Keyword(s):  
New World ◽  
Strong Support ◽  
Morphological Data ◽  
Ancestral State ◽  
Transcriptome Data ◽  
Large Size ◽  
The Family ◽  
History Of ◽  
Almost All ◽  
First Time

Mygalomorph spiders of the family Theraphosidae, known to the broader public as tarantulas, are among the most recognizable arachnids on earth due to their large size and widespread distribution. Their use of urticating setae is a notable adaptation that has evolved exclusively in certain New World theraphosids. Thus far, the evolutionary history of Theraphosidae remains poorly understood; theraphosid systematics still largely relies on morphological datasets, which suffer from high degrees of homoplasy, and traditional targeted sequencing of preselected genes failed to provide strong support for supra-generic clades (i.e. particularly those broader than subfamilies). In this study, we provide the first robust phylogenetic hypothesis of theraphosid evolution inferred from transcriptome data. A core ortholog approach was used to generate a phylogeny from 2460 orthologous genes across 25 theraphosid genera, representing all of the major theraphosid subfamilies, except Selenogyrinae. For the first time our phylogeny recovers a monophyletic group that comprises the vast majority of New World theraphosid subfamilies including Aviculariinae and Theraphosinae. Concurrently, we provide additional evidence for the integrity of questionable subfamilies, such as Poecilotheriinae and Psalmopoeinae, and support the non-monophyly of Ischnocolinae. The deeper relationships between almost all subfamilies are confidently inferred for the first time. We also used our phylogeny in tandem with published morphological data to perform ancestral state analyses on urticating setae. This revealed that the evolution of this important defensive trait might be explained by three equally parsimonious scenarios.

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