Summer roosts of “The revenant” flat-headed myotis, Myotis planiceps

2020 ◽  
Author(s):  
María Paulina Núñez-Rojo ◽  
Joaquín Arroyo-Cabrales ◽  
Emmanuel Rivera-Téllez ◽  
Rodrigo A Medellín
Keyword(s):  
Strategic Planning ◽  
Chihuahuan Desert ◽  
Extinction Risk ◽  
Roosting Ecology ◽  
Mean Width ◽  
Myotis Myotis ◽  
The Dead

Abstract The flat-headed myotis (Myotis planiceps) was declared extinct in 1996 but rediscovered in 2004, thus the reference to a revenant, one who came back from the dead, as it was declared extinct in 1996 but rediscovered in 2004. However, the species still faces serious extinction risk. To aid in the strategic planning and priorities for conservation, we studied roosting ecology. These bats inhabit the Chihuahuan Desert in one of the smallest distributional ranges of any mammal. Using radiotelemetry, we located 25 summer roosts, all in the skirts of dry leaves of yucca trees (Yucca carnerosana). We conclude that to roost, these bats search for clumps of tall yucca trees with a mean height of 3.93 m and mean width of skirts of 1.35 m.

Thermoregulation of two sympatric species of horned lizards in the Chihuahuan Desert and their local extinction risk

2015 ◽  
Vol 48 ◽  
pp. 1-10 ◽  
Author(s):  
Rafael A. Lara-Reséndiz ◽  
Héctor Gadsden ◽  
Philip C. Rosen ◽  
Barry Sinervo ◽  
Fausto R. Méndez-De la Cruz
Keyword(s):  
Chihuahuan Desert ◽  
Extinction Risk ◽  
Sympatric Species ◽  
Local Extinction ◽  
Horned Lizards

scholarly journals Dioecy Is Associated with High Genetic Diversity and Adaptation Rates in the Plant Genus Silene

2020 ◽  
Author(s):  
Aline Muyle ◽  
Hélène Martin ◽  
Niklaus Zemp ◽  
Maéva Mollion ◽  
Sophie Gallina ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Genomics ◽  
Extinction Risk ◽  
Population Level ◽  
High Genetic Diversity ◽  
Geographic Ranges ◽  
Sexual Systems ◽  
Dead End ◽  
The Dead ◽  
Genus Silene

Abstract About 15,000 angiosperm species (∼6%) have separate sexes, a phenomenon known as dioecy. Why dioecious taxa are so rare is still an open question. Early work reported lower species richness in dioecious compared with nondioecious sister clades, raising the hypothesis that dioecy may be an evolutionary dead-end. This hypothesis has been recently challenged by macroevolutionary analyses that detected no or even positive effect of dioecy on diversification. However, the possible genetic consequences of dioecy at the population level, which could drive the long-term fate of dioecious lineages, have not been tested so far. Here, we used a population genomics approach in the Silene genus to look for possible effects of dioecy, especially for potential evidence of evolutionary handicaps of dioecy underlying the dead-end hypothesis. We collected individual-based RNA-seq data from several populations in 13 closely related species with different sexual systems: seven dioecious, three hermaphroditic, and three gynodioecious species. We show that dioecy is associated with increased genetic diversity, as well as higher selection efficacy both against deleterious mutations and for beneficial mutations. The results hold after controlling for phylogenetic inertia, differences in species census population sizes and geographic ranges. We conclude that dioecious Silene species neither show signs of increased mutational load nor genetic evidence for extinction risk. We discuss these observations in the light of the possible demographic differences between dioecious and self-compatible hermaphroditic species and how this could be related to alternatives to the dead-end hypothesis to explain the rarity of dioecy.

An Alternative Method for Identifying a Failed Engine in Twin-Engine Propeller Aircraft

2020 ◽  
Vol 10 (2) ◽  
pp. 103-111
Author(s):  
Andrey K. Babin ◽  
Andrew R. Dattel ◽  
Margaret F. Klemm
Keyword(s):  
Human Error ◽  
Flight Simulator ◽  
Traditional Group ◽  
Aircraft Accidents ◽  
Alternative Method ◽  
Indicator Group ◽  
Group A ◽  
The Dead ◽  
Engine Failure ◽  
And Performance

Abstract. Twin-engine propeller aircraft accidents occur due to mechanical reasons as well as human error, such as misidentifying a failed engine. This paper proposes a visual indicator as an alternative method to the dead leg–dead engine procedure to identify a failed engine. In total, 50 pilots without a multi-engine rating were randomly assigned to a traditional (dead leg–dead engine) or an alternative (visual indicator) group. Participants performed three takeoffs in a flight simulator with a simulated engine failure after rotation. Participants in the alternative group identified the failed engine faster than the traditional group. A visual indicator may improve pilot accuracy and performance during engine-out emergencies and is recommended as a possible alternative for twin-engine propeller aircraft.

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