Dispersal limitations and long‐term persistence drive differentiation from haplotypes to communities within a tropical sky‐island: evidence from community metabarcoding

2021 ◽  
Author(s):  
Nancy Gálvez‐Reyes ◽  
Paula Arribas ◽  
Carmelo Andújar ◽  
Brent C. Emerson ◽  
Daniel Piñero ◽  
...  
Keyword(s):  
Dispersal Limitations ◽  
Sky Island

Response of Arizona cypress (Hesperocyparis arizonica) to the Horseshoe Two Megafire in a south-eastern Arizona Sky Island mountain range

2019 ◽  
Vol 28 (1) ◽  
pp. 62
Author(s):  
Andrew M. Barton ◽  
Helen M. Poulos
Keyword(s):  
Seedling Establishment ◽  
New World ◽  
Fire Severity ◽  
Mountain Range ◽  
High Severity ◽  
South West ◽  
Fire Intervals ◽  
Sky Island ◽  
Tecate Cypress

We examined the response of Arizona cypress (Hesperocyparis arizonica) to the 2011 Horseshoe Two Megafire in the Chiricahua Mountains, Arizona, USA. We documented cover type, fire severity, cypress mortality and seedling establishment in 60 plots. In plots subject to severe fire, most mature cypresses were killed, the canopy opened and seedlings established abundantly. These results were consistent across three canyons differing in topography and vegetation. Successful regeneration of Arizona cypress contrasts with low seedling establishment for pines in the same area after the Horseshoe Two Fire, a difference possibly explained by abundant serotinous seed production in cypress or its preference for riparian sites protected from extreme fire. Our results firmly establish Arizona cypress as a fire-sensitive but fire-embracing species that depends on stand-replacing fire for regeneration. Given the fire sensitivity of Arizona cypress, however, recent increases in the frequency of high-severity fires in the south-west USA could pose a threat to the long-term viability of this species by preventing individuals from reaching sexual maturity during fire intervals. This scenario, termed the ‘interval squeeze’, has been documented in tecate cypress (H. forbesii) in California. A drier future with more frequent wildfires could pose serious threats to all New World cypresses.

scholarly journals Dispersal limitations on fish community recovery following long-term water quality remediation

Hydrobiologia ◽  
2016 ◽  
Vol 771 (1) ◽  
pp. 45-65 ◽  
Author(s):  
Ryan A. McManamay ◽  
Robert T. Jett ◽  
Michael G. Ryon ◽  
Scott M. Gregory ◽  
Sally H. Stratton ◽  
...  
Keyword(s):  
Water Quality ◽  
Fish Community ◽  
Community Recovery ◽  
Dispersal Limitations ◽  
Water Quality Remediation

scholarly journals Adaptation, ancestral variation and gene flow in a ‘Sky Island’ Drosophila species

2020 ◽  
Author(s):  
Tom Hill ◽  
Robert L. Unckless
Keyword(s):  
Gene Flow ◽  
Recurrent Selection ◽  
Population History ◽  
Mountain Forests ◽  
Local Conditions ◽  
Immune Genes ◽  
The Face ◽  
Sky Island ◽  
Climate Crisis

AbstractOver time, populations of species can expand, contract, fragment and become isolated, creating subpopulations that must adapt to local conditions. Understanding how species maintain variation after divergence as well as adapt to these changes in the face of gene flow, is of great interest, especially as the current climate crisis has caused range shifts and frequent migrations for many species. Here, we characterize how a mycophageous fly species, Drosophila innubila, came to inhabit and adapt to its current range which includes mountain forests in southwestern USA separated by large expanses of desert. Using population genomic data from more than 300 wild-caught individuals, we examine four populations to determine their population history in these mountain forests, looking for signatures of local adaptation. We find D. innubila spread northwards during the previous glaciation period (30-100 KYA), and has recently expanded even further (0.2-2 KYA). D. innubila shows little evidence of population structure, consistent with a recent establishment and genetic variation maintained since before geographic stratification. We also find some signatures of recent selective sweeps in chorion proteins and population differentiation in antifungal immune genes suggesting differences in the environments to which flies are adapting. However, we find little support for long-term recurrent selection in these genes. In contrast, we find evidence of long-term recurrent positive selection in immune pathways such as the Toll-signaling system and the Toll-regulated antimicrobial peptides.

scholarly journals Co-invading ectomycorrhizal fungal succession in pine-invaded mountain grasslands

2021 ◽  
Author(s):  
Tomás Milani ◽  
Jason Hoeksema ◽  
Esteban Jobbágy ◽  
J Alejandro Rojas ◽  
Rytas Vilgalys ◽  
...  
Keyword(s):  
Fungal Spore ◽  
Pinus Elliottii ◽  
Fungal Communities ◽  
Grassland Soil ◽  
Mountain Grasslands ◽  
Spatial Isolation ◽  
Dispersal Limitations ◽  
Pinus Spp ◽  
Surrounding Soil

Pines (Pinus spp.) rely on co-introduced ectomycorrhizal (EM) fungi to invade native ecosystems in the Southern Hemisphere. Although co-invasive EM fungal communities are expected to be poor in species, long-term successional trajectories and the persistence of dispersal limitations are not well understood. We sampled the roots and surrounding soil of Pinus elliottii and P. taeda trees invading mountain grasslands of Argentina. We also sampled the EM fungal spore bank in grassland soil near (~150 m) and far (~850 m) from original pine plantations. We found an impressive total of 47 different co-invasive EM fungal OTUs. Differential dispersal capacities among EM fungi were detected in the spore bank of grassland soil, but not under mature invading pines. After thirty years of invasion, the age but not the degree of spatial isolation of pine individuals affected the EM fungal composition. We showed that invading pines can host a highly diverse EM fungal community and although dispersal limitations can be important during the colonization of non-invaded sites, they can be overcome in the life-span of pines, allowing EM succession to continue. These results enhance our understanding of the spatial structure and dispersal dynamics of EM fungi during pine invasions.

Therapy and prevention for mental health: What if mental diseases are mostly not brain disorders?

2019 ◽  
Vol 42 ◽  
Author(s):  
John P. A. Ioannidis
Keyword(s):  
Mental Health ◽  
Mental Disease ◽  
Brain Disorders ◽  
Social Stressors ◽  
Labor Education ◽  
Mental Diseases ◽  
Long Term Follow Up ◽  
Political Decisions

AbstractNeurobiology-based interventions for mental diseases and searches for useful biomarkers of treatment response have largely failed. Clinical trials should assess interventions related to environmental and social stressors, with long-term follow-up; social rather than biological endpoints; personalized outcomes; and suitable cluster, adaptive, and n-of-1 designs. Labor, education, financial, and other social/political decisions should be evaluated for their impacts on mental disease.

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter
Keyword(s):  
Working Memory ◽  
Rapid Serial Visual Presentation ◽  
Language Comprehension ◽  
Short Term Memory ◽  
Visual Presentation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

Brief summary of Kleť photographic search programme for minor planets

1999 ◽  
Vol 173 ◽  
pp. 189-192
Author(s):  
J. Tichá ◽  
M. Tichý ◽  
Z. Moravec
Keyword(s):  
Ccd Camera ◽  
Minor Planet ◽  
Minor Planets ◽  
Main Belt

AbstractA long-term photographic search programme for minor planets was begun at the Kleť Observatory at the end of seventies using a 0.63-m Maksutov telescope, but with insufficient respect for long-arc follow-up astrometry. More than two thousand provisional designations were given to new Kleť discoveries. Since 1993 targeted follow-up astrometry of Kleť candidates has been performed with a 0.57-m reflector equipped with a CCD camera, and reliable orbits for many previous Kleť discoveries have been determined. The photographic programme results in more than 350 numbered minor planets credited to Kleť, one of the world's most prolific discovery sites. Nearly 50 per cent of them were numbered as a consequence of CCD follow-up observations since 1994.This brief summary describes the results of this Kleť photographic minor planet survey between 1977 and 1996. The majority of the Kleť photographic discoveries are main belt asteroids, but two Amor type asteroids and one Trojan have been found.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

Long-term Cyclic Variations of Prominences, Green and Red Coronae over Solar Cycles

2000 ◽  
Vol 179 ◽  
pp. 201-204
Author(s):  
Vojtech Rušin ◽  
Milan Minarovjech ◽  
Milan Rybanský
Keyword(s):  
Emission Lines ◽  
High Latitudes ◽  
Green Line ◽  
Solar Cycles ◽  
The South ◽  
Coronal Emission ◽  
Local Maxima ◽  
The North ◽  
Cyclic Variations

AbstractLong-term cyclic variations in the distribution of prominences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18–23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the south branch a year later (2003), respectively. The local maxima of intensities in the green line show both poleward- and equatorward-migrating branches. The poleward branches will reach the poles around cycle maxima like prominences, while the equatorward branches show a duration of 18 years and will end in cycle minima (2007). The red corona shows mostly equatorward branches. The possibility that these branches begin to develop at high latitudes in the preceding cycles cannot be excluded.

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