39529
2017
2017
eng
10
postprint
1
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2017-03-21
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Distribution of polyploid plants in the common annual Brachypodium distachyon (s.l.) in Israel is not linearly correlated with aridity
The ecological benefits of polyploidy are intensely debated. Some authors argue that plants with duplicated chromosome sets (polyploids) are more stress-resistant and superior colonizers and may thus outnumber their low ploidy conspecifics in more extreme habitats. Brachypodium distachyon (sensu lato), for example, a common annual grass in Israel and the entire Mediterranean basin, comprises three cytotypes of differing chromosome numbers that were recently proposed as distinct species. It was suggested that increased aridity increases the occurrence of its polyploid cytotype. Here, we tested at two spatial scales whether polyploid plants of B. distachyon s.l. are more frequently found in drier habitats in Israel. We collected a total of 430 specimens (i) along a largescale climatic gradient with 15 thoroughly selected sites (spanning 114–954 mm annual rainfall), and (ii) from corresponding Northern (more mesic) and Southern (more arid) hill slopes to assess the micro-climatic difference between contrasting exposures. Cytotypes were then determined via flow cytometry. Polyploid plants comprised 90% of all specimens and their proportion ranged between 0% and 100% per site. However, this proportion was not correlated with aridity along the large-scale gradient, nor were polyploids more frequently found on Southern exposures. Our results show for both spatial scales that increasing aridity is not the principal driver for the distribution of polyploids in B. distachyon s.l. in Israel. Notably, though, diploid plants were restricted essentially to four intermediate sites, while polyploids dominated the most arid and the most mesic sites. This, to some degree, clustered pattern suggests that the distribution of cytotypes is not entirely random and calls for future studies to assess further potential drivers.
urn:nbn:de:kobv:517-opus4-395293
online registration
Israel journal of plant sciences (2017). - DOI: 10.1080/07929978.2017.1288406
CC-BY - Namensnennung 4.0 International
Nils Bareither
André Scheffel
Johannes Metz
Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
334
eng
uncontrolled
Aridity
eng
uncontrolled
Brachypodium distachyon
eng
uncontrolled
Brachypodium hybridum
eng
uncontrolled
Brachypodium stacei
eng
uncontrolled
cytotype
eng
uncontrolled
exposition
eng
uncontrolled
Israel
eng
uncontrolled
Mediterranean grass species
eng
uncontrolled
polyploidization
eng
uncontrolled
rainfall gradient
eng
uncontrolled
slope aspect
Pflanzen (Botanik)
open_access
Institut für Biochemie und Biologie
Referiert
Open Access
Taylor & Francis Open Access Agreement
Universität Potsdam
https://publishup.uni-potsdam.de/files/39529/pmnr334_online.pdf
1346
2006
eng
347
357
postprint
0
2007-07-11
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Opposite trends in life stages of annual plants caused by daily rainfall variability
Global Circulation Models of climate predict not only a change of annual precipitation amounts but also a shift in the daily distribution. To improve the understanding of the importance of daily rain pattern for annual plant communities, which represent a large portion of semi-natural vegetation in the Middle East, I used a detailed, spatially explicit model. The model explicitly considers water storage in the soil and has been parameterized and validated with data collected in field experiments in Israel and data from the literature. I manipulated daily rainfall variability by increasing the mean daily rain intensity on rainy days (MDI, rain volume/day) and decreasing intervals between rainy days while keeping the mean annual amount constant. In factorial combination, I also increased mean annual precipitation (MAP). I considered five climatic regions characterized by 100, 300, 450, 600, and 800 mm MAP. Increasing MDI decreased establishment when MAP was >250 mm but increased establishment at more arid sites. The negative effect of increasing MDI was compensated by increasing mortality with increasing MDI in dry and typical Mediterranean regions (c. 360–720 mm MAP). These effects were strongly tied to water availability in upper and lower soil layers and modified by competition among seedlings and adults. Increasing MAP generally increased water availability, establishment, and density. The order of magnitudes of MDI and MAP effects overlapped partially so that their combined effect is important for projections of climate change effects on annual vegetation. The effect size of MAP and MDI followed a sigmoid curve along the MAP gradient indicating that the semi-arid region (≈300 mm MAP) is the most sensitive to precipitation change with regard to annual communitie
interaction with climate change
urn:nbn:de:kobv:517-opus-14699
1469
UT 8900
Proceedings of the international conference on climate change and the middle east past, present and future : 20–23 November 2006, S. 347–357
Martin Köchy
deu
swd
Klimaänderung
deu
uncontrolled
Klimawandel
deu
uncontrolled
Einjahrespflanzen
deu
uncontrolled
Schwankung
deu
uncontrolled
tägliche Regenmenge
deu
uncontrolled
Israel
eng
uncontrolled
climate change
eng
uncontrolled
daily rainfall variability
eng
uncontrolled
annual plant
eng
uncontrolled
Israel
Biowissenschaften; Biologie
open_access
Institut für Biochemie und Biologie
Universität Potsdam
https://publishup.uni-potsdam.de/files/1346/pmnr229.pdf
1216
2006
eng
postprint
0
2007-05-07
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Stochastic time series of daily precipitation for the interior of Israel
This contribution describes a generator of stochastic time series of daily precipitation for the interior of Israel from c. 90 to 900 mm mean annual precipitation (MAP) as a tool for studies of daily rain variability. The probability of rainfall on a given day of the year is described by a regular Gaussian peak curve function. The amount of rain is drawn randomly from an exponential distribution whose mean is the daily mean rain amount (averaged across years for each day of the year) described by a flattened Gaussian peak curve. Parameters for the curves have been calculated from monthly aggregated, long-term rain records from seven meteorological stations. Parameters for arbitrary points on the MAP gradient are calculated from a regression equation with MAP as the only independent variable. The simple structure of the generator allows it to produce time series with daily rain patterns that are projected under climate change scenarios and simultaneously control MAP. Increasing within-year variability of daily precipitation amounts also increases among-year variability of MAP as predicted by global circulation models. Thus, the time series incorporate important characteristics for climate change research and represent a flexible tool for simulations of daily vegetation or surface hydrology dynamics.
urn:nbn:de:kobv:517-opus-13155
1315
Israel Journal of Earth Science. - 55 (2006), 2, p. 103 - 109. - ISSN: 0021-2164
<hr>This paper was first published in:<br><a href="http://www.sciencefromisrael.com/(n02fy055zjxjmu450n1woa45)/app/home/journal.asp?referrer=parent&backto=homemainpublications,2,5;" target=_blanc> Israel Journal of Earth Science</a>, 55 (2006), 2, p. 103 - 109<br>ISSN 0021-2164<br>DOI: <ahref="http://dx.doi.org/10.1560/IJES_55_2_103" target=_blanc>10.1560/IJES_55_2_103 </a>
Martin Köchy
Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
paper 029
deu
uncontrolled
stochastische Zeitreihen
deu
uncontrolled
täglicher Niederschlag
deu
uncontrolled
Israel
deu
uncontrolled
Klimawandel
eng
uncontrolled
stochastic time series
eng
uncontrolled
daily precipitation
eng
uncontrolled
Israel
eng
uncontrolled
climate change
Naturwissenschaften und Mathematik
open_access
Institut für Biochemie und Biologie
Universität Potsdam
https://publishup.uni-potsdam.de/files/1216/Koechy2006.pdf