@article{BareitherScheffelMetz2017,
  author    = {Bareither, Nils and Scheffel, Andre and Metz, Johannes},
  title     = {Distribution of polyploid plants in the common annual Brachypodium distachyon (s.l.) in Israel is not linearly correlated with aridity},
  series = {Israel Journal of Plant Sciences},
  volume    = {64},
  journal   = {Israel Journal of Plant Sciences},
  publisher = {Taylor \& Francis},
  address   = {London},
  issn      = {0792-9978},
  pages     = {83 -- 92},
  year      = {2017},
  abstract  = {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.},
  language  = {en}
}
@article{KurzeBareitherMetz2017,
  author    = {Kurze, Susanne and Bareither, Nils and Metz, Johannes},
  title     = {Phenology, roots and reproductive allocation, but not the LHS scheme, shape ecotypes along an aridity gradient},
  series = {Perspectives in plant ecology, evolution and systematics},
  volume    = {29},
  journal   = {Perspectives in plant ecology, evolution and systematics},
  publisher = {Elsevier},
  address   = {Jena},
  issn      = {1433-8319},
  doi       = {10.1016/j.ppees.2017.09.004},
  pages     = {20 -- 29},
  year      = {2017},
  abstract  = {This study tested systematically at two spatial scales for key traits shaping within-species ecotypic differentiation under increasing aridity. It assessed different plant strategy theories and considered potential implications for climate change. We studied the widespread Mediterranean grass Brachypodium hybridum. At large scale, we tested 14 populations along a steep natural aridity gradient (114-954 mm annual rainfall). At small scale, we tested the microclimatic contrast between plants originating from corresponding north (more mesic) and south (more arid) exposed hillslopes. Fifteen traits were measured in the greenhouse, including the popular traits of the LeafHeight- Seed scheme (SLA, plant height, seed mass), several traits on phenology, architecture, growth, fitness, and rarely measured root traits. Clear trait shifts indicated ecotypic differentiation along the large-scale gradient. Earlier phenology, higher reproductive allocation and reduced root investment characterized arid ecotypes. Surprisingly, no trait of the Leaf-Height-Seed scheme shifted with aridity and root responses were opposite to the theory of optimal resource partitioning. Trait differences between north and south exposures were small, often inconsistent between sites, and poorly matched the trends across the large-scale gradient. South exposures thus appeared unlikely to harbour distinct ecotypes better adapted to aridity. Our findings highlight ecotypes as a crucial way how species span environmental gradients, yet underpinning their restriction at small spatial scales. In combination, this possibly renders populations more vulnerable to climate change. We draw attention to specific, partly unexpected traits and pose the question whether the LeafHeight- Seed scheme has limited applicability for intraspecific investigations in drylands.},
  language  = {en}
}
@misc{BareitherScheffelMetz2017,
  author    = {Bareither, Nils and Scheffel, Andr{\´e} and Metz, Johannes},
  title     = {Distribution of polyploid plants in the common annual Brachypodium distachyon (s.l.) in Israel is not linearly correlated with aridity},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-395293},
  pages     = {10},
  year      = {2017},
  abstract  = {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.},
  language  = {en}
}