Bioclimatic regions influence genetic structure of four JordanianStipaspecies

Abstract

Strong environmental gradients can affect the genetic structure of plant populations, but little is known as to whether closely related species respond similarly or idiosyncratically to ecogeographic variation. We analysed the extent to which gradients in temperature and rainfall shape the genetic structure of four Stipa species in four bioclimatic regions in Jordan. Genetic diversity, differentiation and structure of Stipa species were investigated using amplified fragment length polymorphism (AFLP) molecular markers. For each of the four study species, we sampled 120 individuals from ten populations situated in distinct bioclimatic regions and assessed the degree of genetic diversity and genetic differentiation within and among populations. The widespread ruderals Stipa capensis and S. parviflora had higher genetic diversity than the geographically restricted semi-desert species S. arabica and S. lagascae. In three of the four species, genetic diversity strongly decreased with precipitation, while genetic diversity increased with temperature in S. capensis. Most genetic diversity resided among populations in the semi-desert species (Φ(ST) = 0.572/0.595 in S. arabica/lagascae) but within populations in the ruderal species (Φ(ST) = 0.355/0.387 S. capensis/parviflora). Principal coordinate analysis (PCoA) and STRUCTURE analysis showed that Stipa populations of all species clustered ecogeographically. A genome scan revealed that divergent selection at particular AFLP loci contributed to genetic differentiation. Irrespective of their different life histories, Stipa species responded similarly to the bioclimatic gradient in Jordan. We conclude that, in addition to predominant random processes, steep climatic gradients might shape the genetic structure of plant populations.

Local adaptation to different phytogeographic regions: habitat‐related variations in seed germination in response to temperature and salinity for two medicinalSalviaspecies fromJordan

“…Moreover, steep climatic gradients might shape the genetic structure of plant populations (Hamasha et al . ), which is supported by the differences in germination ability between the two Salvia species under winter temperatures, as S. syriaca populations have limited distribution in the Saharo‐Arabian region.…”

Morphological and Genetic Variation along a North-to-South Transect in Stipa purpurea, a Dominant Grass on the Qinghai-Tibetan Plateau: Implications for Response to Climate Change

“…2013 [40]; Hamasha et al . 2013 [41]). The high level of genetic variability within populations of S .…”

Genetic diversity, outcrossing rate, and demographic history along a climatic gradient in the ruderal plant Ruellia nudiflora (Acanthaceae)

“…Thus, a strong founder effect, which is related to genetic bottlenecks in recently formed populations, is to be expected (Austerlitz, Jung-Muller, Godelle, & Gouyon, 1997;Bossdorf et al, 2005). Despite this prediction, the genetic diversity observed in ruderal and invasive plant species is usually not low (Bossdorf et al, 2005;Hamasha et al, 2013;Mandák, Zákravsky, Korínková, Dostál, & Placková, 2009). This agrees with our findings in R. nudiflora which show no evidence of genetic erosion, although θ 0 values showed populations starting with a few dozen individuals, large demographic expansion occurred in a short period of time.…”

“…This database uses historical records from 1950 to 2000 (Table 1) and provides weather surfaces from which global climate data with a spatial resolution of approximately 1 km 2 can be extracted. Mean temperature and precipitation were selected since these variables have been reported to influence genetic diversity and structure in ruderal plants (Hamasha et al, 2013). For each population, the surrounding vegetation type was characterized according to Duch-Gary (1988) (Table 1).…”

“…In contrast, very little is known about the outcrossing rate, demographic status, and demographic expansion of these species. However, there is evidence that bioclimatic heterogeneity influences genetic diversity and structure in ruderal plants, and has even been found to have a selective effect on some genetic markers (Hamasha, Schmidt-Lebuhn, Durka, Schleuning, & Hensen, 2013 and references therein).…”