What determines biogeographical ranges? Historical wanderings and ecological constraints in the danthonioid grasses

Abstract

Aim We sought to understand the variables that limit the distribution range of a clade (here the danthonioid grasses). We tested time, area of origin, habitat suitability, disjunction width and nature, and wind direction as possible range determinants. Location Global, but predominantly the Southern Hemisphere. Methods We mapped the range of the subfamily Danthonioideae, and used 39,000 locality records and an ensemble modelling approach to define areas with suitable danthonioid habitat. We used a well‐sampled, dated phylogeny to estimate the number and direction of historical dispersal events, based on parsimony optimization. We tested for the impact of wind direction on dispersal rate using a likelihood approach, and for the effects of barrier width with a regression approach. Results We found 17 geographically isolated areas with suitable habitats for danthonioids. All currently suitable Southern Hemisphere areas have been occupied, but three apparently suitable areas in the Northern Hemisphere have not. We infer that southern Africa was first occupied in the Oligocene and that dispersal to the other areas was initiated in the middle Miocene. Inferred dispersal rate was correlated with the width of the disjunctions, up to a distance of 5000 km. There was no support for wind direction having influenced differences in dispersal rate. Main conclusions The current range of the Danthonioideae can be predicted ecologically (areas with suitable habitat) and historically (the width of the disjunctions separating the areas with suitable habitat and the area of origin). The direction of dispersal is dictated by the area of origin and by serendipity: there is no evidence for general patterns of dispersal, for example for dispersal occurring more frequently over land than over sea or in an easterly versus a westerly direction around the Southern Hemisphere. Thus the range and range‐filling of Danthonioideae can be accounted for by surprisingly few variables: habitat suitability, distance between suitable areas, and area of origin.

Coordinated Dispersal and Pre-Isthmian Assembly of the Central American Ichthyofauna

“…The wa is introduced here as a standard metric to compare observed and expected rates of species-range expansion. This wa can also be used to compare quantitative dispersal rate estimates generated from biogeographic studies of different taxa across time and space, as for example, in the emerging fields of parametric biogeography (e.g., Landis et al 2013 ; Peter Linder et al 2013 ; Meseguer et al 2014 ) and invasion biology (e.g., Schurr et al 2012 ; Phillips 2012 ; Travis and Dytham 2012 ).…”

Evidence for recent evolution of cold tolerance in grasses suggests current distribution is not limited by (low) temperature

“…To estimate the realized temperature niches of the species in the common garden experiment, georeferenced occurrence data were obtained from herbarium records (Southern Hemisphere) and from the Global Biodiversity Information Facility (GBIF, www.gbif.org; for North American records; see R. O. W€ uest et al, unpublished;Linder et al, 2013). Temperature data for these localities were extracted from the WorldClim database (BIO1-BIO11; Hijmans et al, 2005) using ARCGIS 9.2 (ESRI, 2008.…”

Strong but opposing effects of climatic niche breadth and dispersal ability shape bat geographical range sizes across phylogenetic scales

“…Several hypotheses have been invoked to explain interspecific variations in species ranges. These can be broadly classified into extrinsic ones related to historical and biogeographical variables such as species ancestral ranges and time available for range expansion after speciation (Linder, Antonelli, Humphreys, Pirie, & Wüest, 2013;Paul, Morton, Taylor, & Tonsor, 2009), or intrinsic factors linked to species traits, such as diet, environmental tolerances, and their ability to colonize new regions (Slatyer, Hirst, & Sexton, 2013;Slove & Janz, 2011). Despite the evidences linking increased ranges due to the joint action of different processes, two intrinsic traits have been considered of particular importance in explaining interspecific variations in range sizes: species climatic niche breadths and dispersal abilities (Faurby & Antonelli, 2018;Gaston, 2003;Lester, Ruttenberg, Gaines, & Kinlan, 2007;Slatyer et al, 2013;Stevens, 1989).…”