Island biogeography of tropical alpine floras

Abstract

Aim We analysed the effects of alpine area, geographical distance between mountains and isolation due to topography on mountain plant species richness, regional species turnover and patterns of species distribution.Location Equatorial mountains of East Africa, South America and New Guinea. MethodsWe collated lists of alpine species and estimated the extent of alpine area for seven mountains in each geographical region to construct species-area curves. We tested the observed frequency distribution of species among mountains against the expected distribution (assuming random dispersal) by means of a log-likelihood test. We compared species turnover among mountains using species accumulation curves. We expressed floristic similarity between mountain pairs as chi-square distance between observed and expected numbers of shared species and tested its correlation with geographical distance using the Mantel test.Results Samples of East African, South American and New Guinean alpine floras contained 371, 489 and 279 species, respectively. Andean genera tended to be more species rich than genera in the other regions. Species richness of the mountains correlated with log-transformed area except in East Africa. Species distributions among mountains significantly deviated from random in all regions. Species turnover was lowest among East African sites and highest among South American sites, and the slopes of the cumulative species-area relationship were significantly different. Floristic similarity between mountains significantly declined with log(distance) in all regions, and the slope of the relationship was steepest in South America.Main conclusions The flora of the Andean p aramo is confirmed to be the most species rich of the tropical alpine regions. P aramo genera tend to be richer in species than afroalpine and tropicalpine Asian genera. There is higher species turnover in the Andes and the floras of individual mountains are therefore quite distinct. In contrast, the floras of the East African mountains are more uniform and possess a relatively large number of widespread species.

Eco-geographical factors affecting richness and phylogenetic diversity patterns of high-mountain flora in the Iberian Peninsula

“…Several studies have shown the relationship between species richness and isolation, both in island ecosystems (Gillespie et al 2013;Karger et al 2014) and mountains (Gehrke and Linder 2014;Sklenář et al 2014). In our case, this relationship is only significant for the endemic element, where high species richness is a result of allopatric speciation after immigration, and suggests that the general patterns can change according to different evolutionary histories.…”

Identifying temporal and spatial patterns of diatom community change in the tropical Andes over the last c. 150 years

“…Climatic conditions in inter Andean plateau are generally drier than the high Andes (MAT = 13.2°C; MAP = 839 mm), with a higher percentage of pastoralism, crops and towns. Despite present‐day threats associated with tourism and population growth, as well as global climate change (Bradley, Vuille, Diaz, & Vergara, ), Ecuadorean Andean lakes and their basins are good representatives of tropical high‐mountain ecosystems and are unique biodiversity reservoirs (Sklenář, Hedberg, & Cleef, ).…”

Frequent colonization and little in situ speciation in Senecio in the tropical alpine‐like islands of eastern Africa

“…Little diversifi cation in the tropical Afroalpine contrasts strongly with fi ndings for the tropical alpine-like Páramo regions of the South American Andes (broadly the northern parts of the Andes; ranging from 10 ° N to 10 ° S; Sklenář et al, 2011 ;Gehrke and Linder, 2014 ;Sklenář et al, 2014 ). Diff erences in in situ speciation between the Páramo and the tropical Afroalpine can be observed in Senecio .…”

“…Th ere exists one supported subclade ( S. campanulatus-S. hypsobates ) of the New World 1 clade as sampled by Pelser et al (2007) and expanded by Dušková et al (2010) that contains 14 species predominantly occurring in alpine-like conditions (plus three montane species) of the northern Andes ( Luteyn and Churchill, 1999 ). Altogether, in situ speciation is likely to be higher in the Páramo than in EA for Senecio species because although both alpine-like fl oras are of similar age, species richness in general and within particular clades is higher in the Páramo ( Sklenář et al, 2014 ). High speciation rates were reported for, e.g., Andean Gentianella Moench, Halenia Borkh., Hypericum L., and Lupinus L. ( Kadereit and von Hagen, 2003 ;Drummond et al, 2012b ;Nürk et al, 2013 ).…”