Logo image
Drivers and constraints on floral latitudinal diversification gradients
Journal article   Peer reviewed

Drivers and constraints on floral latitudinal diversification gradients

Phillip E. Jardine, Guy J. Harrington, Jocelyn A. Sessa and Jirina Daskova
Journal of biogeography, v 45(6), pp 1408-1419
01 Jun 2018

Abstract

Ecology Environmental Sciences & Ecology Geography, Physical Life Sciences & Biomedicine Physical Geography Physical Sciences Science & Technology
Aim: The latitudinal diversity gradient (LDG) is a primary emergent property of the biosphere, yet the cause(s) of this pattern are still debated. Key to many hypotheses is the origins and maintenance of tropical hyperdiversity, and the role of climate in driving low latitude speciation. Here, we analyse patterns of tropical and extratropical floral diversification and migration during the early Palaeogene greenhouse interval, to shed further light on the relationship between climatic change, latitude and floral diversity. Location: The early Palaeogene, from similar to 63 to 42 million years ago, of the US Gulf Coastal Plain (GCP) and Colombia. Taxon; Terrestrial plants, using pollen and spores as a proxy. Methods: We analyse species diversity trends using coverage and sample size-based interpolation and extrapolation, Chao1 estimated richness, and evenness metrics. Capture-mark-recapture (CMR) modelling is used to estimate origination and extinction probabilities. Origination patterns on the GCP are separated into insitu speciation versus immigration. Results: While Colombian (tropical) palynofloral richness and origination rates increased in conjunction with warming, GCP richness remained stable. The single rise in GCP origination rates, coincident with the Palaeocene-Eocene Thermal Maximum, was largely driven by the immigration of Eurasian taxa, rather than insitu origination, which was the case in Colombia. Main conclusions: These results show that the relationships among climatic parameters and diversification and dispersal are not straightforward. While temperature may have driven diversification in the tropics, other factors, such as precipitation, insolation or biological interactions, may have constrained diversification in the extratropics. Furthermore, our results suggest that outward dispersal from the tropics was limited in the warm world of the early Palaeogene, with most GCP immigrants being sourced from other extratropical regions. These findings suggest that the tropics and extratropics may have functioned independently at this time.

Metrics

11 Record Views
9 citations in Scopus

Details

UN Sustainable Development Goals (SDGs)

This publication has contributed to the advancement of the following goals:

#13 Climate Action
#14 Life Below Water

InCites Highlights

Data related to this publication, from InCites Benchmarking & Analytics tool:

Collaboration types
Domestic collaboration
International collaboration
Web of Science research areas
Ecology
Geography, Physical
Logo image