Rules of Plant Species Ranges: Applications for Conservation Strategies

Abstract

Earth is changing rapidly and so are many plant species’ ranges. Here, we synthesize eco-evolutionary patterns found in plant range studies and how knowledge of species ranges can inform our understanding of species conservation in the face of global change. We discuss whether general biogeographic “rules” are reliable and how they can be used to develop adaptive conservation strategies of native plant species across their ranges. Rules considered include (1) factors that set species range limits and promote range shifts; (2) the impact of biotic interactions on species range limits; (3) patterns of abundance and adaptive properties across species ranges; (4) patterns of gene flow and their implications for genetic rescue, and (5) the relationship between range size and conservation risk. We conclude by summarizing and evaluating potential species range rules to inform future conservation and management decisions. We also outline areas of research to better understand the adaptive capacity of plants under environmental change and the properties that govern species ranges. We advise conservationists to extend their work to specifically consider peripheral and novel populations, with a particular emphasis on small ranges. Finally, we call for a global effort to identify, synthesize, and analyze prevailing patterns or rules in ecology to help speed conservation efforts.

Genetic survey extension of the threatened Iberian Arnica montana L. revealed the presence of divergent plastid lineages and highly structured populations in northern Spain

“…Values of genetic diversity across the studied Northern Iberian region Historical and recent processes shape the genetic variation and population differentiation present in natural populations (Maroso et al 2021). Maintenance of genetic diversity can be a challenge for populations located at the limits of the species range because isolation and extinction/colonization events are frequent (Cires et al 2011), but these populations can retain singular variants of high interest for conservation (Travis and Dytham 2004;Shay et al 2021) and their human use should be rational and controlled. Arnica montana populations in the Iberian Peninsula represent the southern edge of the natural distribution of the species (Falniowski et al 2013).…”

Genomic Analyses of Wild and Cultivated Bacanora Agave (Agave angustifolia var. pacifica) Reveal Inbreeding, Few Signs of Cultivation History and Shallow Population Structure

“…Another important factor affecting plant population genetic structure is spatial distribution [ 1 , 15 ]. Plant species can occur in uniform, clumped, or random distributions, or, for instance, along an elevation gradient; and the ranges of species may vary in size from widespread to very narrow and endemic.…”

Range Size and Niche Breadth as Predictors of Climate-Induced Habitat Change in Epipactis (Orchidaceae)

“…It is expected that species which have narrow temperature or precipitation tolerances are the most likely to be affected by climate change (Slatyer et al, 2013). However, empirical evidence is still limited (Shay et al, 2021) and for many species we do not know the factors that limit their distributions, whether leading edge expansions are sustainable, or how these species respond to climate change. Gaining a better understanding of the physical factors underlying the distribution of organisms is crucial to predict how species will respond to climate change (Hagsater et al, 1996;Tsiftsis et al, 2008).…”

“…A recent modelling study has indeed shown that predicted changes in climatic conditions increased habitat suitability available to three Orchis species by 2050 at the northern edge of their distribution . However, given that these species showed very similar distribution areas and often co-occur, such a generalisation may not be appropriate and it remains unclear how differences in range size or environmental niche breadth predict vulnerability under global change (Shay et al, 2021).…”