Integrating demography and distribution modeling for the iconic Leontopodium alpinum Colm. in the Romanian Carpathians.

Lăcrămioara M Maghiar,Ilie A Stoica,Andrew J Tanentzap

doi:10.1002/ece3.7864

Abstract

Both climate change and human exploitation are major threats to plant life in mountain environments. One species that may be particularly sensitive to both of these stressors is the iconic alpine flower edelweiss (Leontopodium alpinum Colm.). Its populations have declined across Europe due to over‐collection for its highly prized flowers. Edelweiss is still subject to harvesting across the Romanian Carpathians, but no study has measured to what extent populations are vulnerable to anthropogenic change.Here, we estimated the effects of climate and human disturbance on the fitness of edelweiss. We combined demographic measurements with predictions of future range distribution under climate change to assess the viability of populations across Romania.We found that per capita and per‐area seed number and seed mass were similarly promoted by both favorable environmental conditions, represented by rugged landscapes with relatively cold winters and wet summers, and reduced exposure to harvesting, represented by the distance of plants from hiking trails. Modeling these responses under future climate scenarios suggested a slight increase in per‐area fitness. However, we found plant ranges contracted by between 14% and 35% by 2050, with plants pushed into high elevation sites.Synthesis. Both total seed number and seed mass are expected to decline across Romania despite individual edelweiss fitness benefiting from a warmer and wetter climate. More generally, our approach of coupling species distribution models with demographic measurements may better inform conservation strategies of ways to protect alpine life in a changing world.

Highlights

Climate change threatens many alpine plants, especially those with relatively narrow environmental niches (Gottfried et al, 2012; Pauli et al, 2012)
We found that per capita and per-area seed number and seed mass were promoted by both favorable environmental conditions, represented by rugged landscapes with relatively cold winters and wet summers, and reduced exposure to harvesting, represented by the distance of plants from hiking trails
We tested how each of seed mass and number both per plot and per inflorescence varied with environmental favorability and human disturbance using generalized mixed-effects models fitted with the lmer function in R (Bates et al, 2015)

Summary

| INTRODUCTION

Climate change threatens many alpine plants, especially those with relatively narrow environmental niches (Gottfried et al, 2012; Pauli et al, 2012). Species distribution models (SDMs) can help predict how climate change and other human-induced threats will impact the future range dynamics of alpine plants (Bakkenes et al, 2002; Casalegno et al, 2010; Thuiller et al, 2005), but these approaches rarely consider the capacity of populations to regenerate and persist in space. We focus on identifying the relative importance of climate and human disturbance for the persistence of edelweiss (Leontopodium alpinum, Asteraceae), one of the most iconic flowers of Europe's mountains. We surveyed both seed mass and seed number at seven sites along a 275 km transect across Romania. Our work builds upon an emerging consensus for the need to link projections of future species distributions with key demographic processes to forecast better the potential impact of global change on species distributions (Fordham et al, 2013; Normand et al, 2014; Swab et al, 2015)

| MATERIALS AND METHODS

Findings

| DISCUSSION