Demographic responses of boreal-montane orchid Malaxis monophyllos (L.) Sw. populations to contrasting environmental conditions

Edyta Jermakowicz,Emilia Brzosko

doi:10.5586/asbp.3488

Abstract

In an age of changes in species’ geographical ranges, compounded by climatic and anthropogenic impacts, it become important to know which processes and factors influence plant populations and their persistence in the long term.Here we investigated dynamic and fitness components in twelve populations of Malaxis monophyllos (L.) Sw., situated in different geographical (regions) and ecological (type of habitat) units. Although M. monophyllos is a rare species, characterized by highly fragmented, boreal-montane distribution range, in last few decades it successfully colonized secondary habitats in Polish uplands. Our results indicate that M. monophyllos is represented mainly by small populations, which annual spatial and temporal changes might be very high, what affects the ephemeral character of these populations, regardless of the region and type of habitat. This dynamic structure, in turn, is caused by intensive exchange of individuals in populations, as well as by their short above-ground life span. Despite the large range of variation in size and reproductive traits, we can distinguish some regional patterns, which indicate boreal region as the most optimal for M. monophyllos growth and persistence in the long term, and with montane and upland/anthropogenic populations, due to lower reproductive parameters, as the most threatened. Although it should be considered that anthropogenic populations, despite their lower reproductive parameters and instability in the long term, present an intermediate, geographical and ecological character, therefore they may be valuable in shaping, both M. monophyllos’ future range, as well as its potential for response on ongoing and future changes. In general, reproduction is the main factor differentiating of M. monophyllos populations in regions, and we can suspect that it may become the cause of the future differentiation and isolation of these populations, occurring with progressive range fragmentation.

Highlights

Acquiring knowledge regarding within plant population processes and factors that influence population dynamics underpins reliable scientific knowledge based on modern conservation biology, and enables the prediction of species survival under changing environmental conditions [1]
Demographic changes in populations arise from the life histories of individuals which respond to selection caused by environmental changes [2,3,4], the investigation of population dynamics is important from the evolutionary point of view
The theory predicts that long life span and iterated reproduction is favored in stochastic environments [27], habitat-specialists with a short life span, low reproductive rates and huge demographic fluctuations are more endangered [10,28,29,30]

Summary

Introduction

Acquiring knowledge regarding within plant population processes and factors that influence population dynamics underpins reliable scientific knowledge based on modern conservation biology, and enables the prediction of species survival under changing environmental conditions [1]. The main globally important factors influencing plant species survival are human activity and climate changes [5,6,7,8], which are reflected at the individual and population levels [3,9,10,11]. The theory predicts that long life span and iterated reproduction is favored in stochastic environments [27], habitat-specialists with a short life span, low reproductive rates and huge demographic fluctuations are more endangered [10,28,29,30]

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Results

Conclusion