Late Spring Frost in Mediterranean Beech Forests: Extended Crown Dieback and Short-Term Effects on Moth Communities

Silvia Greco,Stefano Scalercio,Maria Lanfredi,Vito Imbrenda,Tiziana Simoniello,Carlo De Donato,Rosa Coluzzi,Marco Infusino

doi:10.3390/f9070388

Abstract

The magnitude and frequency of Extreme Weather Events (EWEs) are increasing, causing changes in species distribution. We assessed the short-term effects of a late spring frost on beech forests, using satellite images to identify damaged forests and changes in v-egetation phenology, as well as to support the analyses on associated moth communities. The EWE caused crown dieback above 1400 m of altitude, recovered only after several weeks. Nine stands for moth sampling, settled in impacted and non-impacted forests, allowed us to study changes in moth communities and in the wingspan of the most impacted species. The EWE modified community structures, reducing the abundance of beech-feeder species, but leaving species richness unaltered. Operophtera fagata and Epirrita christyi, dominant before the EWE, lost 93% and 89% of their population, respectively. We found a general increase in the average wingspan for these species, caused by the loss of small specimens in most impacted forests, suggesting a re-colonization from non-impacted forests. According to our results, populations of some species could be more resilient than others after an EWE due to their different dispersal ability. Forest ecosystems appear to be dynamic entities able to cope with extreme weather events but, likely, only if they continue to occur in the future at the current rate.

Highlights

The relative importance of climate warming as a major driver of biodiversity and ecosystem changes is expected to increase in the future [1]
We compared the number of individuals (N) and species (S) before and after the Extreme Weather Events (EWEs), as a whole and partitioned into two guilds: beech feeders (BFs), which included species whose larvae can feed on beeches; and non-beech feeders (n-BFs), which included species whose larvae have other host plants
We found a significant difference between BF and n-BF medians only during 2015 (p = 0.013), as they were not significantly different during 2016 (p = 0.60), showing an increased relative importance of n-BFs within moth communities after the EWE

Summary

Introduction

The relative importance of climate warming as a major driver of biodiversity and ecosystem changes is expected to increase in the future [1]. The rate of change will likely exceed the ability of many species to adapt, amplifying the risk of cascading effects through ecosystem interactions. Over the past few decades, EWEs have caused serious economic/environmental damages [7], notably affecting ecosystems [8] and magnifying the negative impact of gradual warming on biodiversity [9,10,11]. The most tangible evidence of these climatic events is the alteration of species ranges due to extinctions and colonization processes, changing the structure of entire ecosystems [12,13]. The long-term consequences of climatic events appear to be detrimental, Forests 2018, 9, 388; doi:10.3390/f9070388 www.mdpi.com/journal/forests

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Discussion

Conclusion