Mono-specific forest plantations are valuable bat habitats: implications for wind energy development

Sascha Buchholz,Simon J Ghanem,Volker Kelm

doi:10.1007/s10344-020-01440-8

Abstract

Near-natural or semi-natural forests such as relatively undisturbed and old deciduous or mixed woodland are considered worth protecting and ecologically valuable habitats for bat conservation. In contrast, mono-specific forest plantations are considered ecologically less valuable; thus, decision-makers recommend these plantations as suitable locations for wind power stations and therefore want to further expand wind turbines in these habitats. This is expected to have a strong negative impact on the landscape because forests would be cleared for wind turbine pads and access roads and wind turbines rise above the trees with adverse impacts for bats. Therefore, we argue that, in light of bat conservation, the suitability of forest plantations for wind energy development is not, per se, warranted and that implications of wind power stations, even in mono-specific forest plantations, should be assessed and evaluated. We conducted long-term bat activity monitoring and recorded bat echolocation calls above the canopies of different forest sites (coniferous monoculture plantations and semi-natural mixed deciduous forests) in Germany and compared different forest types in terms of species richness, total bat activity, activity of the three bat species groups and species composition. Generalised linear models revealed that forest type and the amount of forest biotopes did not enhance bat activity. Ordination showed that species composition was not affected by forest type, location and connectivity. Mono-specific forest plantations can harbour a diverse bat fauna with high species activity and are, therefore, valuable bat habitats just as near-natural or semi-natural woodlands are. Environmental impact assessment and mitigation measures are vital in all forest types before and after planning for wind energy turbines. In particular, future planning and approval processes must consider the importance of mono-specific forest plantations for bat species protection.

Highlights

Woodlands are vital for many bat species by providing habitats, roosting sites and hunting grounds (e.g. Jantzen and Fenton 2013; Kalda et al 2015; Charbonnier et al 2016a)
Most frequent were Nyctalus noctula, Pipistrellus pipistrellus, Pipistrellus pygmaeus and Pipistrellus nathusii that occurred at all study sites
Generalised linear models revealed that total bat activity (Chi2 = 1.56, P = 0.20, generalised linear models (GLM)) and number of bat species (Chi2 = 0.65, P = 0.42, GLM) in coniferous plantations and mixed deciduous forests did not differ significantly (Fig. 1)

Summary

Introduction

Woodlands are vital for many bat species by providing habitats, roosting sites and hunting grounds (e.g. Jantzen and Fenton 2013; Kalda et al 2015; Charbonnier et al 2016a). Woodlands are vital for many bat species by providing habitats, roosting sites and hunting grounds Aside from open landscapes, woodlands are considered potential locations for wind power stations. In contrast to near-natural or semi-natural woodlands, mono-specific forest plantations are lower quality habitats for bats, and decisionmakers are recommending them for wind power stations (e.g. MUGV Brandenburg 2011). Decision-makers argue that mono-specific forest plantations—characterised by one tree species (pine in NE-Germany) (Klimo et al 2000)—are ecologically less valuable, as they emaciate the soil, are sensitive to windfall and pests and are less diverse in plant and animal species (Klimo et al 2000; MUGV Brandenburg 2011). Wind energy development in mono-specific forest plantations is seen as ecologically sound and, has become the focus of attention of wind power operators (BFN 2011). The general consensus is that the expansion of wind turbines in these plantations should be promoted landscape changes are associated with this (for instance cleared forests for wind turbine pads and access roads as, wind turbines above the remaining forest patches)

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Discussion

Conclusion