Introduction
Most mosses are poikilohydric and ectohydric, with limited ability to
regulate water loss, acquiring moisture and nutrients via external
conduction from surface water or dry deposition (rainfall, mist droplets
and airborne dust) (Proctor et al. 2007). In arctic, boreal and arid
ecosystems, prolific ground cover has enabled mosses to exert influence
on soil temperature and nitrogen availability, evapotranspiration and
vascular plant interactions (Belnap 2006; Betts et al. 1999; Bonan and
Shugart 1989; During and Tooren 1990; Gornall et al. 2007). It has been
suggested that mosses can be a potential source of nutrients and
moisture to vascular plants, supplying leaked nutrients from their cells
upon rehydration (Wilson and Coxson 1999), or possibly through
associations with mycorrhiza networks (Davey and Currah 2006). The moss
layer can also assist germinating seeds and seedlings, buffering harsh
abiotic conditions and providing camouflage against seed predation
(During and Tooren 1990; Rayburn et al. 2012). Conversely, mosses may
limit available resources to surrounding vascular plants by sequestering
nutrient precipitation inputs and accumulating organic matter
(Cornelissen et al. 2007). An association with cyanobacteria fixes
nitrogen which is retained by the moss rather than releasing it into the
soil (Rousk et al. 2016). In the arctic, alteration of soil temperature
and moisture have been shown to influence microbe activity and rates of
mineralisation and nitrification (Gornall et al. 2007).
The role of mosses in ecosystem function is complex and are often poorly
understood (Bond‐Lamberty et al. 2011; Chamizo et al. 2016) and research
surrounding the topic in New Zealand is almost entirely lacking (DeLucia
et al. 2003; Michel et al. 2013) in spite of mosses accounting for
>90% ground cover in many habitats (Pfeiffer 2003). Even
in some of the driest habitats mosses, and particularly Hypnum
cupressiforme , forms an almost continuous carpet, for example under
stands of the canopy shrub kānuka (Kunzea serotina , Myrtaceae) of
lowland New Zealand (Beever 1986; Macmillan 1976; Molloy and Ives 1972).
This research aimed to explore the role of the moss carpet within the
kānuka stands associated with ecological restoration of a dryland
habitat that has virtually disappeared from the contemporary irrigated
intensively-farmed landscapes of the lowland plains of eastern South
Island in New Zealand (Bowie et al. 2016). In view of their natural
ground cover prominence, it is likely that mosses have a functional role
in the restoration of these ecosystems. It is also possible that these
highly modified landscapes are unsuitable for the establishment of
mosses. This has perspectives both in terms of the possible
juxtaposition of these two land uses, and also whether restoration of
dryland habitat has a role in provision of ecosystem services.