Arctic, Antarctic, and Alpine Research An Interdisciplinary Journal ISSN: 1523-0430 (Print) 1938-4246 (Online) Journal homepage: https://www.tandfonline.com/loi/uaar20 Ecological Responses to 52 Years of Experimental Snow Manipulation in High-Alpine Cushionfield, Old Man Range, South-Central New Zealand Alan F. Mark, Annika C. Korsten, D. Urrutia Guevara, Katharine J. M. Dickinson, Tanja Humar-Maegli, Pascale Michel, Stephan R. P. Halloy, Janice M. Lord, Susanna E. Venn, John W. Morgan, Peter A. Whigham & Jacqueline A. Nielsen To cite this article: Alan F. Mark, Annika C. Korsten, D. Urrutia Guevara, Katharine J. M. Dickinson, Tanja Humar-Maegli, Pascale Michel, Stephan R. P. Halloy, Janice M. Lord, Susanna E. Venn, John W. Morgan, Peter A. Whigham & Jacqueline A. Nielsen (2015) Ecological Responses to 52 Years of Experimental Snow Manipulation in High-Alpine Cushionfield, Old Man Range, South-Central New Zealand, Arctic, Antarctic, and Alpine Research, 47:4, 751-772, DOI: 10.1657/ AAAR0014-098 To link to this article: https://doi.org/10.1657/AAAR0014-098 © 2015 Regents of the University of Published online: 05 Jan 2018. Colorado Submit your article to this journal Article views: 200 View related articles View Crossmark data Citing articles: 1 View citing articles Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=uaar20 Arctic, Antarctic, and Alpine Research, Vol. 47, No. 4, 2015, pp. 751–772 Ecological responses to 52 years of experimental snow manipulation in high-alpine cushionfield, Old Man Range, south-central New Zealand Alan F. Mark1,9 Abstract Annika C. Korsten1 Periodic monitoring over 52 years have revealed temporal changes in the vegetation and D. Urrutia Guevara1 floristic patterns associated with what has been acclaimed to be the world’s oldest known experimental snow fence, which is located on an exposed high-alpine cushionfield on the 1 Katharine J. M. Dickinson Old Man Range in south-central New Zealand. The induced pattern of intermittent snow- Tanja Humar-Maegli1,2 lie has been increased by the fence from the normal ~140 days to more than 200 days (and Pascale Michel1,3 up to 140 cm deep), estimated from subsurface soil temperatures, together with periodic observations and measurements of snow depth. Some but not all species associated with 1,4 Stephan R. P. Halloy natural snowbanks on the range have established in areas of induced snow accumulation. Janice M. Lord1 The timing of species establishment was not obviously related to relevant features of the Susanna E. Venn5,6 local snowbank species or their distribution on the range, but the abundance of various plant species and their functional traits across zones of snowmelt point to competition 5 John W. Morgan and plant productivity being associated with the deepest snow in the lee of the fence. In Peter A. Whigham7 and addition, three of the several measured physical and chemical soil factors (Mg, available 1,8 PO 3–, and C:N) have differentiated significantly in relation to the vegetation and snow-lie Jacqueline A. Nielsen 4 pattern at year 52, although these seem not to be relevant on the basis of the pattern of the same factors in two nearby natural snowbanks on the range. 1Alpine Ecosystems Research Group, Department of Botany, University of Otago, P.O. Box 56, Dunedin, 9054, New Zealand 2Present address: Meteotest, Fabrikstrasse 12, 3012 Bern, Switzerland 3Biodiversity and Conservation team, Manaaki Whenua-Landcare Research, P.O. Box 10 345, The Terrace, Wellington 6143, New Zealand 4Present address: Universidad Nacional de Chilecito, La Rioja, Argentina 5Centre for Applied Alpine Ecology, Department of Botany, La Trobe University, Bundoora, Victoria, 3086, Australia 6Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia 7Department of Information Science, University of Otago, P.O. Box 56, Dunedin, 9054, New Zealand 8Present address: 11860 Bayport Lane, Apartment 4, Fort Myers, Florida 33908, U.S.A. 9Corresponding author: [email protected] DOI: http://dx.doi.org/10.1657/AAAR0014-098 Introduction a strong relationship between duration of snow-lie and plant com- munity structure and composition (Mark and Bliss, 1970; Hadley Snow cover and its duration are among the most important and Rosen, 1974; Burrows, 1977a, 1977b; Talbot et al., 1992; Ban- factors controlling microenvironments and habitat conditions in nister et al., 2005), as with many studies abroad. the alpine zone, globally (Bliss, 1963; Gjaerevoll, 1956, 1965; One aspect of research on the effects of climate change con- Helm, 1982; Gibson and Kirkpatrick, 1985; Isard, 1986; Kudo cerns the ecological effects of predicted changes in the duration of and Ito, 1992; Walker et al., 1993; Grabherr, 1997; Körner, 2003; winter snow cover. Several empirical studies have involved design- Björk and Molau, 2007). New Zealand studies to date have shown ing fencing systems to experimentally alter snow cover (Walker © 2015 Regents of the University of Colorado ALAN F. MARK ET AL. / 751 1523-0430/12 $7.00 et al., 2001). A recent review of such studies by Wipf and Rixen these results with those from three separate studies of natural snow (2010) has ranked an experimental snow fence built in 1959 at banks on the range (Mark and Bliss, 1970; Korsten, 2011; Guevara, 1650 m elevation in exposed high-alpine cushionfield near the crest 2012). Although snow fences are not uncommon in alpine regions of the Old Man Range (1682 m), south-central New Zealand, as abroad, most have been built to manage drifting snow for various one of the oldest continuously running snow ecology experiments purposes, and relatively few have been purpose built for studying in Arctic and alpine ecosystems. the ecological effects of artificially manipulating snow depth and The fence was originally built as part of a study to retain addi- the duration of snow-lie, according to Wipf and Rixen (2010), who tional snow and augment water discharge into its catchment, used credit our study as the longest on record by 15 years. downstream for both irrigation and hydroelectric generation. Sev- eral seedlings of five subalpine North American tree species (Pinus contorta, P. flexilis, P. aristata, Picea engelmanni, and Abies lasio- Methods carpa) were planted behind the fence and alongside it to the north STUDY SITE in 1961, as well as at four lower elevation sites on the mountain, to assess their potential. Only P. contorta established but remained The snow fence was built at 45°19′31″S, 169°11′50″E and dwarfed and nonreproductive at the snow fence site, and these were 1650 m elevation, on the upper western slope of the Old Man removed with minimum disturbance together with all plants from Range (1682 m) (Fig. 1), which, like the other block-faulted high the other sites in March 1974 to assess their performance. Despite plateau mountains of Central Otago, is characterized by relatively its effectiveness, no other fences were built (Harrison, 1986a, low summer temperatures, near-freezing mean annual air tempera- 1986b). Located on the upper windward slope of the range, the 12 ture, frequent freeze-thaw cycles throughout the five-month grow- × 2 m fence is made of 100 × 25 mm wooden slats placed vertically ing season, very strong westerly winds, and a persistent winter at 50% density and set at 7° off-vertical angle. It is aligned across a snow cover (see Mark, 1994, and references therein). gentle (~5°) slope, normal to the prevailing westerly (SW to NW) winds (Fig. 1). A netting fence, built around the site in 1961 (6 m windward and 30 m leeward) to exclude sheep, was removed in SNOW-LIE PATTERNS AND SOIL TEMPERATURES 1998 when the area became conservation land and grazing stock We used snow depth data as recorded by Smith (Smith, 1991; were removed. Smith et al., 1995) with a graduated stake on a 3 × 2 m grid cover- Since its construction, periodic monitoring of the surrounding ing the 50 × 30 m study site; he also measured wind speed with a vegetation (up to 2011: year 52) has shown that the presence of the handheld anemometer at 15 cm height at each of his 100 quadrat snow fence has modified the cushionfield vegetation in its vicinity. In locations (Smith, 1991). In addition, we photographed the snow the initial study, Harrison (1986b) reported on both the drift pattern pattern periodically (Fig. 1), and measured its depth on 20 October (based on a central transect perpendicular to the fence) and the dura- 2004, also on a 3 × 2 m grid, but over the reduced (30 × 20 m) study tion and density of the drifted snow, in addition to initial observations site (122 grid intersections), using a surveyor’s level and graduated of the snow-lie pattern. He reported the snow drift in October 1976 was staff (Fig. 2). The ground surface profile was similarly measured 21 m in length with the greatest snow depth (2.1 m) occurring within when the site was snow-free. 12 m of the fence. The snow density was somewhat greater within The number of days with snow cover was derived from subsur- the pack (500 kg m–3) than at nearby control sites (est. 450 kg m–3) face (–1 cm) and soil (–10 cm) temperatures as measured over two (Harrison, 1986b), although both conform with “old snow” according years with two Campbell (Model CR-10) data loggers, installed in to Körner (2003, p. 47). Harrison (1986b) was the first to report on April 2003. Sensors were located at 3 m intervals along a transect, changes to the structure and composition of the alpine plant commu- bisecting the center of the snow fence from 5 m to its windward to nity in the immediate vicinity of the fence (based on point samples in 24 m to leeward (Fig.