The maritime Subantarctic: a distinct periglacial environment

Boelhouwers, Jan; Holness, Steve; Sumner, Paul

doi:10.1016/s0169-555x(02)00247-7

Cited by 78 publications

(130 citation statements)

References 24 publications

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“…The Sabbione basin is characterized by the presence of periglacial domain with a mean annual air temperature comprised between -1 and 3 ºC (French, 1996(French, , 2007; in particular, the basin is located in a permafrost environment, according to the definitions proposed by Guglielmin (2004), with MAAT below 0 ºC and rainfall below 2000 mm/year (André, 2003;Boelhouwers, 2003).…”

Section: Discussionmentioning

confidence: 99%

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Climate variations in a high altitude Alpine basin and their effects on a glacial environment (Italian Western Alps)

Giaccone¹,

Colombo²,

Acquaotta³

et al. 2015

Atmósfera

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El principal objetivo de este estudio es evaluar la variación de los parámetros climáticos (temperatura, lluvia y nieve) medidos en dos estaciones meteorológicas (Formazza y Sabbione) que nunca antes se habían analizado, ubicadas en un ambiente glaciar (la cuenca del Sabbione en los Alpes occidentales italianos). El estudio se centra en la evolución climática de la cuenca alpina durante los últimos 60 años : el cambio climático ha causado una declinación glaciar pronunciada cuyo origen es el aumento de la ablación debido principalmente al incremento de la temperatura del aire y la reducción de la alimentación, a su vez ocasionada periglaciares y ligadas al permafrost (p. ej., suelos estructurados y glaciares de roca) en depósitos de glaciares provenientes de la Pequeña Edad de Hielo (PEH), lo cual evidencia la transición de un ambiente glaciar/ la cuenca, se ha elaborado un mapa de la temperatura media anual del aire a partir de los análisis climáticos. ABSTRACTThe main objective of this study is to evaluate the variations of climatic parameters (temperature, rain and snow) measured by two weather stations (Formazza and Sabbione) that have never been analyzed before, located in a high glacial catchment (the Sabbione basin in the Italian Western Alps). The study highlights the climatic evolution of the Alpine basin during the last 60 years : climate change has caused a pronounced glacial decline originated by ablation augmentation, due mainly to increasing air temperatures and to reduced alimentation caused by a fresh snow decrease. The cross-correlation test shows that temperatures affect the glacial retreat dynamics more than snowfall. Periglacial and permafrost landforms (e.g., patterned the ongoing transition from glacial/proglacial to periglacial environments. Furthermore, in order to better identify the periglacial domain in the basin, a map of mean annual air temperature (MAAT) was produced based on climatic analysis.

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Section: Discussionmentioning

confidence: 99%

“…Guglielmin (2004) divides this domain, called "sensu lato" periglacial environment, in: (1) "sensu stricto" periglacial environment (MAAT between + 3 and 0 ºC), and (2) permafrost environment (MAAT < 0 ºC). Rainfall is less than 2000 mm/year (André, 2003;Boelhouwers, 2003).…”

Section: Introductionmentioning

confidence: 99%

Climate variations in a high altitude Alpine basin and their effects on a glacial environment (Italian Western Alps)

Giaccone¹,

Colombo²,

Acquaotta³

et al. 2015

Atmósfera

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“…The Tafelberg area is underlain by pre-glacial grey basalts. Surface material consists of a matrix-supported, unsorted glacial till and experiences c. 60 diurnal frost cycles in the upper 5 cm of soil (Holness, 2001a;Boelhouwers et al, 2003). Frequent needle ice formation results in frost heave and creep of up to 20 cm a − 1 (Boelhouwers et al, 2000;Holness, 2001a;Boelhouwers et al, 2003;Holness, 2003).…”

Section: Study Area and Site Selectionmentioning

confidence: 99%

“…For example, by colonising loose and exposed substrates (Huntley, 1972;Frenot et al, 1998), these cushion plants affect slope stability and improve substrate nutrient and moisture status (Huntley, 1971;Holness, 2004;Smith and Mucina, 2006). Furthermore, Azorella cushions are considered to influence frost creep and other sediment movement processes and play an important role in the formation of terraces and lobes (Holness and Boelhouwers, 1998;Boelhouwers et al, 2003). Marion Island is experiencing rapid and significant large-scale climate change (Smith, 2002;Le Roux and McGeoch, 2008a) and a thorough understanding of these biogeomorphological interactions is thus especially important.…”

Section: Introductionmentioning

confidence: 99%

“…Although mid-latitude marine environments, such as the islands of the sub-Antarctic, also experience diurnal frost cycles, these frost environments differ markedly from those of tropical alpine mountain systems. For example, on Marion Island, small, diurnal and seasonal temperature ranges of 1.9°C and 3.6°C respectively (Smith, 2002) are conducive to rapid transitions in freeze/ thaw cycle frequency and intensity under changing temperature regimes that render them especially sensitive to climate change (Boelhouwers, 2003;Boelhouwers et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

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Interactions between a cushion plant (Azorella selago) and surface sediment transport on sub-Antarctic Marion Island

2009

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a b s t r a c t a r t i c l e i n f oOn sub-Antarctic Marion Island cushions of the dominant vascular plant species, Azorella selago, interact with the geomorphology of fellfield landscapes by affecting sediment distribution and ultimately terrace formation. Here, to understand the consequences of Azorella cushions for substrate movement and sorting, we quantified the size and shape of Azorella cushions and the grain size distribution of sediment surrounding these cushions, using a combination of image analysis approaches. Results show that as cushions become larger, they tend to become more elongated and grow more perpendicular to the slope. Mean and variance of grain size were greater upslope of Azorella cushions, while the number of particles was higher downslope of cushions, although these differences were not significant at all sites studied. Differences between upslope and downslope particle sizes were, however, not related to cushion elongation or growth angle as had been expected. The observed sediment partitioning is likely caused by a combination of frost-related sediment transport and Azorella cushions acting as sediment obstructions. Understanding these interactions between Azorella cushions and the landscape is especially important in the light of recent warming and drying on the island, as particle size affects soil properties such as water-holding capacity and frost susceptibility.

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Interspecific facilitation mediates the outcome of intraspecific interactions across an elevational gradient

Raath‐Krüger

Schöb²,

McGeoch

et al. 2020

Ecology

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Where interspecific facilitation favors the establishment of high densities of a beneficiary species, strong intraspecific competition may subsequently impede beneficiary performance. Consequently, the negative influence of intraspecific competition between beneficiary individuals could potentially outweigh the positive influence of interspecific facilitation when, for example, higher densities of a beneficiary are negated by the negative effect of crowding on beneficiary reproduction. The aim of this study was, therefore, to examine the impact of an interspecific interaction on the outcome of intraspecific interactions within the context of plant–plant facilitation. We used the cushion‐forming Azorella selago and a commonly co‐occurring dominant perennial grass species, Agrostis magellanica, on sub‐Antarctic Marion Island as a model system. We assessed the impact of an interspecific interaction (between A. selago and A. magellanica) on the outcome of intraspecific interactions (between A. magellanica individuals), by testing if the impact of A. magellanica density on A. magellanica performance is mediated by its interaction with A. selago. We observed evidence for competition among A. magellanica conspecifics, with a decreasing proportion of A. magellanica individuals being reproductive under higher conspecific density. This negative intraspecific effect was greater on A. selago than on the adjacent substrate, suggesting that the facilitative effect of A. selago changes the intensity of intraspecific interactions between A. magellanica individuals. However, experimentally reducing A. magellanica density did not affect the species’ performance. We also observed that the effect of A. selago on A. magellanica was positive, and despite the negative effect of intraspecific density on the proportion of reproductive A. magellanica individuals, the net reproductive effort of A. magellanica (i.e., the density of reproductive individuals) was significantly greater on A. selago than on the adjacent substrate. These results highlight that, in abiotically severe environments, the positive effects of interspecific facilitation by a benefactor species may outweigh the negative effects of intraspecific competition among beneficiaries. More broadly, these results suggest that both positive inter‐ and intraspecific biotic interactions may be key to consider when examining spatial and temporal variation in species’ performance.

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The maritime Subantarctic: a distinct periglacial environment

Cited by 78 publications

References 24 publications

Climate variations in a high altitude Alpine basin and their effects on a glacial environment (Italian Western Alps)

Climate variations in a high altitude Alpine basin and their effects on a glacial environment (Italian Western Alps)

Interactions between a cushion plant (Azorella selago) and surface sediment transport on sub-Antarctic Marion Island

Interspecific facilitation mediates the outcome of intraspecific interactions across an elevational gradient

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