Stephan Halloy

Fumarole-Supported Islands of Biodiversity within a Hyperarid, High-Elevation Landscape on Socompa Volcano, Puna de Atacama, Andes†

ABSTRACT Fumarolic activity supports the growth of mat-like photoautotrophic communities near the summit (at 6,051 m) of Socompa Volcano in the arid core of the Andes mountains. These communities are isolated within a barren, high-elevation landscape where sparse vascular plants extend to only 4,600 m. Here, we combine biogeochemical and molecular-phylogenetic approaches to characterize the bacterial and eucaryotic assemblages associated with fumarolic and nonfumarolic grounds on Socompa. Small-subunit rRNA genes were PCR amplified, cloned, and sequenced from two fumarolic soil samples and two reference soil samples, including the volcanic debris that covers most of the mountain. The nonfumarolic, dry, volcanic soil was similar in nutrient status to the most extreme Antarctic Dry Valley or Atacama Desert soils, hosted relatively limited microbial communities dominated by Actinobacteria and Fungi, and contained no photoautotrophs. In contrast, modest fumarolic inputs were associated with elevated soil moisture and nutrient levels, the presence of chlorophyll a, and 13C-rich soil organic carbon. Moreover, this soil hosted diverse photoautotroph-dominated assemblages that contained novel lineages and exhibited structure and composition comparable to those of a wetland near the base of Socompa (3,661-m elevation). Fumarole-associated eucaryotes were particularly diverse, with an abundance of green algal lineages and a novel clade of microarthropods. Our data suggest that volcanic degassing of water and 13C-rich CO2 sustains fumarole-associated primary producers, leading to a complex microbial ecosystem within this otherwise barren landscape. Finally, we found that human activities have likely impacted the fumarolic soils and that fumarole-supported photoautotrophic communities may be exceptionally sensitive to anthropogenic disturbance.

Climate-Change Effects on Alpine Plant Biodiversity: A New Zealand Perspective on Quantifying the Threat

Abstract New Zealands alpine region is populated by many (∼613) species of vascular plants with a high endemism (∼93%). To investigate the potential impact of climate warming, we used species-area relations to estimate current and projected vascular plant floras and tested model sensitivity scaling from the whole world to small alpine regions. Within their limitations, these models show that if the present mean temperature of ∼0.6°C higher than in 1900 were maintained, together with a large pool of exotic species, 40–70 species of native plants could become at risk. With a rise of 3°C, an approximate expectation for the following 100 yr, the total New Zealand alpine vascular flora could reach ∼550–685 species and lose 200–300 indigenous alpine species, the rest being exotic. Fragmentation of alpine areas could, over millennia, favor speciation, but in the short term, the loss of ∼80% of existing alpine islands will severely increase extinction risks. These model projections will be modified by downward extension of species through unplanned vegetation destruction, or following deliberate vegetation clearance to create habitats favorable to alpine species, as well as through a number of other as yet unquantified factors. These projections are not predictions of extinctions but rather broad probabilities of risk to a whole flora.

Will loss of snow cover during climatic warming expose New Zealand alpine plants to increased frost damage

If snow cover in alpine environments were reduced through climatic warming, plants that are normally protected by snow-lie in winter would become exposed to greater extremes of temperature and solar radiation. We examined the annual course of frost resistance of species of native alpine plants from southern New Zealand that are normally buried in snowbanks over winter (Celmisia haastii and Celmisia prorepens) or in sheltered areas that may accumulate snow (Hebe odora) and other species, typical of more exposed areas, that are relatively snow-free (Celmisia viscosa, Poa colensoi, Dracophyllum muscoides). The frost resistance of these principal species was in accord with habitat: those from snowbanks or sheltered areas showed the least frost resistance, whereas species from exposed areas had greater frost resistance throughout the year. P. colensoi had the greatest frost resistance (−32.5°C). All the principal species showed a rapid increase in frost resistance from summer to early winter (February–June) and maximum frost resistance in winter (July–August). The loss of resistance in late winter to early summer (August–December) was most rapid in P. colensoi and D. muscoides. Seasonal frost resistance of the principal species was more strongly related to daylength than to temperature, although all species except C. viscosa were significantly related to temperature when the influence of daylength was accounted for. Measurements of chlorophyll fluorescence indicated that photosynthetic efficiency of the principal species declined with increasing daylength. Levels of frost resistance of the six principal alpine plant species, and others measured during the growing season, were similar to those measured in tropical alpine areas and somewhat more resistant than those recorded in alpine areas of Europe. The potential for frost damage was greatest in spring. The current relationship of frost resistance with daylength is sufficient to prevent damage at any time of year. While warmer temperatures might lower frost resistance, they would also reduce the incidence of frosts, and the incidence of frost damage is unlikely to be altered. The relationship of frost resistance with daylength and temperature potentially provides a means of predicting the responses of alpine plants in response to global warming.

Mycorrhizal and Dark-Septate Fungi in Plant Roots Above 4270 Meters Elevation in the Andes and Rocky Mountains

ABSTRACT Arbuscular mycorrhizal (AM) and dark-septate endophytic (DSE) fungi were quantified in plant roots from high-elevation sites in the Cordillera Vilcanota of the Andes (Perú) and the Front Range of the Colorado Rocky Mountains (U.S.A.). At the highest sites in the Andes (5391 m) AM fungi were absent in the two species of plants sampled (both Compositae) but roots of both were heavily colonized by DSE fungi. At slightly lower elevations (5240–5250 m) AM fungi were present in roots while DSE fungi were rare in plants outside of the composite family. At the highest sites sampled in Colorado (4300 m) AM fungi were present, but at very low levels and all plants sampled contained DSE fungi. Hyphae of coarse AM fungi decreased significantly in plant roots at higher altitude in Colorado, but no other structures showed significant decreases with altitude. These new findings indicate that the altitudinal distribution of mycorrhizal fungi observed for European mountains do not necessarily apply to higher and drier mountains that cover much of the Earth (e.g. the Himalaya, Hindu Kush, Andes, and Rockies) where plant growth is more limited by nutrients and water than in European mountains. This paper describes the highest altitudinal records for both AM and DSE fungi, surpassing previous reported altitudinal maxima by about 1500 meters.

When experts disagree: the need to rethink indicator selection for assessing sustainability of agriculture

Sustainability indicators are well recognized for their potential to assess and monitor sustainable development of agricultural systems. A large number of indicators are proposed in various sustainability assessment frameworks, which raises concerns regarding the validity of approaches, usefulness and trust in such frameworks. Selecting indicators requires transparent and well-defined procedures to ensure the relevance and validity of sustainability assessments. The objective of this study, therefore, was to determine whether experts agree on which criteria are most important in the selection of indicators and indicator sets for robust sustainability assessments. Two groups of experts (Temperate Agriculture Research Network and New Zealand Sustainability Dashboard) were asked to rank the relative importance of eleven criteria for selecting individual indicators and of nine criteria for balancing a collective set of indicators. Both ranking surveys reveal a startling lack of consensus amongst experts about how best to measure agricultural sustainability and call for a radical rethink about how complementary approaches to sustainability assessments are used alongside each other to ensure a plurality of views and maximum collaboration and trust amongst stakeholders. To improve the transparency, relevance and robustness of sustainable assessments, the context of the sustainability assessment, including prioritizations of selection criteria for indicator selection, must be accounted for. A collaborative design process will enhance the acceptance of diverse values and prioritizations embedded in sustainability assessments. The process by which indicators and sustainability frameworks are established may be a much more important determinant of their success than the final shape of the assessment tools. Such an emphasis on process would make assessments more transparent, transformative and enduring.

Latitudinal and altitudinal patterns of plant community diversity on mountain summits across the tropical Andes

The high tropical Andes host one of the richest alpine floras of the world, with exceptionally high levels of endemism and turnover rates. Yet, little is known about the patterns and processes that structure altitudinal and latitudinal variation in plant community diversity. Herein we present the first continental-scale comparative study of plant community diversity on summits of the tropical Andes. Data were obtained from 792 permanent vegetation plots (1m2) within 50 summits, distributed along a 4200 km transect; summit elevations ranged between 3220 and 5498 m.a.s.l. We analyzed the plant community data to assess: (1) differences in species abundance patterns in summits across the region, (2) the role of geographic distance in explaining floristic similarity, and (3) the importance of altitudinal and latitudinal environmental gradients in explaining plant community composition and richness. On the basis of species abundance patterns, our summit communities were separated into two major groups: Puna and Paramo. Floristic similarity declined with increasing geographic distance between study-sites, the correlation being stronger in the more insular Paramo than in the Puna (corresponding to higher species turnover rates within the Paramo). Ordination analysis (CCA) showed that precipitation, maximum temperature and rock cover were the strongest predictors of community similarity across all summits. Generalized Linear Model (GLM) quasi-Poisson regression indicated that across all summits species richness increased with maximum air temperature and above-ground necromass and decreased on summits where scree was the dominant substrate. Our results point to different environmental variables as key factors for explaining vertical and latitudinal species turnover and species richness patterns on high Andean summits, offering a powerful tool to detect contrasting latitudinal and altitudinal effects of climate change across the tropical Andes. This article is protected by copyright. All rights reserved.

Status of New Zealand biodiversity research and resources: How much do we know?

A survey of present genetic resources and associated research and funding was conducted in May 1992 at the request of the Ministry of Research, Science and Technology (MRST) and the Commonwealth Science Council (CSC). Abundant information was supplied by scientific institutions, government departments, botanic gardens, horticultural societies and private individuals but much of it is disconnected and difficult to compare. There are large genetic resources in New Zealand, but a shortage of information and communication about them. There are an estimated 50,000 species of native animals, plants, fungi and protists in New Zealand, of which fewer than 17,000 have been described, including only small proportions of some groups, e.g. fungi (20%) or insects (55%) but more in others, e.g. plants (more than 80%). However, we understand the numbers, population dynamics, conservation status and management requirements of only a handful of species. Fewer than 25% of the plant species are cultivated and none is econom...

Long-term monitoring of tropical alpine habitat change, Andean anurans, and chytrid fungus in the Cordillera Vilcanota, Peru: Results from a decade of study

Abstract The Cordillera Vilcanota in southern Peru is the second largest glacierized range in the tropics and home to one of the largest high‐alpine lakes, Sibinacocha (4,860 m). Here, Telmatobius marmoratus (marbled water frog), Rhinella spinulosa (Andean toad), and Pleurodema marmoratum (marbled four‐eyed frog) have expanded their range vertically within the past century to inhabit newly formed ponds created by ongoing deglaciation. These anuran populations, geographically among the highest (5,200–5,400 m) recorded globally, are being impacted by the chytrid fungus Batrachochytrium dendrobatidis (Bd), and the disease it causes, chytridiomycosis. In this study, we report results from over a decade of monitoring these three anuran species, their habitat, and Bd infection status. Our observations reveal dynamic changes in habitat including ongoing rapid deglaciation (18.4 m/year widening of a corridor between retreating glaciers from 2005 to 2015), new pond formation, changes in vegetation in amphibian habitat, and widespread occurrence of Bd in amphibians in seven sites. Three of these sites have tested positive for Bd over a 9‐ to 12‐year period. In addition, we observed a widespread reduction in T. marmoratus encounters in the Vilcanota in 2008, 2009, and 2012, while encounters increased in 2013 and 2015. Despite the rapid and dynamic changes in habitat under a warming climate, continued presence of Bd in the environment for over a decade, and a reduction in one of three anuran species, we document that these anurans continue to breed and survive in this high Andean environment. High variability in anuran encounters across sites and plasticity in these populations across habitats, sites, and years are all factors that could favor repopulation postdecline. Preserving the connectivity of wetlands in the Cordillera Vilcanota is therefore essential in ensuring that anurans continue to breed and adapt as climate change continues to reshape the environment.

Ecological responses to 52 years of experimental snow manipulation in high-alpine cushionfield, Old Man Range, south-central New Zealand

Abstract Periodic monitoring over 52 years have revealed temporal changes in the vegetation and floristic patterns associated with what has been acclaimed to be the worlds oldest known experimental snow fence, which is located on an exposed high-alpine cushionfield on the Old Man Range in south-central New Zealand. The induced pattern of intermittent snow-lie has been increased by the fence from the normal ∼140 days to more than 200 days (and 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 natural snowbanks on the range have established in areas of induced snow accumulation. The timing of species establishment was not obviously related to relevant features of the 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 and plant productivity being associated with the deepest snow in the lee of the fence. In addition, three of the several measured physical and chemical soil factors (Mg, available PO43-, and C:N) have differentiated significantly in relation to the vegetation and snow-lie 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.

A new and rare, plate-shaped Geranium from the Cumbres Calchaquíes, Tucumán, Argentina

A new species of Geranium endemic to a small (∼10 ha) area of the high Cumbres Calchaquíes, Tucumán, Argentina, is described. The species is unique within the genus in its highly condensed, plate-shaped growth form, its subterranean branching system, its thick, deep taproot, and its minute leaves with mostly 5–7 lobes. The environment is cold (∼1.5°C mean annual temperature), but equable (low diurnal fluctuations). Soils are subject to intense moisture fluctuations and freeze-thaw cycles. The total population of the species is estimated at <10,000 individuals.ResumenSe describe una nueva especie de Geranium rara y endémica de una pequeña área (∼10 ha) de las altas Cumbres Calchaquíes, Tucumán, Argentina. La especie es única dentro del género por su forma de vida altamente condensada en forma de placa, su sistema de ramificación subterráneo, su raíz pivotante gruesa y profunda, y por sus hojas diminutas, la mayoría con 5–7 lóbulos. El ambiente es frío (temperatura media annual ∼1.5°C) pero ecuable (fluctuaciones diurnas bajas), estando los suelos sujetos a intensas fluctuaciones hídricas y a solifluxión. La población total de la especie se estima en <10,000 individuos.