Anton Seimon

Microbial Community Succession in an Unvegetated, Recently Deglaciated Soil

Primary succession is a fundamental process in macroecosystems; however, if and how soil development influences microbial community structure is poorly understood. Thus, we investigated changes in the bacterial community along a chronosequence of three unvegetated, early successional soils (∼20-year age gradient) from a receding glacier in southeastern Peru using molecular phylogenetic techniques. We found that evenness, phylogenetic diversity, and the number of phylotypes were lowest in the youngest soils, increased in the intermediate aged soils, and plateaued in the oldest soils. This increase in diversity was commensurate with an increase in the number of sequences related to common soil bacteria in the older soils, including members of the divisions Acidobacteria, Bacteroidetes, and Verrucomicrobia. Sequences related to the Comamonadaceae clade of the Betaproteobacteria were dominant in the youngest soil, decreased in abundance in the intermediate age soil, and were not detected in the oldest soil. These sequences are closely related to culturable heterotrophs from rock and ice environments, suggesting that they originated from organisms living within or below the glacier. Sequences related to a variety of nitrogen (N)-fixing clades within the Cyanobacteria were abundant along the chronosequence, comprising 6–40% of phylotypes along the age gradient. Although there was no obvious change in the overall abundance of cyanobacterial sequences along the chronosequence, there was a dramatic shift in the abundance of specific cyanobacterial phylotypes, with the intermediate aged soils containing the greatest diversity of these sequences. Most soil biogeochemical characteristics showed little change along this ∼20-year soil age gradient; however, soil N pools significantly increased with soil age, perhaps as a result of the activity of the N-fixing Cyanobacteria. Our results suggest that, like macrobial communities, soil microbial communities are structured by substrate age, and that they, too, undergo predictable changes through time.

Anomalous Cloud-to-Ground Lightning in an F5-Tornado-producing Supercell Thunderstorm on 28 August 1990

An F5 tornado that devastated Plainfield, Illinois, and environs on 28 August 1990, killing 29 people, is shown to be produced by a thunderstorm characterized by highly anomalous cloud-to-ground (CG) lightning activity. Unlike typical summertime convection in which the majority of CG flashes lower negative charge to ground, the Plainfield storm produced predominantly positive-polarity CG flashes during development. Changes in storm structure revealed by radar imagery appear tied to distinct patterns in the CG flash parameters of polarity, flash frequency, first stroke peak current, flash multiplicity, and flash location relative to the parent cumulonimbus. The primary findings are 1) the anomalous predominance (91%) of positive-polarity CG flashes during development; 2) positive CG flashes anomalously occurring mainly within the region of the storms radar reflectivity core; 3) the onset of a major downburst coinciding with a sudden increase in CG flash rate, from 4 to 17 flashes min-1, and positive perce...

A Study of Cyclone Mesoscale Structure with Emphasis on a Large-Amplitude Inertia–Gravity Wave

Abstract An analysis is presented of prominent mesoscale structure in a moderately intense cyclone with emphasis on a long-lived, large-amplitude inertia–gravity wave (IGW) that moved through the northeastern United States on 4 January 1994. Available National Weather Service WSR-88D Doppler radar and wind profiler observations are employed to illustrate the rich, time-dependent, three-dimensional structure of the IGW. As the IGW amplified [peak crest-to-trough pressure falls exceeded 13 hPa (30 min)−1], it also accelerated away from the cyclone, reaching a peak forward speed of 35–40 m s−1 across eastern New England. The IGW was one of three prominent mesoscale features associated with the cyclone, the others being a weak offshore precursor warm-frontal wave and an onshore band of heavy snow (“snow bomb”) in which peak hourly snowfalls of 10–15 cm were observed. None of these three prominent mesoscale features were well forecast by existing operational prediction models, particularly with regard to preci...

A Case Study of an Unusually Intense Atmospheric Gravity Wave

Abstract A remarkable long-lived, large-amplitude gravity wave in the Carolinas and Virginia on 27 February 1984 is investigated by means of a subsynoptic-scale case study. The wave was characterized by a minor-wave of elevation followed by a sharp wave of depression with a period of 2–3 h, a horizontal wavelength of 100–150 km and surface pressure perturbation amplitudes of 3–14 mb. The wave propagated toward the east-southeast at 1 5 m s−1, accelerating to more than 20 m s−1 after it crossed the Atlantic coast. Wave passage was accompanied by gusty surface easterly winds reaching 30 m s−1 and an abrupt termination of precipitation with the rapid surface pressure fall. The synoptic criteria identified by Uccellini and Koch as common to many cases of large amplitude gravity waves were present in this case. Gravity waves were first detected across western Tennessee and northern Mississippi in a wake depression region to the rear of an advancing squall line. An amplifying wave emerged out of the wave packet...

Supercell Tornadogenesis over Complex Terrain: The Great Barrington, Massachusetts, Tornado on 29 May 1995

Abstract The process of tornadogenesis in complex terrain environments has received relatively little research attention to date. Here, an analysis is presented of a long-lived supercell that became tornadic over complex terrain in association with the Great Barrington, Massachusetts (GBR), F3 tornado of 29 May 1995. The GBR tornado left an almost continuous 50–1000-m-wide damage path that stretched for ∼50 km. The apparent rarity of significant tornadogenesis in rough terrain from a supercell well documented in operational Doppler radar motivated this case study. Doppler radar observations showed that the GBR supercell possessed a midlevel mesocyclone well prior to tornadogenesis and that the mesocyclone intensified as it crossed the eastern edge of New York’s Catskill Mountains and entered the Hudson Valley. Tornadogenesis occurred as the GBR mesocyclone crossed the Hudson Valley and ascended the highlands to the east. Subsequently, the mesocyclone weakened as it approached the Taconic Range in western ...

Current State of Conservation Knowledge on Threatened Amphibian Species in Peru

This study documents the current state of conservation knowledge on threatened amphibian species in Peru. Following the International Union for the Conservation of Nature (IUCN) classification system, we considered species in the following categories: Critically Endangered, Endangered, Vulnerable, and Near Threatened. Even though only the first three categories are regarded as threatened by IUCN, we included the fourth category to make comparisons with the list of threatened species issued by the Peruvian government. We used the Global Amphibian Assessments database and the list issued in Peru for this comparison. We conducted separate field surveys in 17 regions of Peru to evaluate the presence/absence of threatened amphibian species and species that are potentially threatened. We also used the Declining Amphibian Database-DAPTF, to compare our results with previous assessments on population declines, and the World Wildlife Funds Wildfinder database, to determine in which Neotropical ecoregion each species occurs. We compiled data on 83 species, 44 of which are recognized as threatened by the IUCN and/or the Peruvian government. The remaining 39 species should be re-assessed as they face various threats. A re-evaluation of current estimates is needed as only 8% of all species recorded in Peru are recognized as threatened by the government, whereas the global estimate of threatened species is about 32%. In addition to using IUCN criteria, this re-assessment should follow national guidelines standardized in Peru and be in accordance with the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Because the habitat of almost 40% of threatened species reported herein still remains unprotected, and data on chytridiomycosis and other threats are lacking for most taxa, it is crucial to develop strategies for habitat conservation and research on disease dynamics in natural populations.

Recent Observation of a Proliferation of Ranunculus trichophyllus Chaix. in High-altitude Lakes of the Mount Everest Region: Comment

The record altitudes at which organisms have been found are widely dispersed in the literature. Because of their anecdotal nature—a record altitude is often discovered by chance, rarely by specifically looking for it—such records often go unpublished, or are buried within publications dealing with wider subjects. However, the distributional limits at which organisms grow (maximum or minimum altitudes as well as other limits) are critical to our understanding of numerous basic biogeographic, ecological and physiological issues (Körner, 1999). With current awareness of global warming, records of maximum altitudes for organisms have taken on an even more pressing importance: variations in the actual maximum altitudes may indicate species responses to warming (Gottfried et al., 2002; Pauli et al., 2001; Parmesan and Yohe, 2003), and fragility of life at maximum altitudes has important management consequences (Halloy, 1989; Körner, 2000). We therefore welcome Lacoul and Freedman’s (2006) observations on Ranunculus trichophyllus at a maximum altitude of 4760 m (4750 m and 4780 m are also specified in the publication) in the Nepal Himalaya, which they quote as the highest altitude from which an aquatic angiosperm has been recorded. The authors consider this to represent a range expansion likely facilitated by climatic warming, given previous record altitudes quoted for the area of only around 4000 m. However, it is worth complementing this information. The recorded altitude is considerably lower than those routinely surpassed by several vascular plants in numerous lakes in the South American Andes from latitudes 13uS to 27uS, and probably elsewhere along the cordillera, too. A few examples from above 4800 m are given here from our own experience and the literature to place the Ranunculus trichophyllus record from Nepal in perspective. Vouchers for the species cited are at LIL herbarium, Tucumán, Argentina; LPB herbarium, La Paz, Bolivia; and CUZ herbarium, Cuzco, Perú. N Cerro Cóndor, Argentina, 5350–5400 m. On the border between Tucumán and Catamarca province, this lake harbors a dense population of Zanichellia sp. despite being partly ice covered, even in mid-summer (Halloy, 1981, 1983; Kühn and Rohmeder, 1943). As far as we are aware, this is the highest published record for an aquatic vascular plant. N Lago Sibinacocha, Perú, 4880 m. This large high-altitude lake harbors diverse submerged communities, including Potamogeton, Myriophyllum, Isoëtes, and Nitella (an algae but with an almost vascular plant-like life form). Being largely unexplored, it is likely to harbor a number of other species known from lower lakes such as Titicaca. Upward range expansion in this area is being documented for diverse organisms from amphibians to plants (Halloy et al., 2005; Seimon et al., 2007). N High Andean pools and tarns often linked to peat bogs harbor a variety of submerged vascular plants, e.g. Callitriche (4800 m, Sajama, Bolivia), Myriophyllum cf. elatinoides (4600–5244 m), Potamotegon cf. pectinatus (4600–5244 m), and Isoëtes spp. (4400–5030 m); the latter three are in the Sibinacocha lake region, Perú. A large number of semi-aquatic vascular plants also characterize these communities (Carex spp., Distichia muscoides, Oxychloe andina, and many more) throughout the Andes, often reaching well above 5200 m. Previously recognized altitudinal limits for other organisms (e.g. clams, amphibians) are also being breached in the Sibinacocha area (Krajick and Peter, 2006; Seimon et al., 2007).

Planning for Species Conservation in a Time of Climate Change

The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (2007) presented clear evidence that the global climate is changing because of human activities (Box 1). There is little doubt that this human-forced climate change event will become one of the main contributors to the global loss of biological diversity and has already caused accelerated rates of species’ extinctions and changes to ecosystems across Earth (Sala et al., 2000; Thomas et al., 2004; Pimm, 2008). However, despite grim, almost doomsday-like, warnings in both the scientific literature and the general media for the best part of the last two decades (Peters & Darling 1985; Hannah et al., 2002), there has been little headway in the development of appropriate methodologies for integrating climate adaptation into conservation planning (Hannah et al., 2010; Poinani et al., 2011). The purpose of this book chapter is to describe and classify some of the different methodologies governments and non-government organisations are using to integrate climate adaptation into conservation planning. By writing this book chapter, we hope to describe some of the benefits and limitations of the different adaptation planning approaches that are currently being espoused in the conservation arena. We conclude by describing some of the major hurdles human-forced climate change presents to conservation planners and some ways to overcome these. By no means is this an exhaustive review; rather, it builds on the work of others (e.g. Mawdsley et al., 2009; Dawson et al., 2011) by categorising some of the different adaptation planning activities being conducted within the conservation realm, so as to provide some clarity to national and international policy makers, private and public funding agencies, and practitioners, on what the best options are for conservation planning when climate change is considered. Here, we focus on species-oriented conservation planning because it will ultimately be the reaction of species that define how ecosystems (and the services they provide) change because of human-forced climate change; species, as the basic evolutionary unit always need to be a focus of conservation planning. Although this chapter is species focused, many of the

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.

Assessing the Threat of Amphibian Chytrid Fungus in the Albertine Rift: Past, Present and Future

Batrachochytrium dendrobatidis (Bd), the cause of chytridiomycosis, is a pathogenic fungus that is found worldwide and is a major contributor to amphibian declines and extinctions. We report results of a comprehensive effort to assess the distribution and threat of Bd in one of the Earth’s most important biodiversity hotspots, the Albertine Rift in central Africa. In herpetological surveys conducted between 2010 and 2014, 1018 skin swabs from 17 amphibian genera in 39 sites across the Albertine Rift were tested for Bd by PCR. Overall, 19.5% of amphibians tested positive from all sites combined. Skin tissue samples from 163 amphibians were examined histologically; of these two had superficial epidermal intracorneal fungal colonization and lesions consistent with the disease chytridiomycosis. One amphibian was found dead during the surveys, and all others encountered appeared healthy. We found no evidence for Bd-induced mortality events, a finding consistent with other studies. To gain a historical perspective about Bd in the Albertine Rift, skin swabs from 232 museum-archived amphibians collected as voucher specimens from 1925–1994 were tested for Bd. Of these, one sample was positive; an Itombwe River frog (Phrynobatrachus asper) collected in 1950 in the Itombwe highlands. This finding represents the earliest record of Bd in the Democratic Republic of Congo. We modeled the distribution of Bd in the Albertine Rift using MaxEnt software, and trained our model for improved predictability. Our model predicts that Bd is currently widespread across the Albertine Rift, with moderate habitat suitability extending into the lowlands. Under climatic modeling scenarios our model predicts that optimal habitat suitability of Bd will decrease causing a major range contraction of the fungus by 2080. Our baseline data and modeling predictions are important for comparative studies, especially if significant changes in amphibian health status or climactic conditions are encountered in the future.