Climatic significance of intra-annual bands in the wood of <Emphasis Type="Italic">Nothofagus pumilio</Emphasis> in southern Patagonia

Nothofagus pumilio (Poepp et Endl.) Krasser is the dominant subalpine tree in the southern Andes between 36°S and 55°S. Increment cores from a N. pumilio stand growing near the Ameghino Glacier (50°25S, 73°10W), southern Patagonian Andes, Argentina, contain significant numbers of intra-annual bands (or false rings) which have not been previously described for this species. These samples are used to develop a well-replicated ring-width chronology and a record of intra-annual bands from AD 1760 to 1997. Annual variations in radial growth of N. pumilio at this site are negatively correlated with spring–summer temperatures and positively with spring precipitation. The formation of intra-annual bands appears to be a response to anomalously dry-warm springs followed by wet-warm late summers. Intra-annual bands may occur in up to 95% of the sampled trees in a given year, and the percentage of trees affected was used as an indication of the strength of the forcing event. Narrow rings occurred in the years following intra-annual band formation, reflecting the lagged effect of unfavorable climatic conditions on tree growth during the subsequent growing season. Intra-annual bands occurred more frequently in the twentieth century than the late eighteenth and nineteenth centuries. This contrasting pattern seems to be a response to the combination of a long-term warming trend and a significant decrease in precipitation recorded during the last 100 years in this region of southern South America.

A single operon-encoded form of the acetyl-CoA decarbonylase/synthase multienzyme complex responsible for synthesis and cleavage of acetyl-CoA in <Emphasis Type="Italic">Methanosarcina thermophila</Emphasis>

Methanogens growing on C-1 substrates synthesize 2-carbon acetyl groups in the form of acetyl-CoA for carbon assimilation using the multienzyme complex acetyl-CoA decarbonylase/synthase (ACDS) which contains five different subunits encoded within an operon. In species growing on acetate ACDS also functions to cleave the acetate C-C bond for energy production by methanogenesis. A number of species of Methanosarcina that are capable of growth on either C-1 compounds or acetate contain two separate ACDS operons, and questions have been raised about whether or not these operons play separate roles in acetate synthesis and cleavage. Methanosarcina thermophila genomic DNA was analyzed for the presence of two ACDS operons by PCR amplifications with different primer pairs, restriction enzyme analyses, DNA sequencing and Southern blot analyses. A single ACDS operon was identified and characterized, with no evidence for more than one. MALDI mass spectrometric analyses were carried out on ACDS preparations from methanol- and acetate-grown cells. Peptide fragmentation patterns showed that the same ACDS subunits were present regardless of growth conditions. The evidence indicates that a single form of ACDS is used both for acetate cleavage during growth on acetate and for acetate synthesis during growth on C-1 substrates. Electronic Supplementary Material  Supplementary material is available for this article at

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Effect of ecological factors on intra-annual stem girth increment of holm oak

Key message

The intra-annual stem girth increment of Quercus ilex is mainly driven by water availability and secondly by temperature. Tree size and competition modulate the growth response to climate.

Abstract

Holm oak (Quercus ilex ssp. ballota [Desf.] Samp.) is the most widespread species in the Iberian peninsula, being one of the most representative trees in forests and open woodlands. The analysis of stem girth increment of holm oak may provide valuable information about how Mediterranean ecosystems will respond to the forecasted climate changes. However, due to the variability of the Mediterranean climate, the knowledge of intra-annual patterns of growth is needed for a better understanding of the influence of the climatic variables at this scale. To this end, we used band dendrometers to measure monthly stem girth increments of 96 holm oak trees from 2003 to 2010, located in open woodlands and dense Mediterranean forests in southwestern Spain. We assessed the effects of climate, competition, topography, and initial stem diameter on stem girth increment. The major stem increment periods were in spring and autumn whereas increment rates were very low or even negative in winter and summer. Spring was not every year the season with the higher stem increments, but autumn when spring was very dry. Higher precipitation, soil moisture, and relative humidity had significant positive effects on stem increment, whereas higher temperature, reference evapotranspiration, and solar radiation had significant negative effects. Initial tree diameter and competition from nearby trees partly explained significant differences in stem increment of individual trees. Therefore, the forecasted climatic changes, in which decreased rainfall in spring and increased summer drought are expected in the Mediterranean region, may be a significant threat to the Q. ilex ecosystems.     

A Faithful Record of Stressful Life Events Recorded in the Dental Developmental Record of a Juvenile Gorilla

The pattern and rate of dental development are critical components of the life history of primates. Much recent research has focused on dental development in chimpanzees and other hominoids, but comparatively little is known about dental development in Gorilla. To date, dental chronologies for Gorilla are based on a sample of 1 and information about variations in the time and timing of crown initiation and completion is lacking. We provide data on dental development in 1 captive, juvenile, female, western lowland Gorilla gorilla gorilla of known age, sex, life events, and date of death (carefully documented as part of zoo records) that experienced various physical insults during her first year of life. The perfect natural experiment allowed us to test the association of the timing of accentuated stress lines in teeth with significant physiological and psychological events during ontogeny of this juvenile gorilla. We analyzed histological sections from 14 permanent teeth (maxillary and mandibular I1-M2) and assessed crown initiation (CI) and crown formation times (CFT) using short- and long-period incremental lines in both enamel and dentine; they are advanced for all teeth compared to previously published chronology. The data suggest a relatively accelerated pace of dental development in gorillas compared to chimpanzees and fit an emerging pattern of an accelerated life history schedule in gorillas. Data on the timing of major accentuated lines in the developing dentition are tightly associated with exact dates of surgical procedures and follow-up hospital visits as recorded on zoo medical records. Our data highlight the importance of captive individuals with well-documented medical records for studying life history.

Distribution, Habitat Correlates, and Conservation of Loris lydekkerianus in Karnataka, India

We surveyed slender lorises (Loris lydekkerianus) in Karnataka, south India intermittently during November 2001–July 2004 and estimated their relative abundance via direct sightings. Two subspecies, Loris lydekkerianus lydekkerianus and L. l. malabaricus, with different morphological traits, occur in the eastern drier region and the western wet region of the state, respectively. The distribution of Loris lydekkerianus lydekkerianus is patchy in a small region in the southeast, which contradicts earlier reports of its abundance throughout the state. Loris lydekkerianus malabaricus occurs throughout the Western Ghats as a contiguous population. The encounter rates of Loris lydekkerianus lydekkerianus and L. l. malabaricus are 0.41 individuals/km and 0.21 individuals/km, respectively. Whereas several forest tracts in the distributional range of Loris lydekkerianus malabaricus are protected areas, no such area exists in the distributional range of L. l. lydekkerianus. Loris lydekkerianus faces serious challenges of conservation because it largely occurs in commercial plantations, which can be relatively unstable habitats as harvesting can take place at any time.

Influence of groundwater on the evaporative evolution of saline lakes in the Wimmera of south-eastern Australia

A hydrogeochemical study conducted in the southern Wimmera of western Victoria, south-eastern Australia reveals a small group of lakes that possess a range of chemical character so diverse that it compares to that recorded for lakes from the entire region of western Victoria and south-eastern South Australia. Principal Components Analysis and reaction path modelling using PHRQPITZ confirm that the chemical diversity of the lakes is largely inherited from the groundwater system. Three end-members (in the Eugster–Jones–Hardie framework) were identified: (i) Path 1B groundwaters transmitted via the fractures of a sandstone monolith; (ii) Path 2A-1A groundwaters derived, in part, from a limestone aquifer; and (iii) groundwaters that carry an essentially meteoric, Path 2A signature. The relative contribution of these path 1B and/or path 2A end-members largely determines the evaporative pathway (1B or 2A) that is subsequently followed, and creates a broad spread in the data. Sulphate reduction, ion exchange, silicate hydrolysis and carbonate mineral solubility also play important roles locally, in some cases displacing lake waters from one evaporation field to another. The chemical processes identified likely contribute to aquatic biodiversity in the region, due to the strong control on the ionic composition of the lakes.

Review of dated Late Quaternary palaeolimnological records in the Carpathian Region,east-central Europe

The Carpathian Region (including mountains and plains) has for a long time been lacking good palaeoenvironmental and especially palaeolimnological records, particularly for the Late Quaternary. In the last two decades, many new sedimentary sequences were obtained and studied using a wide range of palaeoproxies. This article reviews results from 123 sequences in the Carpathian Region, all dated by radiometric methods. Our aim was to pay attention to the existence of these data; many of them published in national periodicals and journals. Palaeoenvironmental records with at least two proxies and with palaeolimnological interpretation were compiled in both tabular form and on maps. Inspite of the density of examined sites, an assessment of the dataset led us to the following conclusions: (1) very few provide firm hydrological–limnological interpretation, such as lake level and mire water-depth fluctuation, lake productivity changes and pH changes; (2) only 47 of them are real multi-proxy studies (have at least two proxies employed on the same sediment core); (3) glacial lakes in Slovakia and Romania as well as in Ukraine are seriously under-investigated although they would be ideal objects of palaeolimnological works with the many proxies applicable on them; (4) the Hungarian lowland areas are dominated by shallow tectonic lakes or palaeochannels, often with unsatisfactory preservation of certain biological proxies (e.g. diatoms, chironomids, cladocerans). Consequently, palaeolimnological studies from this region have to apply a different combination of proxies and approach than mountain lake studies.

Rattus exulans and the catastrophic disappearance of Hawai’i’s native lowland forest

Paleoenvironmental and archaeological investigations from the ’Ewa Plain of O’ahu provide insight into the problem of understanding lowland native forest loss in Hawai’i. Data from pollen analysis of a pond core record, avian paleontology, and archeology, document a precipitous decline of the native forest starting before Polynesian settlement on the ’Ewa Plain but after Polynesian colonization of O’ahu. It is hypothesized that rats, introduced by Polynesian colonizers, increased exponentially in the absence of significant predators or competitors, feeding on a largely endemic vegetation that had evolved in the absence of mammalian predators. Rats radiated ahead of human colonizers on O’ahu, eating their way through the vegetation, perhaps before the colonizers had encountered much of the pristine lowland forest into which the rats had radiated. This hypothesis is supported by several observations, including the almost complete absence of extinct or extirpated avian faunal remains in archaeological deposits, the present distribution of endemic vegetation in Hawai’i, rat ecology, population biology, and other evidence.

Skunkworks in the Embers of the Cedar Fire: Enhancing Resilience in the Aftermath of Disaster

A coalition of environmental activists and professionals created the San Diego Fire Recovery Network (SDFRN) while the largest wildfire in California history was still burning at the city’s edge in October 2003. Acting quickly while the citizenry questioned governmental ability to protect their rapidly growing region, SDFRN proposed to reduce fire risk in a way that altered residential knowledge practices and identity while reshaping governance relationships. While this effort stalled after governmental agencies restored public confidence through massive fire prevention initiatives, SDFRN’s efforts may not have been in vain. Retained within collective memory, SDFRN contributed to community resilience by diversifying possible responses to environmental change and uncertainty. In this way, flexible, informal learning organizations such as SDFRN may serve as “skunkworks,” seizing on disaster in order to incubate social–ecological relationships that might avert greater tragedies to come.

Differences in daily stem size variation and growth in two hybrid eucalypt clones

Understanding daily stem size variation is important as the net increment of a forest stand is ultimately determined by the accumulation of daily increment events. In this study, measurements of stem size at high spatial and temporal resolution were made using two commercial hybrid Eucalyptus clones [E. grandis × urophylla (GU) and E. grandis × camaldulensis (GC)] over a period of more than 3.5 years in order to better understand how daily stem growth is effected by variations in environmental conditions. It was evident that GU had fewer days on which net growth occurred than GC. However, when growth did occur, GU grew for longer each day and at a higher rate than GC. Thus, it still had an overall larger net stem increment during the study period. The GU clone had a markedly intermittent pattern of growth, such that growth essentially ceased under drought conditions, but responded rapidly when water became available. This confirms other findings that E. grandis × urophylla is more susceptible to drought stress than E. grandis × camaldulensis, but emphasizes that a strategy of “rapid response” when environmental conditions become temporarily non-limiting is a good one in terms of net increment at sites such as in this study.

Dendrochronology of Norway spruce (Picea abies (L.) Karst.) from two range centres in lowland Poland

In Europe, spruce grows in two main regions which meet in Poland, one to the north and east, the other to the south and west. The northeastern area ranges from the northern treeline extending from Norway to Siberia, to southern Sweden, north-eastern Poland and the southern Ural mountains. The southwestern spruce region reaches the mountainous areas of the Alps and the Balkans, the mountains and uplands of the Sudety Mountains, the Carpathians and neighbouring lowlands. Opinions about the distribution of Norway spruce have changed over the years, and its scarcity in the centre of Poland has been strongly debated. The favoured current theory is that Norway spruce once had a continuous distribution in Poland. It is assumed that the rare occurrence in the central Polish lowland is due to a combination of unfavourable soil conditions and previous management activity. The main aim of this work was to analyse climate–growth relationships of Norway spruce in eastern Poland and distinguish regions with similar increment patterns with regards to spruce range. Spruce growth in northern Polish sites is positively correlated with rainfall from May to July. Tree-ring widths in southern sites are more correlated with March temperature. Selected homogenous regions are the same as range types. Trees from the so-called “spruceless area” seem to have similar climate–growth relationships to trees from the southern region. This finding does not settle the question of the origin of the trees, but it does indicate that similar environmental conditions exist in these two areas and proves that the climate was not a limiting factor there.

Breeding in the monsoon: semi-annual reproduction in the Seychelles warbler ( Acrocephalus sechellensis )

Despite the absence of pronounced changes in day length, there is considerable climatological seasonality in the tropics. Its expression can be complex like in the monsoon climate of the Indian Ocean Islands. The land mass distribution on both sides of the equator leads to seasonal changes in prevailing wind direction and seasonal patterns in food supply, which are distinct between different coasts. Here we assess that territory quality of the Seychelles warbler, endemic to the small island of Cousin peaks during the South East monsoon (April to September) in most of the island. The Southeastern wind-exposed side is exceptional by being generally poor and having slightly increased food supply in the opposite season (NW monsoon; October to March). In response, the warblers in most territories breed primarily during the SE season, while on the SE shores they tend to breed in both seasons. The result is a semi-annual periodicity in breeding. Individual pairs can breed in 6 months intervals. In the poorer territories on the SE shore most of them indeed do this, while in the richer central habitats most pairs restrict themselves to the best (SE) season. The frequency of breeding thereby increases with territory quality in the SE season, and decreases with quality in the NW season. Withholding from breeding in the NW season despite the high food supply may have long-term advantages for the birds occupying the richer habitat. Such flexible adjustment of seasonality to local circumstances requires not only an immediate response mechanism but also access to accurate information about time of year. The subtle sensitivity of tropical songbirds to photoperiod, demonstrated so convincingly by Eberhard Gwinner (Biological rhythms, Hokkaido University Press, Sapporo, pp19–40, 2005), may well have profound adaptive meaning in taking temporally optimized reproductive decisions in response to both food and time of year.

Unmonitored trade in marine ornamental fishes: the case of Indonesia’s Banggai cardinalfish (<Emphasis Type="Italic">Pterapogon kauderni</Emphasis>)

Millions of coral reef fishes are collected each year for sale on the international aquarium market. Several marine ornamental species, including the Banggai cardinalfish, are biologically unsuitable for large-scale exploitation, yet their trade continues largely unmonitored. With little known about the Banggai cardinalfish or its trade, we interviewed trade participants from north and central Sulawesi, Indonesia, to document the organization, scale, and price structure of the species local collection and sale. Interviews revealed a large and growing commerce in Banggai cardinalfish, with at least 118,000 fish per month being sold in the Banggai region during the study period. Given the scale of the trade, the species restricted geographic range, and its natural susceptibility to exploitation, we propose that long-term monitoring is needed to safeguard Banggai cardinalfish populations and to serve as a much-needed example for monitoring and managing other marine ornamental fishes at risk of over-exploitation.

The number of days on which increment occurs is the primary determinant of annual ring width in Callitris intratropica

Key message

The number of days on which a measureable increment occurred, and the average rate of stem growth, rather than the overall duration of the wet season, were the main determinants of ring width in young Callitris intratropica trees. These effects were amplified by competition.

Abstract

Dendroclimatology of tropical tree species is an important tool for understanding past climatic variability at low latitudes where long-term weather records are often absent. Despite the growing number of published tropical tree-ring chronologies, however, still little is known of the factors that control annual ring formation in tropical tree species. In this paper we used an endemic Australian conifer, Callitris intratropica, to study the intra-annual dynamics of seasonal growth and xylem formation, and the effects of environmental conditions and competition, on growth ring formation. We combined high-resolution growth and climate monitoring (every 15 min for 2 years) with less frequent cambial sampling. Trees exhibited marked reductions in growth during certain periods within the rainy season when rainfall was not as regular and VPD was high. Overall, we found that ring width was most influenced by the number of days when increment occurred; regardless of how early the growing season began or ended, and by the rates of tracheid production. The effect of competition was also important. Trees growing in dense groves had narrower annual rings (4.6 mm) than trees that were growing in the open (6.7 mm), due to less active cambia, slower rates of xylem production and expansion and more increment days, although the overall growing season duration was also shorter in grove trees.     

Changing Access to Labor,Pastures, and Knowledge: The Extensification of Grazing Management in Sudano-Sahelian West Africa

The broader ecological and social contexts within which livestock husbandry of Sudano-Sahelian West Africa operates have changed significantly over the past thirty years. This study concerns how: (1) these broader trends have affected the quantity and quality of labor investments into livestock herding; and (2) the ecological and animal nutritional implications of observed variation in labor investments into herding. The study was conducted in a 500 km² area of western Niger using a combination of qualitative interviews of herders and herd managers, household composition surveys, herd composition monitoring, grazing management monitoring and georeferenced vegetation and livestock grazing itinerary data. Statistical analyses were performed using a two-staged approach: (1) analysis of the factors affecting the allocation of labor to herding at the level of the managing household; and (2) analysis of the effect of herd characteristics, season, microgeography and herders’ social position on herders’ effort and the nutritional and ecological impacts of these efforts. The results of these analyses support the conclusion that the changing regional context of livestock husbandry leads to a reduction in labor (quantity and quality) investment or an “extensification” of herding with significant implications for livestock productivity and the environment.

Two new species of <Emphasis Type="Italic">Mycena</Emphasis> from alpine sites in Norway

Mycena aphanes and Mycena exilis, belonging to section Filipedes and section Polyadelphia, are proposed as new species. They are described and illustrated and compared to other species in the two sections. Mycena aphanes is a strikingly characteristic Mycena with fulvous or yellowish brown colours of both pileus and stipe. Mycena exilis is characterized by its occurrence on fallen Salix leaves, a pale brown pileus, occasionally with a pale pink tinge, narrowly adnate lamellae, four-spored basidia, and the presence of clamp connections.

Novae Gesneriaceae Neotropicarum IV: Alloplectus purpureus and Columnea nematoloba—New Gesneriaceae from northwestern South America

Two species of Gesneriaceae are described:Alloplectus purpureus from the lower montane forests of northwestern Ecuador and adjacent Colombia andColumnea nematoloba from the lowland rain forests of western Colombia. The first with its fimbriate calyx lobes is probably nearest toAlloplectus sprucei, occurring in the same region but mostly at lower elevations. The second is in a group with two recently described species from western Ecuador and Colombia,Columnea fililoba andC. incredibilis, all having filiform corolla lobes.     

Prediction of the doubly charged ion pattern by modelling the high- and low-resolution mass spectra of isotopomeric forms

The presence of doubly charged ions in mass spectra is detected only occasionally because their clusters are observed more rarely than singly charged ones. The patterns connected with doubly charged ions are located in the spectrum below M/2. The narrow shapes of such patterns as well as overlapping with other bands generate significant problems in their interpretation. The method described here is based on modelling of the isotopomeric form of single- and double-charged mass ion clusters. The present work attempts to explain the generation of the double charge disotopomeric patterns of high- as well as low-resolution spectra. Predicting the high-resolution mass cluster is simpler than calculations of the low-resolution cluster. The high-resolution cluster may represent the initial form of low-resolution pattern formation.