Very-broad-scale assessment of human impacts on river condition

1. Management of whole rivers and river catchments requires a comprehensive set of information about river condition and use, both existing and historical, and the links between them at regional, state or national scales. This paper outlines a new approach to the assessment of river condition, using a small team was able to assess 210 000 km of rivers across more than 3 million km² of Australia in little more than a year. 2. The approach was driven by a hierarchical model of river function, which assumed that broad‐scale catchment characteristics affect local hydrology, habitat features, water quality and, ultimately, aquatic biota. The model provided the basis for selecting important ecologically relevant features that indices should represent. For each reach of each river we derived a biological index and an environmental index based on measures quantifying catchment and hydrological condition, and habitat and water quality condition. Data came from existing state and national databases, satellite images, site measurements and process models. 3. All indices were calculated as deviation from a reference condition, were range‐standardised and were divided into equivalent bands of condition. Amalgamation of index components and of sub‐indices was determined by consideration of their ecological effects; for example, general degradation might be additive, but toxic effects of one component would override all others. 4. Several internal and external validation methods were employed, with the all‐important validation of the final assessments undertaken by comparison with a similar index based on locally measured data. 5. The environmental assessment classified 14% of reaches as largely unmodified, 67% as moderately modified and 19% as substantially modified by human impacts. The biological assessment based on site assessments and modelled data using invertebrates indicated that 70% of reaches were equivalent to reference condition and that 30% were significantly impaired. Catchment disturbance, elevated sediment and nutrient loads, and habitat degradation all contributed to these results. These impacts have all occurred during the last 200 years (post‐European settlement). 6. Partly as a result of the assessments of this study the Australian Government has begun to adopt a more environmentally sustainable approach to broad‐scale water management.     

Natural Human Antibodies to “Hidden” Membrane Components

MECHANISMS of immune surveillance against altered or malignant transformed cells depend on the specific recognition of some “self-tissue” and not others. One mechanism proposed for this recognition specificity is the presence of “hidden” determinants on all cells that become exposed only when the cell undergoes specific membrane changes. In experimental support of this “hidden-site” hypothesis in the human, we here describe the presence of naturally occurring serum substances, probably IgM antibodies, found in normal humans that can lyse autologous human cells after the removal of cell surface sialic acid by neuraminidase (NASE). This represents another example of the modulation of cell surface antigenicity by NASE¹.     

Successful retrieval of mRNA from hair follicles stored at room temperature: implications for studying gene expression in wild mammals

We evaluated some products and protocols designed for reliable RNA extraction from minute tissue samples and safe tissue storage at room temperature without RNA degradation. Success of RNA retrieval was compared for varying amounts of tissue (3, 5, 10 hair follicles), stored at different temperatures (room temperature, ?20 °C) for variable durations (1, 3, 6, 12 weeks). We also compared two RNA isolation kits specialized for small samples. RNA was successfully retrieved from as few as 3 hairs stored at room temperature for up to 6 weeks, suggesting the potential for gene expression analyses on minimally invasive samples from natural populations.     

Reconstructing a complex early Neoproterozoic eukaryote, Wynniatt Formation, arctic Canada

Flanged filamentous microfossils from two geographically separated assemblages in the early Neoproterozoic Wynniatt Formation, arctic Canada, co-occur with flanged Clavitrichoides -type filaments, flanged Osculosphaera-type vesicles and wrinkled, bi-layered vesicles assigned to a new acritarch form-taxon Plicatosphaeridium impostor n. gen., n. sp. Marked similarities in morphological and microstructural detail identify most, if not all, of these forms as components of a single, relatively complex, multicellular eukaryote, Cheilofilum hysteriopsis n. gen., n. sp. The filamentous, occasionally branched thallus was composed of large cylindrical cells, and extended via rupture of cell termini. Filaments originated from Clavitrichoides -type or Osculosphaera -type vesicles via a similar process of rupture, flange formation and apical extension. Presence of a distinctively mottled wall texture supports the ontogenetic relationship of Wynniatt Cheilofilum, 'Clavitrichoides' and 'Osculosphaera,' and provides circumstantial evidence for including a Plicatosphaeridium phase. Despite superficial similarities, Cheilofilum cannot be interpreted as a filamentous cyanobacterium, strobilating scyphozoan or polychaete worm tube. The distinctive cytokinesis of the filamentous component has close analogues among the annellophores and/or phialides (conidiophores) of various hyphomycetous fungi, though its large size and absence of an associated mycelium argue against its placement within the Fungi. Unambiguous fungal synapomorphies are expressed in co-occurring Tappania, however, and both Cheilofilum and Tappania include a closely comparable Clavitrichoides -type phase in their life cycle.     

Seasonal controls on interannual variability in carbon dioxide exchange of a near-end-of rotation Douglas-fir stand in the Pacific Northwest, 1997–2006

This study analyzes 9 years of eddy‐covariance (EC) data carried out in a Pacific Northwest Douglas‐fir (Pseudotsuga menzesii) forest (58‐year old in 2007) on the east coast of Vancouver Island, Canada, and characterizes the seasonal and interannual variability in net ecosystem productivity (NEP), gross primary productivity (GPP), and ecosystem respiration (R_e) and primary climatic controls on these fluxes. The annual values (± SD) of NEP, GPP and R_e were 357 ± 51, 2124 ± 125, and 1767 ± 146 g C m^?2 yr^?1, respectively, with ranges of 267–410, 1592–2338, and 1642–2071 g C m^?2 yr^?1, respectively. Spring to early summer (March–June) accounted for more than 80% of annual NEP while late spring to early autumn (May–August) was mainly responsible for its interannual variability (～80%). The major drivers of interannual variability in annual carbon (C) fluxes were annual and spring mean air temperatures (T_a) and water deficiency during late summer and autumn (July–October) when this Douglas‐fir forest growth was often water‐limited. Photosynthetically active radiation (Q), and the combination of Q and soil water content (θ) explained 85% and 91% of the variance of monthly GPP, respectively; and 91% and 96% of the variance of monthly R_e was explained by T_a and the combination of T_a and θ, respectively. Annual net C sequestration was high during optimally warm and normal precipitation years, but low in unusually warm or severely dry years. Excluding 1998 and 1999, the 2 years strongly affected by an El Niño/La Niña cycle, annual NEP significantly decreased with increasing annual mean T_a. Annual NEP will likely decrease whereas both annual GPP and R_e will likely increase if the future climate at the site follows a trend similar to that of the past 40 years.     

Eucalyptus leachate inhibits reproduction in a freshwater fish

1. Dissolved organic carbon (DOC) can induce lethal and sub‐lethal effects in exposed biota via hypoxic blackwater events and the toxicity of leached compounds. Little is known of how DOC exposure affects fish reproduction despite the fact that its release can coincide with spawning‐associated flow pulses. 2. River red gum (Eucalyptus camaldulensis) leaf leachate is a major source of DOC in Australian freshwaters and includes the toxic plant secondary metabolites polyphenols and tannins. High concentrations of leachate are released when leaves on floodplains or dry stream channels are inundated by water. 3. Southern pygmy perch (Nannoperca australis) from naturally high and naturally low Eucalyptus leachate environments in south‐east Australia were exposed to elevated leachate levels to investigate the effects of DOC on reproduction and to explore whether response patterns were consistent with populations becoming locally adapted to historical leachate levels. 4. Fish exposed to leachate were half as likely to reach sexual maturity as control fish. Fish from a naturally high‐exposure population tended to reach sexual maturity earlier than those from a naturally low‐exposure population. Leachate exposure had no effect on either egg size or fecundity. 5. Our results suggest that leachate‐exposed mothers did not reproduce because they were physiologically stressed or perceive the environment to be unsuitable, which raises the potential of plastic or adaptive responses to this stressor. The negative sub‐lethal effects observed have important fitness implications for individuals, the viability of populations and the management of environmental flows and riparian zones.     

formatomatic: a program for converting diploid allelic data between common formats for population genetic analysis

There has been a great increase in both the number of population genetic analysis programs and the size of data sets being studied with them. Since the file formats required by the most popular and useful programs are variable, automated reformatting or conversion between them is desirable. formatomatic is an easy to use program that can read allelic data files in genepop , raw (csv ) or convert formats and create data files in nine formats: raw (csv ), arlequin , genepop , immanc /bayesass +, migrate , newhybrids , msvar , baps and structure . Use of formatomatic should greatly reduce time spent reformatting data sets and avoid unnecessary errors.     

Paludification and Forest Retreat in Northern Oceanic Environments

Examination of temperature variations over the past centuryfor Europe and the Arctic from northern Norway to Siberia suggeststhat variations in the North Atlantic Oscillation are associatedwith an increase in oceanicity in certain maritime regions.A southward depression of the treeline in favour of wet heaths,bogs and wetland tundra communities is also observed in northernoceanic environments. The physiological basis for this changein ecological succession from forest to bog is discussed inrelation to the long-term effects of flooding on tree survival.The heightened values currently detected in the North AtlanticOscillation Index, together with rising winter temperatures,and increased rainfall in many areas in northern Europe, presentsan increasing risk of paludification with adverse consequencesfor forest regeneration, particularly in areas with oceanicclimates. Climatic warming in oceanic areas may increase thearea covered by bogs and, contrary to general expectations,lead to a retreat rather than an advance in the northern limitof the boreal forest. High water-table levels are not automaticallydetrimental to forest survival as can be seen in swamp, bottomlandand mangrove forests. Consequently, the inhibitory effects offlooding on tree survival and regeneration in northern regionsshould not be uncritically accepted as merely due to high waterlevels. Evidence is discussed which suggests that physiologicaland ecological factors may interact to inhibit forest regenerationin habitats where there is a risk of prolonged winter-floodingcombined with warmer winters and cool moist summers.