Impacts of forestry planting on primary production in upland lakes from north‐west Ireland

Planted forests are increasing in many upland regions worldwide, but knowledge about their potential effects on algal communities of catchment lakes is relatively unknown. Here, the effects of afforestation were investigated using palaeolimnology at six upland lake sites in the north‐west of Ireland subject to different extents of forest plantation cover (4–64% of catchment area). ²¹⁰Pb‐dated sediment cores were analysed for carotenoid pigments from algae, stable isotopes of bulk carbon (δ¹³C) and nitrogen (δ¹⁵N), and C/N ratios. In lakes with >50% of their catchment area covered by plantations, there were two‐ to sixfold increases in pigments from cryptophytes (alloxanthin) and significant but lower increases (39–116%) in those from colonial cyanobacteria (canthaxanthin), but no response from biomarkers of total algal abundance (β‐carotene). In contrast, lakes in catchments with <20% afforestation exhibited no consistent response to forestry practices, although all lakes exhibited fluctuations in pigments and geochemical variables due to peat cutting and upland grazing prior to forest plantation. Taken together, patterns suggest that increases in cyanobacteria and cryptophyte abundance reflect a combination of mineral and nutrient enrichment associated with forest fertilization and organic matter influx which may have facilitated growth of mixotrophic taxa. This study demonstrates that planted forests can alter the abundance and community structure of algae in upland humic lakes of Ireland and Northern Ireland, despite long histories of prior catchment disturbance.     

Abnormalities in flatfishes of the south‐west Atlantic Ocean

Five adult paralichthyid specimens with various kinds of abnormalities are reported from the south‐west Atlantic Ocean. These abnormal flatfish specimens represent the first records of wholly ambicoloured Paralichthys orbignyanus specimens having a deep notch between the eye and dorsal fin and a partially albinistic specimen having skeletal deformities and only the second record of an almost totally ambicoloured specimen. We also report the first observation of reversal in Paralichthys patagonicus and an almost totally ambicoloured, reversed Xystreurys rasile.     

Evolutionary size changes in plants of the south‐west Pacific

Aim To investigate evolutionary changes in the size of leaves, stems and seeds of plants inhabiting isolated islands surrounding New Zealand. Location Antipodes, Auckland, Campbell, Chatham, Kermadec, Three Kings and Poor Knights Islands. Methods First, we compared the size of leaves and stems produced by 14 pairs of plant taxa between offshore islands and the New Zealand mainland, which were grown in a common garden to control for environmental effects. Similar comparisons of seed sizes were made between eight additional pairs of taxa. Second, we used herbarium specimens from 13 species pairs to investigate scaling relationships between leaf and stem sizes in an attempt to pinpoint which trait might be under selection. Third, we used herbarium specimens from 20 species to test whether changes in leaf size vary among islands located at different latitudes. Lastly, we compiled published records of plant heights to test whether insular species in the genus Hebe differed in size from their respective subgenera on the mainland. Results Although some evidence of dwarfism was observed, most insular taxa were larger than their mainland relatives. Leaf sizes scaled positively with stem diameters, with island taxa consistently producing larger leaves for any given stem size than mainland species. Leaf sizes also increased similarly among islands located at different latitudes. Size changes in insular Hebe species were unrelated to the average size of the respective subgenera on the mainland. Main conclusions Consistent evidence of gigantism was observed, suggesting that plants do not obey the island rule. Because our analyses were restricted to woody plants, results are also inconsistent with the ‘weeds‐to‐trees’ hypothesis. Disproportionate increases in leaf size relative to other plant traits suggest that selection may favour the evolution of larger leaves on islands, perhaps due to release from predation or increased intra‐specific competition.     

Assessing the use of sediment organic,carbonate and biogenic silica content as indicators of environmental conditions in Arctic lakes

The objective of this paper is to examine three sediment parameters used in paleolimnological studies, sediment organic, carbonate and biogenic silica (BSi) content, and to quantify the relationship among these parameters and modern environmental conditions for a series of Canadian Arctic lakes. Sediment samples from 63 lakes were analysed for organic, carbonate and BSi content. The environmental and physical parameters of these lakes were recorded. Bedrock composition exerted a very strong influence on sediment organic, BSi and carbonate content, and differences in lake production accounted for much of the remaining variance. The strongest relationships existed among sediment carbonate content, BSi content and water pH. A statistical model developed for predicting water pH provides a new tool for reconstructing past environmental conditions for Arctic aquatic ecosystems. A positive relationship between mean July air temperature and sediment organic and BSi content was detected, but was confounded by effects of bedrock on these parameters. However, the relationship between mean July air temperature and sediment organic and BSi could be even more significant in the context of constant bedrock composition, as is the case in paleolimnological studies.     

Associations of ant species to land cover types and human disturbance in south‐west Gabon

We recorded ground‐foraging ant species in forest and savannah habitats along a 52‐km‐long road planned for upgrade in the buffer zone of the Moukalaba‐Doudou National Park in south‐west Gabon. Sixty stations were established with three sampling points on each side of the future road and baited with peanut butter to record the presence of invasive Wasmannia auropunctata (Roger, 1863). We documented 46 ant species including one genus and eight species not previously reported in Gabon, but no evidence of the presence of W. auropunctata. We also found species known to have an opportunistic behaviour such as Cardiocondyla emeryi (Forel, 1881), Tetramorium simillimum (Smith, 1851) and Trichomyrmex destructor (Jerdon, 1851). Species richness in forested stations was significantly higher than in savannah. Among the most common ant species in the area, we identified 13 associated with forests, eight associated with savannahs and one generalist. Four species were highly tolerant to human disturbance. Our study, even if biased towards stress‐tolerant species, provides new insights about ant species associations with habitats and contributes to the establishment of a reference system to classify African ant species that could be used to monitor the success of restoration of areas impacted by human activities.     

Distribution of saltmarsh plant communities associated with environmental factors along a latitudinal gradient on the south‐west Atlantic coast

Aim To produce an inventory of south‐west Atlantic saltmarshes (from latitude 31°48′ S to 43°20′ S) using remotely sensed images and field sampling; to quantify their total area; to describe the biogeographical variation of the main habitats characterized by dominant vascular plants, in relation to major environmental factors; to test the hypothesis of predominance of the reversal pattern in plant distribution (sedges and grasses dominate the lower, regularly inundated zones, while the upper zones are occupied by more halophytic species) previously described; and to compare these south‐west Atlantic saltmarshes with others world‐wide. Location South‐western Atlantic saltmarshes Methods Field samples of dominant emergent plant species positioned by the global positioning system (GPS) were obtained from most coastal saltmarshes (14) between southern Brazil and northern Patagonia, Argentina. Landsat satellite images were obtained and coastal saltmarsh habitats were quantified by supervised classification, utilizing points gathered in the field. Results Three main plant species dominated the low and middle intertidal saltmarsh, Spartina alterniflora Loesel., Spartina densiflora Brong. and Sarcocornia perennis (P. Mill.) A.J. Scott. The total area of the studied coastal saltmarshes was 2133 km², comprising 380 km² of Sp. alterniflora marsh, 366 km² of Sp. densiflora marsh, 746 km² of Sar. perennis marsh and 641 km² of brackish marsh (dominated by Juncus acutus L., Juncus kraussii Hochst., Scirpus maritimus L., Scirpus americanus Pers. and Phragmites australis (Cav.) Trin.). Cluster analysis showed three habitat types: saltmarshes dominated by (1) Sp. densiflora and brackish species,(2) Sp. alterniflora and Sar. perennis and (3) Sp.densiflora only. The analysis of abiotic variables showed significant differences between groups of habitats and coordinated gradients of the abiotic variables. The south‐west Atlantic coast showed decreasing mean annual rainfall (1200 to 196 mm) and increasing mean tidal amplitude (< 0.5 to > 2.5 m) from latitude 31° to 43°. Main conclusions South‐west Atlantic saltmarshes are globally important by virtue of their total extent. Remote sensing showed that the reversal pattern in plant distribution is not widespread. Indeed, south‐west Atlantic saltmarshes are better characterized by the presence of the halophytic genera Spartina and Sarcocornia. Our results support the interpretation that south‐west Atlantic saltmarshes constitute a class of temperate type (sensu Adam, 1990 ) with transitional characteristics between Australasian–South African saltmarshes and west Atlantic saltmarshes.     

Control charts for improved decisions in environmental management: a case study of catchment water supply in south‐west Western Australia

Environmental monitoring is becoming increasingly sophisticated with the widespread adoption of data loggers, sensor arrays and remote sensing, leading to larger scale, higher resolution and superior quality data. However, interpreting monitoring data and deciding when and how to apply environmental management remains a subjective and underdeveloped area of research. Control charts, developed in industrial settings to identify when manufacturing processes were beyond the acceptable bounds of production quality, represent one solution. Despite their potential utility, control charts have rarely been adopted in environmental monitoring. In theory, they are able to identify undesirable trends early and provide transparent and broadly consensual criteria for defining when management action should take place, that is action is triggered when parameter values are observed beyond the agreed control limits of the process. Once triggered, a predetermined management action is implemented. Possible actions are many and varied, and range from investigation and increased monitoring to intervention in the system. Here, the utility of control charts in monitoring water supply in south‐western Australia from 1911 to 2010 is examined, and their ability to provide an early, transparent and easily understandable means of triggering management action is assessed. Two control chart types are applied: the X‐bar chart and the CUSUM chart. X‐bar charts varied widely in their ability to trigger action and were insensitive to many traditional threshold criteria (of which there are many to choose from). In contrast, standard CUSUM charts are specifically designed to detect subtler shifts away from a mean trend and hence provided a more consistent warning of the decline in water supply. While managers were aware of the decline in water supply from an early stage, we believe that control charts could have clearly communicated this earlier, enabling consensus among decision makers to be reached more rapidly.     

Seasonal response of nutrients to reduced phosphorus loading in 12 Danish lakes

1. Concentrations of phosphorus, nitrogen and silica and alkalinity were monitored in eight shallow and four deep Danish lakes for 13 years following a phosphorus loading reduction. The aim was to elucidate the seasonal changes in nutrient concentrations during recovery. Samples were taken biweekly during summer and monthly during winter. 2. Overall, the most substantive changes in lake water concentrations were seen in the early phase of recovery. However, phosphorus continued to decline during summer as long as 10 years after the loading reduction, indicating a significant, albeit slow, decline in internal loading. 3. Shallow and deep lakes responded differently to reduced loading. In shallow lakes the internal phosphorus release declined significantly in spring, early summer and autumn, and only non‐significantly so in July and August. In contrast, in deep lakes the largest reduction occurred from May to August. This difference may reflect the much stronger benthic pelagic‐coupling and the lack of stratification in shallow lakes. 4. Nitrogen only showed minor changes during the recovery period, while alkalinity increased in late summer, probably conditioned by the reduced primary production, as also indicated by the lower pH. Silica tended to decline in winter and spring during the study period, probably reflecting a reduced release of silica from the sediment because of enhanced uptake by benthic diatoms following the improved water transparency. 5. These results clearly indicate that internal loading of phosphorus can delay lake recovery for many years after phosphorus loading reduction, and that lake morphometry (i.e. deep versus shallow basins) influences the patterns of change in nutrient concentrations on both a seasonal and interannual basis.     

N2 fixation in phototrophs: adaptation to a specialized way of life

Phototrophic diazotrophs include the photosynthetic green and purple bacteria, the heliobacteria, many cyanobacteria and the unusual chlorophyll-containing rhizobia that are found in the stem nodules of Aeschynomene spp. In this review, which concentrates on cyanobacteria, the interrelations between photosynthesis and N₂ fixation are discussed. Photosynthesis can, in theory, directly provide the ATP and reductant needed to support N₂ fixation but the link between these two processes is usually indirect, mediated through accumulated carbon reserves. In cyanobacteria, which possess an oxygenic photosynthesis, this serves to separate the O₂ that is produced by photosynthesis from the O₂-sensitive nitrogenase. However, in certain circumstances, oxygenic photosynthesis and N₂ fixation coexist. Under these conditions, respiratory consumption of photosynthetically generated O₂ may have an important role in minimizing O₂-damage to nitrogenase.     

Outbreak of an invasive paropsine beetle in south‐west Ireland: preference,performance and damage to Eucalyptus

An exotic, paropsine beetle –Paropsisterna nr. gloriosa Blackburn – occurred at high densities in south‐west Ireland in 2007. In bioassays, adults and larvae fed on foliage from a variety of eucalypt species. Eggs and neonates occurred only in association with new foliage. Despite their ability to consume old foliage, adult beetles had a high preference for new leaves with low specific leaf weights (softer leaves). In choice tests, adults that depleted new foliage of their preferred host, moved to new foliage of a second host but not older foliage of the preferred host. A 2008 survey of southern Ireland indicated that P. nr. gloriosa was restricted to County Kerry, largely associated with foliage plantations in that county. The distribution of damage suggests that the initial spread of the beetle was facilitated by foliage‐trade activities. Eucalyptus parvula L.A.S. Johnson & K.D. Hill was the most heavily damaged species at many plantations. Eucalyptus pulverulenta Sims and Eucalyptus cordata Labill. were highly resistant to the beetle as indicated by low levels of damage in the field and reduced fitness of larvae in feeding trials. Nevertheless, at the plantation with the highest overall levels of damage, adult beetles moved to feed on E. pulverulenta. A progressive dispersal from plantations also caused slight damage to neighbouring ornamental eucalypts. Clear preferences by P. nr. gloriosa for new foliage, irrespective of eucalypt species, suggests that pollarding – the removal of top branches to produce dense juvenile foliage – accelerated population build‐up during 2007.     

Highest catch of the vulnerable broadnose sevengill shark Notorynchus cepedianus in the south‐west Atlantic

An exceptional catch of 97 broadnose sevengill sharks Notorynchus cepedianus in Samborombón Bay, Argentina, in 2013 is described from a single overnight gillnet fishing operation. Sixty‐five female and 32 male N. cepedianus, ranging in size between 105–201 and 112–190 cm L_T, respectively, were recorded in this catch. Fishers' observations and published information suggest that this species aggregates in the area seasonally for feeding.     

Contrasting diversity and demographic signals in sympatric narrow‐range endemic shrubs of the south‐west Western Australian semi‐arid zone

Comparative studies of sympatric species that integrate both phylogeographical and population genetic approaches provide insight into how demographic events and life history traits shape adaptive potential and drive species persistence. Such studies are rare for species‐rich and strongly structured environments, especially those of the southern hemisphere. For two sympatric, perennial shrubs of the south‐west Western Australian semi‐arid zone, Grevillea globosa and Mirbelia sp. Bursarioides, we assessed historical and contemporary genetic diversity and structure, demographic processes and ratios of pollen to seed dispersal. Phylogeographical structure was not detected and haplotype networks were star‐like. Number of haplotypes, nucleotide diversity, haplotype diversity, and allelic diversity were statistically significantly lower for G. globosa than for M. sp. Bursarioides. Levels of haplotype divergence and more contemporary genetic divergence and expected heterozygosity were lower for G. globosa than for M. sp. Bursarioides, but differences were not statistically significant. Both species exhibited signals of isolation by distance and low pollen to seed dispersal ratios (5.26:1 and 6.88:1). Grevillea globosa displayed signals of historical and contemporary demographic expansion. Results imply an important role for aspects of seed ecology that impact population demography, as well as direct dispersal and a significant contribution of seed dispersal to genetic connectivity in a semi‐arid landscape.     

Acclimation of photosynthetic characteristics of the moss Pleurozium schreberi to among‐habitat and within‐canopy light gradients

Light availability varies strongly among moss habitats and within the moss canopy, and vertical variation in light within the canopy further interacts with the age gradient. The interacting controls by habitat and canopy light gradient and senescence have not been studied extensively. We measured light profiles, chlorophyll (Chl), carotenoid (Car) and nitrogen (N) concentrations, and photosynthetic electron transport capacity (J_max) along habitat and canopy light gradients in the widespread, temperate moss Pleurozium schreberi to separate sources of variation in moss chemical and physiological traits. We hypothesised that this species, like typical feather mosses with both apical and lateral growth, exhibits greater plasticity in the canopy than between habitats due to deeper within‐canopy light gradients. For the among‐habitat light gradient, Chl, Chl/N and Chl/Car ratio increased with decreasing light availability, indicating enhanced light harvesting in lower light and higher capacity for photoprotection in higher light. N and J_max were independent of habitat light availability. Within the upper canopy, until 50–60% above‐canopy light, changes in moss chemistry and photosynthetic characteristics were analogous to patterns observed for the between‐habitat light gradient. In contrast, deeper canopy layers reflected senescence of moss shoots, with pigment and nitrogen concentrations and photosynthetic capacity decreasing with light availability. Thus, variation in chemical and physiological traits within the moss canopy is a balance between acclimation and senescence. This study demonstrates extensive light‐dependent variation in moss photosynthetic traits, but also that between‐habitat and within‐canopy light gradient affects moss physiology and chemistry differently.     

Susceptibility of table grape varieties grown in south‐eastern Italy to Drosophila suzukii

Since 2008, Drosophila suzukii, the spotted wing drosophila, has colonized most of the American and European continents, being able to adapt to very different climates. In Italy, this pest has been captured from northern Alpine to southern Mediterranean regions where it can infest a broad range of fruits, including wine grapes. Studies have shown that oviposition levels and developmental rates of D. suzukii on wine grapes are lower than on other berries, although recent observations indicate that grapes may become a suitable host plant in particular conditions. Here, we report, for the first time, the results of a series of no‐choice oviposition experiments using berries of five table grape varieties sampled in the provinces of Taranto and Bari (Apulia region, south‐eastern Italy) during 2013 from both organic and conventional farming systems. The sugar content (SC) and skin hardness of each sample were analysed to assess the influence of these physiological parameters on the susceptibility of table grapes to D. suzukii infestation. A negative correlation was found between the number of eggs laid and berry skin penetration force, whereas there was a positive one between the number of eggs and Brix values, as well as sampling date. In organic grapes, SC and skin hardness of two varieties (“Crimson” and “Scarlotta”) were measured, respectively, higher and lower than in conventional grapes, thus making them more susceptible to pest infestation. The study hence shows that in laboratory conditions D. suzukii is able to heavily infest and develop on table grapes and that susceptibility to its infestation significantly depends on both variety and farming system.     

Five new records of Luvarus imperialis (Acanthuroidei: Luvaridae) in the south‐west Atlantic Ocean

Five new records of louvars Luvarus imperialis are documented for the south‐west Atlantic Ocean, extending its distribution range in this ocean. The presence of one ripe specimen, associated with the previous records of larvae and juveniles, suggests that L. imperialis spawn in this region. The possible association of juveniles with shoals of skipjack tuna Katsuwonus pelamis is discussed.     

Responses of community structure of amoA‐encoding archaea and ammonia‐oxidizing bacteria in ammonia biofilter with rockwool mixtures to the gradual increases in ammonium and nitrate

Aims

To investigate community shifts of amoA‐encoding archaea (AEA) and ammonia‐oxidizing bacteria (AOB) in biofilter under nitrogen accumulation process.

Methods and Results

A laboratory‐scale rockwool biofilter with an irrigated water circulation system was operated for 436 days with ammonia loading rates of 49–63 NH₃ g m^?3 day^?1. The AEA and AOB communities were investigated by denaturing gradient gel electrophoresis, sequencing and real‐time PCR analysis based on amoA genes. The results indicated that changes in abundance and community compositions occurred in a different manner between archaeal and bacterial amoA during the operation. However, both microbial community structures mainly varied when free ammonia (FA) concentrations in circulation water were increasing, which caused a temporal decline in reactor performance. Dominant amoA sequences after this transition were related to Thaumarchaeotal Group I.1b, Nitrosomonas europaea lineages and one subcluster within Nitrosospira sp. cluster 3, for archaea and bacteria, respectively.

Conclusions

The specific FA in circulation water seems to be the important factor, which relates to the AOB and AEA community shifts in the biofilter besides ammonium and pH.

Significance and Impact of the Study

One of the key factors for regulating AEA and AOB communities was proposed that is useful for optimizing biofiltration technology.