An assessment of diurnal water uptake in a mesic prairie: evidence for hydraulic lift?

Hydraulic lift, the passive movement of water through plant roots from wet to dry soil, is an important ecohydrological process in a wide range of water-limited ecosystems. This phenomenon may also alter plant functioning, growth, and survival in mesic grasslands, where soil moisture is spatially and temporally variable. Here, we monitored diurnal changes in the isotopic signature of soil and plant xylem water to assess (1) whether hydraulic lift occurs in woody and herbaceous tallgrass prairie species (Rhus glabra, Amorpha canescens, Vernonia baldwinii, and Andropogon gerardii), (2) if nocturnal transpiration or grazing by large ungulates limits hydraulic lift, and (3) if a dominant grass, A. gerardii, utilizes water lifted by other tallgrass prairie species. Broadly, the results shown here suggest that hydraulic lift does not appear to be widespread or common in this system, but isolated instances suggest that this process does occur within tallgrass prairie. The isolated instance of hydraulic lift did not vary by grazing treatment, nor did they result in facilitation for neighboring grasses. We suggest that the topographic complexity of this tallgrass prairie and the high rates of nocturnal transpiration observed in this study likely limit the frequency and occurrence of hydraulic lift. These results suggest that hydraulic lift can be a patchy process, particularly in heterogeneous landscapes.     

A “toy model” analysis of causes of nitrogen limitation in terrestrial ecosystems

Nitrogen (N) limitation to net primary production is widespread and influences the responsiveness of ecosystems to many components of global environmental change. Logic and both simple simulation (Vitousek and Fieldin in Biogeochemistry 46: 179–202, 1999) and analytical models (Menge in Ecosystems 14:519–532, 2011) demonstrate that the co-occurrence of losses of N in forms that organisms within an ecosystem cannot control and barriers to biological N fixation (BNF) that keep this process from responding to N deficiency are necessary for the development and persistence of N limitation. Models have focused on the continuous process of leaching losses of dissolved organic N in biologically unavailable forms, but here we use a simple simulation model to show that discontinuous losses of ammonium and nitrate, normally forms of N whose losses organisms can control, can be uncontrollable by organisms and can contribute to N limitation under realistic conditions. These discontinuous losses can be caused by temporal variation in precipitation or by ecosystem-level disturbance like harvest, fire, and windthrow. Temporal variation in precipitation is likely to increase and to become increasingly important in causing N losses as anthropogenic climate change proceeds. We also demonstrate that under the conditions simulated here, differentially intense grazing on N- and P-rich symbiotic N fixers is the most important barrier to the responsiveness of BNF to N deficiency.

     

Educational values and services of ecosystems and landscapes – An overview

Education is one of the multiple services that ecosystems and landscapes provide to societies. Despite its importance to formal and informal learning and nature-based, cognitive tourism, it is hardly taken into account in the various quantification approaches of ecosystem services. The article provides an overview of landscape educational values and the educational ecosystem service. Here, the forms of the use of landscape educational values have been summarised and the indicators for the quantification of the educational ecosystem service proposed in the literature reviewed. The criteria for the evaluation of the educational values of landscape were acquired from the literature and discussed. In order to obtain more practical viewpoints on those criteria, an exploratory survey with young experts (n = 37) from two universities of environmental sciences was conducted. Within this step, the expert method for the evaluation of the educational values of landscapes was applied. However, the results show an extremely high level of subjectivity and dependence on personal experience regarding outdoor environmental education. Nonetheless, the article can contribute to acquiring knowledge in cultural ecosystem service assessment and the application of this concept, especially in terms of the criteria and indicators which can be potentially used for the assessments.     

“ELISA” as an aid in the identification of fish and molluscan prey of birds in marine ecosystems

A serological technique known as ELISA (enzyme-linked immunosorbent assay) was used in an attempt to aid the identification of visually unidentifiable seabird stomach contents. A series of seabird-prey muscle-protein antisera was established. When these antisera were tested against pieces of digested and undigested prey species, the ELISA technique detected the prey from both digested and undigested samples. This method also enabled rapid quantitative analysis of the samples.     

Is southern Africa different? An investigation of the relationship between leaf physiognomy and climate in southern African mesic vegetation

Leaves from 24 South African vegetation sites, including 3 Fynbos sites, exhibiting high levels of endemism, were assessed by both LMA (Leaf Margin Analysis) and CLAMP (Climate Leaf Multivariate Program) to determine the effect of endemism on these palaeoclimate proxies. We examined whether existing calibrations using either locally recorded climate data or globally gridded climate data are appropriate for South Africa, or whether new calibrations specific to the region provide more accurate results. The results suggest that calibrations using gridded data yield slightly cooler estimates using LMA when the percentage of entire margined species is over 25. Overall, however, the differences are small and both gridded and local climate station calibration data can be used with equal accuracy. Xeric sites differ from mesic sites regarding the relationship between leaf margin proportion (LMP) and MAT, but with the exception of Fynbos sites, the differences are small when the percentage of entire margined species is < 65. Fynbos sites plot up to 8 °C cooler for a given leaf margin percentage (LMP) than do other sites. LMA was also sensitive to the number of taxa scored and in general should not be attempted on less than 15 leaf morphotypes per site. For CLAMP, the African non-Fynbos sites plotted within the parameters characterized by the existing PHYSG3BRC data set, indicating that they had a leaf physiognomic response to climate consistent with that of the rest of the world. However, the African non-Fynbos sites did fill a previously unoccupied void within that space, indicating the existence of a regional variance from the global pattern. This suggests that endemism per se does not prevent CLAMP from yielding reliable climate predictions. The inclusion of African non-Fynbos sites into the calibration improved the ability of CLAMP to predict Fynbos site climate, although this remained poor for non-coastal xeromorphic Fynbos vegetation. The addition of the African non-Fynbos vegetation did not degrade significantly the PHYSG3BRC calibration, particularly regarding key climatic variables such as enthalpy. Enthalpy appears to be a particularly robust variable with which to test climate model performance against CLAMP palaeoclimate predictions.     

Windthrows in forests of Kostroma oblast and neighboring lands in 1984–2011

A retrospective analysis of windthrows in southern taiga forests (Kostroma oblast and neighboring lands) is performed. The main traits of massive windthrows are calculated. The dominant spatial forms of windthrows are identified. The average annual rates of the forest-cover damage from clearcuts, forest fires, and windblows are compared. The topographical effect on the spatial distribution of fragments of massive windthrows is analyzed.     

An “Inclusion-Body-Like” Configuration of Some Cell Nuclei in Moose

At routine post-mortem of a moose an inclusion-body-like configuration of the nuclei of the cells in the granule layer of the cerebellum was found. This was also observed to a lesser extent in glial cells of the cerebrum, epithelial cells of the collecting tubules of kidney and in the hepatocytes.     

Contributions of subterranean termites to the “economy” of Chihuahuan desert ecosystems

Summary We examined the role of subterranean termites in decomposition of cattle dung, various herbaceous plant species and wood in a Chihuahuan desert ecosystem. From July–September, termites removed dung at a rate of 0.63 g day^-1 accounting for a percent mass loss of 19.5–100%. During the autumn subterranean termites consumed more than 50% of the leaves of the shrub Larrea tridentata, the grass Erioneuron pulchellum and annual plant Lepidium lasiocarpum and Baileya multiradiata but used very little of two other annuals Eriastrum diffusum and Eriogonum trichopes. Yucca inflorescence stalks on plots with termites lost 23% of their original mass in 30 months while those on termite free soils lost 11%. Elimination of termites resulted in reduction of fluff grass, Erioneuron pulchellum biomass, thereby affecting the structure of the ecosystem.     

Issues of ecosystem-based management of forage fisheries in “open” non-stationary ecosystems: the example of the sardine fishery in the Gulf of California

The Gulf of California system presents major challenges to the still developing frameworks for ecosystem-based management (EBM). It is very much an open system and is intermittently subject to important influxes of migratory visitors, including large pelagic predatory fishes and small pelagic forage fishes. These migrants include the more tropical species from the coastal ecosystems to the south and perhaps subtropical sardines and anchovies from the California Current upwelling system. In addition to the multi-annual ENSO-scale and what may seem to be rather erratic episodes of major population incursions, the Gulf presents nonstationary, transient aspects on a variety of longer time scales. Moreover, the removal of top predators by commercial and sport fisheries has introduced trends that must be affecting the entire ecosystem, and certainly the forage fishes that are their major prey base. In addition to size limits, fishing seasons, area closures and license limitations, the fishery is managed by an ad hoc adaptive management system, in which the fishing season can be shortened or additional areas closed to fishing if pre-season exploratory fishing surveys indicate a shortage of small pelagic fishes on the fishing grounds. Whether this system is likely to be sustainable in the long term is difficult to determine, given the potential for rapid changes in the system because of environmental changes and/or feedbacks within the food web. Thus it appears that innovative management frameworks, among other things utilizing the comparative method, may be required in order to determine defensible tradeoffs between precaution and resource utilization.     

Current status of heavy metal contamination in Asia’s rice lands

Major contribution (over 90 %) to the world’s rice production is coming from Asia, where metal contamination of agricultural lands is often reported. Thus the present paper reviews the sources and current status of heavy metal contamination of paddy lands in the region. Apart from the natural sources, agrochemicals, wastewater irrigation, sewage sludge application, livestock manures, mining and fly ash etc., could be identified as the key sources of metal contamination in Asia. Accumulation of heavy metals and metalloids (Cd, Zn, Cu, Pb, Cr, Ni, Fe, Zn, Co, Hg and As) in different parts of the rice plant (roots, straw, hull and grain) is reported at varying degrees. Rice grain accumulates the least amount of toxic metals compared to hull, straw and roots. Most importantly, a greater number of investigations confirmed that the metal contents in rice grains are within the permissible limits of Codex recommendations of joint Food and Agriculture Organization/World Health Organization Food Standards Programme and/or food regulations imposed by the respective governments. However, due to the fact that rice is a main route of human exposure to heavy metals, appropriate preventive and remedial measures should be enforced in the areas with potential risk of metal contamination.     

Sonneratia apetala Buch.Ham in the mangrove ecosystems of China: An invasive species or restoration species?

By the end of 1990s when China initiated a 10-year mangrove reforestation project, the mangrove forest area had decreased from 250,000 to 15,000 ha. Over 80% of current Chinese mangroves are degraded secondary forests or plantations. As an initial restoration and reforestation effort, Sonneratia apetala, a native of India, Bengal and Sri Lanka, was introduced in 1985 to Dong Zhaigang Mangrove Nature Reserve in Hainan Island from Bengal. It has then been introduced into other places since 1991. However, the further use of the species is becoming increasingly controversial as there are emerging signs that it may become invasive in certain locations. A comprehensive evaluation of the species’ condition in China regarding benefits and risks is critically needed. Here, we map the introduction and dispersal routes and monitor the growth of S. apetala in China from 1985 to 2006. S. apetala grows fast and performs well in the introduced 2300 ha muddy beaches area. It greatly improves the soil fertility and shows a suite of suitable characteristics as a pioneer restoration species. Currently, no natural invasion of S. apetala has been observed in the northern mangrove area. However, invasion into natural forests does occur in southerly locations such as Shenzhen, Zhanjiang and Dong Zhaigang. In these locations, S. apetala exhibits invasive characteristics such as overgrowth and high spreading ability that evidently affects local mangrove ecosystem structure and function. While the species clearly offers some benefits at some locations where it cannot naturally invade, it appears harmful to other native mangrove species, posing a major practical problem to both ecologists and land managers. This situation will be similar to previously imported non-native and invasive intertidal wetland species, Spartina alterniflora (smooth cordgrass), with similar results and problems.     

Impacts of invasive biota in forest ecosystems in an aboveground–belowground context

Forest ecosystems world-wide are being subjected to invasion by organisms representing all domains of life. Here we use a combined aboveground-belowground approach to provide a conceptual framework for assessing how forests respond to biological invasions. We first address mechanisms by which invasive plants and aboveground and belowground consumers impact on forests, and highlight that although we have a growing understanding of the determinants of the effects of invasive plants, for invasive consumers we have yet to move from a series of iconic case studies to the development of general principles. We also address the effects of invasive biota in the context of the drivers of invasion, co-invasion and invasional meltdown, the issue of simultaneous species gains and losses, and forest restoration and recovery post-invasion. We then highlight areas that would benefit from further work, particularly regarding underlying mechanisms, determinants of context-dependency of invader effects, and linkages between causes and consequences of invasion. In concluding, we emphasize that biological invaders have the potential for large-scale and long-term impacts on forest processes, and consideration of these impacts in an aboveground-belowground context will enable better prediction of future responses of forests to invaders and their management as well as of restoration efforts.     

An ambiguity in the notion “function”

Responses

An ambiguity in the notion function     

An initial survey on the occurrence of staphylococcal infections in Turkish marine aquaculture (2013–1014)

A tentative survey on selected marine fish farms was undertaken to delineate the extent to which infections with Staphylococcus species occur in Turkish aquaculture systems. To determine the presence and the distribution of fish pathogenic staphylococci, representative farm types such as marine cages as well as inland pond farms working with saline-ground water and a large hatchery were selected. Field sampling was performed in a total of 13 commercial fish farms that are located in the most-popular aquaculture sites of Turkey. Samples were taken between October 2013 and August 2014. Almost all size classes of the most commonly marine cultured fish species in Turkey were investigated, including Dicentrarchus labrax, Sparus aurata, Argyrosomus regius, Diplodus puntazzo, Dentex dentex, Onchorhynchus mykiss and Salmo labrax. After a visual check, specimens with various clinical signs were sampled for bacteriological and histopathological investigations. Mixed infections of staphylococci along with Vibrio and Aeromonas representatives were detected in Dicentrarchus labrax, Sparus aurata and Diplodus puntazzo samples obtained from 7 farms. The following pathogens were identified: Staphylococcus. epidermidis, S. aureus, S. capitis subsp. capitis, S. lentus, S. hominis subsp. hominis and S. sciuri subsp. sciuri. Main clinical and histopathological effects of the infections in fishes were revealed. The pathogenicity of some isolates was confirmed with in vivo pathogenicity assay and SDS-PAGE analysis.     

Introduction to the Special Issue “Functional monitoring in megadiverse tropical ecosystems”

Land-use and climate change are major threats to biodiversity and ecosystem functions. Most of the current biodiversity monitoring systems are based on periodic records of the populations of a set of threatened or popular ‘flagship’ indicator species. In contrast to the abundance-based monitoring of species, also specific indicators of processes and functional interactions in an ecosystem may become targets of a more functional monitoring which can unveil early responses of an ecosystem to environmental changes at different spatial and temporal scales. The contributions of this Special Issue present such functional indicators for assessing and predicting responses to environmental changes of ecosystem functions in a hotspot of tropical biodiversity.