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Global grassland degradation poses a significant threat to the sustainable socio-economic development of humanity. However, this trend can be effectively mitigated through scientifically sound and rational grassland improvement measures. Grassland improvement utilizes the theory of pratacultural science, especially the theory of the four production levels of grassland agro-ecosystems, to solve the fundamental contradiction between the seasonal imbalance of grassland supply and livestock demand through integrates a number of improvement techniques. In order to clarify the implementation subject, target and specific measures of grassland improvement and to improve the science and efficiency of management and conservation, we classify grassland improvement into four types according to the target, scale and attributes of grassland and livestock feedback mechanism. Grassland improvement is generally based on one key technology, with multiple technologies used in combination, and synergy or superposition formed between integrated technologies. Individual technologies mainly include enclosure of livestock, reclamation, ripping, overseeding, fertilization, irrigation, fire work and grazing management, while integrated technologies are a combination of two or more technologies. Compared to individual techniques, the integrated approach resulted in a significant enhancement of community aboveground biomass by 17–38% and species richness by 2–24%, with no discernible impact on soil properties in the short term. The establishment of a standardized grazing-based improvement process while adhering to the principles of improvement after utilization, comprehensiveness, standardization and scale consistence to improve the structure and function of grassland ecosystems. Strategy of grassland improvement reassesses "nuisance" species as "citizens" of the ecosystem because they supply productivity, species biodiversity and other ecosystem services, and they can be managed at an unharmful and even benefitful level through identifying the ecological and economic thresholds. • Classification methods and principles of grassland improvement are proposed. • A standardized process for grassland improvement was proposed and validated. • Proposing a new method for calculating livestock carrying capacity. • Elucidating the role of grazing effects in grassland improvement. [ABSTRACT FROM AUTHOR]

Abstract Temperature is an important controlling factor in the growth activity of all microorganisms. Aerobic anoxygenic phototrophic (AAP) bacteria actively grow in the ocean and are known as one of the main driving forces in organic matter cycling in surface seawater environments. Whether temperature change affects AAP bacteria activity from an ecological viewpoint remains an open question. To date, no known studies have reported the effect of temperature change on AAP bacteria growth in the ocean. We here show that the growth rate of AAP bacteria exceeded that of other bacterial types at high water temperatures in the absence of grazers. The slope of the regression line of the net growth rate of AAP bacteria as a function of water temperature was the same as that for non‐AAP bacteria at all temperatures (10, 20, and 30°C); however, when grazers were eliminated, it was 4.7 times higher than that of non‐AAP bacteria. This result suggests that AAP bacteria are more responsive to water temperature increases than other bacteria and that AAP bacteria might become more dominant than other bacteria under elevated water temperatures.

The effect of grazing on desert plant species from three distinct habitats i.e. Kot Diji sand dune, Ubhan Shah flat dune and Sorah inter-dunal area of District Khairpur was studied by using quadrat method. We analyzed each plant species for cover, total plant cover of grazed, un-grazed and mean % reduction in cover (cm) from pre-monsoon and post-monsoon seasons. The results revealed a considerable effect of grazing on plant species; however the impact of grazing varied from plant to plant and season to season, in the studied areas. There was highest grazing intensity of Indigofera species leading to endanger in this area. In all sites, maximum reduction in cover was observed in Indigofera oblongifolia and Indigofera argentea, with 62.8 and 57.2cm, respectively during pre-monsoon, and 61.5 and 52.8cm in post-monsoon. Aristida funiculata also possesses high grazing intensity with 40.3 and 54.2cm in pre and post-monsoon seasons respectively. The species Convolvulus protratus, Cassia italica, Dipterygium glaucum and Digera arvensis showed grazing intensities with 47.8, 57.4, 25.2, 42.7 in pre-monsoon season and 44.3, 35.9, 45.7,53.7 in post monsoon seasons, respectively. The low grazing intensity was observed in dominant plant communities Aerva javanica, Calligonum polygonoides, and Leptadenia pyrotechnica in a pre-monsoon season with 7.8, 17.4, 13.2cm, whereas, it was increased in post-monsoon with 11.5, 25.9, 32 in the reduction of cover (cm), respectively. These plant species were grazed by the animals at that time when ephemerals were not available in the desert during a drought period. It is suggested that partial protection and controlled grazing can be beneficial to get positive results and maintain the desert vegetation in the study area. [ABSTRACT FROM AUTHOR]

Overgrazing has become an ecological problem in the wide steppes of Mongolia due to rapid livestock growth in the last two decades. Species diversity and productivity of biological communities, along with information on the presence and absence of certain species, can be indicators of environmental health to assess the state of pasture. Moths have been used as indicator species in various studies as they are abundant in many different habitats and sensitive to environmental changes. We used moths as indicators for pasture degradation in the Mongolian steppe for the first time. In this study, we investigated how overgrazing affected moth species diversity, identified indicator species for degraded pasture and collected baseline data to study distribution and migration of moths under future climate change. To accomplish these objectives, we compared moth diversity in plots with different grazing intensity in two locations in central Mongolia. Species diversity of moths was two times higher in lightly grazed plots than in medium-grazed and heavily grazed plots. Thus we conclude that pasture degradation affected moth diversity negatively. As a result of indicator species analysis we identified four indicator species for heavily grazed plots ( Leucoma salicis, Autographa buraetica, Mythimna impura and Pelochrista arabescana ) and seven indicator species for lightly grazed plots ( Panchrysia dives, Gastropacha quercifolia, Selagia argyrella, Lymantria dispar, Mythimna conigera, Stigmatophora micans and Perconia strigillaria ). The meadow moth Loxostege sticticalis was most abundant in all plots. In this study we collected a total of 115 species from Ikhtamir and Undurshireet as baseline data in order to study distribution and migration of moths under future climate change. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze the effects of grazing, precipitation and temperature factors on plant species dynamics (diversity and composition) in the semi-steppe of Isfahan semi-arid rangelands, Iran. The effects of Sheep grazing were studied in a controlled experiment along grazing gradient with seven intensities (from very heavily grazed to nongrazed) during six consecutive years (2006–2011). The results show that plant species dynamics varied among years, but were only slightly affected by grazing intensity. Since the experimental years were much dryer than the long term average, the abiotic constraints may have overridden any grazing effect. The differences among the years were predominantly determined by the abiotic factors of temperature and precipitation. Most of the variations in species dynamics and coexistence between the C4and C3species were explained by seasonal weather conditions, i.e., temperature and precipitation regimes during the early season (March-June). The dominant C3species,Poa bulbosa, was highly competitive in March-June at low and high temperature and rainfall levels, respectively. In contrast, the most common C4speciesCynodon dactylonbenefited from high and low early season temperature and rainfall levels, respectively. However, biomass ofP. bulbosawas positively correlated with temperature in March, when effective mean temperature ranges from 0 to 5°C and thus promotes vernalization and vegetative sprouting. Our results suggest that, over a six-year period, it is temporal variability in temperature and precipitation rather than grazing that determines vegetation dynamics and species distributions in grazed semi-steppe ecosystems. Our results also support that the variability in the dominant species biomass, rather than diversity, determine ecosystem functioning. This study provides fundamental knowledge on the complex interaction of climate, vegetation, and grazing. [ABSTRACT FROM AUTHOR]

• The effects of livestock grazing on small felids are poorly understood, due to the low detectability of species. • Employing camera trap data, we evaluated the effect of grazing on occupancy by the Andean and Pampas cats. • Occupancy models showed negative effects of camelid abundance on Andean cat and Pampas cat. • We suggest mechanisms can be implemented to compensate the negative effects of livestock on small cats populations. Human activities lead to declines in species' abundance and diversity, as well as loss of habitat quality from overexploitation. The effects of livestock grazing increase on small felids are poorly understood, primarily due to the low detectability of these species. The grazing of domestic camelids, such as the llama (Lama glama) and the alpaca (Vicugna pacos), is the main traditional source of income for the inhabitants of the Andes, where the Andean cat (Leopardus jacobita) and Pampas cat (L. colocolo) are also present. In this study, we employ camera trap data to evaluate the association of llama and alpaca grazing with occupancy by the Andean and Pampas cat in Sajama National Park. In each of 36 sampling stations, we installed a camera trap, a grid of traps for rodents and two habitat transects along a gradient of intensity of livestock grazing. Occupancy models showed that negative effect of camelid abundance was stronger for the Andean cat than the Pampas cat. For both species, occupancy was also associated positively to the abundance of prey, proximity to water bodies, and vegetation. Given that livestock activity is a way of life for human populations in the Andes, we suggest that mechanisms should be implemented to compensate for the negative effects of livestock on Andean and Pampas cat populations. [ABSTRACT FROM AUTHOR]

Coral reef and atoll lagoons are among the most diversified marine ecosystems but also the most affected by the combined effects of climate change and human activities. The Iles Eparses (Scattered Islands) in the Western Indian Ocean have been little affected by human pressure and can be considered to be “pristine” ecosystems. Metazooplankton plays a major role in the functioning and productivity of aquatic ecosystems, and this study was undertaken: (i) to determine the spatial abundance, distribution and species composition of metazooplankton, (ii) to assess the effect of metazooplankton grazing on pico- and nanophytoplankton and (iii) to analyze the trophic positions of metazooplankton by using the stable isotope signatures of a wide variety of taxa and particulate organic matter from the Iles Eparses and Mayotte. Tromelin Island (which is not located in the Mozambique Channel) had the lowest metazooplankton abundance with no cyanobacteria Trichodesmium spp. or mollusks (pteropods) presence, and with δ 15 N signatures of organisms that were higher than for the islands in the Mozambique Channel. Trichodesmium spp. was found in the Mozambique Channel and the plankton food web was probably based preferentially on these cyanobacteria with lower δ 15 N signatures indicating direct or indirect trophic transfer of diazotrophic nitrogen to metazooplankton. Three of the islands were distinct: Europa had the highest proportion of copepods, with oithonids being dominant, which is typical of rich mangrove systems, while Juan de Nova and Mayotte seemed to be the sites most affected by human activity with a high abundance of appendicularians and distinct particulate organic matter ∂ 13 C signatures. Grazing experiments showed that food could be a limiting factor for metazooplankton in the Iles Eparses. However, the effect of metazooplankton grazing on phytoplankton appeared to be very low (0.01–2.32% of the total phytoplankton per day). [ABSTRACT FROM AUTHOR]

The article presents a study which examined the potential of krill Euphausia superba to control phytoplankton biomass in the northern Antarctic water of South Georgia in South Georgia & South Sandwich Islands. The study used a linear model to determine the main factors involved in phytoplankton biomass differences. It evaluated the role of bottom-up factors and krill grazing in controlling phytoplankton and calculated the nutrient depletion to make regional comparisons. Charts that depict the findings of the study are also presented.

Abstract: The main objective of the paper is to investigate the enhancement of the heat and mass transfer characteristics for a NH3/H2O bubble absorption process using the CNTs-ammonia binary nanofluid as a working medium. Using the surface modification of CNTs, the CNTs-ammonia binary nanofluid is successfully prepared without the addition of any dispersants. The effects of the mass fraction of CNTs, the initial concentration of ammonia in the binary nanofluid and the flow rate of ammonia vapor on NH3/H2O bubble absorption are studied experimentally. The mechanism of the binary nanofluid enhancing bubble absorption is discussed accordingly. The results show that the mass fraction of CNTs has an optimum value to the effective absorption ratio of the binary nanofluid, and the effective absorption ratio increases with the initial concentration of ammonia increasing. [Copyright &y& Elsevier]

Succession occurs on a large part of German salt marshes following abandonment or reduction of grazing. Its speed and effect on the biodiversity of salt marshes has been discussed in the literature. Permanent plot studies show site-dependent differences in successional outcome. If grazing is to be continued, there is uncertainty about the stocking rates that are optimal for the conservation of plant diversity. We present an eight year permanent plot study with different grazing treatments on a high salt marsh at the marsh island of Hallig Langeness, Germany, which is enclosed by a summer dike. The study site is owned by WWF. Successional outcomes on the permanent plots depend on grazing intensity and depth of the groundwater table which is correlated with soil salinity. Intermediate stocking rates support a mixture of halophytes and glycophytes, the relative proportion of which depends on the depth of the groundwater table. Cattle grazing at stocking rates of 0.6 livestock units per ha were found to be optimal for plant diversity conservation. At sites with deeper groundwater tables and no grazing, dominant Elymus spp. stands develop and diversity is strongly reduced. If the groundwater table is high, succession following grazing abandonment is retarded and small halophytes prevail. [ABSTRACT FROM AUTHOR]

We studied the effects of predatory crayfish (Pacifastacus leniusculus), the non-lethal effects of fish chemical cues (Oncorhynchus mykiss), and the combined effects of crayfish and fish chemical cues on the performance of tadpoles of two co-existing anuran species, Rana temporaria and Bufo bufo, in experimental pools. We also examined grazing effects on periphyton, the main food source for the tadpoles. Crayfish significantly reduced tadpole survival, particularly by feeding on Bufo. Rana benefited from reduced numbers of competitors, resulting from crayfish predation, by increased growth rate, whereas the growth rate of Bufo was unaffected by crayfish. The proportion of Rana in refuges (in relation to the number of survivors at the end of the experiment) was unaffected by crayfish, whereas proportionally more Bufo stayed in refuges in the presence of crayfish, relative to controls. Fish cues had no effect on tadpole survival of either species. During the entire larval period, Rana responded to fish cues by increasing the use of refuges relative to controls, whereas Bufo did not show any significant behavioral response to fish cues. In accordance with these observations, the proportion of Rana in refuges at the end of the experiment was high in the presence of fish cues, whereas the use of refuges by Bufo was not affected by fish cues. Predatory crayfish and fish chemical cues had additive effects on tadpole survival, growth and refuge use. Tadpoles in all treatments reduced periphyton biomass. Both crayfish and fish cues had positive indirect effects on periphyton biomass. The positive indirect effect of fish cues on periphyton was likely an effect of reduced grazing from Rana. Thus lethal, as well as non-lethal, predator effects on prey populations can influence lower trophic levels. [ABSTRACT FROM AUTHOR]

In the pure stand of tropical seagrass, Syringodium isoetifolium, in a small oceanic island, Fiji, grazing effects of the seagrass-associated gammarid, Ampithoe sp., on seagrass and epiphytes were assessed in October 1989, November 1991, November 1992. Density of the gammarid was estimated with two methods, mesh bag method and tuft method. During the three years surveyed the density of the gammarid increased remarkably from 1989 to 1991, with heavy epiphytism. Gut contents of the gammarid were examined. Grazing rates on seagrass leaf with and without epiphytic blue-green algae were measured in a bottle experiment. Litter bag experiments were conducted using different mesh sizes each containing seagrass only and seagrass and gammarids. The seagrass leaf biomass in the litter bag reduced abruptly in both bags. After one week, 78-86% of seagrass biomass disappeared from the bags. Enhancement of decomposition of seagrass leaf by the gammarid grazing was observed. Oxygen consumption and ammonium excretion rates were measured simultaneously in bottle experiments. Carbon budget in the seagrass bed was estimated as follows: 0.9 gC m day in seagrass growth, gammarid grazing was about a half of it and further assimilated a half of it, about 0.1 gC m day, and more than half of it become CO by respiration. Grazing effects on epiphyte and seagrass growth and production were discussed through the carbon budget and indirect interactions between seagrass, epiphytes and associated gammarids to explain the temporal change of seagrass and epiphyte dynamics. [ABSTRACT FROM AUTHOR]

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In 1978 after about 100 years of absence, 15 Svalbard reindeer, Rangifer tarandus platyrhynchus were reintroduced to Brøggerhalvøya, a peninsula on the north-western coast of Svalbard. This stock had increased to about 200 animals in 1989. Studies of reindeer grazing behaviour were carried out in 1979-1980 and 1988¬1989. Highly prefered lichen species such as Cetraria nivalis had almost completely disappeared by 1989, whereas a less prefered species, Cetraria delisei, was still abundant. Year round dietary intake of grasses, lichens and herbs e.g. Oxyria digyna, had decreased by 1989, whereas that of mosses had increased. Essentially reindeer showed a more opportunistic grazing behaviour with more balanced utilization of all types of plant associations in 1989. The grazing behaviour of the reindeer on Brøggerhalvøya is therefore similar to that observed for Svalbard reindeer in general.

Temperature is an important controlling factor in the growth activity of all microorganisms. Aerobic anoxygenic phototrophic (AAP) bacteria actively grow in the ocean and are known as one of the main driving forces in organic matter cycling in surface seawater environments. Whether temperature change affects AAP bacteria activity from an ecological viewpoint remains an open question. To date, no known studies have reported the effect of temperature change on AAP bacteria growth in the ocean. We here show that the growth rate of AAP bacteria exceeded that of other bacterial types at high water temperatures in the absence of grazers. The slope of the regression line of the net growth rate of AAP bacteria as a function of water temperature was the same as that for non-AAP bacteria at all temperatures (10, 20, and 30°C); however, when grazers were eliminated, it was 4.7 times higher than that of non-AAP bacteria. This result suggests that AAP bacteria are more responsive to water temperature increases than other bacteria and that AAP bacteria might become more dominant than other bacteria under elevated water temperatures., (© 2018 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

In southern France, the natural invasion by Quercus humilis of calcareous grassland takes place in a mosaic of herbaceous and scrubby patches. We hypothesized that the presence of the shrubs Buxus sempervirens and Juniperus comrnunis alter the rate and the pathway of the succession by facilitating the regeneration of Q. humilis. To infer the process of facilitation at a large scale, the spatial distribution ofQ. humilis was studied in relation to acorn sources and the type of plant cover in grazed and ungrazed sites. Abundant recruitment up to 80 m from the wood margins and from isolated oak trees in grassland shows that acorns are dispersed effectively. At the three study sites,the density of Q. humilis individuals was higher under shrubs than in grassland, suggesting that facilitation may occur. This density difference was much higher in the grazed sites than in the ungrazed site. Moreover, before grazing by livestock, the distribution of first-year seedlings is independent of vegetation cover. Thus, shrubs improveQ. humilis regeneration by protecting individuals from grazing. The high density of individuals at the northern edge of shrubs suggests that a second facilitation mechanism may exist, probably related to improved germination conditions. Facilitation by shrubs appears to be very important for Q. humilis dynamics. [ABSTRACT FROM AUTHOR]

Asiatic wild asses, Equus hemionus, were driven to extinction in Israel in the early 20th century. In 1983, a herd of these animals was re-introduced to the wild in Makhtesh Ramon, a large erosion cirque inthe central Negev desert, Israel. The population has grown steadily ever since and now numbers some 100 animals. In order to determine whether the wild asses are having a significant impact on the vegetation, we have monitored the plant communities in Makhtesh Ramon since 1992, using McAuliffe's log-series survey method. Our study involves 11pairs of plots along the length of the altitudinal gradient in Makhtesh Ramon. The altitudinal gradient results in a rainfall gradient from an average of 95 mm rain per year to an average of about 40 mm peryear. Each pair of plots consists of: (I) an unfenced plot, and (2) a fenced plot that excludes wild asses but not the other large mammalian herbivore, the dorcas gazelle Gazella dorcas. The wild asses havenot had a significant impact on vegetation cover, species richness, diversity or dominance. Three plant species showed significant increases in percentage cover in fenced plots, while one species showed a significant increase in percentage cover in unfenced plots. Furthermore, eight plant species invaded fenced plots, three species invaded unfenced plots and one species disappeared from unfenced plots during the study. Using Detrended Correspondence Analysis, we found that the major differences among plots are due to position along the altitudinal gradient. The Detrended Correspondence Analyses indicated that thewild asses have had no significant effect on vegetation community structure. [ABSTRACT FROM AUTHOR]