The general impact of extra nitrogen on ecological stoichiometry was examined in alpine grasslands on the Tibetan Plateau. Extra nitrogen increased the ratio of nitrogen to phosphorus (N:P ratio) in leaves and aboveground parts of plants by 43.4% and 32.7%, respectively. In contrast, extra nitrogen reduced the ratio of carbon to nitrogen (C:N ratio) in leaves by 30.6%. Extra nitrogen decreased soil C:N ratio by 9.1% in alpine meadows, but increased soil C:N ratio by 3.4% in alpine steppes. Extra urea had a stronger positive impact on aboveground vegetation N:P ratio than did extra ammonium nitrate. Extra urea rather than ammonium nitrate decreased aboveground vegetation C:N ratio and soil C:N ratio. The impact of extra nitrogen on aboveground vegetation N:P ratio was positively correlated with latitude, mean annual temperature and precipitation, nitrogen application rate and accumulated amount, but negatively correlated with elevation, duration and aboveground vegetation N:P ratio of the control plots. The impact of extra nitrogen on leaves N:P ratio was positively correlated with nitrogen application rate and accumulated amount. The impact of extra nitrogen on leaves C:N ratio was positively correlated with latitude, but negatively correlated with mean annual temperature and precipitation, nitrogen application rate, accumulated amount, duration and leaves C:N ratio of the control plots. Therefore, nitrogen enrichment caused by human activities will most likely alter element balance and alpine plants from nitrogen limitation to phosphorus limitation. This effect may weaken with time, and increase with climatic warming, increased precipitation and nitrogen input rate.

Aquatic ecosystems are receivers for various pollutants, for instance, Chromium (Cr, one of the toxic heavy metals) and phosphorus (one of the biggest causes of water eutrophication). Such contaminants have brought serious impact on health and security of aquatic ecosystems. Physiological integration between the integrated ramets of clonal plants can increase their tolerance to environmental stress. It is hypothesized that physiological integration and phosphorus could facilitate the expansion of amphibious clonal plants from soil to Cr-polluted aquatic habitats. This study was conducted to primarily examine how physiological integration and phosphorus affected the effects of Cr on plant growth and population expansion. An amphibious clonal herbaceous plant Alternanthera philoxeroides was used to simulate the spread process by induced stolon connection or disconnection, Cr pollution and different levels of phosphorus in aquatic habitats. We found that Cr pollution deployed to apical ramets directly decreased the growth and photosynthetic parameters of the apical ramets that lacked connections to the basal ramets, but these effects could be mitigated by stolon connections. Cr pollution had no effects on these disconnected basal ramets, but the transmission of Cr from the apical parts via connected stolons negatively affected the growth of the basal ramets. Increasing the phosphorus not only increased the growth but also decreased the levels of Cr that accumulated in the plant tissues and the bioactivity of Cr. These results indicated that increasing the phosphorus could benefit the population expansion and establishment of A. philoxeroides through physiological integration from terrestrial to Cr-polluted aquatic habitats.

Forest soils potentially store a large pool of carbon and phosphorus. A deep understanding of the total carbon and phosphorus stock in forest soils is vital in the assessment of the nutrients dynamics in forest ecosystems. This study examined the effects of elevation, soil depth, and climatic variables, specifically mean annual temperature (MAT) and mean annual precipitation (MAP), on soil carbon and organic phosphorus in Schrenk's spruce (Picea schrenkiana) forest at Tianshan Mountains. Results showed that soil organic carbon (SOC) significantly increased while organic phosphorus decreased with elevation. Interestingly, carbon increased faster with increasing elevation in the alluvial horizon than in the leached horizon, demonstrating the important role of deep soils in carbon sequestration potential. SOC concentration decreased with soil depth, whereas phosphorus concentration initially decreased and then increased. SOC had no significant relationships with MAT and MAP, whereas phosphorus concentration decreased with MAT. Similar to the impacts of MAT and MAP on SOC, these two climatic variables also exerted no significant influence on C:P ratio.

Biological soil crusts (BSCs) have a vital role regarding vegetation and soil development in arid and semi-arid areas in the world, and apparently in Iran, where they comprise more than 85% of the land. In this research, the relationship between BSCs and plant functional groups, considering soil parameters along an arid alluvial fan located in Khorasan Razavi province in northeastern Iran, was examined. The sampling carried out in summer, systematically from apex towards base part of alluvial fan, using a 0.25 m² quadrat over a 5-cm thick soil surface. Surface levels were classified into three categories: apex, middle, and base. At each level, 16 samples were taken; in total 48 samples were collected along the alluvial fan from the apex point to the base district. The results showed a strong relationship between BSCs and the soil surface features, and a weak correlation between the plant functional group and soil parameters. BSCs indicated an ecological evolution from apex to the base geomorphic level by soil development; so that BSCs are more developed on the base of alluvial fan, but their diversity is reduced.

Succession of woody species on bogs is a process limited by high groundwater table. In the case of drainage, this limiting factor becomes suppressed and succession may accelerate. The aim of the study was to assess the development of tree stands on a raised bog influenced by drainage and wild fire and to assess the dynamics of woody species encroachment. The study was conducted in the ‘Brzozowe Bagno koło Czaplinka’ nature reserve in NW Poland, where the originally unforested peat bog was influenced by peat harvesting, drainage and fire over 100 years. The diameter at breast height of tree species and natural regeneration were assessed. Six types of tree stands were distinguished: open bog, bog forest with Pinus sylvestris, early-, mid- and late-successional bog forest with Betula pubescens and pioneer forest with Populus tremula, which occurred in the post-fire sites. After ca 100 years of human activity on an unforested peat bog, dense forest emerged on almost all of the study area. Drainage and wildfire influenced tree stand structure. The course of succession most probably goes from open bog to pine bog forest and early-, mid- and late-successional birch forests. Regeneration of B. pubescens is a crucial phase of woody species succession, because this species creates suitable conditions for growth of late-successional species.

As the main predator and disperser of seeds, rodents play an important role in the process of vegetation regeneration by adopting different foraging and hoarding strategies in forest ecosystems. Infrared automated detection cameras and seed-tagging methods were used to understand the effects of rodents on seeds in natural environments. We chose the dominant species Apodemus peninsulae (Korean field mouse) as the focus of this study, and seeds of the three species Pinus koraiensis, Corylus mandshurica and Quercus mongolica were released and tracked in a temperate forest in northeast China. The results showed that approximately 80% of the seeds were manipulated by A. peninsulae, 15.1% of the seeds were used as food, 20.4% of the seeds were handled after feeding, 41.3% of the seeds were handled during storage, and 23.3% of the seeds remained intact. In addition, A. peninsulae preferred Q. mongolica (85.3%) and P. koraiensis (85.6%) over C. mandshurica (59.2%). The rodents frequently hoarded seeds from every species in many small, close-range, widely dispersed, single scatter-hoarded caches around the seed station. Most caches were dispersed approximately 2–4 m from the seed station. The results indicated that A. peninsulae adopted significant discriminatory processing strategies for predation, consumption, dispersal and hoarding of the different seeds of sympatric species. Seed size, proportion of kernel mass, nutrient content, and hull thickness characteristics affected the scatter-hoarding decision processes.

One hundred and five alpine accentors Prunella collaris (Scopoli, 1786) and ninety four dunnocks Prunella modularis (Linnaeus, 1758) were captured in the West Carpathian Mountains of Slovakia in order to compare the morphology of their Ischnoceran parasites Philopterus emiliae Balát 1985 and Philopterus modularis (Denny, 1842), respectively. In the case of both host species, the largest bodied lice occurred in winter, before the beginning of the host breeding season. Lice collected during the host breeding season were smaller in size than those collected in winter. Lice collected in the autumn, following postnuptial molt were even smaller in size. The largest lice were found on the bodies of host individuals with relatively long wings. The lice Ph. emiliae also differed in shape. In winter, the relative size of the head was large, while in the autumn, the head was proportionately smaller in size, compared to other body regions. Adult lice Ph. modularis also tended to have larger heads in April than in July. Measurements of lice over an eleven year period from the same site yielded differences in shape, but not in size. This study is one of the first assessments of seasonal variation in morphology of lice.

In order to evaluate the ecological health condition of Zhanghe River Watershed, an adapted Benthic Index of Biotic Integrity (B-IBI) was developed. Macro-invertebrates were sampled at 12 monitoring stations which were grouped into two condition categories (reference and impaired stations) according to the level of degradation. A total of 47 benthic macroinvertebrates taxa were identified, in which aquatic insects 33 taxa, Mollusca 8, Annalida 3 and Crustacea 3 taxa. Based on macro-invertebrate assemblages characters of this area, 18 candidate biological metrics in four categories, including taxonomic richness, community composition, pollution tolerance, trophic guild, and value distribution, were chosen. In which, four metrics were excluded because of low values or narrow distribution range. Discriminatory power between reference and impaired stations was analysed using box-plots, and six metrics were excluded because the medians of the box-plot inside the inter quartile range. Of all the rest eight metrics, four were not suitable for B-IBI index system because of their high Pearson correlation (| r | 0.75). Finally, total taxa, percentage of Crustacea and Mollusca, percentage of tolerant taxa and percentage of predators were screened out to form a B-IBI index system. Ratio scoring method for B-IBI index was used to get a uniform score. Evaluation criterion was established based on the 25 percentiles value of reference stations. Assessment results using B-IBI showed 5 of sampling stations were in ‘healthy’ and ‘sub-healthy’ state, 3 were in ‘fair’ state, and 4 were in ‘poor’ or ‘very poor’ state of the whole watershed.