Vegetation degradation causes reduction in the available biomass, and decline in the vegetative cover. The Sadra watershed which covers the upper reaches of Marharlu basin, in southern Iran, has been chosen for a test hazard assessment of this type of degradation. The different kinds of data for indicators of vegetation degradation were gathered from collecting of field data like percent canopy and biomass and also records and published reports of the governmental offices of Iran. A new model has been developed for assessing the hazard of vegetation degradation using DPSIR (Driving forces, Pressures, State, Impacts and Responses) framework. The approach is based on the use of indicators, which may be direct or indirect, ecological, technical, socioeconomic or cultural causes of environmental hazard. Taking into consideration fourteen indicators of vegetation degradation the model identifies areas with different hazard class. The preparation of hazard maps based on the Geographic Information System (GIS) analysis of these indicators will be helpful for prioritizing the areas to initiate remedial measures. By fixing the thresholds of severity classes of the fourteen indicators, a hazard map for each indicator was first prepared in GIS. The hazard classes were defined on the basis of hazard scores arrived at by assigning the appropriate attributes to the indicators and the final hazard map was prepared by intersecting fourteen hazard maps in five main hazard layers including anthropogenic, natural, current state of hazard, livestock pressure and trend of degradation in the GIS. Results show among the five main hazard maps used in the model, the most main effective indicator in vegetation degradation of the study area is ‘Current State of Hazard’. Also areas under severe hazard class have been found to be widespread (58%) and areas under moderate hazard class have been found (42%) in the Sadra watershed.

An expression of plants response to light availability is their shade tolerance which refers to the capacity of a given plant to tolerate low light levels. Survival in a shaded environment can determine phenotypic consequences at morphological and/or physiological levels and such changes may be crucial to survive in heterogeneous and variable conditions. However, the potential plastic response of a given plant trait may be large but the observed plasticity may be lowered by resource limitations or environmental stress factors. In this context, the aim of this research was to analyze morphological, anatomical and physiological leaf traits variations of Sesleria nitida Ten. growing in different light conditions. In particular, plants growing in open (PO) and shade (PU) conditions were analyzed. The results show a 35% higher specific leaf area (SLA) in PU than in PO due to a 94% larger leaf area (LA). The higher height and width of the central and the major lateral vascular bundle in PO than in PU contribute to a higher net photosynthesis (P_N) in sun than in shade conditions. Moreover, the 33% higher ratio between respiration (R_D) and P_N (R_D/P_N) in PU than in PO highlights the greater proportion of the carbon consumed by R_D in the shade population requiring a greater metabolic effort for growth and maintenance. S. nitida in the shaded environment might be favored by the soil pH being a neutro-basophilous species and the larger soil water content (SWC) and mineral content contributing to maintain a positive carbon balance in this limiting condition. The plasticity analysis for open vs. the understory plants (mean plasticity index = 0.32) highlights the leaf trait variations useful to maintain a positive carbon balance where light availability is the main limiting factor. Knowledge of the capacity of S. nitida to first colonize and then modify its phenotype in response to the shade condition can contribute to a better understanding of its ecology.

Isopyrum thalictroides is classified as an indicator species of the so-called ‘old-growth forests’. It occurs in shady deciduous forests and is a characteristic species of the order Fagetalia silvaticae. In many parts of Europe and Poland, it is classified in Red Lists of endangered species with different threat levels. Studies of an occurrence of I. thalictroides were carried out in the years 2000–2002 and 2010–2012 to examine changes in the abundance and morphological and genetic diversity of populations inhabiting small mid-field forest fragments (populations 2–4) and a compact forest (1 population), all located in east central Poland.

Isopyrum thalictroides cover declined drastically at all isolated sites (from 83 to 93%) whereas the whole species diversity of these phytocenoses increased. By contrast, in the compact forest both, the area occupied by I. thalictroides population and the total community composition only slightly changed over time. When I. thalictroides plants sampled from all studied sites were compared in terms of the biometrical characteristics, populations 3 and 4 were found to be most similar, population 1 was less similar and population 2 was the most different of all populations, probably due to strong anthropogenic pressure.

Electrophoretic analysis of seed and leaf storage proteins of Isopyrum thalictroides obtained from the four sites demonstrated that the populations were quite similar genetically, no matter how distant they were from each another. Population 2 was the most diverse, followed by population 1 whereas populations 3 and 4 were the most similar. A decreasing genetic distance in the I. thalictroides population would lead to inbreeding as seed setting by the plants will be poorer and the seeds will be less viable, which will result in a lower number of plants per a given area.

The decreased gene pool indicates that the population of I. thalictroides is threatened with extinction in this area. Therefore, it is warranted to undertake some conservation measures to protect the species; hence the need arises to monitor it.

Since the contribution of total belowground bud bank and different bud types to community regeneration has rarely been explored, the vegetative offspring recruited from different belowground bud types was investigated in four plant communities along a grassland degradation gradient in northeastern China (Inner Mongolia). This gradient, between 1000 and 1500 m a.s.l., has been caused by overgrazing. It is a Leymus chinensis steppe which occupies about 3.0×10⁵ ha. Recruitment from tiller buds was dominant (>80%) in determining the total vegetative offspring density along the whole grassland degradation gradient. However, the proportional contribution of tiller-ramets to total ramet recruitment was significantly greater (P <0.05) during earlier than later stages of grassland degradation, while that of rhizome-ramets showed an opposite pattern. While the percentage contribution and density of root-derived ramets to total ramet density increased significantly (P <0.05) during the late stages of grassland degradation, those of bulb-ramets kept relatively constant along the whole grassland degradation gradient. The relative contribution of hemicryptophytes [i.e., Achnatherum sibiricum, Cleistogenes squarrosa, Festuca ovina, Koeoleria cristata, Poa annua, Stipa grandis] to total plant species richness decreased, while that of geophytes [i.e., Agropyron cristatum, Carex korshinskyi. Leymus chinensis, Allium anisopodium, A. bidentatum, A. tenuissimum, Astragalus galactites, Cymbaria dahurica, Iris tenuifolin, Potentilla acaulis, P. bifurca, Pulsatilla turczaninovii, Serratula chinensis, Thalictrum aquilegifolium] increased with the increases of grassland degradation. Our results showed that as grassland degradation increased, changes in the proportion of tiller-, rhizome- and root-derived ramets with respect to total ramet density determined in turn changes in the proportion of hemicryptophytes and geophytes in the study plant communities.

Submerged aquatic vegetation (SAV) is often difficult to restore due to their low seedling survival rates. Therefore, we hypothesized that the elodeid macrophytes serve as effective “nursery” areas to promote success for seedlings of other SAV. However, the high density of the elodeid community may inhibit the establishment of other SAV. An experiment was conducted to explore this “nursery effect” as a restoration approach to increase the success of seed restoration. Two elodeid species were pre-planted into mesocosms to create three levels of “nursery beds” i.e., bare, sparse (approx. 100 g m^-2) and dense (approx. 200 g m^-2). Seeds of Vallisneria spiralis were then placed into these beds to test the seed germination and growth of V. spiralis seedlings. After three months, seed germination was lower in the bare treatment than in the sparse and dense treatments. The growth of V. spiralis seedlings was greater in the sparse treatment than in the bare and dense treatments. These results revealed that the established elodeid bed had a positive effect on the seed restoration of V. spiralis but that the restoration efficiency was significantly reduced by the high-density cover of the elodeid community.

Water availability is one of the most important factors limiting photosynthetic assimilation of carbon dioxide and growth of individual plants in terrestrial ecosystems. It is especially important for desert shrubs because the diurnal water availability is particularly sensitive to climate change in arid ecosystems. Water use efficiency (WUE) is an indicator of water availability and is frequently used to assess plant performance in various ecosystems, particularly in arid ecosystems. The WUE of plants has been widely assessed using ecological methods and field measurements; however, these approaches are impractical to obtain numerous near-simultaneous estimates of plant water status at the landscape-scale. Consequently, landscape-scale assessments of plant water status are practically pursued through modeling. In this study, measurement and modeling of the diurnal variations of WUE were conducted for a native dominant desert shrub, Tamarix ramosissima, in its original habitat on the periphery of the Gurbantunggut Desert, China. The diurnal net photosynthesis (A_n), stomatal conductance (g_s), and transpiration (T_r) were measured for each individual using a portable photosynthesis system. A coupled model of stomatal conductance, photosynthesis, and transpiration was applied to simulate the diurnal dynamics of A_n, g_s, T_r, and WUE. The model explained 83, 47, 83, and 55% of the variance in the measured A_n, g_s, T_r, and WUE values, respectively, for this desert ecosystem in which T. ramosissima is sparsely distributed. The results demonstrated that the coupled photosynthesis-stomatal conductance-transpiration model strategy is a promising approach to estimate water availability in desert ecosystems in Central Asia.

In a climax community where all species are sharing relatively similar and stable habitat, there are differences in leaf traits between deciduous trees and shrubs and dominant species and companion species, especially in leaf lifespan (LLs). What are the differences of relationships among leaf traits between deciduous trees and shrubs? What are the mechanisms of this phenomenon? Here, we presented a one-year observation and recorded the LLs followed a modified method in a Quercus aliena var. acuteserrata forest in the north slope of the Qinling Mountains, China. We found that (i) Different species in the same stand performed quite differently in their LLs (P <0.005). Average LLs of shrubs was slightly longer (P = 0.05) than that of deciduous trees. (ii) LLs showed a significant negative correlation with specific leaf area (SLA) and leaf nitrogen content (LNC) (P <0.05) in deciduous trees, however, a significant positive correlation with LNC and leaf carbon content (LCC) (P <0.05) was detected in shrubs. (iii) The comparison of the traits between dominant and companion species in arbor layer and shrub layer showed that there was no significant difference in LLs, LCC and LNC, except SLA in arbor layer. Our study indicated that the amount of light, at the community scale, might be a main factor determining the LLs of wood plants in deciduous forest. The difference between trees and shrubs in relationships among leaf traits suggests that deciduous trees and shrubs may take different strategies to adapt to the environment. SLA is likely to be a marker trait to distinguish dominant and companion species in arbor layer of deciduous broad leaved forest.

Desertification, which affects more than two-thirds of the world's arid and semi-arid regions, is a significant global ecological and environmental problem. There is a strong link between desertification of the drylands and emission of CO₂ from soil and vegetation to the atmosphere. The Horqin Sandy Land is a severely desertified area in China's agro-pastoral ecotone due to its fragile ecology, combined with unsustainable land management. We estimated changes of organic carbon content in the bulk soil (0–5 cm), in the light-fraction of soil organic matter (based on density fractionation), and in the various particle-size fractions in areas with mobile sand dunes after implementing grazing exclusion (12 and 27 years) and tree and shrub planting (22 and 24 years). Carbon stocks in the bulk soil and all soil density and particle-size fractions increased significantly in the exclosure and plantation plots. The average rates of carbon accumulation in the bulk soil in the exclosure and plantation plots were 16.0 and 17.8 g m^-2 y^-1, respectively, versus corresponding values of 2.3 and 7.1 g m^-2 y^-1 for the light fraction, 4.3 and 8.0 g m^-2 y^-1 for the coarse fraction, 5.0 and 3.4 g m^-2 y^-1 for the fine sand, 4.5 and 4.2 g m^-2 y^-1 for the very fine sand, and 1.8 and 1.8 g m^-2 y^-1 for the silt clay fraction. The older the exclosure and plantation, the more carbon accumulated in the bulk soil and in each fraction. The carbon pool exceeded the level in non-desertified grasslands after 27 years of grazing exclosure and 24 years of the shrub plantation. Our results suggest that both grazing exclusion and planting trees and shrubs can restore desertified grassland, creating a high potential for sequestering soil carbon, but that the plantations appeared to accumulate soil carbon faster than the exclosures.

Soil microbes' activity is very important for forming of the nutrient stock and , soil structure, as well as the carbon cycle simulation. This is particularly crucial for deep soil layers. Effect of soil microbes on the rate of accumulation and decomposition of the soil organic carbon (SOC) has been found for different regions. However, it is known still a little on the SOC performance for different decomposition rates and its relation to the microbial activity in the saline-alkali desert ecosystem. Therefore, the main task of our research was investigation of interrelation between the soil organic carbon and microbial carbon (SMC) at different depths in the original saline-alkali Gurbantünggüt Desert. Our results showed in the soil vertical profile, (i) SMC and SOC presented a very significant positive linear correlation (R² = 0.63, P = 0.0003); (ii) SMC exhibited two obvious changed-interfaces - 20 cm and 80 cm, the SMC at depth of 0–20 cm, 20–80 cm and 80–500 cm was 2.24–3.06, 0.19–0.72, and 0.0017–0.0097 mg kg^-1, respectively; (iii) in the depth of 0–20 cm and 20–80 cm, the SMC had highly significant difference (P < 0.0001) and at 20–80 cm and 80–500 cm, significant difference (P = 0.013); (iv) according to the soil division based on the SMC, SOC also had some certain stratification; (v) organic carbon layers can be respectively defined according to different microbial activities as active, inert, and stable organic carbon pool. Therefore, these three kinds of organic carbon pools can be quantitatively measured by analyzing their location at different depths of the soil profile.

The distribution, concentrations and origin of urea were studied in surface and profundal waters of meso-eutrophic and highly eutrophic parts of The Great Mazurian Lake System (GMLS) during spring — autumn period. Urea concentrations varied from 0.25 µM in surface layer to 3.36 µM in profundal zone of studied lakes and were in the range of concentrations noted in other non-polluted freshwater habitats. In the photic zone of lakes of GMLS Urea N made up to 10 % the total DON pool and often exceeded 2-3 times of NH₄ -N concentrations. Pattern of changes in urea concentrations observed during three-years study excludes external urea input and suggests supplementation of lake waters with this compounds by phytoplankton decomposition processes. Generally, urea concentrations were negatively correlated with the trophic state index calculated from “algal” as well as from “bacterial” determinants. However, more detailed analysis showed that the relationships between production and assimilation of urea by various plankton components as well as the ecological role of this compound in meso- and eutrophic lakes could be different.

In stream corridors, driftwood represents mainly a dead vegetation biomass and diverse artificial material relocated along a stream by flooding. Most driftwood can contain empty molluscan shells or a minor proportion of live individuals (i.e. molluscan allocoenoses). Drifted material is important for spreading of fauna and flora. Molluscan allocoenoses can provide valuable information on molluscan fauna of the upstream area. The main objective of the study was to describe changes of the species composition, diversity and similarity in molluscan allocoenoses along the model river ecosystem in relation to land use of partial watersheds. In the years 2010–2011, 23 samples of driftwood were taken at 23 sites along the Hron River (Central Slovakia) from the spring to the mouth. Molluscan allocoenoses were composed of 135 species (95 terrestrial and 40 aquatic). The number of species found at particular sites ranged from 29 to 72 with a mean of 48. We confirmed our hypotheses that similarity in molluscan species composition of driftwood from different sampling sites is related to distance between them, the proportion of woodland species is highest in the upper course of the river with highest forest coverage and, finally, the highest total number of species (gamma diversity) in driftwood is in the most heterogeneous (in terms of land use) middle river section. Whereas alpha and gamma diversity were highest in the middle section, beta diversity was lowest. The molluscan assemblages were most variable within the lower section (the highest beta diversity). The studied river with a length of nearly 280 km appeared to be suitable to allow the changes associated with different land use to be reflected in species composition of molluscs. Changes in molluscan community structure documented by repeated driftwood sampling can reveal the changes in land use within the river watershed. Thus, sampling of driftwood can also be used in landscape ecology research.

Spates of different magnitude in a four order section of the lowland Drzewiczka River (central Poland) downstream from a dam reservoir and a wild-water slalom canoeing track (abbr. WCT) located just below the dam were studied. For over 20 years daily fluctuations enabling the training of canoeists induced a patchy mosaic of the riverbed, with five dominant habitats: pool, stagnant with emergent plants, submersed macrophyte, bank and riffle. Artificial floods, in September 2000, March 2001 and February 2002, were other flow events of this reach, thus the main aim of this paper is to assess the resistance of macroinvertebrates, measured as the relative lack of loss in density after floods.

The three- (September) and five-fold (March) increased discharge in relation to the median affected the riverine environmental variables and caused the entrance into the water column and/or washing away of Ephemeroptera, Trichoptera and Simuliidae. In turn the highest-flow event (February, 16-fold flow increase) induced the instability of all bed patches. Oligochaeta, one of the dominant, inbenthic groups of passive drifters, were dragged along the bottom and then stopped by macrophytes. Meanwhile, chironomids, the second dominant benthic group, showed two kinds of behaviour patterns. Orthocladiinae, organisms prone to drift, were washed away after each flood; consequently the riffle and submersed macrophytes became partly depleted of them. Other midges, inbenthic Chironomini (Chironominae) with worse propensities to drift, were also washed out, except from deeper sediment layers, between the roots of macrophytes and in the bank habitat. Thus the macroinvertebrate assemblages in the Drzewiczka River have adapted to the moderate pulse disturbances, but their response to high flow events depends on the species' traits.

Due to decrease in the area of extensively managed, semi-natural grasslands, that contribute to high biodiversity level preservation, the conversion of highly productive meadows to extensively managed, species-rich grasslands is now regarded as an important task for nature conservation. The aim of this long-term study was to assess the significance of restoration measures for diversity and trophic structure of above-ground insect community. That study challenges some weaknesses of previous studies as it was conducted with the use of suction trap enabling quantitative analyses of the changes in most insect taxa, and in a long time-span (1992–2005) in a set of permanent plots. The study area was located in a subalpine zone in Bavaria, near Laufen (Germany). The restoration process was initiated in 1996 by a cessation of fertilization and reduction of number of mowing to 1–2 per year. The changes in insect density and diversity (number of families) were monitored in ten restored and two reference plots with the aid of a suction trap. The changes in the insect community recorded during 14 years support findings from other studies that response of insect community to restoration process is usually slow on average. The short-term comparison in 2004–2005 between the restored and reference plots show that the first ones were characterized by more diverse (in term of family number) insect communities (as a whole as well as in guilds of predatory and parasitic species). From the other side, the long-term trend analysis shows that since 1998–2000 insect diversity and abundance was declining. Also trophic structure is fluctuating without clearly defined trend. These findings are in line with the results of the analyses of taxonomic composition similarity. They did not support the expectations neither that difference between initial and current taxonomical composition in a restored plot increases in time (mainly because of incoming new species), nor that spatial heterogeneity of insect assemblages should increase. However, spatio-temporal insect interactions between sample plots (located close to each other), linked to high movement ability of many insect taxa, could mask the changes in insect community caused by restoration.

Reproductive performance of gulls depends on a variety of factors, but food abundance and its availability are among the most important. Clutch and egg sizes in gulls are found to be strongly influenced by food availability, thus better reproductive performance in the colony with greater fish availability (near fish ponds) was expected in that study. We compared the reproductive traits (clutch size, volume of eggs in the full clutch, relative volume of the C-egg (the third egg in gull's clutches) and hatching success) of Caspian Gull Larus cachinnans in five inland colonies in Poland located at a gravel pit, a lake, a river and two dam reservoirs. Differences in the clutch size between sites were found, with the lowest at a lake. We found similar clutch volume in all studied colonies. C-eggs were slightly smaller than A- and B- eggs, in all colonies and all study years, but the relative volume of C-egg in colonies located near fish ponds (<10 km) was significantly greater compared to colonies located far away. This may be explained by high fish availability in fishponds in comparison to other habitats. However hatching success (the ratio of the number of hatched chick to the number of eggs laid) was highest in the colony at the lake. This indicates that both inland habitats a gravel pit and a lake offered good food conditions for large gulls when fish ponds are nearby.