Sedge Meadow Research Articles

Phosphorus Interactions with Iron in Undisturbed and Disturbed Arctic Tundra Ecosystems.

Phosphorus (P) limitation often constrains biological processes in Arctic tundra ecosystems. Although adsorption to soil minerals may limit P bioavailability and export from soils into aquatic systems, the contribution of mineral phases to P retention in Arctic tundra is poorly understood. Our objective was to use X-ray absorption spectroscopy to characterize P speciation and associations with soil minerals along hillslope toposequences and in undisturbed and disturbed low-lying wet sedge tundra on the North Slope, AK. Biogenic mats comprised of short-range ordered iron (Fe) oxyhydroxides were prevalent in undisturbed wet sedge meadows. Upland soils and pond sediments impacted by gravel mining or thermokarst lacked biogenic Fe mats and were comparatively iron poor. Phosphorus was primarily contained in organic compounds in hillslope soils but associated with Fe(III) oxyhydroxides in undisturbed wet sedge meadows and calcium (Ca) in disturbed pond sediments. We infer that phosphate mobilized through organic decomposition binds to Fe(III) oxyhydroxides in wet sedge, but these associations are disrupted by physical disturbance that removes Fe mats. Increasing disturbances of the Arctic tundra may continue to alter the mineralogical composition of soils at terrestrial-aquatic interfaces and binding mechanisms that could inhibit or promote transport of bioavailable P from soils to aquatic ecosystems.

Vegetation types and flood water level are dominant factors controlling the carbon sequestration potential in Dongting Lake floodplain, China

Wetlands are important carbon sinks. However, the carbon sequestration potential of flooded wetlands may be weakened owing to water regime changes induced by anthropogenic disturbances. Using the eddy covariance technique, this study quantified the effects of the water level and vegetation types on the net ecosystem CO2 exchange (NEE), gross primary production (GPP), and ecosystem respiration (Reco) from a reed marsh (Miscanthus sacchariflorus) and a sedge meadow (Carex spp.) in the Dongting Lake floodplain from 2014 to 2016. Our results indicated that the sedge meadow (−89.49 to −186.47 g C m−2 y−1) and reed marsh (−246.12 to −513.94 g C m−2 y−1) were carbon sinks on the interannual timescale. However, the sedge meadow changed from a carbon sink to a carbon source during the flooding season. The effect of flooding on the carbon sink function in the reed marsh was dependent on the water level. The carbon sink function of the reed marsh was enhanced by moderate flooding (water level under 30.5 m in Chenglingji) owing to the inhibition of Reco, but was weakened by extremely high-water levels (over 33 m in Chenglingji) during the flooding season. Seasonal variations in NEE, GPP, and Reco were closely related to photosynthetic photon flux density, soil water content, water level, soil temperature, and air temperature. We can conclude that the increase in reed area combined with the decrease in flooding days in the sedge meadow can potentially enhance the carbon sink function of the Dongting Lake floodplain.

Long-Term Stability of Harvest Mouse Population

The Eurasian harvest mouse (Micromys minutus) is a tiny rodent of the Palearctic and Indomalayan regions, with a distinct regional species status in Europe and irregularly varying local numbers. We analysed the population of M. minutus in Lithuania (Northern Europe) based on trapping data from 1975 to 2022 and owl pellet data from 1986 to 2009. Based on both datasets, the proportion of this species in the small mammal community was similar, 1.13% and 0.62%, respectively. The proportions have remained stable across all decades. Relative abundance was 1.19 ± 0.19 individuals per 1000 trap days, stable over the long term and across the country. Irregular fluctuations in abundance were observed in some of the sites surveyed. The highest average RA was recorded in open sedge habitats, meadows and marshes. The absolute highest RA was 88 individuals per 1000 trap days in floodplain meadows after a major flood. Although the negative impact of habitat anthropogenisation has been confirmed, M. minutus does not require special conservation measures in Lithuania.

Vegetation communities and summer net ecosystem CO2 exchange on western Axel Heiberg Island, Canadian High Arctic

Climate change is expected to result in the Arctic transitioning from a carbon sink to a carbon source environment, with models predicting half of the carbon stock of the upper 3 m soil layer to be released by the year 2300 (van Huissteden and Dolman 2012). However, uncertainty in latitudinal warming and changes in Arctic ecosystem functions, such as gross carbon ecosystem exchange (GEE), are poorly understood, in part a reflection of a high variability in vascular plant community diversity that is dependent upon and sensitive to physiographic controls, such as soil moisture, topography, and seasonal active layer depth (Walker et al. 2005). This heterogeneity complicates assessments of carbon fluxes on a landscape scale and how they will change in the future (Shaver et al. 2007), especially given their sensitivity to local changes in climate, such as warming and higher rates of rainfall (Bintanja 2018, Bintanja and Andry 2017). As part of the creation of a long-term ecological and environmental monitoring program at the McGill Arctic Research Station at Expedition Fiord, western Axel Heiberg Island, field-based studies in 2021-2022 of plant surveys and summer net ecosystem CO2 exchange monitoring were undertaken to: define the major vegetation communities; quantify and investigate CO2 fluxes with chambers and their analogous biophysical variables; and upscale plot level CO2 measurements to the landscape scale using high spatial resolution remote sensing data. define the major vegetation communities; quantify and investigate CO2 fluxes with chambers and their analogous biophysical variables; and upscale plot level CO2 measurements to the landscape scale using high spatial resolution remote sensing data. The Expedition Fiord area is recognized as a polar oasis, with high plant species richness existing within an environment of heterogeneous physiography. At the moment, five vegetation communities have been identified (xeric dwarf shrub barren, xeric-mesic dwarf shub barren, mesic dwarf shrub tundra, cassiope heath, and sedge meadow) that varied as a function of species diversity, percent cover, soil moisture, and net ecosystem carbon exchange. Barren vegetation communities having stronger respiration fluxes (i.e., carbon source environments) while more vegetated communities have stronger photosynthesis fluxes (i.e., carbon sink environments). Landcover classification revealed with high accuracy (79.3%) that barren ground and barren vegetation communities cover a much larger area compared to wetter habitats. Upscaling summer season measured carbon fluxes based on the landcover map revealed that Expedition Fiord is a carbon source environment, with an average efflux of +94.6 g CO2/day. Ongoing work focuses on the expansion of carbon flux and subsurface monitoring locations, as well as studies of soil carbon and microbial diversity across the different land cover classifications, which will help to better resolve how soil microorganisms, plant detritus, labile organic carbon, soil moisture, slope, aspect, and bedrock geology influence CO2 fluxes throughout the summer season in this high Arctic setting.

Drivers of soil nitrogen availability and carbon exchange processes in a High Arctic wetland

Increased soil nutrient availability, and associated increases in vegetation productivity, could create a negative feedback between Arctic ecosystems and the climate system, thereby reducing the contribution of Arctic ecosystems to future climate change. To predict whether this feedback will develop, it is important to understand the environmental controls over nutrient cycling in High Arctic ecosystems and their impact on carbon cycling processes. Here, we examined the environmental controls over soil nitrogen availability in a High Arctic wet sedge meadow and how abiotic factors and soil nitrogen influenced carbon dioxide exchange processes. The importance of environmental variables was consistent over the 3 years, but the magnitudes of their effect varied depending on climate conditions. Ammonium availability was higher in warmer years and wetter conditions, while drier areas within the wetland had higher nitrate availability. Carbon uptake was driven by soil moisture, active layer depth, and variability between sampling sites and years ( R2 = 0.753), while ecosystem respiration was influenced by nitrogen availability, soil temperature, active layer depth, and sampling year ( R2 = 0.848). Considered together, the future carbon dioxide source or sink potential of high latitude wetlands will largely depend on climate-induced changes in moisture and subsequent impacts on nutrient availability.

Impact of plateau pika burrowing activity on the grass/sedge ratio in alpine sedge meadows in China.

Burrowing activities of plateau pikas cause widespread bare patches in alpine meadows on the Qinghai-Tibet Plateau, affecting the plant community composition and forage production. However, it is not clear how these bare patches influence the main forage composition in alpine meadows. Therefore, we investigated the plant communities in bare patches (BP) and neighboring control plots (CK) in alpine meadows in Maqu county in the Gannan region of China. Our results showed that plant communities in the CK plots differed from those in the BP plots. The sedge cover, number of sedge species and number of grass species were all significantly higher in the CK plots compared to the BP plots. However, grass cover and its dry weight were significantly higher in the BP plots. Grass cover and the grass dry weight in the BP plots were 1.859 times and 1.802 times higher than that in the CK plots across the five sites, respectively. Grasses also had a significantly higher cover and dry weight than sedge in the BP plots, grass cover was 66.5 times higher than the sedge cover, and the grass dry weight was 68.242 times that of the sedge dry weight. Therefore, bare patches resulting from plateau pika burrowing activity significantly increase the grass/sedge ratio in alpine meadows. A potential explanation is that grasses have a stronger reproductive potential than sedges in bare soil. This has implications for pasture yields since grasses have a higher biomass per unit area compared to sedges in alpine meadows.

Brown bear–sea otter interactions along the Katmai coast: terrestrial and nearshore communities linked by predation

AbstractSea otters were extirpated throughout much of their range by the maritime fur trade in the 18th and 19th centuries, including the coast of Katmai National Park and Preserve in southcentral Alaska. Brown bears are an important component of the Katmai ecosystem where they are the focus of a thriving ecotourism bear-viewing industry as they forage in sedge meadows and dig clams in the extensive tidal flats that exist there. Sea otters began reoccupying Katmai in the 1970s where their use of intertidal clam resources overlapped that of brown bears. By 2008, the Katmai sea otter population had grown to an estimated 7,000 animals and was likely near carrying capacity; however, in 2006–2015, the age-at-death distribution (AADD) of sea otter carcasses collected at Katmai included a higher-than-expected proportion of prime-age animals compared to most other sea otter populations in Alaska. The unusual AADD warranted scientific investigation, particularly because the Katmai population is part of the Threatened southwest sea otter stock. Brown bears in Katmai are known to prey on marine mammals and sea otters, but depredation rates are unknown; thus, we investigated carnivore predation, especially by brown bears, as a potential explanation for abnormally high prime-age otter mortality. We installed camera traps at two island-based marine mammal haulout sites within Katmai to gather direct evidence that brown bears prey on seals and sea otters. Over a period of two summers, we gathered photo evidence of brown bears making 22 attempts to prey on sea otters of which nine (41%) were successful and 12 attempts to prey on harbor seals of which one (8%) was successful. We also developed a population model based on the AADD to determine if the living population is declining, as suggested by the high proportion of prime-age animals in the AADD. We found that the population trend predicted by the modeled AADDs was contradictory to aerial population surveys that indicated the population was not in steep decline but was consistent with otter predation. Future work should focus on the direct and indirect effects these top-level predators have on each other and the coastal community that connects them.

Effects of Waterbird Herbivory on Dominant Perennial Herb Carex thunbergii in Shengjin Lake

Abundant food resources in riparian zones provide efficient foraging sites for waterbirds. Herbivory is a key ecosystem process that has widely recognized effects on primary production and vegetation structure and composition. However, there is limited understanding of impacts of waterbird herbivory on riparian zone vegetation. In this study, a bird exclosure experiment with five levels of foraging intensities (no foraging, very little foraging, light foraging, moderate foraging and heavy foraging) was set up in Shengjin Lake to study the effects of waterbird foraging on the community structure of sedge meadows and individual traits of the dominant plant Carex thunbergii. Foraging intensity had little effect on community structure. The dry mass of C. thunbergii decreased with the increasing foraging time. Waterbird foraging reduced leaf dry mass under heavy foraging by 27.7% and root dry mass by 45.6% compared to CK (no foraging). Waterbird foraging increased allocation to shoot growth but had a weak effect on elemental allocation of C. thunbergii. The foraging intensity significantly affected the morphological traits of C. thunbergii. The results of structural equation modeling showed that RSR (root: shoot ratio represents the ratio of dry mass) and RL (root length) are key traits in driving the dry mass decline in the presence of bird foraging. This study may contribute to a better understanding of the adaptability of perennial herb plants to waterbird foraging and maintain the healthy development of wetland ecosystems.

Estimating Long-Term Average Carbon Emissions from Fires in Non-Forest Ecosystems in the Temperate Belt

Research into pyrogenic carbon emissions in the temperate belt of the Russian Federation has traditionally focused on the impact of forest fires. Nevertheless, ecosystems in which wildfires also make a significant contribution to anthropogenic CO2 emissions are poorly studied. We evaluated the carbon emissions of fires in the non-forest ecosystems of the Middle Amur Lowland, in the Khabarovsk Territory of the Russian Federation. Our study is based on long-term Earth remote sensing data of medium spatial resolution (Landsat 5, 7, and 8) and expeditionary studies (2018–2021). The assessment of carbon directly emitted from wildfires in meadow and meadow–mire temperate ecosystems in the Middle Amur lowland shows that specific emissions from such ecosystems vary, from 1.09 t/ha in dwarf shrub–sphagnum and sphagnum–ledum and sedge–reed fens to 6.01 t/ha in reed–forb, forb, reed, and sedge meadows. Meanwhile, carbon emissions specifically from fires in meadow and meadow–mire ecosystems are less significant—often an order of magnitude less than carbon emissions from forest fires (which reach 37 tC/ha). However, due to their high frequency and the large areas of land burned annually, the total carbon emissions from such fires are comparable to annual emissions from fires in forested areas. The results obtained show that the inadequacy of the methods used in the automatic mapping of burns leads to a significant underestimation of the area of grassland fires and carbon emissions from non-forest fires.

Evolution of vegetation in the Utinoe Lake basin (the Russian Far East) during the Middle-Late Holocene

Abstract. Evolution of vegetation in the Utinoe Lake basin was studied. Periodicity of vegetation changes in its basin were reconstructed by the palynological data. The Middle Holocene stage of the vegetation evolution proceeded in the conditions of general planetary increase in average annual temperatures, accompanied by flooding of lowland plains by the Sea of Japan. Composition of the polydominant forests on the ridges during the Middle-Late Holocene was more rich what the present time were formed. Vegetation of the foothill plains was represented with sedge and mixed meadows. The Late Holocene stage was characterized by a decrease in average annual temperatures and series of climatic changes. Its beginning was marked by the cooling, during which the coastal lowlands were freed from sea waters. Climate deterioration caused expansion of dark coniferous and small-leaved plants in the Utinoe Lake basin, as well as reduction of polydominant forests. On the foothills near the coast of the Peter the Great Bay sedge meadows were developed, sometimes there were thickets of Betula sect. Nanae and sphagnum swamps. At the end of the Late Holocene the warming occurred again. On the mountain frame of the Utinoe Lake basin, the vegetation formations with the dominance Q. mongolica, Q. dentata, A. holophylla, P.koraiensis with the presence of birches began to dominate. The dissemination of Pinus densiflora, Ulmus, Carpinus cordata and Acer has increased. On the lowlands the sedge-reed meadows with different grass dominated.

Seed persistence of three species, Carex stricta, Carex hystericina and Phalaris arundinacea, in a restored wetland

Seed persistence and longevity is poorly documented for wetland plants, despite the value of this knowledge for restoration. Seed persistence is particularly important information for sedge meadows (i.e., seasonally ponded freshwater wetlands dominated by Carex spp.), which often fail to recolonize without planting and are rapidly invaded by reed canary grass (Phalaris arundinacea L.). We conducted a 17-year seed burial study along a hydrological gradient in a Minnesota wetland to assess seed persistence of P. arundinacea and two common species of sedge meadows, bottlebrush sedge (Carex hystericina Muhl. ex Willd.) and upright sedge (Carex stricta Lam.). Seed samples were placed in capsules designed to prevent seed loss while allowing for environmental influences. Six boxes, each containing 126 seed capsules (3 species x 14 exhumation years x 3 replicates), were buried in wetland soils under three hydrological conditions (regularly, seasonally, or never inundated) along two transects. Seeds were exhumed 1-, 5-, 6-, 9-, and 17-years post-burial and tested for germinability and viability. For C. stricta and P. arundinacea, seed persistence (50% survival, P50) was < 1 year under all hydrologic conditions, while for C. hystericina P50 was 6 yrs where never inundated and > 17 years when seasonally or regularly inundated. Seed longevity was < 17 yrs for C. stricta and P. arundinacea in locations never inundated; for other hydrological conditions and for C. hystericina, seed longevity exceeded the duration of the burial experiment. If seed persistence is typically reduced where inundation is brief, sedge meadow wetlands drained and cultivated for many decades are unlikely to have long-buried seed banks to serve as propagule sources for revegetation.

Seed limitation and saline-alkaline stress restrict wetland restoration potential in the Songnen Plain, northeastern China

Inland wetlands have declined dramatically in the past century due to land drainage, agricultural intensification and soil saline-alkalization in China. Soil seed banks can be an important component of ecological restoration of farmed wetlands if seeds of aquatic species can survive cultivation. To explore the response of soil seed bank to farming and accompanied environmental stress, we compared the structure and composition of seed banks between natural sedge meadows and adjacent soybean and paddy fields under two water levels (moist and flooded) and two salinity treatments (non-saline-alkaline and saline-alkaline stress) in the Songnen Plain, China. We found that the species richness and seed density in the natural wetland were significantly higher than the two farmed fields. Carex species that are dominant species in the natural sedge meadows were seldom present in the soil seed banks. Instead, other high productive species (e. g. Echinochloa crusgalli and Typha angustifolia) survived cultivation as seeds in the farmed fields. Redundancy analysis identified that soil pH, soil salt content and soil water content explained most variance in seed bank composition. Saline-alkaline stress restricted the seed germination and establishment of wetland species even if hydrology was restored. This study indicates that seed limitation and saline-alkaline stress of soil together restricted seed germination and natural restoration potential in the Songnen Plain. In addition to hydrological regulation, the active revegetation of tussock sedges, and improvement of soil saltine-alkaline condition are necessary to support regional biodiversity in the inland wetlands.

Successional dynamics of a 35 year old freshwater mitigation wetland in southeastern New Hampshire.

The long-term ecological success of compensatory freshwater wetland projects has come into question based on follow-up monitoring studies over the past few decades. Given that wetland restoration may require many years to decades to converge to desired outcomes, long-term monitoring of successional patterns may increase our ability to fully evaluate success of wetland mitigation projects or guide adaptive management when needed. In Portsmouth, New Hampshire a 4 ha wetland was constructed in an abandoned gravel quarry as off-site compensatory mitigation for impacts to a scrub-shrub swamp associated with property expansion. Building upon prior evaluations from 1992 and 2002, we conducted a floral survey in 2020 to compare results with prior surveys to document vegetation successional trends over time. In addition, we monitored the avian community throughout the growing season as a measure of habitat quality. The plant community mirrored documented successional trends of freshwater wetland restoration projects as native hydrophytes dominated species composition. Plant species composition stabilized as the rate of turnover, the measurement of succession, declined by nearly half after 17 years. Researchers should consider long-term monitoring of specific sites to better understand successional patterns of created wetlands as we documented long time frames required for the development of scrub-shrub swamps, red maple swamps, and sedge meadows. High species richness was attributed to beaver activity, topographic heterogeneity from Carex stricta tussocks, and the seed bank from the application of peat from the original wetland. Habitat heterogeneity of open water, herbaceous cover, and woody vegetation supports a diverse avian community including 11 wetland dependent species. Although the mitigation project has not created the full area of lost scrub-shrub swamp after 35 years, it has developed a structurally complex habitat and diverse avian community that effectively provides the functions and values of the impacted system.

Testing Whether Camera Presence Influences Habitat Specific Predation Pressure on Artificial Shorebird Nests in the Arctic

When monitoring the breeding ecology of birds, the causes and times of nest failure can be difficult to determine. Cameras placed near nests allow for accurate monitoring of nest fate, but their presence may increase the risk of predation by attracting predators, leading to biased results. The relative influence of cameras on nest predation risk may also depend on habitat because predator numbers or behaviour can change in response to the availability or accessibility of nests. We evaluated the impact of camera presence on the predation rate of artificial nests placed within mesic tundra habitats used by Arctic-breeding shorebirds. We deployed 94 artificial nests, half with cameras and half without, during the shorebird-nesting season of 2015 in the East Bay Migratory Bird Sanctuary, Nunavut. Artificial nests were distributed evenly across sedge meadow and supratidal habitats typically used by nesting shorebirds. We used the Cox proportional hazards model to assess differential nest survival in relation to camera presence, habitat type, placement date, and all potential interactions. Artificial nests with cameras did not experience higher predation risk than those without cameras. Predation risk of artificial nests was related to an interaction between habitat type and placement date. Nests deployed in sedge meadows and in supratidal habitats later in the season were subject to a higher risk of predation than those deployed in supratidal habitats early in the season. These differences in predation risk are likely driven by the foraging behaviour of Arctic fox (Vulpes lagopus), a species that accounted for 81% of observed predation events in this study. Arctic fox prey primarily on Arvicoline prey and goose eggs at this site and take shorebird nests opportunistically, perhaps more often later in the season when their preferred prey becomes scarcer. This study demonstrates that, at this site, cameras used for nest monitoring do not influence predation risk. Evaluating the impact of cameras on predation risk is critical prior to their use, as individual study areas may differ in terms of predator species and behaviour.

Application of remote sensing in alpine grasslands cover mapping of western Himalaya, Uttarakhand, India.

Grasslands are the world's most extensive terrestrial ecosystem, which provides a variety of services for humans, such as carbon storage, food production, crop pollination, pest regulation, and are a major feed source for livestock. However, grasslands are today one of the most endangered ecosystems due to land-use change, agricultural intensification, land abandonment, as well as climate change. Grasslands are an integral part of human societies across the globe, which are broadly known as tropical savannah and temperate grasslands. In the Himalayan region, grasslands are found in more than 55% of the area and different climatic conditions lead to different varieties of grasslands like Danthonia grasslands, kobresia sedge meadow, etc. Grasslands deal with the spatial and temporal distribution of heterogeneous landscapes, which support a high diversity of various species. Owing to very rugged terrain and inaccessibility, the information on the extent of alpine grassland and percent grass cover (%) across the meadows is limited. Therefore, the present attempt was made to assess the current status of grassland in the alpine region of Uttarakhand above 3000m asl. LANDSAT-8 (OLI and TIRS sensors) satellite data were used to delineate the grasslands using normalized difference vegetation indices (NDVIs) of the alpine region with the help of over 179 ground truth points out of which 50 points are testing points and 129 points are training points. Grass covers (%) were also assessed in the whole alpine region of Western Himalaya of Uttarakhand which nearly consists of over 75 meadows by using random plots (1 × 1m, total 10 per site) in each meadow. Overall, 89.52% accuracy was achieved based on 50 randomly selected testing points. A total of 4949.25 sq. km area is under the different percentage of grass cover in the alpine region of Uttarakhand, Western Himalaya. Danthonia grasslands below 4000m and Kobresia sedge meadows above 4000m elevation are dominant in the state. In the alpine region, over 1056 sq. km grassland area have less than 10% grass cover indicating higher degraded and cold desert areas and only 565.69 sq. km area have more than 60% grass cover, which is highly favorable for rich biodiversity and grazing.

Experimental warming increases ecosystem respiration by increasing above-ground respiration in alpine meadows of Western Himalaya

Alpine ecosystems in the Himalaya, despite low primary productivity, store considerable amount of organic carbon. However, these ecosystems are highly vulnerable to climate warming which may stimulate ecosystem carbon efflux leading to carbon-loss and positive feedback. We used open-top chambers to understand warming responses of ecosystem respiration (ER) and soil respiration (SR) in two types of alpine meadows viz., herbaceous meadow (HM) and sedge meadow (SM), in the Western Himalaya. Experimental warming increased ER by 33% and 28% at HM and SM, respectively. No significant effect on SR was observed under warming, suggesting that the increase in ER was primarily due to an increase in above-ground respiration. This was supported by the warming-induced increase in above-ground biomass and decrease in SR/ER ratio. Soil temperature was the dominant controlling factor of respiration rates and temperature sensitivity of both ER and SR increased under warming, indicating an increase in contribution from plant respiration. The findings of the study suggest that climate warming by 1.5–2 °C would promote ER via increase in above-ground respiration during the growing season. Moreover, net C uptake in the alpine meadows may increase due to enhanced plant growth and relatively resistant SR under warming.

Biochemical composition and productivity of reindeer pastures in the Arctic tundra subzone of the Republic of Sakha (Yakutia)

Northern domestic reindeer breeding in the Arctic zone of the Republic of Sakha (Yakutia) is a traditional and ethnos-preserving industry of the indigenous peoples of the North living there. Anabarsky national (Dolgan-Evenki) district is a place of compact residence of one of the small peoples of the North – the Dolgans. They have preserved their unique traditional method of keeping and breeding of domestic reindeer. Northern vegetation, especially Arctic vegetation is very vulnerable and tender. The problem of ecological and floristic researches of pasture plants in the North-East of the Republic of Sakha (Yakutia) is one of the most important tasks. Domestic reindeer are kept on natural pasture feed, so the urgent task is the rational exploitation of reindeer pastures, which is based on the study of productivity, changes in plant diversity under the influence of grazing and man-made impacts. These factors of influence on the state of deer pastures (degradation and loss of the main feed of deer-lichens) remain poorly studied at present. The purpose of the researches was to provide scientific justification for the rational use and protection of reindeer pastures, to study the feed supply of natural reindeer pastures in the Arctic tundra subzone of the Anabarsky national (Dolgan-Evenki) district of the Republic of Sakha (Yakutia). The results of researches have shown that the maximum yield has been observed in the camp #2: willow-grass meadow – 38 centner/ha DM and grass meadow – 41,3 centner/ha DM. Herbages 5 camps (herb-cotton-grass meadow, mixed grass-meadow of mossy plants, willow-grass meadow, grass meadow, forb-grass meadow, sedge meadow of mossy plants) reindeer pastures have been characterized by a high nutritional value feed, allowing to develop and strengthen the feed base for the development of reindeer breeding in the subzone of the Arctic tundra of the Sakha Republic (Yakutia).

Floristic and Macroinvertebrate Responses to Different Wetland Restoration Techniques in Southeastern Wisconsin

Assessments of wetland restoration quality, especially comparisons among restoration techniques, are essential to adaptive management, but are rarely reported. We evaluated wetlands in southeastern Wisconsin that were restored using different hydrological techniques along with wetlands in two reference groups: wetlands without hydrological modification and Waterfowl Production Areas. Our objectives were 1) to compare condition of wetlands using indices for plant communities and macroinvertebrates and 2) evaluate provisioning of macroinvertebrates for waterfowl broods as a measure of habitat quality. Overall, floristic quality of sedge meadows and emergent marshes was poor in restored wetlands (weighted mean C-values were 1.55 ± 0.13 (SE) and 1.47 ± 0.25, respectively); however, sedge meadow quality was greater in wetlands without surface modification (weighted mean C-value = 3.43 ± 0.82). On a scale from “excellent” to “very poor”, we classified condition of open water communities as “good” based on the macroinvertebrate index across all restoration categories. Density and abundance of macroinvertebrate taxa preferred by waterfowl broods were similar across restoration categories and indicated that wetland basins provide ample food resources. We recommend that conservation planners and wetland managers state quantifiable, appropriate objectives for restoration ahead of implementation and address conflicting objectives with stakeholders.

Foraging behavior of the Greater White-fronted Goose (Anser albifrons) wintering at Shengjin Lake: diet shifts and habitat use

BackgroundThe habitat use and foraging behaviors of waterbirds are closely related to the distribution and abundance of their food resources. Reductions in food supply can cause waterbirds to shift their habitats and adjust their foraging behaviors to meet their nutritional requirements and increase fitness. Seasonal withdraw of the water levels in the river-connected lakes in the middle and lower Yangtze River floodplain provides abundant food resources for the wintering Greater White-fronted Goose (Anser albifrons). Sedge (Carex) meadows are critical foraging habitats for herbivorous waterbirds in the hydro-fluctuation belt, which changes with hydrological conditions and climate. This study aimed to examine the behavioral responses of the Greater White-fronted Goose to temporal- spatial changes of food availability in the Sedge meadows.MethodsFields surveys were carried out at Shengjin Lake from November 2017 to April 2018. According to the phenology of Shengjin Lake, we divided the wintering season into three periods. The food density, minimum temperature, food items, grass height, and number of foraging geese were surveyed, and samples of the foraging behavior were collected. We analyzed the relationship of the foraging behavior and habitat use relative to the food resources, using correlation and linear regression analyses.ResultsAlong with the temporal-spatial variation and exploitation of food resources, the food abundance and items varied widely among the foraging sites. Over the whole wintering period, the foraging habitat with the highest utilization rate was the meadows, followed by the paddy fields, and then mudflats. Furthermore, the utilization of the meadows showed a bimodal distribution trend, while the paddy fields showed a unimodal trend, and a decreasing trend was seen in the mudflats over the whole wintering period. The results of the generalized linear model showed that the foraging rate was related to the food density and grass height, with a linearly increasing trend during the winter.ConclusionsWith the change of food resources in the three habitats, the habitats used by the Greater White-fronted Geese shifted from meadows in the hydro-fluctuation belt to the paddy fields, and then back to the meadows. The time budget for foraging activities increased correspondingly, and there was an increase in the foraging rate to compensate for food shortages.

Soil seed banks and restoration potential of tussock sedge meadows after farming in Changbai Mountain, China

Vast tracts of the wettest agricultural fields have been abandoned worldwide, hence knowledge of their restoration potential is becoming important. Soil seed banks can be important components of ecological restoration, particularly if the seeds of key structural dominants can survive periods of cultivation. In Changbai Mountain, China, we compared the seed banks and standing vegetation between natural sedge meadows and adjacent paddy fields under drained and flooded conditions. The tussock-forming sedge Carex schmidtii dominated plant communities in the natural sedge meadows. However, this key structural dominant species was not found in the paddy fields. Other important wetland species survived cultivation as seeds (e.g. Cyperus fuscus, Lythrum salicaria and Sagittaria trifolia). Species of various life history types require either drawdown (emergent; e.g. C. schmidtii) or flooding (e.g. Potamogeton pectinatus) for successful germination. This study indicates that the seed banks of farmed sedge meadows could contribute towards the establishment of new wetland vegetation assemblages. Active revegetation of sedge meadow, particularly the native tussock-forming Carex, and changes in environmental conditions are necessary to support the region’s biodiversity.