Meadow Area Research Articles

Structure and heterogeneity of habitat determine diet of predators despite prey abundance: Similar response in Long-eared, Short-eared Owls and Common Kestrels

According to one of the theses of optimal foraging theory, main prey species abundance in the hunting area is the main factor determining the diet and habitat choices of birds of prey. However other factors can also be important. The habitat structure influences the predators' diets as well. In this study we examined the influence of habitat structure on diet compositions of three species of birds: Long-eared Owl (Asio otus), Short-eared Owl (A. flammeus) and Common Kestrel (Falco tinnunculus). The study was carried out from 2007 to 2019 in a 48 ​km2 area of the Crane's Homeland Reserve, Moscow Region, Russia. The habitat structures of model species' hunting territories (ratio of different types of landscape elements) were classified in module “Semi-Automatic Classification Plugin” based on the QGIS. A boosted regression tree analysis identified that the share of the main prey species in the diet is primarily determined by the landscape structure of hunting territories. The largest share of Common Vole (Microtus arvalis) in birds' diet was determined by the shrubs area (15% of hunting area), the meadow area (75%), the habitat heterogeneity (70%) and the arable land area (5%). The same predictors determined the largest share of Root Vole (Microtus oeconomus): the shrubs area 25%, the meadow area 70%, and the arable land area 3%. The annual mean abundance of prey species did not determine their importance in the diet of birds of prey. Thus, the main prey abundance in the hunting area is not a determining factor for the formation of diet composition of birds of prey.

Evaluation of soil and water conservation function in the Wugong mountain meadow based on the comprehensive index method

Wugong Mountain meadow landscape is well-known both at home and abroad because of its ornamental value. Our study aimed to comprehensively evaluate the function of soil and water conservation at different altitudes of Wugong Mountain meadow soil. The hydro-physical characteristics, including the soil bulk density, porosity, water content, water holding capacity, and permeability of meadow soil at 1600 m–1900 m altitudes, were analyzed. The results showed that the mountain meadow soil's hydro-physiological characteristics and water conservation function significantly differed with altitude. However, the trend of each index did not follow the same law with altitude change. There was a decrease in bulk density of the soil from 1700 m to 1900 m, but a significant increase in porosity and water-holding capacity. Despite the higher porosity and water holding capacity found at 1600 m than at 1700 m and 1800 m, a similar bulk density was found at 1600 m as 1700 m. In addition, the bulk density in the 0–20 cm layer was lower than that in the 20–40 cm layer, while the porosity and water-holding capacity were higher. A higher sequence of soil water conservation capacity was found in soil layers 0–20 cm depth at 1900, 1600, 1800, and 1700 m; in soil layers 20–40 cm depth, it was at 1900, 1800, 1700, and 1600 m. The study found that the sequence of the comprehensive performance of soil water conservation function was at 1900, 1600, 1800, and 1700 m altitudes in the Wugong mountain meadow area. Our comprehensive study of soil water conservation capacity provides a theoretical basis for the rational use of mountain meadow resources in subtropical regions.

Freeze-thaw erosion mechanism and preventive actions of highway subgrade soil in an alpine meadow on the Qinghai-Tibet Plateau

Freeze-thaw erosion is widely distributed in China, where the difference of natural conditions brings a series of characteristics for different regions. The alpine meadow area of the Qinghai-Tibet Plateau (QTP) has a special climate, geography, and hydrogeology environment, with multiple road frost heaves and frost boiling failures, which seriously threaten the highway constructions in the QTP. This study summarizes the freeze–thaw geology of the southeastern QTP. For the highway constructions in the frozen soil areas, multiple problems such as frost heave, thawing settlement, freeze–thaw weathering, and pavement cracks and highway operation and management issues may rise as a result of the activity of the freeze–thaw geology, which damages the subgrade structure. To prevent the occurrence of possible hazards and reduce hazards and risks, this study discusses a series of countermeasures and suggestions. A case history is referred to, specifically the Budongquan highway in the QTP, where the study section is conducted, to evaluate the effectiveness of the adopted treatment measures. The results show that these treatment measures effectively prevent the surface water from infiltrating into the subgrade in the rainy season, block the migration of groundwater to the upper subgrade during the freezing season, and discharge the water accumulated in the subgrade as soon as possible after thawing. Thus, this study further understanding of the long-term durability and stability of subgrade, and provide useful information for the structure design of the highway subgrade in cold regions.

Physiological effects of γ-aminobutyric acid application on cold tolerance in Medicago ruthenica.

Low temperatures in the seedling stage during early spring limit Medicago ruthenica germination and seedling growth. Elucidating the physiological mechanism of γ-aminobutyric acid (GABA)-regulated cold tolerance in M. ruthenica could provide a reference for alleviating the harmful effects of low temperatures on legumes in alpine meadows. The regulatory effects of GABA on M. ruthenica physiological parameters were explored by simulating the ground temperatures in the alpine meadow area of Tianzhu, China, in early May (2h at 7°C; 6h at 15°C; 4h at 12°C; 2h at 7°C; 10h at 3°C). Our results showed that 15 mmol/l GABA was the optimal spray concentration to promote growth in the aboveground and belowground parts and increase the fresh and dry weights of seedlings. At this concentration, GABA enhanced the activities of catalase, peroxidase, superoxide dismutase, and ascorbate peroxidase; increased the osmotic balance; and inhibited the production of harmful substances in the cells under low-temperature conditions. GABA also regulated the tissue structure of leaves, increased the cell tense ratio, maintained photochemical activity, increased the amount of light energy to the photochemical reaction center, and improved the photosynthetic rate. Furthermore, exogenous GABA application increased the endogenous GABA content by promoting GABA synthesis in the early stages of low-temperature stress but mainly participated in low-temperature stress mitigation via GABA degradation in the late stages. Our results show that GABA can improve the cold tolerance of M. ruthenica by promoting endogenous GABA metabolism, protecting the membrane system, and improving the leaf structure.

‘The public perception of the role, importance, and vulnerability of seagrass. A case study from the Great Barrier Reef’

Seagrass meadows, one of the world′s greatest natural assets, are globally declining due to direct-anthropogenic (e.g., pollution, coastal development, run-off) and climate change (e.g., cyclones, floods, marine heatwaves) threats. One of the primary constraints in seagrass management and restoration is a lack of societal awareness about their role in the marine environment, their importance to human well-being, and their vulnerability. Public perception studies are useful tools to assess communities′ ecological knowledge and attitudes. The Great Barrier Reef World Heritage Area (GBRWHA), famous worldwide for its iconic coral reef, also hosts one of the world′s largest areas of seagrass meadows, which provide many ecosystem services to the associated communities (e.g., nursery habitat, coastal protection, carbon sequestration etc.). However, the perception of seagrasses among coastal communities of the GBRWHA is poorly understood. Through an online survey of marine recreational users, we assessed public awareness of the role seagrasses play, its benefits, and threats to seagrasses in the GBRWHA, in comparison to coral reefs. Our results showed that there is an imbalance in perception of the role and ecosystem services provided by seagrasses and coral reefs among frequent visitors of the GBRWHA. Only 17% of respondents recognized ‘seagrass’ as a habitat of the GBRWHA. Ecosystem services from coral reefs were considered greater than from seagrasses (p < 0.05). Compared to previous studies, a higher percentage of participants believe in climate change (75%). Nevertheless, the general perception is that climate change impact magnitude is higher in coral reefs compared to seagrasses (p < 0.05). Additionally, climate change mitigation, a seagrass-related ecosystem service, was equally attributed to coral reefs and seagrasses (p > 0.05). Willingness-to-pay for coral reef restoration was higher than for seagrass (p < 0.05). For both marine habitats, willingness-to-pay for restoration was higher in younger people and participants with a university degree. Content analysis showed that people believe that marine habitats′ conservation/restoration can be achieved as a collective effort. On the other hand, a lack of trust in government actions was identified as a barrier to willingness-to-pay. These results confirm the need to raise awareness about the importance of seagrasses and of its vulnerability to climate change. To achieve that, we provide two key recommendations: to enhance purposeful experiences through citizen science and to increase effective scientific communication.

Contrasting effects of light and noise pollution interact with natural vegetation remnants: Human-related indicators of the habitat suitability for ungulates in the urban landscape

The features of the urban landscape encouraging large ungulates expansion are not known. However, prevalence and abundance of wild boar Sus scrofa has been steadily increasing over the years, and nowadays the species has become a recognized component of urban wildlife in many parts of its range. The aim of this work was to select habitat and human-related factors that could affect the probability of the species occurrence and constitute the honest indicators of the habitat suitability for this ungulate in the urban landscape. The data on the presence of grubbed patches of ground (an honest indicator of occurrence) were collected on randomly selected sample plots (N = 100) within the city of Kraków (Poland). We found that wild boar used 45% of the sample plots. Whereas the occupied plots were spatially concentrated, the habitat variables increasing the probability of the species occurring in the urban landscape were the presence of large patches of woodland remnants and large areas of semi-natural meadows. However, the study also revealed a negative relationship between the presence of the species and artificial lighting but a positive one with anthropogenic noise pollution. Our results indicate that the urban landscape consists of surrogate habitats for this large mammal but light and noise pollution may have contrasting effects on the species’ occurrence. This indicates that the influence of human-related factors on the attractiveness of natural vegetation remnants for wildlife is more complex than merely a limiting factor. This reveals high potential of light and noise pollution as indicators of the habitat suitability for ungulates in the urban landscape.

Public perceptions of blue carbon in South Korea: Findings from a choice experiment

Blue carbon has been recently recognized worldwide as one of the various carbon reduction measures. There are three types of blue carbon in the South Korean Ocean: salt marsh, seagrass meadow, and tidal flat. This article strives to assess the economic value of blue carbon judged by the public by the use of a choice experiment (CE). Chosen attributes for the CE application were the area of salt marsh, the area of seagrass meadow, and the number of tidal flats. A CE survey of 1000 households was successfully implemented throughout the country. All the estimates for the three attributes and price held statistical significance. The yearly household economic values arising from one unit (1 km2) increase in each attribute were computed to be KRW 202 (USD 0.18), KRW 238 (USD 0.21), and KRW 331 (USD 0.30), respectively. This quantitative information can be used in calculating the economic benefits of a blue carbon restoration project and performing cost-benefits analysis on the project. The results demonstrate that for all three types of blue carbon, the economic benefit of restoring 1 km2 of each blue carbon type was at least five times greater than the cost of restoring it. In other words, the restoration of blue carbon is socially profitable.

Soil Quality Assessment in Tourism-Disturbed Subtropical Mountain Meadow Areas of Wugong Mountain, Central Southeast China.

Meadow soil is a vital ecosystem component and can be influenced by meadow vegetation. Evaluating soil quality in mountain meadows subjected to different levels of tourism disturbance is essential for scientific research, ecological restoration, and sustainable management. This study aimed to evaluate meadow soil quality at different tourism-disturbance levels and attempted to establish a minimum data set (MDS) with compatible indicators for soil quality assessment of subtropical mountain meadows. We analyzed fifteen soil physical, chemical, and biological indicators in control check (CK), light disturbance (LD), medium disturbance (MD), and severe disturbance (SD) meadow areas in Wugong Mountain, west of Jiangxi, China. In addition, a soil quality index (SQI) was determined using the established MDS based on the integrated soil quality index. Average soil permeability, soil pH, available nitrogen (AN), available phosphorus (AP), and number of fungal OTUs were finally introduced into the MDS to evaluate meadow soil quality at different tourism-disturbance levels. The study found that the soil of the Wugong Mountain meadow was acidic, the bulk density was loose, and the nutrient content was rich. Additionally, SQI decreased with increase in tourism-disturbance level. The mean SQI values of the Wugong Mountain meadow areas were: CK, 0.612; LD, 0.493; MD, 0.448; and SD, 0.416. Our results demonstrate that the SQI based on the MDS method could be a valuable tool with which to indicate the soil quality of mountain meadow areas, and the SQI can be regarded as a primary indicator of ecological restoration and sustainable management.

The Occurrence of Tick-Borne Pathogens in Samples Collected from the West Pomeranian Voivodeship

In this work, ticks were collected from the military area of the West Pomeranian Voivodeship in Poland, and the most important pathogens were detected using the real-time PCR method. The ticks were collected in mid-spring (April and May) using the flagging technique. They were collected in five places: on the shoreline of Drawa River and Konotop Lake, as well as in forest and meadow areas near Karwice, Konotop and Oleszno Villages. During the work, only one species of ticks was caught – Ixodes ricinus. All the collected specimens were assessed in terms of their species, sex and developmental stage by zoological specialists. The largest number of specimens was caught in Karwice (35%, n = 666). The highest number of ticks in each test site were nymphs (57%, n = 1106), except at Konotop. The reaction of RT-PCR was tested in 111 pools of ticks. As a result of the PCR reactions (VIASURE Tick-Borne Diseases Real-Time PCR Detection Kit), Rickettsia spp. (n = 70) and Borrelia burgdorferi s. l. (n = 35) were determined to be the most frequently identified pathogens in the tick samples. Other pathogens such as Anaplasma phagocytophilum and Ehrlichia chaffeensis were detected in a smaller number of samples. The results in this paper confirm the epidemiological data collected and analysed prior to now.

A new hope for conserving the disjunct population of the Sierra Madre Sparrow Xenospiza baileyi: population size and new breeding localities in the Sierra Madre Occidental, Mexico

Summary The Sierra Madre Sparrow Xenospiza baileyi is an endangered Mexican endemic and a bunchgrassland specialist with a disjunct range: a relatively larger population in the south-eastern Trans-Mexican Volcanic Belt, and a smaller and poorly studied population in the Sierra Madre Occidental. In the latter, known distribution and abundance consists of four localities with a maximum of 28 individuals recorded in one of them. We surveyed the Sierra Madre Sparrow in 30 sites with suitable habitat, meadows or “bajíos” with bunchgrasses, in the municipalities of Durango, Pueblo Nuevo, San Dimas, and Canatlán in the Sierra Madre Occidental of Durango. We detected a total of 193 individuals in nine (30%) of the sites (392 ha), conducting intensive searches throughout them. Bunchgrasses in confirmed meadows were composed mainly of Muhlenbergia macroura, M. rigida, M. speciosa, M. rigens, and Piptochaetium fimbriatum. Total bunchgrass area within a meadow was a significant positive predictor of the Sierra Madre Sparrow presence, while total meadow area was not a significant predictor of its abundance. Seven of the confirmed localities were previously unknown, and two of them harboured 55% of the observed individuals: Ex Hacienda Coyotes (Pueblo Nuevo) and La Lobera (San Dimas). The estimated population size is at least four times higher than any previous record (28) or suggested (40–50) for the Sierra Madre Occidental and raises an opportunity and a challenge for conserving this genetically distinct population of the Sierra Madre Sparrow in the region.

Soil organic carbon stocks in the high mountain permafrost zone of the semi-arid Central Andes (Cordillera Frontal, Argentina)

This study presents the first detailed soil organic carbon (SOC) inventory for a high mountain permafrost zone in the semi-arid Central Andes of South America. We describe plant cover and soil profiles at 31 sites representing the main land cover and landform types in the Veguitas catchment (Cordillera Frontal, Argentina), which ranges in elevation from c. 3000 to 5500 m. The vegetated area with soil development is largely confined to altitudes of < 3650 m and represents only 8.2% of the total catchment area. Mean SOC 0–100 cm storage for the vegetated portion of the catchment is 3.62 kg C m−2, which is reduced to 0.33 kg C m−2 if we consider negligible SOC stocks in the extensive bare ground and glaciated areas at higher elevations. Hotspots of SOC storage are wet meadow areas, with peat deposits up to 102 cm deep and a maximum observed total SOC storage of 53.07 kg C m−2. These wet meadow areas, however, occupy only 0.11% of the total catchment area and their contribution to mean SOC storage is limited. Among soils at well-drained sites, highest mean SOC 0–100 cm storage is found on backslope positions of moraines that predate the Last Glacial Maximum (6.87 kg C m−2). Only 2% of all SOC stocks in the catchment are found in permafrost terrain and none are located in the permafrost layer itself. The main ecoclimatic control on SOC storage is plant cover, with vegetation limits being sensitive to ambient temperature. Projected increases in temperatures will not remobilize any frozen SOC stocks but will likely result in an upward shift of the upper vegetation belt with soil development creating new areas of phytomass carbon and SOC storage. The area is expected to represent a net C sink and thus a negative feedback on future global warming.

Study and comparison of population density indices of Ixodes ticks of different biotopes of Kyiv and Cherkasy regions

Ixodes ticks play an important role in the spread of various infectious diseases. Representatives of the Ixodes family carry a large number of pathogens. Zoonotic infections, such as tick-borne borreliosis, tick-borne encephalitis, ehrlichiosis, anaplasmosis, etc., are especially dangerous. Areas of distribution of Ixodes ticks are quite diverse: forests, meadows, shrubs, city parks and various types of green spaces in cities. The study of the quantitative and species composition of ticks in natural foci of infectious diseases is an important component of assessing the epizootiological biopotential and forecasting the risks of infectious diseases in certain areas. In the studies, we studied and compared the distribution of Ixodes ticks based on the population density index of Ixodes ricinus and Dermacentor reticulatus in two different habitats: anthropogenically transformed semi-natural forest environment and meadow-type with pastures. The first – the forest area is located in the forest park tract "Golendernya" in Bila Tserkva, Kyiv region. The second – a natural meadow area is located in the Cherkasy region, Lysyansk United Territorial Community (OTG), village Zhabianka. Collection of Ixodes was performed by the usual method on the flag. The population density index is expressed in relation to the number of ticks per 1 m2 of the surveyed area with a correction factor of 1.2. A total of 12,000 m2 of total habitat area was surveyed, 572 specimens of Ixodes ticks were collected, including 393 Ixodes ricinus and Dermacentor reticulatus 179, respectively. 356 Ixodes ticks were collected in the Golendernia tract, of which 339 were Ixodes ricinus and only 17 were Dermacentor reticulatus. Accordingly, in Golendernia tract the population density index of the surveyed area of 6 thousand m2 Ixodes ricinus is 0.07 specimens/m2 (95.9%) and Dermacentor reticulatus – 0.003 specimens/m2 (4.1%). 216 specimens of Ixodes ticks were collected in the natural meadow biotope, of which 162 – Dermacentor reticulatus and 54 – Ixodes ricinus. The population density index of the surveyed area of 6 thousand m2 in the meadow biotope with mites of the species Dermacentor reticulatus is 0.03 specimens/m2 (75.0%), and with mites of the species Ixodes ricinus – 0.01 specimens/m2. (25.0%). Population density indices between Ixodes ricinus and Dermacentor reticulatus have a statistically significant difference (p &lt;0.01) which is due to the types of habitats. Key words: Ixodes tiks, Ixodes ricinus, Dermacentor reticulatus, population density index, habitats.

The impact of invasive Caucasian hogweeds on birds depends on areas of invaded and uninvaded habitats at various scales in Central European uplands

The availability of various habitats increases biodiversity and provides niche opportunities for organisms, although greater habitat diversity may contribute to the spreading of invasive plants. In this study, we aimed to assess the impact of the extent of invasion on bird responses to the availability of their natural habitats. Specifically, we asked whether the Caucasian hogweeds, herbaceous invasive plants spreading in abandoned lands, shape those responses by providing new niche opportunities or limitations and whether these invaders can be tolerated by the bird community. The research was conducted in south-eastern Poland in 2020 on 64 research sites, half of which were located near the Caucasian hogweeds’ invasion. The birds were counted from points within 100 m, while the areas of invaded and uninvaded habitats were measured within 100 and 500 m. The impact of the invaded area was negative for the overall bird abundance and species richness. At the same time, the invasion affected birds differently depending on their nesting/foraging assemblages, the availability of various uninvaded habitats, and the extent of invaded areas. Specifically, the abundance of ground/herb dwellers non-linearly dropped even with small increases of the invaded area suggesting their high sensitivity to invasion. These birds were supported by the agricultural land availability, but only when its area was lower than 1.0 ha and the habitat was fragmented, indicating the value of extensive croplands for ground/herb dwelling species. Ecotone birds benefited from small invaded areas mixed with bushes but suffered when the invaded areas were large. Habitat homogenization by the invader physiognomically similar to shrubs was favoured by bush foragers. Tree foragers preferred forest partitioning near the largest invaded areas. The invaded and uninvaded habitats influenced bird community at a fine scale (i.e. in a 100-m radius), while only crucial areas of meadows, forests and agriculture available in a 500-m radius remained important for the community. This study showed that even a small amount of plant invaders rapidly and negatively affect birds when they grow in open areas and are physiognomically different from these birds’ habitats, while species living in ecotone or trees suffer from severely invaded areas. It suggests the priority of invading weeds’ removal in open areas, regardless of the invaded area, as well as the need to prevent weed development in overgrown areas.

Using satellite imagery to compare land cover and water resources in two counties of the Nebraska Sandhills

The Nebraska Sandhills comprise the most intact grassland habitat in the world and 95% of land use consists of low intensity cattle grazing. Water is a key resource for cattle and for growing hay forage in this semi-arid grassland. Ranchers rely on either naturally occurring wet meadows or center pivot irrigation systems (CPIS) to produce hay. With the possibility of climate change creating more frequent extreme weather events, more flooding events or severe droughts could affect land and water resources in the Sandhills. With potentially more wet/dry extremes in the future, an understanding of the way water resources respond, and the different strategies of landowners, will be important in assessing the overall resilience of the Nebraska Sandhills in the face of a changing climate. We compared two adjacent, similarly sized, counties, Grant and Hooker, in the central Sandhills that differ in the amount of naturally occurring, ground water-fed meadows during the period 2002-2019, spanning wet and dry years. ArcGIS and the USDA’s Cropland Data Layer (known as “CropScape”), an annual, satellite imagery-derived, land cover map, were used to quantify overall landcover, especially the cover of wet meadows and the number of CPIS. In 2016, an average-to-moderate precipitation year, Grant County had approximately 10 times more open water area and 9 times more wet meadow area than Hooker County. In contrast, Hooker County had 19 times more barren ground area and nearly twice as many CPIS as Grant County. Furthermore, in drought years, the amount of barren ground increased in both counties, nearly doubling in Hooker County in 2006, a year when annual precipitation was only 66% of normal precipitation rates. Drought also increased the acreage devoted to irrigated crops, particularly in 2006 in both counties, with nearly two times as many acres in Grant County and nearly five times as many acres in Hooker County. Additionally, open water acreage decreased by nearly 50% following the 2006 drought and wetland cover types increased. This analysis showed that different Sandhill counties have contrasting water resources, with an abundance of naturally occurring wet meadows in Grant County, whereas Hooker County has fewer wet meadows and more CPIS. Furthermore, our analysis suggests that the landscape changes during drought years, with a decline in wet meadows, an increase in barren ground and an increase in CPIS and other irrigated systems for crops. In a changing climate, with potentially more extremes in precipitation, the diversity of strategies exemplified by these two counties will be important to inform adaptative responses. Overall, this research will contribute to a better understanding of the sustainability of land use and the future of groundwater resources in the Nebraska Sandhills.

Assessment of Spatial Temporal Changes of Ecological Environment Quality: A Case Study in Huaibei City, China

Under the short-term economic development goal, the excessive exploitation of natural resources and the destruction of the ecological environment make the ecological environment of Huaibei cities increasingly fragile. This study constructed the Remote Sensing Ecological Index (RSEI) to evaluate the ecological environment change trend and its driving factors in Huaibei City from 2000 to 2020. The barycenter migration model was used to determine the RSEI spatial change trend, and the geographic detector was used to analyze the influencing factors of the RSEI value change. The results showed that: (1) the average RSEI value of Huaibei City generally fluctuates within the range of good and excellent grades. (2) The migration direction of the barycenter of RSEI is similar when the level of RSEI improves or decreases from 2000 to 2020, and the barycenter migration is most severe from 2005 to 2015. (3) The driving factors of RSEI change were population density (0.47) &gt; land use (0.24) &gt; slope (0.14) &gt; precipitation (0.08) &gt; temperature (0.04) &gt; altitude (0.03). All the factors had interaction effects on the RSEI, mainly with nonlinear enhancement. (4) From 2000 to 2010, urban construction encroached on all kinds of land, which was the direct reason for the decline in ecological environment quality. From 2010 to 2020, the surge of water and meadow areas improved the ecological environment quality of Huaibei city. Therefore, reducing the expansion of artificial land, returning farmland to forests and meadows, wetland park construction, and other ecological protection measures are the keys to ensuring the sustainable development of regional social and economic development. This study can provide a reference and scientific basis for sustainable development strategy and ecological protection planning to improve the ecological environment quality of Huaibei City.

The Abundance and Persistence of Temperate and Tropical Seagrasses at Their Edge-of-Range in the Western Atlantic Ocean

Species, including seagrasses, at their range limits are uniquely vulnerable to climate change. In the western Atlantic Ocean, the biogeographic transition zone between temperate and tropical ecosystems is recognized as one of several global hotspots where poleward-flowing western boundary currents are forecast to warm faster than the global average. In this region seagrass ecosystem services are primarily supplied by two species, Zostera marina, a temperate seagrass at its southern range limit and Halodule wrightii, a tropical seagrass at its northern limit. Water temperatures in the study location in Back Sound, North Carolina, USA have gradually increased the length of the stressful summer season for Z. marina (beginning after 3 consecutive days of daily mean water temperatures &amp;gt;23°C, ending after 3 consecutive days &amp;lt;25°C) from 84 days in 1962 to 156 days in 2019. The occurrence of extreme water temperatures also increased resulting in temperatures ≥30°C occurring more frequently in the last decade (2009-2019) than the previous 10 years. Biomass and aerial imagery collected periodically from 1981-2019 indicate that Z. marina biomass remained stable until 2008 but declined to 30-year low levels by 2019. Meadow area estimated from imagery collected during peak Z. marina biomass did not show a significant trend over time; however, lowest meadow area during the time series was recorded in 2019. Despite summer warming, H. wrightii biomass remained steady between 1979-2019 but did not replace Z. marina as the dominant species in the cooler months. We hypothesize that persistence of temperate Z. marina populations under stressful water temperatures is positively influenced by water clarity, life history, and meadow stability, due in part to the consistent presence of tropical H. wrightii maintaining meadow biomass and area. However, temperate species in edge-of-range tropicalized meadows, are still limited by physiological thresholds, and when these limits are exceeded, related declines in meadow biomass and area may not be fully replaced by tropical species immediately. Therefore, while tropicalization of seagrass meadows may result in greater resilience to abiotic stressors in the short-term, declines in biomass and area during the process of tropicalization may have significant impacts on meadow function.

Trends in ANPP Response to Temperature in Wetland Meadows across a Subcontinental Gradient in Patagonia

Due to ongoing global warming, seasonal patterns of aboveground net primary production (ANPP) may be altered by temperature trends. Of particular interest is the seasonal association between ANPP and temperature at the beginning of the growing season (the period encompassing minimum to maximum ANPP), where two contrasting mechanisms are in tension. On the one hand, the restrictions exerted by low temperatures in winter may be relaxed, increasing the slope of seasonal association between ANPP and temperature over the years. On the other hand, increases in temperature may increase water demand, reducing the slope over time. Across 543 wetland meadow areas in Patagonia, we estimated ANPP and obtained temperature records on a monthly basis from 2001 to 2019. The seasonal association between ANPP and temperature, tested through linear regression, was statistically significant in 96% of the cases (9921/10317 (543 wetland areas × 19 growing seasons)). The fitted linear models explained, on average, 84% of ANPP seasonal (June–December) variations. Through regression trees, we found out that the two tested mechanisms, the relaxation of temperature restriction and the increase in water demand, showed clear spatial patterns. The relaxation due to temperature increase took place at higher latitudes, but the water-limiting mechanism increased over mid-latitude areas.

Effects of climate change, coal mining and grazing on vegetation dynamics in the mountain permafrost regions

The ecological environment in alpine regions is fragile and sensitive to land-use and land-cover (LULC) change and climate warming. However, there are limited studies on the response of LULC and vegetation activity to climate change and human interference in mountainous permafrost regions. Based on in-situ meteorological and multi-source remote sensing data, we performed time trend and partial correlation analyses to investigate the spatial and temporal variation of LULC, landscape pattern, and vegetation growth under the impact of climate change and human activities in the source region of the Datong River from 2000 to 2019. Our results showed that the alpine desert area decreased significantly at a rate of −13.1 km2 yr−1 (p < 0.05), while the alpine meadow area increased at a rate of 8.3 km2 yr−1 (p < 0.1). Mining and road areas showed a significant increasing trend at a rate of 3.2 km2 yr−1 and 1.2 km2 yr−1, respectively. The increasing alpine meadow and mining areas were mainly derived from alpine deserts and alpine wetlands, respectively. The number of alpine wetland patches increased significantly along with a significant decrease in the landscape shape index of the rivers. Vegetation growth, as indicated by the enhanced vegetation index (EVI) was positively correlated with temperature but negatively correlated with precipitation and solar radiation in 59.6%, 52.3%, and 56.5% of the vegetated areas, respectively (p < 0.05). Temperature was the dominant climate factor controlling vegetation dynamics, and the recent warming hiatus resulted in a significant increase in EVI for alpine deserts, but no significant changes in EVI for alpine wetlands and alpine meadows. Increasing risk of negative impacts from human activities, including mineral exploration and grazing, on vegetation distribution and growth was observed. This study provides clear evidence of the upward invasion of alpine meadows into alpine desert areas under warm and humid climatic conditions. As climate warming intensifies, alpine meadow expansion may be impeded by extreme precipitation and permafrost thawing.

The Volchia Griva mineral oasis as unique locus for research of the mammoth fauna and the late Pleistocene environment in Northern Eurasia

AbstractThis paper describes the results of research at Volchia Griva, the largest site in Asia containing mammoth fauna in situ. It is situated in the south of the West Siberian Plain in the Baraba forest-steppe zone, and occupies an area of several hectares. Analysis of sediments and taphonomy of the site allows us to suggest that thousands of megafaunal remains were buried here in mud pits and erosional depressions. The favorable geochemical landscape of Volchia Griva attracted animals during periods of mineral starvation. This is reflected in the high mortality in two intervals, ca. 20–18 14C ka BP and ca. 17–11 14C ka BP. The results of palynological analysis of samples from the upper part of the Volchia Griva section made it possible to reconstruct the history of landscape changes of the Baraba Lowland during the MIS 2. Forb-mesophytic meadows were common at the beginning of this period, with taiga type forests. At ca. 20 14C ka BP, an abrupt and significant aridization of the climate occurred, which led to the degradation of forests. The mammoth steppe was widely developed, dominated by forb-grass association and with areas of alkali meadows and soils. Such conditions existed probably until the mid-Holocene.

Extent of Sedge-Grass Meadow in a Lake Michigan Drowned River Mouth Wetland Dictated by Topography and Lake Level

Water-level fluctuations are critical in maintaining diversity of plant communities in Great Lakes wetlands. Sedge-grass meadows are especially sensitive to such fluctuations. We conducted vegetation sampling in a sedge-grass dominated Lake Michigan drowned river mouth wetland in 1995, 2002, and 2010 following high lake levels in 1986 and 1997. We also conducted photointerpretation studies in 16 years dating back to 1965 to include responses to high lake levels in 1952 and 1974. Topographic data were collected to assess their influence on areal extent of sedge-grass meadow. Dominant species in short emergent and submersed/floating plant communities changed with water availability from 1995 to extreme low lake levels in 2002 and 2010. Sedge-grass meadow was dominated by Calamagrostis canadensis and Carex stricta in all years sampled, but Importance Values differed among years partly due to sampling in newly exposed areas. Photointerpretation studies showed a significant relation between percent of wetland in sedge-grass meadow and summer lake level, as well as the number of years since an extreme high lake level. From the topographic map created, we calculated the cumulative area above each 0.2-m contour to determine the percent of wetland dewatered in select years following extreme high lake levels. When compared with percent sedge-grass meadow in those years, relative changes in both predicted land surface and sedge-grass meadow demonstrated that accuracy of lake level as a predictor of area of sedge-grass meadow is dependent on topography. Our results regarding relations of plant-community response to hydrology are applicable to other Great Lakes wetlands.