The Bobolink (Dolichonyx oryzivorus) is a long-distance migratory grassland songbird whose global population is in long-term decline, largely due to habitat loss and intensification of agricultural ...practices. To better understand the factors affecting their annual cycle, we used a known-age population of male Bobolinks (n = 121) breeding in agricultural grasslands of Vermont and explored how variation in plumage (extent of yellow in cap) and body morphology (body mass and wing length) explained variation in apparent survival. Bobolink body mass and wing length varied between years 2-5. Bobolink cap size did not change with age. However, none of the 3 morphological characters explained variation in apparent survival. Our results highlight the challenges associated with understanding variation in individual quality relative to age, particularly regarding factors that affect demographic processes in declining species. Received 28 March 2022. Accepted 16 July 2022.
We report the first records of thick-billed longspur (Rhynchophanes mccownii) in Nuevo Leon and San Luis Potosi, Mexico, which constitute out-of-range southeastern observations. We observed ...thickbilled longspurs during February 2020 as part of two wintering mixed flocks, the first one with horned larks (Eremophila alpestris) in a Mexican prairie dog colony (Cynomys mexicanus) in Nuevo Leon, and the second one with chestnut-collared longspurs (Calcarius ornatus) in a dirt dam near the dry lake bed of Laguna La Mesita, San Luis Potosi, Mexico. Both sites were grasslands with high bare ground values (>80%).
AIM: National and international policy frameworks, such as the European Union's Renewable Energy Directive, increasingly seek to conserve and reference ‘highly biodiverse grasslands’. However, to ...date there is no systematic global characterization and distribution map for grassland types. To address this gap, we first propose a systematic definition of grassland. We then integrate International Vegetation Classification (IVC) grassland types with the map of Terrestrial Ecoregions of the World (TEOW). LOCATION: Global. METHODS: We developed a broad definition of grassland as a distinct biotic and ecological unit, noting its similarity to savanna and distinguishing it from woodland and wetland. A grassland is defined as a non‐wetland type with at least 10% vegetation cover, dominated or co‐dominated by graminoid and forb growth forms, and where the trees form a single‐layer canopy with either less than 10% cover and 5 m height (temperate) or less than 40% cover and 8 m height (tropical). We used the IVC division level to classify grasslands into major regional types. We developed an ecologically meaningful spatial catalogue of IVC grassland types by listing IVC grassland formations and divisions where grassland currently occupies, or historically occupied, at least 10% of an ecoregion in the TEOW framework. RESULTS: We created a global biogeographical characterization of the Earth's grassland types, describing approximately 75% of IVC grassland divisions with ecoregions. We mapped 49 IVC grassland divisions. Sixteen additional IVC grassland divisions are absent from the map because of the fine‐scale distribution of these grassland types. MAIN CONCLUSIONS: The framework provided by our geographical mapping effort provides a systematic overview of grasslands and sets the stage for more detailed classification and mapping at finer scales. Each regional grassland type can be characterized in terms of its range of biodiversity, thereby assisting in future policy initiatives.
Wakehurst's North American Prairie Annette, Francis
Curtis's botanical magazine (1995),
December 2023, 2023-12-00, 20231201, Volume:
40, Issue:
4
Journal Article
Peer reviewed
Open access
Summary
The theory behind the ecology and plant associations of prairie grasslands is summarised, and compared with conventional horticultural perennial planting.
Stellera chamaejasme L. is a widely distributed poisonous plant in Chinese degraded grasslands. To investigate the role of endophytic fungi (EF) in S. chamaejasme's quick spread in grasslands, the ...endophytic fungal community of S. chamaejasme was studied through culture-dependent and culture-independent methods, and the plant-growth-promoting (PGP) traits of some culturable isolates were tested. Further, the growth-promoting effects of 8 isolates which showed better PGP traits were evaluated by pot experiments. The results showed that a total of 546 culturable EF were isolated from 1114 plant tissue segments, and the colonization rate (CR) of EF in roots (33.27%) was significantly higher than that in shoots (22.39%). Consistent with this, the number of specific types of EF was greater in roots (8 genera) than in shoots (1 genus). The same phenomenon was found in culture-independent study. There were 95 specific genera found in roots, while only 18 specific genera were found in shoots. In addition, the dominant EF were different between the two study methods. Cladosporium (18.13%) and Penicillium (15.93%) were the dominant EF in culture-dependent study, while Apiotrichum (13.21%) and Athelopsis (5.62%) were the dominant EF in culture-independent study. PGP trait tests indicated that 91.30% of the tested isolates (69) showed phosphorus solubilization, IAA production, or siderophores production activity. The benefit of 8 isolates on host plants' growth was further studied by pot experiments, and the results indicated that all of the isolates can improve host plants' growth. Among them, STL3G74 (Aspergillus niger) showed the best growth-promotion effect; it can increase the plant's shoot and root dry biomass by 68.44% and 74.50%, respectively, when compared with the controls. Our findings revealed that S. chamaejasme has a wide range of fungal endophytic assemblages, and most of them possess PGP activities, which may play a key role in its quick spread in degraded grasslands.
The uptake of natural radioactivity by pasture-grass collected from seven different grasslands of Digor was calculated. The activities of .sup.226Ra, .sup.232Th and .sup.40K in pasture-grass were in ...the range of 21.8 ± 6.3-49.6 ± 13.4, 51.9 ± 13.2-127.7 ± 23.8 and 309.5 ± 33.5-807.3 ± 64.4 Bq kg.sup.-1, respectively. The soil to pasture-grass transfer factors were evaluated and determined to be in the range from 0.26 ± 0.13 to 0.69 ± 0.34, 0.64 ± 0.27 to 1.99 ± 0.40 and 0.64 ± 0.014 to 1.40 ± 0.032 for .sup.226Ra, .sup.232Th and .sup.40K, respectively. The distribution of .sup.226Ra and .sup.232Th in different parts of pasture-grass indicated a decreasing tendency in order of root > stem > leaf. .sup.40K mainly accumulated in stem of pasture-grass and is followed by declining trend stem > leaf > root.
We expand the concept of "old growth" to encompass the distinct ecologies and conservation values of the world's ancient grass-dominated biomes. Biologically rich grasslands, savannas, and ...open-canopy woodlands suffer from an image problem among scientists, policy makers, land managers, and the general public, that fosters alarming rates of ecosystem destruction and degradation. These biomes have for too long been misrepresented as the result of deforestation followed by arrested succession. We now know that grassy biomes originated millions of years ago, long before humans began deforesting. We present a consensus view from diverse geographic regions on the ecological characteristics needed to identify old-growth grasslands and to distinguish them from recently formed anthropogenic vegetation. If widely adopted, the old-growth grassland concept has the potential to improve scientific understanding, conservation policies, and ecosystem management.
Intensively managed grass production in high-rainfall temperate climate zones is a globally important source of N.sub.2 O. Many of these grasslands are occasionally tilled to rejuvenate the sward, ...and this can lead to increased N.sub.2 O emissions. This was investigated by comparing N.sub.2 O fluxes from two adjacent intensively managed grazed grasslands in Scotland, one of which was tilled. A combination of eddy covariance, high-resolution dynamic chamber and static chamber methods was used. N.sub.2 O emissions from the tilled field increased significantly for several days immediately after ploughing and remained elevated for approximately 2 months after the tillage event contributing to an estimated increase in N.sub.2 O fluxes of 0.85â¯Â±â¯0.11â¯kgâ¯N.sub.2 O-Nâ¯ha.sup.-1 . However, any influence on N.sub.2 O emissions after this period appears to be minimal. The cumulative N.sub.2 O emissions associated with the tillage event and a fertiliser application of 70â¯kg N ammonia nitrate from one field were not significantly different from the adjacent untilled field, in which two fertiliser applications of 70â¯kg N ammonia nitrate occurred during the same period. Total cumulative fluxes calculated for the tilled and untilled fields over the entire 175-day measurement period were 2.14â¯Â±â¯0.18 and 1.65â¯Â±â¯1.02â¯kgâ¯N.sub.2 O-Nâ¯ha.sup.-1, respectively.
Intensively managed grass production in high rainfall temperate climate zones is a globally important source of N.sub.2 O. Many of these grasslands are occasionally tilled and can lead to increased ...N.sub.2 O emissions. This was investigated by comparing N.sub.2 O fluxes from two adjacent intensively managed grazed grasslands in Scotland, one of which was tilled. A combination of eddy covariance, high resolution dynamic chamber and static chamber methods greatly improved the temporal and spatial coverage of N.sub.2 O fluxes before and after the tillage event and is recommended to be followed in future studies. Total cumulative fluxes calculated for the tilled and un-tilled fields over the 175 day measurement period were 2.45 ± 0.27 and 2.08 ± 0.23 kg N.sub.2 O-N ha.sup.−1, respectively. N.sub.2 O emissions from the tilled field increased significantly for several days immediately after ploughing and remained elevated for approximately two months after the tillage event contributing to an estimated increase in N.sub.2 O fluxes of 1.08 ± 0.14 kg N.sub.2 O-N ha.sup.−1 . Cumulative fluxes calculated over a 28 day period in August after the application of 70 kg-N ha.sup.−1 as ammonium nitrate to both fields were estimated at 0.42 ± 0.15 and 0.75 ± 0.14 kg N.sub.2 O N ha.sup.−1 for the tilled and un-tilled fields, respectively. The tillage event appears to have substantially increased N.sub.2 O fluxes from the tilled grassland field over a two month period; however, this increase may have been fractionally offset by a decrease in emissions after the August fertilisation event.
