Hao Yang, Karl Auerswald, Xiaoying Gong, Hans Schnyder, Yongfei Bai
Background
C4 plants have increased substantially during the past several decades in the grasslands of the Mongolian Plateau due to regional warming. Here, we explore how the patterns of abundances of C4 annuals and C4 perennials change over space and time.
Methods
A total of 280 sites with C4 plants were surveyed in four types of grasslands in 9 years. The relative biomasses of C4 plants (PC4), C4 annuals (PA4), and C4 perennials (PP4) were calculated. Structural equation modeling was used to analyze the drivers of changes in PA4 and PP4.
Results
At the regional scale, PA4 on average was 11% (±19%, SD) and PP4 was 13% (±19%, SD). Spatially, C4 annuals dominated the C4 communities within an east–west belt region along 44° N and tended to spread toward northern latitudes (about 0.5°) and higher altitudes in the east mountainous areas. The abundance of C4 annuals decreased, while that of C4 perennials increased. The patterns of C4 annuals and C4 perennials were mainly controlled by temperature, growing season precipitation, and dynamics between the two life forms.
Conclusions
C4 annuals exhibited competitive advantages in normal and wet years, while C4 perennials had competitive advantages in dry years. Grazing as a main human disturbance increased C4 annuals, but had no significant effect on C4 perennials.
{"title":"Climate and anthropogenic drivers of changes in abundance of C4 annuals and perennials in grasslands on the Mongolian Plateau","authors":"Hao Yang, Karl Auerswald, Xiaoying Gong, Hans Schnyder, Yongfei Bai","doi":"10.1002/glr2.12019","DOIUrl":"10.1002/glr2.12019","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>C4 plants have increased substantially during the past several decades in the grasslands of the Mongolian Plateau due to regional warming. Here, we explore how the patterns of abundances of C4 annuals and C4 perennials change over space and time.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A total of 280 sites with C4 plants were surveyed in four types of grasslands in 9 years. The relative biomasses of C4 plants (P<sub>C4</sub>), C4 annuals (P<sub>A4</sub>), and C4 perennials (P<sub>P4</sub>) were calculated. Structural equation modeling was used to analyze the drivers of changes in P<sub>A4</sub> and P<sub>P4</sub>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>At the regional scale, P<sub>A4</sub> on average was 11% (±19%, SD) and P<sub>P4</sub> was 13% (±19%, SD). Spatially, C4 annuals dominated the C4 communities within an east–west belt region along 44° N and tended to spread toward northern latitudes (about 0.5°) and higher altitudes in the east mountainous areas. The abundance of C4 annuals decreased, while that of C4 perennials increased. The patterns of C4 annuals and C4 perennials were mainly controlled by temperature, growing season precipitation, and dynamics between the two life forms.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>C4 annuals exhibited competitive advantages in normal and wet years, while C4 perennials had competitive advantages in dry years. Grazing as a main human disturbance increased C4 annuals, but had no significant effect on C4 perennials.</p>\u0000 </section>\u0000 </div>","PeriodicalId":100593,"journal":{"name":"Grassland Research","volume":"1 2","pages":"131-141"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/glr2.12019","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78527319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nictor Namoi, David Archer, Todd S. Rosenstock, Chunhwa Jang, Cheng-Hsien Lin, Arvid Boe, DoKyoung Lee
Background
Decisions regarding the conversion of land from an existing crop to bioenergy crops are critical for the sustainable production of both food and fuels. This study seeks to establish criteria for delineating land as “economically marginal”, and thus suited for growing switchgrass.
Methods
In this case study of an Illinois agricultural field, the profitability of switchgrass, with farmgate prices of $44 Mg−1, $66 Mg−1, or $88 Mg−1, was compared to corn and soybean crop prices. Further, the study also evaluates the profitability of switchgrass when replacing corn-based yield estimates from the Soil Productivity Index (SPI) of Illinois.
Results
Based on a dry-matter yield of 10.45 Mg ha−1, switchgrass can compete with soybeans only at the high price of $88 Mg−1, but depending on location, can compete with corn at $66 Mg−1. Across Illinois, at $88 ha−1, all Illinois land with SPI < 100% and 95% of land under SPI class C (SPI 100–116) is profitable under switchgrass. Switchgrass may not be profitable relative to corn grown in the SPI class A (SPI > 133) and only 7% of class B (SPI 117–132).
Conclusions
Our results show that land with drainage and erosion limitations is economically marginal when corn and soybean yields are low, and the farmgate price for switchgrass is greater than $66 Mg−1. However, this may not be possible on land where switchgrass is replacing frequent soybean rotations (corn–soybean ratio ≤ 1). Land used to produce only soybeans may only be marginal at the farmgate price of $88 Mg−1. Further studies need to be conducted to identify how much land can be converted to switchgrass without harming corn production.
{"title":"How profitable is switchgrass in Illinois, USA? An economic definition of marginal land","authors":"Nictor Namoi, David Archer, Todd S. Rosenstock, Chunhwa Jang, Cheng-Hsien Lin, Arvid Boe, DoKyoung Lee","doi":"10.1002/glr2.12017","DOIUrl":"10.1002/glr2.12017","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Decisions regarding the conversion of land from an existing crop to bioenergy crops are critical for the sustainable production of both food and fuels. This study seeks to establish criteria for delineating land as “economically marginal”, and thus suited for growing switchgrass.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In this case study of an Illinois agricultural field, the profitability of switchgrass, with farmgate prices of $44 Mg<sup>−1</sup>, $66 Mg<sup>−1</sup>, or $88 Mg<sup>−1</sup>, was compared to corn and soybean crop prices. Further, the study also evaluates the profitability of switchgrass when replacing corn-based yield estimates from the Soil Productivity Index (SPI) of Illinois.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Based on a dry-matter yield of 10.45 Mg ha<sup>−1</sup>, switchgrass can compete with soybeans only at the high price of $88 Mg<sup>−1</sup>, but depending on location, can compete with corn at $66 Mg<sup>−1</sup>. Across Illinois, at $88 ha<sup>−1</sup>, all Illinois land with SPI < 100% and 95% of land under SPI class C (SPI 100–116) is profitable under switchgrass. Switchgrass may not be profitable relative to corn grown in the SPI class A (SPI > 133) and only 7% of class B (SPI 117–132).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our results show that land with drainage and erosion limitations is economically marginal when corn and soybean yields are low, and the farmgate price for switchgrass is greater than $66 Mg<sup>−1</sup>. However, this may not be possible on land where switchgrass is replacing frequent soybean rotations (corn–soybean ratio ≤ 1). Land used to produce only soybeans may only be marginal at the farmgate price of $88 Mg<sup>−1</sup>. Further studies need to be conducted to identify how much land can be converted to switchgrass without harming corn production.</p>\u0000 </section>\u0000 </div>","PeriodicalId":100593,"journal":{"name":"Grassland Research","volume":"1 2","pages":"111-122"},"PeriodicalIF":0.0,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/glr2.12017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75633936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eric B. Duell, Karen R. Hickman, Gail W. T. Wilson
Background
Grasslands are globally imperiled, facing continued threats from anthropogenic disturbances. Seeding remains a common grassland restoration method, and yet, is typically met with limited success, partially because soils of degraded systems inhibit the germination of native species.
Methods
We assessed the germination success of 16 native grassland species sown in soils collected from a degraded grassland converted into a nonnative warm-season perennial grass, Bothriochloa ischaemum, and areas previously subjected to the eradication of this nonnative species. Our objectives were as follows: (1) determine native seed germination in soils collected from B. ischaemum or eradication control sites, compared to germination in native grassland soil, and (2) assess if native soil inoculation improves germination, compared to germination in degraded soils without inoculation.
Results
Germination of native species was exceedingly low when seeded into soil dominated by B. ischaemum, or in soil previously treated with combinations of herbicide and prescribed fire, relative to native grassland control. However, amendments with native grassland soil resulted in germination equivalent to native grasslands, alleviating the negative influences of degraded soils.
Conclusions
Our results highlight the role of native soil in improving the germination of desirable plant species following intensive management and soil degradation. Our research may improve restoration outcomes for managers focused on the conservation and restoration of grasslands.
{"title":"Inoculation with native grassland soils improves native plant species germination in highly disturbed soil","authors":"Eric B. Duell, Karen R. Hickman, Gail W. T. Wilson","doi":"10.1002/glr2.12018","DOIUrl":"10.1002/glr2.12018","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Grasslands are globally imperiled, facing continued threats from anthropogenic disturbances. Seeding remains a common grassland restoration method, and yet, is typically met with limited success, partially because soils of degraded systems inhibit the germination of native species.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We assessed the germination success of 16 native grassland species sown in soils collected from a degraded grassland converted into a nonnative warm-season perennial grass, <i>Bothriochloa ischaemum</i>, and areas previously subjected to the eradication of this nonnative species. Our objectives were as follows: (1) determine native seed germination in soils collected from <i>B. ischaemum</i> or eradication control sites, compared to germination in native grassland soil, and (2) assess if native soil inoculation improves germination, compared to germination in degraded soils without inoculation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Germination of native species was exceedingly low when seeded into soil dominated by <i>B. ischaemum</i>, or in soil previously treated with combinations of herbicide and prescribed fire, relative to native grassland control. However, amendments with native grassland soil resulted in germination equivalent to native grasslands, alleviating the negative influences of degraded soils.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our results highlight the role of native soil in improving the germination of desirable plant species following intensive management and soil degradation. Our research may improve restoration outcomes for managers focused on the conservation and restoration of grasslands.</p>\u0000 </section>\u0000 </div>","PeriodicalId":100593,"journal":{"name":"Grassland Research","volume":"1 2","pages":"75-83"},"PeriodicalIF":0.0,"publicationDate":"2022-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/glr2.12018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88542909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Grassland ecosystems in cold regions are typical of short growing seasons and limited primary productivity, rendering soil microorganisms as major ecosystem engineers in governing biogeochemical cycling. Climate warming and extensive livestock grazing have dramatically influenced soil microbial diversity and function in grassland worldwide, but it remains elusive how functional microbial communities exist and respond to global changes. Here, we present a review to highlight similarities and differences in soil functional microbial communities between alpine grasslands in the Qinghai-Tibet Plateau and temperate grasslands in the Inner Mongolian Plateau, both of which are major plateaus in China, but differ substantially in geography. We show that many specialized functional groups thrive under harsh conditions, exhibiting a high functional diversity. Their community compositions mirror the heterogeneity and complexity of grassland soils. Moreover, functional microbial responses to environmental changes have been extremely variable, with few consistent patterns across both plateaus. Because we identify a lack of technical standardization that prevents in-depth comparative studies for functional microbial communities, we conclude the review by outlining several research gaps that need to be filled in future studies.
{"title":"Functional profiles of soil microbial communities in the alpine and temperate grasslands of China","authors":"Yunfeng Yang, Jizhong Zhou, Xue Guo","doi":"10.1002/glr2.12011","DOIUrl":"10.1002/glr2.12011","url":null,"abstract":"<p>Grassland ecosystems in cold regions are typical of short growing seasons and limited primary productivity, rendering soil microorganisms as major ecosystem engineers in governing biogeochemical cycling. Climate warming and extensive livestock grazing have dramatically influenced soil microbial diversity and function in grassland worldwide, but it remains elusive how functional microbial communities exist and respond to global changes. Here, we present a review to highlight similarities and differences in soil functional microbial communities between alpine grasslands in the Qinghai-Tibet Plateau and temperate grasslands in the Inner Mongolian Plateau, both of which are major plateaus in China, but differ substantially in geography. We show that many specialized functional groups thrive under harsh conditions, exhibiting a high functional diversity. Their community compositions mirror the heterogeneity and complexity of grassland soils. Moreover, functional microbial responses to environmental changes have been extremely variable, with few consistent patterns across both plateaus. Because we identify a lack of technical standardization that prevents in-depth comparative studies for functional microbial communities, we conclude the review by outlining several research gaps that need to be filled in future studies.</p>","PeriodicalId":100593,"journal":{"name":"Grassland Research","volume":"1 1","pages":"3-13"},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/glr2.12011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79555750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neal W. Tilhou, Shawn M. Kaeppler, Michael D. Casler
Background
Switchgrass sward establishment results in up to 90% seedling mortality. The degree of selection during sward establishment has not been reported using modern genetic methods.
Methods
Pooled leaf samples were sequenced from replicated swards of 46 half-sib families from two breeding groups (lowland and hybrid) before and through 3 years of stand establishment. Pooled allele frequencies were then assessed using fixation indices (Fst) and an independent data set was used to predict the polygenic impact of establishment selection on two traits (heading date and winter survivorship). Last, the DNA pools were assigned survival rankings to predict the sward survival genomically estimated breeding values within the training data set.
Results
Strong and parallel selection occured in both breeding groups. Five genomic regions exceeded the significant threshold of 99.9% in >10 families, indicating consistent selection across families and breeding groups. Polygenic trait predictions determined that establishment selection was partially associated with winter survivorship but resulted in variable heading date alterations. The genomewide variation is consistent with selection for a small number of related parental lines.
Conclusions
This study observed strong selection for a small number of hybrid and coastal ecotype individuals which are promising germplasm sources for improved sward survival. This confirms prior reports of sward selection during grassland establishment and highlights the strength of pooled DNA sequencing for survival traits.
{"title":"Strong parallel evidence of selection during switchgrass sward establishment in hybrid and lowland ecotypes","authors":"Neal W. Tilhou, Shawn M. Kaeppler, Michael D. Casler","doi":"10.1002/glr2.12007","DOIUrl":"10.1002/glr2.12007","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Switchgrass sward establishment results in up to 90% seedling mortality. The degree of selection during sward establishment has not been reported using modern genetic methods.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Pooled leaf samples were sequenced from replicated swards of 46 half-sib families from two breeding groups (lowland and hybrid) before and through 3 years of stand establishment. Pooled allele frequencies were then assessed using fixation indices (<i>F</i><sub>st</sub>) and an independent data set was used to predict the polygenic impact of establishment selection on two traits (heading date and winter survivorship). Last, the DNA pools were assigned survival rankings to predict the sward survival genomically estimated breeding values within the training data set.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Strong and parallel selection occured in both breeding groups. Five genomic regions exceeded the significant threshold of 99.9% in >10 families, indicating consistent selection across families and breeding groups. Polygenic trait predictions determined that establishment selection was partially associated with winter survivorship but resulted in variable heading date alterations. The genomewide variation is consistent with selection for a small number of related parental lines.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This study observed strong selection for a small number of hybrid and coastal ecotype individuals which are promising germplasm sources for improved sward survival. This confirms prior reports of sward selection during grassland establishment and highlights the strength of pooled DNA sequencing for survival traits.</p>\u0000 </section>\u0000 </div>","PeriodicalId":100593,"journal":{"name":"Grassland Research","volume":"1 1","pages":"31-42"},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/glr2.12007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72917955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Allen A. Chen, Shui-zhang Fei, Andrew W. Lenssen, Kenneth J. Moore
Background
Summer vegetative dormancy is a desirable trait in cool-season grasses when they are interplanted with annual crops. Sandberg bluegrass (Poa secunda J. Presl.) shows summer dormancy, but the environmental cues that control dormancy remain unknown.
Methods
A controlled environment study using temperature and day length combinations of 32.2°C/15 h, 26.6°C/14 h, 21.1°C/13 h, and 15.5°C/12 h was conducted with P. secunda accessions PI232347, PI639272, and PI232348, and ‘Audubon’ red fescue as a nondormant control to determine the optimum treatment for dormancy induction. A second study using treatments of 26.6°C/14 h, 21.1°C/13 h, and 15.5°C/12 h was conducted to determine the thresholds for dormancy release. A third study used a factorial experiment with two temperatures (32.2°C and 15.5°C) and two day lengths (15 and 12 h) to differentiate between temperature and day length effects on dormancy induction.
Results
Of the four temperature and day length combinations, all except for 15.5°C/12 h resulted in dormancy by the end of 6 weeks, with 32.2°C/15 h inducing dormancy in only 17 days. Of the three treatments for dormancy release, 15.5°C/12 h broke dormancy the fastest in all accessions and released the most number of plants from dormancy. Considerable variation existed between accessions for the speed of dormancy release in the 21.1°C/13 h and 26.6°C/14 h treatments. The third study showed that temperature is the primary inducer for summer dormancy, while longer day length may promote dormancy under inductive temperatures.
Conclusions
This study identified the optimum photothermal for induction and release of summer dormancy in P. secunda, which will help future studies in elucidating the mechanism of summer dormancy.
夏季营养休眠是冷季草与一年生作物套种时的理想特性。桑德伯格蓝草(Poa secunda J. Presl.)表现出夏季休眠，但控制休眠的环境线索尚不清楚。方法采用32.2°C/15 h、26.6°C/14 h、21.1°C/13 h和15.5°C/12 h的温度和日照组合，以“奥杜邦”红羊茅为非休眠对照，确定诱导休眠的最佳处理。第二项研究采用26.6°C/14 h、21.1°C/13 h和15.5°C/12 h处理，以确定休眠释放的阈值。第三项研究采用两种温度(32.2°C和15.5°C)和两种白天长度(15和12小时)的析因实验来区分温度和白天长度对诱导休眠的影响。结果4种温度和日长组合中，除15.5°C/12 h外，其余均在6周后休眠，其中32.2°C/15 h仅在17 d内休眠。在3个解除休眠处理中，15.5°C/12 h解除休眠最快，解除休眠植株数量最多。在21.1°C/13 h和26.6°C/14 h处理下，不同种质间的休眠释放速度存在较大差异。第三项研究表明，温度是夏季休眠的主要诱因，而在诱导温度下，较长的日照可能促进休眠。结论本研究确定了诱导和释放白杨夏季休眠的最佳光热条件，为进一步研究白杨夏季休眠机制奠定了基础。
{"title":"Photothermal controls of vegetative dormancy in Poa secunda","authors":"Allen A. Chen, Shui-zhang Fei, Andrew W. Lenssen, Kenneth J. Moore","doi":"10.1002/glr2.12008","DOIUrl":"10.1002/glr2.12008","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Summer vegetative dormancy is a desirable trait in cool-season grasses when they are interplanted with annual crops. Sandberg bluegrass (<i>Poa secunda</i> J. Presl.) shows summer dormancy, but the environmental cues that control dormancy remain unknown.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A controlled environment study using temperature and day length combinations of 32.2°C/15 h, 26.6°C/14 h, 21.1°C/13 h, and 15.5°C/12 h was conducted with <i>P. secunda</i> accessions PI232347, PI639272, and PI232348, and ‘Audubon’ red fescue as a nondormant control to determine the optimum treatment for dormancy induction. A second study using treatments of 26.6°C/14 h, 21.1°C/13 h, and 15.5°C/12 h was conducted to determine the thresholds for dormancy release. A third study used a factorial experiment with two temperatures (32.2°C and 15.5°C) and two day lengths (15 and 12 h) to differentiate between temperature and day length effects on dormancy induction.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Of the four temperature and day length combinations, all except for 15.5°C/12 h resulted in dormancy by the end of 6 weeks, with 32.2°C/15 h inducing dormancy in only 17 days. Of the three treatments for dormancy release, 15.5°C/12 h broke dormancy the fastest in all accessions and released the most number of plants from dormancy. Considerable variation existed between accessions for the speed of dormancy release in the 21.1°C/13 h and 26.6°C/14 h treatments. The third study showed that temperature is the primary inducer for summer dormancy, while longer day length may promote dormancy under inductive temperatures.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This study identified the optimum photothermal for induction and release of summer dormancy in <i>P. secunda</i>, which will help future studies in elucidating the mechanism of summer dormancy.</p>\u0000 </section>\u0000 </div>","PeriodicalId":100593,"journal":{"name":"Grassland Research","volume":"1 1","pages":"43-52"},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/glr2.12008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79552555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bernhard Schmid, Martin Schmitz, Michael Rzanny, Michael Scherer-Lorenzen, Peter N. Mwangi, Wolfgang W. Weisser, Andrew Hector, Roland Schmid, Dan F. B. Flynn
Background
Positive effects of plant species richness on community biomass in biodiversity experiments are often stronger than those from observational field studies. This may be because experiments are initiated with randomly assembled species compositions whereas field communities have experienced filtering.
Methods
We compared aboveground biomass production of randomly assembled communities of 2–16 species (controls) with experimentally filtered communities from which subordinate species were removed, resulting in removal communities of 1–8 species.
Results
Removal communities had (1) 12.6% higher biomass than control communities from which they were derived, that is, with double species richness and (2) 32.0% higher biomass than control communities of equal richness. These differences were maintained along the richness gradient. The increased productivity of removal communities was paralleled by increased species evenness and complementarity.
Conclusions
Result (1) indicates that subordinate species can reduce community biomass production, suggesting a possible explanation for why the most diverse field communities sometimes do not have the highest productivity. Result (2) suggests that if a community of S species has been derived by filtering from a pool of 2S randomly chosen species it is more productive than a community derived from a pool of S randomly chosen species without filtering.
{"title":"Removing subordinate species in a biodiversity experiment to mimic observational field studies","authors":"Bernhard Schmid, Martin Schmitz, Michael Rzanny, Michael Scherer-Lorenzen, Peter N. Mwangi, Wolfgang W. Weisser, Andrew Hector, Roland Schmid, Dan F. B. Flynn","doi":"10.1002/glr2.12009","DOIUrl":"10.1002/glr2.12009","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Positive effects of plant species richness on community biomass in biodiversity experiments are often stronger than those from observational field studies. This may be because experiments are initiated with randomly assembled species compositions whereas field communities have experienced filtering.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We compared aboveground biomass production of randomly assembled communities of 2–16 species (controls) with experimentally filtered communities from which subordinate species were removed, resulting in removal communities of 1–8 species.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Removal communities had (1) 12.6% higher biomass than control communities from which they were derived, that is, with double species richness and (2) 32.0% higher biomass than control communities of equal richness. These differences were maintained along the richness gradient. The increased productivity of removal communities was paralleled by increased species evenness and complementarity.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Result (1) indicates that subordinate species can reduce community biomass production, suggesting a possible explanation for why the most diverse field communities sometimes do not have the highest productivity. Result (2) suggests that if a community of S species has been derived by filtering from a pool of 2S randomly chosen species it is more productive than a community derived from a pool of S randomly chosen species without filtering.</p>\u0000 </section>\u0000 </div>","PeriodicalId":100593,"journal":{"name":"Grassland Research","volume":"1 1","pages":"53-62"},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/glr2.12009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88412549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Grasslands provide a wide variety of ecosystem services that contribute to human wellbeing. While an increasing number of studies are evaluating the monetary value of grassland ecosystem services, most of them focus on specific grassland ecosystem services at regional or local scales, and they use different assessment methods.
Methods
This paper provides a comprehensive assessment of the economic value of global grassland ecosystem services based on a meta-analysis of 702 observations from 134 primary studies.
Results
The economic values of different ecosystem services cover a wide range of grassland types, regions, and estimation methods. The annual economic value per hectare ranges from $3955 for semidesert grasslands to $5466 for tropical grasslands. On average, regulating services have the highest value, which is approximately four times that of provisioning services or approximately eight times that of food supply services. Several factors impact the estimated ecosystem service values, including the evaluation method, source and year of publication, and study site. The results indicate that the annual economic value of global grasslands exceeds $20.8 trillion.
Conclusions
The findings of this study not only provide useful information for understanding the economic value of various ecosystem services associated with different types of grasslands but also have important policy implications for the ecological conservation of grassland globally.
{"title":"The economic value of grassland ecosystem services: A global meta-analysis","authors":"Huifang Liu, Lingling Hou, Nannan Kang, Zhibiao Nan, Jikun Huang","doi":"10.1002/glr2.12012","DOIUrl":"10.1002/glr2.12012","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Grasslands provide a wide variety of ecosystem services that contribute to human wellbeing. While an increasing number of studies are evaluating the monetary value of grassland ecosystem services, most of them focus on specific grassland ecosystem services at regional or local scales, and they use different assessment methods.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This paper provides a comprehensive assessment of the economic value of global grassland ecosystem services based on a meta-analysis of 702 observations from 134 primary studies.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The economic values of different ecosystem services cover a wide range of grassland types, regions, and estimation methods. The annual economic value per hectare ranges from $3955 for semidesert grasslands to $5466 for tropical grasslands. On average, regulating services have the highest value, which is approximately four times that of provisioning services or approximately eight times that of food supply services. Several factors impact the estimated ecosystem service values, including the evaluation method, source and year of publication, and study site. The results indicate that the annual economic value of global grasslands exceeds $20.8 trillion.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The findings of this study not only provide useful information for understanding the economic value of various ecosystem services associated with different types of grasslands but also have important policy implications for the ecological conservation of grassland globally.</p>\u0000 </section>\u0000 </div>","PeriodicalId":100593,"journal":{"name":"Grassland Research","volume":"1 1","pages":"63-74"},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/glr2.12012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76573429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniel Forster, Samuli Helama, Matthew T. Harrison, Clarence Alan Rotz, Jinfeng Chang, Phillippe Ciais, Elizabeth Pattey, Perttu Virkajärvi, Narasinha Shurpali
Past assessments report negative impacts of the climate crisis in boreal areas; but milder and shorter winters and elevated atmospheric CO2 may provide opportunities for agricultural productivity potentially playing a significant role in future food security. Arable cropping systems are expanding in boreal areas, but the regional mainstay will likely continue to be livestock production. Agroecological models can when appropriately calibrated and evaluated, facilitate improved productivity while minimising environmental impacts by identifying system interactions, and quantifying greenhouse gas emissions, soil carbon stocks and fertiliser use. While models designed for temperate and tropical zones abound, few are developed specifically for boreal zones, and there is uncertainty around the performance of existing models in boreal areas. We reviewed model performance across boreal environments and management systems. We identified a dearth of modelling studies in boreal regions, with the publication of three or less papers per year since the year 2000, constituting a significant research gap. Models IFSM and BASGRA_N performed best in grassland production, DNDC best in predicting soil N2O and NH3 emissions. No model outperformed all others, strengthening the case for ensemble modelling. Existing agroecological models would be worthy of further evaluation, providing model improvements designed for boreal systems.
{"title":"Use, calibration and verification of agroecological models for boreal environments: A review","authors":"Daniel Forster, Samuli Helama, Matthew T. Harrison, Clarence Alan Rotz, Jinfeng Chang, Phillippe Ciais, Elizabeth Pattey, Perttu Virkajärvi, Narasinha Shurpali","doi":"10.1002/glr2.12010","DOIUrl":"10.1002/glr2.12010","url":null,"abstract":"<p>Past assessments report negative impacts of the climate crisis in boreal areas; but milder and shorter winters and elevated atmospheric CO<sub>2</sub> may provide opportunities for agricultural productivity potentially playing a significant role in future food security. Arable cropping systems are expanding in boreal areas, but the regional mainstay will likely continue to be livestock production. Agroecological models can when appropriately calibrated and evaluated, facilitate improved productivity while minimising environmental impacts by identifying system interactions, and quantifying greenhouse gas emissions, soil carbon stocks and fertiliser use. While models designed for temperate and tropical zones abound, few are developed specifically for boreal zones, and there is uncertainty around the performance of existing models in boreal areas. We reviewed model performance across boreal environments and management systems. We identified a dearth of modelling studies in boreal regions, with the publication of three or less papers per year since the year 2000, constituting a significant research gap. Models IFSM and BASGRA_N performed best in grassland production, DNDC best in predicting soil N<sub>2</sub>O and NH<sub>3</sub> emissions. No model outperformed all others, strengthening the case for ensemble modelling. Existing agroecological models would be worthy of further evaluation, providing model improvements designed for boreal systems.</p>","PeriodicalId":100593,"journal":{"name":"Grassland Research","volume":"1 1","pages":"14-30"},"PeriodicalIF":0.0,"publicationDate":"2022-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/glr2.12010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85797651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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