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Full-Text Articles in Physical Sciences and Mathematics
Grazing Effects On Soil Seed Banks: A Global Synthesis, Shi Yafei
Grazing Effects On Soil Seed Banks: A Global Synthesis, Shi Yafei
IGC Proceedings (1997-2023)
Livestock grazing is a major disturbance affecting plant diversity and abundance in terrestrial ecosystems. The intermediate disturbance hypothesis (IDH) predicts that moderate-intensity grazing should produce the highest species diversity, while the Milchunas-Sala-Lauenroth (MSL) model posits that the IDH is valid only for mesic areas. However, it remains unclear how grazing affects soil seed bank and whether or not the IDH or MSL models are valid for soil seed bank communities. Here, we presented a global meta-analysis synthesizing 483 observations: we found that grazing had a negative effect on soil seed bank abundance, but did not alter seed bank richness. Further …
Beyond The Boom: Integrated Approaches To Managing Weeds And Brush, M. L. Treadwell, D. Burson
Beyond The Boom: Integrated Approaches To Managing Weeds And Brush, M. L. Treadwell, D. Burson
IGC Proceedings (1997-2023)
William Bray stated in his 1904 report, The Timber of the Edwards Plateau of Texas, "This struggle of the timberlands to capture the grasslands is an old warfare....it spreads like infection.” This trend is true today and especially pronounced in the Great Plains, where only 1/4 of the Great Plains’ original grasslands remains intact. Species like honey mesquite, honey locust, black locust, sumac, dogwood, post oak, winged elm, Siberian elm, salt cedar, huisache, Eastern redcedar, Ashe and redberry juniper, pricklypear, sericea lespedeza, and many other species represent alarming rates of spread and rapid establishment throughout Great Plains grasslands. Although, these …
Grazing Effects On Soil Seed Banks: A Global Synthesis, Shi Yafei
Grazing Effects On Soil Seed Banks: A Global Synthesis, Shi Yafei
IGC Proceedings (1997-2023)
Livestock grazing is a major disturbance affecting plant diversity and abundance in terrestrial ecosystems. The intermediate disturbance hypothesis (IDH) predicts that moderate-intensity grazing should produce the highest species diversity, while the Milchunas-Sala-Lauenroth (MSL) model posits that the IDH is valid only for mesic areas. However, it remains unclear how grazing affects soil seed bank and whether or not the IDH or MSL models are valid for soil seed bank communities. Here, we presented a global meta-analysis synthesizing 483 observations: we found that grazing had a negative effect on soil seed bank abundance, but did not alter seed bank richness. Further …
Grass Diversity And Pasture Quality Baseline Assessement In Central Madagascar, O. P. Nanjarisoa, L. Randriamanalina, Wayne F. Truter, M. T. Rajaonah, C. E. R. Lehmann, C. Birkinshaw, L. Rakotonirina, D. Miarinjanahary, N. L. Raharinirina, M. S. Vorontsova
Grass Diversity And Pasture Quality Baseline Assessement In Central Madagascar, O. P. Nanjarisoa, L. Randriamanalina, Wayne F. Truter, M. T. Rajaonah, C. E. R. Lehmann, C. Birkinshaw, L. Rakotonirina, D. Miarinjanahary, N. L. Raharinirina, M. S. Vorontsova
IGC Proceedings (1997-2023)
Poaceae family contributes to Madagascar’s biodiversity hotspot with 217 of 541 grass species endemic to the island, although their forage value is unknown, at least in the scientific literature. Our research aims 1) to describe the diversity of native and endemic grasses thereby recognising the role of grass species diversity in forage and ecosystem management and 2) to provide new knowledge about pasture management based on the relationship between grazing capacity and productivity within experimental pastureland plots under different fire and grazing treatments. Our study seeks to provide information to inform improvements in livestock nutrition via grazing management of natural …
Tiller Demography Within Synthetic Grass Populations, K. J. Moore, C. Córdova
Tiller Demography Within Synthetic Grass Populations, K. J. Moore, C. Córdova
IGC Proceedings (1997-2023)
Like other populations of biological organisms, the collective aging structure of a population of grass tillers has meaning and consequences far beyond the development of an individual within it. Using various methods, it is possible to assign numerical indices to tiller development so that it can be described numerically. By sampling a population of tillers and assigning a numerical index to each, the average stage of tillers within a population can be calculated and a repeatable assessment of its development determined. The average or mean stage count (MSC) of tiller development is commonly calculated and used to compare the development …
Diversity And Adaptation Of Perennial Plants From North Africa: Legumes And Grasses, Aissa Abdelguerfi, M. Laouar, K. Abbas, M. M'Hammedi Bouzina
Diversity And Adaptation Of Perennial Plants From North Africa: Legumes And Grasses, Aissa Abdelguerfi, M. Laouar, K. Abbas, M. M'Hammedi Bouzina
IGC Proceedings (1997-2023)
A variety of climates, soil types and reliefs characterise North Africa (Algeria, Morocco, and Tunisia). These natural conditions have produced a large diversity of environments, landscapes, plant formations and flora. Several factors have contributed to the spread of a wide floristic variety: the influence of the Mediterranean in the north and in the north-east, the Atlantic in the west, and the Sahara in the south, as well as the presence of mountain ranges, particularly the Rif, the Tell Atlas, the Sahara Atlas, the Middle Atlas, the High Atlas, and the Anti-Atlas. This diversity of landscapes, environments and ecosystems has generated …
Plant Functional Types And Grazing Management In Mediterranean Grassland: An 11-Year Synthesis, Marcelo Sternberg, Zalmen Henkin, Avi Perevolotsky, M. Gutman, Eugene D. Ungar
Plant Functional Types And Grazing Management In Mediterranean Grassland: An 11-Year Synthesis, Marcelo Sternberg, Zalmen Henkin, Avi Perevolotsky, M. Gutman, Eugene D. Ungar
IGC Proceedings (1997-2023)
Mediterranean ecosystems have high seasonality in resource availability, high year-to-year rainfall variability, many annual plants in the forage and a long history of grazing and disturbance. These facts, and results of previous studies (Sternberg et al., 2000) suggested that stocking rates could be increased above those of traditional grazing. However, the long-term effects of intensive grazing on the vegetation were not fully known. This study aimed to evaluate the responses of plant functional types (PFT) and community structure to different regimes of cattle grazing in Mediterranean grassland, particularly at high stocking rates.
The Effect Of Grazing On Rare And Common Grasses And Forbs In The Mediterranean Coastal Desert Of Egypt, A. El-Keblawy, A. Ramadan
The Effect Of Grazing On Rare And Common Grasses And Forbs In The Mediterranean Coastal Desert Of Egypt, A. El-Keblawy, A. Ramadan
IGC Proceedings (1997-2023)
Large parts of the rangelands in the Arab countries are either overgrazed or gradually deteriorating due to large numbers of livestock and unrestricted grazing (Assaeed, 1997). Protection of vegetation against grazing in desert environments has been suggested as a feasible approach to halting land degradation and rehabilitating rangelands (El-Keblawy, 2003). However, little is known about the response of different plant life forms and life cycles to grazing. The objectives of this study were to address this point and to test the response of rare and common forbs and grasses to protection against grazing.
The Relationship Between Species Diversity And Productivity Of Cool-Season Grassland, S. E. Florine, Kenneth J. Moore, Steven L. Fales, R. L. Hintz
The Relationship Between Species Diversity And Productivity Of Cool-Season Grassland, S. E. Florine, Kenneth J. Moore, Steven L. Fales, R. L. Hintz
IGC Proceedings (1997-2023)
Iowa grasslands consist mainly of introduced cool-season grasses and forbs. Many of these species are well adapted and have become naturalised. Most of these grasslands are located on marginal sites with heterogeneous soils and topography. Consequently, there is significant variation in the botanical composition and biomass productivity within and across grassland sites. This experiment aimed to evaluate the botanical composition and biomass productivity of representative grasslands and to determine if there was a relationship between grassland species diversity and biomass production across sites.
Operating Systems Of The Meadows In Semi-Arid Region Of Algeria, K. Abbas, M. Abdelguerfi-Laouar, Aissa Abdelguerfi, T. Madani, A. Mebarkia
Operating Systems Of The Meadows In Semi-Arid Region Of Algeria, K. Abbas, M. Abdelguerfi-Laouar, Aissa Abdelguerfi, T. Madani, A. Mebarkia
IGC Proceedings (1997-2023)
Permanent meadows are the base of the fodder resources and also provide environmental services (MAP France, 2002). The function of fodder production is no longer solely to ensure bulk agricultural production. It must also allow the development of livestock products of good quality, contribute to environmental protection, the quality of the landscape and ensure a viable economic activity in the rural areas. These areas have decreased greatly (from 1 million ha at the beginning of the century (Lapeyronie, 1982) to less than 300,000 ha in 2000), in particular in the semi-arid zones at high altitude; however they contribute very effectively …
Pasture Condition Scoring, James B. Cropper
Pasture Condition Scoring, James B. Cropper
IGC Proceedings (1997-2023)
A pasture condition score sheet has been developed for use in the United States. It has rating criteria for key indicators that are used to ascertain if some areas of pasture management could be improved. It can also help evaluate what is causing less than desirable pasture conditions. Pasture condition scoring involves the visual and tactual evaluation of ten indicators that rate a pasture's overall condition. The ten indicators are: percent desirable plants, plant cover, plant diversity, plant residue, plant vigor, percent legume, uniformity of use, livestock concentration areas, soil compaction, and erosion (sheet and rill, gully, streambank and shoreline, …
Does Aflp Diversity Reflect Consanguinity Within Meadow Fescue Breeding Material?, B. Boller, R. Kölliker
Does Aflp Diversity Reflect Consanguinity Within Meadow Fescue Breeding Material?, B. Boller, R. Kölliker
IGC Proceedings (1997-2023)
Cultivars of perennial grass species are usually synthetics with a limited number of constituent parental clones, prone to inbreeding depression. Plant breeders aim at a balance between intensity of selection and maintenance of genetic diversity when making their choice of parent clones in an intuitive way, aided by fragmentary pedigree information. Molecular markers offer new opportunities for assessing genetic diversity among selected plants. The objective of the investigation presented here is to check if the genetic distance as measured by AFLP polymorphisms reflects consanguinity among Festuca pratensis individuals from our breeding programme.
Genetic Diversity And Heterosis In Perennial Ryegrass, U. K. Posselt
Genetic Diversity And Heterosis In Perennial Ryegrass, U. K. Posselt
IGC Proceedings (1997-2023)
Plant breeders are concerned with the diversity among and within breeding populations, because it largely determines the future prospects of success in breeding programs. DNA markers provide a powerful tool for the assessment of genetic diversity. The relationship between genetic diversity and heterosis has been investigated in several species (Melchinger, 1999). In hybrid breeding programs divergent genepools have been established in the past, according to heterotic patterns based on testcross information. In the last decade it has been shown, that new breeding materials can be assigned to already existing gene pools using molecular markers. The phenomenon of heterosis has been …
Genetic And Phenotypic Diversity Of Swiss Red Clover Landraces, D. Herrmann, B. Boller, F. Widmer, R. Kölliker
Genetic And Phenotypic Diversity Of Swiss Red Clover Landraces, D. Herrmann, B. Boller, F. Widmer, R. Kölliker
IGC Proceedings (1997-2023)
Mattenklee landraces are persistent and locally adapted Swiss red clover populations. About 100 populations are preserved and may represent a significant yet poorly characterised genetic resource for temperate regions. Genetic characterisation is important in order to improve cultivars, manage genetic resources and to maintain or restore biodiversity. The objectives of this study were to analyse genetic diversity, investigate potential ancestry and to elucidate the congruence of phenotypic and genetic structure of Mattenklee landraces.
Genetic Diversity In Colonial Bentgrass (Agrostis Capillaris L.) Revealed By Ecori/Msei And Psti/Msei Aflp Markers, H. Zhao, S. Bughrara
Genetic Diversity In Colonial Bentgrass (Agrostis Capillaris L.) Revealed By Ecori/Msei And Psti/Msei Aflp Markers, H. Zhao, S. Bughrara
IGC Proceedings (1997-2023)
Colonial bentgrass species (Agrostis capillaris L.) is a potential genetic resource for the improvement of other bentgrass species (Agrostis spp.) with regard to resistance to environmental stresses and diseases. Transferring resistance from colonial to other bentgrass species is a promising goal in turfgrass breeding programs (Belanger, 2003). Assessment of genetic diversity among accessions of colonial bentgrass species will contribute to eliminate undesirable duplications in the germplasm collection and increase the efficiency of research efforts. It will allow researcher to select diverse resistance genes from different sources to incorporate and pyramid these resistance genes into creeping or other bentgrass …
Species Richness, Species Identity And Ecosystem Function In Managed Temperate Grasslands, S. C. Goslee, M. A. Sanderson, K. Soder
Species Richness, Species Identity And Ecosystem Function In Managed Temperate Grasslands, S. C. Goslee, M. A. Sanderson, K. Soder
IGC Proceedings (1997-2023)
Manipulation of plant species diversity may provide a way to improve the ecosystem functioning of managed systems by increasing productivity and suppressing weedy species. As yet, the functional role of species richness is not well-enough understood to enable practical application. We investigated the effects of differing species richness on community stability and invasion resistance in a grazed temperate grassland.
Intake And Milk Production Of Lactating Dairy Cows Grazing Diverse Forage Mixtures Over Two Grazing Seasons, K. Soder, M. A. Sanderson, J. L. Stack, L. Muller
Intake And Milk Production Of Lactating Dairy Cows Grazing Diverse Forage Mixtures Over Two Grazing Seasons, K. Soder, M. A. Sanderson, J. L. Stack, L. Muller
IGC Proceedings (1997-2023)
Voluntary intake and stocking rate are key determinants of animal performance on pasture. Greater plant diversity in grassland plant communities has been linked to increased primary production, greater stability in response to disturbance, and reduced weed pressure. Thus, increasing plant diversity may be one approach to improving animal productivity. An experiment was conducted to determine the effects of forage diversity on intake and milk production of lactating dairy cows over two grazing seasons.