Evidence for community structuring associated with the actinorhizal shrub Ceanothus americanus in tallgrass prairies in Illinois, USA

2011 ◽  
Vol 38 (9) ◽  
pp. 711 ◽  
Author(s):  
John B. Taft ◽  
Jeffrey O. Dawson

The role of the actinorhizal shrub Ceanothus americanus L. in community organisation of native grasslands was examined in three Illinois tallgrass prairie remnants. We asked can C. americanus structure tallgrass prairie at the patch scale through nitrogen fixation leading to differences in species assemblages and diversity? Expectations were that warm season (C4) graminoid species would be more abundant and species diversity would be greater outside Ceanothus patches than in patches associated with C. americanus where, based on results from numerous nitrogen augmentation and deposition studies, we expected greater abundance of cool season (C3) graminoid species and lower species diversity. Plots with and without association to C. americanus were compared for differences in floristic similarity, diversity, and C3 versus C4 graminoid species abundance. C3 graminoid species, including the adventive Poa pratensis L., were significantly more abundant in prairie associated with C. americanus than were C4 species. C4 species, such as Andropogon gerardi Vitman and Schizachyrium scopariumii (Michx.) Nash., were more abundant than C3 graminoid species in prairie patches without association to C. americanus. Means for diversity among plots associated with C. americanus were significantly lower than for other plots, nearly so for evenness and species density, but not different for sum total cover or total species richness. There were no statistically-significant differences in measures of mean total soil nitrogen at points along linear transects radiating from the base of C. americanus shrubs nor between mean soil amino-sugar-nitrogen concentrations within and outside of C. americanus patches. Nonetheless, comparative evidence supports the hypothesis that C. americanus structures composition and diversity at the local patch scale in tallgrass prairie.

2010 ◽  
Vol 26 (2) ◽  
pp. 114-126 ◽  
Author(s):  
Karie Wiltshire ◽  
Kathleen Delate ◽  
Mary Wiedenhoeft ◽  
Jan Flora

AbstractThe multifunctional agronomic, ecological, economic and social uses of grass-based agricultural systems in peri-urban Marion County, Iowa, were the subject of investigation from 2003 to 2005. Following a sociocultural analysis that identified diverse motivations of cow–calf operators, an on-farm, agroecological experiment was established with a member of the study group. The objective of the experiment was to investigate the feasibility of establishing a multifunctional prairie pasture in response to the operator's interest in certified organic, warm-season plant species paddocks. At the field level, the implementation of native grasses and legumes into fallow pasture without the use of herbicides under flash grazing, mowing and unmanaged control treatments showed differences in species establishment and pasture composition. After three growing seasons, native species were evident in all treatments, with no significant differences between grazing and mowing in total native species establishment. There was a trend toward greater native legume establishment in the control over the managed treatments. Thus, total species abundance was greatest in control plots, suggesting this treatment for maximum prairie pasture establishment without herbicides. Concurrence was observed between motivations expressed by cow–calf operators in the sociocultural study (i.e. biodiversity preservation and sustainable management of natural resources) and outcomes from the prairie pasture experimental system. Support for grass-based systems from local institutions at the community level is necessary for the expansion of prairie pastures in Iowa and throughout the tallgrass prairie region.


1992 ◽  
Vol 70 (8) ◽  
pp. 1596-1602 ◽  
Author(s):  
S. P. Bentivenga ◽  
B. A. D. Hetrick

Previous research on North American tallgrass prairie grasses has shown that warm-season grasses rely heavily on vesicular–arbuscular mycorrhizal symbiosis, while cool-season grasses are less dependent on the symbiosis (i.e., receive less benefit). This led to the hypothesis that cool-season grasses are less dependent on the symbiosis, because the growth of these plants occurs when mycorrhizal fungi are inactive. Field studies were performed to assess the effect of phenology of cool- and warm-season grasses on mycorrhizal fungal activity and fungal species composition. Mycorrhizal fungal activity in field samples was assessed using the vital stain nitro blue tetrazolium in addition to traditional staining techniques. Mycorrhizal activity was greater in cool-season grasses than in warm-season grasses early (April and May) and late (December) in the growing season, while mycorrhizal activity in roots of the warm-season grasses was greater (compared with cool-season grasses) in midseason (July and August). Active mycorrhizal colonization was relatively high in both groups of grasses late in the growing season, suggesting that mycorrhizal fungi may proliferate internally or may be parasitic at this time. Total Glomales sporulation was generally greater in the rhizosphere of cool-season grasses in June and in the rhizosphere of the warm-season grasses in October. A growth chamber experiment was conducted to examine the effect of temperature on mycorrhizal dependence of cool- and warm-season grasses. For both groups of grasses, mycorrhizal dependence was greatest at the temperature that favored growth of the host. The results suggest that mycorrhizal fungi are active in roots when cool-season grasses are growing and that cool-season grasses may receive benefit from the symbiosis under relatively cool temperature regimes. Key words: cool-season grasses, tallgrass prairie, vesicular–arbuscular mycorrhizae, warm-season grasses.


2015 ◽  
Vol 45 (2) ◽  
pp. 111-132 ◽  
Author(s):  
Edson Gomes de MOURA JÚNIOR ◽  
Raíssa Maria Sampaio de PAIVA ◽  
Angélica Cândida FERREIRA ◽  
Lucília Dias PACOPAHYBA ◽  
Aldaléa Sprada TAVARES ◽  
...  

Field collection and herbaria data did not allow to quantify the diversity of aquatic plants from Northern Brazil, so we could not detect biogeographic patterns. Therefore, our objectives were to identify and quantify the aquatic macrophytes of North Brazilian states, analyzing herbaria data plataforms (SpeciesLink and Flora do Brasil). The checklist was produced by bibliographic search (articles published between 1980 and 2000), herbaria collections of the platforms SpeciesLink and Flora do Brasil and field expeditions, where we utilized asystematic sampling. We also analyzed the floristic similarity of aquatic macrophytes among Northern Brazil, wetlands of distinct Brazilian regions and the Neotropics. We recorded 539 species, of which 48 are endemic to Brazil. The states with highest number of species were Amazonas and Pará, independently on platform. The most represented families were Poaceae (89 species), Podostemaceae (55), Cyperaceae (50) and Fabaceae (47). We highlight the unprecedent richness of Podostemaceae, due to our own field collection efforts on favorable habitats, 25 species being endemic. Emergent and/or amphibious plants (515) were dominant in total species richness and were best represented in lotic habitats. We found significant differences in richness and floristics among states, obtained from the platforms. There is floristic similarity among Northern states and other Brazilian wetlands. In conclusion, we observed a rich aquatic flora in Northern Brazil, in spite of scarcity of records for Acre, Rondonia and Tocantins; we highlight the unprecedent number of endemic species of Podostemaceae (25) and contrasting richness between SpeciesLink and Flora do Brasil.


2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Hellen K. Mandela ◽  
Mugatsia H. Tsingalia ◽  
Mary Gikungu ◽  
Wilbur M. Lwande

Pollination is an important ecosystem service in the maintenance of biodiversity and most importantly in food production. Pollination is on the decline due to habitat loss, exotic species invasions, pollution, overharvesting, and land use changes. This study analyzed the abundance and diversity of flower visitors’ of Ocimum kilimandscharicum in Kakamega forest with increasing distance from the forest edge. Data were collected through direct observation and sweep netting. Six study sites were identified along two transects each 2.5 km long and labeled A to F. Distance in metres from the forest edge to each site was A=221, B=72, C=83, D=198, E=113, and F=50. Sampling was done from 7:30 am to 4:00 pm, three days in a week for five months consecutively. Diversity indices of different flower visitors were calculated using the Shannon-Wiener diversity index. One-way analysis of variance was used to compare differences between sites and a two-sample t-test was used to identify mean significant differences in species diversity between the closest and the furthest sites. A total of 645 individuals belonging to 35 species were captured from 4 families. The highest diversity was at site F (H’= 2.38) which was closest to the forest edge and the lowest diversity was from site A (H’=1.44) which was furthest from the forest edge. Distance from the forest edge significantly influenced species diversity (F(3, 20)=14.67, p=0.024). Distance from the forest edge also significantly influenced species abundance between the furthest sites A, D, and E and the nearest sites F, B, and C to the forest edge (t=4.177; p=0.0312) and species richness (t=3.2893; p=0.0187). This study clearly demonstrates that Ocimum kilimandscharicum flower visitors play essential roles in pollination and their higher number of visits translates into higher numbers of seeds set. Many of these pollinators are associated with the forest and hence the need to conserve the Kakamega forest as a source pool for pollinators.


2007 ◽  
Vol 50 (6) ◽  
pp. 1033-1042 ◽  
Author(s):  
Yzel Rondon Súarez ◽  
Sabrina Bigatão Valério ◽  
Karina Keyla Tondado ◽  
Alexandro Cezar Florentino ◽  
Thiago Rota Alves Felipe ◽  
...  

The influence of spatial, temporal and environmental factors on fish species diversity in headwater streams in Paraguay and Paraná basins, Brazil was examined. A total of 4,605 individuals were sampled, distributed in 60 species. The sampled streams in Paraná basin presented a larger total species richness (42) than Paraguay streams (40). However the estimated richness was larger in Paraguay basin (53) than Paraná streams (50). The streams of Paraná basin had a greater mean species richness and evenness, while more individuals per sample were found in the Paraguay basin. Difference between the sub-basins were found in the Paraguay basin, while for the basin of Paraná, richness and evenness vary significantly between the sub-basins, but the number of individuals varied seasonally. The most important environmental factors to species diversity and abundance were altitude, water temperature, stream width and stream depth for both the basins.


2011 ◽  
Vol 57 (1) ◽  
Author(s):  
Karen Hickman ◽  
David Hartnett ◽  
Robert Cochran ◽  
Clenton Owensby

1987 ◽  
Vol 65 (11) ◽  
pp. 2410-2419 ◽  
Author(s):  
D. Faber-Langendoen ◽  
P. F. Maycock

Extensive prairie communities on Walpole Island Indian Reserve in Lake St. Clair, southwestern Ontario, were sampled for vegetation and soil profile characteristics. Two hundred and fifty-two species were found in the 20 stands. Dominant grasses included Calamagrostis canadensis, Andropogon gerardii, Sorghastrum nutans, Panicum virgatum, Poa pratensis, and Spartina pectinata. Dominant forbs were Pycnanthemum virginianum, Liatris spicata, Fragaria virginiana, Lysimachia quadriflora, and Viola papilionacea. Stands were ordered along a recognized moisture–substrate gradient divided into four segments; dry-mesic sandy, mesic sandy loam, wet-mesic sandy loam, and wet loam. Many species showed preferences for certain regions of the gradient. Species richness ranged between 44 and 91 species per stand. The composition of the vegetation was summarized for the four segments, using prevalent species lists. Effectiveness of the direct gradient analysis was assessed by ordination using reciprocal averaging and polar ordination. Percent sand, percent organic matter, and depth of A horizon were significant correlates of the primary axis. Frequent burning of the prairie by the Indians has effectively maintained these prairies. The composition of the Walpole Island prairies is similar to those in Michigan, Illinois, and Wisconsin, forming part of the eastern tallgrass prairie.


2020 ◽  
Vol 6 (29) ◽  
pp. eaaz9037
Author(s):  
Paula Villa Martín ◽  
Aleš Buček ◽  
Thomas Bourguignon ◽  
Simone Pigolotti

Oceans host communities of plankton composed of relatively few abundant species and many rare species. The number of rare protist species in these communities, as estimated in metagenomic studies, decays as a steep power law of their abundance. The ecological factors at the origin of this pattern remain elusive. We propose that chaotic advection by oceanic currents affects biodiversity patterns of rare species. To test this hypothesis, we introduce a spatially explicit coalescence model that reconstructs the species diversity of a sample of water. Our model predicts, in the presence of chaotic advection, a steeper power law decay of the species abundance distribution and a steeper increase of the number of observed species with sample size. A comparison of metagenomic studies of planktonic protist communities in oceans and in lakes quantitatively confirms our prediction. Our results support that oceanic currents positively affect the diversity of rare aquatic microbes.


2020 ◽  
Vol 55 (3) ◽  
pp. 329-343
Author(s):  
Kenneth W. McCravy ◽  
Jason E. Willand

Abstract The Carabidae is a diverse family of beetles with many species of interest in conservation and biological control. Carabid beetle adult seasonal activity patterns were studied in a west-central Illinois forest/reconstructed tallgrass prairie matrix over a 2-yr period using pitfall traps. We found a threefold or greater difference in carabid abundance between years. Despite lower abundance, a second year of sampling yielded seven previously undetected species. Abundance and species richness were greatest in May–July and lower in August–October. Relative abundance and species richness were consistent among months between years. Shannon diversity and effective number of species were lowest in June and July. Cyclotrachelus sodalis (LeConte) and Chlaenius platyderus Chaudoir were the two most abundant species, comprising 54.3% of total captures. These species were most abundant in July and June, respectively. Most species showed greatest abundance in spring or early summer, and declined thereafter. Collections of several species were suggestive of bimodal seasonal patterns. Carabid species composition differed significantly among months, but not between years. Our results document seasonal variation in carabid abundance and species composition, and show that sampling throughout the growing season, and multiple sampling years, provide substantial benefits for assessments of carabid diversity in this region.


Sign in / Sign up

Export Citation Format

Share Document