Movements of selected minnows between the lower Yellowstone River and its tributaries

2021 ◽  
pp. 45-56
Author(s):  
Michael B. Duncan ◽  
Robert G. Bramblett ◽  
Alexander V. Zale
Keyword(s):  
Empirical Evidence ◽  
Great Plains ◽  
Life Cycles ◽  
Population Connectivity ◽  
Conservation Priority ◽  
Yellowstone River ◽  
Notropis Stramineus ◽  
High Conservation ◽  
Spatial Linkages

Reduced population connectivity has been implicated as a cause of decreased distributions and abundances of many Great Plains fishes. However, scant empirical evidence quantifying movement and relating the contribution of spatial linkages to population abundances and resilience exists. We used otolith microchemistry analysis to characterize the movements of western silvery minnows (Hybognathus argyritis Girard, 1856), flathead chubs (Platygobio gracilis (Richardson, 1836)), and sand shiners (Notropis stramineus (Cope, 1865)) between the Yellowstone River and its tributaries. Sixty-nine percent of western silvery minnows, 65% of flathead chubs, and 42% of sand shiners moved between the Yellowstone River and tributaries. Mean total number of interchanges was highest among western silvery minnows (4.8 interchanges/mover), intermediate among flathead chubs (4.3 interchanges/mover), and lowest among sand shiners (1.4 interchanges/mover; P < 0.01). Natal movements were rare, but juvenile movements were common and frequent among all three species. Movements between main-stem and tributary habitats are probably prominent facets of the life cycles of other Great Plains minnows. Therefore, connectivity among such habitats should be a high conservation priority to enhance the long-term viability of such fishes.

Empirical Evidence on the Use of Long-Term Performance Plans

2009 ◽  
Author(s):  
Tai-Yuan Chen ◽  
Kai Wai Hui ◽  
Steven R. Matsunaga ◽  
Yong Zhang
Keyword(s):  
Empirical Evidence ◽  
Long Term Performance ◽  
Term Performance

scholarly journals Effect of Barley Sowing Density on the Integrated Weed Management of Lolium rigidum (Annual Ryegrass) in Mediterranean Dryland: A Modeling Approach

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1565
Author(s):  
María Belén D’Amico ◽  
Guillermo R. Chantre ◽  
Guillermo L. Calandrini ◽  
José L. González-Andújar
Keyword(s):  
Weed Management ◽  
Life Cycles ◽  
Integrated Weed Management ◽  
Future Research ◽  
Seed Removal ◽  
Weed Infestation ◽  
High Control ◽  
Weed Dynamics ◽  
The Impact

Population models are particularly helpful for understanding long-term changes in the weed dynamics associated with integrated weed management (IWM) strategies. IWM practices for controlling L. rigidum are of high importance, mainly due to its widespread resistance that precludes chemical control as a single management method. The objective of this contribution is to simulate different IWM scenarios with special emphasis on the impact of different levels of barley sowing densities on L. rigidum control. To this effect, a weed–crop population model for both L. rigidum and barley life cycles was developed. Our results point out: (i) the necessity of achieving high control efficiencies (>99%), (ii) that the increase of twice the standard sowing density of barley resulted in a reduction of 23.7% of the weed density, (iii) non-herbicide-based individual methods, such as delayed sowing and weed seed removal at harvest, proved to be inefficient for reducing drastically weed population, (iv) the implementation of at least three control tactics (seed removal, delay sowing and herbicides) is required for weed infestation eradication independently of the sowing rate, and (v) the effect of an increase in the sowing density is diluted as a more demanding weed control is reached. Future research should aim to disentangle the effect of different weed resistance levels on L. rigidum population dynamics and the required efficiencies for more sustainable IWM programs.

Small-Scale Deliberation and Mass Democracy: A Systematic Review of the Spillover Effects of Deliberative Minipublics

2021 ◽  
pp. 003232172110072
Author(s):  
Ramon van der Does ◽  
Vincent Jacquet
Keyword(s):  
Systematic Review ◽  
Empirical Evidence ◽  
Empirical Research ◽  
Spillover Effects ◽  
Future Research ◽  
Small Scale ◽  
Long Term Effects ◽  
Current Crisis ◽  
Mass Democracy

Deliberative minipublics are popular tools to address the current crisis in democracy. However, it remains ambiguous to what degree these small-scale forums matter for mass democracy. In this study, we ask the question to what extent minipublics have “spillover effects” on lay citizens—that is, long-term effects on participating citizens and effects on non-participating citizens. We answer this question by means of a systematic review of the empirical research on minipublics’ spillover effects published before 2019. We identify 60 eligible studies published between 1999 and 2018 and provide a synthesis of the empirical results. We show that the evidence for most spillover effects remains tentative because the relevant body of empirical evidence is still small. Based on the review, we discuss the implications for democratic theory and outline several trajectories for future research.

scholarly journals Cycles and circulation: a theme in the history of biology and medicine

2021 ◽  
Vol 43 (3) ◽  
Author(s):  
Nick Hopwood ◽  
Staffan Müller-Wille ◽  
Janet Browne ◽  
Christiane Groeben ◽  
Shigehisa Kuriyama ◽  
...  
Keyword(s):  
Natural Philosophy ◽  
Life Cycles ◽  
Modern Times ◽  
Systems Ecology ◽  
The Face ◽  
History Of ◽  
Celestial Bodies ◽  
Reproductive Cycles ◽  
Economics And Biology

AbstractWe invite systematic consideration of the metaphors of cycles and circulation as a long-term theme in the history of the life and environmental sciences and medicine. Ubiquitous in ancient religious and philosophical traditions, especially in representing the seasons and the motions of celestial bodies, circles once symbolized perfection. Over the centuries cyclic images in western medicine, natural philosophy, natural history and eventually biology gained independence from cosmology and theology and came to depend less on strictly circular forms. As potent ‘canonical icons’, cycles also interacted with representations of linear and irreversible change, including arrows, arcs, scales, series and trees, as in theories of the Earth and of evolution. In modern times life cycles and reproductive cycles have often been held to characterize life, in some cases especially female life, while human efforts selectively to foster and disrupt these cycles have harnessed their productivity in medicine and agriculture. But strong cyclic metaphors have continued to link physiology and climatology, medicine and economics, and biology and manufacturing, notably through the relations between land, food and population. From the grand nineteenth-century transformations of matter to systems ecology, the circulation of molecules through organic and inorganic compartments has posed the problem of maintaining identity in the face of flux and highlights the seductive ability of cyclic schemes to imply closure where no original state was in fact restored. More concerted attention to cycles and circulation will enrich analyses of the power of metaphors to naturalize understandings of life and their shaping by practical interests and political imaginations.

Population densities and conservation assessments for three species of chameleons in the Toliara region of south-western Madagascar

2009 ◽  
Vol 30 (3) ◽  
pp. 341-350 ◽  
Author(s):  
Laza Andriamandimbiarisoa ◽  
Christopher Raxworthy ◽  
Kristopher Karsten ◽  
Stanley Fox
Keyword(s):  
Protected Areas ◽  
Conservation Priority ◽  
Population Densities ◽  
Pet Trade ◽  
Anthropogenic Habitats ◽  
Spread F ◽  
Illegal Harvesting ◽  
High Conservation ◽  
Conservation Assessments ◽  
Lower Population

AbstractMadagascar is a high conservation priority. Rainforests receive most of the focus, but the dry deciduous and spiny forests of south-western Madagascar house many endemics, are under high deforestation pressure, and remain largely unprotected. Charismatic vertebrates, like chameleons, face a secondary threat: harvesting for the commercial pet trade. Six chameleons inhabit the arid southwest near Toliara: Furcifer antimena, F. belalandaensis, F. labordi, F. lateralis, F. oustaleti, and F. verrucosus. We measured population densities of three of those species. Furcifer verrucosus has a large distribution, was dense (97.7 ha–1; 95% CI = 60.2-158.6), and inhabited forests and anthropogenic habitats. Furcifer labordi was much less dense (30.8 ha–1; 13.4-70.9), has a restricted range, and has a unique life history that makes it susceptible to perturbations from deforestation or illegal harvesting. Furcifer antimena was the least dense (17.0 ha–1; 9.3-30.9) and has an even smaller distribution range. We lack density data for F. lateralis, but this species was abundant in anthropogenic habitats. Within their respective ranges, there are currently no protected areas for F. antimena and only few for F. labordi; these two species are far less abundant than the more widely spread F. verrucosus. We recommend that high conservation priority be focused on F. antimena and the southern populations of F. labordi due to their restricted distributions, susceptibility to extirpation, lower population densities, and lack of formal protection. Establishing protected areas in the Ranobe region and north of the Fiherenana River, in the Belalanda region, would help protect important populations of these vulnerable species.

Revision of the Pachycondyla wasmannii-group (Hymenoptera: Formicidae)

Zootaxa ◽  
2013 ◽  
Vol 3609 (2) ◽  
pp. 101-141
Author(s):  
JEAN CLAUDE RAKOTONIRINA ◽  
BRIAN L. FISHER
Keyword(s):  
Identification Key ◽  
Conservation Priority ◽  
Key To Species ◽  
Species Limits ◽  
Distribution Maps ◽  
High Conservation

Defining species limits and describing species of ants are important to identify taxa and habitats with elevated diversity in areas of high conservation priority such as the Malagasy region. The Pachycondyla wasmannii-group is revised in the Malagasy region where eight species are recognized, four of which are new: P. masoala sp. n., P. planicornis sp. n., P. tavaratra sp. n., and P. vazimba sp. n. Four species have been previously described: P. cambouei Forel, P. comorensis (André), P. perroti Forel, and P. wasmannii Forel. Pachycondyla perroti admista Forel is newly synonymized under P. perroti. Pachycondyla cambouei is widespread in eastern Madagascar, morphologically variable, and divided into seven morphotypes. An identification key to species and distribution maps are provided for the genus in the Malagasy region. All species are known only from Madagascar except P. wasmannii, which occurs also on Anjouan of the Comoros Islands.

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