Prairie Chicken Responses to Changing Booming-Ground Cover Type and Height

1969 ◽  
Vol 33 (3) ◽  
pp. 636 ◽  
Author(s):  
Raymond K. Anderson
2018 ◽  
Vol 10 (12) ◽  
pp. 2018 ◽  
Author(s):  
Ying She ◽  
Reza Ehsani ◽  
James Robbins ◽  
Josué Nahún Leiva ◽  
Jim Owen

Frequent inventory data of container nurseries is needed by growers to ensure proper management and marketing strategies. In this paper, inventory data are estimated from aerial images. Since there are thousands of nursery species, it is difficult to find a generic classification algorithm for all cases. In this paper, the development of classification methods was confined to three representative categories: green foliage, yellow foliage, and flowering plants. Vegetation index thresholding and the support vector machine (SVM) were used for classification. Classification accuracies greater than 97% were obtained for each case. Based on the classification results, an algorithm based on canopy area mapping was built for counting. The effects of flight altitude, container spacing, and ground cover type were evaluated. Results showed that container spacing and interaction of container spacing with ground cover type have a significant effect on counting accuracy. To mimic the practical shipping and moving process, incomplete blocks with different voids were created. Results showed that the more plants removed from the block, the higher the accuracy. The developed algorithm was tested on irregular- or regular-shaped plants and plants with and without flowers to test the stability of the algorithm, and accuracies greater than 94% were obtained.


Author(s):  
Marybeth Lorbiecki

The windswept wastelands of the Dust Bowl made it clear to many Americans how fragile the human place in nature is. Suddenly, schools across the country wanted to teach conservation, erosion prevention, and wildlife management. Letters piled up on Leopold’s desk, asking his advice. Leopold replied with a list of resources, but his overriding message was that nature was the best teacher. At fifty-one, Leopold had seven graduate students and a full flock of undergraduates. With a blend of affection and awe, they called him “the Professor.” Marie McCabe, the wife of graduate student Robert McCabe, was quite surprised when she first met the Professor. “I had expected him to be a combination of Abe Lincoln and Thomas Jefferson. Here he was, extremely gracious, but of ordinary size and appearance, not at all handsome … showing no sign of being an author and absolute authority on everything.” Game Management 118 had become a campus favorite. Robert S. Ellarson, a Leopold wildlifer, recalled his first meeting: “The class had assembled before the Professor arrived. Soon the clicking of steel-cleated heels signalled his approach. When he arrived and stood before the class, I was impressed by the bold, virile, almost macho appearance of the man. And I was absolutely enthralled by the lecture that followed.” On Saturdays, the class traveled to the arboretum (which was slowly growing toward a natural state) or to various research plots. In the field, Leopold pointed out such elements as animal tracks and rubbings, scat, browsed plants, nests and burrows, gullies and runoff tracks, ground cover and foliage, and rock formations. Then he asked questions, pushing the students to put together the signs they had seen, to draw for themselves a recent and not-so-recent history of the plot of land: . . . Look at the trees in the yard and the soil in the field and tell us whether the original settler carved his farm out of prairie or woods. Did he eat prairie chicken or wild turkey for his Thanksgiving? What plants grew here originally which do not grow here now? Why did they disappear? What did the prairie plants have to do with creating the corn-yielding capacity of this soil? Why does this soil erode now but not then?. . .


2014 ◽  
Vol 30 (3) ◽  
pp. 372-381 ◽  
Author(s):  
X. Morvan ◽  
C. Naisse ◽  
O. Malam Issa ◽  
J. F. Desprats ◽  
A. Combaud ◽  
...  

Parasitology ◽  
2001 ◽  
Vol 122 (5) ◽  
pp. 507-513 ◽  
Author(s):  
R. J. EISEN ◽  
N. M. WRIGHT

In a 3-year study, we examined landscape features (aspect, slope, sun exposure, canopy cover, type of ground cover, and nearest water source) that were potentially related to prevalence of infection withPlasmodium mexicanumin fence lizards (Sceloporus occidentalis) within a 4.5 ha study area in northern California, USA. Logistic regression analysis showed that ground cover type was the primary mediator of the probability ofP. mexicanuminfection. Infected lizards were captured more often in rock and/or leaf litter locations than in grassy ones. In another experiment, the study area was divided into 9 sites (0.07–0.33 ha), and infection prevalence was calculated for each. Three sites with high (>30%) infection prevalence had significantly more rocky outcrops and leaf litter than those with low (<20%) or moderate (20–30%) infection prevalence (N= 3 sites each). We conclude that lizard site selection may influence the probability of exposure to infected vectors and thus the likelihood ofP. mexicanuminfection. We also demonstrate that studies at different spatial scales may be required to understand fully the relationship between landscape features and parasite distribution.


Author(s):  
Marco, A. Márquez-Linares ◽  
Jonathan G. Escobar--Flores ◽  
Sarahi Sandoval- Espinosa ◽  
Gustavo Pérez-Verdín

Objective: to determine the distribution of D. viscosa in the vicinity of the Guadalupe Victoria Dam in Durango, Mexico, for the years 1990, 2010 and 2017.Design/Methodology/Approach: Landsat satellite images were processed in order to carry out supervised classifications using an artificial neural network. Images from the years 1990, 2010 and 2017 were used to estimate ground cover of D. viscosa, pastures, crops, shrubs, and oak forest. This data was used to calculate the expansion of D. viscosa in the study area.Results/Study Limitations/Implications: the supervised classification with the artificial neural network was optimal after 400 iterations, obtaining the best overall precision of 84.5 % for 2017. This contrasted with the year 1990, when overall accuracy was low at 45 % due to less training sites (fewer than 100) recorded for each of the land cover classes.Findings/Conclusions: in 1990, D. viscosa was found on only five hectares, while by 2017 it had increased to 147 hectares. If the disturbance caused by overgrazing continues, and based on the distribution of D. viscosa, it is likely that in a few years it will have the ability to invade half the study area, occupying agricultural, forested, and shrub areas


2004 ◽  
Vol 155 (7) ◽  
pp. 284-289 ◽  
Author(s):  
Pietro Stanga ◽  
Niklaus Zbinden

The retrospective study based on aerial photos (1971–2001) of the Canton Tessin made it possible to measure and analyze the evolution of the vegetation of eleven Alpine zones. The analysis shows a strong expansion of the arborescent vegetation and, at the same time, a decrease in other forms of ground cover (bush, shrub, meadow and unproductive spaces). Analysis of the data gives rise to the conjecture that the strong evolutionary dynamism evidenced by the areas under investigation is a result of the vast clearings carried out in past centuries to create pastures. Following the subsequent decrease in human pressure, nature today is attempting to rebalance the level of the biomass. These processes manifest themselves in different ways and with various intensity, depending on the interaction of numerous factors (e.g. climatic conditions, site fertility, initial conditions, evolution of anthropological pressure, etc.).


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