Evaluation of an experimental wolf reduction and its impact on deer in Papineau-Labelle Reserve, Quebec

1992 ◽  
Vol 70 (8) ◽  
pp. 1595-1603 ◽  
Author(s):  
François Potvin ◽  
Hélène Jolicoeur ◽  
Laurier Breton ◽  
Rolland Lemieux

From 1984 to 1986, 56 wolves were removed by aerial shooting from two reduction blocks in Papineau-Labelle Reserve: the mean reduction rate was 71% in RB1 and 40% in RB2, compared with 17 and 9% for two untreated blocks (UB1 and UB2). Corresponding mean wolf densities in the four blocks at the end of winter were 0.6, 1.2, 1.6, and 1.7 wolves/100 km2, respectively. Each year, wolf numbers returned to their former level in the subsequent winter in RB1, mainly through immigration. Three blocks were each associated with a large deer wintering area containing 1400–1700 animals before the wolf reduction. The deer yard in RB1 reached a population of 4200 deer, a 1.32% finite rate of increase per year, compared with annual rates of 1.15–1.18% in UB1 and RB2. The harvest of bucks was not affected by the wolf reduction. The number of fawns per 100 does in the harvest was higher in RB1 than in UB1 in 1985 and 1986. We do not recommend wolf reduction as a management tool in the current context, as deer numbers increased markedly, even where no control was applied, as a consequence of mild winters.

2020 ◽  
Vol 25 (8) ◽  
pp. 1461-1471
Author(s):  
Lixia Xie ◽  
Na Zhang ◽  
Xinran Wu ◽  
Kai Liu ◽  
Chenlin Liu ◽  
...  

Lasioseius japonicus is a species of soil-dwelling predatory mite with great potential for controlling insect pests and has a broad application prospect in biological control. This study was conducted under indoor conditions to explore the development, survival and reproduction of L. japonicus on two diets. Through the construction of two-sex life table of L. japonicus, it was revealed that, when it preyed on eggs of Drosophila melanogaster, the intrinsic rate of increase (r) was 0.2614 d-1, the net reproductive rate (R0) was 57.76 offspring, the finite rate of increase (λ) was 1.2988 d-1, and the mean generation time (T) was 15.49 d. When preying on eggs of Sitotroga cerealella, the intrinsic rate of increase (r) of L. japonicus was 0.1560 d-1, the net reproductive rate (R0) was 20.96 offspring, the finite rate of increase (λ) was 1.1690d-1, and the mean generation time (T) was 19.41 d. In addition, the life expectancy and population growth trend of L. japonicus were simulated based on the above two alternative prey species. The results showed that feeding on the eggs of D. melanogaster is more beneficial to the growth and reproduction of L. japonicus.


2019 ◽  
Vol 79 (3) ◽  
pp. 488-494 ◽  
Author(s):  
A. Specht ◽  
V. F. Roque-Specht

Abstract In this study we evaluate the biotic potential and reproductive parameters of Spodoptera cosmioides (Walker, 1858) under controlled conditions (25 ± 1 °C, 70 ± 10% RH and 14 hour photophase). Females, on average, (14.433 days) did not live significantly longer than their male counterparts (13.100 days). The mean durations of the pre-oviposition, oviposition and post-oviposition periods were 2.767, 10.600 and 1.067 days, respectively. The mean fecundity of females was 5,073.533 eggs and the mean fertility was 5,021.027 larvae. On average, females copulated 1.167 times. Fecundity was positively correlated with the number of copulations (r = 0.583, P <0.001). The number of copulations, however, was negatively correlated whit the duration of the pre-oviposition (r = -0.560, P = 0.007) and oviposition (r = -0.479, P = 0.048) periods, and overall longevity (r = -0.512, P = 0.031). The biotic potential was estimated at 6.547 x 1021 individuals/female/year. The net reproductive rate (Ro) was 2,193.722 times per generation and the mean generation time (T) was 46.407 days. The intrinsic rate of increase (rm) was 0.166, with a finite rate of increase (λ) of 1.180, per week.


2000 ◽  
Vol 78 (5) ◽  
pp. 764-776 ◽  
Author(s):  
André Dumont ◽  
Michel Crête ◽  
Jean-Pierre Ouellet ◽  
Jean Huot ◽  
Jean Lamoureux

We studied white-tailed deer (Odocoileus virginianus borealis) at the northeastern limit of their range after their density had decreased as a result of harsh winters aggravated by coyote predation. We compared two populations wintering in adjacent areas. In the Lac Témiscouata wintering area (LTWA), deer and browse density averaged 10 animals/km2 and 127 000 deciduous twigs/ha compared with 20 deer/km2 and 68 000 twigs/ha, respectively, at the Pohénégamook wintering area (PWA). For 75 radio-collared deer, the probability of death was highest during the short spring migration and remained elevated in winter, whereas fewer deaths occurred in summer and none during autumn migration. PWA deer had a higher mortality rate than did LTWA animals and died mostly in winter, from predation, starvation, and collision equally. Based on observed survival rates, we estimated that the finite rate of increase averaged [Formula: see text]1.25 and [Formula: see text]1.00 for LTWA and PWA populations, respectively. At PWA, we examined 129 carcasses to determine the mortality pattern of deer. Among adults, we did not detect significant differences related to sex. Starvation and predation affected more fawns and old deer than prime animals, whereas collision appeared to be nonselective. Most cases of starvation occurred after the beginning of March, when body reserves dropped to low levels. We conclude that competition for winter forage regulated PWA deer during the study.


REVISTA FIMCA ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 28-31
Author(s):  
Darlan Darlan Sanches Barbosa Alves ◽  
Victor Mouzinho Spinelli ◽  
Marcos Santana Moraes ◽  
Carolina Augusto De Souza ◽  
Rodrigo da Silva Ribeiro ◽  
...  

Introdução: O estado de Rondônia se destaca como tradicional produtor de café, sendo o segundo maior produtor brasileiro de C. canephora. No melhoramento genético de C. canephora, a seleção de plantas de elevada peneira média está associada à bebida de qualidade superior. Objetivos: O objetivo desse estudo foi avaliar a variabilidade genética de clones de C. canephora para o tamanho dos grãos, mensurado a partir da avaliação da peneira média (PM). Materiais e Métodos: Para isso, foi conduzido ao longo de dois anos agrícolas experimento no campo experimental da Embrapa no município de Ouro Preto do Oeste-RO, para a avaliação da peneira média de 130 genótipos (clones) com características das variedades botânicas Conilon, Robusta e híbridos intervarietais. O delineamento experimental utilizado foi de blocos ao acaso, com quatro repetições de quatro plantas por parcela. Resultados: Não houve resultados significativos para a interação clones X anos, indicando uma maior consistência no comportamento das plantas ao longo do tempo. Porém foram observadas diferenças significativas para o tamanho dos grãos entre os genótipos avaliados, possibilitando selecionar genótipos superiores. Conclusão: Os genótipos agruparam-se em cinco classes de acordo com o teste de média, subsidiando a caracterização de um gradiente de variabilidade da característica avaliada ABSTRACTIntroduction: Coffea canephora accounts for approximately 35% of the world's coffee production. The state of Rondônia stands out as a traditional coffee producer, being the second largest Brazilian producer of C. canephora. In the classical genetic improvement of C. anephora, the selection of plants of high average sieve is associated with a drink of superior quality. Objectives: The objective of this udy was to evaluate the genetic variability of Coffea canephora clones for the agronomic medium sieve (PM). Materials and Methods: The experiment was conducted in the experimental field of Embrapa, municipality of OuroPreto do Oeste-RO, located at coordinates 10º44'53 "S and 62º12'57". One hundred thirty genotypes (clones) of botanical characteristics Conilon, Robusta and intervarietal hybrids were evaluated in the agricultural years 2013-2014 and 2014-2015. The experimental design was a randomized block design with four blocks and four plants per plot, spacing 3.5 x 1.5 meters between plants. Results: Significant difference was found for the grain size. According to the F test, at 5% probability, the genotypes were grouped into five classes according to the mean test. Conclusion: The results obtained subsidized the characterization of a variability gradient of the evaluated trait.


2015 ◽  
Vol 08 (04) ◽  
pp. 1550012 ◽  
Author(s):  
Qinqin Zhang ◽  
Maureen Neitz ◽  
Jay Neitz ◽  
Ruikang K. Wang

Purpose: To provide a geographical map of choroidal thickness (CT) around the macular region among subjects with low, moderate and high myopia. Methods: 20 myopic subjects (n = 40 eyes) without other identified pathologies participated in this study: 20 eyes of ≤ 3 diopters (D) (low myopic), 10 eyes between -3 and -6D (moderate myopic), and 10 eyes of ≥ 6D (high myopic). The mean age of subjects was 30.2 years (± 7.6 years; range, 24 to 46 years). A 1050 nm spectral-domain optical coherence tomography (SD-OCT) system, operating at 120 kHz imaging rate, was used in this study to simultaneously capture 3D anatomical images of the choroid and measure intraocular length (IOL) in the subject. The 3D OCT images of the choroid were segmented into superior, inferior, nasal and temporal quadrants, from which the CT was measured, representing radial distance between the outer retinal pigment epithelium (RPE) layer and inner scleral border. Measurements were made within concentric regions centered at fovea centralis, extended to 5 mm away from fovea at 1 mm intervals in the nasal and temporal directions. The measured IOL was the distance from the anterior cornea surface to the RPE in alignment along the optical axis of the eye. Statistical analysis was performed to evaluate CT at each geographic region and observe the relationship between CT and the degree of myopia. Results: For low myopic eyes, the IOL was measured at 24.619 ± 0.016 mm. The CT (273.85 ± 49.01 μm) was greatest under fovea as is in the case of healthy eyes. Peripheral to the fovea, the mean CT decreased rapidly along the nasal direction, reaching a minimum of 180.65 ± 58.25μm at 5 mm away from the fovea. There was less of a change in thickness from the fovea in the temporal direction reaching a minimum of 234.25 ± 42.27 μm. In contrast to the low myopic eyes, for moderate and high myopic eyes, CTs were thickest in temporal region (where CT = 194.94 ± 27.28 and 163 ± 34.89 μm, respectively). Like the low myopic eyes, moderate and high myopic eyes had thinnest CTs in the nasal region (where CT = 100.84 ± 16.75 and 86.64 ± 42.6μm, respectively). High myopic eyes had the longest mean IOL (25.983 ± 0.021mm), while the IOL of moderate myopia was 25.413 ± 0.022 mm (**p < 0.001). The CT reduction rate was calculated at 31.28 μm/D (diopter) from low to moderate myopia, whilst it is 13.49 μm/D from moderate to high myopia. The similar tendency was found for the IOL reduction rate in our study: 0.265 mm/D from low to moderate myopia, and 0.137 mm/D from moderate to high myopia. Conclusion: The CT decreases and the IOL increases gradually with the increase of myopic condition. The current results support the theory that choroidal abnormality may play an important role in the pathogenesis of myopic degeneration.


2018 ◽  
Vol 18 (4) ◽  
Author(s):  
Maria Isabel Carvalho Gonçalves ◽  
Renata Santoro de Sousa-Lima ◽  
Niel Nascimento Teixeira ◽  
Gustavo Henrique Carvalho ◽  
Daniel Danilewicz ◽  
...  

Abstract: The population of humpback whales from breeding stock A is increasing, and little is known about the routes used by humpbacks that move north of the main calving area of Brazil, the Abrolhos Bank. The aim of this study was to describe the movements of humpback whales in a reoccupation wintering area (Serra Grande, Bahia state, Brazil) based on land-based surveys to test if movement patterns change during the season and between years, due to group composition, behavioral state, and distance to the coast. The mean leg speed of the groups sighted was 6.88 (±2.92) km/h, and leg speed was positively correlated with distance to the coast. There was an increase in leg speed and distance to the coast with increasing number of escorts in the groups with calves. The mean linearity value for group trajectory was 0.81 (±0.19) and the mean reorientation rate was 25.72 (±19.09) º/min. We observed a predominance of trajectories heading south throughout the study. Groups exhibiting more erratic movements early in the season, and groups moving south showed more linear trajectories than groups moving north, indicating the beginning of their migration back to the feeding grounds. Energy conserving strategies and social context affect the movements of humpback whales in Serra Grande, resulting in the observed patterns of the reoccupation of available and suitable habitat north of Abrolhos. Thereby, special attention should be given managing activities with the potential to disturb or displace whales using the region to calve and breed.


2018 ◽  
Vol 35 (04) ◽  
pp. 306-314 ◽  
Author(s):  
Yoshichika Yasunaga ◽  
Daisuke Yanagisawa ◽  
Erika Ohata ◽  
Kiyoshi Matsuo ◽  
Shunsuke Yuzuriha

Background Although lymphedema is fundamentally abnormal accumulation of excess water in the extracellular space, previous studies have evaluated the efficacy of physiological bypass surgery (lymphaticovenular anastomosis [LVA]) for lymphedema without measuring water volume. This study clarified the water reductive effect of LVA using bioelectrical impedance analysis (BIA). Methods The efficacy of LVA for unilateral lower-limb lymphedema was evaluated using BIA in a retrospective cohort. The water volume of affected and unaffected legs was measured using multifrequency BIA before and after LVA. Preoperative measurements were undertaken after compression therapy for at least 3 months. The follow-up period after LVA was a minimum of 6 months. Results Thirty consecutive patients with unilateral lower-limb lymphedema were enrolled. The mean water volume reduction of the affected leg by LVA (ΔLBW) was 0.86 L (standard deviation [SD]: 0.86, median: 0.65) with a mean number of 3.3 anastomoses (SD: 1.7). The mean reduction rate of edema was 45.1% (SD: 36.3). Multiple linear regression analysis revealed water volume difference between the affected and unaffected legs before LVA (excess LBW) as the strongest predictor of ΔLBW (R 2 = 0.759, p < 0.01; β = 0.500, p < 0.01). Conclusion The LVA reduces the volume of accumulated body water in lower-limb lymphedema. As excess LBW most strongly predicted the amount of water volume reduction by LVA, body water volume measurement by BIA before LVA might identify patients with low excess LBW not expected to benefit from LVA, regardless of apparent differences in limb circumference.


PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0250311
Author(s):  
Aonan Zhang ◽  
Lin Zhu ◽  
Zhenghao Shi ◽  
Tianying Liu ◽  
Lanlan Han ◽  
...  

The soybean aphid Aphis glycines Matsumura (Hemiptera: Aphididae) is a primary pest of soybeans and poses a serious threat to soybean production. Our studies were conducted to understand the effects of different concentrations of insecticides (imidacloprid and thiamethoxam) on A. glycines and provided critical information for its effective management. Here, we found that the mean generation time and adult and total pre-nymphiposition periods of the LC50 imidacloprid- and thiamethoxam-treatment groups were significantly longer than those of the control group, although the adult pre-nymphiposition period in LC30 imidacloprid and thiamethoxam treatment groups was significantly shorter than that of the control group. Additionally, the mean fecundity per female adult, net reproductive rate, intrinsic rate of increase, and finite rate of increase of the LC30 imidacloprid-treatment group were significantly lower than those of the control group and higher than those of the LC50 imidacloprid-treatment group (P < 0.05). Moreover, both insecticides exerted stress effects on A. glycines, and specimens treated with the two insecticides at the LC50 showed a significant decrease in their growth rates relative to those treated with the insecticides at LC30. These results provide a reference for exploring the effects of imidacloprid and thiamethoxam on A. glycines population dynamics in the field and offer insight to agricultural producers on the potential of low-lethal concentrations of insecticides to stimulate insect reproduction during insecticide application.


Acarologia ◽  
2018 ◽  
Vol 58 (1) ◽  
pp. 52-61
Author(s):  
Samah Ben Chaaban ◽  
Brahim Chermiti ◽  
Serge Kreiter

The old world date mite Oligonychus afrasiaticus is an important spider mite pest of the date palms Phoenix dactylifera L. mostly in North Africa and the Middle East. A population of the predaceous mite Typhlodromus (Anthoseius) athenas has been recently found in Tunisia in association with a decrease of O. afrasiaticus densities. The objective of this paper was to assess the development and reproduction abilities of T. ( A.) athenas on O. afrasiaticus under laboratory conditions at two temperatures: 27 and 32 °C. The results obtained show that females of T. (A.) athenas develop in 5 days at 27 °C and 4.1 days at 32 °C. The mean fecundity of T. (A.) athenas was 32.1 and 23.2 eggs per female at 27 and 32 °C, respectively. Life table parameters were stimated: the net reproductive rate (Ro) 27.9 and 17.9 eggs/female, the intrinsic rate of increase (rm) 0.322 and 0,344 female/female/day and the mean generation time (T) 10.3 and 8.4 days at 27 and 32 °C, respectively. At both temperatures tested, T. (A.) athenas intrinsic rate of increase was greater than that of O. afrasiaticus (rm = 0.213 at 32 °C,against rm = 0.166 day1 at 27 °C). Typhlodromus (A.) athenas would be able to develop at a wide range of temperatures feeding on O. afrasiaticus and seems to be able to potentially control it.


2021 ◽  
Vol 2 (4) ◽  
pp. 5378-5394
Author(s):  
Viteri Valle Victor Vicente ◽  
José Luis Domínguez Caiza ◽  
Carmita del Rocío Sánchez Verdezoto ◽  
González León Pablo Oswaldo

El presente trabajo de investigación fue realizado en el año 2020 y 2021, durante la pandemia del COVID-19, es importante hacer esta puntualización puesto que la educación universitaria por años obvió la enseñanza virtual, utilizando las plataformas web como un método optativo al principio, sin embargo, dentro del contexto actual pasaron a ser obligatorias. En este punto del resumen se tiene que aclarar que la herramienta de gestión de aprendizaje, o LMS con el que se trabajo es el Moodle. Es por ello, que fue lanzada a mediados del año 2020 al entorno virtual para los procesos educativos permitiendo una mejor comunicación relativamente entre participantes, también para el desarrollo colectivo e individual del aprendizaje, y siendo parte de ello, la evaluación. La evaluación de los estudiantes es una etapa crítica del proceso educativo, puesto que si es de bajo nivel los estudiantes serán aprobados sin que hayan asimilado los conocimientos mínimos, por el contrario, si es muy estricta probablemente un porcentaje elevado de estudiantes no aprobarían la materia. Por otra parte, el hecho de que los alumnos manejen muy bien las herramientas tecnológicas de esta época provoca que los docentes se sientan presionados durante el proceso de evaluación, puesto que la posibilidad de que los estudiantes se vean tentados a ver las pruebas individuales como evaluaciones colaborativas (grupales) aumenta considerablemente. ¿Cómo han tratado los docentes de inmunizar (usando terminología de estos días) nuestras evaluaciones contra esta posibilidad?, el arsenal de opciones con el que viene equipado el LMS Moodle es variado, se requiere valorar la potencia del tipo de pregunta calculada a la luz del tema que se quiere evaluar, sobre el nivel educativo (que es el  universitario), el ciclo en el que se encuentran nuestros estudiantes (al principio de sus carreras, en la mitad o finalizando), los pre-requisitos que tiene la asignatura y finalmente la capacidad que se tenga para poder implementar las preguntas. Lo que se pretende hacer en este artículo es compartir como se han implementado preguntas calculadas, generadas aleatoriamente para evaluar el tema específico del cálculo de monto, dentro del capítulo de Interés Simple de un curso de Matemáticas Financieras utilizando preguntas calculadas que son generadas a partir de un conjunto de datos que se pueden especificar.   To contextualize, this article was written in 2021 during the COVID-19 pandemic, it is important to make this point since university education for years obviated virtual teaching, using web platforms as an optional method at the beginning, however, within the current context they became mandatory. At this point in the summary, we have to clarify that the learning management tool, or LMS with which we work is Moodle. That is why it was launched in mid-2020 to the virtual environment for educational processes, allowing relatively better communication between participants, also for the collective and individual development of learning, and being part of it, evaluation. The evaluation of students is a critical stage of the educational process, since if it is of a low level, students will be approved without having assimilated the minimum knowledge, on the contrary, if it is very strict, a high percentage of students would probably not pass the subject. On the other hand, the fact that students handle the technological tools of this time very well causes teachers to feel pressured during the evaluation process, since the possibility that students are tempted to see individual tests as evaluations collaborative (group) increases considerably. How have we teachers tried to immunize (using terminology of these days) our evaluations against this possibility? The arsenal of options with which the LMS Moodle is equipped is varied, we need to assess the power of the type of question calculated in light of the subject that we want to evaluate, on the educational level (which is university), the cycle in which our students are (at the beginning of their careers, in the middle or at the end), the prerequisites that the subject has and finally the capacity that we have to be able to implement the questions. What we intend to do in this article is to share how we have implemented calculated questions, randomly generated to evaluate the specific topic of calculating the amount, within the Simple Interest chapter of a Financial Mathematics course using calculated questions that are generated from a set of data that we can specify.


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