age class
Recently Published Documents


TOTAL DOCUMENTS

492
(FIVE YEARS 98)

H-INDEX

35
(FIVE YEARS 3)

2021 ◽  
Vol 27 (2) ◽  
Author(s):  
Dawid Jan Sikora

This paper presents the results of a study on the habitat preferences of selected species of the bird community in the Morgi Forest, the Kolbuszowa Forest Division (SE Poland), with the use of the point-stand bird census method. The aim of the study was to test the effectiveness of the method in determining the frequency of colonisation of stands with different habitat parameters by the most abundant bird species. In 270 tree stands of a forest complex with diverse habitats, a bird census was carried out with four counts per each stand. Next, a list of the tree stands and the bird species recorded in the stands was compiled. The stands were divided into categories according to the forest habitat type, dominant species and age class. In the next step, the occurrence frequency of the most abundant bird species was calculated for each stand category. Among the analysed species, the majority showed a positive correlation between the frequency of occurrence and habitat fertility. The influence of the dominant stand species on the occurrence frequency of bird species was largely driven by habitat fertility. The lowest average frequency of the identified avian species was found in stands dominated by pine Pinus sylvestris, birch Betula sp. and black alder Alnus glutinosa. There was generally a positive relationship between age class and the bird community parameters. It is concluded that the point-stand method of bird census provides informative results for research on the habitat selectivity of bird populations.


Author(s):  
Gennadiy G. Terekhov ◽  
◽  
Elena M. Andreeva ◽  
Svetlana K. Stetsenko

The 40-year-old plantations of Siberian stone pine laid out as a permanent seed plot have been studied. The research purpose is to study the integrity, state and main forest inventory parameters of the Siberian stone pine plantations on the southern line of the species range at the end of first age class; to determine the role of natural renewal of trees and shrubs on the development of the Siberian stone pine plantations; to improve process solutions for efficient renewal of high-value biological resources. The research uses the methods generally accepted in forestry, forest science and forest inventory. It is found that the integrity of Siberian stone pine on the site is about 31 % (678 pcs/ha), wherein 406 pcs/ha are without damage to the trunk. Only about 25 % of Siberian stone pine trees grow under low shade, the rest of them are constantly shaded by natural renewal and have varying degrees of suppression. No generative organs were found in 44-year-old Siberian stone pine trees. At the initial stage of plantations growth, the main factor negatively affecting the integrity and state of trees is the damaging of Siberian stone pine by moose. Traditional improvement thinning with leaving stumps that produce many shoots of deciduous species attracts moose to the site in winter, where they use young growth of deciduous species and the covered with needles part of Siberian stone pine as forage. Subsequently, in the absence of tending, natural renewal negatively affects the Siberian stone pine trees, inhibiting growth and formation. It is necessary to remove the negative influence in the mixed biocenosis in order to prevent further deterioration of the Siberian stone pine state. This requires completely different technological solutions for forestry activities such as ringing or injection of trees of natural renewal, causing drying at the root, which significantly reduces or eliminates the emergence of deciduous young growth. This will decrease the attractiveness of the site for moose and minimize their impact on Siberian stone pine. The clear drying of surrounding trees will enhance the illumination of Siberian stone pine crowns and improve their soil nutrition, ensuring good root, trunk, and crown growth and accelerating the beginning of the formation of generative organs. These technical solutions can be used throughout the forest zone for the artificial cultivation of the high-value species – Siberian stone pine. For citation: Terekhov G.G., Andreeva E.M., Stetsenko S.K. Evaluation of Siberian Stone Pine Plantations at the End of the First Age Class. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 56–68. DOI: 10.37482/0536-1036-2021-6-56-68


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sophie E. Watson ◽  
Melissa A. McKinney ◽  
Massimo Pindo ◽  
Matthew J. Bull ◽  
Todd C. Atwood ◽  
...  

AbstractThe gut microbiota may modulate the disposition and toxicity of environmental contaminants within a host but, conversely, contaminants may also impact gut bacteria. Such contaminant-gut microbial connections, which could lead to alteration of host health, remain poorly known and are rarely studied in free-ranging wildlife. The polar bear (Ursus maritimus) is a long-lived, wide-ranging apex predator that feeds on a variety of high trophic position seal and cetacean species and, as such, is exposed to among the highest levels of biomagnifying contaminants of all Arctic species. Here, we investigate associations between mercury (THg; a key Arctic contaminant), diet, and the diversity and composition of the gut microbiota of polar bears inhabiting the southern Beaufort Sea, while accounting for host sex, age class and body condition. Bacterial diversity was negatively associated with seal consumption and mercury, a pattern seen for both Shannon and Inverse Simpson alpha diversity indices (adjusted R2 = 0.35, F1,18 = 8.00, P = 0.013 and adjusted R2 = 0.26, F1,18 = 6.04, P = 0.027, respectively). No association was found with sex, age class or body condition of polar bears. Bacteria known to either be involved in THg methylation or considered to be highly contaminant resistant, including Lactobacillales, Bacillales and Aeromonadales, were significantly more abundant in individuals that had higher THg concentrations. Conversely, individuals with higher THg concentrations showed a significantly lower abundance of Bacteroidales, a bacterial order that typically plays an important role in supporting host immune function by stimulating intraepithelial lymphocytes within the epithelial barrier. These associations between diet-acquired mercury and microbiota illustrate a potentially overlooked outcome of mercury accumulation in polar bears.


2021 ◽  
Author(s):  
Khaldi Zahran ◽  
Nafti Mounir ◽  
Jilani Tabarek

Abstract This study was planned to investigate the raw milk characteristics and quality aspects and to evaluate the impact of nongenetic factors on physicochemical composition and microbial quality of milk from local Maghrebi camels (Camelus dromedarius) kept under a traditional system in oasis areas, southern west, Tunisia. Forty-nine individual milk samples were collected from lactating Negga over two periods of the year (winter and summer). Animals belonging to private flocks were between 5 and 17.5 years of age, with parity numbers ranging from first to sixth. Samples were analyzed for physical parameters, chemical composition, mineral concentrations, and microbiological features according to standard methods. The overall means of physical characteristics were 6.63 ± 0.22, 1030.63 ± 2.54, and 19.11 ± 4.08 for pH, density, and acidity, respectively. No significant association (P > 0.05) between physical characteristics and nongenetic factors has been observed. The average results of chemical composition for dry matter, protein, fat, casein, lactose, ash, and casein/protein ratio were 115.24±15.67g/L, 30.98±6.40 g/L, 32.84±4.88 g/L, 22.77±4.27 g/L, 37.21±4.64 g/L, 6.87±1.59 g/L, and 0.74±0.06 g/L respectively. Season, parity, and age were confirmed to impinge significantly on chemical components, except for lactose. The maximum contents of total solids, protein, casein, and fat content were observed during winter. The third lactation was characterized with the highest content of total solids, protein, casein, and lactose; while the highest fat content was recorded in the second lactation. Lactose content was stable throughout all the studied age classes (P > 0.05), whereas the other chemical constituents, showed an obvious superiority in the age class of 7≤ age ≤ 9 years. Season, parity, and age of the animal exerted a significant effect on all minerals. The highest levels of Ca, P, and K were recorded in the winter (P<0.01) whereas Na showed an opposite pattern and was higher in the summer (P<0.01). All major minerals were higher in milk from multiparous than primiparous camels, with maximum concentrations at the fourth lactation. The uppermost levels of mineral concentrations were recorded in the age class of 7≤ age ≤ 9 years. The lowest ones were those of animals over 12 years old. The microbial analysis of raw milk which is affected by season, parity, and age showed higher overall contamination levels in all studied bacterial counts. The highest levels were observed in winter, among the multiparous and oldest Negga. The results highlighted the complete absence of the two dangerous pathogens Salmonella and CSR in all analyzed samples.


2021 ◽  
Vol 8 (11) ◽  
Author(s):  
Yuri Kawaguchi ◽  
Koyo Nakamura ◽  
Masaki Tomonaga ◽  
Ikuma Adachi

Impaired face recognition for certain face categories, such as faces of other species or other age class faces, is known in both humans and non-human primates. A previous study found that it is more difficult for chimpanzees to differentiate infant faces than adult faces. Infant faces of chimpanzees differ from adult faces in shape and colour, but the latter is especially a salient cue for chimpanzees. Therefore, impaired face differentiation of infant faces may be due to a specific colour. In the present study, we investigated which feature of infant faces has a greater effect on face identification difficulty. Adult chimpanzees were tested using a matching-to-sample task with four types of face stimuli whose shape and colour were manipulated as either infant or adult one independently. Chimpanzees' discrimination performance decreased as they matched faces with infant coloration, regardless of the shape. This study is the first to demonstrate the impairment effect of infantile coloration on face recognition in non-human primates, suggesting that the face recognition strategies of humans and chimpanzees overlap as both species show proficient face recognition for certain face colours.


2021 ◽  
Vol 13 (21) ◽  
pp. 4279
Author(s):  
Amir Arnon ◽  
Serge Landau ◽  
Ido Izhaki ◽  
Dan Malkinson ◽  
Yaniv Levy-Paz ◽  
...  

The populations of the endangered mountain gazelle (Gazella gazella), which inhabit large parts of Israel, across various ecosystems and climatic conditions, shrunk drastically over the last decades. To date, data on gazelle nutrition, how these relate with individual characteristics and respond to seasonal and environmental changes, have not been available. We analyzed 110 samples from gazelle rumen contents collected throughout the country from occasional fatalities, mainly roadkills, and tested the feasibility of using them for near-infrared spectrometry (NIRS) calibrations. Although NIR calibrations for crude protein, in vitro dry matter digestibility, and ash were reasonable, we found that using calibrations based on local forage and feed plant species performed better, and used these to estimate several nutritional constituents in gazelle rumens, using NIRS. We tested how constituents relate to the sex, age-class, and weight of the individual gazelle, and to season and ecosystem type, and found that season plays a major role in gazelle nutrition. Winter is the most propitious season, when crude protein, ash and digestibility are highest, and acid detergent fiber (ADF), neutral detergent fiber (NDF), and the carbon to nitrogen (C:N) ratio are lowest. Autumn, being the harshest season, mirrors winter conditions, and summer and spring show intermediate levels. Yet the relative changes between seasons were mild: about 30%, for crude protein, digestibility, and ash, and 14–22% for ADF, NDF, and C:N ratio. Ecosystem type affected several constituents, and nutrition was slightly better in Mediterranean than in dry ecosystems. Gazelle sex, weight, and age-class had minor effects on nutrition. Overall, it seems that the adaptation of gazelles to their environment is germane to keeping relatively steady nutrition throughout the year. Our results, which do not show a dramatic decline in the quality of gazelle nutrition during any season or among the climatic regions that were studied, suggest that nutrition is not a major driver of the survival of gazelles in the populations surveyed.


PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258397
Author(s):  
Kirsten E. Andersson ◽  
Laura Adamovicz ◽  
Lauren E. Mumm ◽  
Samantha E. Bradley ◽  
John M. Winter ◽  
...  

Baseline plasma electrophoresis profiles (EPH) are important components of overall health and may aid in the conservation and captive management of species. The aim of this study was to establish plasma protein fractions for free-ranging Blanding’s turtles (Emydoidea blandingii) and evaluate differences due to age class (adult vs. sub-adult vs. juvenile), sex (male, female, or unknown), year (2018 vs. 2019), month (May vs. June vs. July), health status, and geographical location (managed vs. unmanaged sites). Blood samples were obtained from 156 Blanding’s turtles in the summer of 2018 and 129 in 2019 at two adjacent sites in Illinois. Results of the multivariate analysis demonstrated that age class, sex, year, month, health status, and geographical location all contributed to the variation observed in free-ranging populations. Adult females had the highest concentration of many protein fractions, likely associated with reproductive activity. Juveniles had lower protein concentrations. Temperature and rainfall differences between years impacted concentrations between 2018 and 2019, while May and June of both years saw higher levels in some protein fractions likely due to peak breeding and nesting season. Individuals with evidence of trauma or disease also showed increased plasma protein fractions when compared to those that were considered healthy. The two sites showed a wide/large variation over the two years. All of these factors emphasize the importance of considering multiple demographic or environmental factors when interpreting the EPH fractions. Establishing ranges for these analytes will allow investigation into disease prevalence and other environmental factors impacting this endangered species.


Author(s):  
Марина Меджидовна Темзокова

Рассматривается микролексика концепта «бзылъфыгъ» (женщина), отражающая этнокультурные смыслы адыгского языка. Материалом исследования послужили данные сплошной выборки из разных типов адыгских словарей и полевые записи. Определяются базовые лексемы, объективирующие концепт, характеризуется состав микролексики ядра и одной из базовых лексем пшъашъэ (девушка). Лексические единицы (ЛЕ) группируются по семи признакам: возрастному, сословному, функциональному статусу женщины/девушки; кровному и некровному родству; в отдельную группу выделены номинанты брачного статуса женщины и представленный в адыгской мифологии женский пантеон богов. Анализируются способы образования слов и словосочетаний, составляющих основу микролексики базовых лексем женщина/девушка . При проведении исследования использовался метод научного наблюдения с дискурсивным анализом. Практическая значимость результатов исследования определяется тем, что они могут быть полезны при дальнейшем рассмотрении когнитивного и лингвокультурного аспектов, как самого концепта «женщина», так и других групп понятий, составляющих концептосферу адыгского языка. This work deals with the microlexics of the concept of " bzylfyg " (woman), reflecting the ethnocultural meanings of the Adygean language. The study was based on data from a continuous sample of different types of Adygean dictionaries and field entries. Basic lexemes that objectify the concept are determined, the composition of the microlexics of the core and one of the basic lexemes - pshashe (girl) - is characterized. Lexical units (LU) are grouped according to seven characteristics: age, class, functional status of a woman/girl; blood and non-blood affinity; the nominees of the marriage status of a woman and the female pantheon of gods represented in Adygean mythology are identified in a separate group. Methods of formation of words and phrases that form the basis of microlexics of basic woman/girl lexemes are analyzed. The study used a scientific observation method with discursive analysis. The practical significance of the results of the study is determined by the fact that they can be useful in further considering the cognitive and linguistic cultural aspects, both of the concept of "woman" itself and other groups of concepts that make up the conceptual atmosphere of the Adygean language.


2021 ◽  
Vol 180 ◽  
pp. 315-328
Author(s):  
Juan M. Lavista Ferres ◽  
Derek E. Lee ◽  
Md Nasir ◽  
Yu-Chia Chen ◽  
Avleen S. Bijral ◽  
...  

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Katherine E. L. Worsley-Tonks ◽  
Stanley D. Gehrt ◽  
Chris Anchor ◽  
Luis E. Escobar ◽  
Meggan E. Craft

Abstract Background Urbanization can have profound effects on ecological interactions. For host–pathogen interactions, differences have been detected between urban and non-urban landscapes. However, host–pathogen interactions may also differ within highly heterogeneous, urbanized landscapes. Methods We investigated differences in infection risk (i.e., probability of infection) within urbanized landscapes using the coyote (Canis latrans) and mosquito-borne nematode, Dirofilaria immitis (the causative agent for canine heartworm), as a case study. We focused on a coyote population in Chicago for which extensive behavioral and heartworm infection data has been collected between 2001 and 2016. Our objectives were to: (i) determine how onset and duration of the heartworm transmission season varied over the 16-year period and across the urban–suburban gradient; and (ii) investigate how heartworm infection risk in coyotes varied over the years, across the urban–suburban gradient, by coyote characteristics (e.g., age, sex, resident status), and coyote use of the urbanized landscape (e.g., use of urban areas, mosquito habitats). Results While onset of the heartworm transmission season differed neither by year nor across the urban–suburban gradient, it was longer closer to the core of Chicago. Of the 315 coyotes sampled, 31.1% were infected with D. immitis. Older coyotes and coyotes sampled in later years (i.e., 2012–2016) were more likely to have heartworm. While coyote location in the urban–suburban gradient was not a significant predictor of infection, the proportion of urban land in coyote home ranges was. Importantly, the size and direction of this association varied by age class. For adults and pups, infection risk declined with urbanization, whereas for subadults it increased. Further, models had a higher predictive power when focusing on resident coyotes (and excluding transient coyotes). The proportion of mosquito habitat in coyote home ranges was not a significant predictor of infection. Conclusions Our findings suggest that urbanization may affect host exposure to vectors of D. immitis, that risk of infection can vary within urbanized landscapes, and that urbanization–wildlife infection associations may only be detected for animals with certain characteristics (e.g., age class and resident status). Graphical abstract


Sign in / Sign up

Export Citation Format

Share Document