Hasil untuk "Ecology"

O. Ovaskainen, G. Tikhonov, A. Norberg et al.

Community ecology aims to understand what factors determine the assembly and dynamics of species assemblages at different spatiotemporal scales. To facilitate the integration between conceptual and statistical approaches in community ecology, we propose Hierarchical Modelling of Species Communities (HMSC) as a general, flexible framework for modern analysis of community data. While non-manipulative data allow for only correlative and not causal inference, this framework facilitates the formulation of data-driven hypotheses regarding the processes that structure communities. We model environmental filtering by variation and covariation in the responses of individual species to the characteristics of their environment, with potential contingencies on species traits and phylogenetic relationships. We capture biotic assembly rules by species-to-species association matrices, which may be estimated at multiple spatial or temporal scales. We operationalise the HMSC framework as a hierarchical Bayesian joint species distribution model, and implement it as R- and Matlab-packages which enable computationally efficient analyses of large data sets. Armed with this tool, community ecologists can make sense of many types of data, including spatially explicit data and time-series data. We illustrate the use of this framework through a series of diverse ecological examples.

N. Dingemanse, Anahita J. N. Kazem, D. Réale et al.

Mark A. Goddard, A. Dougill, T. Benton

J. T. Emlen

J. Ballard, M. Whitlock

J. Odling-Smee, K. Laland, M. Feldman

Ran Nathan, H. Muller‐Landau

Jorge Soberón, A. Peterson

Estimation of the dimensions of fundamental ecological niches of species to predict their geographic distributions is increasingly being attempted in systematics, ecology, conservation, public health, etc. This technique is often (of necessity) based on data comprising records of presences only. In recent years, modeling approaches have been devised to estimate these interrelated expressions of a species' ecology, distributional biology, and evolutionary history—nevertheless, a formal basis in ecological and evolutionary theory has largely been lacking. In this paper, we outline such a formal basis to clarify the use of techniques applied to the challenge of estimating 'ecological niches;' we analyze example situations that can be modeled using these techniques, and clarify interpretation of results.

R. Margalef

M. Csíkszentmihályi, R. Larson, S. Prescott

K. Kershaw

E. W. Jones

A. Longhurst, D. Pauly

Imene Djaalab, Samia Haffaf, Hadria Mansour-Djaalab et al.

Animal Welfare has a significant impact on the dairy cow’s health, behaviour, productivity and milk quality. By implementing husbandry practices that respect the physical, behavioural and emotional needs of dairy cows, the dairy industry can improve the sustainability of its operations and meet rising expectations. The aim of this study is to evaluate the impact of housing systems (free vs. tied) on dairy cow health through musculoskeletal health indicators and lameness scores. The hypothesis that dairy cows reared in free housing have a better quality of health than cows reared in restrained housing is tested. Thus, 300 dairy cows of the Holstein and Montbeliarde breeds were selected from dairy farms in five municipalities of Constantine province (eastern Algeria). The results showed that the frequency of severe lameness did not exceed 12% in stalls with restraints and more than 42% of light lameness are in free-stall housing (<i>p</i> < 0.001). These results reflect a lack of comfort in restricted housing, with an impact on dairy performances. Moreover, the monitoring of lame cows and the functional trimming of their hooves should be frequent. It is also important to implement a cull policy for unproductive cows. Finally, it is very important to provide adequate training to farmers in order to improve the well-being of dairy cows.

Cong Dong, Gordon Huang, Guanhui Cheng et al.

Estimation and analyses of significant wave heights (SWHs) are crucial to climate research, ocean engineering and other applications, with satellite retrieval serving as a fundamental approach. However, few studies attempt to extrapolate SWH models across buoy grids to retrieve ungauged-grid SWHs from multiple altimeters at macroscales, or examine variations of extreme SWHs in relation to climate oscillations, particularly in the Canadian context. To fill these gaps, we develop a macroscale spatially-extrapolative ensemble wave-height retrieval and analysis (MEERA) method to retrieve SWHs from multi-mission satellite altimetry and reveal tempo-spatial characteristics of SWHs means and extremes as well as their variations with climate oscillations. The method is applied across all Canadian waters. According to modeling results, MEERA significantly enhances consistency and accuracy of retrieved SWHs (especially in coastal areas), e.g., reducing biases of conventional methods by over 98%. From 1985 to 2020, waves were strongly seasonal and regional, which drop from winter (1.45 m) to summer (1.17 m) and tend to decline northward. SWHs tend to decrease in mid-eastern regions (e.g., Hudson Bay, Davis Strait and Gulf of St Lawrence) and increase in Canadian Atlantic, Pacific, and Arctic. Across all Canadian waters, climate indices regarding precipitation, e.g., the NBRA (Northeast Brazil Rainfall Anomaly) index, pose the strongest impacts on extreme SWHs compared with others. In Pacific and Atlantic, spatial patterns of winter SWH extremes are associated with negative NAO (North Atlantic Oscillation). El Niño might increase SWHs extremes over the Pacific and Arctic, while decreasing them over mid-eastern regions. This study advances macroscale SWH estimation and analysis, enhancing the understanding of SWH characteristics and their variations across Canada under climate change.

Monika Czop, Joanna Wyczarska-Kokot, Joanna Kalka et al.

A municipal wastewater treatment plant is a complex system of technological devices and facilities designed to remove pollutants from wastewater. The operation of such plants generates a waste stream that can be classified into three types: screenings (code 19 08 01), sand trap contents (code 19 08 02), and stabilized municipal sewage sludge (code 19 08 05). Each generated waste must be managed in accordance with the applicable law. In the context of new business models within the closed-loop economy, wastewater treatment plants are viewed as a resource rich resource that can be used to reclamate degraded lands. The purpose of the study was to evaluate the physicochemical parameters of the waste, which could form the basis for the preparation of soil-forming material. The input material considered was excess digester sludge after the stabilization process, sand from the sand traps, and sand after cleaning the wastewater network. The tested sludge contained 35 % organic substances, 12 % organic carbon, 1.8 % total nitrogen, and 0.24 % potassium. The sand contained about 1 % organic matter, 1.8 % organic carbon, 0.5 % total nitrogen, and 0.02 % potassium. Sand and sludge were prepared in the following mixtures: 1:1, 1:2, 2:1. These mixtures were then assessed for their suitability in the reclamation of degraded areas.

R. Guderian, W. Swank

A. Naess, D. Rothenberg

G. Gooday

M. Allen