Search

Start Over Subject temporal stability

1. Seasonal stability in parasite assemblages of the Brazilian flathead, Percophis brasiliensis (Perciformes: Percophidae): predictable tools for stock identification

Creator:
Braicovich, Paola E. and Timi, Juan T.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
parasite communities, temporal stability, biological tags, fish populations, and south-west Atlantic
Language:
English
Description:
A comparison of the composition and structure of parasite communities of the Brazilian flathead, Percophis brasiliensis Quoy et Gaimard (Perciformes: Percophidae) among seasons during one year was carried out in the Argentine Sea. A total of 195 fish specimens were examined and 25 parasite species were found. Parasite communities in seasonal samples showed a high degree of homogeneity in taxonomic composition and infection levels. Similarity analysis showed that the seasonal stability within and between samples was constant in both the composition and community structure throughout the year. Parasites can, therefore, be considered predictable markers for fish stock identification, independently of the season of capture, at least on an annual scale.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. The role of sampling strategy on apparent temporal stability of soil moisture under subtropical hydroclimatic conditions

Creator:
Gao, Lei , Wang, Yaji , Geris, Josie , Hallett, Paul D., and Peng, Xinhua
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
sampling strategy, subtropical climate, temporal stability, vegetation type, and soil moisture prediction
Language:
Slovak
Description:
Subtropical regions have clay-rich, weathered soils, and long dry periods followed by intense rainfall that produces large fluctuations in soil water content (SWC) and hydrological behavior. This complicates predictions of spatiotemporal dynamics, as datasets are typically collected at too coarse resolution and observations often represent a duration that is too short to capture temporal stability. The aim of the present study was to gain further insights into the role of temporal sampling scale on the observed temporal stability features of SWC order to aid the design of optimal SWC sampling strategies. This focused on both sampling frequency and total monitoring duration, as previous analyses have not considered both of these sampling aspects simultaneously. We collected relatively high resolution data of SWC (fortnightly over 3.5 years) for various soil depths and under contrasting crops (peanuts and citrus) at the red soil region of southeast China. The dataset was split into a three-year training period and a six-month evaluation period. Altogether 13 sampling frequencies (intervals ranging from 15 to 240 days) and eight monitoring duration periods (between three and 36 months) were derived from the training period to identify temporal stability features and the most time stable location (MTSL). The prediction accuracies of these MTSLs were tested using the independent evaluation data. Results showed that vegetation type did affect the spatio-temporal patterns of SWC, whereby the citrus site exhibited a stronger temporal variation and weaker temporal stability than the peanut site. However, the effects of both sampling frequency and observation duration were more pronounced, irrespective of the role of vegetation type or soil depth. With increasing sampling interval or decreasing monitoring duration, temporal stability of SWC was generally overestimated; by less than 10% when sampling interval increased from every 15 to 240 days and by up to 40% with duration decreasing from 36 to 3 months. Our results suggest that sampling strategies and trade-offs between sampling interval and duration should focus on capturing the main variability in hydro-climatological conditions. For subtropical conditions, we found that sampling once every 45 days over 24 months to be the minimum sampling strategy to ensure errors in SWC temporal stability of less than 10%.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

3. Variability of throughfall quantity in a mixed evergreen-deciduous broadleaved forest in central China

Creator:
Su, Lei , Xie, Zongqiang , Xu, Wenting , and Zhao, Changming
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
throughfall, spatial variability, temporal stability, mixed evergreen-deciduous broadleaved forest, and Shennongjia
Language:
Slovak
Description:
Mixed evergreen-deciduous broadleaved forest is the transitional type of evergreen broadleaved forest and deciduous broadleaved forest, and plays a unique eco-hydrologic role in terrestrial ecosystem. We investigated the spatiotemporal patterns of throughfall volume of the forest type in Shennongjia, central China. The results indicated that throughfall represented 84.8% of gross rainfall in the forest. The mean CV (coefficient of variation) of throughfall was 27.27%. Inter-event variability in stand-scale throughfall generation can be substantially altered due to changes in rainfall characteristics, throughfall CV decreased with increasing rainfall amount and intensity, and reached a quasi-constant level when rainfall amount reached 25 mm or rainfall intensity reached 2 mm h–1. During the leafed period, the spatial pattern of throughfall was highly temporal stable, which may result in spatial heterogeneity of soil moisture.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public