Epibenthic gastropods of the middle Florida keys: the role of habitat and environmental stress on assemblage composition

Wood pastures are home to a variety of species, including the dung beetle. Dung beetles are an important functional group in decomposition. Specifically, in terms of livestock manure, they not only contribute to nutrient cycling but are key players in supporting human and animal health. Dung beetles, however, are declining in population, and urgent recommendations are needed to reverse this trend. Recommendations need to be based on solid evidence and specific habitats. Herein, we aimed to investigate the role of an intermediate habitat type between forests and pastures. Wood pastures are key areas for dung beetle conservation. For this reason, we compared dung beetle assemblages among forests, wood pastures, and grasslands. We complemented this with studies on the effects of dung type and season at three Hungarian locations. Pitfall traps baited with cattle, sheep, or horse dung were used in forests, wood pastures, and pasture habitats in spring, summer, and autumn. Dung beetle assemblages of wood pastures showed transient characteristics between forests and pastures regarding their abundance, species richness, Shannon diversity, assemblage composition, and indicator species. We identified a strong effect of season and a weak of dung type. Assemblage composition proved to be the most sensitive measure of differences among habitats. The conservation of dung beetles, and the decomposition services they provide, need continuous livestock grazing to provide fresh dung, as well as the maintenance of wood pastures where dung beetle assemblages typical of forests and pastures can both survive.

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Biogeomorphic feedbacks and the ecosystem engineering of recently deglaciated terrain

Progress in Physical Geography Earth and Environment ◽

10.1177/0309133318816536 ◽

2018 ◽

Vol 43 (1) ◽

pp. 24-45 ◽

Cited By ~ 7

Author(s):

Hannah R Miller ◽

Stuart N Lane

Keyword(s):

Environmental Stress ◽

Ecosystem Engineer ◽

Abiotic Factors ◽

Ecosystem Engineering ◽

Soil Development ◽

Water Dynamics ◽

Biotic Factors ◽

Successional Stage ◽

Abiotic And Biotic Factors

Matthews’ 1992 geoecological model of vegetation succession within glacial forefields describes how following deglaciation the landscape evolves over time as the result of both biotic and abiotic factors, with the importance of each depending on the level of environmental stress within the system. We focus in this paper on how new understandings of abiotic factors and the potential for biogeomorphic feedbacks between abiotic and biotic factors makes further development of this model important. Disturbance and water dynamics are two abiotic factors that have been shown to create stress gradients that can drive early ecosystem succession. The subsequent establishment of microbial communities and vegetation can then result in biogeomorphic feedbacks via ecosystem engineering that influence the role of disturbance and water dynamics within the system. Microbes can act as ecosystem engineers by supplying nutrients (via remineralization of organic matter and nitrogen fixation), enhancing soil development, either decreasing (encouraging weathering) or increasing (binding sediment grains) geomorphic stability, and helping retain soil moisture. Vegetation can act as an ecosystem engineer by fixing nitrogen, enhancing soil development, modifying microbial community structure, creating seed banks, and increasing geomorphic stability. The feedbacks between vegetation and water dynamics in glacial forefields are still poorly studied. We propose a synthesized model of ecosystem succession within glacial forefields that combines Matthews’ initial geoecological model and Corenblit's model to illustrate how gradients in environmental stress combined with successional time drive the balance between abiotic and biotic factors and ultimately determine the successional stage and potential for biogeomorphic feedbacks.

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Abundance of Boeckella gracilis (Daday, 1902) (Copepoda, Calanoida) in seasonal coastal pools in the Araucania region (38°S, Chile)

Crustaceana ◽

10.1163/15685403-00003814 ◽

2018 ◽

Vol 91 (10) ◽

pp. 1211-1217

Author(s):

Patricio De los Ríos

Keyword(s):

Correlation Analysis ◽

Environmental Stress ◽

Relative Abundance ◽

Calanoid Copepod ◽

Inverse Correlation ◽

Inland Waters ◽

Absolute Abundance ◽

Significant Inverse Correlation

Abstract The presence of the calanoid copepod Boeckella gracilis (Daday, 1902) in Chilean seasonal pools has been only poorly studied as yet. The aim of the present study thus is to investigate the role of conductivity and temperature on the relative and absolute abundance of B. gracilis in seasonal coastal pools in the Araucania region (38°S, Chile). The results of correlation analysis revealed the presence of a significant inverse correlation between conductivity and relative abundance, whereas no significant correlations were found between conductivity and absolute abundance, between temperature and absolute abundance, and between temperature and relative abundance. These results agree partially with similar observations for mountain pools in the same region, but they would not agree with observations for calanoids of saline and subsaline inland waters in the northern and southern extremes of Chile. Considering this scenario, the species would show different populational responses to environmental stress in different situations, which phenomenon deserves to be studied more extensively and in more detail.

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The Role of Stress in Interpreting the Dexamethasone Suppression Test

The Canadian Journal of Psychiatry ◽

10.1177/070674379203701009 ◽

1992 ◽

Vol 37 (10) ◽

pp. 724-727 ◽

Cited By ~ 1

Author(s):

Jane Blouin ◽

Eric Spindler ◽

Edgardo Perez ◽

Arthur Blouin ◽

Steven Hotz ◽

...

Keyword(s):

Environmental Stress ◽

Psychological Assessment ◽

Confounding Factor ◽

Dexamethasone Suppression Test ◽

Blood Tests ◽

Routine Administration ◽

Suppression Test ◽

Cortisol Suppression ◽

Dexamethasone Suppression

Stress has been implicated as a major confounding factor in the interpretation of Dexamethasone Suppression Test (DST) results. This study was designed to examine the effects of stress on DST results. Fifty patients with high levels of acute, chronic, and environmental stress participated in the study. Each patient was given a comprehensive psychiatric and psychological assessment, a routine administration of dexamethasone, and blood tests of cortisol values. The results indicate that the three measures of stress do not appear to affect levels of cortisol suppression, however, all three measures of stress predicted depression. As expected, DST cortisol levels were related to depression. Results are discussed in terms of their implications for understanding the associations among stress, depression and DST results.

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