The Role of Top-Down and Bottom-Up Control for Phytoplankton in a Subtropical Shallow Eutrophic Lake: Evidence Based on Long-Term Monitoring and Modeling

For almost 50 years ecologists have debated why herbivores generally don’t increase in numbers to such levels as to deplete or devastate vegetation. One hypothesis is that herbivore populations are regulated at low densities by predators, and a second hypotheses is that plants are fundamentally poor food for herbivores. This has lead to two main hypotheses about the role of herbivores in structuring vegetation: the “bottom-up” and “top-down” hypotheses. Here I survey the literature, with a focus on field experiments designed to investigate the soil resource – vegetation – mammalian herbivore system, specifically asking five questions about how each trophic level responds to (i) resource addition, (ii) vegetation removal, (iii) herbivore removal or reduction, (iv) herbivore addition, and (v) the interaction of resource levels and herbivory? I use these to develop 12 testable predictions. I document the major areas of research as they relate to these 12 predictions, and use these to evaluate weaknesses and limitations in field methods. There are surprisingly few terrestrial studies that conduct factorial manipulations of multiple nutrients or herbivores, even though it is clear that these are essential. Specifically, I argue that a manipulative experimental approach is the most valuable way to advance our theory and understanding, and I advocate the continued use of long-term factorial field experiments that simultaneously manipulate soil resources levels and herbivory (preferably at multiple levels), repeated in a range of environments in which individual species or functional groups are monitored.

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Water quality changes in south-central Ontario lakes and the role of local factors in regulating lake response to regional stressors

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f2011-041 ◽

2011 ◽

Vol 68 (6) ◽

pp. 1038-1050 ◽

Cited By ~ 36

Author(s):

Michelle E. Palmer ◽

Norman D. Yan ◽

Andrew M. Paterson ◽

Robert E. Girard

Keyword(s):

Water Quality ◽

Acidic Deposition ◽

Quality Parameters ◽

Quality Changes ◽

South Central ◽

Chloride Water ◽

Long Term Monitoring ◽

Term Monitoring

The long-term monitoring of eight lakes near Dorset, Ontario, indicates that the water quality has changed significantly over the last 30 years. However, trends in the Dorset lakes may not be representative of changes in other south-central Ontario lakes, as the Dorset lakes are within a small area and span a limited gradient of lake and watershed characteristics. To determine the regional extent of water quality changes, we assessed the chemical changes in 36 diverse lakes that were first sampled between 1981 and 1990 and were resampled in 2004–2005. Similar to trends in the Dorset lakes, changes in the regional lakes included decreasing acidity, calcium, conductivity, metals, and phosphorus, and increasing dissolved organic carbon, nitrogen, sodium, and chloride. Water quality changes were driven by regional stressors, including acidic deposition, climate, and lakeshore residential development. However, stressor-induced responses differed among lakes. Increases in sodium and chloride were greater in developed lakes that were close to winter-maintained roads. Site-specific characteristics, such as lake and watershed morphometry, could not explain heterogeneous changes in the remaining water quality parameters. These results indicate that other factors play an important role in regulating individual lake response to regional stressors.

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Impacts of the non-indigenous seaweed Rugulopteryx okamurae on a Mediterranean coralligenous community (Strait of Gibraltar): The role of long-term monitoring

Ecological Indicators ◽

10.1016/j.ecolind.2020.107135 ◽

2021 ◽

Vol 121 ◽

pp. 107135

Author(s):

Juan Sempere-Valverde ◽

Enrique Ostalé-Valriberas ◽

Manuel Maestre ◽

Roi González Aranda ◽

Hocein Bazairi ◽

...

Keyword(s):

Strait Of Gibraltar ◽

Long Term Monitoring ◽

Term Monitoring

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The Role of Long-Term Monitoring in Diagnosis and Treatment of Epilepsy and Seizure Mimics

The Neuroscience Journal of Shefaye Khatam ◽

10.18869/acadpub.shefa.5.3.62 ◽

2017 ◽

Vol 5 (3) ◽

pp. 62-67

Author(s):

Fereshteh Ghadiri ◽

Ali Gorji ◽

◽

Keyword(s):

Diagnosis And Treatment ◽

Treatment Of Epilepsy ◽

Long Term Monitoring ◽

Term Monitoring

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The role of dynamic testing in design, construction and long-term monitoring of lively footbridges

Footbridge Vibration Design ◽

10.1201/9781482266511-12 ◽

2009 ◽

pp. 81-108

Keyword(s):

Dynamic Testing ◽

Long Term Monitoring ◽

Term Monitoring ◽

Design Construction

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A view of water quality from the Plynlimon watershed

Hydrology and Earth System Sciences ◽

10.5194/hess-1-743-1997 ◽

1997 ◽

Vol 1 (3) ◽

pp. 743-753 ◽

Cited By ~ 46

Author(s):

C. Neal

Keyword(s):

Stream Water ◽

Heterogeneous Systems ◽

Water Acidification ◽

Mixing Processes ◽

Long Term Monitoring ◽

Flow Pathways ◽

Impact Models ◽

Term Monitoring

Abstract. A summary of hydrochemical research in the Plynlimon catchments from 1983 to the present is related to identifying water flow pathways within catchments and the modelling of soil and stream water acidification. The study reveals a highly heterogeneous system that barely conforms with current understanding of hydrology and acidification theory. The role of hydrochemical mixing processes and groundwater flow routing is emphasised as is the need for maintaining long term monitoring studies and enhancing process based studies of water and chemical fluxes through catchments. The applicability of current environmental impact models for predictive and environmental management purposes is questioned and it is proposed that new hydrochemical modelling structures are needed to examine the highly heterogeneous systems being modelled.

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