scholarly journals Predation control of zooplankton dynamics: a review of observations and models

2013 ◽  
Vol 71 (2) ◽  
pp. 254-271 ◽  
Author(s):  
Ute Daewel ◽  
Solfrid Sætre Hjøllo ◽  
Martin Huret ◽  
Rubao Ji ◽  
Marie Maar ◽  
...  

Abstract Daewel, U., Hjøllo, S. S., Huret, M., Ji, R., Maar, M., Niiranen, S., Travers-Trolet, M., Peck, M. A., van de Wolfshaar, K. E. 2014. Predation control of zooplankton dynamics: a review of observations and models. – ICES Journal of Marine Science, 71: 254–271. We performed a literature review to examine to what degree the zooplankton dynamics in different regional marine ecosystems across the Atlantic Ocean is driven by predation mortality and how the latter is addressed in available modelling approaches. In general, we found that predation on zooplankton plays an important role in all the six considered ecosystems, but the impacts are differently strong and occur at different spatial and temporal scales. In ecosystems with extreme environmental conditions (e.g. low temperature, ice cover, large seasonal amplitudes) and low species diversity, the overall impact of top-down processes on zooplankton dynamics is stronger than for ecosystems having moderate environmental conditions and high species diversity. In those ecosystems, predation mortality was found to structure the zooplankton mainly on local spatial and seasonal time scales. Modelling methods used to parameterize zooplankton mortality range from simplified approaches with fixed mortality rates to complex coupled multispecies models. The applicability of a specific method depends on both the observed state of the ecosystem and the spatial and temporal scales considered. Modelling constraints such as parameter uncertainties and computational costs need to be balanced with the ecosystem-specific demand for a consistent, spatial-temporal dynamic implementation of predation mortality on the zooplankton compartment.

Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 78
Author(s):  
Jessica M. Quinton ◽  
Johan Östberg ◽  
Peter N. Duinker

Research Highlights: A large body of research highlighted the important contributions that urban forests make to cities and their inhabitants. However, our urban forests face threats from issues such as rapid urbanization, climate change, and the spread of pests and diseases. As such, proactive and effective management is necessary to ensure their long-term sustainability. Given the multiple spatial and temporal scales on which threats can arise, effective management needs to account for these scales and adjust accordingly. The degree to which this currently happens is unclear. Background and Objectives: The aim of this study was to determine the role of multi-scale management in urban forestry, using cemeteries in Malmö, Sweden as a case study. Cemeteries can provide extensive tree canopy but are not readily considered in urban forest management. We sought to determine (1) the threats to the current cemetery tree populations, (2) the extent of multi-scale cemetery tree management, (3) whether tree management plans promote multi-scale management, and (4) how cemetery tree management can be improved. Materials and Methods: Malmö cemetery tree inventories were analyzed with respect to size class and species diversity. Existing cemetery tree management plans were examined to determine the spatial and temporal scales of their recommendations. Interviews were conducted with cemetery managers to determine management priorities and actions. Results: We found that cemetery tree populations in Malmö suffer from a lack of age class and species diversity. Management tends to occur on short time scales and efforts focus mainly on addressing individual trees, although some consideration is given to large-scale species diversification. The management plans previously created for these cemetery trees make recommendations for age class and species diversification but are yet to be used extensively by cemetery managers. Conclusions: The long-term stability of Malmö’s cemetery tree populations is threatened by a lack of species and age diversity. Current management efforts emphasize addressing small-scale issues. Although there is a desire to improve species diversity, this can cause conflict with existing cultural values.


2021 ◽  
Vol 14 (4) ◽  
Author(s):  
Zarai Besma ◽  
Walter Christian ◽  
Michot Didier ◽  
Montoroi Jean Pierre ◽  
Hachicha Mohamed

2008 ◽  
Vol 1 (2) ◽  
pp. 81-88 ◽  
Author(s):  
C. Zevenbergen ◽  
W. Veerbeek ◽  
B. Gersonius ◽  
S. Van Herk

2015 ◽  
Vol 120 ◽  
pp. 51-60 ◽  
Author(s):  
Yuval ◽  
Meytar Sorek–Hamer ◽  
Amnon Stupp ◽  
Pinhas Alpert ◽  
David M. Broday

Hydrobiologia ◽  
2008 ◽  
Vol 611 (1) ◽  
pp. 1-4 ◽  
Author(s):  
A. Razinkovas ◽  
Z. Gasiūnaitė ◽  
P. Viaroli ◽  
J. M. Zaldívar

2015 ◽  
Vol 19 (8) ◽  
pp. 3541-3556 ◽  
Author(s):  
M. Majerova ◽  
B. T. Neilson ◽  
N. M. Schmadel ◽  
J. M. Wheaton ◽  
C. J. Snow

Abstract. Beaver dams affect hydrologic processes, channel complexity, and stream temperature in part by inundating riparian areas, influencing groundwater–surface water interactions, and changing fluvial processes within stream systems. We explored the impacts of beaver dams on hydrologic and temperature regimes at different spatial and temporal scales within a mountain stream in northern Utah over a 3-year period spanning pre- and post-beaver colonization. Using continuous stream discharge, stream temperature, synoptic tracer experiments, and groundwater elevation measurements, we documented pre-beaver conditions in the first year of the study. In the second year, we captured the initial effects of three beaver dams, while the third year included the effects of ten dams. After beaver colonization, reach-scale (~ 750 m in length) discharge observations showed a shift from slightly losing to gaining. However, at the smaller sub-reach scale (ranging from 56 to 185 m in length), the discharge gains and losses increased in variability due to more complex flow pathways with beaver dams forcing overland flow, increasing surface and subsurface storage, and increasing groundwater elevations. At the reach scale, temperatures were found to increase by 0.38 °C (3.8 %), which in part is explained by a 230 % increase in mean reach residence time. At the smallest, beaver dam scale (including upstream ponded area, beaver dam structure, and immediate downstream section), there were notable increases in the thermal heterogeneity where warmer and cooler niches were created. Through the quantification of hydrologic and thermal changes at different spatial and temporal scales, we document increased variability during post-beaver colonization and highlight the need to understand the impacts of beaver dams on stream ecosystems and their potential role in stream restoration.


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