Hydrologic dynamics and ecosystem structure

2003 ◽  
Vol 47 (6) ◽  
pp. 17-24 ◽  
Author(s):  
I. Rodríguez-Iturbe
Keyword(s):  
Hydrological Cycle ◽  
Limiting Factor ◽  
Ecosystem Structure ◽  
Nutrient Cycles ◽  
Stochastic Fluctuation ◽  
Ecological Patterns ◽  
Probabilistic Structure ◽  
Patterns And Processes ◽  
Hydrologic Inputs ◽  
Soil Climate

Ecohydrology is the science that studies the mutual interaction between the hydrological cycle and ecosystems. Such an interaction is especially intense in water-controlled ecosystems, where water may be a limiting factor, not only because of its scarcity, but also because of its intermittent and unpredictable appearance. Hydrologic dynamics is shown to be a crucial factor for ecological patterns and processes. The probabilistic structure of soil moisture in time and space is presented as the key linkage between soil, climate and vegetation dynamics. Nutrient cycles, vegetation coexistence and plant response to environmental conditions are all intimately linked to the stochastic fluctuation of the hydrologic inputs driving an ecosystem.

scholarly journals Stable Isotope Composition of River Waters across the World

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1760 ◽  
Author(s):  
Yi Nan ◽  
Fuqiang Tian ◽  
Hongchang Hu ◽  
Lixin Wang ◽  
Sihan Zhao
Keyword(s):  
Multiple Regression ◽  
Hydrological Cycle ◽  
Isotope Composition ◽  
Meta Analysis ◽  
Global Network ◽  
River Waters ◽  
Spatial Coverage ◽  
Ecological Patterns ◽  
Data Points ◽  
Patterns And Processes

Stable isotopes of O and H in water are meaningful indicators of hydrological and ecological patterns and processes. The Global Network of Isotopes in Precipitation (GNIP) and the Global Network of Isotopes in Rivers (GNIR) are the two most important global databases of isotopes in precipitation and rivers. While the data of GNIP is almost globally distributed, GNIR has an incomplete spatial coverage, which hinders the utilization of river isotopes to study global hydrological cycle. To fill this knowledge gap, this study supplements GNIR and provides a river isotope database with global-coverage by the meta-analysis method, i.e., collecting 17015 additional data points from 215 published articles. Based on the newly compiled database, we find that (1) the relationship between δ18O and δ2H in river waters exhibits an asymmetric imbricate feature, and bifurcation can be observed in Africa and North America, indicating the effect of evaporation on isotopes; (2) multiple regression analysis with geographical factors indicates that spatial patterns of river isotopes are quite different across regions; (3) multiple regression with geographical and meteorological factors can well predict the river isotopes, which provides regional regression models with r2 of 0.50 to 0.89, and the best predictors in different regions are different. This work presents a global map of river isotopes and establishes a benchmark for further research on isotopes in rivers.

scholarly journals Fragmented Landscape, Fragmented Knowledge: A Synthesis of Renosterveld Ecology and Conservation

2019 ◽  
Vol 46 (2) ◽  
pp. 171-179 ◽  
Author(s):  
Emmeline N Topp ◽  
Jacqueline Loos
Keyword(s):  
Cape Floristic Region ◽  
Fragmented Landscape ◽  
Biodiversity Hotspots ◽  
Current State ◽  
Ecological Patterns ◽  
Local Patch ◽  
Populated Region ◽  
Patterns And Processes ◽  
First Time ◽  
Effective Conservation

SummaryKnowledge of ecological patterns and processes is key to effective conservation of biodiversity hotspots under threat. Renosterveld is one of the most critically endangered habitats in the biologically unique Cape Floristic Region, South Africa. For the first time, we map and synthesize the current state of knowledge on renosterveld ecology and conservation. We investigated 132 studies for the themes, locations and taxa of renosterveld research and the fragmentation, threats, recommendations and barriers to renosterveld conservation. More studies focused on plants than any other taxa (48% of articles) and are conducted mostly in larger, intact renosterveld fragments. The most commonly identified threat to renosterveld was agricultural intensification; conservation recommendations spanned improved farming practices, formal protection and local patch management. Conservation implementation has been piecemeal and has depended largely on the goodwill of landowners, which can be constrained by costs of conservation measures and a lack of suitable restoration means. Citizen science is a promising potential solution to some barriers. Fragmented knowledge in such a transformed and relatively densely populated region highlights the scale of knowledge gaps for other biodiversity hotspots and has implications for ongoing conservation work.

scholarly journals Using trophic flows and ecosystem structure to model the effects of fishing in the Jurien Bay Marine Park, temperate Western Australia

2011 ◽  
Vol 62 (5) ◽  
pp. 421 ◽  
Author(s):  
Hector M. Lozano-Montes ◽  
Neil R. Loneragan ◽  
Russell C. Babcock ◽  
Kelsie Jackson
Keyword(s):  
Western Australia ◽  
Negative Impact ◽  
Limiting Factor ◽  
Commercial Fishing ◽  
Ecosystem Structure ◽  
Fishing Mortality ◽  
Benthic Primary Production ◽  
Cascading Effects ◽  
Marine Park ◽  
The Impact

Understanding the impacts of fishing on the trophic structure of systems has become increasingly important because of the introduction of Ecosystem Based Fisheries Management and the legislative requirements of fisheries to demonstrate that they are not having a negative impact on other species. A biomass-based dynamic model of Jurien Bay Marine Park (∼30°S) was constructed using Ecopath to investigate the ecosystem impacts of fishing (mainly commercial rock lobster, Panulirus cygnus) in the park, as an example of the potential responses of temperate marine ecosystems in Western Australia to commercial fishing. A simulated 50% reduction in fishing mortality for commercial finfish predicted that after 20 years, the biomass of important fished species (i.e. Pagrus auratus and Choerodon rubescens) would increase by up to 30%. A simulated total fishing closure resulted in much larger (2.5–8 fold) increases in targeted populations, but did not result in any predicted cascading effects on grazing invertebrates and benthic primary producers. The simulations suggest that the structure of this ecosystem is characterised more by bottom-up than top-down processes; i.e. benthic primary production is a major limiting factor. The present study identified trophic linkages and ecosystem processes such as the role of both low and high trophic-level groups and the impact of fishing mortality in the marine park, an essential step towards distinguishing the impacts of fishing from those attributable to natural or other human-induced changes.

Landscape allometry: from tidal channel hydraulic geometry to benthic ecology

2002 ◽  
Vol 59 (8) ◽  
pp. 1418-1427 ◽  
Author(s):  
W Gregory Hood
Keyword(s):  
Exit Time ◽  
Surface Velocity ◽  
Hydraulic Geometry ◽  
Tidal Channel ◽  
Tidal Channels ◽  
Surface Deposit ◽  
Channel Size ◽  
Channel Form ◽  
Ecological Patterns ◽  
Patterns And Processes

The use of hydraulic geometry and other geomorphic indices has been recommended for habitat restoration and creation of estuarine tidal channels. Although such an approach provides design guidance for tidal channel form, it does not provide guidance for the ecological consequences of channel form. This study investigates the potential linkage of the scaling of tidal channel form with ecological patterns and processes in estuarine tidal channels of the lower Chehalis River, Washington, U.S.A. Ebb tide surface velocity was related to channel size, as was exit time and export probability of tiny drogues, which mimic floating allochthonous detritus. Consequently, the amount of organic material in channel sediments scaled negatively with channel size as did the abundance of benthic surface deposit feeders. These observations suggest that the highest concentrations of fish feeding in estuarine tidal channels may be in smaller channels or in the smaller and more distal portions of large channels. Scaling of ecological patterns and processes with tidal channel size may be an example of a more general ecological scaling with landscape form, i.e., landscape allometry.

scholarly journals Water quality in two Australian dryland rivers: spatial and temporal variability and the role of flow

2010 ◽  
Vol 61 (8) ◽  
pp. 864 ◽  
Author(s):  
Fran Sheldon ◽  
Christine S. Fellows
Keyword(s):  
Water Quality ◽  
Temporal Variability ◽  
Temporal Dynamics ◽  
Spatial And Temporal Variability ◽  
Quality Guidelines ◽  
Spatial And Temporal Dynamics ◽  
Flow Phase ◽  
Ecological Patterns ◽  
Patterns And Processes ◽  
Dryland Rivers

Water quality, along with hydrology, plays an important role in the spatial and temporal dynamics of a range of ecological patterns and processes in large rivers and is also often a key component of river health assessments. Geology and land use are significant drivers of water quality during flow periods while during periods of no-flow, local-scale factors such as evaporation, groundwater influence and the concentration and precipitation of compounds are important. This study explored the water quality changes in two Australian dryland rivers, the Cooper Creek (Lake Eyre Basin) and the Warrego River (Murray–Darling Basin), across different hydrological phases over several years. Water quality varied both spatially and temporally; the greatest spatial variability occurred during the no-flow phase, with temporal changes driven by flow. Concentrations of major anions and cations also varied spatially and temporally, with an overall cation dominance of calcium and magnesium and an anion dominance of bicarbonate. This bicarbonate dominance contrasts with previous data from inland lentic systems where sodium chloride was found to dominate. Such extreme spatial and temporal variability hampers successful derivation of water quality guidelines for these variable rivers and suggests such guidelines would need to be developed with respect to ‘flow phase’.

scholarly journals Macrosystems ecology: understanding ecological patterns and processes at continental scales

2014 ◽  
Vol 12 (1) ◽  
pp. 5-14 ◽  
Author(s):  
James B Heffernan ◽  
Patricia A Soranno ◽  
Michael J Angilletta ◽  
Lauren B Buckley ◽  
Daniel S Gruner ◽  
...  
Keyword(s):  
Ecological Patterns ◽  
Macrosystems Ecology ◽  
Patterns And Processes

scholarly journals SKENARIO MASA TANAM KAPAS UNTUK MENEKAN RISIKO KEKERINGAN : STUDI KASUS KABUPATEN JENEPONTO PROVINSI SULAWESI SELATAN(COTTON PLANTING PERIOD SCENARIO FOR MINIMIZING DROUGHT RISK : CASE STUDY JENEPONTO DISTRICT, SOUTH SULAWESI PROVINCE …

Agromet ◽  
2007 ◽  
Vol 21 (1) ◽  
pp. 21
Author(s):  
P. Redjekiningrum ◽  
Y. Apriyana ◽  
K.S. Haryanti
Keyword(s):  
Water Resources ◽  
Plant Production ◽  
Limiting Factor ◽  
Drought Risk ◽  
Satisfaction Index ◽  
South Sulawesi ◽  
Supplementary Irrigation ◽  
Soil Climate ◽  
Research Show

<p>Water stress is a very important limiting factor for cotton cultivation in Jeneponto District, South Sulawesi Provine. Therefore, it is necessary to optimize water resources. One alternative is to obtain potency of water resources using soil-climate-crop simulation model to calculate ETR/ETM ratio (water satisfaction index). ETR/ETM ratio describing efficiency of water used by the plant. Based on the ratio, scenario of proper planting period can be predicted to minimize drought risk. Based on this idea, an experiment was conducted to mapping of planting periods and water used to enhance the expansion of cotton plantation. The results of research show that potential planting period for Bangkala and West Bangkala districts start from the 3rd dekad of September until the 1st dekad of January, while the best period is on the 1st dekad of November. Potential of planting period for Bontoramba and Turatea districts starts from the 3rd dekad of September until the 1st dekad of May, while the best period is on the 3rd dekad of November. In addition, the appropriate planting period for Batang, Kelara, and Rumbia districts start from the 3rd dekad of September until the 3rd dekad of April, while the best period is on the 1st dekad of December. Requirement for supplementary irrigation for 140 days after planting is about 180-304 mm. However, common necessity of cotton supplementary irrigation for 1-35 day is about 25 – 51 mm, while that is during flowering and fruiting (35 -60 day after planting), ripening (60-105 day after planting), and ripening (105-140 day after planting), are about 40-62, 115-135, 0-68 mm, respectively. It is concluded, deficit and surplus of water for less than 60 dap is not significantly influence plant production, but that is for 60 – 105 day after planting significantly reduces yield of the plant.</p>

scholarly journals A simulation study of the use of temporal occupancy for identifying core and transient species

2020 ◽  
Author(s):  
Sara Snell Taylor ◽  
Jessica R. Coyle ◽  
Ethan P. White ◽  
Allen H. Hurlbert
Keyword(s):  
Transient Species ◽  
Imperfect Detection ◽  
Heterogeneous Landscapes ◽  
Core Species ◽  
Simulation Based ◽  
Ecological Patterns ◽  
Misclassification Rates ◽  
Patterns And Processes ◽  
Source Sink

AbstractTransient species, which do not maintain self-sustaining populations in a system where they are observed, are ubiquitous in nature and their presence often impacts the interpretation of ecological patterns and processes. Identifying transient species from temporal occupancy, the proportion of time a species is observed at a given site over a time series, is subject to classification errors as a result of imperfect detection and source-sink dynamics. We use a simulation-based approach to assess how often errors in detection or classification occur in order to validate the use of temporal occupancy as a metric for inferring whether a species is a core or transient member of a community. We found that low detection increases error in the classification of core species, while high habitat heterogeneity and high detection increase error in classification of transient species. These findings confirm that temporal occupancy is a valid metric for inferring whether a species can maintain a self-sustaining population, but imperfect detection, low abundance, and highly heterogeneous landscapes may yield high misclassification rates.

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