Single-Species Spatial Dynamics May Contribute to Long-Term Rarity and Commonness

Ecology ◽  
1985 ◽  
Vol 66 (2) ◽  
pp. 335-343 ◽  
Author(s):  
Ilkka Hanski
Keyword(s):  
Spatial Dynamics ◽  
Single Species

scholarly journals Modeling cesium migration through Opalinus clay: a benchmark for single- and multi-species sorption-diffusion models

2021 ◽  
Author(s):  
Jesús F. Águila ◽  
Vanessa Montoya ◽  
Javier Samper ◽  
Luis Montenegro ◽  
Georg Kosakowski ◽  
...  
Keyword(s):  
Time Discretization ◽  
Single Species ◽  
Opalinus Clay ◽  
Sorption Behavior ◽  
Diffusion Experiment ◽  
Modeling Tools ◽  
Cesium Sorption ◽  
Code Performance ◽  
Good Agreement

AbstractSophisticated modeling of the migration of sorbing radionuclides in compacted claystones is needed for supporting the safety analysis of deep geological repositories for radioactive waste, which requires robust modeling tools/codes. Here, a benchmark related to a long term laboratory scale diffusion experiment of cesium, a moderately sorbing radionuclide, through Opalinus clay is presented. The benchmark was performed with the following codes: CORE2DV5, Flotran, COMSOL Multiphysics, OpenGeoSys-GEM, MCOTAC and PHREEQC v.3. The migration setup was solved with two different conceptual models, i) a single-species model by using a look-up table for a cesium sorption isotherm and ii) a multi-species diffusion model including a complex mechanistic cesium sorption model. The calculations were performed for three different cesium boundary concentrations (10−3, 10−5, 10−7 mol / L) to investigate the models/codes capabilities taking into account the nonlinear sorption behavior of cesium. Generally, good agreement for both single- and multi-species benchmark concepts could be achieved, however, some discrepancies have been identified, especially near the boundaries, where code specific spatial (and time) discretization had to be improved to achieve better agreement at the expense of longer computation times. In addition, the benchmark exercise yielded useful information on code performance, setup options, input and output data management, and post processing options. Finally, the comparison of single-species and multi-species model concepts showed that the single-species approach yielded generally earlier breakthrough, because this approach accounts neither for cation exchange of Cs+ with K+ and Na+, nor K+ and Na+ diffusion in the pore water.

scholarly journals Can we predict the future: juvenile finfish and their seagrass nurseries in the Chesapeake Bay

2013 ◽  
Vol 71 (3) ◽  
pp. 681-688 ◽  
Author(s):  
Cynthia M. Jones
Keyword(s):  
Climate Change ◽  
Chesapeake Bay ◽  
Juvenile Fish ◽  
Single Species ◽  
Potential Effect ◽  
Seagrass Habitat ◽  
Important Conclusion ◽  
The Relationship ◽  
Landscape Level

Abstract The importance of estuarine seagrass beds as nurseries for juvenile fish has become a universal paradigm, especially for estuaries that are as important as the Chesapeake Bay. Yet, scientific tests of this hypothesis were equivocal depending on species, location, and metrics. Moreover, seagrasses themselves are under threat and one-third of seagrasses have disappeared worldwide with 65% of their losses occurring in estuaries. Although there have been extensive studies of seagrasses in the Chesapeake Bay, surprisingly few studies have quantified the relationship between seagrass as nurseries for finfish in the Bay. Of the few studies that have directly evaluated the use of seagrass nurseries, most have concentrated on single species or were of short duration. Few landscape-level or long-term studies have examined this relationship in the Bay or explored the potential effect of climate change. This review paper summarizes the seagrass habitat value as nurseries and presents recent juvenile fish studies that address the dearth of research at the long term and landscape level with an emphasis on the Chesapeake Bay. An important conclusion upon the review of these studies is that predicting the effects of climate change on fishery production remains uncertain.

Spatial dynamics of a nonlocal delayed unstirred chemostat model with periodic input

2019 ◽  
Vol 12 (06) ◽  
pp. 1950065
Author(s):  
Wu-Jun Pu ◽  
Danhua Jiang ◽  
Ya Wang ◽  
Zhanbing Bai
Keyword(s):  
Existence And Uniqueness ◽  
Spatial Dynamics ◽  
Single Species ◽  
Uniqueness Of Solution ◽  
Uniform Persistence ◽  
Global Dynamics ◽  
Chemostat Model ◽  
Periodic Input

In this paper, a nonlocal delayed chemostat model of a single species feeding on a periodically varying input nutrient is proposed. By the theory of semigroup, the existence and uniqueness of solution of the system are obtained. Furthermore, we investigate a threshold result on the global dynamics, and the uniform persistence of the system is established.

Long-term spatial dynamics in vegetated seascapes: fragmentation and habitat loss in a human-impacted subtropical lagoon

2015 ◽  
Vol 37 (1) ◽  
pp. 200-214 ◽  
Author(s):  
Rolando O. Santos ◽  
Diego Lirman ◽  
Simon J. Pittman
Keyword(s):  
Habitat Loss ◽  
Spatial Dynamics ◽  
Subtropical Lagoon

Islands as refuges for threatened species: multispecies translocation and evidence of species interactions four decades on

2016 ◽  
Vol 38 (2) ◽  
pp. 204 ◽  
Author(s):  
Bertram Ostendorf ◽  
Wayne S. J. Boardman ◽  
David A. Taggart
Keyword(s):  
Threatened Species ◽  
Species Interactions ◽  
Ecosystem Engineer ◽  
Species Conservation ◽  
Single Species ◽  
Population Increase ◽  
Interspecies Interactions ◽  
Significant Preference ◽  
Extinction Rates

Australia has one of the worst mammal extinction rates in the world, with translocations to refuge locations increasingly being advocated to help address problems of species decline. Offshore islands can function as these refuges, removing species from threatening processes and providing a source of animals for reintroduction. Historically, the focus of many island translocations in Australia has been the conservation of a single species, with data on long-term translocation success and population dynamics after release generally lacking. Here we examine the results of a multispecies translocation onto Wedge Island, off the South Australian coast 30–40 years ago. Fewer than a dozen individuals of three species – southern hairy-nosed wombat (Lasiorhinus latifrons), black-footed rock-wallaby (Petrogale lateralis pearsonii), and brush-tailed bettong (Bettongia penicillata) – were released. All three species have shown substantial population increase and wombat activity across the island has increased exponentially with >700 burrows detected. Substantial levels of co-use of wombat burrows by rock-wallabies and bettongs were observed, providing clear evidence for interspecies interactions. Rock-wallabies showed a significant preference for wombat-active burrows (45% co-used), whereas bettongs showed a significant preference for wombat-inactive burrows (10% used). This study suggests that islands have significant potential for long-term threatened species conservation and that translocation of an ecosystem engineer may increase habitat complexity and help improve habitat suitability for multiple species and thus increase the overall conservation benefit.

Population dynamics of canopy trees in New Caledonian rain forests: are monodominant Nothofagus (Nothofagaceae) forests successional to mixed rain forests?

2013 ◽  
Vol 29 (6) ◽  
pp. 485-499 ◽  
Author(s):  
Jennifer Read ◽  
Tanguy Jaffré
Keyword(s):  
New Caledonia ◽  
Single Species ◽  
Secondary Forests ◽  
Rain Forests ◽  
Term Change ◽  
Shade Tolerant Species ◽  
Successional Stages ◽  
Continuous Regeneration ◽  
Canopy Species

Abstract:In New Caledonia, rain forests with an upper canopy dominated by single species of Nothofagus occur next to mixed-canopy forests, without discernible environmental cause. A potential explanation is that they are different successional stages. To test this hypothesis and predict long-term change in canopy dominance, population size structures of 61 canopy species were analysed in six Nothofagus-dominated forests and three adjacent mixed rain forests. Weibull analysis suggests that these Nothofagus forests are secondary forests, with recruitment insufficient to maintain monodominance, except at a high-altitude site. At low- to mid-altitudes the Nothofagus canopy is predicted to develop into a mixed canopy, unless moderate to severe disturbance occurs within its reproductive lifespan. However, adjacent mixed rain forests are also secondary, with 85% of analysed species showing no evidence of continuous regeneration. Fifteen species from both forest types showed reverse-J curves suggesting continuous regeneration, but only Calophyllum caledonicum did so consistently. Since few canopy species showed evidence of high shade tolerance and persistence, a small number of shade-tolerant species is predicted to dominate both forests in the long term, in the hypothetical absence of disturbance. Hence, temporal factors associated with disturbances play a key role in determining dominance in these forests.

Off flavours in large waterbodies: physics, chemistry and biology in synchrony

2007 ◽  
Vol 55 (5) ◽  
pp. 1-8 ◽  
Author(s):  
S.B. Watson ◽  
M. Charlton ◽  
Y.R. Rao ◽  
T. Howell ◽  
J. Ridal ◽  
...  
Keyword(s):  
Spatial Dynamics ◽  
Water Source ◽  
Past Century ◽  
Drinking Water Source ◽  
Physical Size ◽  
Spatial And Temporal Scales ◽  
Large Systems ◽  
Management Approaches ◽  
St Lawrence River

The Laurentian Great Lakes of North America are a drinking water source for millions of Canadian and US consumers. These waterbodies have undergone extensive change over the past century as a result of widespread degradation and remediation. Many of the Lakes are prone to taste and odour (T&O), and although these outbreaks have been poorly monitored, evidence suggests that they are increasing in frequency. Tracing and controlling T&O in such large systems presents a challenging task, due to their physical size and complexity. This paper presents an overview of recent investigative and management approaches to T&O in Lake Ontario and its outflow, the St. Lawrence River. We have identified three distinct patterns of T&O in these source-waters, caused by geosmin and 2-methylisoborneol and differing in their planktonic and benthic sources, and temporal and spatial dynamics. Each pattern has required a different approach by scientists and management, in partnership with the water industry. We have shown these T&O outbreaks are caused and moderated by physical, chemical and biological mechanisms over a spectrum of spatial and temporal scales. Canadian municipalities affected by these outbreaks have been key to the investigation of the links between T&O and ecosystem processes with the aim to develop more proactive water treatment and long-term management.

scholarly journals Integrating dispersal proxies in ecological and environmental research in the freshwater realm

2017 ◽  
Vol 25 (3) ◽  
pp. 334-349 ◽  
Author(s):  
Jani Heino ◽  
Janne Alahuhta ◽  
Terhi Ala-Hulkko ◽  
Harri Antikainen ◽  
Luis Mauricio Bini ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Restoration Ecology ◽  
Spatial Dynamics ◽  
Single Species ◽  
Environmental Research ◽  
Freshwater Systems ◽  
Biological Communities ◽  
Research Fields ◽  
Basic And Applied Research ◽  
Applied Fields

Dispersal is one of the key mechanisms affecting the distribution of individuals, populations, and communities in nature. Despite advances in the study of single species, it has been notoriously difficult to account for dispersal in multispecies metacommunities, where it potentially has strong effects on community structure beyond those of local environmental conditions. Dispersal should thus be directly integrated in both basic and applied research by using proxies. Here, we review the use of proxies in the current metacommunity research, suggest new proxies, and discuss how proxies could be used in community modelling, particularly in freshwater systems. We suggest that while traditional proxies may still be useful, proxies formerly utilized in transport geography may provide useful novel insights into the structuring of biological communities in freshwater systems. We also suggest that understanding the utility of such proxies for dispersal in metacommunities is highly important for many applied fields such as freshwater bioassessment, conservation planning, and recolonization research in the context of restoration ecology. These research fields have often ignored spatial dynamics and focused mostly on local environmental conditions and changes therein. Yet, the conclusions of these applied studies may change considerably if dispersal is taken into account.

scholarly journals The order Tethyida (Porifera) in California: taxonomy, systematics, and the first member of the family Hemiasterellidae in the Eastern Pacific

2020 ◽  
Author(s):  
Thomas L. Turner
Keyword(s):  
Kelp Forest ◽  
Single Species ◽  
Ecological Monitoring ◽  
Eastern Pacific ◽  
The Third ◽  
Morphological Taxonomy ◽  
The Family ◽  
Ecological Importance

AbstractSponges (phylum Porifera) are ubiquitous inhabitants of marine ecosystems and have been shown to provide substantial ecosystem services. Despite this ecological importance, the sponge fauna in California has received little study. Here I use a collection of kelp forest sponges to describe the diversity of the order Tethyida in California. This order contains the genus Tethya, which has been included in long-term ecological monitoring projects. I show that Tethya vacua is a junior synonym of Tethya californiana, and thus all Tethya populations known in California belong to a single species. Genetic data from California’s only Timeidae, Timea authia, indicate that this species is in fact in the Tethyidae and is the third known member of the genus Tethytimea. I also describe the first member of the family Hemiasterellidae from the Eastern Pacific, Galaxia gaviotensis gen. nov. sp. nov. By combining field photographs, morphological taxonomy, and phylogenetic analysis of these samples, this work will facilitate future efforts to understand the evolution of this order and the ecological role of sponges in the California kelp forest.

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