scholarly journals Network-level containment of single-species bioengineering

2021 ◽  
Author(s):  
Victor Maull ◽  
Ricard Sole
Keyword(s):  
Single Species ◽  
Ecological Systems ◽  
Dynamic Responses ◽  
Interaction Matrix ◽  
Anthropogenic Effects ◽  
Kelp Forests ◽  
Tipping Points ◽  
Resident Species ◽  
Catastrophic Shifts ◽  
High Diversity

Ecological systems are facing major diversity losses in this century due to Anthropogenic effects. Habitat loss, overexploitation of resources, invasion and pollution are rapidly jeopardising the survival of whole communities, as revealed by pronounced population losses. Moreover, the potential of future tipping points further complicate their survival and change our perspective of risk. It has been recently suggested that a potential approach to flatten the curve of species extinction and prevent catastrophic shifts would involve the engineering of one selected species within one of these communities, aiming at helping the maintenance of key conditions compatible with high diversity. Such possibility has started to become part of potential intervention scenarios to preserve coral reefs, kelp forests or soil microbiomes in drylands. Despite its potential, very little is known about the actual dynamic responses of complex ecological networks to the introduction of a synthetic strains derived from a resident species. In this paper we address this problem by modelling the response of a competitive community to the addition of a synthetic strain derived from a member of a stable ecosystem. We show that the community interaction matrix largely limits the spread of the engineered strain, thus suggesting that species diversity acts as an ecological firewall. Implications for future restoration and terraformation strategies are discussed.

scholarly journals Predicting Collapse of Complex Ecological Systems: Quantifying the Stability-Complexity Continuum

2019 ◽  
Author(s):  
Susanne Pettersson ◽  
Van M. Savage ◽  
Martin Nilsson Jacobi
Keyword(s):  
Single Species ◽  
Ecological Systems ◽  
Ecological Research ◽  
Stability Criteria ◽  
Numerical Techniques ◽  
Intermediate Regime ◽  
Limits Of Stability ◽  
Species Abundances ◽  
The Stability ◽  
Degree Of Instability

Dynamical shifts between the extremes of stability and collapse are hallmarks of ecological systems. These shifts are limited by and change with biodiversity, complexity, and the topology and hierarchy of interactions. Most ecological research has focused on identifying conditions for a system to shift from stability to any degree of instability—species abundances do not return to exact same values after perturbation. Real ecosystems likely have a continuum of shifting between stability and collapse that depends on the specifics of how the interactions are structured, as well as the type and degree of disturbance due to environmental change. Here we map boundaries for the extremes of strict stability and collapse. In between these boundaries, we find an intermediate regime that consists of single-species extinctions, which we call the Extinction Continuum. We also develop a metric that locates the position of the system within the Extinction Continuum—thus quantifying proximity to stability or collapse—in terms of ecologically measurable quantities such as growth rates and interaction strengths. Furthermore, we provide analytical and numerical techniques for estimating our new metric. We show that our metric does an excellent job of capturing the system behaviour in comparison with other existing methods—such as May’s stability criteria or critical slowdown. Our metric should thus enable deeper insights about how to classify real systems in terms of their overall dynamics and their limits of stability and collapse.

High diversity of Cladocera (Crustacea: Branchiopoda) in a Ramsar site Lake Kud-Thing, Northeast Thailand

Zootaxa ◽  
2020 ◽  
Vol 4780 (2) ◽  
pp. 275-290
Author(s):  
SUPATRA TIANG-NGA ◽  
ARTEM Y. SINEV ◽  
LA-ORSRI SANOAMUANG
Keyword(s):  
New Records ◽  
Single Species ◽  
Biodiversity Hotspots ◽  
Ramsar Site ◽  
Northeast Thailand ◽  
Intensive Study ◽  
Natural Lakes ◽  
Ceriodaphnia Cornuta ◽  
High Diversity ◽  
Planktonic Species

An intensive study of cladoceran diversity in Lake Kud-Thing, a Ramsar site of Bueng Kan Province, Thailand, was conducted. One hundred and twenty-five qualitative samples were collected from 15 localities during the period from June 2012 to November 2014. A total of 58 species belonging to 38 genera was recorded. Three species, Chydorus idrisi Sinev 2014, Karualona kwangsiensis (Chiang 1963) and Streblocerus cf. serricaudatus (Fisher 1849) are new records for Thailand. The most species rich family was Chydoridae (32 species, 55% of the encountered species in the lake) followed by Sididae (8 species, 14%) and Macrothricidae (8 species, 14%) while only a single species of Ilyocryptidae was observed. The most frequently encountered planktonic species were Ceriodaphnia cornuta Sars 1885, Bosmina cf. meridionalis Sars 1904 and Ephemeroporus barroisi (Richard 1894). A newly described chydorid, Anthalona spinifera Tiang-nga, Sinev & Sanoamuang 2016, was also recorded from this lake. The number of cladocerans recorded in this study is remarkably higher than that of previous studies in other natural lakes (17–40 species) within Thailand. In addition to earlier records, the number of cladocerans of Lake Kud-Thing has been updated to 62 species, about two times higher than that of other lakes in this region. Thus, our results suggest that Lake Kud-Thing is one of the biodiversity hotspots for Cladocera of Southeast Asia. 

scholarly journals Predicting collapse of complex ecological systems: quantifying the stability–complexity continuum

2020 ◽  
Vol 17 (166) ◽  
pp. 20190391 ◽  
Author(s):  
Susanne Pettersson ◽  
Van M. Savage ◽  
Martin Nilsson Jacobi
Keyword(s):  
Single Species ◽  
Ecological Systems ◽  
Ecological Research ◽  
Stability Criteria ◽  
Numerical Techniques ◽  
Intermediate Regime ◽  
Limits Of Stability ◽  
Species Abundances ◽  
The Stability ◽  
Degree Of Instability

Dynamical shifts between the extremes of stability and collapse are hallmarks of ecological systems. These shifts are limited by and change with biodiversity, complexity, and the topology and hierarchy of interactions. Most ecological research has focused on identifying conditions for a system to shift from stability to any degree of instability—species abundances do not return to exact same values after perturbation. Real ecosystems likely have a continuum of shifting between stability and collapse that depends on the specifics of how the interactions are structured, as well as the type and degree of disturbance due to environmental change. Here we map boundaries for the extremes of strict stability and collapse. In between these boundaries, we find an intermediate regime that consists of single-species extinctions, which we call the extinction continuum. We also develop a metric that locates the position of the system within the extinction continuum—thus quantifying proximity to stability or collapse—in terms of ecologically measurable quantities such as growth rates and interaction strengths. Furthermore, we provide analytical and numerical techniques for estimating our new metric. We show that our metric does an excellent job of capturing the system's behaviour in comparison with other existing methods—such as May’s stability criteria or critical slowdown. Our metric should thus enable deeper insights about how to classify real systems in terms of their overall dynamics and their limits of stability and collapse.

A monograph of the Bradoriid arthropods from the Lower Cambrian of SW China

2001 ◽  
Vol 92 (3) ◽  
pp. 347-409 ◽  
Author(s):  
Hou Xian-guang ◽  
David J. Siveter ◽  
Mark Williams ◽  
Feng Xiang-hong
Keyword(s):  
Lower Cambrian ◽  
Yunnan Province ◽  
Single Species ◽  
Taxonomic Diversity ◽  
Zoological Nomenclature ◽  
Yangtze Platform ◽  
Animal Group ◽  
Sw China ◽  
Almost All ◽  
High Diversity

ABSTRACTThis paper evaluates the taxonomy, biostratigraphy, and palaeogeographical significance of the Cambrian bradoriid arthropods of China, the majority of which occur in the lower Cambrian of SW China. Of bradoriid faunas world-wide, Chinese occurrences yield the greatest number of specimens and a comparatively high diversity at all taxonomic levels. Nevertheless, taxonomic diversity is much less than previously supposed. Some 80 bradoriid genera and nearly 300 species have been proposed on the basis of Chinese material. By contrast, in our study, which encompasses all of the important Chinese bradoriid faunas, we recognise only 16 genera and 21 species, including those treated under open nomenclature. Interpretation of deformed specimens as discrete species and lack of application of the rules of the International Code of Zoological Nomenclature resulted in taxonomic splitting and a proliferation of names. There are an additional 12 poorly known monotypic genera of uncertain systematic status that are listed but not treated further herein. One phosphatocopid species, a group originally thought closely related to the Bradoriida, is also described.Most Chinese bradoriid material is known from Yunnan Province; the group also occurs in Guizhou, Henan, Hubei, Hunan, Liaoning, Qinghai, Shaanxi, Sichuan, Xinjiang and Zhejiang provinces. The first bradoriids occur just below the Abadiella trilobite Biozone. They are most prolific and diverse in the Qiongzhusian Stage, constituting the most abundant animal group; the succeeding Canglangpuian Stage contains fewer individuals and species. A previously proposed bradoriid biozonal scheme lacks rigour and is of little practical value: of the five supposed biozones, two correspond to trilobite zones and three are based on taxa that herein are considered to belong to a single species.Palaeogeographically the bradoriids occur in the Middle and especially the Western subprovinces of the Cambrian of the SW China (Yangtze) Platform. Almost all of the bradoriid genera and species are endemic to that region. The palaeogeographical links with other bradoriid faunas are mostly within the Redlichiid trilobite Realm, with areas such as N China, Australia and parts of central Asia.

scholarly journals Treadmills of Production and Destruction in the Anthropocene

2020 ◽  
Vol 26 (2) ◽  
pp. 231-262
Author(s):  
Chad L. Smith ◽  
Gregory Hooks ◽  
Michael Lengefeld
Keyword(s):  
Environmental Economic ◽  
Latin American ◽  
Human Activities ◽  
Ecological Systems ◽  
Social Consequences ◽  
Tipping Points ◽  
Critical Realist ◽  
The Andes ◽  
Latin American Countries ◽  
Realist Perspective

Human activities in Latin American countries have resulted in past and ongoing deforestation located in the Amazon and the Andes.  Demonstrative of this new Anthropocene Epoch, the illegal production of cocaine stands as a major driver of these environmental outcomes in these countries; however, in recent years the extraction of illegal gold has yielded larger export values than that of cocaine.  The consequences of these practices have far-reaching environmental, economic, and social consequences.  Using a critical realist perspective, we investigate and analyze how, when, and under what conditions the treadmills of production and destruction are absent, present, and thriving in Colombia and Peru.  The implications of these relationships are grave as both the Amazon and the Andes are undergoing extensive transformations – damage that represents the Anthropocene Epoch in which human activities are driving ecological systems toward “tipping points”.  We find that the two treadmills operate differently within each country and that treadmills are not ubiquitous but are, instead, contingent.  We underscore the fact that when present, both types of treadmills have the ability to engage in social and environmental destructions, sometimes violently so.

scholarly journals Diversity of resident plant communities could weaken their allelopathic resistance against alien and native invaders

2021 ◽  
Author(s):  
Ling Yuan ◽  
Junmin Li ◽  
Mark van Kleunen
Keyword(s):  
Plant Communities ◽  
Single Species ◽  
Resident Species ◽  
Test Species ◽  
Diverse Communities ◽  
Allelopathic Effects ◽  
Almost All ◽  
Germination Experiment ◽  
Germinated Seeds

AbstractElton’s classic diversity-invasibility hypothesis posits that diversity of resident communities increases resistance against invaders. We tested whether the diversity-invasibility relationsip might be mediated by allelopathic effects of the resident species. In a large germination experiment, we exposed seeds of six alien and six native test species to leachates of one, three, six or twelve species. The leachates tended to slightly delay germination, and almost all single-species leachates reduced the proportion of germinated seeds. Nevertheless, the overall effect of the plant leachate mixtures on the proportion of germinated seeds was not significant. This was because a higher diversity of the leachates increased the proportion of germinated seeds, particularly for native test species. Among the six alien test species, it was only the most invasive one that benefited from increased diversity of the leachates, just like the natives did. Overall, our findings suggest that allelopathy of diverse communities does not provide resistance but could actually facilitate the germination of invaders.

scholarly journals Social-Ecological Systems Insights for Navigating the Dynamics of the Anthropocene

2018 ◽  
Vol 43 (1) ◽  
pp. 267-289 ◽  
Author(s):  
Belinda Reyers ◽  
Carl Folke ◽  
Michele-Lee Moore ◽  
Reinette Biggs ◽  
Victor Galaz
Keyword(s):  
Sustainable Development ◽  
Transformational Change ◽  
Ecological Systems ◽  
Tipping Points ◽  
Social Ecological Systems ◽  
Social Ecological ◽  
Ecological Aspects ◽  
Values And Beliefs ◽  
Development Practice

Social-ecological systems (SES) research offers new theory and evidence to transform sustainable development to better contend with the challenges of the Anthropocene. Four insights from contemporary SES literature on ( a) intertwined SES, ( b) cross-scale dynamics, ( c) systemic tipping points, and ( d) transformational change are explored. Based on these insights, shifts in sustainable development practice are suggested to recognize and govern the complex and codeveloping social and ecological aspects of development challenges. The potential susceptibility of SES to nonlinear systemic reconfigurations is highlighted, as well as the opportunities, agency, and capacities required to foster reconfigurative transformations for sustainable development. SES research proposes the need for diverse values and beliefs that are more in tune with the deep, dynamic connections between social and ecological systems to transform development practice and to support capacities to deal with shocks and surprises. From these perspectives, SES research offers new outlooks, practices, and novel opportunity spaces from which to address the challenges of the Anthropocene.

scholarly journals Kelp Forests: Catastrophes, Resilience, and Management

2021 ◽  
Vol 9 ◽  
Author(s):  
Elizabeth A. Wilman
Keyword(s):  
Adaptive Management ◽  
Natural Capital ◽  
Abiotic Factors ◽  
Marine Ecosystem ◽  
Kelp Forest ◽  
Kelp Forests ◽  
Haida Gwaii ◽  
Management Controls ◽  
And Control ◽  
Catastrophic Shifts

Resilient kelp forests provide foundation habitat for marine ecosystems and are indicators of the ecosystems’ sustainable natural capital. Loss of resilience and imperfectly reversible catastrophic shifts from kelp forests to urchin barrens, due to pollution or loss of a top predator, are part of an ecological tipping point phenomenon, and involve a loss in sustainable natural capital. Management controls to prevent or reverse these shifts and losses are classified in a number of ways. Systemic controls eliminate the cause of the problem. Symptomatic controls use leverage points for more direct control of the populations affected, urchin harvesting or culling, or kelp enhancement. There is a distinction between ongoing structural (press) controls versus temporary or intermittent perturbation (pulse) controls, and one between shift preventing versus shift reversing or restorative controls. Adaptive management and the options it creates both focus on reductions in uncertainty and control policies with the flexibility to take advantage of those reductions. The various management distinctions are most easily understood by modeling the predator-urchin-kelp marine ecosystem. This paper develops a mathematical model of the ecosystem that has the potential for two different catastrophic shifts between equilibria. Pulse disturbances, originating from exogenous abiotic factors or population dynamics elsewhere in the metacommunity, can activate shifts. A measure of probabilistic resilience is developed and used as part of an assessment of the ecosystem’s sustainable stock of natural capital. With perturbation outcomes clustered around the originating equilibrium, hysteresis is activated, resulting imperfect reversibility of catastrophic shifts, and a loss in natural capital. The difficulty of reversing a shift from kelp forest to urchin barren, with an associated loss in sustainable natural capital, is an example. Management controls are modeled. I find that systemic and symptomatic, and press and pulse, controls can be complementary. Restorative controls tend to be more difficult or costly than preventative ones. Adaptive management, favoring flexible, often preventative, controls, creates option value, lowering control costs and/or losses in sustainable natural capital. Two cases are used to illustrate, Tasmania, Australia and Haida Gwaii, Canada.

scholarly journals Complexity-stability relationship in empirical microbial ecosystems

2021 ◽  
Author(s):  
Yogev Yonatan ◽  
Guy Amit ◽  
Amir Bashan ◽  
Yonatan Friedman
Keyword(s):  
Microbial Communities ◽  
A Priori ◽  
Interaction Network ◽  
Ecological Systems ◽  
Resident Species ◽  
Computational Framework ◽  
Microbial Ecosystems ◽  
The Rich ◽  
Central Paradigm ◽  
Geographical Locations

May's stability theory, which holds that large ecosystems can be stable up to a critical level of complexity, a product of the number of resident species and the intensity of their interactions, has been a central paradigm in theoretical ecology. So far, however, empirically demonstrating this theory in real ecological systems has been a long-standing challenge, with inconsistent results. Especially, it is unknown whether this theory is pertinent in the rich and complex communities of natural microbiomes, mainly due to the challenge of reliably reconstructing such large ecological interaction networks. Here, we introduce a novel computational framework for estimating an ecosystem's complexity without relying on a priori knowledge of its underlying interaction network. By applying this method to human-associated microbial communities from different body sites and sponge-associated microbial communities from different geographical locations, we found that in both cases the communities display a pronounced trade-off between the number of species and their effective connectance. These results suggest that natural microbiomes are shaped by stability constraints, which limit their complexity.

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