scholarly journals Rarity of a top predator triggers continent-wide collapse of mammal prey: dingoes and marsupials in Australia

2006 ◽  
Vol 274 (1608) ◽  
pp. 341-346 ◽  
Author(s):  
Christopher N Johnson ◽  
Joanne L Isaac ◽  
Diana O Fisher
Keyword(s):  
Red Fox ◽  
Critical Factor ◽  
Terrestrial Ecosystems ◽  
Small Scale ◽  
Top Predator ◽  
Feral Cat ◽  
European Settlement ◽  
Top Predators ◽  
Strong Positive Relationship

Top predators in terrestrial ecosystems may limit populations of smaller predators that could otherwise become over abundant and cause declines and extinctions of some prey. It is therefore possible that top predators indirectly protect many species of prey from excessive predation. This effect has been demonstrated in some small-scale studies, but it is not known how general or important it is in maintaining prey biodiversity. During the last 150 years, Australia has suffered the world's highest rate of mammal decline and extinction, and most evidence points to introduced mid-sized predators (the red fox and the feral cat) as the cause. Here, we test the idea that the decline of Australia's largest native predator, the dingo, played a role in these extinctions. Dingoes were persecuted from the beginning of European settlement in Australia and have been eliminated or made rare over large parts of the continent. We show a strong positive relationship between the survival of marsupials and the geographical overlap with high-density dingo populations. Our results suggest that the rarity of dingoes was a critical factor which allowed smaller predators to overwhelm marsupial prey, triggering extinction over much of the continent. This is evidence of a crucial role of top predators in maintaining prey biodiversity at large scales in terrestrial ecosystems and suggests that many remaining Australian mammals would benefit from the positive management of dingoes.

Role of Terrestrial Ecosystems Planted with Ligneous Species in M.H.E.A. System Receiving Urban Wastewaters

1999 ◽  
Vol 40 (3) ◽  
pp. 187-194
Author(s):  
M. Nemcova ◽  
D. Cadelli ◽  
M. Radoux
Keyword(s):  
Phosphorus Removal ◽  
Aquatic Ecosystems ◽  
Terrestrial Ecosystems ◽  
Stage Ii ◽  
Small Scale ◽  
Experimental Plant ◽  
Tertiary Treatment ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal

Tests were carried out in a small-scale experimental plant. The system consisted of aquatic ecosystems without macrophytes (stage I) followed by semi-aquatic ecosystems planted with Typha latifolia L. (stage II). The outflow of stage II was evenly distributed into 10 units of terrestrial ecosystems (stage III), planted with ligneous species or without vegetation (control). The whole plant received a hydraulic load of 384 1/day of urban wastewaters. The net treatment area per person equivalent (PE) was 8 m2. The study focused on the evaluation of the role of terrestrial ecosystems mainly in tertiary treatment (nitrogen and phosphorus removal). Stages I and II with a surface area of 4 m2/PE assure a primary and secondary purification level that conforms with European standards. As for the tertiary treatment, removal efficiency remains inadequate. The primary and secondary efficiencies were considerably enhanced by installing terrestrial ecosystems after the two previous stages. The outflow water of all tested successions respects the European norms for suspended solids (35 mg/l), COD (125 mg/l) and BOD5 (25 mg/l). Concerning tertiary efficiency, the planted ecosystems systematically enhance nitrogen and phosphorus removal compared to the control sand. The succession with Salix has shown the best results. The outflow concentrations were 0.8 and 3.7 mg/l of total nitrogen and 1.8 and 1.3 mg/l of total phosphorus respectively (average values for periods 1995 and 1996). The control successions containing non-planted unit (sand) were significantly the least efficient for both nitrogen and phosphorus removal.

The interplay between fishery yield and top predator culling in a multispecies fishery context

2020 ◽  
Vol 37 (3) ◽  
pp. 351-363
Author(s):  
Michel Iskin da S Costa ◽  
Lucas Dos Anjos
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Fisheries Management ◽  
Fishery Management ◽  
Target Species ◽  
Top Predator ◽  
Predator Removal ◽  
Top Predators ◽  
Theoretical Population

Abstract In food webs, fishery can play the role of top predator, competing thus with other top predators for valuable food resources. In this view, it has been claimed in fisheries management that culling of top predators can be a means to improve fishery yield. To investigate this hypothesis, we use theoretical population models to assess in a multispecies context how fishery yield from target species harvest responds to top predator cull. Defying crisp summary, the four analysed food web models show that this response may be either positive or negative or both, indicating that in terms of multispecies fishery management the harvest yield may not accrue as a consequence of predator removal. In addition, this multitude of behaviours points also to the fact that the response of fishery yield to top predator cull may be difficult to assess.

Managing Landscape Irrigation to Avoid Soil and Nutrient Losses

EDIS ◽  
2013 ◽  
Vol 2013 (11) ◽  
Author(s):  
George Hochmuth ◽  
Laurie Trenholm ◽  
Don Rainey ◽  
Esen Momol ◽  
Claire Lewis ◽  
...  
Keyword(s):  
Natural Environment ◽  
Management Practices ◽  
Root Zone ◽  
Irrigation Management ◽  
Critical Factor ◽  
Nutrient Losses ◽  
County Agents ◽  
The Right ◽  
Soil And Water

Proper irrigation management is critical to conserve and protect water resources and to properly manage nutrients in the home landscape. How lawns and landscapes are irrigated directly impacts the natural environment, so landscape maintenance professionals and homeowners must adopt environmentally-friendly approaches to irrigation management. After selecting the right plant for the right place, water is the next critical factor to establish and maintain a healthy lawn and landscape. Fertilization is another important component of lawn and landscape maintenance, and irrigation must be applied correctly, especially following fertilization, to minimize potential nutrient losses. This publication supplements other UF/IFAS Extension publications that also include information on the role of soil and the root zone in irrigation management. This publication is designed to help UF/IFAS Extension county agents prepare materials to directly address nutrient losses from lawns and landscapes caused by inadequate irrigation management practices. This 6-page fact sheet was written by George Hochmuth, Laurie Trenholm, Don Rainey, Esen Momol, Claire Lewis, and Brian Niemann, and published by the UF Department of Soil and Water Science, October 2013. http://edis.ifas.ufl.edu/ss586

The role of collective identifications in family processes of post-trauma reconstruction: An exploratory study with Kurdish refugee families and their diasporic community

2017 ◽  
Vol 5 (2) ◽  
pp. 107-133 ◽  
Author(s):  
Ruth Kevers ◽  
Peter Rober ◽  
Lucia De Haene
Keyword(s):  
Thematic Analysis ◽  
Exploratory Study ◽  
Meaning Making ◽  
Family Processes ◽  
Small Scale ◽  
Refugee Families ◽  
Family Contexts ◽  
Diasporic Community ◽  
And Coping

While collective identifications of diasporic Kurds have attracted considerable scholarly interest, their possible role in familial processes of post-trauma reconstruction has hardly been studied. The aim of this article is therefore to develop an explorative understanding of the deployment and meaning of collective identifications in intimate family contexts by examining the interconnectedness between the transmission of cultural and political belonging and post-trauma meaning-making and coping in Kurdish refugee families. After contextualising diasporic Kurds’ collective identifications through an ethnographic depiction of the Kurdish diasporic community in Belgium, this article reports on findings from a small-scale, exploratory study with five Kurdish refugee families in Belgium. Thematic analysis of family and parent interviews indicates how cultural and political identifications may operate as sources of (1) dealing with cultural bereavement and loss; (2) commemorating trauma; and (3) reversing versus reiterating trauma. Overall, this study’s findings support an explorative understanding of collective identifications as meaningful resources in families’ post-trauma reconstruction.ABSTRACT IN KURMANJIRola nasnameyên komelî di pêvajoyên malbatî yên vesazkirina paş-trawmayê de: Xebateke raveker li ser malbatên kurd ên penaber û civakên wan ên dîasporayêTevî ku nasnameyên komelî yên kurdên dîasporayê ta radeyeke baș bûye mijara lêkolînan, rola wan a muhtemel di pêvajoyên malbatî yên vesazkirina (selihandin) paş-trawmayê qet nehatine vekolîn. Lewma armanca vê gotarê ew e têgihiştineke raveker pêş bixe li ser rol û wateya nasnameyên komelî yên di çarçoveya mehremiya malbatê de, ku vê yekê jî dê bi rêya vekolîna wê têkiliya rijd bike ya di navbera neqlkirina aidiyetên çandî-siyasî û rêyên sazkirina wateyê û serederîkirina li dû trawmayê di nav malbatên kurd ên penaber de. Piştî diyarkirina çarçoveya nasnameya komelî ya Kurdên diasporayê bi rêya teswîreke etnografîk a cemaeta diasporaya Kurd li Belçîkayê, ev gotar encamên ji xebateke biçûk a bi pênc malbatên kurd ên penaber ên li Belçîkayê pêşkêş dike. Tehlîla babetî ya hevpeyvînên ligel malbatan û dayik û bavan nîşan dide ka çawa nasnameyên çandî û siyasî dikarin bibin çavkanî ji bo (1) serederîkirina bi mehrûmiyeta çandî û windahiyên xwe; (2) bibîranîna trawmayê; û (3) kêmrengkirin an, beramber vê yekê, dubarekirina trawmayê. Bi giştî, encamên vê xebatê wê têgihiştineke raveker tesdîq dikin ku nasnameyên kolektîf çavkaniyên kêrhatî ne di vesazkirina paş-trawmayê ya malbatan de. ABSTRACT IN SORANIDewrî nasname bekomellekan le prose binemalleyîyekanî sazkirdinewey paş-trawmayîda: lêkollîneweyekî şirovekarî binemalle penabere kurdekan û civatî ewan le diyasporaLe katêkda nasname bekomellekanî kurdekanî diyaspora le layen şarezakanewe giringîyekî berçawî pê drawe û serincî ewanî bo lay xoyî rakêşawe, bellam sebaret be egerî dewrî prose binemalleyîyekanî sazkirdinewey paş-tirawma be degmen lêkollîneweyek encam drawe. Ke wate, amancî em wutare perepêdan be têgeyîştinêkî şirovekarane lemerr bekarhênan û manay nasname bekomellekan le bestênekanî têkellawîy binemalleyîdaye, ke le rêgey peywendîy nêwan rewtî gwastineweyî grêdraweyî kultûrî û siyasî, sazbûnî mana û herweha rahatin legell kêşekanî qonaẍî paş tirawma le binemalle kurde penaberekanda taqî krawetewe. Dway awirrdanewe le civakî diyasporay kurd le Belcîka, nasname bekomellekanî kurdekanî diyaspora le bestênî xoyda xwêndinewey bo krawe û bem gêreye lem wutareda lêkollîneweyekî şirovekarane bo qebareyekî biçûk le pênc binemalley kurdî penaber le Belcîka dekrê û encamekanî billaw dekrêtewe. Şîkarîyekî babetiyaney wutuwêj legell binemalle û dayk û bawkekan nîşanî dedat ke çon dekrê nasname kultûrî û siyasîyekan wek serçaweyek bo em sê mijare derbikewn: (1) gîrodebûn be ledestçûn û bizirbûnî kultûr; (2) webîrhênanewey tirawma; û (3) pêçewanebûnî tirawma leberamber dûbarebûneweyda. Beşêweyekî giştî, encamekanî em lêkollîneweye piştgîrî le têgeyîştinêkî şirovekarane le nasname bekomellekan dekat ke wekû serçaweyekî giring bo sazkirdinewey binemallekan le dway qonaẍî paş-tirawma seyr dekrêt.

Testing ecological release as a compensating mechanism for mass mortality in a keystone predator

2020 ◽  
Vol 637 ◽  
pp. 59-69 ◽  
Author(s):  
J Sullivan-Stack ◽  
BA Menge
Keyword(s):  
Community Dynamics ◽  
Limiting Factor ◽  
Sea Star ◽  
Top Predator ◽  
Oregon Coast ◽  
Ecological Release ◽  
Keystone Predator ◽  
Pisaster Ochraceus ◽  
Wasting Syndrome

Top predator decline has been ubiquitous across systems over the past decades and centuries, and predicting changes in resultant community dynamics is a major challenge for ecologists and managers. Ecological release predicts that loss of a limiting factor, such as a dominant competitor or predator, can release a species from control, thus allowing increases in its size, density, and/or distribution. The 2014 sea star wasting syndrome (SSWS) outbreak decimated populations of the keystone predator Pisaster ochraceus along the Oregon coast, USA. This event provided an opportunity to test the predictions of ecological release across a broad spatial scale and determine the role of competitive dynamics in top predator recovery. We hypothesized that after P. ochraceus loss, populations of the subordinate sea star Leptasterias sp. would grow larger, more abundant, and move downshore. We based these predictions on prior research in Washington State showing that Leptasterias sp. competed with P. ochraceus for food. Further, we predicted that ecological release of Leptasterias sp. could provide a bottleneck to P. ochraceus recovery. Using field surveys, we found no clear change in density or distribution in Leptasterias sp. populations post-SSWS, and decreases in body size. In a field experiment, we found no evidence of competition between similar-sized Leptasterias sp. and P. ochraceus. Thus, the mechanisms underlying our predictions were not in effect along the Oregon coast, which we attribute to differences in habitat overlap and food availability between the 2 regions. Our results suggest that response to the loss of a dominant competitor can be unpredictable even when based in theory and previous research.

GOELRO plan is 100 years old

2020 ◽  
Vol 12 (12) ◽  
pp. 4-9
Author(s):  
Pavel A. BUTYRIN ◽  
Keyword(s):  
Agricultural Production ◽  
Historical Context ◽  
Soviet Period ◽  
Small Scale ◽  
Efficient Production ◽  
Soviet Republic ◽  
Starting Conditions ◽  
Per Capita ◽  
State Plan

The historical context in which the State Plan for Electrification of Russia (GOELRO) was developed, establishment of the GOELRO Commission, the GOELRO Plan content, the specific features of its implementation, and the role of the plan in the soviet period of Russia’s history are considered. Attention is paid to the electrification plants of other countries and territories of all inhabited continents, and to the participation of states in the electrification of countries and regions with small-scale and agricultural production in the 1920 s. The specific features pertinent to the electrification of the Russian Socialist Federative Soviet Republic are pointed out, namely, low starting conditions (in 1923, the energy consumption per capita in Russia was 100 times lower than that in Norway), its being state-owned in nature and revolutionary in its purpose: to get done with the main upheavals in the country and to shift the national economy for fore efficient production. The role of V.I. Lenin and G.M. Krzhizhanovsky, who were the initiators of the electrification of Russia, is analyzed in detail. A conclusion is drawn about the need to study both the GOELRO Plan itself and the specific features and circumstances of its implementation within the framework of training modern specialists in electrical engineering.

scholarly journals The Role of the Reactive Species Involved in the Photocatalytic Degradation of HDPE Microplastics Using C,N-TiO2 Powders

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 999 ◽  
Author(s):  
Aranza Denisse Vital-Grappin ◽  
Maria Camila Ariza-Tarazona ◽  
Valeria Montserrat Luna-Hernández ◽  
Juan Francisco Villarreal-Chiu ◽  
Juan Manuel Hernández-López ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Reaction System ◽  
Terrestrial Ecosystems ◽  
Degradation Process ◽  
Reactive Species ◽  
Hazardous Substances ◽  
Wide Range ◽  
Degradation Behaviors ◽  
Environmentally Friendly Process

Microplastics (MPs) are distributed in a wide range of aquatic and terrestrial ecosystems throughout the planet. They are known to adsorb hazardous substances and can transfer them across the trophic web. To eliminate MPs pollution in an environmentally friendly process, we propose using a photocatalytic process that can easily be implemented in wastewater treatment plants (WWTPs). As photocatalysis involves the formation of reactive species such as holes (h+), electrons (e−), hydroxyl (OH●), and superoxide ion (O2●−) radicals, it is imperative to determine the role of those species in the degradation process to design an effective photocatalytic system. However, for MPs, this information is limited in the literature. Therefore, we present such reactive species’ role in the degradation of high-density polyethylene (HDPE) MPs using C,N-TiO2. Tert-butanol, isopropyl alcohol (IPA), Tiron, and Cu(NO3)2 were confirmed as adequate OH●, h+, O2●− and e− scavengers. These results revealed for the first time that the formation of free OH● through the pathways involving the photogenerated e− plays an essential role in the MPs’ degradation. Furthermore, the degradation behaviors observed when h+ and O2●− were removed from the reaction system suggest that these species can also perform the initiating step of degradation.

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