scholarly journals Darwin’s naturalization conundrum disentangled: the role of phylogenetic relatedness depends on the invasion stages

2021 ◽  
Author(s):  
Ali Omer ◽  
Trevor Fristoe ◽  
Qiang Yang ◽  
Mialy Razanajatovo ◽  
Patrick Weigelt ◽  
...  
Keyword(s):  
Alien Species ◽  
Southern Africa ◽  
Native Species ◽  
Phylogenetic Distance ◽  
Phylogenetic Relatedness ◽  
Native Flora ◽  
Invasion Stage ◽  
Adaptation Hypothesis ◽  
The Relationship

Abstract Darwin’s naturalization hypothesis predicts successful invaders to be distantly related to native species, whereas his pre-adaptation hypothesis predicts the opposite. It has been suggested that depending on the invasion stage (i.e. introduction, naturalization, and invasiveness), both hypotheses, now known as Darwin’s naturalization conundrum, could hold true. We tested this by analysing whether the likelihood of introduction for cultivation as well as subsequent stages of naturalization and invasion of species alien to Southern Africa are correlated with their phylogenetic distance to the native flora of this region. While species were more likely to be introduced for cultivation if they are distantly related to the native flora, the probability of subsequent naturalization was higher for species closely related to the native flora. Furthermore, the probability of becoming invasive was higher for naturalized species distantly related to the native flora. These results were consistent across three different metrics of phylogenetic distance. Our study reveals that the relationship between phylogenetic distance to the native flora and success of an alien species depends on the invasion stage.

scholarly journals Church asMbumbaand Bishop asNkhoswe: Anglican Ecclesiology and Missiological Imperatives in Central Africa

2016 ◽  
Vol 14 (2) ◽  
pp. 172-191
Author(s):  
Henry Mbaya
Keyword(s):  
Southern Africa ◽  
Central Africa ◽  
Critical Values ◽  
The Relationship

AbstractThis paper explores the use of the Chewa and Nyanja concepts ofmbumbaandnkhoswein Central Africa and Southern Africa as interpretive tools for an Anglican ecclesiology and theology of leadership. Following an exposition of these two concepts, it conceptualizesmbumbaas a diocese, and bishops asnkhoswederiving from Christ asNkhoswepar excellence. These two concepts entail critical values including responsibility, accountability and mutuality, which can be used as a model to enhance the relationship between a diocese and bishop. Conceptualizing a diocese asmbumbaand the role of a bishop as that ofnkhoswehas the potential to enhance missional practice in Central and Southern Africa.

scholarly journals Alien Species vs. Native Species: From Community Ecology to Eco-Evolutionary Dynamics

2019 ◽  
Author(s):  
Andersonn Silveira Prestes
Keyword(s):  
Alien Species ◽  
Exotic Species ◽  
Native Species ◽  
Evolutionary Dynamics ◽  
Evolutionary Processes ◽  
Native Communities ◽  
Individualized Approach ◽  
History Of ◽  
Relationship Of ◽  
The Relationship

The establishment and spread of exotic species is a contemporary major concern. Alien species may become invasive in their new habitat, leading to both/either environmental and/or economic impacts. I briefly reviewed the literature in the last decade about the relationship of exotic species and native communities. I identified that professionals usually approach the subject in two main points of view: (1) researchers tend to point out the impacts of alien species on entire communities, evaluating if the relationship is positive, negative or neutral; (2) they focus on the eco-evolutionary processes involved in the introductions, the dynamics of invasion, and individual study cases. When evaluating the response of introductions to entire communities, evidence seems to be ambiguous and may support positive, negative or neutral relationship, especially depending on the scale approached. The unique eco-evolutionary pathways of each introduction may be a great shortcoming in the searching for generalities. On the other hand, advances have been made in understanding the dynamics of invasion on different lineages through a more selective/individualized approach. I suggest that the dynamics of invasion might be studied through a perspective in which different eco-evolutionary processes, levels of organization (from gene to entire communities), the history of the organism(s) and time are taken into account. Individual cases might be compared in attempt to understand how the relationship exotic and native works and in the search for generalities.

Scale dependence in the phylogenetic relatedness of alien and native taxa

2020 ◽  
Vol 13 (5) ◽  
pp. 601-610
Author(s):  
Chris M McGrannachan ◽  
Gillis J Horner ◽  
Melodie A McGeoch
Keyword(s):  
Alien Species ◽  
Spatial Scale ◽  
Native Species ◽  
Spatial Scales ◽  
Pairwise Distance ◽  
Phylogenetic Structure ◽  
Phylogenetic Clustering ◽  
Phylogenetic Relatedness ◽  
Darwin's Naturalization Hypothesis ◽  
Darwin’S Naturalization Hypothesis

Abstract Aims Darwin’s naturalization hypothesis proposes that successfully established alien species are less closely related to native species due to differences in their ecological niches. Studies have provided support both for and against this hypothesis. One reason for this is the tendency for phylogenetic clustering between aliens and natives at broad spatial scales with overdispersion at fine scales. However, little is known about how the phylogenetic relatedness of alien species alters the phylogenetic structure of the communities they invade, and at which spatial scales effects may manifest. Here, we examine if invaded understorey plant communities, i.e. containing both native and alien taxa, are phylogenetically clustered or overdispersed, how relatedness changes with spatial scale and how aliens affect phylogenetic patterns in understorey communities. Methods Field surveys were conducted in dry forest understorey communities in south-east Australia at five spatial scales (1, 20, 500, 1500 and 4500 m2). Standardized effect sizes of two metrics were used to quantify phylogenetic relatedness between communities and their alien and native subcommunities, and to examine how phylogenetic patterns change with spatial scale: (i) mean pairwise distance and (ii) mean nearest taxon distance (MNTD). Important Findings Aliens were closely related to each other, and this relatedness tended to increase with scale. Native species and the full community exhibited either no clear pattern of relatedness with increasing spatial scale or were no different from random. At intermediate spatial scales (20–500 m2), the whole community tended towards random whereas the natives were strongly overdispersed and the alien subcommunity strongly clustered. This suggests that invasion by closely related aliens shifts community phylogenetic structure from overdispersed towards random. Aliens and natives were distantly related across spatial scales, supporting Darwin’s naturalization hypothesis, but only when phylogenetic distance was quantified as MNTD. Phylogenetic dissimilarity between aliens and natives increased with spatial scale, counter to expected patterns. Our findings suggest that the strong phylogenetic clustering of aliens is driven by human-mediated introductions involving closely related taxa that can establish and spread successfully. Unexpected scale-dependent patterns of phylogenetic relatedness may result from stochastic processes such as fire and dispersal events and suggest that competition and habitat filtering do not exclusively dominate phylogenetic relationships at fine and coarse spatial scales, respectively. Distinguishing between metrics that focus on different evolutionary depths is important, as different metrics can exhibit different scale-dependent patterns.

Further observations on the relationship and distribution of Schistosoma margrebowiei and S. leiperi in central southern Africa

1977 ◽  
Vol 51 (4) ◽  
pp. 327-336 ◽  
Author(s):  
R. J. Pitchford ◽  
B. Wolstenholme
Keyword(s):  
Southern Africa ◽  
National Park ◽  
Endemic Area ◽  
Skin Tests ◽  
African Buffalo ◽  
Papio Ursinus ◽  
The Past ◽  
Surrounding Areas ◽  
The Relationship

ABSTRACTA further survey in East Caprivi, Chobe National Park, Okavango swamps and Kavango was undertaken in June 1976. No evidence of lechwe schistosomes was found in droppings of African buffalo (Syncerus caffer) nor baboons (Papio ursinus) living in lechwe habitats. It was thought that they were not capable of spreading or maintaining these parasites outside the confines of the known distribution of Kobus sp. The role of goats was equivocal but probably they too are poor hosts.Kavango, an endemic area of S. haematobium and S. mansoni, was thought to be free of all animal schistosomes, thus confirming the hypotheses that (1) cattle and goats are poor hosts of the lechwe schistosomes and (2)S. mattheei was blocked from entering the territory by the presence of lechwe schistosomes in the surrounding areas. Evidence of schistosomes was not found in cattle and goats at Maun for the same reasons. The prevalence of S. mansoni at Maun has increased alarmingly over the past 20 years with a simultaneous disappearance of lechwe from the area. S. margrebowiei and S. leiperi eggs were found in lechwe and tsessebe droppings some 80 km north of Maun.A high proportion of children with negative excreta from “non-endemic” areas in East Caprivi had positive CFT and/or skin tests, suggestive of exposure to lechwe schistosomes resulting in a possible immunity to S. mansoni and S. haematobium.

scholarly journals Patterns in the alien flora of the Democratic Republic of the Congo: a comparison of Asteraceae and Fabaceae

2020 ◽  
Vol 153 (3) ◽  
pp. 373-389
Author(s):  
Farzaneh Bordbar ◽  
Pierre Meerts
Keyword(s):  
Alien Species ◽  
Native Species ◽  
Life Form ◽  
Democratic Republic ◽  
Geographic Origin ◽  
Life Forms ◽  
Trait Divergence ◽  
Native Flora ◽  
Alien Flora ◽  
Republic Of The Congo

Background and aims – This work provides the first pattern analysis of the alien flora of the Democratic Republic of the Congo (D.R. Congo), using Asteraceae and Fabaceae as a case study. Methods – Based on herbarium collections, existing databases, and literature data, a database of 38 alien species of Asteraceae and 79 alien species of Fabaceae has been assembled. Patterns in the introduction pathway, phylogeny, life form, morpho-functional traits, geographic origin, and occurrence in D.R. Congo are explored. Key results – America is the main source continent in both families, but Asia is also an important donor of Fabaceae. Taxonomic spectrum discrepancies between the alien and the native flora reflect the continent of origin. Sixty-six percent of alien Asteraceae have been accidentally introduced, most of which being annual weeds of disturbed soil. In contrast, 90% of alien Fabaceae have been deliberately introduced for forestry, agriculture, or environmental purposes, most of which being phanerophytes. Traits were compared between pairs of congeneric alien and native species. For Asteraceae, a sharp discrepancy was found in the life form spectrum (aliens: mostly therophytes; natives: phanerophytes). For Fabaceae, alien species had larger leaves and larger pods compared to their native congeners. The number of specimens in collections was positively correlated with the time since the date of first collection for both families. The Guineo-Congolian region has the highest number of alien Fabaceae, while alien Asteraceae are overrepresented in the Zambezian region.Conclusions – Contrasting patterns between alien Asteraceae and Fabaceae in the flora of D.R. Congo in terms of life forms, trait divergence compared to the native flora, and occurrence, reflect the divergent biological attributes and relations to humans of the two families. The striking discrepancies between the two families call for analyses of patterns of alien flora at family level and warn against global generalisations.

scholarly journals A review of the diversity and impact of invasive non-native species in tropical marine ecosystems

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Parisa Alidoost Salimi ◽  
Joel C. Creed ◽  
Melanie M. Esch ◽  
Douglas Fenner ◽  
Zeehan Jaafar ◽  
...  
Keyword(s):  
Climate Change ◽  
Coral Reefs ◽  
Alien Species ◽  
Native Species ◽  
Marine Ecosystems ◽  
The Other ◽  
Seagrass Beds ◽  
Native Flora ◽  
Major Threat ◽  
The Status

AbstractTropical marine ecosystems are biologically diverse and economically invaluable. However, they are severely threatened from impacts associated with climate change coupled with localized and regional stressors, such as pollution and overfishing. Non-native species (sometimes referred to as ‘alien’ species) are another major threat facing these ecosystems, although rarely discussed and overshadowed by the other stressors mentioned above. NNS can be introduced accidentally (for example via shipping activities) and/or sometimes intentionally (for aquaculture or by hobbyists). Understanding the extent of the impacts NNS have on native flora and fauna often remains challenging, along with ascertaining when the species in question actually became ‘invasive’. Here we review the status of this threat across key tropical marine ecosystems such as coral reefs, algae meadows, mangroves, and seagrass beds. We aim to provide a baseline of where invasive NNS can be found, when they are thought to have been introduced and what impact they are thought to be having on the native ecosystems they now inhabit. In the appended material we provide a comprehensive list of NNS covering key groups such as macroalgae, sponges, seagrasses and mangroves, anthozoans, bryozoans, ascidians, fishes, and crustaceans.

scholarly journals Effect of Competition from Native on Alien Species in a Multitrophic Setting

2019 ◽  
Author(s):  
Eva Maria Malecore ◽  
Mark van Kleunen
Keyword(s):  
Alien Species ◽  
Plant Species ◽  
Native Species ◽  
Niche Overlap ◽  
Native Plant ◽  
Closely Related Species ◽  
Native Plant Species ◽  
Phylogenetic Relatedness ◽  
Multitrophic Interaction ◽  
Target Plant

1. Darwin’s naturalization hypothesis predicts that alien species closely related to native species are less likely to naturalize because of strong competition due to niche overlap. Closely related species are likely to attract similar herbivores and to release similar plant volatiles following herbivore attack, thus could attract the same predators. However, the importance of phylogenetic relatedness on the interaction between alien and native plants has never been tested in a multitrophic context. 2. In a mesocosm experiment we grew six alien target plant species alone and in competition with nine native plant species of varying phylogenetic relatedness. To test the effects of multitrophic interactions on the performance of alien target species, we used enclosure cages to expose plants to the presence and absence of herbivorous arthropods, predatory arthropods and nematodes. 3. Surprisingly, biomass and number of flowering structures increased with presence of competitors for some of the alien species, but overall there was no consistent competition effect. Similarly, we found that none of the multitrophic-interaction treatments affected survival, biomass or number of flowering structures of the alien species. 4. We conclude there was no significant relationship between performance measures of the alien species and their phylogenetic relatedness to the native competitors.

scholarly journals Species coexistence: macroevolutionary relationships and the contingency of historical interactions

2016 ◽  
Vol 283 (1827) ◽  
pp. 20160047 ◽  
Author(s):  
Rachel M. Germain ◽  
Jason T. Weir ◽  
Benjamin Gilbert
Keyword(s):  
Phylogenetic Relationships ◽  
Native Species ◽  
Species Coexistence ◽  
Recent Theory ◽  
Phylogenetic Distance ◽  
Closely Related Species ◽  
Allopatric Species ◽  
Species Pairs ◽  
Annual Plant Species

Evolutionary biologists since Darwin have hypothesized that closely related species compete more intensely and are therefore less likely to coexist. However, recent theory posits that species diverge in two ways: either through the evolution of ‘stabilizing differences’ that promote coexistence by causing individuals to compete more strongly with conspecifics than individuals of other species, or through the evolution of ‘fitness differences’ that cause species to differ in competitive ability and lead to exclusion of the weaker competitor. We tested macroevolutionary patterns of divergence by competing pairs of annual plant species that differ in their phylogenetic relationships, and in whether they have historically occurred in the same region or different regions (sympatric versus allopatric occurrence). For sympatrically occurring species pairs, stabilizing differences rapidly increased with phylogenetic distance. However, fitness differences also increased with phylogenetic distance, resulting in coexistence outcomes that were unpredictable based on phylogenetic relationships. For allopatric species, stabilizing differences showed no trend with phylogenetic distance, whereas fitness differences increased, causing coexistence to become less likely among distant relatives. Our results illustrate the role of species' historical interactions in shaping how phylogenetic relationships structure competitive dynamics, and offer an explanation for the evolution of invasion potential of non-native species.

International Sanctions: A Framework for Analysis with Special Reference to the UN and Southern Africa

1972 ◽  
Vol 26 (3) ◽  
pp. 527-550 ◽  
Author(s):  
Margaret Doxey
Keyword(s):  
South Africa ◽  
International Economic ◽  
United Nations ◽  
Special Reference ◽  
Southern Africa ◽  
Economic Sanctions ◽  
The Status ◽  
International Sanctions ◽  
The Relationship

This paper falls into two main parts. In Part I an attempt is made to develop a simple framework which can be used for analyzing the role of sanctions, with special reference to international sanctions.1In Part II this framework is used to investigate the status of the United Nations as a sanctioning body and, in particular, the relationship between the UN and Southern Africa where Rhodesia has been subjected to international economic sanctions since 1965 and South Africa has been under threat of similar measures since the early 1960s.2

scholarly journals Phylogenetic Diversity of Urban Floras in the Central Urals

2021 ◽  
Vol 9 ◽  
Author(s):  
Alyona S. Tretyakova ◽  
Basil N. Yakimov ◽  
Pavel V. Kondratkov ◽  
Nickolay Yu. Grudanov ◽  
Marc W. Cadotte
Keyword(s):  
Alien Species ◽  
Urban Areas ◽  
Native Species ◽  
Phylogenetic Diversity ◽  
Indigenous Species ◽  
Phylogenetic Distance ◽  
Full Spectrum ◽  
Modern Cities ◽  
Urban Floras ◽  
Central Urals

Modern cities harbor a high diversity of plants, and urban floras are significantly different from non-urban floras especially when considering the proportion of alien species found in cities. However, it is not clear whether urban areas disproportionately select for species from relatively few evolutionary lineages or provide opportunities for species across the full spectrum of plant lineages. Here, we examined the taxonomic and phylogenetic diversity of the floras in four cities (Yekaterinburg, Kamensk-Uralsky, Krasnoufimsk, and Turinsk) in the understudied region of Central Urals (Russian Federation). We classified native species into indigenous and apophytic species, namely, those that are sensitive to anthropogenic disturbance and those that have expanded their range with human activity, respectively. Alien species were classified into archaeophytes and neophytes according to when they were introduced (i.e., before or after than 1800). Phylogenetic diversity was quantified using Faith’s index to reflect total evolutionary history in urban areas and mean phylogenetic distance (MPD) to reflect species dissimilarity. Phylogenetic diversity of native species was higher than that for alien species, and the standardized effect size (SES) of MPD for natives was positive, reflecting their general dissimilarity from one another, while it was very negative for aliens, showing that they were phylogenetically clustered. However, among natives, apophytes were significantly clustered, while indigenous species were overdispersed. For the aliens, MPD was higher for archaeophytes compared to neophytes, though both groups were significantly clustered. These results show that urbanization leads to a non-random selection of plants. Apophytes and alien plants were composed of closely related species, reflecting similar ecological traits and are likely to be pre-adapted to the environmentally altered and highly disturbed urban environment.

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