scholarly journals Cucumis dipsaceus (hedgehog gourd).

Author(s):  
Shruti Dube

Abstract Cucumis dipsaceus is an annual climbing herb native to Africa and the Arabian Peninsula that has become invasive in many regions around the world where it spread or was introduced. In Mexico, this species is possibly expanding and is classified as an invasive. In the Galapagos Islands C. dipsaceus has invaded a large area and is affecting the natural ecosystem by altering community composition and threatening native species.

2020 ◽  
Author(s):  
Shruti Dube

Abstract Cucumis dipsaceus is an annual climbing herb native to Africa and the Arabian Peninsula that has become invasive in many regions around the world where it spread or was introduced. In Mexico, this species is possibly expanding and is classified as an invasive. In the Galapagos Islands C. dipsaceus has invaded a large area and is affecting the natural ecosystem by altering community composition and threatening native species.


Bionatura ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 1427-1433
Author(s):  
Camila Velastegui ◽  
Mary Pulgar-Sánchez ◽  
Kevin Chamorro

The Galapagos Islands are well known for their incredible biodiversity and the inspiration for Charles Darwin's natural evolution theory. It is an ecosystem that has evolved without predators, so their native species are unfit for competition. As a result, this biodiversity has been threatened by invasive species like rats (Black and Norwegian). Nowadays, the primary strategy to control rats is by having drones that disperse a unique poisoned bait. Our study aims to mathematically model the strategies to eradicate rats in islands, based on previously reported processes. As a result, we are obtaining the approximated time to reduce its population as much as being eradicated, without threatening the coexisting species. We also propose a suitable alternative to be applied in the Galapagos Islands to recover their biodiversity richness. We find that rats' introduction has caused a decrease in the native species due to having specific traits that make them fitter in different situations. The best method to control species in such a sensitive environment is by the use of anticoagulant rodenticides. The current method used for eradicating rats seems to be the most profitable even though there is not enough information to see the collateral consequences of the poison technique. Furthermore, we propose this theoretical study complemented with in situ samplings to corroborate our hypothesis and improve our prediction model.


2018 ◽  
Author(s):  
Diego F Cisneros-Heredia

Humans have translocated thousands of species of flora, fauna and microorganisms to places they would never have reached on their own. Non-native species may have effects on biological communities, ecosystem functions and human populations. In island environments, the effects of spreading non-native species on native biodiversity can be severe and lead to native ecosystem transformation and even endemic species extinction. The Galapagos Islands are a region of particular interest and relevance to the issue of species introduction and invasiveness. In this paper, I analyse the current status of 25 non-native amphibians, reptiles and birds that have been reported in the Galapagos Islands. Six species have established self-sufficiently in Galapagos and may become invasive: Fowler’s snouted tree frog Scinax quinquefasciatus, common house gecko Hemidactylus frenatus, mourning gecko Lepidodactylus lugubris, dwarf gecko Gonatodes caudiscutatus, Peters’ leaf-toed gecko Phyllodactylus reissii, and smooth-billed ani Crotophaga ani. Domestic fowl Gallus gallus holds feral populations, which may have self-sufficient populations, but evidence is unclear. I provide information on the distribution and natural history of non-native species of amphibians, reptiles and birds in Galapagos, including new data about the introduction history of S. quinquefasciatus; evidence on the establishment of H. frenatus on Isabela and San Cristobal islands; the first published record of a non-native snake in Galapagos, Lampropeltis micropholis; the first evidence of predation on squamate reptiles by G. gallus in Galapagos; and evidence of a probable major impact by C. ani due to extensive predation on the endemic Galapagos carpenter bee Xylocopa darwini. I comment on the invasiveness and impact potential of non-native species in Galapagos, identify vulnerable islands for the arrival of non-native species, identify potential hitchhiker that could arrive in the future and propose that it is important to rethink about how we understand, manage and prevent introductions of non-native species. The new wave of introduced species in Galapagos is formed by small hitchhikers, species that are easily overlooked, may travel in high numbers and are highly linked to human-made environments.


Author(s):  
Peter V. N. Henderson

The Galápagos Islands, long acknowledged as Darwin’s “Living Laboratory,” are one of the world’s most important ecological treasures. From their discovery in 1535 until the creation of the Galápagos National Park in 1959, human hands touched lightly on their shores. Seemingly incapable of sustaining colonization because of poor soil, a scarcity of water, and no mineral wealth, the absence of humans allowed the native species of the Galápagos to remain undisturbed until whalers in the 1790s found that the lumbering Galápagos tortoises could be stored for months in their ship’s holds as a source of fresh meat. In 1832 Ecuador took possession of the archipelago but its colonization efforts generally failed. Although human settlement remained minimal, mammals that people brought (goats, donkeys, pigs, dogs, and cats) flourished and diminished the numbers of the endemic species. When the Galápagos National Park opened, only about 2,000 people lived on the islands along with the remaining endemic species and hundreds of thousands of feral animals. Meanwhile, naturalist Charles Darwin’s remarkable 1859 study, On the Origins of Species had stimulated biologists’ interest in the islands’ wildlife by presenting overwhelming proof of evolution. Other biologists questioned his idea of natural selection as the mechanism behind evolution; consequently they gathered evidence from collected specimens and observations in the archipelago, and finally resolved the debate in Darwin’s favor. After 1990, popular interest in the islands’ wildlife heightened as a result of photography, travelers’ accounts, and films, so tourism increased as did the number of Ecuadorian immigrants eager to earn money in the tourist industry. By 2020, Ecuadorian authorities faced the dilemma of balancing the need to preserve the unique species and their fragile environment against the revenue generated by visitors, a battle environmentalists fear the government is losing.


2017 ◽  
Vol 32 (3) ◽  
pp. 424-449 ◽  
Author(s):  
Paolo Bocci

If calls to care for other species multiply in a time of global and local environmental crisis, this article demonstrates that caring practices are not always as benevolent or irenic as imagined. To save endemic tortoises from the menace of extinction, Proyecto Isabela killed more than two hundred thousand goats on the Galápagos Islands in the largest mammal eradication campaign in the world. While anthropologists have looked at human engagements with unwanted species as habitual and even pleasurable, I discuss an exceptional intervention that was ethically inflected toward saving an endemic species, yet also controversial and distressing. Exploring eradication’s biological, ecological, and political implications and discussing opposing practices of care for goats among residents, I move past the recognition that humans live in a multispecies world and point to the contentious nature of living with nonhuman others. I go on to argue that realizing competing forms of care may help conservation measures—and, indeed, life in the Anthropocene—to move beyond the logic of success and failure toward an open-ended commitment to the more-than-human.


2020 ◽  
Author(s):  
Matthew J.S. Gibson ◽  
María de Lourdes Torres ◽  
Yaniv Brandvain ◽  
Leonie C. Moyle

AbstractThe introduction of non-native species into new habitats is one of the foremost risks to global biodiversity. Here, we evaluate a recent invasion of wild tomato (Solanum pimpinellifolium) onto the Galápagos islands from a population genomic perspective, using a large panel of novel collections from the archipelago as well as historical accessions from mainland Ecuador and Peru. We infer a recent invasion of S. pimpinellifolium on the islands, largely the result of a single event from central Ecuador which, despite its recency, has rapidly spread onto several islands in the Galápagos. By reconstructing patterns of local ancestry throughout the genomes of invasive plants, we uncover evidence for recent hybridization and introgression between S. pimpinellifolium and the closely related endemic species Solanum cheesmaniae. Two large introgressed regions overlap with known fruit color loci involved in carotenoid biosynthesis. Instead of red fruits, admixed individuals with endemic haplotypes at these loci have orange fruit colors that are typically characteristic of the endemic species. We therefore infer that introgression explains the observed trait convergence. Moreover, we infer roles for two independent loci in driving this pattern, and a likely history of selection favoring the repeated phenotypic transition from red to orange fruits. Together, our data reconstruct a complex history of invasion, expansion, and gene flow among wild tomatoes on the Galápagos islands. These findings provide critical data on the evolutionary importance of hybridization during colonization and its role in influencing conservation outcomes.Significance StatementThe isolation and unique diversity of the Galápagos Islands provide numerous natural experiments that have enriched our understanding of evolutionary biology. Here we use population genomic sequencing to reconstruct the timing, path, and consequences of a biological invasion by wild tomato onto the Galápagos. We infer that invasive populations originated from a recent human-mediated migration event from central Ecuador. Our data also indicate that invasive populations are hybridizing with endemic populations, and that this has led to some invasive individuals adopting both fruit color genes and the fruit color characteristic of the endemic island species. Our results demonstrate how hybridization can shape patterns of trait evolution over very short time scales, and characterize genetic factors underlying invasive success.


2018 ◽  
Author(s):  
Diego F Cisneros-Heredia

Humans have translocated thousands of species of flora, fauna and microorganisms to places they would never have reached on their own. Non-native species may have effects on biological communities, ecosystem functions and human populations. In island environments, the effects of spreading non-native species on native biodiversity can be severe and lead to native ecosystem transformation and even endemic species extinction. The Galapagos Islands are a region of particular interest and relevance to the issue of species introduction and invasiveness. In this paper, I analyse the current status of 25 non-native amphibians, reptiles and birds that have been reported in the Galapagos Islands. Six species have established self-sufficiently in Galapagos and may become invasive: Fowler’s snouted tree frog Scinax quinquefasciatus, common house gecko Hemidactylus frenatus, mourning gecko Lepidodactylus lugubris, dwarf gecko Gonatodes caudiscutatus, Peters’ leaf-toed gecko Phyllodactylus reissii, and smooth-billed ani Crotophaga ani. Domestic fowl Gallus gallus holds feral populations, which may have self-sufficient populations, but evidence is unclear. I provide information on the distribution and natural history of non-native species of amphibians, reptiles and birds in Galapagos, including new data about the introduction history of S. quinquefasciatus; evidence on the establishment of H. frenatus on Isabela and San Cristobal islands; the first published record of a non-native snake in Galapagos, Lampropeltis micropholis; the first evidence of predation on squamate reptiles by G. gallus in Galapagos; and evidence of a probable major impact by C. ani due to extensive predation on the endemic Galapagos carpenter bee Xylocopa darwini. I comment on the invasiveness and impact potential of non-native species in Galapagos, identify vulnerable islands for the arrival of non-native species, identify potential hitchhiker that could arrive in the future and propose that it is important to rethink about how we understand, manage and prevent introductions of non-native species. The new wave of introduced species in Galapagos is formed by small hitchhikers, species that are easily overlooked, may travel in high numbers and are highly linked to human-made environments.


2021 ◽  
Vol 14 (1) ◽  
pp. 20-28
Author(s):  
Jorge L. Renteria ◽  
Rachel Atkinson ◽  
Claudio Crespo ◽  
Mark R. Gardener ◽  
Edwin D. Grosholz

AbstractStrong competitive ability of introduced plant species has been frequently stated as a key factor promoting successful invasion. The dynamics of invasive species may depend on their abilities to compete for resources and exploit disturbances relative to native species. This study compares the growth performance of the invasive blackberry (Rubus niveus Thunb.) with four of the most common woody native species of the Scalesia forest in the Galapagos Islands. Using a series of greenhouse and field studies, the growth rate and biomass production of native species alone and in competition with R. niveus was compared under different water and light stress conditions. Rubus niveus showed a faster growth rate and biomass production than the native species as well as a broad tolerance to light and water stress conditions. Competitive ability was also assessed by looking at the seedbank and regeneration processes after herbicide control in the field. Although the number of R. niveus seedlings that germinated from the soil samples was considerably larger than that of native species, recruitment of the invasive on the experimental plots was limited. Overall, R. niveus showed superior competitive ability over native species with comparable growth forms, suggesting a possible mechanism that enables R. niveus to successfully invade a wide range of habitats in the Galapagos Islands. Implementing an integrated management strategy including biological control, seedbank reduction, and active revegetation, should improve the efficiency of R. niveus management, enabling the restoration of degraded vegetation in the Galapagos.


Author(s):  
Malik Daham Mata’ab

Oil has formed since its discovery so far one of the main causes of global conflict, has occupied this energy map a large area of conflict the world over the past century, and certainly this matter will continue for the next period in our century..


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