Habitat use and ecological interactions of an introduced and a native species of Anolis lizard on Grand Cayman, with a review of the outcomes of anole introductions
TL;DR: Review of data concerning 23 Anolis introductions indicates that the presence or absence of an ecologically similar native species may be an important determinant of colonization success or failure.
Abstract: Since its introduction ten years ago, Anolis sagrei has spread over much of Grand Cayman and is now more common in some habitats than the native anole, A. conspersus. Interspecific differences in body size, perch height, and microclimatic preference may have facilitated the colonization. Nonetheless, competition may be occurring between the species; comparisons with studies of habitat use prior to the arrival of A. sagrei indicate that in open habitats, where A. sagrei is now abundant, A. conspersus perches higher, but in closed habitats, where A. sagrei is absent, no change in perch height is evident. Review of data concerning 23 Anolis introductions indicates that the presence or absence of an ecologically similar native species may be an important determinant of colonization success or failure.
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TL;DR: It is proposed that ancestral species in the Greater Antilles may have been trunk-crown anoles, although some species exhibit morphologies unlike those seen in Greater Antillean species.
Abstract: On the large islands of the Greater Antilles, multi-species communities ofAnolislizards are composed of species specialized to use particular habitats; similar sets of specialized species have evolved independently on each island. We studied species of anoles found on small Caribbean islands. Because these islands contain at most only one other species of anole, we predicted that species on these islands should not be as specialized as Greater Antillean species; rather, they might be expected to exhibit a generalized morphology and a greater breadth of habitat use. Our findings, however, do not confirm these predictions. Lesser Antillean species do not exhibit greater breadth of habitat use than Greater Antillean species, nor do they exhibit a generalized morphology. Most species are ecologically and morphologically similar to specialized trunk-crown anoles of the Greater Antilles, although some species exhibit morphologies unlike those seen in Greater Antillean species. Among descendants of specialized Greater Antillean species occurring on one- or two-species islands, most descendants of trunk-crown species have diverged relatively little, whereas several descendants of trunk-ground anoles have diverged considerably. Consequently, we propose that ancestral species in the Greater Antilles may have been trunk-crown anoles.
118 citations
TL;DR: This article examined populations of two species of Anolis lizards that evolved in the species-rich communities of Cuba and are now widespread in the Bahamas and found that none of the populations appears to have differentiated from its ancestral "ecomorph" type toward a more generalized morphology.
Abstract: Interspecific interactions affect habitat use and subsequent morphological adaptation in Anolis lizards. We examined populations of two species of Anolis lizards that evolved in the species-rich communities of Cuba and are now widespread in the Bahamas. Because the species occupy islands in the Bahamas that vary in the number of lizard species present and other characteristics, we predicted that directional selection should have led to morphological differentiation. In particular, we expected that populations on one-species islands should have evolved toward a generalist morphology because of the lack of competitors. Divergence in both species has been adaptive; populations that use wider perches have longer legs. Nonetheless, these differences are relatively minor, and none of the populations appears to have differentiated from its ancestral "ecomorph" type toward a more generalized morphology. This stasis mirrors a trend observed in the radiation of Caribbean anoles, which exhibits repeated instances of evolutionary specialization, but few or no cases of reversion to a more generalized condition. The explanation for this directionality of evolution is not obvious but probably involves the tendency of specialized species to continue using and further adapting the niches for which they are specialized even as conditions change.
117 citations
TL;DR: This work ran a seven-year experiment on an entirely natural system of small islands, using the commonest local lizard as the predator and web spiders as prey, and found that locally common and rare species were both reduced by the introduction of lizards, but nearly all of the latter became permanently extinct.
Abstract: HISTORICAL ecology contains various examples of how predators introduced onto islands by man have apparently exterminated native prey species1–6. Conversely, a pioneering experiment7 showed an increase in number of species with predator presence. Subsequent experiments have shown both increases and decreases in prey diversity8–10. Here we investigate how predator introduction affects one aspect of prey diversity (number of species or species richness), and prey abundance. We ran a seven-year experiment on an entirely natural system of small islands, using the commonest local lizard as the predator and web spiders as prey. Lizard introduction caused rapid and devastating effects on spider diversity and abundance: within two years, islands onto which lizards had been introduced became almost identical to islands with natural lizard populations. The proportion of species becoming extinct was 12.6 times higher on lizard-introduction' islands than on islands without lizards. Locally common and rare species were both reduced by the introduction of lizards, but nearly all of the latter became permanently extinct.
115 citations
TL;DR: Findings support the hypothesis that H. frenatus led to the fragmentation and extinction of the endemic Nactus populations and demonstrate that artificial refugia made of a crumbly substrate may be used to limit future disturbances by this gecko and others like it in the Mascarene Islands and elsewhere.
111 citations
Cites background from "Habitat use and ecological interact..."
...However, given the increasing rate at which reptiles are being introduced around the world, and increasing evidence that they may have signiWcant competitive impacts on resident species, we need to understand the role of competition in driving extinction events (Rodda and Fritts, 1992; Losos et al., 1993; McCoid, 1993; Case et al., 1992, 1994; Petren and Case, 1998; Losos and Spiller, 1999; Brown et al., 2002)....
[...]
...…that they may have signiWcant competitive impacts on resident species, we need to understand the role of competition in driving extinction events (Rodda and Fritts, 1992; Losos et al., 1993; McCoid, 1993; Case et al., 1992, 1994; Petren and Case, 1998; Losos and Spiller, 1999; Brown et al., 2002)....
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01 Jan 1998
TL;DR: The fossil record of the earth shows that faunal and floral extinctions increased dramatically during certain periods, but whether the processes affecting extinction rates today are helpful in interpreting extinction in the past and, conversely, whether prehistoric extinctions are useful for understanding recent extinctions is challenged.
Abstract: The fossil record of the earth shows that faunal and floral extinctions increased dramatically during certain periods. These “paleo” upheavals like those at the end of Permian and Cretaceous have long provided the punctuations that geologists and paleontologists use to divide the geological periods. A challenging question in conservation science is whether the processes affecting extinction rates today are helpful in interpreting extinction in the past and, conversely, whether prehistoric extinctions are useful for understanding recent extinctions.
98 citations
References
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Book•
01 Jan 1956
TL;DR: This is the revision of the classic text in the field, adding two new chapters and thoroughly updating all others as discussed by the authors, and the original structure is retained, and the book continues to serve as a combined text/reference.
Abstract: This is the revision of the classic text in the field, adding two new chapters and thoroughly updating all others. The original structure is retained, and the book continues to serve as a combined text/reference.
35,552 citations
TL;DR: Technique non parametrique pour la signification statistique de tables de tests utilisees dans les etudes sur l'evolution notamment.
Abstract: Technique non parametrique pour la signification statistique de tables de tests utilisees dans les etudes sur l'evolution notamment
14,666 citations
Book•
01 Jan 1972
TL;DR: The summation of the life work of one of the most influential scientists of our time is presented in the book "Genius: A Summary of the Life Work of Thomas E. MacArthur" as mentioned in this paper.
Abstract: First published in 1972 and now available for the first time in paperback, this book is the summation of the life work of one of the most influential scientists of our time. Of permanent interest in the history and philosophy of science, it is also frequently cited in the current ecological literature and is still up-to-date in many categories. "The theme running through this book," MacArthur wrote, "is that the structure of the environment, the morphology of the species, the economics of species behavior, and the dynamics of population changes are the four essential ingredients of all interesting biogeographic patterns." Written in his beautifully lucid style, this work will continue to be read by anyone concerned with biological ideas.
2,182 citations
TL;DR: It is suggested that such small, non-dimorphic species are best suited for insinuation into complex faunas, whereas larger, dimorphic forms are best for the colonization of empty areas.
Abstract: The tiny island of South Bimini contains 4 species of lizards of the genus Anolis, a number surpassed only on the 4 largest islands of the Greater Antilles and on 2 very large and nearby satellite islands. These species are syntopic with respect to a two-dimensional area of the ground but divide the habitat according to perch height and perch diameter: sagrei is partly terrestrial, but occurs more often on small and large low perches; distichus prefers the trunks and large branches of medium to large trees; angusticeps inhabits small twigs, especially at great heights; and carolinensis is found mostly on leaves or on the adjacent twigs and branches. The size classes of the species are staggered in such a way that the inter- specific classes which overlap most in habitat overlap least in prey size. Similarities in prey size and prey taxa for classes of the same species are somewhat greater than those expected on the basis of habitat and morphology alone. The distribution of the species among the vegetation communities of Bimini can be explained on the basis of perch height and diameter preference. Within the same species, the larger lizards usually eat larger food, fewer items, and in sagrei more fruit; and they have a greater average range of food size per digestive tract. One species (distichus) is extremely myrmecophagous: about 75-90% of its food items are ants. In 3 of the 4 species, subadult males take more food and average smaller prey than females of the same head length. That species (distichus) which takes the smallest food item; and whose classes overlap the most in habitat preference with those of other species is least dimorphic in size between the sexes. It is suggested that such small, non- dimorphic species are best suited for insinuation into complex faunas, whereas larger, dimorphic forms are best for the colonization of empty areas. The usefulness of various measures of "overlap" and "specialization" is evaluated for this lizard association.
1,737 citations
Book•
01 Jan 1986
TL;DR: This book is the classic account of how much the authors have since learned about the evolution of Darwin's Finches and shows how interspecific competition and natural selection act strongly enough on contemporary populations to produce observable and measurable evolutionary change.
Abstract: After his famous visit to the Galapagos Islands, Darwin speculated that "one might fancy that, from an original paucity of birds in this archipelago, one species had been taken and modified for different ends." This book is the classic account of how much we have since learned about the evolution of these remarkable birds. Based upon over a decade's research, Grant shows how interspecific competition and natural selection act strongly enough on contemporary populations to produce observable and measurable evolutionary change. In this new edition, Grant outlines new discoveries made in the thirteen years since the book's publication. "Ecology and Evolution of Darwin's Finches" is an extraordinary account of evolution in action."
1,144 citations