Medan D./Публикации

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Автор
АВТОР ПУБЛИКАЦИЙ 16
Burgos E.
1
Автор антэкологических публикаций

et al. (+6)
Journal of Theoretical Biology
1
Журнал с антэкологическими публикациями.
Elsevier

. 2007. V. 249. No. 2. P. 307–313. Статья
We investigate the relationship between the nested organization of mutualistic systems and their robustness against the extinction of species. We establish that a nested pattern of contacts is the best possible one as far as robustness is concerned, but only when the least linked species have the greater probability of becoming extinct. We introduce a coefficient that provides a quantitative measure of the robustness of a mutualistic system.
Devoto M.
16
Автор антэкологических публикаций

, Medan D.
16
Автор антэкологических публикаций

Revista Chilena de Historia Natural
Журнал с антэкологическими публикациями.
Sociedad de Biología de Chile

. 2006. V. 79. P. 29–40. Статья
Tangle-veined flies (Nemestrinidae) constitute a primitive and rather widespread family among Diptera. The genus Trichophthalma occurs in Australia and South America and is the only one in the family with a typically Gondwanian, disjoint distribution. The ecology and distribution of most southern South American species of this genus remains virtually unknown. We studied the diversity, distribution and flower specificity of flower-visiting species of the genus Trichophthalma in the temperate fore
sts of southern South America in ten sites along an east-west rainfall gradient (37-40o S) on the eastern slope of the Andes. We recorded nine species of Trichophthalma, which showed an overlapped distribution along the gradient and different degrees of floral specificity. Three species are reported for Argentina for the first time and three are first recorded as flower visitors to the local flora. Our results show that while in southern Africa tangle-veined flies are engaged in highly specialized pollination interactions with long-tubed species, the Trichophthalma spp. of Patagonia share their flowers with a diverse and rather unspecialized visitor fauna among which several species of flies, bees and birds are present.
Roitman G.G.
2
Автор антэкологических публикаций

, Montaldo N.H.
5
Автор антэкологических публикаций

, Medan D.
16
Автор антэкологических публикаций

Biotropica
8
Журнал с антэкологическими публикациями.
Wiley-Blackwell

. 1997. V. 29. No. 2. P. 162–168. Статья
Myrrhinium atropurpureurn has unusual floral characteristics: sweet, juicy petals, long vivid stamens, and absence of nectar and odor. This uncommon syndrome is morphologically and anatomically described. Floral phenology is also described, and censuses of flower visitors are provided. The main pollinators are frugivorous passerine birds, which are attracted by the petals. This type of floral reward is vev uncommon and seems to be restricted, in South America, to Myrrhinium, &&a (Myrtaceae) and
Calreohria (Scrophulariaceae). The possible origin of the pollination mechanism is discussed.
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Medan D.
16
Автор антэкологических публикаций

, Bartoloni N.
1
Автор антэкологических публикаций

Annals of Botany
513
Журнал с антэкологическими публикациями.
Oxford University Press · office@annbot.com

. 2000. V. 85. No. 2. P. 167–180. Статья
Presentation of pollen and stigmas at different times by individuals of a population is likely to exert a profound influence on its genetic structure. We have analysed the changes undergone in (1) asynchrony and (2) single locus heterozygosity, under the irruption of self-incompatible variants in a population of random-mating hermaphroditic annuals. Equations relating genotypic frequencies with time-dependent gamete availability parameters were obtained. These were run in a numerical example ove
r 20 generations, starting from a mixed population showing different degrees of asynchrony depending on the mode of inheritance of this trait. Five cases were analysed, differing in the degree of dominance. Self-incompatibility starts to be expressed in the first generation. Dominance for early- and late-flowering times was negatively associated with asynchrony, due to the existence of self-incompatible variants. A higher degree of potential genetic variability was observed in the locus controlling pollen availability than in the one controlling ovules in advanced generations under this reproductive system.
Devoto M.
16
Автор антэкологических публикаций

, Medan D.
16
Автор антэкологических публикаций

Ecología Aplicada
1
Журнал с антэкологическими публикациями.

. 2004. V. 3. No. 1, 2. P. 188–191. Статья
We present preliminary evidence for the existence of a genetic landscape-level structuring that might be a consequence of depressed pollen flow across heavily grazed populations of Cypella herbertii.
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Devoto M.
16
Автор антэкологических публикаций

, Medan D.
16
Автор антэкологических публикаций

, Montaldo N.H.
5
Автор антэкологических публикаций

Oikos
29
Журнал с антэкологическими публикациями.
Wiley-Blackwell on behalf of the Nordic Foundation Oikos

. 2005. V. 109. P. 461–472. Статья
Patterns of variation in plant /pollinator (p /p) systems in response to environmental variables have been the focus of much recent attention. We analyzed species diversity and generalization of interactions of flower visitors belonging to eight p /p networks along a steep rainfall gradient in NW Patagonia, Argentina. To our knowledge, this is the first published study that applies a humidity / gradient approach to p /p networks analysis. Throughout the gradient, we recorded 1232 interactions b
etween 413 different animal species and 111 plant species. We found that (a) specialization measures showed no clear pattern of variation throughout the rainfall gradient, (b) the diversity of flower-visiting insects does not consistently respond to rainfall gradients along the gradient, and (c) as we predicted, flies dominated the wetter end of the gradient, while at the drier end bees prevailed. The lack of differences in diversity could be explained by the repeated cycles of species extinctions undergone in the past by the southern temperate forests, which dominate the wetter end of the gradient. A logistic model that related the flies’ dominance of the visitor assemblage with latitude was good predictor of the average fly composition of the entire region, although we found major betweensite variations in response to local environmental conditions. The replacement of flies by bees towards the drier end of the gradient seemed to repeat a worldwide pattern where flies dominate humid regions while bees attain their greatest abundance in xeric regions. Regional patterns in the structure of our p /p systems (composition of the visitor fauna) were better explained by altitudinal differences, while function (percentage of interactions established by each taxon) seemed to be more influenced by precipitation.
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Devoto M.
16
Автор антэкологических публикаций

, Medan D.
16
Автор антэкологических публикаций

Plant Systematics and Evolution
49
Журнал с антэкологическими публикациями.
Springer Science+Business Media

. 2004. V. 243. No. 3. P. 165–173. Статья
A recent study in a natural grassland in Argentina revealed that grazing strongly reduced the available pollinators for a population of Cypella herbertii. Comparing grazed and fenced areas (exclosures) we tested the hypothesis that self-incompatibility would be selected against in a pollinator-poor environment leading to changes in breeding system. No differences in breeding system were found between populations from inside and outside exclosures. However, we detected: (i) C. herbertii clearly e
xhibits a mixed-mating system but has a remarkably low spontaneous fruit formation; (ii) this species though highly self-compatible expresses a significant decay at seed set stage when self-pollinated. We conclude that grazing impact on pollinators together with C. herbertii’s high dependence on pollinators should be considered when assessing the risk of extinction of this species.
Devoto M.
16
Автор антэкологических публикаций

, Medan D.
16
Автор антэкологических публикаций

Acta Botánica Venezuélica
Журнал с антэкологическими публикациями.
Instituto Experimental Jardín Botánico "Dr. Tobías Lasser"

. 2008. V. 31. No. 2. P. 425–434. Статья
Iridaceae is an interesting plant family from the viewpoint of reproductive biology because the diverse floral structures of its species attract a gamut of different flower visitors. This work reports some reproductive aspects of five species of Iridaceae of the Salado river basin in the Argentine pampas: Cypella herbertii, Alophia lahue and three species of Sisyrinchium. C. herbertii exhibits a specialized interaction with oil-collecting bees, while the rest of the species studied had rather un
specialized visitors. For A. lahue and the species of Sisyrinchium analyzed estimations of expected mating system tend to underestimate the degree of autogamy found in previous experiments. Field observations verified the production of nectar in the flowers of C. herbertii and suggested that the reproductive success of this species might be pollen limited in one of the population studied.
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Devoto M.
16
Автор антэкологических публикаций

et al. (+3)
Austral Ecology
Журнал с антэкологическими публикациями.
Blackwell Science Asia

. 2009. V. 34. P. 848–857. Статья
Recent studies have assessed the influence of different types of gradients (e.g. altitudinal, latitudinal and temporal, among others) on the structure and function of community-level plant-pollinator webs. Although the importance of humidity as a major driver of species-richness gradients worldwide has been stressed by recent reviews, no studies have been specifically designed to address the influence of precipitation gradients on pollination webs. In the present paper we describe for the first
time the turnover of species of plants and their associated flower visitors between eight communities located along a steep precipitation gradient in north-west Patagonia, Argentina. Our results show that: (i) there is a high spatial turnover of plant communities and their associated pollinators; (ii) this turnover is strongly related to precipitation changes across the region; and (iii) the turnover rate is similar for plants and pollinators. Our results support the view that the precipitation gradient is a significant factor associated with the regional turnover of plants and their pollinators in the temperate forests of southern South America.
Devoto M.
16
Автор антэкологических публикаций

, Zimmermann M.
2
Автор антэкологических публикаций

, Medan D.
16
Автор антэкологических публикаций

Ecologia Austral
1
Журнал с антэкологическими публикациями.
Asociacion Argentina de Ecologia

. 2007. V. 17. No. 1. P. 37–50. Статья
Climate change threatens the integrity of pollination webs by decoupling plants and flower visitors both phenologically and ecologically. We simulated a range shift of flower-visitor species along a steep east-west rainfall gradient to explore resulting patterns of extinction. The systems studied seemed to be rather robust to range shifts. This results from (a) the positive correlation between the geographic range and both the local (i.e. at each site) and the regional (i.e. pooling across sites
) number of interaction partners of the plants and flower visitors of these webs, and (b) a nested assembly of interactions at the regional level. In a broader context, this study reveals itself as a useful tool for understanding the links between the interaction pattern of mutualistic webs and their response to a major threat such as climate change.
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Medan D.
16
Автор антэкологических публикаций

, Castillo-Campos G.
1
Автор антэкологических публикаций

, Zarlavsky G.
1
Автор антэкологических публикаций

Journal of Pollination Ecology
123
Журнал с антэкологическими публикациями.

. 2015. V. 16. P. –. Статья
The reproduction of the shrub Adolphia infesta was studied in a population included in a Mexican agricultural landscape with small, cultivated plots and fragments of natural habitat. Adolphia infesta had reproductive traits consistent with those known for its tribe Colletieae, including small zoophilous flowers exposed to both xenogamous, geitonogamous and visitor-facilitated intrafloral pollination, with selfing being at least partially hindered by self-incompatibility. Visual and olfactory cue
s, together with easily accessible rewards (nectar and pollen), explain the diversity (68 species of 29 families) of insects attracted to the flowers. However, only a small subset can be considered potential pollinators (honeybee and three muscoid flies). In late floral development, pedicel bending brings the developing fruit to an upright position, which might later optimise explosive seed dispersal. The finding of this trait in A. infesta makes fruit erection a synapomorphy of the Adolphia – Discaria – Kentrothamnus clade of the tribe Colletieae. At the study site, A. infesta played a significant role as food source for the local anthophilous insect community, and through its flower visitors, the plant was indirectly connected to 11 other plant species. Knowledge derived from community studies should be applied in conservation initiatives directed at enhancing farmers’ appreciation of extant local biodiversity.
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Devoto M.
16
Автор антэкологических публикаций

, Montaldo N.H.
5
Автор антэкологических публикаций

, Medan D.
16
Автор антэкологических публикаций

Austral Ecology
Журнал с антэкологическими публикациями.
Blackwell Science Asia

. 2006. V. 31. P. 512–519. Статья
The pollination ecology of eight populations of the tree Embothrium coccineum was studied along a steep rainfall gradient in NW Patagonia, Argentina. The showy red flowers suggest an ornithophilous pollination syndrome and they have been reported to attract hummingbirds in Argentina and hummingbirds and passerines in Chile. At each population, flower visitors were recorded and floral rewards were analysed. We found a highly significant increase in nectar concentration towards the drier end of th
e gradient, but this change was not related to the turnover of species in the flower-visitor assemblage of E. coccineum. In addition to the hummingbird Sephanoides sephaniodes (Green-Backed Firecrown, Trochilidae) which is widespread throughout the temperate forest at this latitude, other species seem to be locally important as pollinators of E. coccineum in some sites in Argentina (e.g. two long-tongued tanglewing flies (Nemestrinidae) of the genus Trichophthalma). The long-dated occurrence of tanglewing flies in South America, relative to the more modern hummingbirds, suggests that ornithophily may be a derived character in E. coccineum, the ancestral condition being pollination by Nemestrinidae
Medan D.
16
Автор антэкологических публикаций

, Devoto M.
16
Автор антэкологических публикаций

Plant Systematics and Evolution
49
Журнал с антэкологическими публикациями.
Springer Science+Business Media

. 2005. V. 254. No. 3-4. P. 173–184. Статья
We surveyed four populations of contrasting size (two isolated and two large stands) of a woody outcrossing species, Discaria trinervis (Rhamnaceae), which has a naturally dissected distribution. Our main goal was to investigate the floral biology, breeding system and pollination mechanism of the species, which in turn may help to explain the mechanisms underlying the survival of the isolated populations. Discaria trinervis is both wind- and insect-pollinated, showing interactions with a large f
raction of the available flower visitors at both stand sizes. In the larger populations, stigmatic loads were larger, more pollen tubes reached the ovules, and fruit and seed set were higher; however, the reproductive output in the smaller populations (over 2000 seeds per plant per year) seemed adequate for population persistence. Human disturbance (e.g. destruction of trees for wood extraction) may put these smaller populations at risk through loss of incompatibility alleles. The results suggest that plant species with naturally dissected distributions may provide clues about which reproductive mechanisms ensure survival under fragmentation.
Medan D. et al. (+5)
В книге: Plant–pollinator interactions: from specialization to generalization / Editors: Waser N.M., Ollerton J. Chicago: The University of Chicago Press, 2006. 488 pp. AID: 5454444785. Book P. 245–259. AID: 3264209632. Часть книги
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Medan D.
16
Автор антэкологических публикаций

et al. (+6)
. 2002. V. 34. No. 3. P. 233–241. Статья
The assemblages of visitors to angiosperms flowering at a montane and at a high alpine site in the Andes of Mendoza, Argentina (33-34?S) were described and the plant-flower visitor matrices were analyzed and compared to other systems, in particular those located at a similar latitude on the western slope of the Andes. In the low-altitude (montane) habitat, 23 plant species had a total of 126 interactions with 71 taxa of insects and one hummingbird, and at the higher site 21 plants and 45 insect
species had 83 interactions. Connectances of the visitor matrices were 7.6 and 8.7, respectively. Diptera and Hymenoptera dominated the visitor assemblages at both sites without change of proportions with altitude, while Lepidoptera significantly increased at the higher site. Flies were more species-rich than expected at the sites' latitude and more constant across altitudes than is usually observed. Lack of a significant decrease with altitude of (1) the frequency of Hymenoptera and (2) the number of interactions per plant were the main differences with a comparable gradient in the Chilean Andes. The proportion of self-compatible species increased with altitude; however, use of phylogenetically-independent contrasts showed that the prevalence of selfers at higher altitudes does not reflect a generalized reaction pattern but results from two speciose families (Asteraceae and Fabaceae) showing more self-compatibility at high altitudes.
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Medan D.
16
Автор антэкологических публикаций

, Devoto M.
16
Автор антэкологических публикаций

Revista del Museo Argentino de Ciencias Naturales
1
Журнал с антэкологическими публикациями.
Museo Argentino de Ciencias Naturales

. 2008. V. 10. No. 1. P. 155–160. Статья
The genus Trichophthalma (Diptera: Nemestrinidae) was last revised for Argentina in 1939. Since then several species were newly cited or described for this country but no comprehensive treatment of the genus was published. The analysis of our own extensive collections and of the holdings of Trichophthalma at three major entomological collections in Argentina showed that eleven different species of Trichophthalma exist in this coun-try, and that three of these have an unexpectedly ample distribut
ion, including areas unconnected to the southern temperate forests of Patagonia, where all previous records were concentrated. A key for all Argentinean species is provided.