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Thaís B. Guedes - One of the best experts on this subject based on the ideXlab platform.
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Diversity, natural history, and geographic distribution of snakes in the Caatinga, Northeastern Brazil.
Zootaxa, 2014Co-Authors: Thaís B. Guedes, Cristiano Nogueira, Otavio Augusto Vuolo MarquesAbstract:The present study is a synthesis on snake diversity and distribution in the Caatinga region of northeastern Brazil, providing an updated species list and data on natural history and geographic distribution. Our study is based on the careful revision of 7,102 voucher specimens, housed in 17 herpetological collections, complemented by data on taxonomic literature. We recorded a total of 112 snake species in the Caatinga, belonging to nine families: Anomalepididae, Leptotyphlopidae, Typhlopidae, Aniliidae, Boidae, Viperidae, Elapidae, Colubridae, and Dipsadidae. Our list includes at least 13 never recorded species for this region, as well as distribution records for all species known from the Caatinga (including expansion and new records of distribution). The snake assemblage of the Caatinga is complex, sharing species with other continental open areas (38.4%), forested areas (27.7%), and both open and forested areas (32.1%). The richest areas were isolated plateaus, followed by contact areas, semi-arid Caatinga, and sandy dunes of the Sao Franscisco River. We identified 22 Caatinga endemic species with the sandy dunes of Sao Franscico River showing the highest endemism level (12 species, with six endemic species restricted to the area) followed by semi-arid Caatinga, and isolated plateaus (eight endemic species each, and six and three endemic species with restricted distribution to each area, respectively). Most species show relatively restricted ranges in parts of the Caatinga. The snake assemblage in Caatinga includes mainly terrestrial species (38.4%), followed by fossorial/cryptozoic (26.8%), arboreal/semi-arboreal (26.8%), and aquatic/semi-aquatic (7.1%) species. Vertebrates are the most important dietary item (80.4%), with 56.6% of species being generalist consumers of this kind of prey; 24.4% are frog-eaters, 7.8% prey on caecilians/amphisbaenians, 6.7% lizard-eaters, 3.3% mammal-eaters, and 1.1% are fish-eaters. Only 18.7% of the snakes eat invertebrate prey, as arthropods, annelids, and mollusks. In relation to time of activity, 35.7% of snakes are both diurnal and nocturnal, 33.0% are strictly nocturnal, and 30.4% are diurnal. The data provided herein increase the list of Caatinga snake species from 50 to 112, and includes detailed maps and information on geographic distribution. The Caatinga snake assemblage shows high richness and endemism levels, and our results highlight the usefulness of basic natural history data and revision of voucher specimens as baseline information for biogeographic studies and conservation strategies.
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biogeography vicariance and conservation of snakes of the neglected and endangered Caatinga region north eastern brazil
Journal of Biogeography, 2014Co-Authors: Ricardo J Sawaya, Thaís B. Guedes, Cristiano NogueiraAbstract:Aim Our aims were to test the predictions of the vicariance model, searching for natural, non-random biogeographical units using data on snake distributions, and to assess the conservation of biogeographical patterns and underlying processes in the poorly studied Caatinga region. Location Caatinga region, north-eastern Brazil. Methods We revised and georeferenced 7352 snake occurrence records at point localities, by direct examination of voucher specimens in zoological collections and revision of literature data. We tested two predictions of the vicariance model via biotic element analysis using two datasets (all taxa and endemics) mapped onto a 1° × 1° square grid across the Caatinga. Finally, we examined the overlap between recovered biogeographical units and spatial patterns of habitat loss and protected area coverage. Results We recorded 112 snake species from the Caatinga, of which 22 (20%) are endemics. The predictions of the vicariance model were corroborated by the detection of groups of species with significantly clustered ranges (biotic elements). The analysis with the full dataset detected eight biotic elements, and three endemic biotic elements were found when only using endemics. The three endemic biotic elements correspond to core areas of biotic elements detected with the larger dataset. The average habitat loss for species forming biotic elements was 46%, and was similar among biotic elements. Protected area coverage is different for species from different biotic elements, and most species' ranges are very poorly represented in protected areas. Main conclusions The Caatinga harbours a peculiar snake fauna with significantly clustered species ranges concordant with the predictions of the vicariance model. Our results, representing the first formal test of vicariance patterns in the Caatinga, detected poor overlap between biotic elements and protected areas, indicating that biogeographical patterns and processes are largely unprotected in this imperilled and neglected Neotropical region.
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Biogeography, vicariance and conservation of snakes of the neglected and endangered Caatinga region, north‐eastern Brazil
Journal of Biogeography, 2014Co-Authors: Thaís B. Guedes, Ricardo J Sawaya, Cristiano NogueiraAbstract:Aim Our aims were to test the predictions of the vicariance model, searching for natural, non-random biogeographical units using data on snake distributions, and to assess the conservation of biogeographical patterns and underlying processes in the poorly studied Caatinga region. Location Caatinga region, north-eastern Brazil. Methods We revised and georeferenced 7352 snake occurrence records at point localities, by direct examination of voucher specimens in zoological collections and revision of literature data. We tested two predictions of the vicariance model via biotic element analysis using two datasets (all taxa and endemics) mapped onto a 1° × 1° square grid across the Caatinga. Finally, we examined the overlap between recovered biogeographical units and spatial patterns of habitat loss and protected area coverage. Results We recorded 112 snake species from the Caatinga, of which 22 (20%) are endemics. The predictions of the vicariance model were corroborated by the detection of groups of species with significantly clustered ranges (biotic elements). The analysis with the full dataset detected eight biotic elements, and three endemic biotic elements were found when only using endemics. The three endemic biotic elements correspond to core areas of biotic elements detected with the larger dataset. The average habitat loss for species forming biotic elements was 46%, and was similar among biotic elements. Protected area coverage is different for species from different biotic elements, and most species' ranges are very poorly represented in protected areas. Main conclusions The Caatinga harbours a peculiar snake fauna with significantly clustered species ranges concordant with the predictions of the vicariance model. Our results, representing the first formal test of vicariance patterns in the Caatinga, detected poor overlap between biotic elements and protected areas, indicating that biogeographical patterns and processes are largely unprotected in this imperilled and neglected Neotropical region.
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Figure 12 In Diversity, Natural History, And Geographic Distribution Of Snakes In The Caatinga, Northeastern Brazil
2014Co-Authors: Thaís B. Guedes, Cristiano Nogueira, Otavio Augusto Vuolo MarquesAbstract:FIGURE 19. Snakes recorded in the Caatinga region. Photos with * were obtained from specimens collected and photographed in the Caatinga region. 19.1. Siphlophis leucocephalus *, photo by Rodrigo Souza; 19.2. Taeniophallus affinis; 19.3. Taeniophallus occipitalis; 19.4. Thamnodynastes almae *, photo by Marcelo Duarte; 19.5. Thamnodynastes hypoconia; 19.6. Thamnodynastes pallidus *, photo by Breno Hamdan; 19.7. Thamnodynastes sertanejo *, photo by Silvaney Medeiros; 19.8. Thamnodynastes sp. *.
Juan Gregorio Rejas Ayuga - One of the best experts on this subject based on the ideXlab platform.
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assessment of Caatinga response to drought using meteosat seviri normalized difference vegetation index 2008 2016
Isprs Journal of Photogrammetry and Remote Sensing, 2019Co-Authors: Humberto Alves Barbosa, Franklin Paredes, Simon Elliott, T Lakshmi V Kumar, Juan Gregorio Rejas AyugaAbstract:Abstract The Caatinga semi-arid vegetation in Northeast region of Brazil (NEB) provides a unique opportunity for studying the vegetation in response to recurring droughts, because of its negative impacts on soil erosion. Surprisingly, however, the response of Caatinga vegetation to a recent multi-year drought across the entire semi-arid NEB has not been studied in detail. This study analyses the spatiotemporal patterns of drought impact on the Caatinga vegetation between 2008 and 2016. Yet previous research has shown that a linear relationship exists between rainfall and Caatinga vegetation at interannual timescale. Because of the strong large-scale control of precipitation, year-to-year rainfall variations have a notable degree of spatiotemporal heterogeneity in semi-arid NEB. We exploit this relationship by developing the local-to regional-scale rainfall-Normalized Difference Vegetation Index (NDVI) distribution over the Caatinga vegetation, using daily rainfall time series from in situ weather stations, and daily Meteosat Second Generation (MSG) NDVI time series. Results showed that the drought impact (2012–2015) through the rainfall deficit dynamics influenced the dynamics of vegetative drought in the Caatinga vegetation where exhibit a strong decrease in vegetation activity, contrasting with irrigated croplands that exhibit little sensitivity to drought. It is the longest, continuous drought on the historical record (1901 onwards). The severe drought year of 2012 affected more than 26% of the vegetated area in the region. Over the 2012–2016 period, the positive trend observed in vegetation greenness is largely explained by a positive trend in the rainfall over 45% of the Caatinga vegetation, with the three months lagged rainfall (R2 = 0.62 with p
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Assessment of Caatinga response to drought using Meteosat-SEVIRI Normalized Difference Vegetation Index (2008–2016)
ISPRS Journal of Photogrammetry and Remote Sensing, 2019Co-Authors: Humberto Alves Barbosa, T. V. Lakshmi Kumar, Franklin Paredes, Simon Elliott, Juan Gregorio Rejas AyugaAbstract:Abstract The Caatinga semi-arid vegetation in Northeast region of Brazil (NEB) provides a unique opportunity for studying the vegetation in response to recurring droughts, because of its negative impacts on soil erosion. Surprisingly, however, the response of Caatinga vegetation to a recent multi-year drought across the entire semi-arid NEB has not been studied in detail. This study analyses the spatiotemporal patterns of drought impact on the Caatinga vegetation between 2008 and 2016. Yet previous research has shown that a linear relationship exists between rainfall and Caatinga vegetation at interannual timescale. Because of the strong large-scale control of precipitation, year-to-year rainfall variations have a notable degree of spatiotemporal heterogeneity in semi-arid NEB. We exploit this relationship by developing the local-to regional-scale rainfall-Normalized Difference Vegetation Index (NDVI) distribution over the Caatinga vegetation, using daily rainfall time series from in situ weather stations, and daily Meteosat Second Generation (MSG) NDVI time series. Results showed that the drought impact (2012–2015) through the rainfall deficit dynamics influenced the dynamics of vegetative drought in the Caatinga vegetation where exhibit a strong decrease in vegetation activity, contrasting with irrigated croplands that exhibit little sensitivity to drought. It is the longest, continuous drought on the historical record (1901 onwards). The severe drought year of 2012 affected more than 26% of the vegetated area in the region. Over the 2012–2016 period, the positive trend observed in vegetation greenness is largely explained by a positive trend in the rainfall over 45% of the Caatinga vegetation, with the three months lagged rainfall (R2 = 0.62 with p
Cristiano Nogueira - One of the best experts on this subject based on the ideXlab platform.
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Diversity, natural history, and geographic distribution of snakes in the Caatinga, Northeastern Brazil.
Zootaxa, 2014Co-Authors: Thaís B. Guedes, Cristiano Nogueira, Otavio Augusto Vuolo MarquesAbstract:The present study is a synthesis on snake diversity and distribution in the Caatinga region of northeastern Brazil, providing an updated species list and data on natural history and geographic distribution. Our study is based on the careful revision of 7,102 voucher specimens, housed in 17 herpetological collections, complemented by data on taxonomic literature. We recorded a total of 112 snake species in the Caatinga, belonging to nine families: Anomalepididae, Leptotyphlopidae, Typhlopidae, Aniliidae, Boidae, Viperidae, Elapidae, Colubridae, and Dipsadidae. Our list includes at least 13 never recorded species for this region, as well as distribution records for all species known from the Caatinga (including expansion and new records of distribution). The snake assemblage of the Caatinga is complex, sharing species with other continental open areas (38.4%), forested areas (27.7%), and both open and forested areas (32.1%). The richest areas were isolated plateaus, followed by contact areas, semi-arid Caatinga, and sandy dunes of the Sao Franscisco River. We identified 22 Caatinga endemic species with the sandy dunes of Sao Franscico River showing the highest endemism level (12 species, with six endemic species restricted to the area) followed by semi-arid Caatinga, and isolated plateaus (eight endemic species each, and six and three endemic species with restricted distribution to each area, respectively). Most species show relatively restricted ranges in parts of the Caatinga. The snake assemblage in Caatinga includes mainly terrestrial species (38.4%), followed by fossorial/cryptozoic (26.8%), arboreal/semi-arboreal (26.8%), and aquatic/semi-aquatic (7.1%) species. Vertebrates are the most important dietary item (80.4%), with 56.6% of species being generalist consumers of this kind of prey; 24.4% are frog-eaters, 7.8% prey on caecilians/amphisbaenians, 6.7% lizard-eaters, 3.3% mammal-eaters, and 1.1% are fish-eaters. Only 18.7% of the snakes eat invertebrate prey, as arthropods, annelids, and mollusks. In relation to time of activity, 35.7% of snakes are both diurnal and nocturnal, 33.0% are strictly nocturnal, and 30.4% are diurnal. The data provided herein increase the list of Caatinga snake species from 50 to 112, and includes detailed maps and information on geographic distribution. The Caatinga snake assemblage shows high richness and endemism levels, and our results highlight the usefulness of basic natural history data and revision of voucher specimens as baseline information for biogeographic studies and conservation strategies.
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biogeography vicariance and conservation of snakes of the neglected and endangered Caatinga region north eastern brazil
Journal of Biogeography, 2014Co-Authors: Ricardo J Sawaya, Thaís B. Guedes, Cristiano NogueiraAbstract:Aim Our aims were to test the predictions of the vicariance model, searching for natural, non-random biogeographical units using data on snake distributions, and to assess the conservation of biogeographical patterns and underlying processes in the poorly studied Caatinga region. Location Caatinga region, north-eastern Brazil. Methods We revised and georeferenced 7352 snake occurrence records at point localities, by direct examination of voucher specimens in zoological collections and revision of literature data. We tested two predictions of the vicariance model via biotic element analysis using two datasets (all taxa and endemics) mapped onto a 1° × 1° square grid across the Caatinga. Finally, we examined the overlap between recovered biogeographical units and spatial patterns of habitat loss and protected area coverage. Results We recorded 112 snake species from the Caatinga, of which 22 (20%) are endemics. The predictions of the vicariance model were corroborated by the detection of groups of species with significantly clustered ranges (biotic elements). The analysis with the full dataset detected eight biotic elements, and three endemic biotic elements were found when only using endemics. The three endemic biotic elements correspond to core areas of biotic elements detected with the larger dataset. The average habitat loss for species forming biotic elements was 46%, and was similar among biotic elements. Protected area coverage is different for species from different biotic elements, and most species' ranges are very poorly represented in protected areas. Main conclusions The Caatinga harbours a peculiar snake fauna with significantly clustered species ranges concordant with the predictions of the vicariance model. Our results, representing the first formal test of vicariance patterns in the Caatinga, detected poor overlap between biotic elements and protected areas, indicating that biogeographical patterns and processes are largely unprotected in this imperilled and neglected Neotropical region.
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Biogeography, vicariance and conservation of snakes of the neglected and endangered Caatinga region, north‐eastern Brazil
Journal of Biogeography, 2014Co-Authors: Thaís B. Guedes, Ricardo J Sawaya, Cristiano NogueiraAbstract:Aim Our aims were to test the predictions of the vicariance model, searching for natural, non-random biogeographical units using data on snake distributions, and to assess the conservation of biogeographical patterns and underlying processes in the poorly studied Caatinga region. Location Caatinga region, north-eastern Brazil. Methods We revised and georeferenced 7352 snake occurrence records at point localities, by direct examination of voucher specimens in zoological collections and revision of literature data. We tested two predictions of the vicariance model via biotic element analysis using two datasets (all taxa and endemics) mapped onto a 1° × 1° square grid across the Caatinga. Finally, we examined the overlap between recovered biogeographical units and spatial patterns of habitat loss and protected area coverage. Results We recorded 112 snake species from the Caatinga, of which 22 (20%) are endemics. The predictions of the vicariance model were corroborated by the detection of groups of species with significantly clustered ranges (biotic elements). The analysis with the full dataset detected eight biotic elements, and three endemic biotic elements were found when only using endemics. The three endemic biotic elements correspond to core areas of biotic elements detected with the larger dataset. The average habitat loss for species forming biotic elements was 46%, and was similar among biotic elements. Protected area coverage is different for species from different biotic elements, and most species' ranges are very poorly represented in protected areas. Main conclusions The Caatinga harbours a peculiar snake fauna with significantly clustered species ranges concordant with the predictions of the vicariance model. Our results, representing the first formal test of vicariance patterns in the Caatinga, detected poor overlap between biotic elements and protected areas, indicating that biogeographical patterns and processes are largely unprotected in this imperilled and neglected Neotropical region.
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Figure 12 In Diversity, Natural History, And Geographic Distribution Of Snakes In The Caatinga, Northeastern Brazil
2014Co-Authors: Thaís B. Guedes, Cristiano Nogueira, Otavio Augusto Vuolo MarquesAbstract:FIGURE 19. Snakes recorded in the Caatinga region. Photos with * were obtained from specimens collected and photographed in the Caatinga region. 19.1. Siphlophis leucocephalus *, photo by Rodrigo Souza; 19.2. Taeniophallus affinis; 19.3. Taeniophallus occipitalis; 19.4. Thamnodynastes almae *, photo by Marcelo Duarte; 19.5. Thamnodynastes hypoconia; 19.6. Thamnodynastes pallidus *, photo by Breno Hamdan; 19.7. Thamnodynastes sertanejo *, photo by Silvaney Medeiros; 19.8. Thamnodynastes sp. *.
Marlies Sazima - One of the best experts on this subject based on the ideXlab platform.
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plant sexual systems and a review of the breeding system studies in the Caatinga a brazilian tropical dry forest
Annals of Botany, 2006Co-Authors: Isabel Cristina Machado, Ariadna Valentina Lopes, Marlies SazimaAbstract:• Backgrounds and Aims The reproductive biology of a community can provide answers to questions related to the maintenance of the intraspecific pollen flow and reproductive success of populations, sharing and competition for pollinators and also questions on conservation of natural habitats affected by fragmentation processes. This work presents, for the first time, data on the occurrence and frequency of plant sexual systems for Caatinga communities, and a review of the breeding system studies of Caatinga species. • Methods The sexual systems of 147 species from 34 families and 91 genera occurring in three Caatinga areas in north-eastern Brazil were analysed and compared with worldwide studies focusing on reproductive biology of different tropical communities. • Key Results The frequency of hermaphrodite species was 83·0 % (122 species), seven of these (or 4·8 % of the total) being heterostylous. Monoecy occurred in 9·5 % (14) of the species, and andromonoecy in 4·8 % (seven). Only 2·7 % (four) of the species were dioecious. A high percentage of hermaphrodite species was expected and has been reported for other tropical ecosystems. With respect to the breeding system studies with species of the Caatinga, the authors' data for 21 species and an additional 18 species studied by others (n = 39) revealed a high percentage (61·5 %) of obligatory self-incompatibility. Agamospermy was not recorded among the Caatinga studied species. • Conclusions The plant sexual systems in the Caatinga, despite the semi-arid climate, are similar to other tropical dry and wet forest communities, including those with high rainfall levels, except for the much lower percentage of dioecious species. The high frequency of self-incompatible species is similar to that reported for Savanna areas in Brazil, and also for dry (deciduous and semideciduous) and humid tropical forest communities.
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Plant sexual systems and a review of the breeding system studies in the Caatinga, a Brazilian tropical dry forest.
Annals of botany, 2005Co-Authors: Isabel Cristina Machado, Ariadna Valentina Lopes, Marlies SazimaAbstract:The reproductive biology of a community can provide answers to questions related to the maintenance of the intraspecific pollen flow and reproductive success of populations, sharing and competition for pollinators and also questions on conservation of natural habitats affected by fragmentation processes. This work presents, for the first time, data on the occurrence and frequency of plant sexual systems for Caatinga communities, and a review of the breeding system studies of Caatinga species. The sexual systems of 147 species from 34 families and 91 genera occurring in three Caatinga areas in north-eastern Brazil were analysed and compared with worldwide studies focusing on reproductive biology of different tropical communities. The frequency of hermaphrodite species was 83.0 % (122 species), seven of these (or 4.8 % of the total) being heterostylous. Monoecy occurred in 9.5 % (14) of the species, and andromonoecy in 4.8 % (seven). Only 2.7 % (four) of the species were dioecious. A high percentage of hermaphrodite species was expected and has been reported for other tropical ecosystems. With respect to the breeding system studies with species of the Caatinga, the authors' data for 21 species and an additional 18 species studied by others (n = 39) revealed a high percentage (61.5 %) of obligatory self-incompatibility. Agamospermy was not recorded among the Caatinga studied species. The plant sexual systems in the Caatinga, despite the semi-arid climate, are similar to other tropical dry and wet forest communities, including those with high rainfall levels, except for the much lower percentage of dioecious species. The high frequency of self-incompatible species is similar to that reported for Savanna areas in Brazil, and also for dry (deciduous and semideciduous) and humid tropical forest communities.
Ariadna Valentina Lopes - One of the best experts on this subject based on the ideXlab platform.
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The alien flora of Brazilian Caatinga: deliberate introductions expand the contingent of potential invaders
Biological Invasions, 2014Co-Authors: Walkiria R. Almeida, Ariadna Valentina Lopes, Marcelo Tabarelli, Inara R LealAbstract:Alien floras have been examined at regional and continental scales, but the connections between the cause of introduction and the nature and invasiveness of alien floras remain poorly explored. This is despite the fact that initial introduction determines the alien species pool from which the invasion proceeds. Here we examine the profile of the alien flora of the Brazilian Caatinga, a semi-arid tropical vegetation, in order to define the major connections between economic activities, introduction pressure and nature of the alien flora in terms of taxonomy, native ranges and economic use. Alien plant species introduced in the Caatinga ecosystem were compiled from the literature as well as from herbaria surveys. A total of 205 alien plants species were recorded, distributed across 135 genera and 48 families. The alien flora of the Caatinga ecosystem is clearly explained in terms of taxonomy, native ranges and use by human populations. The highest numbers of alien species belong to the families Poaceae (61 spp.) and Fabaceae (33). Nearly one-third of the alien flora is represented by tropical forage plants, particularly grasses from Africa and America, which were introduced deliberately, particularly as forage for grazing livestock. Finally, 20 alien species were considered invasive, nine of them deliberately introduced, such as those species serving as forage for livestock. The Caatinga “case” calls attention to the socio-ecological drivers of alien floras and to which extent particular regions or biotas are susceptible to experiencing further biological invasion due to deliberate introductions.
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Dioecy in the Caatinga, a Brazilian tropical dry forest: typical reproductive traits of a low frequent sexual system
Plant Systematics and Evolution, 2013Co-Authors: Sheila Milena Soares, Isabel Cristina Machado, Antônio Venceslau Aguiar, Ariadna Valentina LopesAbstract:Dioecy is a rare sexual system among angiosperms whose occurrence and frequency depend on the kind and geographical location of the ecosystem. We evaluate the frequency of dioecy in the Caatinga, a special semi-arid vegetation type in Brazil. We compare the floral traits and other ecological characteristics usually related to dioecy between the Caatinga and other tropical ecosystems. Dioecious species of the Caatinga were compiled based on 24 published floristic lists including most of the Caatinga domain. These lists were compared with publications comprising data on sexual systems in different kinds of vegetation in the world. Sexual system confirmation and the database of the reproductive traits of the dioecious species were made by consulting herbaria, literature, and field observations. We registered 22 dioecious species occurring in the Caatinga. The overall dioecy frequency was 2.36 %, considering all Caatinga species, and 6.91 % within woody species. Most dioecious species exhibited traits related to this sexual system (e.g., woody habit, greenish inconspicuous flowers, generalistic pollination syndrome, and zoochory). The distribution of dioecy across the Caatinga plant community exhibited a very low level of phylogenetic signal (D = −0.145), indicating a phylogenetic structure under Brownian evolution (p = 0.671). The frequency of dioecy in the Caatinga (2.36 %) proved lower than reported for angiosperms in general (ca. 6 %) and for other tropical ecosystems. This low frequency can be related to particular ecological characteristics of the Caatinga, such as low percentage of trees >3–4 m tall (13–18.7 %), low rainfall (50 % of the Caatinga vegetation with annual rainfall lower than 750 mm), and strong seasonality (6–9 months of dry season). Dioecious species of the Caatinga exhibited typical reproductive traits for this sexual system, similar to what has been reported for dioecious species of other tropical ecosystems in the world.
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plant sexual systems and a review of the breeding system studies in the Caatinga a brazilian tropical dry forest
Annals of Botany, 2006Co-Authors: Isabel Cristina Machado, Ariadna Valentina Lopes, Marlies SazimaAbstract:• Backgrounds and Aims The reproductive biology of a community can provide answers to questions related to the maintenance of the intraspecific pollen flow and reproductive success of populations, sharing and competition for pollinators and also questions on conservation of natural habitats affected by fragmentation processes. This work presents, for the first time, data on the occurrence and frequency of plant sexual systems for Caatinga communities, and a review of the breeding system studies of Caatinga species. • Methods The sexual systems of 147 species from 34 families and 91 genera occurring in three Caatinga areas in north-eastern Brazil were analysed and compared with worldwide studies focusing on reproductive biology of different tropical communities. • Key Results The frequency of hermaphrodite species was 83·0 % (122 species), seven of these (or 4·8 % of the total) being heterostylous. Monoecy occurred in 9·5 % (14) of the species, and andromonoecy in 4·8 % (seven). Only 2·7 % (four) of the species were dioecious. A high percentage of hermaphrodite species was expected and has been reported for other tropical ecosystems. With respect to the breeding system studies with species of the Caatinga, the authors' data for 21 species and an additional 18 species studied by others (n = 39) revealed a high percentage (61·5 %) of obligatory self-incompatibility. Agamospermy was not recorded among the Caatinga studied species. • Conclusions The plant sexual systems in the Caatinga, despite the semi-arid climate, are similar to other tropical dry and wet forest communities, including those with high rainfall levels, except for the much lower percentage of dioecious species. The high frequency of self-incompatible species is similar to that reported for Savanna areas in Brazil, and also for dry (deciduous and semideciduous) and humid tropical forest communities.
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Plant sexual systems and a review of the breeding system studies in the Caatinga, a Brazilian tropical dry forest.
Annals of botany, 2005Co-Authors: Isabel Cristina Machado, Ariadna Valentina Lopes, Marlies SazimaAbstract:The reproductive biology of a community can provide answers to questions related to the maintenance of the intraspecific pollen flow and reproductive success of populations, sharing and competition for pollinators and also questions on conservation of natural habitats affected by fragmentation processes. This work presents, for the first time, data on the occurrence and frequency of plant sexual systems for Caatinga communities, and a review of the breeding system studies of Caatinga species. The sexual systems of 147 species from 34 families and 91 genera occurring in three Caatinga areas in north-eastern Brazil were analysed and compared with worldwide studies focusing on reproductive biology of different tropical communities. The frequency of hermaphrodite species was 83.0 % (122 species), seven of these (or 4.8 % of the total) being heterostylous. Monoecy occurred in 9.5 % (14) of the species, and andromonoecy in 4.8 % (seven). Only 2.7 % (four) of the species were dioecious. A high percentage of hermaphrodite species was expected and has been reported for other tropical ecosystems. With respect to the breeding system studies with species of the Caatinga, the authors' data for 21 species and an additional 18 species studied by others (n = 39) revealed a high percentage (61.5 %) of obligatory self-incompatibility. Agamospermy was not recorded among the Caatinga studied species. The plant sexual systems in the Caatinga, despite the semi-arid climate, are similar to other tropical dry and wet forest communities, including those with high rainfall levels, except for the much lower percentage of dioecious species. The high frequency of self-incompatible species is similar to that reported for Savanna areas in Brazil, and also for dry (deciduous and semideciduous) and humid tropical forest communities.
