The fungus-farming ant genus Cyatta (Formicidae: Myrmicinae) is represented by a single species, ... more The fungus-farming ant genus Cyatta (Formicidae: Myrmicinae) is represented by a single species, C. abscondita Sosa-Calvo et al., known from a few localities in Brazil (in the states of Ceará, Minas Gerais, São Paulo and the Distrito Federal), and a single locality in the Misiones province, Argentina. Cyatta is known to occur predominantly in savanna habitats and occasionally in the transition zones between the Atlantic Forest and Cerrado. The new records reported here significantly expand the previously known distribution of Cyatta abscondita and provide further support for the intimate relation between this species and the savannas of South America. We report the first occurrence of the genus in southern Brazil (Paraná state) and the westernmost occurrence (Bolivia) of Cyatta abscondita, which extend its distribution approximately 1450 km to the west. Finally, we discuss the importance of mapping inconspicuous species in order to develop strategies for protecting endangered areas and to increase our understanding of the evolutionary history of organisms and biomes.
tEcologists often seek sampling protocols that are both effective and relatively simple, i.e. tho... more tEcologists often seek sampling protocols that are both effective and relatively simple, i.e. those thatprovide a balance between the advantages obtained through sampling completeness and the costsinvolved in species sorting. Here we explored ways of simplifying a protocol devised for assessing geo-graphic patterns of ant species richness and composition in the savanna-dominated Cerrado landscapeof central Brazil. This protocol, which retrieved up to 88.5% of the expected number of species, wasemployed in five different sites located up to 1200 km apart from each other. In each site three transects(>1 km apart) were established, and within each transect 80 arboreal and 80 ground pitfall traps wereinstalled. We then evaluated the degree of congruence in species richness and composition between dataoriginated from the full data set and various subsets of the data, that either contained a reduced numberof samples (in different spatial configurations) or potential surrogates of the entire ant fauna. Our mainfindings show that by sorting specimens from just a subset of the ant genera we retrieved most of theinformation existing in the full data set, even though the amount of work involved in ant sorting wasreduced by about 50%. Reducing the number of samples taken in each site, as expected, also reducedthe amount of work involved in ant sorting. However, in most of our analyses the level of congruencewith the full data set was lower and/or became more erratic when sampling intensity was reduced toone-third or less of the original number of samples. More species were retrieved when samples werespread over multiple transects than when they were located in only one or two transects, indicating thateven at relatively small scales (a few kilometers) there is a turnover of ant species within the same typeof habitat. Based on these results we suggest that at least half of the samples from our original protocolare necessary to adequately describe large-scale patterns of ant species richness and beta diversity inNeotropical savannas. We also suggest that, whenever possible, sampling within a given site should bedone in multiple locations in order to maximize the number of species collected.
1. The idea that variable fire regimes (pyrodiversity) may increase habitat heterogeneity and, co... more 1. The idea that variable fire regimes (pyrodiversity) may increase habitat heterogeneity and, consequently, increase biodiversity at the landscape level is a relatively old one. However, this idea has been recently challenged by studies showing that the biota of fire-prone ecosystems is so resilient to fire that variation in fire regime has little ecological consequences. 2. We evaluated how communities of ants–a dominant faunal group–differ with variation in the frequency and seasonal timing of fire in Brazilian Cerrado(savanna), a global biodiversity hotspot. We compared the number and composition of ant species foraging on the ground and in trees among experimental treatments with three fire frequencies (unburned for 37 years and burned every 2 or 4 years for the past 16 years) and three seasonal timings (early, mid and late dry season) of fire with a biennial frequency. 3. There were no significant differences in ant species richness in trees, and there were no sig-nificant differences in the richness of ground-dwelling ants among plots burned at different times of the dry season. However, unburned plots had fewer ground-dwelling ant species than those burned at 2 or 4 year intervals. We detected marked differences in species composition across regimes varying in both the frequency and the timing of fire, which were related to fire-induced changes in vegetation structure. Over 40% of the overall ant species richness recorded in our study site was attributed to differences in species composition among fire treatments. 4. Synthesis and applications.Our study shows that Cerrado ant diversity at the landscape scale is promoted by a diversity of fire regimes, and therefore supports the validity of the pyrodiversity–biodiversity hypothesis for the Cerrado biome. Our findings suggest that the current policy of fire suppression in Cerrado protected areas has a negative effect on overall biodiversity and therefore should be reconsidered.
Ecologists often seek sampling protocols that are both effective and relatively simple... more Ecologists often seek sampling protocols that are both effective and relatively simple, i.e. those that provide a balance between the advantages obtained through sampling completeness and the costs involved in species sorting. Here we explored ways of simplifying a protocol devised for assessing geo-graphic patterns of ant species richness and composition in the savanna-dominated Cerrado landscape of central Brazil. This protocol, which retrieved up to 88.5% of the expected number of species, was employed in five different sites located up to 1200 km apart from each other. In each site three transects (>1 km apart) were established, and within each transect 80 arboreal and 80 ground pitfall traps were installed. We then evaluated the degree of congruence in species richness and composition between data originated from the full data set and various subsets of the data, that either contained a reduced number of samples (in different spatial configurations) or potential surrogates of the entire ant fauna. Our main findings show that by sorting specimens from just a subset of the ant genera we retrieved most of the information existing in the full data set, even though the amount of work involved in ant sorting was reduced by about 50%. Reducing the number of samples taken in each site, as expected, also reduced the amount of work involved in ant sorting. However, in most of our analyses the level of congruence with the full data set was lower and/or became more erratic when sampling intensity was reduced to one-third or less of the original number of samples. More species were retrieved when samples were spread over multiple transects than when they were located in only one or two transects, indicating that even at relatively small scales (a few kilometers) there is a turnover of ant species within the same type of habitat. Based on these results we suggest that at least half of the samples from our original protocol are necessary to adequately describe large-scale patterns of ant species richness and beta diversity in Neotropical savannas. We also suggest that, whenever possible, sampling within a given site should be done in multiple locations in order to maximize the number of species collected.
The fungus-farming ant genus Cyatta (Formicidae: Myrmicinae) is represented by a single species, ... more The fungus-farming ant genus Cyatta (Formicidae: Myrmicinae) is represented by a single species, C. abscondita Sosa-Calvo et al., known from a few localities in Brazil (in the states of Ceará, Minas Gerais, São Paulo and the Distrito Federal), and a single locality in the Misiones province, Argentina. Cyatta is known to occur predominantly in savanna habitats and occasionally in the transition zones between the Atlantic Forest and Cerrado. The new records reported here significantly expand the previously known distribution of Cyatta abscondita and provide further support for the intimate relation between this species and the savannas of South America. We report the first occurrence of the genus in southern Brazil (Paraná state) and the westernmost occurrence (Bolivia) of Cyatta abscondita, which extend its distribution approximately 1450 km to the west. Finally, we discuss the importance of mapping inconspicuous species in order to develop strategies for protecting endangered areas and to increase our understanding of the evolutionary history of organisms and biomes.
tEcologists often seek sampling protocols that are both effective and relatively simple, i.e. tho... more tEcologists often seek sampling protocols that are both effective and relatively simple, i.e. those thatprovide a balance between the advantages obtained through sampling completeness and the costsinvolved in species sorting. Here we explored ways of simplifying a protocol devised for assessing geo-graphic patterns of ant species richness and composition in the savanna-dominated Cerrado landscapeof central Brazil. This protocol, which retrieved up to 88.5% of the expected number of species, wasemployed in five different sites located up to 1200 km apart from each other. In each site three transects(>1 km apart) were established, and within each transect 80 arboreal and 80 ground pitfall traps wereinstalled. We then evaluated the degree of congruence in species richness and composition between dataoriginated from the full data set and various subsets of the data, that either contained a reduced numberof samples (in different spatial configurations) or potential surrogates of the entire ant fauna. Our mainfindings show that by sorting specimens from just a subset of the ant genera we retrieved most of theinformation existing in the full data set, even though the amount of work involved in ant sorting wasreduced by about 50%. Reducing the number of samples taken in each site, as expected, also reducedthe amount of work involved in ant sorting. However, in most of our analyses the level of congruencewith the full data set was lower and/or became more erratic when sampling intensity was reduced toone-third or less of the original number of samples. More species were retrieved when samples werespread over multiple transects than when they were located in only one or two transects, indicating thateven at relatively small scales (a few kilometers) there is a turnover of ant species within the same typeof habitat. Based on these results we suggest that at least half of the samples from our original protocolare necessary to adequately describe large-scale patterns of ant species richness and beta diversity inNeotropical savannas. We also suggest that, whenever possible, sampling within a given site should bedone in multiple locations in order to maximize the number of species collected.
1. The idea that variable fire regimes (pyrodiversity) may increase habitat heterogeneity and, co... more 1. The idea that variable fire regimes (pyrodiversity) may increase habitat heterogeneity and, consequently, increase biodiversity at the landscape level is a relatively old one. However, this idea has been recently challenged by studies showing that the biota of fire-prone ecosystems is so resilient to fire that variation in fire regime has little ecological consequences. 2. We evaluated how communities of ants–a dominant faunal group–differ with variation in the frequency and seasonal timing of fire in Brazilian Cerrado(savanna), a global biodiversity hotspot. We compared the number and composition of ant species foraging on the ground and in trees among experimental treatments with three fire frequencies (unburned for 37 years and burned every 2 or 4 years for the past 16 years) and three seasonal timings (early, mid and late dry season) of fire with a biennial frequency. 3. There were no significant differences in ant species richness in trees, and there were no sig-nificant differences in the richness of ground-dwelling ants among plots burned at different times of the dry season. However, unburned plots had fewer ground-dwelling ant species than those burned at 2 or 4 year intervals. We detected marked differences in species composition across regimes varying in both the frequency and the timing of fire, which were related to fire-induced changes in vegetation structure. Over 40% of the overall ant species richness recorded in our study site was attributed to differences in species composition among fire treatments. 4. Synthesis and applications.Our study shows that Cerrado ant diversity at the landscape scale is promoted by a diversity of fire regimes, and therefore supports the validity of the pyrodiversity–biodiversity hypothesis for the Cerrado biome. Our findings suggest that the current policy of fire suppression in Cerrado protected areas has a negative effect on overall biodiversity and therefore should be reconsidered.
Ecologists often seek sampling protocols that are both effective and relatively simple... more Ecologists often seek sampling protocols that are both effective and relatively simple, i.e. those that provide a balance between the advantages obtained through sampling completeness and the costs involved in species sorting. Here we explored ways of simplifying a protocol devised for assessing geo-graphic patterns of ant species richness and composition in the savanna-dominated Cerrado landscape of central Brazil. This protocol, which retrieved up to 88.5% of the expected number of species, was employed in five different sites located up to 1200 km apart from each other. In each site three transects (>1 km apart) were established, and within each transect 80 arboreal and 80 ground pitfall traps were installed. We then evaluated the degree of congruence in species richness and composition between data originated from the full data set and various subsets of the data, that either contained a reduced number of samples (in different spatial configurations) or potential surrogates of the entire ant fauna. Our main findings show that by sorting specimens from just a subset of the ant genera we retrieved most of the information existing in the full data set, even though the amount of work involved in ant sorting was reduced by about 50%. Reducing the number of samples taken in each site, as expected, also reduced the amount of work involved in ant sorting. However, in most of our analyses the level of congruence with the full data set was lower and/or became more erratic when sampling intensity was reduced to one-third or less of the original number of samples. More species were retrieved when samples were spread over multiple transects than when they were located in only one or two transects, indicating that even at relatively small scales (a few kilometers) there is a turnover of ant species within the same type of habitat. Based on these results we suggest that at least half of the samples from our original protocol are necessary to adequately describe large-scale patterns of ant species richness and beta diversity in Neotropical savannas. We also suggest that, whenever possible, sampling within a given site should be done in multiple locations in order to maximize the number of species collected.
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Papers by Jonas Maravalhas
2. We evaluated how communities of ants–a dominant faunal group–differ with variation in the frequency and seasonal timing of fire in Brazilian Cerrado(savanna), a global biodiversity hotspot. We compared the number and composition of ant species foraging on the ground and in trees among experimental treatments with three fire frequencies (unburned for 37 years and burned every 2 or 4 years for the past 16 years) and three seasonal timings (early, mid and late dry season) of fire with a biennial frequency.
3. There were no significant differences in ant species richness in trees, and there were no sig-nificant differences in the richness of ground-dwelling ants among plots burned at different times of the dry season. However, unburned plots had fewer ground-dwelling ant species than those burned at 2 or 4 year intervals. We detected marked differences in species composition across regimes varying in both the frequency and the timing of fire, which were related to fire-induced changes in vegetation structure. Over 40% of the overall ant species richness recorded in our study site was attributed to differences in species composition among fire treatments.
4. Synthesis and applications.Our study shows that Cerrado ant diversity at the landscape scale is promoted by a diversity of fire regimes, and therefore supports the validity of the pyrodiversity–biodiversity hypothesis for the Cerrado biome. Our findings suggest that the current policy of fire suppression in Cerrado protected areas has a negative effect on overall biodiversity and therefore should be reconsidered.
findings show that by sorting specimens from just a subset of the ant genera we retrieved most of the information existing in the full data set, even though the amount of work involved in ant sorting was reduced by about 50%. Reducing the number of samples taken in each site, as expected, also reduced the amount of work involved in ant sorting. However, in most of our analyses the level of congruence with the full data set was lower and/or became more erratic when sampling intensity was reduced to one-third or less of the original number of samples. More species were retrieved when samples were spread over multiple transects than when they were located in only one or two transects, indicating that even at relatively small scales (a few kilometers) there is a turnover of ant species within the same type of habitat. Based on these results we suggest that at least half of the samples from our original protocol are necessary to adequately describe large-scale patterns of ant species richness and beta diversity in Neotropical savannas. We also suggest that, whenever possible, sampling within a given site should be done in multiple locations in order to maximize the number of species collected.
2. We evaluated how communities of ants–a dominant faunal group–differ with variation in the frequency and seasonal timing of fire in Brazilian Cerrado(savanna), a global biodiversity hotspot. We compared the number and composition of ant species foraging on the ground and in trees among experimental treatments with three fire frequencies (unburned for 37 years and burned every 2 or 4 years for the past 16 years) and three seasonal timings (early, mid and late dry season) of fire with a biennial frequency.
3. There were no significant differences in ant species richness in trees, and there were no sig-nificant differences in the richness of ground-dwelling ants among plots burned at different times of the dry season. However, unburned plots had fewer ground-dwelling ant species than those burned at 2 or 4 year intervals. We detected marked differences in species composition across regimes varying in both the frequency and the timing of fire, which were related to fire-induced changes in vegetation structure. Over 40% of the overall ant species richness recorded in our study site was attributed to differences in species composition among fire treatments.
4. Synthesis and applications.Our study shows that Cerrado ant diversity at the landscape scale is promoted by a diversity of fire regimes, and therefore supports the validity of the pyrodiversity–biodiversity hypothesis for the Cerrado biome. Our findings suggest that the current policy of fire suppression in Cerrado protected areas has a negative effect on overall biodiversity and therefore should be reconsidered.
findings show that by sorting specimens from just a subset of the ant genera we retrieved most of the information existing in the full data set, even though the amount of work involved in ant sorting was reduced by about 50%. Reducing the number of samples taken in each site, as expected, also reduced the amount of work involved in ant sorting. However, in most of our analyses the level of congruence with the full data set was lower and/or became more erratic when sampling intensity was reduced to one-third or less of the original number of samples. More species were retrieved when samples were spread over multiple transects than when they were located in only one or two transects, indicating that even at relatively small scales (a few kilometers) there is a turnover of ant species within the same type of habitat. Based on these results we suggest that at least half of the samples from our original protocol are necessary to adequately describe large-scale patterns of ant species richness and beta diversity in Neotropical savannas. We also suggest that, whenever possible, sampling within a given site should be done in multiple locations in order to maximize the number of species collected.