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Patrick J. Tranel - One of the best experts on this subject based on the ideXlab platform.
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hybridization potential between amaranthus Tuberculatus and amaranthus albus
bioRxiv, 2021Co-Authors: Brent P. Murphy, Laura A Chatham, D M Mccormick, Patrick J. TranelAbstract:The genus Amaranthus is composed of numerous annual herbs, several of which are primary driver weeds within annual production agricultural systems. In particular, Amaranthus Tuberculatus, a dioecious species, is noteworthy for rapid growth rates, high fecundity, and an expanding geographic distribution. Interspecific hybridization within and between the subgenera Amaranthus and Acnidia is reported both in controlled environment and field studies, however a gap in knowledge exists with the subgenus Albersia. Interspecific hybridization may contribute to genetic diversity, and may contribute to the current range expansion of A. Tuberculatus. Recently, a herbicide resistance survey of A. Tuberculatus across five Midwestern states reported alleles of PPX2 similar to sequences of Amaranthus albus, a monoecious species. Here, we seek to generate empirical data for the hybridization potential of A. albus and A. Tuberculatus through replicated, controlled crosses in a greenhouse. Of 65,000 progeny screened from A. albus grown with A. Tuberculatus males, three were confirmed as hybrids. Hybrids were dioecious, possessed phenotypic traits of both species, and had limited to no fertility. DNA content analysis of backcross progeny suggested a polyploid state may be required for hybrid formation. Screening of 120 progeny of A. Tuberculatus females grown with A. albus identified no hybrids, though a skew to female progeny was observed. The female skew may be due to apomixis or auto-pollination, the spontaneous generation of male flowers on otherwise female plants. Our results indicate that introgression between A. albus and A. Tuberculatus will occur less frequently than what has often been reported from hybridization studies with different pairs of Amaranthus species.
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genetic architecture underlying hppd inhibitor resistance in a nebraska amaranthus Tuberculatus population
bioRxiv, 2021Co-Authors: Brent P. Murphy, Roland Beffa, Patrick J. TranelAbstract:BACKGROUND: Amaranthus Tuberculatus is a primary driver weed species throughout the American Midwest. Inhibitors of 4-hydroxyphenylpyruvate dioxygenase (HPPD) are an important chemistry for weed management in numerous cropping systems. Here, we characterize the genetic architecture underlying the HPPD-inhibitor resistance trait in an A. Tuberculatus population (NEB). RESULTS: Dose-response studies of an F1 generation identified HPPD-inhibitor resistance as a dominant trait with a resistance/sensitive ratio of 15.0-21.1. Segregation analysis in a pseudo-F2 generation determined the trait is moderately heritable (H2 = 0.556), and complex. Bulk segregant analysis and validation with molecular markers identified two quantitative trait loci (QTL), one on each of Scaffold 4 and 12. CONCLUSIONS: Resistance to HPPD-inhibitors is a complex, largely dominant trait within the NEB population. Two large-effect QTL were identified controlling HPPD-inhibitor resistance in A. Tuberculatus. This is the first QTL mapping study to characterize herbicide resistance in a weedy species.
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genetic architecture underlying hppd inhibitor resistance in a nebraska amaranthus Tuberculatus population
Pest Management Science, 2021Co-Authors: Brent P. Murphy, Roland Beffa, Patrick J. TranelAbstract:BACKGROUND Amaranthus Tuberculatus is a problematic weed species in Midwest U.S.A. agricultural systems. Inhibitors of 4-hydroxyphenylpyruvate dioxygenase (HPPD) are an important chemistry for weed management in numerous cropping systems. Here, we characterize the genetic architecture underlying the HPPD-inhibitor resistance trait in an A. Tuberculatus population (NEB). RESULTS Dose-response studies of an F1 generation identified HPPD-inhibitor resistance as a dominant trait with a resistance factor of 15.0-21.1 based on dose required for 50% growth reduction. Segregation analysis in a pseudo-F2 generation determined the trait is moderately heritable (H2 = 0.556) and complex. Bulk segregant analysis and validation with molecular markers identified two quantitative trait loci (QTL), one on each of Scaffold 4 and 12. CONCLUSIONS Resistance to HPPD-inhibitors is a complex, largely dominant trait within the NEB population. Two large-effect QTL were identified controlling HPPD-inhibitor resistance in A. Tuberculatus. This is the first QTL mapping study to characterize herbicide resistance in a weedy species. This article is protected by copyright. All rights reserved.
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herbicide resistance in amaranthus Tuberculatus
Pest Management Science, 2021Co-Authors: Patrick J. TranelAbstract:Amaranthus Tuberculatus is the major weed species in many midwestern US row-crop production fields, and it is among the most problematic weeds in the world in terms of its ability to evolve herbicide resistance. It has now evolved resistance to herbicides spanning seven unique sites of action, with populations and even individual plants often possessing resistance to several herbicides/herbicide groups. Historically, herbicide target-site changes accounted for most of the known resistance mechanisms in this weed; however, over the last few years, non-target-site mechanisms, particularly enhanced herbicide detoxification, have become extremely common in A. Tuberculatus. Unravelling the genetics and molecular details of non-target-site resistance mechanisms, understanding the extent to which they confer cross resistance to other herbicides, and understanding how they evolve remain as critical research endeavors. Transcriptomic and genomics approaches are already facilitating such studies, the results of which hopefully will inform better resistance-mitigation strategies. The largely unprecedented level of herbicide resistance in A. Tuberculatus is not only a fascinating example of evolution in action, but it is a serious and growing threat to the sustainability of midwestern US cropping systems. © 2020 Society of Chemical Industry.
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Male-specific Y-chromosomal regions in waterhemp (Amaranthus Tuberculatus) and Palmer amaranth (Amaranthus palmeri).
The New phytologist, 2020Co-Authors: Jacob S. Montgomery, Darci A. Giacomini, Detlef Weigel, Patrick J. TranelAbstract:Amaranthus Tuberculatus and Amaranthus palmeri are agronomically important weed species, both with stable dioecious reproductive systems. An understanding of the genetic basis of sex determination may lead to new methods of managing these troublesome weeds. Previous research identified genomic sequences associated with maleness in each species. Male-specific sequences were used to identify genomic regions in both species that are believed to contain sex-determining genes, i.e. the male-specific Y (MSY) region. These regions were compared to understand if sex determination is controlled via the same physiological pathway and if dioecy evolved independently. A contiguously assembled candidate MSY region identified in Amaranthus palmeri is approximately 1.3 Mb with 121 predicted gene models. In Amaranthus Tuberculatus, several contigs, with combined length of 4.6 Mb and with 147 gene models, were identified as belonging to the MSY region. Synteny was not detected between the two species' candidate MSY regions but they shared two predicted genes. With lists of candidate genes for sex determination containing fewer than 200 in each species, future research can address whether sex determination is controlled via similar physiological pathways and whether dioecy has indeed evolved independently in these species.
Colin F J Odonnell - One of the best experts on this subject based on the ideXlab platform.
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conservation status and causes of decline of the threatened new zealand long tailed bat chalinolobus Tuberculatus chiroptera vespertilionidae
Mammal Review, 2000Co-Authors: Colin F J OdonnellAbstract:Historical anecdotes and preliminary monitoring since 1990 indicate that New Zealand Longtailed Bats (Chalinolobus Tuberculatus, Vespertilionidae) are now rare or absent at many sites where formerly they were common. Chalinolobus Tuberculatus appeared to be common throughout New Zealand in the 1800s but by 1900‐30 it was becoming scarce in many districts. Formal surveys in the South Island since 1990 either failed to find C. Tuberculatus ,o r recorded bats in low numbers. Of eight sites where transect counts were undertaken, bats were recorded frequently at two sites (45‐66% of counts; Eglinton and Dart Valleys), rarely at four sites (2.4‐10.7% of counts), and were not recorded at the remaining two sites despite considerable survey effort. Of 10 sites where stationary counts using automatic detector units were used, no C. Tuberculatus were recorded in three areas (153 nights combined), they were found rarely at six sites (2.1‐21.0% of nights; 461 nights combined) and were recorded commonly only in the Eglinton Valley (85% of 120 nights). Assertions that C. Tuberculatus are ‘common’ and that the conservation status is ‘secure’ are questionable and this review supports suggestions that the species should be classed as ‘Vulnerable’. Possible causes of decline have been suggested including clearance and logging of lowland forests, predation by introduced mammals and owls, competition for roost sites by introduced mammals, birds and wasps, and human interference and disturbance at roosting sites. However, authors’ claims have all been speculative and unsubstantiated. There has been no research undertaken to quantify these claims, and this is required urgently. The results of these preliminary surveys provide a new baseline against which future population trends might be compared. Increased effort using standardized monitoring techniques, applied at a national level, is required to confirm the possible trends and to help identify the best sites where conservation managers may attempt to restore the population level.
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use of roosts by the long tailed bat chalinolobus Tuberculatus in temperate rainforest in new zealand
Journal of Mammalogy, 1999Co-Authors: Colin F J Odonnell, Jane A SedgeleyAbstract:Patterns of roost-switching behavior and roost reuse were investigated in the threatened New Zealand long-tailed bat ( Chalinolobus Tuberculatus ) in temperate rainforest. A total of 371 roosts was monitored for 503 roost-days after radiotracking 58 bats. Bats were solitary (37.3%) or communal (62.7%). Colonies were small, averaging 34.7 bats ± 23.4 SD . Reproductive females dominated colonies, and males roosted more often by themselves. C. Tuberculatus differed from other species of bats because roost-site lability was extremely high (70% of sites occupied for only 1 night), bats did not cycle around a small number of preferred roosts, females carried their young to a new roost each day, and individuals abandoned each roost simultaneously as a group. Rates of reuse were low, with 301 new roost trees found >3 years of study. All sex and age classes switched frequently between solitary and communal roosts. Solitary roosts were occupied for longer times than colonial roosts. Reproductive females predominately (although not exclusively) used colonies during pregnancy and lactation but were more often solitary during post-lactation. Ratio of communal to solitary roosts in nonreproductive bats remained the same throughout summer, but adult males switched to communal roosts more often during post-lactation, presumably to mate. We suggest that suitable roosts were abundant allowing C. Tuberculatus to move frequently in response to social and thermoregulatory requirements. If the pool of suitable trees were reduced, population viability may be affected.
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roost selection by the long tailed bat chalinolobus Tuberculatus in temperate new zealand rainforest and its implications for the conservation of bats in managed forests
Biological Conservation, 1999Co-Authors: Jane A Sedgeley, Colin F J OdonnellAbstract:Abstract Roost selection by the threatened New Zealand long-tailed bat (Chalinolobus Tuberculatus) was examined in temperate beech (Nothofagus) rainforest in New Zealand. Seventy-three bats were radio-tracked during the summers of 1993–1997 to 304 roost cavities in 291 different trees. Roost tree and site characteristics were compared with those of 593 randomly selected trees. Bats selected roosts on the basis of topography, forest composition and tree characteristics. Ninety-five percent of roost trees were in mature, open-structured lowland forest on the relatively flat valley floor within 500 m of the forest edge. Four tree species (including dead trees) were used as day roosts. C. Tuberculatus did not discriminate between tree species per se, but selected roost trees on the basis of functional characteristics associated with these trees. Bats actively selected taller trees which had relatively low canopy closure, larger stem diameters, larger trunk surface areas and greater numbers of cavities than random trees. Red beech (Nothofagus fusca) and dead trees were most likely to provide these preferred characteristics. Seventy-four percent of roost trees were c. 100–>600 years of age. Such trees are targeted for removal under most forest management practices. Selection of specialised roosts, high roost lability and low levels of roost re-use indicate that C. Tuberculatus need large areas of mature forest. We predict that outside protected areas, the low availability of suitable roost trees may limit bat populations. ©
Roland Beffa - One of the best experts on this subject based on the ideXlab platform.
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genetic architecture underlying hppd inhibitor resistance in a nebraska amaranthus Tuberculatus population
bioRxiv, 2021Co-Authors: Brent P. Murphy, Roland Beffa, Patrick J. TranelAbstract:BACKGROUND: Amaranthus Tuberculatus is a primary driver weed species throughout the American Midwest. Inhibitors of 4-hydroxyphenylpyruvate dioxygenase (HPPD) are an important chemistry for weed management in numerous cropping systems. Here, we characterize the genetic architecture underlying the HPPD-inhibitor resistance trait in an A. Tuberculatus population (NEB). RESULTS: Dose-response studies of an F1 generation identified HPPD-inhibitor resistance as a dominant trait with a resistance/sensitive ratio of 15.0-21.1. Segregation analysis in a pseudo-F2 generation determined the trait is moderately heritable (H2 = 0.556), and complex. Bulk segregant analysis and validation with molecular markers identified two quantitative trait loci (QTL), one on each of Scaffold 4 and 12. CONCLUSIONS: Resistance to HPPD-inhibitors is a complex, largely dominant trait within the NEB population. Two large-effect QTL were identified controlling HPPD-inhibitor resistance in A. Tuberculatus. This is the first QTL mapping study to characterize herbicide resistance in a weedy species.
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genetic architecture underlying hppd inhibitor resistance in a nebraska amaranthus Tuberculatus population
Pest Management Science, 2021Co-Authors: Brent P. Murphy, Roland Beffa, Patrick J. TranelAbstract:BACKGROUND Amaranthus Tuberculatus is a problematic weed species in Midwest U.S.A. agricultural systems. Inhibitors of 4-hydroxyphenylpyruvate dioxygenase (HPPD) are an important chemistry for weed management in numerous cropping systems. Here, we characterize the genetic architecture underlying the HPPD-inhibitor resistance trait in an A. Tuberculatus population (NEB). RESULTS Dose-response studies of an F1 generation identified HPPD-inhibitor resistance as a dominant trait with a resistance factor of 15.0-21.1 based on dose required for 50% growth reduction. Segregation analysis in a pseudo-F2 generation determined the trait is moderately heritable (H2 = 0.556) and complex. Bulk segregant analysis and validation with molecular markers identified two quantitative trait loci (QTL), one on each of Scaffold 4 and 12. CONCLUSIONS Resistance to HPPD-inhibitors is a complex, largely dominant trait within the NEB population. Two large-effect QTL were identified controlling HPPD-inhibitor resistance in A. Tuberculatus. This is the first QTL mapping study to characterize herbicide resistance in a weedy species. This article is protected by copyright. All rights reserved.
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characterization of glyphosate resistance in amaranthus Tuberculatus populations
Journal of Agricultural and Food Chemistry, 2014Co-Authors: Lothar Lorentz, Todd A. Gaines, Philip Westra, Scott J Nissen, Harry Strek, Heinz W Dehne, J P Ruizsantaella, Roland BeffaAbstract:The evolution of glyphosate-resistant weeds has recently increased dramatically. Six suspected glyphosate-resistant Amaranthus Tuberculatus populations were studied to confirm resistance and determine the resistance mechanism. Resistance was confirmed in greenhouse for all six populations with glyphosate resistance factors (R/S) between 5.2 and 7.5. No difference in glyphosate absorption or translocation was observed between resistant and susceptible individuals. No mutation at amino acid positions G101, T102, or P106 was detected in the EPSPS gene coding sequence, the target enzyme of glyphosate. Analysis of EPSPS gene copy number revealed that all glyphosate-resistant populations possessed increased EPSPS gene copy number, and this correlated with increased expression at both RNA and protein levels. EPSPS Vmax and Kcat values were more than doubled in resistant plants, indicating higher levels of catalytically active expressed EPSPS protein. EPSPS gene amplification is the main mechanism contributing to glyphosate resistance in the A. Tuberculatus populations analyzed.
Todd A. Gaines - One of the best experts on this subject based on the ideXlab platform.
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metabolism of 2 4 dichlorophenoxyacetic acid contributes to resistance in a common waterhemp amaranthus Tuberculatus population
Pest Management Science, 2018Co-Authors: Marcelo Rodrigues Alves De Figueiredo, Todd A. Gaines, Philip Westra, Patrick J. Tranel, Lacy J Leibhart, Zachary J Reicher, Scott J Nissen, Mark L Bernards, Greg R Kruger, Mithila JugulamAbstract:BACKGROUND Synthetic auxins such as 2,4-dichlorophenoxyacetic acid (2,4-D) have been widely used for selective control of broadleaf weeds since the mid-1940s. In 2009, an Amaranthus Tuberculatus (common waterhemp) population with 10-fold resistance to 2,4-D was found in Nebraska, USA. The 2,4-D resistance mechanism was examined by conducting [14 C] 2,4-D absorption, translocation and metabolism experiments. RESULTS No differences were found in 2,4-D absorption or translocation between resistant and susceptible A. Tuberculatus plants. Resistant plants metabolized [14 C] 2,4-D more rapidly than did susceptible plants. The half-life of [14 C] 2,4-D in susceptible plants was 105 h, compared with 22 h in resistant plants. Pretreatment with the cytochrome P450 inhibitor malathion inhibited [14 C] 2,4-D metabolism in resistant plants and reduced the 2,4-D dose required for 50% growth inhibition (GR50 ) of resistant plants by 7-fold to 27 g ha-1 , similar to the GR50 for susceptible plants in the absence of malathion. CONCLUSION Our results demonstrate that rapid 2,4-D metabolism is a contributing factor to resistance in A. Tuberculatus, potentially mediated by cytochrome P450. Metabolism-based resistance to 2,4-D could pose a serious challenge for A. Tuberculatus control because of the potential for cross-resistance to other herbicides. © 2017 Society of Chemical Industry.
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Inheritance of Mesotrione Resistance in an Amaranthus Tuberculatus (var. rudis) Population from Nebraska, USA
Frontiers Media S.A., 2018Co-Authors: Maxwel C. Oliveira, Todd A. Gaines, Amit J. Jhala, Stevan Z. KnezevicAbstract:A population of Amaranthus Tuberculatus (var. rudis) evolved resistance to 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor herbicides (mesotrione, tembotrione, and topramezone) in Nebraska. The level of resistance was the highest to mesotrione, and the mechanism of resistance in this population is metabolism-based likely via cytochrome P450 enzymes. The increasing number of weeds resistant to herbicides warrants studies on the ecology and evolutionary factors contributing for resistance evolution, including inheritance of resistance traits. In this study, we investigated the genetic control of mesotrione resistance in an A. Tuberculatus population from Nebraska, USA. Results showed that reciprocal crosses in the F1 families exhibited nuclear inheritance, which allows pollen movement carrying herbicide resistance alleles. The mode of inheritance varied from incomplete recessive to incomplete dominance depending upon the F1 family. Observed segregation patterns for the majority of the F2 and back-cross susceptible (BC/S) families did not fit to a single major gene model. Therefore, multiple genes are likely to confer metabolism-based mesotrione resistance in this A. Tuberculatus population from Nebraska. The results of this study aid to understand the genetics and inheritance of a non-target-site based mesotrione resistant A. Tuberculatus population from Nebraska, USA
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Reversing resistance to tembotrione in an Amaranthus Tuberculatus (var. rudis) population from Nebraska, USA with cytochrome P450 inhibitors.
Pest management science, 2017Co-Authors: Maxwel C. Oliveira, Todd A. Gaines, Amit J. Jhala, Franck E. Dayan, Eric L. Patterson, Stevan Z. KnezevicAbstract:BACKGROUND A population of Amaranthus Tuberculatus (var. rudis) was confirmed resistant to 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibitor herbicides (mesotrione, tembotrione, and topramezone) in a seed corn/soybean rotation in Nebraska. Further investigation confirmed a non-target-site resistance mechanism in this population. The main objective of this study was to explore the role of cytochrome P450 inhibitors for restoring the efficacy of HPPD-inhibitor herbicides on the HPPD-inhibitor resistant A. Tuberculatus population from Nebraska, USA (HPPD-R). RESULTS Enhanced metabolism via cytochrome P450 enzymes is the mechanism of resistance in HPPD-R. Amitrole partially restored the activity of mesotrione, whereas malathion, amitrole, and piperonyl butoxide restored the activity of tembotrione and topramezone in HPPD-R. While corn was injured through malathion followed by mesotrione application a week after treatment, the injury was transient, and the crop recovered. CONCLUSION The use of cytochrome P450 inhibitors with tembotrione may provide a new way for controlling HPPD-inhibitor resistant A. Tuberculatus, but further research is needed to identify the cytochrome P450 candidate gene(s) conferring metabolism-based resistance. The results presented here aid to gain an insight into non-target-site resistance weed management strategies.
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characterization of glyphosate resistance in amaranthus Tuberculatus populations
Journal of Agricultural and Food Chemistry, 2014Co-Authors: Lothar Lorentz, Todd A. Gaines, Philip Westra, Scott J Nissen, Harry Strek, Heinz W Dehne, J P Ruizsantaella, Roland BeffaAbstract:The evolution of glyphosate-resistant weeds has recently increased dramatically. Six suspected glyphosate-resistant Amaranthus Tuberculatus populations were studied to confirm resistance and determine the resistance mechanism. Resistance was confirmed in greenhouse for all six populations with glyphosate resistance factors (R/S) between 5.2 and 7.5. No difference in glyphosate absorption or translocation was observed between resistant and susceptible individuals. No mutation at amino acid positions G101, T102, or P106 was detected in the EPSPS gene coding sequence, the target enzyme of glyphosate. Analysis of EPSPS gene copy number revealed that all glyphosate-resistant populations possessed increased EPSPS gene copy number, and this correlated with increased expression at both RNA and protein levels. EPSPS Vmax and Kcat values were more than doubled in resistant plants, indicating higher levels of catalytically active expressed EPSPS protein. EPSPS gene amplification is the main mechanism contributing to glyphosate resistance in the A. Tuberculatus populations analyzed.
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interspecific hybridization transfers a previously unknown glyphosate resistance mechanism in amaranthus species
Evolutionary Applications, 2012Co-Authors: Todd A. Gaines, Sarah M. Ward, Bekir Bukun, Christopher Preston, Jan E. Leach, Philip WestraAbstract:A previously unknown glyphosate resistance mechanism, amplification of the 5-enolpyruvyl shikimate-3-phosphate synthase gene, was recently reported in Amaranthus palmeri. This evolved mechanism could introgress to other weedy Amaranthus species through interspecific hybridization, representing an avenue for acquisition of a novel adaptive trait. The objective of this study was to evaluate the potential for this glyphosate resistance trait to transfer via pollen from A. palmeri to five other weedy Amaranthus species (Amaranthus hybridus, Amaranthus powellii, Amaranthus retroflexus, Amaranthus spinosus, and Amaranthus Tuberculatus). Field and greenhouse crosses were conducted using glyphosate-resistant male A. palmeri as pollen donors and the other Amaranthus species as pollen recipients. Hybridization between A. palmeri and A. spinosus occurred with frequencies in the field studies ranging from <0.01% to 0.4%, and 1.4% in greenhouse crosses. A majority of the A. spinosus × A. palmeri hybrids grown to flowering were monoecious and produced viable seed. Hybridization occurred in the field study between A. palmeri and A. Tuberculatus (<0.2%), and between A. palmeri and A. hybridus (<0.01%). This is the first documentation of hybridization between A. palmeri and both A. spinosus and A. hybridus.
Jane A Sedgeley - One of the best experts on this subject based on the ideXlab platform.
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quality of cavity microclimate as a factor influencing selection of maternity roosts by a tree dwelling bat chalinolobus Tuberculatus in new zealand
Journal of Applied Ecology, 2001Co-Authors: Jane A SedgeleyAbstract:Summary 1 Cavity quality is important for the productivity and survival of many species of tree-dwelling wildlife. Intensive land management practices, such as logging and agriculture, frequently reduce cavity availability and potentially affect the long-term viability of populations. 2 The New Zealand long-tailed bat Chalinolobus Tuberculatus selects roosts in small knot-hole cavities with specific structural properties relative to available cavities. They also change roosts daily among a large pool of different roosts. Such behaviour is likely to make C. Tuberculatus vulnerable to human-induced deterioration in roosting habitat. 3 This study represents a case study of the degree of sophistication sometimes required to assess availability and quality of roost sites, by testing whether roosts selected by C. Tuberculatus also have specific microclimates. 4 Selection for microclimate was demonstrated by comparing temperature and humidity inside unoccupied maternity roosts with available, apparently unused, knot-hole cavities, large trunk-hollows and ambient conditions. 5 Compared with ambient conditions, roost and available knot-hole cavities had stable microclimates displaying only small ranges in temperature and humidity. Temperature inside cavities was lower than ambient temperature in the day and was warmer (and peaked) at night. Humidity in cavities was constantly high. Mean temperatures within trunk-hollows (not known to be used by C. Tuberculatus) were cooler than mean ambient and roost temperatures, and temperature ranges in hollows were large and fluctuated similarly to ambient temperatures. 6 Compared with available cavities and hollows, roost cavities had higher minimum temperatures, and maximum temperatures occurred significantly later in the day and continued for significantly longer. Humidity ranges were less and high humidity was maintained for longer. 7 The results suggest that C. Tuberculatus selects maternity roost sites with microclimatic conditions that are likely to accrue substantial energetic benefits. Predicted energy savings for adult bats using roost cavities compared with available knot-holes were 1·1–3·3%, and compared with hollows 3·4–7·3%. Greater energy savings would occur at night and benefit non-volant young. 8 In order to evaluate adequately and mitigate the full impacts of land-use practices, there is a need for wider tests to provide direct evidence of interactions between habitat management, cavity provision and survival of cavity-dependent wildlife.
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use of roosts by the long tailed bat chalinolobus Tuberculatus in temperate rainforest in new zealand
Journal of Mammalogy, 1999Co-Authors: Colin F J Odonnell, Jane A SedgeleyAbstract:Patterns of roost-switching behavior and roost reuse were investigated in the threatened New Zealand long-tailed bat ( Chalinolobus Tuberculatus ) in temperate rainforest. A total of 371 roosts was monitored for 503 roost-days after radiotracking 58 bats. Bats were solitary (37.3%) or communal (62.7%). Colonies were small, averaging 34.7 bats ± 23.4 SD . Reproductive females dominated colonies, and males roosted more often by themselves. C. Tuberculatus differed from other species of bats because roost-site lability was extremely high (70% of sites occupied for only 1 night), bats did not cycle around a small number of preferred roosts, females carried their young to a new roost each day, and individuals abandoned each roost simultaneously as a group. Rates of reuse were low, with 301 new roost trees found >3 years of study. All sex and age classes switched frequently between solitary and communal roosts. Solitary roosts were occupied for longer times than colonial roosts. Reproductive females predominately (although not exclusively) used colonies during pregnancy and lactation but were more often solitary during post-lactation. Ratio of communal to solitary roosts in nonreproductive bats remained the same throughout summer, but adult males switched to communal roosts more often during post-lactation, presumably to mate. We suggest that suitable roosts were abundant allowing C. Tuberculatus to move frequently in response to social and thermoregulatory requirements. If the pool of suitable trees were reduced, population viability may be affected.
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roost selection by the long tailed bat chalinolobus Tuberculatus in temperate new zealand rainforest and its implications for the conservation of bats in managed forests
Biological Conservation, 1999Co-Authors: Jane A Sedgeley, Colin F J OdonnellAbstract:Abstract Roost selection by the threatened New Zealand long-tailed bat (Chalinolobus Tuberculatus) was examined in temperate beech (Nothofagus) rainforest in New Zealand. Seventy-three bats were radio-tracked during the summers of 1993–1997 to 304 roost cavities in 291 different trees. Roost tree and site characteristics were compared with those of 593 randomly selected trees. Bats selected roosts on the basis of topography, forest composition and tree characteristics. Ninety-five percent of roost trees were in mature, open-structured lowland forest on the relatively flat valley floor within 500 m of the forest edge. Four tree species (including dead trees) were used as day roosts. C. Tuberculatus did not discriminate between tree species per se, but selected roost trees on the basis of functional characteristics associated with these trees. Bats actively selected taller trees which had relatively low canopy closure, larger stem diameters, larger trunk surface areas and greater numbers of cavities than random trees. Red beech (Nothofagus fusca) and dead trees were most likely to provide these preferred characteristics. Seventy-four percent of roost trees were c. 100–>600 years of age. Such trees are targeted for removal under most forest management practices. Selection of specialised roosts, high roost lability and low levels of roost re-use indicate that C. Tuberculatus need large areas of mature forest. We predict that outside protected areas, the low availability of suitable roost trees may limit bat populations. ©