David Galbraith is a writer and researcher who serves as Head of Science at Canada's Royal Botanical Gardens. Trained as a wildlife biology, he also has extensive experience in building environmental networks, managing collections, and investigating cultural heritage and history. David is an adjunct biology professor at McMaster University, and a Fellow of the Royal Canadian Geographical Society and of The Explorers Club.
Multiple paternity is the occurrence within a single clutch of offspring fathered by more than on... more Multiple paternity is the occurrence within a single clutch of offspring fathered by more than one male. This pattern may be an an adaptive feature of the mating system of turtles. Mating systems are the adaptive features of reproduction which contribute lo variation in the probability of a particular egg being fertilized by a particular sperm. Turtle populations have rarely been studied specifically in terms of multiple paternity or mating systems. Five features related to multiple paternity are discussed: spacing behaviour prior to courtship, mate-seeking and mate choice, agonistic encounters between individuals, sperm storage, and sperm competition. Several studies have examined movements and spacing behaviours in turtles, and have drawn inferences about mate seeking. At present, multiple paternity has been detected in clutches of loggerhead turtles (Caretta carella), wood turtles (Clemmys insculpta), and snapping turtles (Chelydra serpentina). In wood turtles, a relationship be...
The Princess Point promontory at Cootes Paradise, Hamilton, Ontario has a long, rich history of h... more The Princess Point promontory at Cootes Paradise, Hamilton, Ontario has a long, rich history of human activity. This paper provides a synopsis of the archaeological work conducted on Princess Point, and summarizes the history of human activity on the promontory. The Princess Point site was discovered on the promontory in the 1960s by archaeologists from McMaster University. Excavations were conducted by McMaster in the late 1960s, and by the University of Toronto, Mississauga since 2000. These excavations demonstrate that Princess Point was used by native peoples from Early Archaic times (8000–6000 B.C.) through to the end of the Woodland period at A.D. 1650. The most intense occupation occurred during the Early Late Woodland period (A.D. 500–1000) by people of the Princess Point Complex. Euro-Canadians began using Princess Point during the late eighteenth century. In the twentieth century, the promontory was incorporated into the Royal Botanical Gardens.
Public gardens are contributing to ex-situ conservation, but do much more. We seek to better conn... more Public gardens are contributing to ex-situ conservation, but do much more. We seek to better connect people and plants, and make sure that people benefit from the sustainable use of plants. How can individual gardens link their work to the global scene and make the case that they are part of the biggest picture possible? Using the Global Strategy for Plant Conservation is a great way to do it: a flexible, non-binding list of targets ranging from conservation of species-at-risk to managing invasive species to education and capacity-building. This presentation is intended to spread awareness of the GSPC and share ideas on how the public garden community can support and benefit from the Strategy.
Introduced in 2000 by Botanic Gardens Conservation International, the International Agenda for Bo... more Introduced in 2000 by Botanic Gardens Conservation International, the International Agenda for Botanic Gardens in Conservation has now been adopted by over 400 botanic gardens and networks around the world. The registration process developed by BGCI invites institutions to use the International Agenda as a flexible, non-binding framework for their activities in conservation and sustainable development. As of 2006, 27 institutions in Canada have registered their participation in the International Agenda with BGCI. The International Agenda has had important effects on the network and communities of botanic gardens in Canada, including helping to generate funding support for educational and conservation programs, and in the development of the Biodiversity Action Plan for Botanic Gardens in Canada (2001), and in 2006 an update to the action plan and the nomination of Royal Botanical Gardens as the Canadian National Focal Point for the Global Strategy for Plant Conservation. In this pres...
Survivorship of adult female snapping turtles (Chelydra serpentina) in a marked population in Alg... more Survivorship of adult female snapping turtles (Chelydra serpentina) in a marked population in Algonquin Provincial Park, Ontario, was estimated using recapture records and catch-curve analysis of age structure. Known mortality was less than 1% per year, and a 13-year average of survivorship was 96.6% per year. Even the conservatively biased catch-curve estimate (92.9% per year) was among the highest yet reported for any turtle population. We compared two hypotheses to account for these high values. Although not at variance with our results, we rejected Rubner's proximal "rate of living" hypothesis because of lack of any other evidence that this process operates in reptiles. The second hypothesis was that high survivorship was the consequence of specific demographic features in a bet-hedging life-history strategy. Females would be more successful, given the high and stochastic clutch mortality and lack of predation on adults in this northern population, if they produced...
ABSTRACT Conservation genetics is principally concerned with 2 endeavours. The 1st approach uses ... more ABSTRACT Conservation genetics is principally concerned with 2 endeavours. The 1st approach uses genetic data to inform questions centred on relationships among individuals, populations, species or higher-level taxa. Such questions may relate to connectivity among populations (genefow) and the effects of past or present fragmentation events, forensic applications (animal or plant derivative identification) or the evolutionary affinities among taxa (phylogeny). The 2nd approach emphasizes quantification of genetic diversity at various hierarchical levels, to understand immediate (inbreeding) or future (ability to adapt to changing environments) consequences of reduced genetic variation. Relatively few populations of Canada’s 43 species of reptiles have been investigated using genetic techniques, which is unfortunate, because theory suggests these peripheral populations can harbour unique genetic variants, or be substantially genetically diverged from core populations. Examples from Canada and elsewhere can be used to illustrate some of the main sorts of inquiry within the 2 areas outlined above. Genetic markers have been useful in clarifying the bounds and affinities of reptile taxa and the related task of assessing the value of the taxon. Genetic markers can offer indirect measures of genefow/migration between populations, although these estimates are ideally anchored by ecological assessments (mark-recapture, radiotelemetry studies). Gene flow/migration is important in determining the proportion of genetic variation unique to a given population. Perhaps more practically, the extent to which populations are genetically connected determines the scale and geographic bounds of management units and the likelihood that a given population can recolonize an area where a neighbouring population has been extirpated. Small population size is correlated with the loss of genetic variation (for example, through founder effect or genetic drift), which may impair the future adaptive capacity of a population or species as a whole. Small population size also results in inbreeding, which can lead to the accumulation of deleterious alleles that reduce fitness and make the population decline further. Other applications of genetic markers include their use in determining the sex of individuals, important when the species is monomorphic, where the species is difficult to handle, or where only a sample of the individual is available. Genetic markers are also of use for investigations of mating systems. Which and how many males and females breed in a population may have important consequences for wild management, captive breeding, or reintroduction measures. Finally, genetic markers may be applied for forensic purposes: establishing the provenance or identity of an individual or part thereof. The relatively small proportion of Canadian reptiles genetically investigated is not a reflection of inadequate laboratory capacity or expertise. Our experience suggests there is a willing supply of both geneticists and students eager to carry out such work; financial resources are more often the limiting factor. Where resources are available, we suggest 3 areas of study that could contribute to Canadian reptile conservation: taxonomic studies, particularly where species are marked by geographic variation in morphology, or where the distribution of species is discontinuous or spans very different environments; studies of the conservation value of peripheral populations; and using genetic information and GIS tools to assess the effect of habitat disturbance on population connectivity over relatively short time scales.
... the significance of the Darwin finches' David A. Galbraith, Alexander M. Mills, and ... more ... the significance of the Darwin finches' David A. Galbraith, Alexander M. Mills, and Ronald J. Brooks ... Island Baltra Barrington Culpepper Duncan Floreana Fernandina Hood Isabela James Jervis Marchena Pinta San Cristobal Santa Cruz Tower Wenman ...
Page 1. J. Parasitol., 76(2), 1990, p. 190-195 ? American Society of Parasitologists 1990 OCCURRE... more Page 1. J. Parasitol., 76(2), 1990, p. 190-195 ? American Society of Parasitologists 1990 OCCURRENCE OF PLACOBDELLA PARASITICA (HIRUDINEA) ON SNAPPING TURTLES, CHELYDRA SERPENTINA, IN SOUTHEASTERN ONTARIO ...
Page 1. NOTES Journal of Herpetology, Vol. 21, No. 4, pp. 359-363, 1987 Copyright 1987 Society fo... more Page 1. NOTES Journal of Herpetology, Vol. 21, No. 4, pp. 359-363, 1987 Copyright 1987 Society for the Study of Amphibians and Reptiles Addition of Annual Growth Lines in Adult Snapping Turtles Chelydra serpentina DAVID ...
Evolution of population structure on islands is the result of physical processes linked to volcan... more Evolution of population structure on islands is the result of physical processes linked to volcanism, orogenic events, changes in sea level, as well as habitat variation. We assessed patterns of genetic structure in the giant tortoise of the Aldabra atoll, where previous ecological studies suggested population subdivisions as a result of landscape discontinuity due to unsuitable habitat and island separation. Analysis of mitochondrial DNA (mtDNA) control region sequences and allelic variation at 8 microsatellite loci were conducted on tortoises sampled in 3 locations on the 2 major islands of Aldabra. We found no variation in mtDNA sequences. This pattern corroborated earlier work supporting the occurrence of a founding event during the last interglacial period and a further reduction in genetic variability during historical time. On the other hand, significant population structure recorded at nuclear loci suggested allopatric divergence possibly due to geographical barriers among islands and ecological partitions hindering tortoise movements within islands. This is the first attempt to study the population genetics of Aldabra tortoises, which are now at carrying capacity in an isolated terrestrial ecosystem where ecological factors appear to have a strong influence on population dynamics.
We replicated DNA fingerprints of snapping turtles (Chelydra serpentina) and hypervariable restri... more We replicated DNA fingerprints of snapping turtles (Chelydra serpentina) and hypervariable restriction fragments of red-winged blackbirds (Agelaius phoeniceus) to estimate the between-blot and between-lane components of variance in molecular weights of restriction fragments. Molecular weight standards were included in every lane, and bands were sized using a sonic digitizer. In both studies, a strong positive correlation was found between band size and coefficient of variation (CV; mean = 0.7%). In the DNA fingerprint study, 26% of the variance in estimates of band size was due to differences between blots, 10% due to differences between lanes on the same blot, and 64% due to error in the digitizing process. In the restriction fragment length polymorphism (RFLP) study, 16% of the variance was due to difference between lanes, and 84% to digitizing. Statistical models were developed to measure the effect of sizing error on identifying identical fragments in different lanes or on different blots, in categorizing distinct alleles, and in determining the size of bins in operational allele definitions. We suggest that the distance between bands be at least 2.8 standard deviations (SD) before they are declared different at alpha = 0.05, and 3.7 SD for alpha = 0.01. A variation in CVs strongly indicates that empirical relationships between SD and band size must be used to decide if two bands represent the same allele. Alleles must be at least 3.9 SD apart before the chance of assigning new observations in error falls below 0.05. We suggest that a minimum bin width of 16 SD is necessary before the chances of assigning a band to the wrong bin falls below 0.05.
-- , AND J. VILLA R. 1986. Introduction to the herpetology of Costa Rica. Contr. to Herp., Soc. S... more -- , AND J. VILLA R. 1986. Introduction to the herpetology of Costa Rica. Contr. to Herp., Soc. Stud. Amph. Rept. 3:1-207. SCOTT, N. J. 1969. A zoogeographic analysis of the snakes of Costa Rica. Unpubl. Ph.D. dissert., Uni- versity of Southern California.
Multiple paternity is the occurrence within a single clutch of offspring fathered by more than on... more Multiple paternity is the occurrence within a single clutch of offspring fathered by more than one male. This pattern may be an an adaptive feature of the mating system of turtles. Mating systems are the adaptive features of reproduction which contribute lo variation in the probability of a particular egg being fertilized by a particular sperm. Turtle populations have rarely been studied specifically in terms of multiple paternity or mating systems. Five features related to multiple paternity are discussed: spacing behaviour prior to courtship, mate-seeking and mate choice, agonistic encounters between individuals, sperm storage, and sperm competition. Several studies have examined movements and spacing behaviours in turtles, and have drawn inferences about mate seeking. At present, multiple paternity has been detected in clutches of loggerhead turtles (Caretta carella), wood turtles (Clemmys insculpta), and snapping turtles (Chelydra serpentina). In wood turtles, a relationship be...
The Princess Point promontory at Cootes Paradise, Hamilton, Ontario has a long, rich history of h... more The Princess Point promontory at Cootes Paradise, Hamilton, Ontario has a long, rich history of human activity. This paper provides a synopsis of the archaeological work conducted on Princess Point, and summarizes the history of human activity on the promontory. The Princess Point site was discovered on the promontory in the 1960s by archaeologists from McMaster University. Excavations were conducted by McMaster in the late 1960s, and by the University of Toronto, Mississauga since 2000. These excavations demonstrate that Princess Point was used by native peoples from Early Archaic times (8000–6000 B.C.) through to the end of the Woodland period at A.D. 1650. The most intense occupation occurred during the Early Late Woodland period (A.D. 500–1000) by people of the Princess Point Complex. Euro-Canadians began using Princess Point during the late eighteenth century. In the twentieth century, the promontory was incorporated into the Royal Botanical Gardens.
Public gardens are contributing to ex-situ conservation, but do much more. We seek to better conn... more Public gardens are contributing to ex-situ conservation, but do much more. We seek to better connect people and plants, and make sure that people benefit from the sustainable use of plants. How can individual gardens link their work to the global scene and make the case that they are part of the biggest picture possible? Using the Global Strategy for Plant Conservation is a great way to do it: a flexible, non-binding list of targets ranging from conservation of species-at-risk to managing invasive species to education and capacity-building. This presentation is intended to spread awareness of the GSPC and share ideas on how the public garden community can support and benefit from the Strategy.
Introduced in 2000 by Botanic Gardens Conservation International, the International Agenda for Bo... more Introduced in 2000 by Botanic Gardens Conservation International, the International Agenda for Botanic Gardens in Conservation has now been adopted by over 400 botanic gardens and networks around the world. The registration process developed by BGCI invites institutions to use the International Agenda as a flexible, non-binding framework for their activities in conservation and sustainable development. As of 2006, 27 institutions in Canada have registered their participation in the International Agenda with BGCI. The International Agenda has had important effects on the network and communities of botanic gardens in Canada, including helping to generate funding support for educational and conservation programs, and in the development of the Biodiversity Action Plan for Botanic Gardens in Canada (2001), and in 2006 an update to the action plan and the nomination of Royal Botanical Gardens as the Canadian National Focal Point for the Global Strategy for Plant Conservation. In this pres...
Survivorship of adult female snapping turtles (Chelydra serpentina) in a marked population in Alg... more Survivorship of adult female snapping turtles (Chelydra serpentina) in a marked population in Algonquin Provincial Park, Ontario, was estimated using recapture records and catch-curve analysis of age structure. Known mortality was less than 1% per year, and a 13-year average of survivorship was 96.6% per year. Even the conservatively biased catch-curve estimate (92.9% per year) was among the highest yet reported for any turtle population. We compared two hypotheses to account for these high values. Although not at variance with our results, we rejected Rubner's proximal "rate of living" hypothesis because of lack of any other evidence that this process operates in reptiles. The second hypothesis was that high survivorship was the consequence of specific demographic features in a bet-hedging life-history strategy. Females would be more successful, given the high and stochastic clutch mortality and lack of predation on adults in this northern population, if they produced...
ABSTRACT Conservation genetics is principally concerned with 2 endeavours. The 1st approach uses ... more ABSTRACT Conservation genetics is principally concerned with 2 endeavours. The 1st approach uses genetic data to inform questions centred on relationships among individuals, populations, species or higher-level taxa. Such questions may relate to connectivity among populations (genefow) and the effects of past or present fragmentation events, forensic applications (animal or plant derivative identification) or the evolutionary affinities among taxa (phylogeny). The 2nd approach emphasizes quantification of genetic diversity at various hierarchical levels, to understand immediate (inbreeding) or future (ability to adapt to changing environments) consequences of reduced genetic variation. Relatively few populations of Canada’s 43 species of reptiles have been investigated using genetic techniques, which is unfortunate, because theory suggests these peripheral populations can harbour unique genetic variants, or be substantially genetically diverged from core populations. Examples from Canada and elsewhere can be used to illustrate some of the main sorts of inquiry within the 2 areas outlined above. Genetic markers have been useful in clarifying the bounds and affinities of reptile taxa and the related task of assessing the value of the taxon. Genetic markers can offer indirect measures of genefow/migration between populations, although these estimates are ideally anchored by ecological assessments (mark-recapture, radiotelemetry studies). Gene flow/migration is important in determining the proportion of genetic variation unique to a given population. Perhaps more practically, the extent to which populations are genetically connected determines the scale and geographic bounds of management units and the likelihood that a given population can recolonize an area where a neighbouring population has been extirpated. Small population size is correlated with the loss of genetic variation (for example, through founder effect or genetic drift), which may impair the future adaptive capacity of a population or species as a whole. Small population size also results in inbreeding, which can lead to the accumulation of deleterious alleles that reduce fitness and make the population decline further. Other applications of genetic markers include their use in determining the sex of individuals, important when the species is monomorphic, where the species is difficult to handle, or where only a sample of the individual is available. Genetic markers are also of use for investigations of mating systems. Which and how many males and females breed in a population may have important consequences for wild management, captive breeding, or reintroduction measures. Finally, genetic markers may be applied for forensic purposes: establishing the provenance or identity of an individual or part thereof. The relatively small proportion of Canadian reptiles genetically investigated is not a reflection of inadequate laboratory capacity or expertise. Our experience suggests there is a willing supply of both geneticists and students eager to carry out such work; financial resources are more often the limiting factor. Where resources are available, we suggest 3 areas of study that could contribute to Canadian reptile conservation: taxonomic studies, particularly where species are marked by geographic variation in morphology, or where the distribution of species is discontinuous or spans very different environments; studies of the conservation value of peripheral populations; and using genetic information and GIS tools to assess the effect of habitat disturbance on population connectivity over relatively short time scales.
... the significance of the Darwin finches' David A. Galbraith, Alexander M. Mills, and ... more ... the significance of the Darwin finches' David A. Galbraith, Alexander M. Mills, and Ronald J. Brooks ... Island Baltra Barrington Culpepper Duncan Floreana Fernandina Hood Isabela James Jervis Marchena Pinta San Cristobal Santa Cruz Tower Wenman ...
Page 1. J. Parasitol., 76(2), 1990, p. 190-195 ? American Society of Parasitologists 1990 OCCURRE... more Page 1. J. Parasitol., 76(2), 1990, p. 190-195 ? American Society of Parasitologists 1990 OCCURRENCE OF PLACOBDELLA PARASITICA (HIRUDINEA) ON SNAPPING TURTLES, CHELYDRA SERPENTINA, IN SOUTHEASTERN ONTARIO ...
Page 1. NOTES Journal of Herpetology, Vol. 21, No. 4, pp. 359-363, 1987 Copyright 1987 Society fo... more Page 1. NOTES Journal of Herpetology, Vol. 21, No. 4, pp. 359-363, 1987 Copyright 1987 Society for the Study of Amphibians and Reptiles Addition of Annual Growth Lines in Adult Snapping Turtles Chelydra serpentina DAVID ...
Evolution of population structure on islands is the result of physical processes linked to volcan... more Evolution of population structure on islands is the result of physical processes linked to volcanism, orogenic events, changes in sea level, as well as habitat variation. We assessed patterns of genetic structure in the giant tortoise of the Aldabra atoll, where previous ecological studies suggested population subdivisions as a result of landscape discontinuity due to unsuitable habitat and island separation. Analysis of mitochondrial DNA (mtDNA) control region sequences and allelic variation at 8 microsatellite loci were conducted on tortoises sampled in 3 locations on the 2 major islands of Aldabra. We found no variation in mtDNA sequences. This pattern corroborated earlier work supporting the occurrence of a founding event during the last interglacial period and a further reduction in genetic variability during historical time. On the other hand, significant population structure recorded at nuclear loci suggested allopatric divergence possibly due to geographical barriers among islands and ecological partitions hindering tortoise movements within islands. This is the first attempt to study the population genetics of Aldabra tortoises, which are now at carrying capacity in an isolated terrestrial ecosystem where ecological factors appear to have a strong influence on population dynamics.
We replicated DNA fingerprints of snapping turtles (Chelydra serpentina) and hypervariable restri... more We replicated DNA fingerprints of snapping turtles (Chelydra serpentina) and hypervariable restriction fragments of red-winged blackbirds (Agelaius phoeniceus) to estimate the between-blot and between-lane components of variance in molecular weights of restriction fragments. Molecular weight standards were included in every lane, and bands were sized using a sonic digitizer. In both studies, a strong positive correlation was found between band size and coefficient of variation (CV; mean = 0.7%). In the DNA fingerprint study, 26% of the variance in estimates of band size was due to differences between blots, 10% due to differences between lanes on the same blot, and 64% due to error in the digitizing process. In the restriction fragment length polymorphism (RFLP) study, 16% of the variance was due to difference between lanes, and 84% to digitizing. Statistical models were developed to measure the effect of sizing error on identifying identical fragments in different lanes or on different blots, in categorizing distinct alleles, and in determining the size of bins in operational allele definitions. We suggest that the distance between bands be at least 2.8 standard deviations (SD) before they are declared different at alpha = 0.05, and 3.7 SD for alpha = 0.01. A variation in CVs strongly indicates that empirical relationships between SD and band size must be used to decide if two bands represent the same allele. Alleles must be at least 3.9 SD apart before the chance of assigning new observations in error falls below 0.05. We suggest that a minimum bin width of 16 SD is necessary before the chances of assigning a band to the wrong bin falls below 0.05.
-- , AND J. VILLA R. 1986. Introduction to the herpetology of Costa Rica. Contr. to Herp., Soc. S... more -- , AND J. VILLA R. 1986. Introduction to the herpetology of Costa Rica. Contr. to Herp., Soc. Stud. Amph. Rept. 3:1-207. SCOTT, N. J. 1969. A zoogeographic analysis of the snakes of Costa Rica. Unpubl. Ph.D. dissert., Uni- versity of Southern California.
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