Papers by Gabriela Ibarguchi
Biodiversity, 2014
ABSTRACT Globally, arid lands are under increasing pressure from growing populations and anthropo... more ABSTRACT Globally, arid lands are under increasing pressure from growing populations and anthropogenic disturbance from resource extraction, water diversion, introduced species, pollution and inadequate management for long-term sustainability. Biodiversity in dry regions, already at the physiological and energy limits for survival, may be particularly threatened by disturbance and the complex effects of climate change. Arid environments harbour unique endemic species and evolutionary novelty, and must be considered as conservation priorities. Here the cold arid lands of South America are highlighted, with examples of unique lineages and brief overviews of emerging issues threatening these ecosystems.
Journal of Avian Biology, 2011
Many seabirds exhibit high natal philopatry despite their extreme dispersal ability and delayed r... more Many seabirds exhibit high natal philopatry despite their extreme dispersal ability and delayed reproduction, and some exhibit phenotypic clustering in colonies and fostering or adoption of neighbouring chicks. Previous investigations of kinship in a small thick-billed murre colony Uria lomvia (Alcidae) in Norway revealed high relatedness among breeders on cliff ledges. To investigate the presence of kin groups and within-colony genetic sub-structuring elsewhere, we investigated kinship within a larger murre colony on Coats Island, Nunavut, Canada. Morphological (five characters) and genetic data (five microsatellite loci and a fragment of the mitochondrial cytochrome b gene) were analysed. Strong morphological differentiation was found among ledges. Genetic structuring was overall weak but significant at the coarse scale for males among ledges and on the east vs. the west side of the colony. Global spatial autocorrelation analyses did not detect consistent, widespread spatial patterns, although local 2D analyses provided some evidence of a tendency for larger neighbourhood sizes for females and a broad range of small to large neighbourhoods for males. Average withinledge relatedness was low overall, but ranged widely from slightly unrelated to greater than the level of cousins in both sexes. Kin-level relationships occurred on ledges more frequently for same-sex groups than expected by chance, suggesting that recruiting breeders (especially females) avoid or are unable to settle directly adjacent to relatives particularly of the opposite sex. Behavioural studies of natal dispersal of murres at Coats I. indicating that both sexes are highly philopatric, but that up to one-fifth of females may disperse, are concordant with this study. Overall, structuring was weaker than in Norway, and may be explained in part by genetic marker and sampling artifacts, and by the lack of genetic equilibrium suspected in the much larger Canadian Arctic colony. Natal philopatry may be an important factor driving the diversification of seabirds and kin groups in other colonies and species and may be more widespread than is currently acknowledged.
Polar Research
Arctic environmental changes already impact regional ecosystems, economies and northern communiti... more Arctic environmental changes already impact regional ecosystems, economies and northern communities, and are having increasing influence on many aspects of the global system. Interest in the Arctic has increased in concert with our improved awareness of potential changes; however, research funding has not necessarily kept pace with the need to improve our understanding of Arctic system change to inform evidence-based decision making. Analyses of data on research funding trends (2003-14) in Canada, the USA and the EU indicate that less than 3% of the total budget the funding agencies considered is allocated in any given year to Arctic-related research. Furthermore, alignment is uneven among established scientific research priorities, existing societal needs and projects awarded funding. New support mechanisms and improved alignment among resources, expertise and priorities, including Indigenous research priorities, are vital to planning and adaptation in the face of ongoing Arctic change.
Polar Research, 2018
Arctic environmental changes already impact regional ecosystems, economies and northern communiti... more Arctic environmental changes already impact regional ecosystems, economies and northern communities, and are having increasing influence on many aspects of the global system. Interest in the Arctic has increased in concert with our improved awareness of potential changes; however, research funding has not necessarily kept pace with the need to improve our understanding of Arctic system change to inform evidence-based decision making. Analyses of data on research funding trends (2003-14) in Canada, the USA and the EU indicate that less than 3% of the total budget the funding agencies considered is allocated in any given year to Arctic-related research. Furthermore, alignment is uneven among established scientific research priorities, existing societal needs and projects awarded funding. New support mechanisms and improved alignment among resources, expertise and priorities, including Indigenous research priorities, are vital to planning and adaptation in the face of ongoing Arctic change.
Because of convergence in morphology and fragmented fossil records of avian taxa phylogeny recons... more Because of convergence in morphology and fragmented fossil records of avian taxa phylogeny reconstruction has been difficult for some groups. Estimated ages of appearance of bird orders may vary widely depending on the type of evidence used (e.g. fossil versus molecular). The K/T boundary marks the extinction of many organisms, but the number of taxa affected and the degree of speciation before and after this time period are debated. This study analysed sequences of mitochondrial cytochrome b and 12S rRNA genes to determine whether the Order Craciformes (formerly in Galliformes), basal to Neornithes, appeared and radiated before or after the K/T boundary. Phylogenetic analyses revealed associations between species formerly classified in distinct tribes within the family Cracidae. The basal position of cracids to the rest of the Galloanserae was confirmed. Estimated ages of divergence from common ancestors are consistent with fossil evidence for most of the lineages examined although...
Biodiversity, Oct 30, 2014
Globally, arid lands are under increasing pressure from growing populations and anthropogenic dis... more Globally, arid lands are under increasing pressure from growing populations and anthropogenic disturbance from resource extraction, water diversion, introduced species, pollution and inadequate management for long-term sustainability. Biodiversity in dry regions, already at the physiological and energy limits for survival, may be particularly threatened by disturbance and the complex effects of climate change. Arid environments harbour unique endemic species and evolutionary novelty, and must be considered as conservation priorities. Here the cold arid lands of South America are highlighted, with examples of unique lineages and brief overviews of emerging issues threatening these ecosystems.
Journal of Avian Biology, May 3, 2011
Many seabirds exhibit high natal philopatry despite their extreme dispersal ability and delayed r... more Many seabirds exhibit high natal philopatry despite their extreme dispersal ability and delayed reproduction, and some exhibit phenotypic clustering in colonies and fostering or adoption of neighbouring chicks. Previous investigations of kinship in a small thick-billed murre colony Uria lomvia (Alcidae) in Norway revealed high relatedness among breeders on cliff ledges. To investigate the presence of kin groups and within-colony genetic sub-structuring elsewhere, we investigated kinship within a larger murre colony on Coats Island, Nunavut, Canada. Morphological (five characters) and genetic data (five microsatellite loci and a fragment of the mitochondrial cytochrome b gene) were analysed. Strong morphological differentiation was found among ledges. Genetic structuring was overall weak but significant at the coarse scale for males among ledges and on the east vs. the west side of the colony. Global spatial autocorrelation analyses did not detect consistent, widespread spatial patterns, although local 2D analyses provided some evidence of a tendency for larger neighbourhood sizes for females and a broad range of small to large neighbourhoods for males. Average within-ledge relatedness was low overall, but ranged widely from slightly unrelated to greater than the level of cousins in both sexes. Kin-level relationships occurred on ledges more frequently for same-sex groups than expected by chance, suggesting that recruiting breeders (especially females) avoid or are unable to settle directly adjacent to relatives particularly of the opposite sex. Behavioural studies of natal dispersal of murres at Coats I. indicating that both sexes are highly philopatric, but that up to one-fifth of females may disperse, are concordant with this study. Overall, structuring was weaker than in Norway, and may be explained in part by genetic marker and sampling artifacts, and by the lack of genetic equilibrium suspected in the much larger Canadian Arctic colony. Natal philopatry may be an important factor driving the diversification of seabirds and kin groups in other colonies and species and may be more widespread than is currently acknowledged.
Genome, 2006
Mitochondrial DNA (mtDNA) continues to play a pivotal role in phylogeographic, phylogenetic, and ... more Mitochondrial DNA (mtDNA) continues to play a pivotal role in phylogeographic, phylogenetic, and population genetic studies. PCR amplification with mitochondrial primers often yields ambiguous sequences, in part because of the coamplification of nuclear copies of mitochondrial genes (numts) and true mitochondrial heteroplasmy arising from mutations, hybridization with paternal leakage, gene duplications, and recombination. Failing to detect numts or to distinguish the origin of such homologous sequences results in the incorrect interpretation of data. However, few studies obtain purified mtDNA to confirm the mitochondrial origin of the first reference sequences for a species. Here, we demonstrate the importance and ease of obtaining semi-pure mtDNA from wildlife tissues, preserved under various typical field conditions, and investigate the success of 3 commercial extraction kits, cesium-chloride gradient mtDNA purification, long-template PCR amplification, cloning, and more species-specific degenerate primers. Using more detailed avian examples, we illustrate that unfertilized or undeveloped eggs provide the purest sources of mtDNA; that kits provide an alternative to cesium-chloride gradient methods; and that long-template PCR, cloning, and degenerate primers cannot be used to produce reliable mitochondrial reference sequences, but can be powerful tools when used in conjunction with purified mtDNA stocks to distinguish numts from true heteroplasmy.
Journal of Heredity, 2004
The widespread utility of hypervariable loci in genetic studies derives from the high mutation ra... more The widespread utility of hypervariable loci in genetic studies derives from the high mutation rate, and thus the high polymorphism, of these loci. Recent evidence suggests that mutation rates can be extremely high and may be male biased (occurring in the male germ-line). These two factors combined may result in erroneous overestimates of extrapair paternity, since legitimate offspring with novel alleles will have more mismatches with respect to the biological father than the biological mother. As mutations are male driven, increasing the number of hypervariable loci screened may simply increase the number of mismatches between fathers and their legitimate offspring. Here we describe a simple statistic, the probability of resemblance (P R ), to distinguish between mismatches due to parental misassignment versus mutation in either sex or null alleles. We apply this method to parentage data on thick-billed murres (Uria lomvia), and demonstrate that, without considering either mutations or male-biased mutation rates, cases of extrapair paternity (7% in this study) would be grossly overestimated (14.5%-22%). The probability of resemblance can be utilized in parentage studies of any sexually reproducing species when allele or haplotype frequency data are available for putative parents and offspring. We suggest calculating this probability to correctly categorize legitimate offspring when mutations and null alleles may cause mismatches.
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Papers by Gabriela Ibarguchi