Grewcock Center for Conservation and Research

South Sioux City, NE, United States

Grewcock Center for Conservation and Research

South Sioux City, NE, United States

Time filter

Source Type

Lei R.,Grewcock Center for Conservation and Research | Frasier C.L.,Grewcock Center for Conservation and Research | Hawkins M.T.R.,Grewcock Center for Conservation and Research | Engberg S.E.,Grewcock Center for Conservation and Research | And 8 more authors.
Journal of Heredity | Year: 2017

The family Lepilemuridae includes 26 species of sportive lemurs, most of which were recently described. The cryptic morphological differences confounded taxonomy until recent molecular studies; however, some species' boundaries remain uncertain. To better understand the genus Lepilemur, we analyzed 35 complete mitochondrial genomes representing all recognized 26 sportive lemur taxa and estimated divergence dates. With our dataset we recovered 25 reciprocally monophyletic lineages, as well as an admixed clade containing Lepilemur mittermeieri and Lepilemur dorsalis. Using modern distribution data, an ancestral area reconstruction and an ecological vicariance analysis were performed to trace the history of diversification and to test biogeographic hypotheses. We estimated the initial split between the eastern and western Lepilemur clades to have occurred in the Miocene. Divergence of most species occurred from the Pliocene to the Pleistocene. The biogeographic patterns recovered in this study were better addressed with a combinatorial approach including climate, watersheds, and rivers. Generally, current climate and watershed hypotheses performed better for western and eastern clades, while speciation of northern clades was not adequately supported using the ecological factors incorporated in this study. Thus, multiple mechanisms likely contributed to the speciation and distribution patterns in Lepilemur. © The American Genetic Association 2016. All rights reserved.


Brenneman R.A.,Grewcock Center for Conservation and Research | Johnson S.E.,University of Calgary | Bailey C.A.,Grewcock Center for Conservation and Research | Ingraldi C.,University of Calgary | And 6 more authors.
ORYX | Year: 2012

Knowledge of both population size and genetic diversity is critical for assessing extinction risk but few studies include concurrent estimates of these two components of population biology. We conducted an investigation of population density and size, and genetic variation and past demographic events, of the Endangered grey-headed lemur Eulemur cinereiceps in south-east Madagascar. We estimated lemur density using line-transect surveys and used satellite imagery to calculate forest fragment area in three localities. We collected tissue samples from 53 individuals and used 26 polymorphic microsatellite loci to obtain measures of population structure (divergence and diversity) across these localities. We tested the probability of past bottleneck events using three models. Contrary to expectation, there were no significant differences in population density across localities. Genetic diversity decreased, but not significantly, with decreasing habitat area and population size. We found a higher likelihood of past bottleneck events in the fragmented coastal populations. The low population size and prior decline in diversity in coastal patches are consistent with their isolation, anthropogenic disturbance, and exposure to cyclone activity. The similarities in the estimates of density between continuous and fragmented sites may indicate recent population growth in the fragments but these populations nevertheless remain at risk from reduced levels of genetic variation. These patterns should be confirmed with more extensive sampling across the limited range of E. cinereiceps. © 2011 Fauna & Flora International.


Lei R.,Grewcock Center for Conservation and Research | Brenneman R.A.,Grewcock Center for Conservation and Research | Schmitt D.L.,Missouri State University | Schmitt D.L.,Ringling Bros Center For Elephant Conservation | Louis E.E.,Grewcock Center for Conservation and Research
Journal of Zoology | Year: 2012

To assess genetic diversity in North American captive Asian elephants Elephas maximus, one mitochondrial DNA (mtDNA) segment was sequenced in combination with multilocus genotypes generated from 20 nuclear microsatellite loci for 201 individuals. The analysis of 627bp of the C-terminal of cyt b and the hypervariable left domain of the noncoding control region (labeled as MDL fragment) sequences revealed the existence of two mtDNA lineages (α and β clade). Analysis of the MDL confirmed that North American captive Asian elephants belong to either the previously characterized α or β clade. An average nucleotide diversity of 0.017 was observed for the Asian elephant mtDNA MDL fragment sequences. Regardless whether an individual possessed mtDNA α or β clade haplotype, all individuals belonged to one nuclear gene lineage for the two X-linked (BGN and PHKA2) and one Y-linked (AMELY) genes sequenced. Analysis of multilocus genotypes indicated an average observed and expected heterozygosities were 0.543 and 0.539 in wild-sourced and 0.579 and 0.547 in the captive-born Asian elephants, respectively. No subdivision among the sampled individuals was detected, including data partitioned by mtDNA clades. Aside from parent-offspring dyads, no further relationships were detected among wild-sourced and captive-born Asian elephants (average relatedness value <0.000). © 2011 The Authors. Journal of Zoology © 2011 The Zoological Society of London.


Brenneman R.A.,Giraffe Conservation Foundation | McLain A.T.,New York University | Taylor J.M.,Grewcock Center for Conservation and Research | Zaonarivelo J.R.,Grewcock Center for Conservation and Research | And 8 more authors.
International Journal of Primatology | Year: 2016

Subspecies were traditionally defined by identifying gaps between phenotypes across the geographic range of a species, and may represent important units in the development of conservation strategies focused on preserving genetic diversity. Previous taxonomic research proposed that phenotypic variation between scattered Indri indri populations warranted the naming of two distinct subspecies, I. i. indri and I. i. variegatus. We tested these subspecific designations using mitochondrial sequence data generated from the control region or D-loop (569 bp) and a large section (2362 bp) of multiple genes and tRNAs known as Pastorini’s fragment and nuclear microsatellite markers. This study used 114 samples of I. indri from 12 rainforest sites in eastern Madagascar, encompassing the entire range of the species. These genetic samples represent multiple populations from low- and high-elevation forests from both putative subspecies. Molecular analyses of the mitochondrial sequence data did not support the two proposed subspecies. Furthermore, the microsatellite analyses showed no significant differences across the range beyond population level differentiation. This study demonstrates the utility of incorporating multiple lines of evidence in addition to phenotypic traits to define species or subspecies. © 2016, Springer Science+Business Media New York.


Fennessy J.,Giraffe Conservation Foundation | Bock F.,Biodiversity and Climate Research Center | Tutchings A.,Giraffe Conservation Foundation | Brenneman R.,Giraffe Conservation Foundation | And 3 more authors.
African Journal of Ecology | Year: 2013

Thornicroft's giraffe, Giraffa camelopardalis thornicrofti, is a geographically isolated subspecies of giraffe found only in north-east Zambia. The population only occurs in Zambia's South Luangwa Valley, an area which interestingly places it between the current distribution of Masai (G. c. tippelskirchi) giraffe to the north, and the Angolan (G. c. angolensis) and South African (G. c. giraffa) giraffe in the south-west and south, respectively. Specific studies have been undertaken on the ecology of this subspecies, but their population genetics remains unknown. We studied 34 individuals from the South Luangwa National Park and adjacent Lupande Game Management Area and seven individuals from northern Botswana. The complete cytochrome b and control region sequences of the mitochondrial genome were sequenced and analysed together with database data by maximum likelihood tree reconstruction and maximum parsimony network analyses. The giraffe from Zambia's South Luangwa Valley are most closely related to the subspecies G. c. tippelskirchi and part of their radiation. However, they form a unique population that would benefit from increased research and conservation management. © 2013 John Wiley & Sons Ltd.


Holmes S.M.,University of Calgary | Gordon A.D.,University at Albany | Louis E.E.,Grewcock Center for Conservation and Research | Johnson S.E.,University of Calgary
Behavioral Ecology and Sociobiology | Year: 2016

Abstract: Species with greater expression of fission-fusion dynamics show greater variability in the size, composition, and cohesion of subgroups over time. This may allow their adjustment to local environmental, social, and demographic conditions. We tested which environmental and social factors influenced subgroup size in one such species, the black-and-white ruffed lemur (Varecia variegata) at two sites within a fragmented forest landscape. Using instantaneous focal sampling at 15-min intervals, we collected data on subgroup size and composition, fruit and flower availability, and location. We also collected biweekly data on site-wide fruit and flower availability. We used these data to test the influence of season, food availability, reproduction, and predation risk on adult subgroup size in this species. Ruffed lemur adults consistently formed significantly larger subgroups in times of lower site-wide fruit availability, during the wet season, and when one or more infants were present. There were differences between sites in the relationship between subgroup size and tree size, fruit patch size, and site-wide flower availability. Variables measuring indirect predation risk showed no significant relationship with subgroup size. These results emphasize the strong relationship between fission-fusion dynamics and spatial and temporal variation in food availability, as well as the importance of sociality in a species with communal care of infants. Fission-fusion dynamics may serve as an evolutionary strategy to adapt to the unpredictable and sometimes harsh environmental conditions of Madagascar and may facilitate the persistence of communities of this critically endangered lemur despite widespread anthropogenic habitat modification. Significance statement: Fission-fusion dynamics (the joining and separating of subgroups within a larger group of animals) may allow species to adjust social benefits to changing environmental conditions. This study examines the underlying ecological and social factors that might influence fission-fusion dynamics in black-and-white ruffed lemurs. Subgroup size in this species was strongly related to food availability, though not always in the direction expected. This suggests that the relationship between food availability and sociality changes when food availability reaches very low levels. Additionally, infant presence was linked to larger adult subgroups, indicating a connection between fission-fusion behavior and the cooperative rearing of offspring seen in this species. Relationships between subgroup size and some environmental variables differed between sites, emphasizing the flexibility of grouping patterns in this species and indicating that local conditions may play a large role in the expression of fission-fusion dynamics. © 2016 Springer-Verlag Berlin Heidelberg


Fourie J.,University of Pretoria | Loskutoff N.,Grewcock Center for Conservation and Research | Huyser C.,University of Pretoria
Journal of Assisted Reproduction and Genetics | Year: 2012

Purpose: Seminal pathogens can bind specifically or non-specifically to spermatozoa, rendering semen decontamination procedures ineffective, whereby vertical or horizontal transmission of the infection could occur. Serine proteases have been demonstrated to effectively inactivate viruses and to break pathogen-sperm bonds. However, the addition of a protease to density gradient layers during semen processing could negatively impact on sperm parameters. This study investigated the effect of the addition of a recombinant, human-sequence protease (rhProtease) on sperm parameters during density gradient centrifugation. Methods: (i) Pooled semen samples (n = 9) were split and processed by density gradient centrifugation, with the top density layers supplemented, or non-supplemented with rhProtease at three different concentrations (diluted 2, 10 and 20 times). Sperm parameters were then analysed by flow cytometry and computer-assisted semen analyses. (ii) Semen samples (n = 5) were split and similarly processed using PureSperm® Pro, with rhProtease in the 40 % density gradient layer, or standard PureSperm® not supplemented with rhProtease (Nidacon, International) respectively. The Hemizona assay was then utilized to compare sperm-zona binding post processing. Results: Evaluation of sperm parameters indicated that rhProtease did not, at any of the tested concentrations, have an impact on (i) mitochondrial membrane potential, vitality, motility, or (ii) zona binding potential. Conclusion: We report that the addition of rhProtease to density gradients is a non-detrimental approach that could improve the effectiveness of semen processing for the elimination of seminal pathogens, and benefit assisted reproduction outcome. © 2012 Springer Science+Business Media, LLC.


Tabora J.A.G.,University of Southern Mindanao | Hinlo M.R.P.,Massey University | Bailey C.A.,Grewcock Center for Conservation and Research | Lei R.,Grewcock Center for Conservation and Research | And 7 more authors.
Zootaxa | Year: 2012

The Philippine crocodile (Crocodylus mindorensis) is considered one of the most endangered of the crocodilian species. Rumors or anecdotal concerns have existed for some time as to the possibility of hybrid individuals existing in a captive collection under consideration for providing reintroduction candidates; however, visual observations failed to identify sus-pected hybrids. Samples were collected from 619 Philippine crocodiles from several captive facilities and two free-rang-ing populations. Mitochondrial DNA D-loop (601 bp) fragments were sequenced for each crocodile and compared to 28 individuals representing ten crocodile species. Among Philippine crocodiles, 48 variable sites (47 parsimony informative sites) were identified, which defined six C. mindorensis haplotypes and one C. porosus-derived haplotype. Data were also generated for a 965 bp fragment of the ND4 subunit gene fragment for two samples of each D-loop haplotype. Among them, 91 variable sites (90 parsimony informative site) were identified, which defined three C. mindorensis haplotypes and one C. porosus-derived haplotype. From the nuclear genome, the C-mos gene was successfully amplified for the 388 bp partial fragment for all Philippine crocodile samples. Only two variable sites were identified. These sequences were compared to GenBank sequences for C. porosus. Of the 619 Philippine crocodile samples, 57 samples were found to har-bor D-loop haplotypes identified as C. porosus and 31 of those harbored C-mos mutational sites diagnostic for C. porosus introgression. All individuals indicating C. mindorensis x C. porosus hybridization were sampled from the Palawan Wild-life Rescue and Conservation Center. Copyright © 2012 Magnolia Press.


Rakotoarisoa J.-E.,Yale University | Rakotoarisoa J.-E.,Illinois State University | Bailey C.A.,Grewcock Center for Conservation and Research | Hinger P.H.,Grewcock Center for Conservation and Research | And 2 more authors.
Conservation Genetics Resources | Year: 2013

We developed microsatellite markers for the recently described forest rodent, Eliurus carletoni, from an enriched genomic library. Nine loci composed of four dinucleotide, one trinucleotide, one tetranucleotide and three compound repeats were isolated and characterized using two wild populations. One locus was found to be monomorphic. For the polymorphic loci, the average number of alleles per locus was 7. 13 and 8. 38 for each population. Mean expected and observed heterozygosities were high (i. e. 0. 76 and 0. 80). Tests for linkage disequilibrium were not significant across all locus pairs. One locus tested significant for null alleles, but only one population exhibited a significant deviation from the Hardy-Weinberg Equilibrium (HWE) at this locus. All remaining loci show no evidence of departure from HWE. Overall, we identified eight polymorphic loci that may be used in conservation and population genetics studies of E. carletoni. © 2012 Springer Science+Business Media B.V.


Holmes S.M.,University of Calgary | Baden A.L.,Yale University | Brenneman R.A.,Grewcock Center for Conservation and Research | Engberg S.E.,Grewcock Center for Conservation and Research | And 2 more authors.
Conservation Genetics | Year: 2013

Land use in Madagascar has resulted in extensive deforestation and forest fragmentation. Endemic species, such as the black-and-white ruffed lemur (Varecia variegata), may be vulnerable to habitat fragmentation due to patchy geographic distributions and sensitivities to forest disturbance. We tested for genetic differentiation among black-and-white ruffed lemur groups in two sites in a large forest patch and three sites in smaller patches. We also investigated the relationship between the genetic diversity of populations and patch configuration (size and isolation), as well as the presence or absence of past genetic bottlenecks. We collected blood (n = 22 individuals) or fecal (n = 33) samples from lemurs and genotyped the extracted DNA for 16 polymorphic microsatellites. Bayesian cluster analysis and FST assigned individuals to three populations: Ranomafana (two sites in continuous forest), Kianjavato (two fragments separated by 60 m of non-forest), and Vatovavy (a single fragment, more isolated in time and space). Vatovavy showed significantly lower allelic richness than Ranomafana. Kianjavato also appeared to have lower allelic richness than Ranomafana, though the difference was not significant. Vatovavy was also the only population with a genetic bottleneck indicated under more than one mutation model and a significant FIS value, showing excess heterozygosity. These results indicate that a small geographic separation may not be sufficient for genetic differentiation of black-and-white ruffed lemur populations and that patch size may influence the rapidity with which genetic diversity is lost following patch isolation. © 2013 Springer Science+Business Media Dordrecht.

Loading Grewcock Center for Conservation and Research collaborators
Loading Grewcock Center for Conservation and Research collaborators