scholarly journals Conservation Genetic Assessment of Savannah Elephants (Loxodonta africana) in the Greater Kruger Biosphere, South Africa

Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 779
Author(s):  
Santos ◽  
Fernandes ◽  
Henley ◽  
Dawson ◽  
Mumby
Keyword(s):  
Population Size ◽  
National Park ◽  
Genetic Bottleneck ◽  
Kruger National Park ◽  
Time Lags ◽  
Limited Information ◽  
Effective Population ◽  
Evolutionary Potential ◽  
Starting Point ◽  
Demographic Bottleneck

Savannah elephant populations have been severely reduced and fragmented throughout its remaining range. In general, however, there is limited information regarding their genetic status, which is essential knowledge for conservation. We investigated patterns of genetic variation in savannah elephants from the Greater Kruger Biosphere, with a focus on those in previously unstudied nature reserves adjacent to Kruger National Park, using dung samples from 294 individuals and 18 microsatellites. The results of genetic structure analyses using several different methods of ordination and Bayesian clustering strongly suggest that elephants throughout the Greater Kruger National Park (GKNP) constitute a single population. No evidence of a recent genetic bottleneck was detected using three moment-based approaches and two coalescent likelihood methods. The apparent absence of a recent genetic bottleneck associated with the known early 1900s demographic bottleneck may result from a combination of rapid post-bottleneck population growth, immigration and long generation time. Point estimates of contemporary effective population size (Ne) for the GKNP were ~ 500–700, that is, at the low end of the range of Ne values that have been proposed for maintaining evolutionary potential and the current ratio of Ne to census population size (Nc) may be quite low (<0.1). This study illustrates the difficulties in assessing the impacts on Ne in populations that have suffered demographic crashes but have recovered rapidly and received gene flow, particularly in species with long generation times in which genetic time lags are longer. This work provides a starting point and baseline information for genetic monitoring of the GKNP elephants.

scholarly journals The paradox of retained genetic diversity of Hippocampus guttulatus in the face of demographic decline

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rupert Stacy ◽  
Jorge Palma ◽  
Miguel Correia ◽  
Anthony B. Wilson ◽  
José Pedro Andrade ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Population Size ◽  
Effective Population Size ◽  
Population Decline ◽  
Genetic Bottleneck ◽  
Effective Population ◽  
Evolutionary Potential ◽  
Hippocampus Guttulatus ◽  
Ria Formosa

AbstractGenetic diversity is the raw foundation for evolutionary potential. When genetic diversity is significantly reduced, the risk of extinction is heightened considerably. The long-snouted seahorse (Hippocampus guttulatus) is one of two seahorse species occurring in the North-East Atlantic. The population living in the Ria Formosa (South Portugal) declined dramatically between 2001 and 2008, prompting fears of greatly reduced genetic diversity and reduced effective population size, hallmarks of a genetic bottleneck. This study tests these hypotheses using samples from eight microsatellite loci taken from 2001 and 2013, on either side of the 2008 decline. The data suggest that the population has not lost its genetic diversity, and a genetic bottleneck was not detectable. However, overall relatedness increased between 2001 to 2013, leading to questions of future inbreeding. The effective population size has seemingly increased close to the threshold necessary for the population to retain its evolutionary potential, but whether these results have been affected by sample size is not clear. Several explanations are discussed for these unexpected results, such as gene flow, local decline due to dispersal to other areas of the Ria Formosa, and the potential that the duration of the demographic decline too short to record changes in the genetic diversity. Given the results presented here and recent evidence of a second population decline, the precise estimation of both gene flow and effective population size via more extensive genetic screening will be critical to effective population management.

scholarly journals The dynamics of questing ticks collected for 164 consecutive months off the vegetation of two landscape zones in the Kruger National Park (1988–2002). Part III. The less commonly collected species

2011 ◽  
Vol 78 (1) ◽  
Author(s):  
Gordon J. Gallivan ◽  
Andrea Spickett ◽  
Heloise Heyne ◽  
Arthur M. Spickett ◽  
Ivan G. Horak
Keyword(s):  
National Park ◽  
Development Stage ◽  
Kruger National Park ◽  
Ixodid Ticks ◽  
Limited Information ◽  
Host Seeking ◽  
Haemaphysalis Elliptica ◽  
Questing Ticks ◽  
Landscape Zone

Despite many studies regarding tick ecology, limited information on long-term changes in tick populations exist. This study assessed the long-term population dynamics of the less frequently collected questing ixodid ticks in the Kruger National Park (KNP). From 1988 to 2002, monthly dragging of the vegetation was performed in three habitats (grassland, woodland and gully) at two sites in the KNP (Nhlowa Road, Landscape Zone 17, and Skukuza, Landscape Zone 4). Amblyomma marmoreum and Rhipicephalus evertsi evertsi were collected as larvae most commonly. Most A. marmoreum larvae were collected at Skukuza and numbers peaked from March to July. More R. evertsi evertsi larvae were collected at Nhlowa Road and numbers peaked in summer and in winter, while at Skukuza there was a single peak in spring. Haemaphysalis elliptica, Rhipicephalus simus and Rhipicephalus turanicus were collected as adults most commonly. More Ha. elliptica and R. turanicus were collected at Nhlowa Road than at Skukuza, while R. simus numbers from the two sites were approximately equal. Ha. elliptica were collected most often between February and June, and R. simus and R. turanicus during February and March. All three species were collected more frequently in gullies than in grassland or woodland. Their numbers increased in 1994/1995 following an eruption of rodents, the preferred hosts of the immature stages. The different host-seeking strategies of ticks largely determine the development stage at which they are likely to be collected during vegetation dragging and reflect a complex interaction between ticks, their hosts and the environment.

scholarly journals In with the Old, in with the New: The Promiscuity of the Duplication Process Engenders Diverse Pathways for Novel Gene Creation

2012 ◽  
Vol 2012 ◽  
pp. 1-24 ◽  
Author(s):  
Vaishali Katju
Keyword(s):  
Gene Duplication ◽  
Population Size ◽  
Population Genetic ◽  
Effective Population ◽  
Evolutionary Potential ◽  
Dna And Rna ◽  
Duplication Events ◽  
History Of ◽  
Theoretical Population ◽  
Novel Exon

The gene duplication process has exhibited far greater promiscuity in the creation of paralogs with novel exon-intron structures than anticipated even by Ohno. In this paper I explore the history of the field, from the neo-Darwinian synthesis through Ohno’s formulation of the canonical model for the evolution of gene duplicates and culminating in the present genomic era. I delineate the major tenets of Ohno’s model and discuss its failure to encapsulate the full complexity of the duplication process as revealed in the era of genomics. I discuss the diverse classes of paralogs originating from both DNA- and RNA-mediated duplication events and their evolutionary potential for assuming radically altered functions, as well as the degree to which they can function unconstrained from the pressure of gene conversion. Lastly, I explore theoretical population-genetic considerations of how the effective population size (Ne) of a species may influence the probability of emergence of genes with radically altered functions.

scholarly journals Genetic Resilience of a Once Endangered Species, Tibetan Antelope (Pantholops hodgsonii)

2019 ◽  
Author(s):  
Yue Shi ◽  
Jiarui Chen ◽  
Jianping Su ◽  
Tongzuo Zhang ◽  
Samuel K. Wasser
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Population Size ◽  
Effective Population Size ◽  
Genetic Bottleneck ◽  
Migration Routes ◽  
Effective Population ◽  
Human Disturbances ◽  
Population Reduction ◽  
Tibetan Antelope

AbstractPopulation reduction is generally assumed to reduce the population’s genetic diversity and hence its ability to adapt to environmental change. However, if life history traits that promote gene flow buffer populations from such impacts, conservation efforts should aim to maintain those traits in vulnerable species. Tibetan antelope (Pantholops hodgsonii) has experienced population reduction by 95% due to poaching during the 20th century. We hypothesize that opportunities for gene flow provided by their sex-specific migration buffered their genetic diversity from the poaching impacts. We measured the mtDNA (control region, CR) and nuDNA (microsatellites or STRs) diversity, population differentiation, along with the change in effective population size (pre-poaching era vs. post-poaching era) and tested for a genetic bottleneck. Our results showed that Tibetan antelope maintained considerable genetic diversity in both mtDNA CR and STR markers (Hd = 0.9970 and Hobs = 0.8446, respectively), despite a marked reduction in post-poaching effective population size 368.9 (95% CI of 249.3 - 660.6) compared to the pre-poaching average (4.93×103 - 4.17×104). Post-poached populations also had low population structure and showed no evidence of a genetic bottleneck. Pairwise Fst values using CR haplotype frequencies were higher than those using STR allele frequencies, suggesting different degrees of gene flow mediated by females and males. This study suggests that the Tibetan antelope’s sex-specific migration buffered their loss of genetic diversity in the face of severe demographic decline. These findings highlight the importance of recognizing the traits likely to maintain genetic diversity and promoting conservation efforts that allow them to be exercised. For Tibetan antelope, this requires assuring that their migration routes remain unobstructed by growing human disturbances while continuing to enforce anti-poaching law enforcement efforts.

scholarly journals A checklist of the termites of Kruger National Park, South Africa

Koedoe ◽  
2019 ◽  
Vol 61 (1) ◽  
Author(s):  
Brianna M. Lind ◽  
Andrew B. Davies
Keyword(s):  
National Park ◽  
Kruger National Park ◽  
Future Research ◽  
Central Component ◽  
Conservation Areas ◽  
Conservation Implications ◽  
Starting Point ◽  
Species Checklist ◽  
Water Redistribution ◽  
Original Survey

The protection of biodiversity is critical to ecosystem function and is a primary management goal for conservation areas globally. Maintaining a current inventory of known diversity is a central component of achieving this goal and serves as an essential starting point for future research endeavours. Since the first published survey of termites in South Africa’s Kruger National Park (KNP) over 55 years ago, our understanding of termite diversity has expanded sufficiently to merit an update and formal checklist. Here we revise the inventory of termite diversity in KNP and summarise the taxonomic and functional diversity of termites in the park. A thorough review of recent termite research in KNP added 6 new genera and 13 species to what was found in Coaton’s original survey, with one genus, Anenteotermes, recorded for the first time in southern Africa. Based on the updated species checklist, the majority of genera in the park belong to Feeding Group II (39%) and the Termitidae family (75%).Conservation implications: In savannas, termites play crucial roles in nutrient cycling, water redistribution and plant dynamics. Systematically cataloguing termite diversity and assemblage composition in the park provides an essential baseline for scientific research, aids biodiversity conservation efforts and encourages scientists and managers to consider termites in ecosystem functioning and management. Having more detailed descriptions of genera, species and feeding groups allows for more tangible, ecologically relevant attributions of termite influence, facilitates enhanced inquiry and allows for more realistic quantification of termite roles in key ecosystem processes.

The Role of Dispersal in Structuring the Chitwan Tiger Population

Behaviour ◽  
1993 ◽  
Vol 124 (3-4) ◽  
pp. 165-195 ◽  
Author(s):  
JAMES L. DAVID Smith
Keyword(s):  
Social Interactions ◽  
Population Size ◽  
National Park ◽  
Genetic Variance ◽  
Effective Population ◽  
The World ◽  
Chitwan National Park ◽  
Tiger Population ◽  
Stochastic Events

AbstractDispersal in tigers was studied in Royal Chitwan National Park, Nepal. Thirty six adult and young were studied to monitor movements and social interactions relative to dispersal. Fourteen subadults were followed from before their dispersal until they died or established post-dispersal territories. Subadult tigers became semi-independent of their mother when her next litter was born. They usually remained within her natal area until the subsequent litter began to move with her at about 2 mos of age. Animals dispersed between 19 and 28 mos. Males dispersed farther than females and settled in poorer habitat. Three of 4 females settled adjacent to their mothers; in two cases the mother shifted her territory allowing the daughter to take over a large portion of the mother's former territory. Wounds on young prior to dispersal indicated that aggression prompted dispersal. Fjghts were observed between dispersers and residents. After fights, dispersers always left the resident's area. All 4 dispersing females established breeding territories. Females settled next to their mothers tending to reduce the genetic variance of a male's offspring. Eight of 10 males became localized in temporary, post-dispersal territories; 4 of the 8 survived. Two males died of poisoning and 2 from intrasexual aggression. Surviving males either expanded temporary territories or shifted to new areas to establish breeding territories. The Chitwan tigers are an isolated remnant of a population once continuous across the lowlands of Nepal. Effective population size was estimated to be <30 animals. Tigers did not disperse across cultivated areas but did travel through degraded forest habitat. No animal dispersed outside the Chitwan region and there appear to be effective barriers separating Chitwan from the two nearest populations 150 and 250 kms distant. The Chitwan population is probably one of the largest tiger populations remaining in the world. Isolation and small size threaten these populations with stochastic events that may lead to further reduction in population size.

scholarly journals Evidence for an extreme founding effect in a highly successful invasive species

2020 ◽  
Author(s):  
Kateryna V. Kratzer ◽  
Annemarie van der Marel ◽  
Colin Garroway ◽  
Marta López-Darias ◽  
Stephen D. Petersen ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Invasive Species ◽  
Population Size ◽  
Genetic Bottleneck ◽  
Ground Squirrels ◽  
Invasion Success ◽  
Island Population ◽  
Effective Population ◽  
Founding Population ◽  
Mitochondrial Haplotypes

AbstractThe adaptive potential of invasive species is thought to decrease during founding events due to reduced genetic diversity, limiting the new population’s ability to colonize novel habitats. Barbary ground squirrels (Atlantoxerus getulus) were purportedly introduced as a single breeding pair to the island of Fuerteventura but have expanded to over a million individuals spread across the island in just over 50 years. We estimated the number of founders and measured the level of genetic diversity in this population using the mitochondrial displacement loop and microsatellite markers. Island samples (n = 19) showed no variation in the d-loop, suggesting a single founding female, while Moroccan samples (n = 6) each had unique mitochondrial haplotypes. The microsatellite data of the island population (n = 256 individuals) revealed a small effective population size, low levels of heterozygosity, and high levels of inbreeding, supporting a founding population size of two to three individuals. Our results suggest that A. getulus has undergone an intense genetic bottleneck during their colonization of the island. They are one of the few species where introduction effort does not explain invasion success, although further investigation may explain how they have avoided the worst expected effects following an extreme genetic bottleneck.

scholarly journals The dynamics of questing ticks collected for 164 consecutive months off the vegetation of two landscape zones in the Kruger National Park (1988–2002). Part I. Total ticks, Amblyomma hebraeum and Rhipicephalus decoloratus

2011 ◽  
Vol 78 (1) ◽  
Author(s):  
Ivan G. Horak ◽  
Gordon J. Gallivan ◽  
Arthur M. Spickett
Keyword(s):  
Population Dynamics ◽  
Tick Species ◽  
National Park ◽  
Kruger National Park ◽  
Ixodid Ticks ◽  
Limited Information ◽  
Amblyomma Hebraeum ◽  
Generic Level ◽  
Questing Ticks

Despite a large number of studies on tick biology, there is limited information on long- term changes in tick populations. This study thus aimed to assess the long-term population dynamics of questing ixodid ticks in two landscape zones of the Kruger National Park (KNP). Questing ixodid ticks were collected in the KNP from August 1988 to March 2002 by monthly dragging of the vegetation in three habitats (grassland, woodland and gully) at two sites (Nhlowa Road and Skukuza). Findings pertaining to total tick numbers and Amblyomma hebraeum and Rhipicephalus decoloratus specifically are presented here. Fourteen tick species were collected, as well as four others that could be identified only to generic level. More ticks (211 569 vs 125 810) were collected at Nhlowa Road than at Skukuza. Larvae were the most commonly collected stage of all the major tick species. A. hebraeum was the most commonly collected tick (63.6%) at Nhlowa Road, whereas R. decoloratus accounted for 15.3% of the ticks collected there. At Skukuza, 31.6% and 27.1% of the collected ticks were R. decoloratus and A. hebraeum respectively. Most A. hebraeum larvae were collected in summer and the fewest in winter and early spring, mostly in woodland and least often in grassland habitats. Most R. decoloratus larvae were collected in spring and the fewest in autumn and winter, and were more frequently collected in woodland and grassland than in gullies. The largest collections of most tick species were made during the early 1990s, while numbers were lowest in the mid-1990s after a drought during 1991 and 1992 and then increased towards the late 1990s, followed by a final decrease. The changes in tick numbers over time probably reflect differences in their host communities at the two sites and the effect of climatic conditions on both hosts and free-living ticks. The population dynamics of questing ticks reflect a complex interaction between ticks, their hosts and the environment.

scholarly journals Monitoring methods and techniques for censusing black rhinoceros Diceros bicomis bicomis in Etosha National Park

Koedoe ◽  
1989 ◽  
Vol 32 (2) ◽  
Author(s):  
A. Cilliers
Keyword(s):  
Population Size ◽  
National Park ◽  
Kruger National Park ◽  
Monitoring Methods ◽  
Black Rhinoceros ◽  
Population Size Estimates ◽  
Species Population ◽  
Census Techniques ◽  
Size Estimates ◽  
Size And Structure

Selected Papers from the Rhinoceros Conservation Workshop, Skukuza, Kruger National Park,31 August – 4 September 1988 Water-hole census techniques as developed in Etosha for monitoring black rhinoceros are described in detail. The systematic recording of animals visiting water-holes at night yielded data on the population size and structure, and frequency of drinking of this species. Population size estimates derived from this method were compared with estimates derived from aerial census techniques. It was concluded that censusing at a water-hole accounted for 32 percent more animals than a total aerial count by helicopter, and 70 percent more animals than by using a fixed- wing aircraft.

Sign in / Sign up

Export Citation Format

Share Document