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 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 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 II. Rhipicephalus appendiculatus and Rhipicephalus zambeziensis

2011 ◽  
Vol 78 (1) ◽  
Author(s):  
Arthur M. Spickett ◽  
Gordon J. Gallivan ◽  
Ivan G. Horak
Keyword(s):  
Population Dynamics ◽  
Relative Humidity ◽  
National Park ◽  
Rhipicephalus Appendiculatus ◽  
Kruger National Park ◽  
Large Herbivore ◽  
Questing Ticks ◽  
Over Time

The study aimed to assess the long-term population dynamics of questing Rhipicephalus appendiculatus and Rhipicephalus zambeziensis in two landscape zones of the Kruger National Park (KNP). Ticks were collected by dragging the vegetation monthly in three habitats (grassland, woodland and gully) at two sites in the KNP (Nhlowa Road and Skukuza) from August 1988 to March 2002. Larvae were the most commonly collected stage of both species. More R. appendiculatus were collected at Nhlowa Road than at Skukuza, with larvae being most abundant from May to August, while nymphs were most abundant from August to December. Larvae were most commonly collected in the gullies from 1991 to 1994, but in the grassland and woodland habitats from 1998 onwards. Nymphs were most commonly collected in the grassland and woodland. More R. zambeziensis were collected at Skukuza than at Nhlowa Road, with larvae being most abundant from May to September, while nymphs were most abundant from August to November. Larvae and nymphs were most commonly collected in the woodland and gullies and least commonly in the grassland (p < 0.01). The lowest numbers of R. appendiculatus were collected in the mid-1990s after the 1991/1992 drought. Rhipicephalus zambeziensis numbers declined after 1991 and even further after 1998, dropping to their lowest levels during 2002. The changes in numbers of these two species reflected changes in rainfall and the populations of several of their large herbivore hosts, as well as differences in the relative humidity between the two sites over time.

scholarly journals Effect of burning on the numbers of questing ticks collected by dragging

2006 ◽  
Vol 73 (3) ◽  
Author(s):  
I.G. Horak ◽  
G.J. Gallivan ◽  
A.M. Spickett ◽  
A.L.F. Potgieter
Keyword(s):  
Tick Species ◽  
National Park ◽  
Host Preference ◽  
Term Effect ◽  
Kruger National Park ◽  
Ixodid Ticks ◽  
Short Term ◽  
Experimental Burn ◽  
Major Species ◽  
Questing Ticks

Sixteen experimental burn plot replicates, in groups of four, in four landscape zones of the Kruger National Park, South Africa, and from which wildlife are not excluded, have been subjected to fixed, regular burning regimens since 1954. In 1999, a study to determine the effect of burning on ixodid ticks questing for hosts from the vegetation of the plots was initiated, and six sub-plots, with identical histories, within each of two of the burn plot replicates in Combretum collinum / Combretum zeyheyri woodland on granite, were selected. With few exceptions these 12 sub-plots, as well as unburned vegetation adjacent to each of the replicates, were sampled for ticks at monthly intervals for a period of 39 months by dragging with flannel strips. The existing regimen of burning during August or during October on individual sub-plots was continued during this time. A total of 14 tick species was recovered from the plots of which nine could be considered major species. Sufficient numbers for statistical analysis of only eight species were, however, collected. Burning appeared to have little short-term effect on the number of ticks recovered. In the longer term, the response varied from no change, an increase, or a decrease in the numbers of ticks collected each year after burning. Tick species, life cycle, seasonality, questing strategy, host preference and host utilization of the habitat were important determinants of the effect of burning.

scholarly journals Global Distribution of Babesia Species in Questing Ticks: A Systematic Review and Meta-Analysis Based on Published Literature

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 230
Author(s):  
ThankGod E. Onyiche ◽  
Cristian Răileanu ◽  
Susanne Fischer ◽  
Cornelia Silaghi
Keyword(s):  
Tick Species ◽  
Meta Analysis ◽  
Mammalian Species ◽  
Molecular Techniques ◽  
Ixodid Ticks ◽  
Babesia Microti ◽  
Babesia Species ◽  
Nested Polymerase Chain Reaction ◽  
Questing Ticks ◽  
Veterinary Importance

Babesiosis caused by the Babesia species is a parasitic tick-borne disease. It threatens many mammalian species and is transmitted through infected ixodid ticks. To date, the global occurrence and distribution are poorly understood in questing ticks. Therefore, we performed a meta-analysis to estimate the distribution of the pathogen. A deep search for four electronic databases of the published literature investigating the prevalence of Babesia spp. in questing ticks was undertaken and obtained data analyzed. Our results indicate that in 104 eligible studies dating from 1985 to 2020, altogether 137,364 ticks were screened with 3069 positives with an estimated global pooled prevalence estimates (PPE) of 2.10%. In total, 19 different Babesia species of both human and veterinary importance were detected in 23 tick species, with Babesia microti and Ixodesricinus being the most widely reported Babesia and tick species, respectively. Regardless of species, adult ticks with 2.60% had the highest infection rates, while larvae had the least with 0.60%. Similarly, female ticks with 4.90% were infected compared to males with 3.80%. Nested-polymerase chain reaction (PCR) 2.80% had the highest prevalence among the molecular techniques employed. In conclusion, results obtained indicate that Babesia species are present in diverse questing tick species at a low prevalence, of which some are competent vectors.

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 contribution of fire research to fire management: a critical review of a long-term experiment in the Kruger National Park, South Africa

2007 ◽  
Vol 16 (5) ◽  
pp. 519 ◽  
Author(s):  
Brian W. van Wilgen ◽  
Navashni Govender ◽  
Harry C. Biggs
Keyword(s):  
South Africa ◽  
National Park ◽  
Fire Management ◽  
Basic Research ◽  
Kruger National Park ◽  
Management Policy ◽  
Wet Season ◽  
Long Term Experiment ◽  
Faunal Communities

The present paper reviews a long-term fire experiment in the Kruger National Park, South Africa, established in 1954 to support fire management. The paper’s goals are: (1) to assess learning, with a focus on relevance for fire management; (2) to examine how findings influenced changes in fire management; and (3) to reflect on the experiment’s future. Results show that fire treatments affected vegetation structure and biomass more than species composition. Effects on vegetation were most marked in extreme treatments (annual burning, burning in the summer wet season, or long periods of fire exclusion), and were greater in areas of higher rainfall. Faunal communities and soil physiology were largely unaffected by fire. Since the inception of the experiment, paradigms in savanna ecology have changed to encompass heterogeneity and variability. The design of the experiment, reflecting the understanding of the 1950s, does not cater for variability, and as a result, the experiment had little direct influence on changes in management policy. Notwithstanding this, managers accept that basic research influences the understanding of fundamental ecosystem function, and they recognise that it promotes appropriate adaptive management by contributing to predictive understanding. This has been a major reason for maintaining the experiment for over 50 years.

scholarly journals Seven decades of institutional learning: managing alien plant invasions in the Kruger National Park, South Africa

Oryx ◽  
2007 ◽  
Vol 41 (2) ◽  
pp. 160-167 ◽  
Author(s):  
Llewellyn C. Foxcroft ◽  
Stefanie Freitag-Ronaldson
Keyword(s):  
South Africa ◽  
National Park ◽  
Invasive Plant ◽  
Current Control ◽  
Kruger National Park ◽  
Plant Management ◽  
Plant Interactions ◽  
Alien Plant ◽  
Invasive Plant Management

AbstractLong-term ecological and economic sustainability will ultimately determine the outcome of any conservation management programme. Invasive alien plants, first recorded in the Kruger National Park, South Africa, in 1937, are now recognized as one of the greatest threats to the biodiversity of this Park. Such plants have been managed in the Park since 1956, with control advancing mainly through a process of trial and error. Refinement of invasive plant management strategies has resulted in an understanding of the target plants' biology and ecology, herbicide use and herbicide-plant interactions, as well as the plant-insect interactions of biological control. Careful integration of different control methods has proved essential to ensure the most appropriate use of techniques to deliver the best possible results from the resources available and achieve long-term sustainability. We outline the development of control efforts and current control programmes and the process of their incorporation into the institutional memory of Kruger National Park over the last 7 decades.

scholarly journals Relationships between reproduction and environment in the Hippopotamus Hippopotamus Amphibius in the Kruger National Park

Koedoe ◽  
1981 ◽  
Vol 24 (1) ◽  
Author(s):  
G. L Smuts ◽  
I. J Whyte
Keyword(s):  
Environmental Conditions ◽  
National Park ◽  
Indirect Evidence ◽  
Reproductive Rate ◽  
Kruger National Park ◽  
High Survival ◽  
Calf Survival ◽  
Hippopotamus Amphibius ◽  
Adverse Environmental Conditions

Hippopotamus Hippopotamus amphibius reproduction in the Kruger National Park, Republic of South Africa, is described and compared with that of other populations in Africa and with captive reared specimens. Information collected during drought and pluvial periods indicates that adult hippo cows react to adverse environmental conditions (reduced shelter in pools, overcrowding and food scarcity) by marked declines in conception rates (from 36,7 @ 5,6). Indirect evidence indicates that when environmental conditions are unfavourable calf survival is improved by extending the period of lactation and by calves suckling more than one cow. During favourable years some calves mature early (S S, 2 years, and 9 9 5 years) but generally sexual maturity is attained at six and 9-10 years for males and females respectively. The calving interval, when environmental conditions are favourable, is about two years and reproductive senescence and sterility are insignificant factors. The population sex ratio is 1:1. Hippos appear to be typical K-selected species. Environmental constraints have caused them to adopt a low reproductive rate and high survival rate and consequently a close adjustment to the long-term carrying capacity of the environment.

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