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 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 monitoring of plant morfological types in response to herbivory and fire in the Kruger National Park

2012 ◽  
Vol 31 (1) ◽  
Author(s):  
D.C. Smith ◽  
F. Siebert ◽  
Pieter S. Kloppers
Keyword(s):  
Significant Variation ◽  
National Park ◽  
Kruger National Park ◽  
Plant Characteristics ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Over Time

Reseach was done on the Sodics of the Nkuhlu long-term monitoring exclosures.Variation in different plant characteristics were analised across different treatments over time. No significant variation in morphological types could be detected.

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 Long-Term historical and Projected Herbivore Population Dynamics in Ngorongoro Crater, Tanzania

2019 ◽  
Author(s):  
Joseph O. Ogutu ◽  
Patricia D Moehlman ◽  
Hans-Peter Piepho ◽  
Victor A Runyoro ◽  
Michael B Coughenour ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Population Size ◽  
Dry Season ◽  
Climate Change Scenarios ◽  
Wet Season ◽  
Large Herbivore ◽  
Herbivore Species ◽  
Dry Seasons ◽  
Wet And Dry Seasons

The Ngorongoro Crater is an intact caldera with an area of approximately 310 km2. Long term records on herbivore populations, vegetation and rainfall made it possible to analyze historic and project future herbivore population dynamics. In 1974 there was a perturbation in that resident Maasai and their livestock were removed from the Crater. Vegetation structure changed in 1967 from predominately short grassland to mid and tall grasses dominating in 1995. Even with a change in grassland structure, total herbivore biomass remained relatively stable from 1963 to 2012, implying that the crater has a stable multi-herbivore community. However, in 1974, Maasai pastoralists were removed from the Ngorongoro Crater and there were significant changes in population trends for some herbivore species. Buffalo, elephant and ostrich numbers increased significantly during 1974-2012. The zebra population was stable from 1963 to 2012 whereas numbers of other eight species declined substantially between 1974 and 2012 relative to their peak numbers during 1974-1976. Numbers of Grant’s and Thomson’s gazelles, eland, kongoni, waterbuck (wet season only) declined significantly in the Crater in both seasons after 1974. Wildebeest numbers decreased in the Crater between 1974 and 2012 but this decrease was not statistically significant. In addition, some herbivore species were consistently more abundant inside the Crater during the wet than the dry season. This pattern was most evident for the large herbivore species requiring bulk forage, comprising buffalo, eland, and elephant. Analyses of rainfall indicated that there was a persistent annual cycle of 4.83 years. Herbivore population size was correlated with rainfall in both the wet and dry seasons. The relationships established between the time series of historic animal counts in the wet and dry seasons and lagged wet and dry season rainfall series were used to forecast the likely future trajectories of the wet and dry season population size for each species under three alternative climate change scenarios.

scholarly journals Coral Reef Resilience in Taiwan: Lessons from Long-Term Ecological Research on the Coral Reefs of Kenting National Park (Taiwan)

2019 ◽  
Vol 7 (11) ◽  
pp. 388 ◽  
Author(s):  
Shashank Keshavmurthy ◽  
Chao-Yang Kuo ◽  
Ya-Yi Huang ◽  
Rodrigo Carballo-Bolaños ◽  
Pei-Jei Meng ◽  
...  
Keyword(s):  
Coral Reefs ◽  
National Park ◽  
Seawater Temperature ◽  
Ecological Research ◽  
Thermal Environments ◽  
Coral Reef Resilience ◽  
Long Term Ecological Research ◽  
Kenting National Park ◽  
Over Time

Coral reefs in the Anthropocene are being subjected to unprecedented levels of stressors, including local disturbances—such as overfishing, habitat destruction, and pollution—and large-scale destruction related to the global impacts of climate change—such as typhoons and coral bleaching. Thus, the future of corals and coral reefs in any given community and coral-Symbiodiniaceae associations over time will depend on their level of resilience, from individual corals to entire ecosystems. Herein we review the environmental settings and long-term ecological research on coral reefs, based on both coral resilience and space, in Kenting National Park (KNP), Hengchun Peninsula, southern Taiwan, wherein fringing reefs have developed along the coast of both capes and a semi-closed bay, known as Nanwan, within the peninsula. These reefs are influenced by a branch of Kuroshio Current, the monsoon-induced South China Sea Surface Current, and a tide-induced upwelling that not only shapes coral communities, but also reduces the seawater temperature and creates fluctuating thermal environments which over time have favoured thermal-resistant corals, particularly those corals close to the thermal effluent of a nuclear power plant in the west Nanwan. Although living coral cover (LCC) has fluctuated through time in concordance with major typhoons and coral bleaching between 1986 and 2019, spatial heterogeneity in LCC recovery has been detected, suggesting that coral reef resilience is variable among subregions in KNP. In addition, corals exposed to progressively warmer and fluctuating thermal environments show not only a dominance of associated, thermally-tolerant Durusdinium spp. but also the ability to shuffle their symbiont communities in response to seasonal variations in seawater temperature without bleaching. We demonstrate that coral reefs in a small geographical range with unique environmental settings and ecological characteristics, such as the KNP reef, may be resilient to bleaching and deserve novel conservation efforts. Thus, this review calls for conservation efforts that use resilience-based management programs to reduce local stresses and meet the challenge of climate change.

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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