Long-Term Population Dynamics of African Ungulates in Waterberg Plateau National Park, Namibia

2020 ◽  
Vol 67 (4) ◽  
pp. 339
Author(s):  
Evert Kasiringua ◽  
Şerban Procheş ◽  
Grzegorz Kopij
Author(s):  
Arthur M. Spickett ◽  
Gordon J. Gallivan ◽  
Ivan G. Horak

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.


Author(s):  
Aelita Pinter

Multiannual fluctuations ("cycles") in population density of small rodents doubtless result from the interaction of a multitude of factors, as evidenced by the variety of hypotheses proposed to explain the phenomenon (for reviews see Finerty 1980, Taitt and Krebs 1985). However, the inability of these hypotheses - alone or in combination - to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon. The objectives of this project are to continue a long-term study of the population dynamics of the montane vole, Microtus montanus, in Grand Teton National Park. On the basis of earlier observations (Pinter 1986, 1988) particular emphasis will be placed on how environmental variables, possibly acting through reproductive responses, contribute to the population density cycles of these rodents.


Author(s):  
Aelita Pinter

A variety of hypotheses have been proposed to explain multiannual fluctuations in population density ("cycles") of small rodents (for reviews see Finerty 1980, Taitt and Krebs 1985). Doubtless, such cycles - known since antiquity (Elton 1942) - result from an interaction of a multitude of factors. However, the inability of extant hypotheses, alone or in combination, to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon. The objectives of this project are to continue the long-term study of population dynamics of the montane vole, Microtus montanus, in Grand Teton National Park. Earlier observations (Pinter 1986, 1988) indicate that environmental variables might contribute to the population density cycles of these rodents, possibly by influencing their growth and various aspects of their reproduction.


Author(s):  
Ivan G. Horak ◽  
Gordon J. Gallivan ◽  
Arthur M. Spickett

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.


Author(s):  
Aelita Pinter

Multiannual fluctuations ("cycles") in population density of small rodents doubtless result from the interaction of a multitude of factors, as evidenced by the variety of hypotheses proposed to explain the phenomenon (for reviews see Finerty 1980, Taitt and Krebs 1985). However, the inability of these hypotheses - alone or in combination - to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon. The objectives of this project are to continue the long-term study of the population dynamics of the montane vole, Microtus montanus, in Grand Teton National Park. On the basis of earlier observations (Pinter 1986, 1988) particular emphasis will be placed on how environmental variables, possibly acting through reproductive responses, contribute to the population density cycles of these rodents.


Author(s):  
Aelita Pinter

A variety of hypotheses has been proposed to explain multiannual fluctuations in population density ("cycles") of small rodents (for reviews see Finerty 1980, Taitt and Krebs 1985). Doubtless, such cycles - known since antiquity (Elton 1942) - result from an interaction of a multitude of factors. However, the inability of extant hypotheses, alone or in combination, to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon. The objectives of this project are to continue the long-term study of population dynamics of the montane vole, Microtus montanus, in Grand Teton National Park. Earlier observations (Pinter 1986, 1988) indicate that environmental variables might contribute to the population density cycles of these rodents, possibly by influencing their growth and various aspects of their reproduction.


2017 ◽  
Vol 7 (4) ◽  
pp. 65-72
Author(s):  
V. N. Shmagol' ◽  
V. L. Yarysh ◽  
S. P. Ivanov ◽  
V. I. Maltsev

<p>The long-term population dynamics of the red deer (<em>Cervus elaphus</em> L.) and European roe deer (<em>Capreolus</em> <em>capreolus</em> L.) at the mountain and forest zone of Crimea during 1980-2017 is presented. Fluctuations in numbers of both species are cyclical and partly synchronous. Period of oscillations in the population of red deer is about 25 years, the average duration of the oscillation period of number of roe deer is 12.3 years. During the fluctuations in the number the increasing and fall in population number of the red deer had been as 26-47 %, and roe deer – as 22-34 %. Basing on the dada obtained we have assumed that together with large-scale cycles of fluctuations in population number of both red deer and roe deer the short cycles of fluctuations in the number of these species with period from 3.5 to 7.5 years take place. Significant differences of the parameters of cyclical fluctuations in the number of roe deer at some sites of the Mountainous Crimea: breaches of synchronicity, as well as significant differences in the duration of cycles are revealed. The greatest deviations from the average values of parameters of long-term dynamics of the number of roe deer in Crimea are noted for groups of this species at two protected areas. At the Crimean Nature Reserve the cycle time of fluctuations of the numbers of roe deer was 18 years. At the Karadag Nature Reserve since 1976 we can see an exponential growth in number of roe deer that is continued up to the present time. By 2016 the number of roe deer reached 750 individuals at a density of 437 animals per 1 thousand ha. Peculiarity of dynamics of number of roe deer at some sites proves the existence in the mountain forest of Crimea several relatively isolated groups of deer. We assumed that "island" location of the Crimean populations of red deer and European roe deer, their relatively little number and influence of permanent extreme factors of both natural and anthropogenic origination have contributed to a mechanism of survival of these populations. The elements of such a mechanism include the following features of long-term dynamics of the population: the reduction in the period of cyclic population fluctuations, while maintaining their amplitude and the appearance of additional small cycles, providing more flexible response of the population to the impact of both negative and positive environmental factors. From the totality of the weather conditions for the Crimean population of roe deer the recurring periods of increases and downs in the annual precipitation amount may have relevance. There was a trend of increase in the roe deer population during periods of increasing annual precipitation.</p>


2007 ◽  
Vol 158 (11) ◽  
pp. 349-352
Author(s):  
Grégory Amos ◽  
Ambroise Marchand ◽  
Anja Schneiter ◽  
Annina Sorg

The last Capricorns (Capra ibex ibex) in the Alps survived during the nineteenth century in the Aosta valley thanks to the royal hunting reservation (today Gran Paradiso national park). Capricorns from this reservation were successfully re-introduced in Switzerland after its Capricorn population had disappeared. Currently in Switzerland there are 13200 Capricorns. Every year 1000 are hunted in order to prevent a large variation and overaging of their population and the damage of pasture. In contrast, in the Gran Paradiso national park the game population regulates itself naturally for over eighty years. There are large fluctuations in the Capricorn population (2600–5000) which are most likely due to the climate, amount of snow, population density and to the interactions of these factors. The long-term surveys in the Gran Paradiso national park and the investigations of the capacity of this area are a valuable example for the optimal management of the ibexes in Switzerland.


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