Can management regulate the population size of wild reindeer (Rangifer tarandus) through harvest?

2012 ◽  
Vol 90 (2) ◽  
pp. 163-171 ◽  
Author(s):  
O. Strand ◽  
E.B. Nilsen ◽  
E.J. Solberg ◽  
J.C.D. Linnell
Keyword(s):  
Population Size ◽  
Rangifer Tarandus ◽  
Small Population ◽  
Population Estimates ◽  
Relative Role ◽  
Harvest Data ◽  
Closed Populations ◽  
Southern Norway ◽  
Wild Reindeer

We analyzed a 51-year time series of harvest data from a small population of wild mountain reindeer ( Rangifer tarandus (L., 1758)) in southern Norway and examined the relative role of biological and management related processes as drivers of its population dynamics. The population is monitored annually to obtain information on population size and structure, and since 1980, managers have attempted to stabilize the population at about 1.1 reindeer/km2. The harvest increased at a higher rate than the population size and was thus probably sufficient to not only limit but also regulate population size. Phase plot analyses showed that the population has varied around a density attractor of about 1.0 reindeer/km2 since 1980 and is therefore close to the targeted population size of 1.1 reindeer/km2. However, the annual harvest explained only 49% of the variation in population growth rate (λ) in a linear regression model, despite relatively low variation in population productivity (proportion of calves). Between 1999 and 2006, the population in Forolhogna declined by almost 50% before recovering to its previous size. We suggest that both imprecise population estimates and high harvest effectiveness at reduced population densities contributed to this decline. As such, this study points to some of the obstacles managers are facing when trying to stabilize productive ungulate populations even when they live in closed populations and in stable, predator-free environments.

scholarly journals Population Density or Populations Size. Which Factor Determines Urban Traffic Congestion?

2021 ◽  
Vol 13 (8) ◽  
pp. 4280
Author(s):  
Yu Sang Chang ◽  
Sung Jun Jo ◽  
Yoo-Taek Lee ◽  
Yoonji Lee
Keyword(s):  
Population Density ◽  
Population Size ◽  
Traffic Congestion ◽  
Critical Role ◽  
Small Population ◽  
High Density ◽  
Urban Traffic ◽  
Contradictory Result ◽  
Low Density

A large number of articles have documented that as population density of cities increases, car use declines and public transit use rises. These articles had a significant impact of promoting high-density compact urban development to mitigate traffic congestion. Another approach followed by other researchers used the urban scaling model to indicate that traffic congestion increases as population size of cities increases, thus generating a possible contradictory result. Therefore, this study examines the role of both density and population size on traffic congestion in 164 global cities by the use of Stochastic Impacts by Regression on Population, Affluence and Technology model. We divide 164 cities into the two subgroups of 66 low density cities and 98 high density cities for analysis. The findings from the subgroups analysis indicated a clear-cut difference on the critical role of density in low-density cities and the exclusive role of population size in high-density cities. Furthermore, using threshold regression model, 164 cities are divided into the two regions of large and small population cities to determine population scale advantage of traffic congestion. Our findings highlight the importance of including analysis of subgroups based on density and/or population size in future studies of traffic congestion.

scholarly journals The Sundrun population of wild reindeer

Rangifer ◽  
2003 ◽  
Vol 23 (5) ◽  
pp. 193
Author(s):  
Ivan Sivtsev
Keyword(s):  
Population Dynamics ◽  
Sex Ratio ◽  
Rangifer Tarandus ◽  
Population Estimates ◽  
Seasonal Migrations ◽  
Wintering Areas ◽  
The 1950S ◽  
Wild Reindeer ◽  
Separate Population

The Sundrun wild reindeer (Rangifer tarandus) herd was recognized as a separate population during the 1950s. Since then, the herd has ranged over an area of approximately 180 000 km2 between the Indigirka and Kolyma Rivers in northeastern Yakutia. Population dynamics and movements were investigated between 1987 and 1997. During this period, the population estimates ranged from 25 000 to 45 000 reindeer, the sex ratio averaged 55 bulls:100 cows, and the percentage of calves in the herd ranged between 17% and 25%. The main routes of seasonal migrations, wintering areas, and the location of calving areas are discussed.

Vigilance and fright behaviour in the insular Svalbard reindeer (Rangifer tarandus platyrhynchus)

2011 ◽  
Vol 89 (8) ◽  
pp. 753-764 ◽  
Author(s):  
Eigil Reimers ◽  
Steinar Lund ◽  
Torbjørn Ergon
Keyword(s):  
Human Activities ◽  
Rangifer Tarandus ◽  
Lower Probability ◽  
Supporting Evidence ◽  
Svalbard Archipelago ◽  
Svalbard Reindeer ◽  
Vigilance Behaviour ◽  
Southern Norway ◽  
Wild Reindeer ◽  
Flight Initiation

The insular Svalbard reindeer ( Rangifer tarandus platyrhynchus Vrolik, 1829) provide an opportunity to study vigilance behaviour in the absence of predators and parasitizing insects. We measured vigilance and fright and flight response during summer 2006 in the Svalbard archipelago; in four areas on Nordenskiöld Land on the island Spitzbergen and in one area on the island Edgeøya. Vigilance was higher in reindeer on Edgeøya than in the four Spitzbergen areas. Males were less vigilant than lactating and barren females and vigilance decreased with increasing group size. The relaxed vigilance behaviour in Svalbard reindeer compared with wild reindeer in southern Norway demonstrates a vigilance threshold in the absence of traditional predators of Rangifer Hamilton Smith, 1827. Alert, flight initiation, and escape distances were all shorter in Adventdalen, with Longyearbyen and its considerably higher amounts of human activities and infrastructure than in the other study areas, supporting evidence of habituation towards humans. There were no systematic vigilance or differences in fright and flight responses between reindeer in Colesdalen, Reindalen, and Sassendalen, indicating that a combination of low level of human activities including hunting, recreation, and scientific activities affected the animals differently. Lower probability of assessing before fleeing in Edgeøya (63% vs. 94% in the Nordenskiöld Land areas), along with their higher vigilance, may indicate more frequent interactions with polar bears ( Ursus maritimus Phipps, 1774) in Edgeøya.

Relative role of population density and climatic factors in shaping the body growth rate of Lilford’s Wall Lizard (Podarcis lilfordi)

2016 ◽  
Vol 94 (3) ◽  
pp. 207-215 ◽  
Author(s):  
A. Rotger ◽  
J.M. Igual ◽  
J.J. Smith ◽  
G. Tavecchia
Keyword(s):  
Growth Rate ◽  
Population Size ◽  
Climatic Factors ◽  
Body Growth ◽  
The Body ◽  
Relative Role ◽  
Podarcis Lilfordi ◽  
Capita Food ◽  
Per Capita

The body growth rate in small reptiles is modulated by per-capita food resources and recent evidences suggested that this constraint is the mechanism underlying differences between cohorts. Per-capita food resources depend on population size and climatic factors, but their relative role in explaining the variations in growth rate is unclear. We used morphological data collected over 6 years to model the body growth of an insular lizard (Lilford’s Wall Lizard, Podarcis lilfordi (Günther, 1874)). We used nonlinear equations to describe the appropriate length-at-age relationship. For each sex, seasonal growth was observed and the oscillatory von Bertalanffy curve was fitted to the data. Three age classes were recognized, and we investigated the relative role of density, spring rainfall, and temperature in explaining the variation of the growth rate in each sex-by-age class. Results showed that the relative role of density and climatic factors varied according to the age considered. While population size and temperature had a negative effect on the growth rate of juveniles, rainfall had a positive influence on the growth of subadults. Adult growth was near zero and constant over time. The different role of density-dependent and climatic factors in explaining age-dependent growth rate provides an important insight in understanding lizard population dynamics and life-history tactics.

scholarly journals Linking Social Values of Wild Reindeer to Planning and Management Options in Southern Norway

ARCTIC ◽  
2017 ◽  
Vol 70 (2) ◽  
pp. 129 ◽  
Author(s):  
Bjørn P. Kaltenborn ◽  
Mehmet Mehmetoglu ◽  
Vegard Gundersen
Keyword(s):  
Rangifer Tarandus ◽  
Population Based ◽  
Knowledge Bases ◽  
Value Orientations ◽  
Path Modeling ◽  
Management Options ◽  
Ecological Requirements ◽  
Management Regime ◽  
Southern Norway ◽  
Wild Reindeer

Norway is home to the last remaining populations of wild mountain reindeer (Rangifer tarandus tarandus) in Europe. Concerns over anthropogenic and natural drivers have led to change in the management regime from a population-based model to an area-based model. More complex management goals, increasing involvement of stakeholders, and larger management units call for improved knowledge about reindeer-related values. We examined the responses of 1000 respondents to 39 statements of attitudes and values associated with wild reindeer presence and the management situation in two reindeer regions of southern Norway. We used a partial least-squares path modeling approach to examine the nexus between the attraction of wild reindeer, sustainability concerns, utilitarian and non-utilitarian values, conflicts, and attitudes toward hunting. The results show that local concepts of the sustainability of reindeer are based on opinions about the ecological requirements as well as the roles reindeer can play in the social and economic development of the communities. The attraction of reindeer is a function of consumptive as well as non-consumptive objectives. Segments of the community with different consumptive orientations can share ideas about the attraction of reindeer, but diverge in their interpretation of the sustainability of the species. Improved knowledge about the diversity and complexity of value orientations associated with wild reindeer can be a useful tool for developing multi-objective management frameworks with a diversity of stakeholders who may share similar values and interests, although they have different experience and knowledge bases.

scholarly journals The effect of the light environment on population size of the epiphytic herb, Lepanthes rupestris (Orchidaceae)

Lankesteriana ◽  
2015 ◽  
Vol 7 (1-2) ◽  
Author(s):  
Francheska Ruiz-Canino ◽  
Denny Fernández ◽  
Elvia Meléndez-Ackerman ◽  
Raymond Tremblay
Keyword(s):  
Population Size ◽  
Light Environment ◽  
Relative Role ◽  
Plant Populations ◽  
Plant Survival ◽  
Density Dependent ◽  
Demographic Dynamics ◽  
Survival And Reproduction

The demographic dynamics of plant populations will depend on the relative role of density-dependent versus density-independent factors on population reg- ulation. Density-independent factors (i.e. changes in climate, fire, hurricanes) will affect plant survival and reproduction within a population in a manner that is independent of the density of individuals. 

scholarly journals Host in reserve: the role of common shrews (Sorex araneus) as a stable supplementary source of tick hosts in small mammal communities influenced by rodent population cycles

2021 ◽  
Author(s):  
Nicolas De Pelsmaeker ◽  
Lars Korslund ◽  
Øyvind Steifetten
Keyword(s):  
Population Size ◽  
Population Cycles ◽  
Sorex Araneus ◽  
Host Population ◽  
Climatic Conditions ◽  
Myodes Glareolus ◽  
Northern Latitudes ◽  
Annual Population ◽  
Southern Norway

In recent decades, warming temperatures and changes in land use are supposed to have enabled several tick species to expand their distribution limit northwards. The progression of ticks to new areas may introduce new and emerging tick-borne pathogens as well as increase existing diseases. Aside from climatic conditions, ticks are dependent on hosts for survival, and rodents often act as important hosts for ticks and as pathogen reservoirs. At northern latitudes, rodents often undergo multi-annual population cycles, and the periodic absence of hosts may inhibit the further progression of ticks. We investigated the potential role of common shrews (Sorex araneus) to serve as a stable host source to immature life stages of a generalist tick Ixodes ricinus and a specialist tick I. trianguliceps, during decreasing abundances of bank voles (Myodes glareolus). We tested whether ticks would have a propensity to parasitize a certain host type dependent on host population size and composition in two high latitude locations in southern Norway, by comparing tick burdens on trapped animals. We found that I. ricinus larvae showed an equal propensity to parasitize both host types as the host population composition changed, but voles had a higher level of parasitism by nymphs (p< 0.004). An overall larger host population size favored the parasitism of voles by larvae (p= 0.027), but not by nymphs (p= 0.074). I. trianguliceps larvae showed a higher propensity to parasitize shrews, regardless of host population size or composition (p= 0.004), while nymphs parasitized shrews more as vole abundance increased (p= 0.002). The results indicate that common shrews may have the potential to act as a replacement host during periods of low rodent availability, but long-term observations encompassing complete rodent cycles may determine whether shrews are able to maintain tick range expansion despite low rodent availability.

scholarly journals The Hardangervidda wild reindeer herd: a problematic management history

Rangifer ◽  
2014 ◽  
Vol 34 (1) ◽  
pp. 57 ◽  
Author(s):  
Dag K. Bjerketvedt ◽  
Eigil Reimers ◽  
Howard Parker ◽  
Reidar Borgstrøm
Keyword(s):  
Rangifer Tarandus ◽  
Survey Methodology ◽  
Population Data ◽  
Herd Size ◽  
Small Areas ◽  
Independent Evaluation ◽  
Mammalian Predators ◽  
Southern Norway ◽  
Harvest Quotas ◽  
Wild Reindeer

The unique and internationally important wild reindeer Rangifer tarandus herd on the Hardangervidda plateau of southern Norway  has shown frequent and extreme fluctuations in harvest numbers for the past 60 years, despite considerable effort to stabilize the herd size at a winter carrying capacity of  9000 – 12 000 animals . In the absence of large mammalian predators, herd size is managed through hunting.  Here we attempt to unravel the causes of the management problems related to this population by examining the relative roles of historical, biological and management-related processes. From 1900 - 1950 the population remained mainly low due to a combination of generous harvest quotas, poaching and competition from domestic reindeer.  From 1950 - 2012 three extreme harvest peaks of between 4500 - 9500 animals occurred, followed by three equally extreme troughs including two shorter periods of total protection.  This extreme harvest fluctuation contrasts with the estimated annual harvest of 2300 - 3000 needed to stabilize the winter herd between 9000 - 12 000 animals.  We conclude that this population has been difficult to manage mainly because of 1) a management based on frequently unreliable population data on herd size (especially before 2001), 2) lack of  in depth analyses and evaluation of both recruitment and sex and age composition and 3) a low and highly variable harvest success (harvest/quota) due mainly to poor hunter mobility, a disadvantage when reindeer must be harvested from large flocks that constantly move upwind, seeking refuge on small areas with few hunters.  More reliable population data to create better harvest models plus increased hunter mobility are necessary to attain a more sustainable herd size, implying an improvement of the current herd survey methodology available to local reindeer boards.  Finally, a critical and independent evaluation of the scientific methodology employed to study and manage this herd is needed.

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