Optimal harvesting of an age-structured, two-sex herbivore–plant system

Tahvonen, Olli; Kumpula, Jouko; Pekkarinen, Antti‐Juhani

doi:10.1016/j.ecolmodel.2013.09.029

Cited by 25 publications

(67 citation statements)

References 48 publications

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“…Eq. (5) thus differs from Tahvonen et al (2014) by giving a slightly smaller weight decrease when the daily energy intake is close to the requirement. Fig.…”

Section: Population Modelmentioning

confidence: 86%

“…In our study we further develop the reindeer-lichen optimization model presented in Tahvonen et al (2014). We expand the model with multiple winter energy resources, supplementary feeding, over-year lichen consumption, and two different lichen growth rates.…”

Section: The Model and Methodsmentioning

confidence: 99%

“…The growth function for mature and old pine forests (g = 1) is based on Kumpula et al (2000) and on new data collected in a long-term monitoring study at Kaamanen field station (Kumpula et al, unpublished, see more details from Tahvonen et al, 2014). However, results in Kumpula et al (2014) indicate that lichen production in young pine forests, logging areas, and mountain birch forests is approximately 60% and approximately 40% in mountain heaths of the production in old or mature pine forest.…”

Section: Lichen Modelmentioning

confidence: 96%

“…The control variable in these models is harvesting, which is chosen for maximizing the harvesting income over a long time period, and their results include optimal steadystate levels for lichen and reindeer densities. Both Moxnes et al (2001) and Tahvonen et al (2014) also include other cratered food resources besides ground lichens as winter fodder, but none of the previous studies consider the effects of arboreal lichens or supplementary feeding. All previous studies also assume that pasture rotation is used and winter pastures are consumed only during winter.…”

Section: Introductionmentioning

confidence: 96%

“…For this we use the dynamic ageand sex-structured reindeer-lichen optimization model presented by Tahvonen et al (2014). We expand the model by including arboreal lichens and supplementary food as winter energy resources for reindeer and by taking into account the reduction of lichen outside wintertime due to grazing and trampling by reindeer.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Reindeer management and winter pastures in the presence of supplementary feeding and government subsidies

Pekkarinen

Kumpula

Tahvonen

2015

Ecological Modelling

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“…Eq. (5) thus differs from Tahvonen et al (2014) by giving a slightly smaller weight decrease when the daily energy intake is close to the requirement. Fig.…”

Section: Population Modelmentioning

confidence: 86%

Section: The Model and Methodsmentioning

confidence: 99%

Section: Lichen Modelmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Reindeer management and winter pastures in the presence of supplementary feeding and government subsidies

Pekkarinen

Kumpula

Tahvonen

2015

Ecological Modelling

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Winter condition variability decreases the economic sustainability of reindeer husbandry

Pekkarinen

Rasmus

Kumpula

et al. 2022

Ecological Applications

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Wild and semidomesticated reindeer are one of the key species in Arctic and subarctic areas, and their population dynamics are closely tied to winter conditions. Difficult snow conditions have been found to decrease the calving success and survivability of reindeer, but the economic effects of variation in winter conditions on reindeer husbandry have not been studied. In this study, we combine state‐of‐the‐art economic–ecological modeling with the analysis of annual reindeer management reports from Finland. These contain local knowledge of herding communities. We quantify the occurrence probabilities of different types of winters from annual management reports and analyze the effects of this variation in winter conditions on reindeer husbandry using an age‐ and sex‐structured bioeconomic reindeer–lichen model. Our results show that difficult winters decrease the net revenues of reindeer husbandry. However, they also protect lichen pastures from grazing, thereby increasing future net revenues. Nonetheless, our solutions show that the variability of winter conditions overall decrease the net income of herders compared to constant winter conditions. Low lichen biomass appears to make reindeer management more sensitive to the effects of difficult winter conditions. We also found that it is economically sensible to use supplementary feeding during difficult winters, but the net revenues still decrease compared to average winters because of the high feeding costs. Overall, our analysis suggests that the increasing variability of winter conditions due to climate change will decrease net revenues in reindeer husbandry. This decrease will still occur even if the most extreme effects of climate change do not occur. This study shows that combining a state‐of‐the‐art bioeconomic model and practitioner knowledge can bring compatible insights, ideas, results, and a bottom‐up perspective to the discussion.

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Herbivore grazing—or trampling? Trampling effects by a large ungulate in cold high‐latitude ecosystems

Heggenes

Odland

Chevalier³

et al. 2017

Ecology and Evolution

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Mammalian herbivores have important top‐down effects on ecological processes and landscapes by generating vegetation changes through grazing and trampling. For free‐ranging herbivores on large landscapes, trampling is an important ecological factor. However, whereas grazing is widely studied, low‐intensity trampling is rarely studied and quantified. The cold‐adapted northern tundra reindeer (Rangifer tarandus) is a wide‐ranging keystone herbivore in large open alpine and Arctic ecosystems. Reindeer may largely subsist on different species of slow‐growing ground lichens, particularly in winter. Lichen grows in dry, snow‐poor habitats with frost. Their varying elasticity makes them suitable for studying trampling. In replicated factorial experiments, high‐resolution 3D laser scanning was used to quantify lichen volume loss from trampling by a reindeer hoof. Losses were substantial, that is, about 0.3 dm3 per imprint in dry thick lichen, but depended on type of lichen mat and humidity. Immediate trampling volume loss was about twice as high in dry, compared to humid thin (2–3 cm), lichen mats and about three times as high in dry vs. humid thick (6–8 cm) lichen mats, There was no significant difference in volume loss between 100% and 50% wetted lichen. Regained volume with time was insignificant for dry lichen, whereas 50% humid lichen regained substantial volumes, and 100% humid lichen regained almost all lost volume, and mostly within 10–20 min. Reindeer trampling may have from near none to devastating effects on exposed lichen forage. During a normal week of foraging, daily moving 5 km across dry 6‐ to 8‐cm‐thick continuous lichen mats, one adult reindeer may trample a lichen volume corresponding to about a year's supply of lichen. However, the lichen humidity appears to be an important factor for trampling loss, in addition to the extent of reindeer movement.

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Optimal harvesting of an age-structured, two-sex herbivore–plant system

Cited by 25 publications

References 48 publications

Reindeer management and winter pastures in the presence of supplementary feeding and government subsidies

Reindeer management and winter pastures in the presence of supplementary feeding and government subsidies

Winter condition variability decreases the economic sustainability of reindeer husbandry

Herbivore grazing—or trampling? Trampling effects by a large ungulate in cold high‐latitude ecosystems

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