113 research outputs found
Reindeer behavioural ecology and use of pastures in pastoral livelihoods
Reindeer pastoralists have, for centuries, followed free-roaming animals throughout the Eurasian Arctic. The closing of national borders about a century ago forced the reindeer pastoralists to adapt to new conditions. Today, environmental conditions are changing rapidly with climate and land use change. Local history, migration and pasture use strategies of reindeer herding, and also the biogeography of grazing grounds during summer and winter, differ considerably between the countries. These differences also affect interactions with other forms of land use. Coexistence between reindeer husbandry and other interests requires an understanding of the differing preconditions in the natural environment. The main scope of this chapter is reindeer forage selection and adaptation to the arctic environment, as well as the use of pastures by reindeer and for reindeer husbandry and what affects their use during different seasons
The role of predation and food limitation on claims for compensation, reindeer demography and population dynamics
1.A major challenge in biodiversity conservation is to facilitate viable populations of large apex predators in ecosystems where they were recently driven to ecological extinction due to resource conflict with humans. 2. Monetary compensation for losses of livestock due to predation is currently a key instrument to encourage humanâcarnivore coexistence. However, a lack of quantitative estimates of livestock losses due to predation leads to disagreement over the practise of compensation payments. This disagreement sustains the humanâcarnivore conflict. 3. The level of depredation on year-round, free-ranging, semi-domestic reindeer by large carnivores in Fennoscandia has been widely debated over several decades. In Norway, the reindeer herders claim that lynx and wolverine cause losses of tens of thousands of animals annually and cause negative population growth in herds. Conversely, previous research has suggested that monetary predator compensation can result in positive population growth in the husbandry, with cascading negative effects of high grazer densities on the biodiversity in tundra ecosystems. 4. We utilized a long-term, large-scale dataset to estimate the relative importance of lynx and wolverine predation and density-dependent and climatic food limitation on claims for losses, recruitment and population growth rates in Norwegian reindeer husbandry. 5. Claims of losses increased with increasing predator densities, but with no detectable effect on population growth rates. Density-dependent and climatic effects on claims of losses, recruitment and population growth rates, were much stronger than the effects of variation in lynx and wolverine densities. 6. Synthesis and applications. Our analysis provides a quantitative basis for predator compensation and estimation of the costs of reintroducing lynx and wolverine in areas with free-ranging semidomestic reindeer. We outline a potential path for conflict management which involves adaptive monitoring programs, open access to data, herder involvement, and development of management strategy evaluation (MSE) models to disentangle complex responses including multiple stakeholders and individual harvester decisions. depredation, humanâcarnivore conflict, MODIS, onset of spring, plant productivity, predator compensation, Rangife
Environmental variation as a driver of predator-prey interactions
Animals often face the trade-off of optimizing foraging while limiting predation. In variable
and seasonal environments the availability of resources changes spatially and temporally, forcing animals
to adapt their spatial foraging patterns over time and, thus, to modify their exposure to predation. Previous
research has mostly dealt with the causes and consequences of animal spatial patterns separately, with
studies either examining how changes in the environment influence habitat selection, or determining the
effects of habitat use on vulnerability to predation. Here we combine these aspects through an examination
of how weather conditions affect predation risk by modifying the spatial behavior of the prey. We used
reindeer calves (Rangifer tarandus) in Norway to investigate (1) the environmental causes and (2) the
survival consequences of habitat use. We further examined how those relationships varied temporally and
according to the body mass of calves. We found that deep snow and ice conditions led reindeer to shift
from their usually preferred high-elevation pastures to lowland forested areas. This increase in forest use
was associated with lower calf survival, mostly due to elevated lynx (Lynx lynx) predation rates. Golden
eagles (Aquila chrysaetos) and wolverines (Gulo gulo) also preyed on calves but their effect was much smaller
and not associated with a specific habitat type. The link between climatic conditions, habitat use, and
predation changed over the winter season and depended on the body weights of the calves. The effect of
harsh weather conditions on reindeer use of forested habitats was stronger towards the end of the winter,
which coincides with more deteriorated body conditions and lower food availability on high-elevation
pastures, and predation probabilities were higher for smaller individuals. Our study demonstrates that
environmental variation importantly affects predator-prey interactions.
Key words: ecological trade-off; habitat use; Norwegian semidomestic reindeer; predation rates; predator-prey
dynamics; Rangifer tarandus; seasonal environments; ungulate foraging ecology; weather variability.publishedVersio
Unfounded claims about productivity beyond density for reindeer pastoralism systems
We point out problems with the article Productivity beyond density: A critique of management models for reindeer
pastoralism in Norway by Marin and co-workers published in Pastoralism in 2020. In our opinion, there are several
misleading claims about the governance of the reindeer pastoralist system in Norway, the RĂžros model for herd
management and density dependence in reindeer herds in their article. We point out the errors in their empirical
re-evaluation of previous work on the relationship between reindeer densities and the productivity and slaughter
weights in herds. These errors have a significant bearing on their conclusions. We agree that weather variability has
a substantial impact on reindeer body mass growth, fecundity and survival, but disagree with Marin et al. when
they argue that reindeer densities are of minor importance for reindeer productivity and animal welfare
Rangifer management controls a climate-sensitive tundra state transition
Source at https://doi.org/10.1002/eap.1618 .Rangifer (caribou/reindeer) management has been suggested to mitigate the temperature-
driven transition of Arctic tundra into a shrubland state, yet how this happens is
uncertain. Here we study this much focused ecosystem state transition in riparian areas, where
palatable willows (Salix) are dominant tall shrubs and highly responsive to climate change. For
the state transition to take place, small life stages must become tall and abundant. Therefore
we predicted that the performance of small life stages (potential recruits) of the tall shrubs were
instrumental to the focal transition, where Rangifer managed at high population density would
keep the small-stage shrubs in a âbrowse trapâ independent of summer temperature. We used a
large-scale quasi-experimental study design that included real management units that spanned
a wide range of Rangifer population densities and summer temperatures in order to assess the
relative importance of these two driving variables. Ground surveys provided data on density
and height of the small shrub life stages, while the distributional limit (shrubline) of established
shrublands (the tall shrub life stage) was derived from aerial photographs. Where Rangifer densities
were above a threshold of approximately 5 animals/km2, we found, in accordance with
the expectation of a âbrowse trap,â that the small life stages of shrubs in grasslands were at low
height and low abundance. At Rangifer densities below this threshold, the small life stages of
shrubs were taller and more abundant indicating Rangifer were no longer in control of the
grassland state. For the established shrubland state, we found that the shrubline was at a 100-
m lower elevation in the management units where Rangifer had been browsing in summer as
opposed to the migratory ranges with no browsing in summer. In both seasonal ranges, the
shrubline increased 100 m per 1°C increment in temperature. Our study supports the proposal
that Rangifer management within a sustainable range of animal densities can mitigate the
much-focused transition from grassland to shrubland in a warming Arctic.
browse trap; browsing; climate change; life history stage; plantâherbivore interactions; Salix;
shrub growth; shrubline; summer temperature
ANALISIS PEMAHAMAN KONSEP MATEMATIKA SISWA DENGAN MODEL PEMBELAJARAN PROBLEM BASED LEARNING PADA POKOK BAHASAN SEGITIGA (Study deskriptif di Kelas VII SMP Negeri 2 Plered Kab. Cirebon)
Anggun Maya Sari. NIM 59451058. âAnalisis Pemahaman Konsep
Matematika Siswa dengan Model Pembelajaran Problem Based Learning
pada Pokok Bahasan Segitigaâ. (Studi Deskriptif di Kelas VII SMP Negeri 2
Plered).
Pembelajaran yang efektif adalah pembelajaran yang menyediakan
kesempatan kepada siswa untuk belajar mandiri, sehingga dalam prosesnya siswa
dapat memperoleh pemahaman dan pengetahuan dengan lebih mendalam. Akan
tetapi proses kegiatan pembelajaran matematika yang berlangsung disekolah, pada
umumnya guru hanya sekedar penyampai informasi tanpa mempertimbangkan
seberapa jauh pemahaman siswa terhadap konsep matematika dari pokok bahasan
segitiga yang disampaikan.
Tujuan penelitian ini adalah 1) mengetahui seberapa besar pemahaman
konsep yang dimiliki peserta didik; 2) mengetahui factor pendukung dan
penghambat peserta didik dalam memahami konsep yang diberikan; 3)
mengetahui deskripsi aktivitas siswa dalam memahami konsep matematika
melalui model pembelajaran Problem Based Learning; 4) mengetahui respon
siswa setelah melaksanakan model pembelajaran Problem Based Learning; 5)
mengetahui sejauhmana pemahaman konsep matematika siswa setelah mengikuti
proses pembelajaran Problem Based Learning.
Penerapan model pembelajaran Problem Based Learning (PBL)
merupakan salah satu model pembelajaran yang dapat memberikan kondisi belajar
aktif kepada siswa. Dengan diterapkannya pembelajaran matematika dengan
model pembelajaran PBL, diharapkan dapat membantu siswa dalam memahami
konsep matematika.
Penelitian ini menggunakan pendekatan kualitatif dan kuantitatif dengan
metode deskriptif. Pengumpulan data menggunakan lembar observasi, pedoman
wawancara, angket dan tes. Informan dalam penelitian ini adalah kelas VII yang
sudah dibentuk kelompok kelas, yaitu VII A, VII D dan VII F. dengan
menggunakan proportionate stratified random sampling, maka dari masingmasing
kelompok kelas didapat 18 siswa sebagai informan penelitian.
Berdasarkan dari hasil wawancara tentang siswa dalam pemahaman konsep
matematika, diperoleh siswa masih kurang dan masih perlu banyak bimbingan.
Aktivitas siswa selama pembelajaran melalui model pembelajaran PBL diperoleh
dari hasil lembar observasi dengan nilai rata-rata dari semua aspek sebesar 54,39%
yang termasuk dalam kategori sedang. Berdasarkan angket respon siswa setelah
dilaksanakan model pembelajaran PBL termasuk dalam kategori baik dengan nilai
rata-rata 76,44%. Pemahaman konsep matematika siswa setelah mengikuti proses
pembelajaran dengan model pembelajaran PBL diperoleh siswa lebih rajin dalam
mencari bahan untuk menyelesaikan soal-soal yang diberikan dan menambah
pemahaman siswa mengenai konsep matematika, meski masih belum 100% benar,
dan hasil tes didapat nilai rata-rata 39% yang termasuk dalam kategori sangat
kurang.
Kata Kunci: Pemahaman konsep matematika, Problem Based Learning, Segitig
Berettiget kritikk av NMBU sin reindriftsforskning
Source at https://forskersonen.no/akademia-debattinnlegg-dyrevelferd/berettiget-kritikk-av-nmbu-sin-reindriftsforskning/1956081Det er flere elementer i artikkelen til NMBU-forskerne som fremstÄr som uforenlig med god vitenskapelig praksis
Spring phenology shapes the spatial foraging behavior of Antarctic petrels
In polar seas, the seasonal melting of ice triggers the development of an open-water ecosystem characterized by short-lived algal blooms, the grazing and development of zooplankton, and the influx of avian and mammalian predators. Spatial heterogeneity in the timing of ice melt generates temporal variability in the development of these events across the habitat, offering a natural framework to assess how foraging marine predators respond to the spring phenology. We combined 4 yr of tracking data of Antarctic petrels Thalassoica antarctica with synoptic remote-sensing data on sea ice and chlorophyll a to test how the development of melting ice and primary production drive Antarctic petrel foraging. Cross-correlation analyses of first-passage time revealed that Antarctic petrels utilized foraging areas with a spatial scale of 300 km. These areas changed position or disappeared within 10 to 30 d and showed no spatial consistency among years. Generalized additive model (GAM) analyses suggested that the presence of foraging areas was related to the time since ice melt. Antarctic petrels concentrated their search effort in melting areas and in areas that had reached an age of 50 to 60 d from the date of ice melt. We found no significant relationship between search effort and chlorophyll a concentration. We suggest that these foraging patterns were related to the vertical distribution and profitability of the main prey, the Antarctic krill Euphausia superba. Our study demonstrates that the annual ice melt in the Southern Ocean shapes the development of a highly patchy and elusive food web, underscoring the importance of flexible foraging strategies among top predators
Estimating the cumulative impact and zone of influence of anthropogenic features on biodiversity
1. The concept of cumulative impacts is widespread in policy documents, regulations and ecological studies, but quantification methods are still evolving. Infrastructure development usually takes place in landscapes with preexisting anthropogenic features. Typically, their impact is determined by computing the distance to the nearest feature only, thus ignoring the potential cumulative impacts of multiple features. We propose the cumulative ZOI approach to assess whether and to what extent anthropogenic features lead to cumulative impacts.2. The approach estimates both effect size and zone of influence (ZOI) of anthropogenic features and allows for estimation of cumulative effects of multiple features distributed in the landscape. First, we use simulations and an empirical study to understand under which circumstances cumulative impacts arise. Second, we demonstrate the approach by estimating the cumulative impacts of tourist infrastructure in Norway on the habitat of wild reindeer (Rangifer t. tarandus), a near-threatened species highly sensitive to anthropogenic disturbance.3. In the simulations, we showed that analyses based on the nearest feature and our cumulative approach are indistinguishable in two extreme cases: when features are few and scattered and their ZOI is small, and when features are clustered and their ZOI is large. The empirical analyses revealed cumulative impacts of private cabins and tourist resorts on reindeer, extending up to 10 and 20 km, with different decaying functions. Although the impact of an isolated private cabin was negligible, the cumulative impact of `cabin villages' could be much larger than that of a single large tourist resort. Focusing on the nearest feature only underestimates the impact of `cabin villages' on reindeer.4. The suggested approach allows us to quantify the magnitude and spatial extent of cumulative impacts of point, linear, and polygon features in a computationally efficient and flexible way and is implemented in the oneimpact R package. The formal framework offers the possibility to avoid widespread underestimations of anthropogenic impacts in ecological and impact assessment studies and can be applied to a wide range of spatial response variables, including habitat selection, population abundance, species richness and diversity, community dynamics and other ecological processes
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