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Estimation of boreal forest biomass from ICESat-2 data using hierarchical hybrid inference
Get PDFThe ICESat-2, launched in 2018, carries the ATLAS instrument, which is a photon-counting spaceborne lidar that provides profile samples over the terrain. While primarily designed for snow and ice monitoring, there has been a great interest in using ICESat-2 to predict forest above-ground biomass density (AGBD). As ICESat-2 is on a polar orbit, it provides good spatial coverage of boreal forests. The aim of this study is to evaluate the estimation of mean AGBD from ICESat-2 data using a hierarchical modeling approach combined with rigorous statistical inference. We propose a hierarchical hybrid inference approach for uncertainty quantification of the average AGBD of the area of interest estimated directly from a sample of ICESat-2 lidar profiles. Our approach models the errors coming from the multiple modeling steps, including the allometric models used for predicting tree-level AGB. For testing the procedure, we have data from two adjacent study sites, denoted Valtimo and Nurmes, of which Valtimo site is used for model training and Nurmes for validation. The ICESat-2 estimated mean AGBD in the Nurmes validation area was 65.7 ± 1.9 Mg/ha (relative standard error of 2.9%). The local reference hierarchical model-based estimate obtained from wall-to-wall airborne lidar data was 63.9 ± 0.6 Mg/ha (relative standard error of 1.0%). The reference estimate was within the 95% confidence interval of the ICESat-2 hierarchical hybrid estimate. The small standard errors indicate that the proposed method is useful for AGBD assessment. However, some sources of error were not accounted for in the study and thus the real uncertainties are probably slightly larger than those reported.202
Sporadic cases of chronic wasting disease in old moose : an epidemiological study
Get PDFTransmissible spongiform encephalopathies or prion diseases comprise diseases with different levels of contagiousness under natural conditions. The hypothesis has been raised that the chronic wasting disease (CWD) cases detected in Nordic moose (Alces alces) may be less contagious, or not contagious between live animals under field conditions. This study aims to investigate the epidemiology of CWD cases detected in moose in Norway, Sweden and Finland using surveillance data from 2016 to 2022.
In total, 18 CWD cases were detected in Nordic moose. All moose were positive for prion (PrPres) detection in the brain, but negative in lymph nodes, all were old (mean 16 years; range 12–20) and all except one, were female. Age appeared to be a strong risk factor, and the sex difference may be explained by few males reaching high age due to hunting targeting calves, yearlings and males.
The cases were geographically scattered, distributed over 15 municipalities. However, three cases were detected in each of two areas, Selbu in Norway and Arjeplog-Arvidsjaur in Sweden. A Monte Carlo simulation approach was applied to investigate the likelihood of such clustering occurring by chance, given the assumption of a non-contagious disease. The empirical P-value for obtaining three cases in one Norwegian municipality was less than 0.05, indicating clustering. However, the moose in Selbu were affected by different CWD strains, and over a 6 year period with intensive surveillance, the apparent prevalence decreased, which would not be expected for an ongoing outbreak of CWD. Likewise, the three cases in Arjeplog-Arvidsjaur could also indicate clustering, but management practices promotes a larger proportion of old females and the detection of the first CWD case contributed to increased awareness and sampling.
The results of our study show that the CWD cases detected so far in Nordic moose have a different epidemiology compared to CWD cases reported from North America and in Norwegian reindeer (Rangifer tarandus tarandus). The results support the hypothesis that these cases are less contagious or not contagious between live animals under field conditions. To enable differentiation from other types of CWD, we support the use of sporadic CWD (sCWD) among the names already in use.202
Viljelykasvien geenivarat : Suojelu, säilytys ja kestävä käyttö
Get PDFTämän julkaisun tarkoituksena on esitellä monipuolisesti viljelykasvien geenivarojen ympärillä tehtyä työtä nyt kun kansallinen kasvigeenivaraohjelma on toiminut kaksi vuosikymmentä. Julkaisu koostuu eri asiantuntijoiden kirjoituksista, joita pyydettiin sekä kansallisen kasvigee-nivaraohjelman omilta toimijoilta Lukesta, että useilta muilta kasvigeenivaroja hyödyntäviltä tahoilta ja asiantuntijoilta. Kirjoitukset käsittelevät geenivarojen säilytystä, tutkimusta, kestävää käyttöä ja saatavuutta.
Kansallinen kasvigeenivaraohjelma on osa Suomen maa-, metsä- ja kalatalouden kansallista geenivaraohjelmaa, jota koordinoi Luonnonvarakeskus (Luke). Kasvigeenivaraohjelman taus-tana ovat kansainväliset sitoumukset ja niiden toimeenpano Suomessa. Luke säilyttää kasvullisesti lisättävien puutarhakasvien kansalliset geenivarakokoelmat. Kokoelmia on vuosien varrella kartutettu ja niiden monimuotoisuutta arvioitu. Myös geenivarojen hyödyntämistä ja kestävää käyttöä on pyritty lisäämään yhteistyössä alan toimijoiden kanssa. Säilymisen varmuutta on kehitetty sekä kryosäilytyksen menetelmin, että kehittämällä yhteistyöhön perustuvaa varmuussäilyttäjäverkostoa.
Pohjoismainen geenivarakeskus NordGen toimii kaikkien Pohjoismaiden yhteisenä siemengeenipankkina ja verkottaa pohjoismaisia geenivaratoimijoita. Esimerkiksi viljelykasvien luon-nonvaraisten sukulaislajien geenivarojen suojelun tietopohjaa on viime vuosina rakennettu monivuotisessa pohjoismaisessa hankeyhteistyössä. Tiedonhallintaa on viime vuosina kehitetty muun muassa viemällä kansallisesti ylläpidettävien kasvigeenivarojen tietoja NordGenin GenBis-tietojärjestelmään. Kansallisen kasvigeenivarakokoelman kasvien parempaa saatavuutta ja luovutuskäytäntöjä on kehitetty kansainvälisen kasvigeenivarasopimuksen mukaisesti.
Kansainvälinen yhteistyö on muutenkin ollut merkittävässä roolissa ohjelma työssä. Suomen asiantuntijat ovat olleet hyvin edustettuina Euroopan kasvigeenivaratoimijoiden verkostossa, jonka hankkeissa kasvigeenivarojen suojelua on kehitetty laajemmassa eurooppalaisessa ke-hyksessä. Kansallisen kasvigeenivaratyön edistymisestä raportoidaan säännöllisesti Yhdistyneiden kansakuntien Elintarvike- ja maatalousjärjestö FAO:lle.
Kasvigeenivarakokoelmien monimuotoisuuden kattavuus, suojelumenetelmien kehittäminen ja säilytyksen kustannustehokkuuden lisääminen ovat jatkuvasti tärkeitä kehityskohteita. Lisää tutkimusta ja yhteistyötä tarvitaan, jotta geenivaroja kyetään tulevaisuudessa hyödyntämään mahdollisimman hyvin kestävän maa- ja puutarhatuotannon hyväksi.202
Root growth dynamics and biomass input of four over-wintering herbaceous crops in boreal conditions
Get PDFRoot growth of winter wheat (Triticum aestivum L.), winter rye (Secale cereale L.), red clover (Trifolium pratense L.), and timothy (Phleum pratense L.) was recorded to evaluate the environmental potential of over-wintering crops in a Nordic agroecosystem. In a field experiment on Aquic Haplocryoll soil, root intensities (number of roots/area) were measured to 50 cm depth by minirhizotron microvideo camera technology over a two -year period (21 recording sessions). At anthesis, root biomass and morphological parameters were measured by destructive soil sampling and image analysis of washed roots. Winter cereal roots reached 50 cm depth as soon as the autumn of the seeding year. For both post-seeding years, timothy roots developed the most intensively in spring, while red clover had higher root intensity than timothy in late autumn. At anthesis, the crops were ranked timothy > red clover > winter wheat > winter rye according to root length density, surface area density, and biomass. Based on S:R ratios, red clover appears to offer the most intense carbon sink at 0–60 cm soil depth. Over-wintering crops had living roots in the subsoil both in late autumn and early spring, indicating potential to plant available nutrient uptake outside the growing season of annual crops.202
Trade-offs between nutrient export, greenhouse gas balance and financial performance in continuous cover and rotation forestry in drained peatlands in northern Finland
Get PDFBoreal peatlands comprise one of the largest terrestrial carbon pools, provide a variety of ecosystem services,and are important for biodiversity. The characteristic multifunctionality of peatland forests calls for research that is able to assess trade-offs between marketed (timber) and non-marketed (water quality, greenhouse gas balance) public goods. Once the trade-offs are revealed, it becomes feasible to pursue sustainable forest management. An openly available database was used to derive an empirical dataset representing a miniature of the Kiiminkijoki catchment in northern Finland, which was used for stand-level simulations (Motti stand simulator) and landscape-level optimisation in drained peatland forests. For each initial state, stand projections were simulated for rotation forestry (RF) and continuous cover forestry (CCF) management. The rationale was to investigate trade-offs between nutrient export, greenhouse gas balance and net present value (NPV). The cost efficiency of reducing greenhouse gas emissions and nutrient export was calculated by optimising forest management (both RF and CCF) within the Kiiminkijoki catchment. The results suggested that applying both RF and CCF in drained peatlands constitutes a highly cost-effective way to reduce greenhouse gas emissions, the cost range being € ~5–20 per tonne of CO2. However, the nitrogen equivalent (NE) cost of reducing nutrient export tends to be quite high (€ 17–58 kg-1) compared to values for mineral soils provided by existing literature.202
Temporal increase in migratoriness and increasing male bias among residents in partially migrating Swedish sparrowhawks Accipiter nisus
Get PDFPartial migrants have populations consisting of both migratory and resident individuals. These migrants and residents experience unequal ecological conditions during winter and the underlying factors driving their decision to stay on their breeding grounds or to migrate remain debated—both from the viewpoint of populations and individuals. Here, we studied partial migration in a small raptor, the Eurasian Sparrowhawk (Accipiter nisus), from two different but interconnected perspectives: 1) explaining the patterns and variation in the ratio of migrants to residents (migratoriness) at the population level and 2) revealing how age and sex may affect the individual decision to be migratory or resident. We used citizen observation data over four decades to explore the temporal and spatial variation in the age and sex ratio of wintering resident sparrowhawks in Sweden. We found that the migratoriness unexpectedly increased with higher annual temperatures and showed long-term trend across the study period. Also, this migrant-to-resident ratio increased with smaller winter prey abundance. The average winter sex ratio was male-biased and became increasingly so over the years. We suggest that residency benefits territory-establishing males as early presence gives a competitive advantage in obtaining high-quality territories. Moreover, the distribution of overwintering individuals (regardless of sex) moved gradually northwards as the winter progressed, suggesting that smaller-scale migration occurs among the resident fraction of the population. These results provide suggestions for the underlying drivers and regulation of partial migration.202