Yngve Rekdal

Senior Adviser (OAP Agreement)

(+47) 959 33 520
yngve.rekdal@nibio.no

Place
Ås O43

Visiting address
Oluf Thesens vei 43, 1433 Ås

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Abstract

Young forest stands and clearcuts in the boreal forest created by modern forestry practices along with meadows of abandoned summer farms may contribute as feeding areas for beef cattle. The patchy distribution and varying quality and diversity of forage on such unimproved lands may affect cattle productivity. Weight gain of 336 beef cows and 270 calves free-ranging during three summer grazing seasons was monitored in boreal forests of southeastern Norway, stocked at either high (0.16 cows ha-1) and low (0.04 cows ha-1) stocking densities. We used linear mixed effect models for assessing intrinsic correlates of weight gain in cows and calves in the two areas. Habitat use and home range size of a subsample of 53 cows were monitored by using GPS collars programmed to log locations at 5 min. intervals during the grazing season. Additional extrinsic correlates of weight gain for the subsampled cows using a linear mixed model were also tested. Average weight gain of beef cows grazing at the low stocking density was positive among cows of early maturing breeds (represented by Hereford) gaining 24 ± 2.8 kg ( ± SE), while cows of late maturing breeds (mainly represented by Charolais) had an average weight loss of 9 ± 8.4 kg. The average weight gain was negative for beef cows of both early (Herefords) and late maturing breeds (mainly represented by Charolais but also Limousin and Simmental) at the high stocking density. Within both breed groups, there was a negative relationship between breed-specific average weight of cows at turnout and weight gain during the grazing period, while a prolonged grazing period was slightly positively related to weight gain. There was no relationship between weight gain and home range size and proportion of grazing habitat for the 53 cows fitted with GPS collars. Higher weight gains in calves of the low compared to the high stocking density area was found. However, there was no breed effect of weight gain in calves. Across study areas, spring-born suckler calves gained more weight than autumn-born calves (92 ± 1.7 kg vs. 65 ± 4.4 kg). Also, there were higher weight gains for springborn bull-calves than spring-born heifers (100 ± 2.4 kg vs. 94 ± 2.2 kg). Overall, the results indicate that it is possible to achieve acceptable weight gains for cattle grazing coniferous forest by finding breeds suitable for these extensive areas and stocking at moderate densities.

Abstract

The Norwegian area frame survey of land cover and outfield land resources (AR18X18), completed in 2014, provided unbiased statistics of land cover in Norway. The article reports the new statistics, discusses implications of the data set, and provides potential value in terms of research, management, and monitoring. A gridded sampling design for 1081 primary statistical units of 0.9 km2 at 18 km intervals was implemented in the survey. The plots were mapped in situ, aided by aerial photos, and all areas were coded following a vegetation type system. The results provide new insights into the cover and distribution of vegetation and land cover types. The statistic for mire and wetlands, which previously covered 5.8%, has since been corrected to 8.9%. The survey results can be used for environmental and agricultural management, and the data can be stratified for regional analyses. The survey data can also serve as training data for remote sensing and distribution modelling. Finally, the survey data can be used to calibrate vegetation perturbations in climate change research that focuses on atmospheric–vegetation feedback. The survey documented novel land cover statistics and revealed that the national cover of wetlands had previously been underestimated.

Abstract

For almost 40 years the Norwegian Forest and Landscape Institute (Norsk institutt for skog og landskap) has mapped vegetation in Norway. In total, just over 10 % of the country’s land area has been mapped, most of which is in the mountain regions. The resultant vegetation maps are the closest Norway has to an ecological map series. Many secondary map themes can be derived from the vegetation map and the digital format allows a wealth of both spatial and temporal GIS-analyses. Accordingly, there are many user groups and topics of interest. During 2009 the aim is to make the institute’s vegetation maps available to all via the Internet in a seamless database.

Abstract

AR18×18 is an area frame survey of land resources in Norway, methodologically linked to the Lucas survey carried out by Eurostat (Eurostat 2003). The purpose of the survey is to establish an unbiased and accurate land cover and land use statistic providing a description of the state of land resources in Norway. The survey will also provide a baseline for future reports regarding changes in land resources – a national land resource accounting system. AR18×18 is based on Lucas (Land use/cover agricultural survey), a European area frame survey carried out in the EU countries by Eurostat. The sampling units of Lucas are points located on the intersections of an 18 × 18 kilometer grid mesh throughout Europe. Each of these points is the centre of a Primary Statistical Unit (PSU) of 1500 × 600 meters. The Lucas survey is carried out on ten sample points scattered within each PSU. The Norwegian modification of Lucas is to add a land cover survey of the whole PSU following the Norwegian system for vegetation and land cover mapping at intermediate scale (1: 20,000). [...]

Abstract

AR18×18 is an area frame survey of land resources in Norway, methodologically linked to the Lucas survey carried out by Eurostat. The method has been adapted to Norwegian conditions. Data accessible through existing mapping systems and public registers are not collected. On the other hand, the survey is strengthened with a land cover mapping component. The purpose of the survey is to establish an unbiased and accurate land cover and land use statistic providing a description of the state of land resources in Norway. The study will also provide a baseline for future reports regarding changes in land resources