Traditional plant functional groups explain variation in economic but not size-related traits across the tundra biome.

AIM: Plant functional groups are widely used in community ecology and earth system modelling to describe trait variation within and across plant communities. However, this approach rests on the assumption that functional groups explain a large proportion of trait variation among species. We test whether four commonly used plant functional groups represent variation in six ecologically important plant traits. LOCATION: Tundra biome. TIME PERIOD: Data collected between 1964 and 2016. MAJOR TAXA STUDIED: 295 tundra vascular plant species. METHODS: We compiled a database of six plant traits (plant height, leaf area, specific leaf area, leaf dry matter content, leaf nitrogen, seed mass) for tundra species. We examined the variation in species-level trait expression explained by four traditional functional groups (evergreen shrubs, deciduous shrubs, graminoids, forbs), and whether variation explained was dependent upon the traits included in analysis. We further compared the explanatory power and species composition of functional groups to alternative classifications generated using post hoc clustering of species-level traits. RESULTS: Traditional functional groups explained significant differences in trait expression, particularly amongst traits associated with resource economics, which were consistent across sites and at the biome scale. However, functional groups explained 19% of overall trait variation and poorly represented differences in traits associated with plant size. Post hoc classification of species did not correspond well with traditional functional groups, and explained twice as much variation in species-level trait expression. MAIN CONCLUSIONS: Traditional functional groups only coarsely represent variation in well-measured traits within tundra plant communities, and better explain resource economic traits than size-related traits. We recommend caution when using functional group approaches to predict tundra vegetation change, or ecosystem functions relating to plant size, such as albedo or carbon storage. We argue that alternative classifications or direct use of specific plant traits could provide new insights for ecological prediction and modelling.

[Bilateral paralysis of the vocal cords treated with endolaryngeal arytenoidectomy]. / Dobbeltsidig stemmebåndsparese behandlet med endolaryngeal arytenoidektomi.

Bilateral paralysis of the vocal cords is a serious condition in which even slight oedema of the mucosa may endanger the patient's life. Bilateral paralysis of the vocal cords is most frequently due to thyroid operations but intubation, neuritis etc are among the other causes. Tracheostomy is nearly always necessary. In an attempt to render removal of the tracheal cannula possible with retention of vocal function, the authors have performed endolaryngeal arytenoidectomy. This intervention was carried out in 28 patients. In 23 of these the cannula could be removed while various conditions prevented removal of the cannula in the remaining five patients. The authors consider that arytenoidectomy is a good form of treatment of bilateral paralysis of the vocal cords involving only a slight risk. Thereafter, there are good chances for removal of the cannula with simultaneous retention of vocal function.

Nasal complication after transsphenoidal surgery for pituitary pathologies.

A retrospective study was performed to investigate the frequency of nasal complications following sublabial transseptal transsphenoidal surgery for pituitary pathologies. 42 patients were examined. It was noted that more than 50% developed iatrogenic sequelae. It was concluded that a team of neurosurgeons and rhinologists should be established, combining their skills and techniques, to reduce the incidence of iatrogenic sequelae.

Unilateral total deafness as a complication of the measles-mumps-rubella vaccination.

A 7 year old girl developed unilateral total loss of hearing 13 days following MMR vaccination. The live, attenuated mumps-virus component in the virivac vaccine is suspected to be the cause of the injury.