Mineral diversity in wild plants: benefits and bane for moose

Abstract

Ohlson, M. and Staaland, H. 2001. Mineral diversity in wild plants: benefits and bane for moose. -Oikos 94: 442 -454.We studied the mineral nutrition ecology of moose, Alces alces, by a comprehensive examination of concentration levels of 18 elements in browsing plants, and in rumen and distal colon contents, respectively. The plants, in total 14 species, included deciduous and evergreen trees, shrubs, herbs, grasses and aquatic macrophytes. Our study was done in four sites in southern Norway and the plants were sampled in spring, summer, autumn and winter to document seasonal trends. The plants were generally characterized by low concentrations of major elements, very low phosphorus: calcium ratios, and the willow Salix aurita -a preferred browse -had high cadmium concentrations, up to 9 ppm (dry mass). Sodium concentrations in terrestrial plants were significantly under the dietary requirement, while levels were sufficient in aquatic plants, which, however, had high concentrations of toxic heavy metals. We suggest that the moose experience a nutritional dilemma as a strong physiological need for sodium results in an overintake of heavy metals. A selective intake of plants rich in heavy metals was corroborated by high heavy metal concentrations in rumen and distal colon. Over all, the plants were characterized by a marked mineral diversity due to element concentration levels that were highly variable between species and sites. Thus, there is a strong link between plant species diversity and mineral diversity, which has a pivotal role for herbivores. It is concluded that a diversity of plant species is a prerequisite for the mineral diversity that the moose needs to obtain essential minerals, not only in sufficient amounts, but also in physiologically balanced proportions.

Cd, Ni, Pb, and Zn Concentrations in Forest Vegetation and Soils in Maine

“…However, Pb plant tissue concentrations were not different between terrestrial and aquatic habitats (Figure 1c). This result differs from that of Ohlson and Staaland (2001), who documented significantly higher mean concentrations for aquatic compared to terrestrial vegetation concentrations of Cd, Ni, Pb, and Zn in a study that included 14 terrestrial and four aquatic species in Norway. Six of the terrestrial species they sampled were deciduous trees, including downy birch (Betula pubescens) and European aspen (Populus Smith and Siccama (1981) For this study, sample size and standard error are noted in brackets.…”

“…Balsam fir concentrations for all four elements and deciduous tissue concentrations for Ni and Pb at T4 ND were generally comparable to or lower than concentrations reported in previous studies for these and similar tree species in the USA (Friedland & Johnson, 1985;Smith & Siccama, 1981;Van Hook, Harris, & Henderson, 1977) and Scandinavia (Berthelsen et al, 1995;Brekken & Steinnes, 2004;Ohlson & Staaland, 2001). However, deciduous tissue concentrations of Cd and Zn at T4 ND were somewhat higher than similar data for these plant species reported in the literature for remote and non-point source impacted environments (Berthelsen et al, 1995;Brekken & Steinnes, 2004;Chiaranzelli et al, 2001;Ohlson & Staaland, 2001). These differences could reflect soil and parent material differences, but could also be indicative of higher atmospheric deposition rates for Cd and Zn in Maine.…”

“…Trace metal concentrations in forest vegetation are influenced by many factors including specific metal and plant species effects (Berthelsen et al, 1995;Chiarenzelli et al, 2001;Kabata-Pendias, 2001;Ohlson & Staaland, 2001). We compared plant tissue trace metal concentrations among species, between two broad ecosystem types (terrestrial versus aquatic), and between two plant tissue types for deciduous trees (foliage versus branch tip).…”

Use of Natural Licks by Four Species of Ungulates in Northern British Columbia

“…Tannins and other plant secondary compounds are typically high in browse species consumed by moose, with concentrations in individual plants increasing throughout the summer (Bryant and Kuropat 1980). In southern Norway, for example, zoopathological studies on moose documented the occurrence of toxic nephrosis (kidney damage) that may be due to excessive intakes of toxic plant secondary compounds in moose forage (Ohlson and Staaland 2001). Clay ingestion can improve palatability and digestibility for other herbivorous animals by absorbing tannins and potential toxins (Diamond 1999;Johns and Duquette 1991;Smith 1992) and, therefore, may be an important component of lick soil for moose consuming forages in summer when tannin content is elevated (Ayotte et al 2006).…”

Temporal changes in grazing intensity and herbage quality within a Swiss fen meadow

“…Symptoms of P deficiency (e.g. osteoporosis) were found in wild ungulates feeding on herbage with P concentrations between 1 and 2 mg/g (Groot Bruinderink et al 2000;Ohlson and Staaland 2001). Severe P deficiency, leading to behavioural changes such as carnivory, occurred in cattle kept year-round on heathland with an average P concentration of 1 mg/g (WallisDeVries 1996).…”