Variation in the abundance of fungal endophytes in fescue grasses along altitudinal and grazing gradients

• Epichloë festucae, a common fungal symbiont of the genus Festuca (family Poaceae), can provide its host plant with protection against herbivores. However, infection might also be associated with a cost to its host plant. We examined the distribution of Epichloë festucae infection in natural populations of three fescue grasses, Festuca rubra, F. ovina and F. vivipara, on mountains in northern Sweden to determine whether infection frequency varied with reindeer Rangifertarandus grazing pressure and altitude. Two differently-scaled approaches were used: 1) infection frequency was measured at a local scale along ten elevational transects within a ca 400 km2 area and 2) infection frequency was measured on a regional scale along elevational transects on 17 mountains classified as having a history of high or low reindeer grazing pressure. Mean infection frequencies in F. rubra were 10% (vegetative tillers at a local scale), and 23% (flowering culms at a regional scale), and in F. ovina they were 13% (local scale) and 15% (regional scale). Endophyte infection frequency in F. vivipara, was, on average, 12% (local scale) and 37% (regional scale). In F. rubra, infection decreased significantly with increasing altitude at both the local and regional scale, and was positively correlated with grazing pressure. In F. ovina, an opposite trend was found at the regional scale: infection frequency increased significantly with increasing altitude, while no discernible distribution pattern was observed at the local scale. No elevational trends were observed in infection of F. vivipara. These patterns in the distribution of endophyte-infected grasses in non-agricultural ecosystems may be explained by both biotic (grazing) and abiotic factors (altitude). Differences in ecology and life history of the studied grass species may also be of importance for the different results observed among species.

Subject headings

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Keyword

Vertebrata

Mammalia

Ungulata

Artiodactyla

Spermatophyta

Angiospermae

Monocotyledones

Gramineae

Thallophyta

Fungi

Ascomycetes

Environmental factor

Europe ; Abiotic factor

Rangifer tarandus

Festuca rubra

Browsing

Sweden

Mountain

Natural population

Costs ; Infection

Herbivorous

Protection

Host plant

Symbiont

Altitude

Vertical gradient

Herbaceous plant

Endophyte

Ecological abundance

Biology

Biologi

Publication and Content Type

ref (subject category)

art (subject category)