Soils of a Mediterranean hot spot of biodiversity and endemism (Sardinia, Tyrrhenian Islands) are inhabited by pan-European, invasive species ofHypocrea/Trichoderma

We have used a Mediterranean hot spot of biodiversity
(the Island of Sardinia) to investigate the impact
of abiotic factors on the distribution of species of the
common soil fungusTrichoderma. To this end, we
isolated 482 strains ofHypocrea/Trichodermafrom 15
soils comprising undisturbed and disturbed environments
(forest, shrub lands and undisturbed or extensively
grazed grass steppes respectively). Isolates
were identified at the species level by the oligonucleotide
BarCode forHypocrea/Trichoderma (TrichOKEY), sequence similarity analysis (TrichoBLAST)
and phylogenetic inferences. The majority of the
isolates were positively identified as pan-European
and/or pan-globalHypocrea/Trichodermaspecies
from sectionsTrichodermaandPachybasium, comprisingH. lixii/T. harzianum, T. gamsii, T. spirale, T.
velutinum, T. hamatum, H. koningii/T. koningii, H.
virens/T. virens, T. tomentosum, H. semiorbis, H.
viridescens/T. viridescens, H. atroviridis/T. atroviride,
T. asperellum, H. koningiopsis/T. koningiopsis and
Trichodermasp. Vd2. Only one isolate represented
a new, undescribed species belonging to the
Harzianum–Catoptron Clade. Internal transcribed spacer sequence analysis revealed only one potentially
endemic internal transcribed spacer 1 allele ofT. hamatum. All other species exhibited genotypes
that were already found in Eurasia or in other
continents. Only few cases of correlation of species
occurrence with abiotic factors were recorded. The
data suggest a strong reduction of nativeHypocrea/
Trichodermadiversity, which was replaced by extensive
invasion of species from Eurasia, Africa and the
Pacific Basin.