Current and expected changes in global climate are major threat for biological diversity affecting individuals, communities and ecosystems. However, there is no general trend in the plants response to the climate change. The aim of present study was to evaluate impact of the future climate changes on the distribution of holomycotrophic orchid species using ecological niche modeling approach. Three different scenarios of future climate changes were tested to obtain the most comprehensive insight in the possible habitat loss of 16 holomycotrophic orchids. The extinction of Cephalanthera austiniae was predicted in all analyses. The coverage of suitable niches of Pogoniopsis schenckii will decrease to 1–30% of its current extent. The reduction of at least 50% of climatic niche of Erythrorchis cassythoides and Limodorum abortivum will be observed. In turn, the coverage of suitable niches of Hexalectris spicata, Uleiorchis ulaei and Wullschlaegelia calcarata may be even 16–74 times larger than in the present time. The conducted niche modeling and analysis of the similarity of their climatic tolerance showed instead that the future modification of the coverage of their suitable niches will not be unified and the future climate changes may be not so harmful for holomycotrophic orchids as expected.

The location of possible glacial refugia of six Apostasioideae representatives is estimated based on ecological niche modeling analysis. The distribution of their suitable niches during the last glacial maximum (LGM) is compared with their current potential and documented geographical ranges. The climatic factors limiting the studied species occurrences are evaluated and the niche overlap between the studied orchids is assessed and discussed. The predicted niche occupancy profiles and reconstruction of ancestral climatic tolerances suggest high level of phylogenetic niche conservatism within Apostasioideae.

A taxonomic synopsis of the orchid genus Habenaria in New Guinea and adjacent islands is presented. We confirmed the occurrence of 27 Habenaria species in study area. Sixteen of these are endemic and were not so far found outside New Guinea. Morphological characteristics and illustrations of floral segments of taxa are presented. One new species of Habenaria is described. Four neotypes are selected. An updated key to species groups and species occurring in the study area is provided. The importance of diagnostic floral characters in Habenaria is discussed.

Abstract.A new species of the genus Habenella Small is described based on material collected in Nepal. The novelty resembles H. anomaliflora Kurzweil & Chantanaorr., from which it differs by the presence of a single leaf, oblong-lanceolate lip, ovate lateral sepals with a somewhat oblique base, and oblong-lanceolate petals. An identification key for representatives of Habenaria s.l. reported from Nepal is included.

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