. Bonner zoologische Monographien. Zoology. 32. : Inner Hmialayas. Upper Kali Gandaki Valley, forest cleaiing Thaksang, Pinus wallichiana, Abies spectabilis forest, abandoned and overgrown terraces with hedges of Rosa, Berberis, Spiraea, Ribes. Viburnum, locally small Arundinaria bamboo, 3150 m, Mustang Distr., 1970 J. Martens. tation is outside the range of strong monsoon influence. Species of open country are affected in just the same way. In these valleys there is a relationship between precipitation and al- titude ("regional reduction of the lower boundary of vertical dis
. Bonner zoologische Monographien. Zoology. 32. : Inner Hmialayas. Upper Kali Gandaki Valley, forest cleaiing Thaksang, Pinus wallichiana, Abies spectabilis forest, abandoned and overgrown terraces with hedges of Rosa, Berberis, Spiraea, Ribes. Viburnum, locally small Arundinaria bamboo, 3150 m, Mustang Distr., 1970 J. Martens. tation is outside the range of strong monsoon influence. Species of open country are affected in just the same way. In these valleys there is a relationship between precipitation and al- titude ("regional reduction of the lower boundary of vertical distribution"), but the inter- mediate factors that control it are unknown. Striking examples are: Phoenicurus ochniros, Pyrrhocorax pyrrhocorax, P. graciilus, Parus ater, Carpodaciis eiythrinus, Hodgsoniiis phae- niciiroides, Phylloscopus ajfinis, Ph. trochiloides, Certhia familiaris, Tarsiger cyanurus. b. In the W-E direction, the forest vegetation of the Inner Valleys exerts just as strong an influence on the fauna. It channels the immigration of dry-adapted species from the W Hi- malayas (), locally on a very small scale, into sheltered parts of the C Himalayas im- mediately adjacent to monsoon regions. Only where protected from rain in these Inner Valleys can plant communities with Abies pindrow, Cednis deodara, Picea smithiana and Cupressus torulosa today form established islands, with the "appropriate" fauna: towards the south this fauna is blocked by high precipitation, and towards the north by Tibetan ari- dity and treelessness. The individual tree species that form stands here, hke the bird spe- cies, are distributed one after another towards the west. The insular nature of these areas, limited to naiTOwly circumscribed parts of the valleys, is striking in the eastward direction. For instance, Certhia himalayana has reached the isolated dry valley of Manang (N of An- napurna), while Parus rufonuchalis has gone only as far as Thakkhola (Figs. 30, 31).
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