TOLERATION OF TRAFFIC BY VEGETATION - LIFE FORM CONCLUSIONS AND SUMMARY EXTRACTS FROM A COMPREHENSIVE DATA-BASE

An exhaustive search of the literature for foot and vehicle traffic im pacts on vegetation has yielded more than 400 citations, two thirds of which held sufficient detail to be usefully distilled into a personal -computer data base. A total of 1444 individual observations involving 737 species that were trampled are included. Compromises were made in the depth of entry detail and to allow comparability among data. Inco nsistent, generally short-term, experimental practices disallowed form al statistical analyses. Within those constraints, graminoids emerged with the highest mean resistance and resilience among life-forms. Clim bers and cactoids ranked lowest in these categories. The herbaceous, t ypically broader-leaved (forb) life-form appeared most likely to suffe r immediate losses. Shrubs and trees had the longest-lasting decreases in diversity following traffic impact. Ail life-forms had sensitive s pecies. The greatest general species and individual plant losses take place in the first few passes by feet, wheels, or tracks. Plant and so il damage increases with the amount of weight and power applied. Great er soil moisture and/or deeper overstory shading magnify those impacts . Additional precepts may become apparent to data-base users through i ncreased ease in making comparisons.