Нелесные земли: горные тундры - 18 га, гольцы - 1 габ мари и верховая тундра - 49 га, галечники - 7 га, и т.д.

Вот такое определение я нашла:
Мари (единственное число — марь), болотистые пространства, покрытые редкостойными угнетёнными лиственничными лесами, перемежающимися с участками безлесных болот (главным образом в Восточной Сибири и на Дальнем Востоке).

То, что есть в Мультитране, мне не подходит - там говорится про вид трав. Как же будут такие земли по-английски?

A type of wetland that does not accumulate appreciable peat deposits and is dominated by herbaceous vegetation. Marshes may be either freshwater or saltwater and tidal or nontidal. (Source: EPA/Great Lakes National Program Office: Glossary of Great Lakes Ecosystem Management Terms Term Detail)

An periodically inundated area of low ground having shrubs and trees, with or without the formation of peat.(Source: BJGEO) (Source: European Environment Agency (EEA), European Topic Centre on Catalogue of Data Sources (ETC/CDS): General Multilingual Environmental Thesaurus Term Detail)

wetland
An area that is regularly saturated by surface water or groundwater and is characterized by a prevalence of vegetation that is adapted for life in saturated soil conditions (eg, swamps, bogs, fens, marshes, and estuaries).
www.epa.gov/glnpo/rptcong/1994/glossary.htm

A general term applied to land areas which are seasonally or permanently waterlogged, including lakes, rivers, estuaries, and freshwater marshes; an area of low-lying land submerged or inundated periodically by fresh or saline water.
biology.usgs.gov/s+t/SNT/noframe/zy198.htm

Includes permanently or intermittently wet areas, shallow water, and land water margins that support a natural ecosystem of plants and animals that are adapted to wet conditions
www.ebop.govt.nz/Coast/Glossary-of-terms.asp

Land that is transitional between aquatic and terrestrial ecosystems and is covered with water for at least part of the year.
commpres.env.state.ma.us/content/glossary.asp

Those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.
www.ieca.org/Resources/Reference/DefinitionsTZ.asp

Any area in which the water table stands near, at, or above the land surface for at least part of the year. Such areas are characterized by plants that are adapted to wet soil conditions.
www.mwdoc.com/glossary.htm

A land inclusion that has a predominance of hydric soils; is inundated or saturated by surface or groundwater at a frequency and duration sufficient to support a prevalence of hydrophytic vegetation; and supports a prevalence of such vegetation under normal circumstances.
techreg.sc.egov.usda.gov/NTE/TSPNTE2/def_glossary.html

land (marshes or swamps) saturated with water constantly. These lands mostly are near our coastlines or other areas of large amounts of water.
www.recycle4schools.org.uk/ecodict_w.htm

а я, посмотрев на определения Answers.com, пока выбрала слово bog... там похоже расписано про кустарники и редкие деревья...

Спасибо всем за помощь