Conservation Ecology: Linkages between water vapor flows, food production and terrestrial ecosystem services: Table 1

Table 1. Total water vapor estimates with the classification of biomes and vegetation subgroups.

Biome	Vegetation subgroups	Climatic zone	Land surface ^a	n^k	Actual evapotranspiration (mm/yr)			Water vapor estimates (km³/yr)
			1000 km²		Mean	Low	High	Mean	Low	High
Forest, woodlands	taiga	boreal	11,560	3	401	380	420	4636	4393	4855
	predominantly coniferous	temperate	3500	4	487	395	580	1705	1383	2030
	predominantly deciduous	temperate	8500	4	729	588	964	6199	4998	8194
	woodland/woody savannah	temperate	5200	3	416	300	530	2165	1560	2756
	forest, dry/deciduous/seasonal	tropical/subtropical	7400	2	792	783	800	5857	5794	5920
	forest, wet	tropical/subtropical	5300	3	1245	880	1493	6600	4664	7913
	savannah/woodland, dry	tropical/subtropical	12,700	2	882	870	894	11,201	11,049	11,354
	savannah/woodland, wet	tropical/subtropical	1300	3	1267	1100	1500	1647	1430	1950
Subtotal								40,009	35,271	44,972
Wetland	bog	boreal	651	3	221	200	260	144	130	169
	bog	temperate	488	4	674	456	1020	329	223	498
	swamp	temperate	41	3	843	670	720	35	27	30
	swamp	subtropical	16	5	1127	930	1277	18	15	20
	swamp ^b	tropical	508	1	1656	1408	1904	841	715	967
Subtotal								1366	1110	1684
Grasslands	cool grassland	mostly temperate	6940	16	410	130	633	2843	900	4393
	mountainous grassland	temperate	650	4	655	430	951	426	280	618
	warm and hot grassland	mostly tropical	17,300	7	599	403	862	10,356	6967	14,913
	mountainous grassland ^c	tropical	650	1	600	402	798	390	261	519
	dry shrubland	tropical	4000	2	270	225	315	1080	900	1260
Subtotal								15,095	9308	21,702
			Production (10³Mg/yr) ^d	n	Water Use Efficiency (m³/Mg) ^e
Croplands	cereals, grain	temperate	790,476	15	1309	539	2643	1095	564	1919
	cereals, grain	tropical	625,409	10	1438	591	4369	764	555	1178
	cereals, total DM ^f	temperate	4011	19	438	240	646	56	31	83
	cereals, total DM ^f	tropical	664,404	3	331	271	372	235	217	247
	cotton lint		18,509	3	5454	4227	6313	101	78	117
	cotton seed		86,925	1	2083	1667	2500	181	144	217
	fibers		5541	4	574	278	870	3	2	5
	forage		725,032	19	934	172	2810	641	249	1403
	fruit	temperate	208,348	2	269	163	375	58	34	78
	fruit	tropical	232,748	3	259	150	350	60	35	81
	natural rubber/gums		6088	2	30,137	29,167	31,108	183	178	189
	nuts ^g		6929	1	415	200	1080	2	1	6
	oil-bearing crops	temperate	35,454	3	1892	1530	2117	64	54	72
	oil-bearing crops	tropical	55,225	2	3083	2667	3500	71	70	92
	oil palm ^h		6,604,000 km²	1	1500 mm	1250 mm	1750 mm	242	212	278
	pulses, dry seed	temperate	43,493	3	3355	1731	5833	157	75	197
	pulses, dry seed	tropical	166,338	5	1866	1250	3003	283	214	370
	pulses, green seed	temperate	9326	2	1149	583	1714	12	5	16
	rice		540,838	4	1099	839	1404	594	454	759
	roots and tubers	temperate	558,137	7	286	139	402	144	94	217
	roots and tubers ^g	tropical	330,786	1	616	369	1299	204	122	430
	roots, tubers for fodder ^f	temperate	11,105	8	326	157	616	4	2	7
	spices ⁱ		4091	0	1000	800	1500	4	3	6
	stimulant crops		791	3	4515	2083	6983	33	28	74
	sugar cane		1,120,898	3	123	100	163	138	112	182
	vegetables ^j		549,683	6	147	35	500	75	22	242
Subtotal								5404	3552	8427
Total								61,879	49,280	76,800

^a Land surfaces for forests and grasslands are derived from Olson et al. (1983); land surfaces for wetlands are from Matthews (1983).

^b Low/high values are based on the mean +/- 15%.

^c Low/high values are based on the mean +/- 33%, based on the average standard deviation of the other subgroups in grasslands.

^d Production data are from the FAO (Faostat 1997).

^e Note that only the aggregate average WUE values for similar crops are presented in Table 1. For example, the WUE values and the water vapor estimates for cereals/temperate in Table 1 are derived from individual values for each major cereal (wheat, barley, oats, rye, and buckwheat).

^f The WUE was calculated based on the total dry matter yield.

^g The mean WUE comes from only one article; the low and high are the variations within that article.

^h For oil palms, which are harvested on the same area for oil, kernels, and fruit, the total freshwater used was calculated by

area harvested = oil produced (Mg)/production of oil (Mg/ha)
total water vapor used = area harvested (km²) x ET from palm stands (m)

Palm oil production (6,603,778 Mg) was collected from the FAO (Faostat 1997). The production was assumed to be 1.75 Mg/ha (Mémento de l´Agronome 1984). The ET from palm stands is 1500 mm (Jackson 1989). The variation of ET was assumed to be 125 mm. The minimum and maximum calculation for oil palm was therefore based on the ET rates of 1375 mm and 1725 mm. The same values were used for low/high calculations.

ⁱ Spices is a small group, covering only about 0.045% of the total global area harvested each year (Faostat 1997). There is also a large variation in species composition, as well as in parts of the plant used for production measurement. The WUE was, therefore, based on a qualified assumption. The WUE was assumed to be 1000 m³/Mg. The minimum was assumed to be 800 m³/Mg, the maximum as 1500 m³/Mg, and the standard deviation as 200 m³/Mg. Spices are often just a small part of a plant, why the WUE will be higher if the whole plant is considered.

^j For vegetables that were produced as feed, the WUE was calculated based on the ”grain” yield of that specific crop or group of crops.

^k The number of references.

^a	Land surfaces for forests and grasslands are derived from Olson et al. (1983); land surfaces for wetlands are from Matthews (1983).
^b	Low/high values are based on the mean +/- 15%.
^c	Low/high values are based on the mean +/- 33%, based on the average standard deviation of the other subgroups in grasslands.
^d	Production data are from the FAO (Faostat 1997).
^e	Note that only the aggregate average WUE values for similar crops are presented in Table 1. For example, the WUE values and the water vapor estimates for cereals/temperate in Table 1 are derived from individual values for each major cereal (wheat, barley, oats, rye, and buckwheat).
^f	The WUE was calculated based on the total dry matter yield.
^g	The mean WUE comes from only one article; the low and high are the variations within that article.
^h	For oil palms, which are harvested on the same area for oil, kernels, and fruit, the total freshwater used was calculated by area harvested = oil produced (Mg)/production of oil (Mg/ha) total water vapor used = area harvested (km²) x ET from palm stands (m) Palm oil production (6,603,778 Mg) was collected from the FAO (Faostat 1997). The production was assumed to be 1.75 Mg/ha (Mémento de l´Agronome 1984). The ET from palm stands is 1500 mm (Jackson 1989). The variation of ET was assumed to be 125 mm. The minimum and maximum calculation for oil palm was therefore based on the ET rates of 1375 mm and 1725 mm. The same values were used for low/high calculations.
ⁱ	Spices is a small group, covering only about 0.045% of the total global area harvested each year (Faostat 1997). There is also a large variation in species composition, as well as in parts of the plant used for production measurement. The WUE was, therefore, based on a qualified assumption. The WUE was assumed to be 1000 m³/Mg. The minimum was assumed to be 800 m³/Mg, the maximum as 1500 m³/Mg, and the standard deviation as 200 m³/Mg. Spices are often just a small part of a plant, why the WUE will be higher if the whole plant is considered.
^j	For vegetables that were produced as feed, the WUE was calculated based on the ”grain” yield of that specific crop or group of crops.
^k	The number of references.