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Table 3 Quantitative data on grazing/browsing pressure (herbivore density and biomass)

From: Manipulating ungulate herbivory in temperate and boreal forests: effects on vegetation and invertebrates. A systematic review

 

Herbivore density (no. of animals/km2)

Study type

Range

Median

No. of studies

 All studies

0.7–130

20

84

 Wild ungulates (any intervention)

0.7–130

15.5

73

 Livestock (any intervention)

1.2–123

25

14

 Fencing (exclusion/enclosure, any species)

0.7–125

16.3

77

 Sustained/abandoned/resumed livestock grazing

25–50

45

3

 

Herbivore metabolic biomass (kg/km2)

Study type

Range

Median

No. of studies

 All studies

15–10300

500

84

 Wild ungulates (any intervention)

15–10300

465

73

 Livestock (any intervention)

114–5500

2000

14

 Fencing (exclusion/enclosure, any species)

15–3600

480

77

 Sustained/abandoned/resumed livestock grazing

2750–5500

5000

3

  1. The table is based on study averages (presented as ranges and medians) of grazing/browsing pressure in areas exposed to high herbivory (e.g. unfenced control plots in fencing studies). Reported herbivore densities have been converted by us to metabolic biomass (see Additional file 6), and livestock densities have been adjusted for length of grazing season (see "Methods"). Note that quantitative data on grazing pressure were available for only three of the 17 studies of sustained/abandoned/resumed grazing by livestock (or reindeer) included in the review