Findings in 1999 (Gray Ranch)

Findings in 1999 (Gray Ranch)

Bareground

    • 10 percent more (P = .057) bare ground on prairie dog towns than control area, 55% vs 50%, based on line-transect open spaces between plants (140 meter total transect length on town and same on control area).


  • The amount of bare ground represented in small openings tended to be greater off than on dog towns; whereas, the amount of bare ground represented in large openings tended to be greater on than off dog towns.

On or Off
town
Category of bare ground openings, cm		 Relative amount of bare ground as a percentage
of all bare ground
*Statistical probability
On 5 to 10 15 .245
Off 18
On 11 to 20 33 .132
Off 37
On 21 to 30 18 .032
Off 26
On 31 to 40 11 .997
Off 11
On 41 to 50 9.9 .027
Off 4.4
On 51 to 60 6.2 .030
Off 2.3
On 60 to 70 4.7 .018
Off 0.9
On >70 2.6 .220
Off 0.6

* This is the probability that a difference this big between on vs. off towns could exist by chance alone.

  • The percentage of small bare soil openings (0 to 30 cm) were similar on and off dog towns; but, large bare soil openings (>40 cm) tended to be more prevalent on dog towns

On or
Off town
Category of bare ground openings, cm		 Relative number of bare ground as a percentage of all bare ground openings
*Statistical
probability
On 5 to 10 32 .134
Off 37
On 11 to 20 39 .522
Off 37
On 21 to 30 13 .285
Off 16
On 31 to 40 6.0 .601
Off 5.2
On 41 to 50 5.2 .015
Off 1.5
On 51 to 60 2.2 .018
Off 0.5
On 60 to 70 1.5 .0237
Off 0.2
On >70 1.6 .917
Off 1.8

*This is the probability that a difference this big between on vs off towns could exist by chance alone.

    • No difference (P = .570) in bare ground on compared to off prairie dog towns, 33 % vs 35 %, based on point-frame measurement (4200 points on town and 4200 points on control area).

 

Litter and foliar cover:

    • No difference in litter (P = .600) or foliar cover (P = .759) on compared to off prairie dog towns, based on point-frame measurement (4200 points on town and 4200 points on control area). Mean litter cover was 32 % and mean foliar cover was 29 %.

 

Production:

  • Total standing crop of dry matter similar (P = .297) on and off prairie dog towns. Average standing crop was 1421 kg/ha ± 145 kg/ha, respectively.
  • 47 % more (P = ,005) palatable forage off than on prairie dog towns, that is 1084 kg/ha vs 735 kg/ha, respectively.
    • 48 % less blue grama on than off prairie dog towns.


    • 251 % more red threeawn on than off prairie dogs towns.


    • 240% more galletta grass on than off prairie dog towns.


    • 43% less sand dropseed on than off prairie dog towns.


  • About 90% of the production off towns is palatable; only 45 % of vegetation on towns is palatable.

Vegetation structure:

    • No difference in the frequency distribution of vegetation height classes (0 to 5 cm, 6 to 10 cm, 11 to 20 cm, 21 to 30 cm and >30 cm) on prairie dogs towns compared to off prairie dog towns. Structure was similar on prairie dog towns and control area (P = 0.411, 0.336, 0.858, 0.659 and 0.000, respectively)


  • 63% to 66% of vegetation was in the 0 to 5 cm category both on and off prairie dog towns. 81 % to 86 % of vegetation was in the 0 to 10 cm category. 5 cm is about 2 inches; 10 cm is about 4 inches; 30 cm is about 1 foot.

On or Off town
Height category, cm		 Percentage of vegetation in this height category

*Statistical probability
On 0 to 5 66 .411
Off 53
On 6 to 10 20 .336
Off 28
On 11 to 20 12 .858
Off 13
On 21 to 30 1.18 .659
Off 0.91
On >30 0 0
Off 0

* This is the probability that a difference this big between on vs off towns could exist by chance alone.

Carbon/Nitrogen Ratio:

Percentage carbon in three selected grasses on and off towns was similar. Grasses on town contained 12.5 % more nitrogen than grasses off town. The Carbon to nitrogen ratios were significantly lower on vs off towns. A lower C/N ratio indicates more N turnover. Samples were taken 1st 2 weeks of August.


Grass species		 Percentage
Carbon		 Percentage
Nitrogen
Carbon/Nitrogen
Red threeawn – on town
42.33
1.00
45.5
Red threeawn – off town
42.36
  .92
50.3
Galletta grass – on town
41.42
1.13
37.6
Galletta grass – off town
41.84
1.05
43.9
Blue grama – on town
41.63
1.31
32.1
Blue grama – off town
41.86
1.08
39.4