Ecological Sites on Rangeland
description
Transcript of Ecological Sites on Rangeland
Ecological Siteson Rangeland
Ecological Site definition: Ecological site = kind of land with:
specific physical characteristics (soil, topography, climate)
which differs from other kinds of land in its ability to produce
distinctive kinds and amounts of vegetation
In other words, a kind of land with similar natural potential.
Other stratification systems can be an have been used to described rangelands.
Ecological sites vary in kind and amount of vegetation
(Example 1)
(Example 2)
(Example 3)
(Example 4)
Ecological Sites – Based on Soil Soil affects the type of plants that
grow on the land. Therefore, soil maps usually form
the basis for maps of ecological sites.
Ecological Site Descriptions – can be found by starting with soil maps in the Web Soil Survey
Ecological Site Descriptions Ecological Site Descriptions (ESD)
are reports that describe the: Biophysical properties of ecological sites
Physical, Climatic, Soil and Vegetation Vegetation and surface soil properties of reference
conditions a) Pre-European vegetation and historical range of variation (in
the United States) b) Proper functioning condition or potential natural vegetation
Ecosystem services provided by the ecological site and other interpretations
Important ConceptsIn Dividing the Landscape
Spatial scale – what is a site?
Temporal scale- how does change occur?
Geographic areas with similar soils
Similar landscape patterns
Groups of Ecological Sites that share landscapes
Intermingled ecological sites or single site
Individual representative of the site
An observation of plant-soil relationships
Regions with similar climate, land use
LAND RESOURCE REGIONS
35
43B
3
42 133A
8
5
30136
54
72
58A
40
25
48A
52
73
29
47
28A
23
6534A
133B103
98
36
56
38
17
143
43A
116A
140
27
131A
112
53B
41
28B 147
77C
125
105
7
58B
153A
67B
78C
127
55B
22A
69
80A
126
2
78B
109
21
31
24
55A
86A
102A
104
7175
90A
74
70C
139
55C
85
95B
119130B
106107B
121
63A32
79
53A
12143
81B
94A
43A
77A
102C
113
150A
Non-native grass invasion,increased fire frequency,loss of native woody plants
Drought-triggeredforest dieback
Non-native grass invasion,altered surface hydrology, reduced productivity
Perennial grass loss, soil erosion, native woody plant dominance
Nonnative woody plant invasion
Native woody plant thickening, reduced fire frequency
MLRAs distinguish broad differences in potential and types of ecological dynamics
Major Land Resource Areas USDA NRCS
Loamy soil (active piedmont)Susceptible to water erosion andgrass loss: vulnerable/restorable
Clayey soil (basin floor)Receives water and sediment: low risk
Limestone Grass protected byrocks, higher rainfall,good water capture: low risk
Soil mapping units of the Jornada Basin (15 km)
Gravelly soil (shallow, relict piedmont)Surface soil water limited, high risk for grass loss and erosion: vulnerable/restorable
Sandy soil (relict basin floor)Erodible surface soils once grasses removed: vulnerable/hard to restore
The LRU (local climate, soils and geology) refines and supports MLRA concepts
From Bestelmeyer et al 2010
Within LRUs are clusters of sites with similar parent material,but differing in landscape position
Each site has a typical soil profile
An ecological site groups severalsimilar soil map unit components
Map unit/components Ecological siteST: Stellar association 40% Stellar clay loam, 0-3% slopes = Clayey40% Stellar clay loam, 0-3% slopes, flooded = Bottomland20% other inclusions
BK: Berino-Dona Ana association50% Berino fine sandy loam, 1-5 % slopes = Sandy30% Dona Ana fine sandy loam, 1-5% slopes = Sandy20% other inclusions
OP: Onite-Pajarito association40% Onite loamy sand, 1-4% slopes = Sandy30% Pajarito fine sandy loam, 0-5% slopes = Sandy15% Pintura fine sand, 0-5% slopes = Deep sandy15% other inclusions
A soil map unit can contain more than one ecological site because map units may contain components
The utility of Ecological Sites is based on the ability to systematically stratify the landscape according to varying ecological potential
Applications of Ecological Sites and Ecological Site Descriptions
Assess the risk of persistent degradation (undesirable change) and take proactive measures to avoid it
Uses of Ecological Sites and Ecological Site Descriptions
Transition (T)
Slow variables and triggersChronic heavy defoliation coupled to multi-year drought events
ThresholdBlack grama grass cover loss to < 3% and inability to recover continuity via vegetative growth
Uses of Ecological Sites and Ecological Site Descriptions
Specify constraints to desired ecosystem change, estimate their probability of occurrence and devise contingencies
Design and interpret monitoring based on expected responses to management or climatic changes.
Uses of Ecological Sites and Ecological Site Descriptions
Ecological Site Information Applications at Larger (LRU, MLRA and LRR) Scales Narratives for states and communities
contain indicator values and management strategies to promote resilience. Knowledge
of the amounts and spatial distribution of these requirements can inform policies and
programs
ECOLOGICAL STATE
ECOLOGICAL SITE
CLIMATE
SOIL PROPERTIES
LANDSCAPE POSITION
GEOMORPHOLOGY
ECOSYSTEM SERVICES
PROVISIONINGfood, fibre
SUPPORTINGwater cycling, nutrient cycling, primary production
CULTURALeducational, recreation, heritage
REGULATINGclimate, waste control, pollinationHI
STO
RICA
L AN
D CU
RREN
T M
ANAG
EMEN
T
PRIO
R EC
OSY
STEM
SER
VICE
S
FUTU
RE E
COSY
STEM
SER
VICE
S
From Brown and MacLeod 2011
Land Use and Land Management Changes Can Alter Ecosystem Services Regardless of Land Use
Land cover/use classifications are increasingly useless in making policy decisions
people change land use frequently
ecological processes are much more complex and variable than a land use category
resistance and resilience are vital to predicting ecosystem behavior
landscape scale models require ecological process information to allow sites to interact
http://www.youtube.com/watch?v=Eh96zARD-Io