ecological sites expanding the concepts and applications of ecological sites joel brown usda nrcs...
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ECOLOGICAL SITES
EXPANDING the CONCEPTS and APPLICATIONS of ECOLOGICAL SITES
Joel BrownUSDA NRCS
Jornada Experimental RangeLas Cruces NM
IMPORTANT POINTS
Changing Conceptual Basis of Ecological Sites
Applications - How can Ecological Sites be used for land management decision-making?
“Arcadia
Ecological Site:
A distinctive kind of land with specific physical characteristics that differs from other kinds of land in its ability to produce a distinctive kind and amount of vegetation, and in its ability to respond to management actions and natural disturbances.
The purpose of an Ecological Site system is to divide landscapes into basic units for study, evaluation, and management
Ecological Site Description (ESD):
Reports with associated data that document the characteristics of an ecological site (including its climate, soils, and state-and-transition model) and the interpretation of its properties related to use and management.
Ecological Site History:
The site concept has undergone major revisions since its original development:
1. Time: A shift from linear, predictable dynamics to an approach based on nonequilibrium dynamics (probabilities)
2. Space: climate, geology, and edaphic properties are grouped together based on how they respond to change
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
LRR J-SOUTHWESTERN PRAIRIES84A – Cross Timbers (Kansas, Oklahoma, and T exas)84B – West Cross Timbers (Oklahoma and Texas)84C – East Cross Timbers (Texas)85 – Grand Prairie (Oklahoma and Texas)86 – Texas Blackland Prairie (Texas)87 – Texas Claypan Area (Texas)
MLRAs
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
Ecological Site Concept• An Ecological Site is based on a core concept with a
defined amount of variability (in the climatic, geologic and edaphic properties). Variability in the temporal dynamics of the vegetation is not considered.
• An Ecological Site Description describes the distinguishing geophysical properties of a site in one section and its temporal dynamics in another section.
Describing Temporal ChangeSoil/Vegetation Concepts
• Existing vegetation can not be a primary ecological site criterion because it is easily manipulated therefore highly variable.
• The ecological site concept should be developed, using geophysical attributes that enable identification of the ecological site without vegetation on the site.
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
Information can be aggregated (Inventory)
SpatioTemporal pattern detection (Prediction and Intervention)
Predicted responses to climatic, socioeconomic factors (Modeling)
Impacts of policy and program decisions (Assessment)
Narratives for states and communities contain indicator values and managementstrategies to promote resilience. Knowledge of the amounts and spatial distribution of these requirements can inform policies and programs
Reference stateBlack grama-creosotebush savanna (historical + extant)
Indicators/DiagnosisBouteloua eriopoda >15% foliar cover, Larrea tridentata <12% foliar cover, little erosion
Ecological FeedbacksPerennial grass continuity promotes soil and water retention and fire
ManagementSummer grazing rest in drought, fire every 20 years
Reference community phaseBouteloua eriopoda (15-60% foliar cover), Larrea tridentata (1-5% foliar cover)
At-risk community phaseBouteloua eriopoda (3-5% foliar cover), large bare patches
Alternative statesShrub-dominated, shrubland states
1.3 At-riskcommunity
1.2 AnotherCommunity
2.1 Community
1.1A
1.Savanna state
2. Shrub-dominated state 3. Shrubland state
1.1 Referencecommunity
3.1 Community
T1A
T2A
R1A
2.2 Community
1.2A
1.2B1.3A
2.1A 2.2A
To date the application of Ecological Site concepts has been limited to rangeland ecosystem dynamicsLoamy SD-2
As Ecological State changes, the values and ecosystem services associated with the site change
BurrograssTarbush/Creosotebush
Mesquite/creosotebushTobosa/burrograss
Tarbush or mesquiteTobosa/burrograss
ThreeawnBlack grama
TobosaBlack grama
Black grama-tobosa grassland
TobosaBurrograss
BurrograssThreeawn
Burrograss-tobosa-threeawn grassland
Shrub-invaded grassland
Shrub-dominated
Black gramaTobosa
1a
2a
3a
4
TobosaDropseeds
BurrograssTobosa
Threeawn(Yucca)
ThreeawnMesquite
TobosaTarbush
Mesquite/YuccaThreeawn
2b
3b
5
1b
Tobosa/Black gramaMesquite
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, pollinationH
ISTO
RICA
L AN
D C
URR
ENT
MAN
AGEM
ENT
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
The status of ecological sites• In May 2010 agreement by NRCS, Forest Service, and Bureau of Land Management to
adopt ecological sites as a common framework
• Interagency ecological site working group is being formed
• November 2010 Interagency Workshop-Pilot projects for developing ecological sites following interagency requirements being considered for certain MLRAs (regions).
• August 2011 Interagency Field Workshop Cheyenne WY
• November 2011 Interagency Field Workshop Venus FL
• 2012-Reno NV, Cheyenne WY
• New Soil Ecology division within NRCS National Soil Survey Center and new staff in regional offices: 53 new full-time positions dedicated to ESDs, including cropland