ECOLOGICAL SITES EXPANDING the CONCEPTS and APPLICATIONS of ECOLOGICAL SITES Joel Brown USDA NRCS Jornada Experimental Range Las Cruces NM.

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