Restoration of degraded land: UNU-LRT program 2018

6 – The Restoration “Toolbox” Ása L. Aradóttir

Contents
 Why do we need site specific approaches?
 Why do we focus on plants in restoration
 Plant propagation methods
 Soil/site amendments
 Things to keep in mind when selecting restoration interventions

 Recommended reading:
 Whisenant, Chapters 5-7
 Galatowitsch, S. Ecological Restoration. Sinauer Associates, Chapter 8 (and ch. 7).

6 –The Restoration “Toolbox”

 Other:
Potential approaches and methods of restoration
 Baindridge, D.A. 2007. A guide for desert and dryland restoration. New hope for arid land.
Island Press and Soicety for Ecological Restoriation International.
UNU-LRT program, 9 April 2018 Esp. Chapters 8-12.
Ása L. Aradóttir, Agricultural University of Iceland  Galatowitsch, S. Ecological Restoration. Sinauer Associates, Chapters 9-10 (invertebrates
and vertebrates)

 Which problems Restoration goals From an ecological point of view, restoration

do we expect the Provide ecosystem services (provision of food, fiber, grazing,
restoration to recreation, aestitic value , etc.); restore/protect biodiversity at all actions
levels; mitigate habitat loss; ensure resilience
solve?

 mimic natural recovery processes that can no longer

Ecological processes that form the basis for ecological restoration and happen without assistance,
 What processes do ecosystem services
we need to restore
Water Pollination  or modify conditions so that these processes can again
/ influence to solve infiltration Species
these problems Nutrient Ecological
succession
interactions create self-regenerating populations and ecosystems
cycling Dispersal
Primary
production

 What can we do to Restoration toolbox

influence these • Revegetation • Removal of invasive species
processes? • Planting trees • Restore former water table
• Mulching and • Channel reconstruction
fertilizing Galatowitsch 2012

Effective restoration planning and implementation should be

based on:
Need site-specific approaches
 Good knowledge of potential restoration methods and their applications
 Site preparation
Conditions and restoration objectives vary
 Use of fertilizers and mulches
 Methods of seeding and planting
• Which species, seeding rates/planting densities, where and when to seed/plant,
etc., etc.  “Recipies” are undesirable

 Knowledge of the organisms (species) used

 Life history and ecology
 Multiplication, propagation, strategies for use (seeding, planting or natural
regeneration)
 How to obtain the appropriate plant material
• Seed production, seed treatment, seed quality
• Seedling/plant production (nursery), cuttings
• Production and use of symbionts

 Constantly need to develop new methods/approaches to fulfill new objectives and/or

improve success
Restoration of degraded land: UNU-LRT program 2018
6 – The Restoration “Toolbox” Ása L. Aradóttir

Why emphasis on vegetation? When are interventions needed?

 Theprimary producers are necessary for “autogenic” When the ecosystems have crossed recovery thresholds:
succession and restoration of ecosystem function  natural succession is slow, e.g., due to
 Restoration of appropriate plant communities is  limited seed rain
 unfavorable conditions for plant establishment
generally the main thread in ecological restoration
(habitats for organisms, bases of ecological function)  the physical environment has been changed
 unstable soil surface
 changes in water levels
 Key species are missing or in low supply

 Increase diversity

When can we rely on spontaneous

succession and when is technical
reclamation needed? Possible interventions
 Seeding and/or planting
 Remove/ reduce effect of stressors
 Improved grazing management or protection from grazing
 Reduce erosion / eolian deposition
 Remove/control invasive species
 Soil/site amendments
 Fertilization
 Organic mulch
 Imprinting/harrowing etc., to increase surface roughness
 Restore former water table
K. Prach & R. J. Hobbs 2008. Spontaneous succession
versus technical reclamation in the restoration of
disturbed sites. Restoration Ecology 16. 363-366.

Invasive species control Mulching

Kristín Svavarsdóttir will
give lectures on invasive  Objectives
species on Tue
 Stabilize the soil surface
 Improve hydrology
 Trap seeds and nutrients
 Some types have the additional
advantage of providing organic matter,
nutrients and even seed
 Organic mulch
 ___________
 ___________
Kettenring & Adams (2011).
Lessons learned from invasive  ___________
plant control experiments: a
systematic review and meta-  Gravel and rocks
analysis. Journal of Applied
Ecology, 48, 970-979.
doi:10.1111/j.1365-
2664.2011.01979.x
Restoration of degraded land: UNU-LRT program 2018
6 – The Restoration “Toolbox” Ása L. Aradóttir

With mulch

Without mulch

Galatowitsch 2012

Selection of plant materials for seeding and

planting should be based on:

 Well defined restoration objectives

 Identification of suitable plant materials to the existing and
anticipated
 Climatic conditions (including unusual events) and microclimate
 Successional stage / degradation stage
 Soil status (moisture, pH, nutrients, erosional forces
 Disturbance regime

Other considerations in selecting species and Other considerations in selecting species and
species mixtures for restoration work species mixtures for restoration work, cont.

 Meet management objectives for goods and services  Their effects on

 Stabilize site and repair damaged processes  Subsequent arrivals (facilitation or inhibition)
 Provide appropriate genetic and functional diversity  Ecosystem function
 Be compatible with adjacent landscape components and  Their role in the desired state
other species  Tolerance of potential disturbances and harsh conditions
 Improve site conditions and initiate and encourage  Possibility to propagate the species in some quantity
autogenic repair processes without too much cost
 Potential natural regeneration
 Use native species wherever possible
Restoration of degraded land: UNU-LRT program 2018
6 – The Restoration “Toolbox” Ása L. Aradóttir

Strategies for selecting species for slope stabilization

and erosion control
(see Table 5.5 in Whisenant)
Nurse- / cover species
Function Desired qualities  Improve the growing conditions for
colonization of desirable species
Soil strength Max. root development to the  Reduce erosion and improve microclimate
required depth
 Contribute organic material to the soil
Protecting surface from wind Vigorous root and shoot
and water erosion development at soil surface; rapid  Often annuals or short lived species (should
establishment; disappear within few years)
uniform cover density
Reinforcing banks and channels Ability to grow in wet conditions and  Nitrogen-fixers (???)
variable water levels;  should not be too strong competitors
rapid effectiveness; root
reinforcement; top growth is
resistant to flow and slows it down
Provide shelter or screening Top growth of suitable height and
density; rapid development
Whisenant 1999

Strategies for selecting species for nutrient poor

conditions
(see Table 5.4 in Whisenant)

Site conditions Strategy alternatives

Low soil nitrogen Nitrogen-fixing associations;

Slow growing species that do not require high
nutrient levels
Phosphate- or water limited Mychorrizal associations – or – extensive and
environments finely branced root architecture  uptake
from large soil volume
Severe nutrient limitations Slow-growing evergreen woody species
(low nutrient demand, long tissue life, slow
decomposition  conservation of nutrients)
Productive environments Rapid growing herbaceous or woody species
 rapid resource capture to support fast
growth in competitive environment
Padilla, F.M. & Pugnaire, F.I. (2006) The role of nurse plants in the restoration of degraded
environments. Frontiers in Ecology and the Environment, 4, 196-202. Whisenant 1999

Not all species are equally important

in succession and for ecosystem function/services Why is it desirable to use local plant materials?
Drivers Passengers
 Conservation and maintenance of local biodiversity
 Have proven long-term climatic adaptations and coexistence with
other native spp.
 Visual appeal
 If species that are used for revegetation are not included in the long-
term goals for species composition of the restored area or
neighbouring areas, costly and labour intensive interventions may be
needed later on to get rid of them

Do not need to plant/seed species that will colonize unaided

Restoration of degraded land: UNU-LRT program 2018
6 – The Restoration “Toolbox” Ása L. Aradóttir

Definitions Possible role of non native (non local) species in

restoration?
 Native, natural, indegenous
A species within its natural range, that has developed within the area or has
 Where seeding/planting of non native species is in agreement with long-
term land use goals of the restored area
dispersed though natural pathways
 It may be possible to use non native species to produce plant cover and
 Alien, introduced, exotic, foreign biomass early in succession IF
A species outside its natural range, which has been introduced by man
 They do not deter the colonization of native species
(regardless of when the introduction took place)
 There is good certainty that they will disappear with time
 Invasive  They are unlikely to have negative effects on native species or habitats
An introduced species that shows (a) great or rapid expansion or (b) is likely
to damage local biodiversity or cause environmental or economical damage

Invasive species will be covered in lecture by Kristín Svavarsdóttir

Based on: Menja von Schmalensee 2010. Vágestir í vistkerfum – fyrri hluti. Stiklað á stóru um
framandi ágengar tegundir. Náttúrufræðingurinn 80: 15-26.

Problems with using non native plant species Use of native species for revegetation
 Some can colonize and spread outside of their natural habitat  negative effects  Worldwide there is growing emphasis on the use of native species and local plant
on other species, communities and ecosystems material in restoration, and lesser emphasis on use of genotypes that are the result
 Invasive alien species are among the most important direct drivers of biodiversity of intensive breeding and/or selection
loss and ecosystem service changes
 Costs due to invasive alien species can be very high:  A number of countries now have regulations that non native species cannot be
 eradication – management (hundreds of billions of US $, just in the USA) used in restoration work
 + costs due to other damage by alien spp. on ecosystems, in agriculture and other
cultivation.  CBD – biodiversity convention:
 Many of the species that are now causing problems were originally imported for  Article 8. In-situ Conservation
use in agriculture, restoration and horticulture
• (f) Rehabilitate and restore degraded ecosystems and promote the recovery of
 Not all exotics are invasie, but… threatened species, inter alia, through the development and implementation
of plans or other management strategies;
 Paradox: Desirable properties of species for restoration purposes are the same • (h) Prevent the introduction of, control or eradicate those alien species which
that characterize invasive species  relatively high risk of non-native species threaten ecosystems, habitats or species;
used for restoraiton becoming invasive
 It is important to think about the long-term consequences of our actions today as  In many countries restoration objectives are changing
their effects may be seen for decades or centuries!
 ↑ emphasis on restoration of native ecosystems
 have to be careful to include considerations of biodiversity when restoring for other
purposes, e.g. carbon sequestration
Pimentel et al. 2000. Environmental and economic costs of nonindigenous species in the United States. BioScience 50:53-65.

Use of plant materials that have been selected by

Seed / seeding
breeding?
Whisenant makes a case that our basic paradigms for breeding and Seed is
selecting plant materials are flawed when applied to wildlands.
 Easy to handle
Why?
 Relatively inexpensive to transport
Plant materials in semiarid and arid ecosystems are often selected for  No need for labor intensive/expensive growing nursery
forage quality and productivity, which are often determined in irrigated
nurseries -> favors genotypes that may be wrong for water and nutrient Seeding
limited environments  Direct seeding is a relatively inexpensive method to
Limited options for use in harsh environments establish many individuals
 Where germination is limited & mortality of seedlings is
Should, however, consider the practicality of using cheap and readily
available commercial seed mixtures for specific purposes high -> not very good use of seed
 Results depend very much on site conditions
Restoration of degraded land: UNU-LRT program 2018
6 – The Restoration “Toolbox” Ása L. Aradóttir

Seed collection Seed production of wild species

 With large machinery
(esp. grasses)
 Axes at similar height
 Seed developed at similar time
 Selection during seed production
 With smaller machines
 By hand

Native Seed Industry

http://www.nativeseednetwork.org/index

The establishment of seed

production may take several
years

Steinfeld, D.E., S.A. Riley, K.M. Wilkinson, T.D. Landis & L.E Riley 2007. Roadside
Revegetation: An Integrated Approach To Establishing Native Plants. Report nr. FHWA-
WFL/TD-07-005. Federal Highway Administration, Vancouver, 424 bls.
http://www.wfl.fha.dot.gov/td/revegetation.htm

Things to keep in mind when deciding which

plant materials to collect

 Genetics are important for the success of restoration projects – especially in

the long run
 Practitioners should be aware of the degree of genetic diversity with which
they are working
 How the plant material was generated, how was it obtained and/or propagated
(ask the collector, propagator what steps were taken to assure suitable range of
genotypes)

Espeland et al. 2017. Evolution of plant materials for ecological restoration: insights from the applied and basic
literature. Journal of Applied Ecology 54(1), 102-115. 10.1111/1365-2664.12739

35
Restoration of degraded land: UNU-LRT program 2018
6 – The Restoration “Toolbox” Ása L. Aradóttir

Things to keep in mind when deciding which Other methods to obtain seed/ propagules
plant materials to collect  Seed containing hay
 Genetics are important for the success of restoration projects – especially in the long  Use old hay from hayfields
run
 Transfer of fresh hay:
 Practitioners should be aware of the degree of genetic diversity with which they are Cutting of wild areas  distribute over areas to
working
be reclaimed
 How the plant material was generated, how was it obtained and/or propagated
(ask the collector, propagator what steps were taken to assure suitable range of genotypes)
 Ordinary fodder hay not especially
 Different species have different life histories and different degree of gene flow
 various approaches in selecting plant material appropriate
 Is historical accuracy or ecosystem function the main driver of the restoration?  Freshly cut vegetation can be used as
 Collection from local populations may be beneficial, but is not always the best way
to obtain adapted materials source of seed for some native species
 Large and genetically variable populations may be a better source than small  Cutting at a time of seed maturity of
populations with limited diversity desirable spp.
 Combination of materials from several suitable sites may be desirable in order to
capture a wider array of genotypes that can succeed in the new location  Density of seeds may be low
 Genotypes introduced from other locations can swamp out local populations if the  Danger of valuable seed being lost in
former are used in large amounts. If the objective is to enhance local populations, handling
one has to be careful not to use too much introduced material
 Hay doubles as organic mulch
Photo: Járngerður Grétarsdóttir

37

Storage and use of topsoil

Other methods to optain propagules mines, road construction, etc.
 Topsoil (storage or moving of...)
contains Edge of
 Fertile soil – plant nutrients and soil mined area
Edge of subsoil
biota mined area topsoil
topsoil
 Seed and plant parts, especially top
cm
• Seed bank in soil
• Species composition often different than
the local vegetation
• Weed seed can cause problems

Subsequently the subsoil is stockpiled

Before mining the topsoil is stockpiled
separately

Example from strip mining

Storage and use of topsoil
mines, road construction, etc.

subsoil
topsoil topsoil

A: Mining and reclamation completed

B: Mining completed
After mining is completed the surface of the
area is graded and Finally the topsoil is spread over the area, C: Topsoil is being salvaged for spreading over area B
subsoil spread over it, forming at least a 20 which is now ready for revegetation
D: Original plant cover (ecosystem or production system
cm thick layer

Úr: Námur. Efnistaka og frágangur. Náttúruvernd ríkisins o.fl. 2002

Restoration of degraded land: UNU-LRT program 2018
6 – The Restoration “Toolbox” Ása L. Aradóttir

Direct seeding Seeding rate

 Too high
 Preparation of seed (not always necessary)  costly
 mortality due to ‘self-thinning’
 Break dormancy
 Danger of outcompeting other spp.
 Inoculation with symbionts
 Too low
 Time of seeding, depends on  not enough cover
weeds can flourish
 Accessibility for machinery (where used)
 Climatic factors  Seed quality can vary
 Danger of predation / erosion  germinability
 Growth pattern / phenology of seed maturity  purity (other species, incl. weeds)

 Price of seed also plays a role

 Expect mortality, especially under harsh conditions

Planting What is planted

 May be used under harsh conditions  Transplantation of wild plants (trees, shrubs)
 Reduces uncertainty due to germination and colonization  Plants grown in nursery
 Quicker establishment process than from direct seeding  Bare rooted plant stock
 May be the only potential approach  Containerized plants
 For species that primarily regenerate vegetatively  Sward transplants
 Where germination is limited or none (poor seed, difficult
conditions)  Various plant parts
 Seed is limiting due to  Sprouts /sprigging (grasses, forbs)
• Cost  Stem and/or root cuttings (e.g. willows, poplar)
• Limited availability of seed

Planting of seedlings grown in nursery Plants from nursery

 Various methods
 See Bainbridge 2007 for practical considerations and
specialized approaches for very dry areas

Baindridge, D.A. 2007. A guide for desert and dryland restoraiton. New hope for arid land. Island
Press and Soicety for Ecological Restoriation International. Esp. Chapters 8-12. Mynd úr D.E. Steinfeld, S.A. et. al. 2007.
Restoration of degraded land: UNU-LRT program 2018
6 – The Restoration “Toolbox” Ása L. Aradóttir

Root development wanted

Restoration v/s landscape plants
 Small shoots and vigorous roots
are wanted
 The root/shoot ratio should
favor roots
 Fertilizer management and
pruning may be used to get
good root/shoot ratios

Baindridge, D.A. 2007. A guide for desert and dryland restoraiton. New hope for arid land. Island Baindridge, D.A. 2007. A guide for desert and dryland restoraiton. New hope for arid land. Island
Press and Soicety for Ecological Restoriation International. Esp. Chapters 8-12. Press and Soicety for Ecological Restoriation International. Esp. Chapters 8-12.

Turf transplants Turf transplants

 Utilizes vegetation that would otherwise be destroyed Different approaches:
(e.g., with construction of roads, dams, etc.)
 Recreate original arrangement of turfs (same area)
 Distribute turfs over a larger area (1:25, 1:50, 1:100 or 1:200 dilution)
 Advantages:
 sources of propagules for further colonization
 If successful, the transplants can form functional plant communities in a short
time
 Source of important diversity, seed bank, microbes and other organisms; also
mosses, lichens and other species not normally included in restoration projects 2007 2008

 Problems
 May require machinery. Have to be able to take thick enough sward to transfer
fairly intact root systems
 High labor / cost per unit area
 If environmental conditions of the receiving area are very different from the giving
area, there is a chance of failure.
 Can not be used as an excuse to destroy undisturbed vegetation communities
Myndir: OR

Different species have different tolerance to Planting of

division into small turfs
Turf fransfer
cuttings
Large Photos: Ása L. Aradóttir
 Optimum turf size
 Can use parts of above- or belowground
 Evergreen dwarf shrubs stems (stolons & rhizomes)
Whole turfs

 Deciduous dwarf shrubs  stem cuttings

 or individual sprouts
 Sedges and many species of forbs
 Grasses (small turfs, 5x5 cm)
Small
 Mosses (highest cover in plots with shredded
turfs)
Tættar torfur

Karlsdóttir, L. Og Á.L. Aradóttir. 2006. Propagation

Aradottir, A. L. (2012). Turf transplants for restoration of alpine vegetation: of Dryas octopetala L. and Alchemilla alpina L. by
does size matter? Journal of Applied Ecology 49, 439-446. direct seeding and planting of stem cuttings. Icel.
Photos: Lilja Karlsdóttir 2002 Agric. Sci. 19, 25-32.
Restoration of degraded land: UNU-LRT program 2018
6 – The Restoration “Toolbox” Ása L. Aradóttir

Specific problems: halting of moving sand and

rapid erosion Seeding of sand binding vegetation

 Sand fences
 Revegetation of and around
erosion escarpments
(rofabard)
 Revegetation
 Establish vegetation that binds
the sand and soil

Sand fences Revegetating erosion escarpments

Restoration of degraded land: UNU-LRT program 2018
6 – The Restoration “Toolbox” Ása L. Aradóttir

Revegetating erosion escarpments (Rofabard)

 Use organic mulching (e.g. Hay or manure)

 Revegetation with fertilizer and seeding
 Revegetate surrounding areas, and thus reduce the power
of erosive forces
 Fertilization and/or protection of grazing in order to
reinforce the natural vegetation

Unassisted natural recovery (spontaneous

succession) Utilize natural regeneration to your advantage
 Advantages
 Inexpensive  Possible to reduce costs, e.g., by encouraging natural seed
 Leads to formation of ecosystems that are adapted to local conditions production and dispersal
 Disadvantages  Establish seed sources
• ↓ dispersal distance
 Often very slow
• Number vs. size (edge effects)
 We have little control over species composition and structure
• ↑ probability of using recruitment opportunities
• Too little seed rain of desirable spp.
 Facilitate animal dispersal
• Too much seed rain of undesirable spp. (weeds)
 Facilitate increased wind dispersal
• Disproportionate abundance of easily dispersed species (wind or animal
dispersed) • Height of vegetation / location in the landscape
• Very much influenced by nearby flora/plant communities • Design with regard to dominant wind direction (dry) during the
main dispersal period
 Success depends on the degree on disturbance and
resilience of the ecosystem in question

Often an inverse relationship between cost and time

Planting, seeding or natural regeneration? 2
5 4 3 1
 Direct seeding may be a good approach if:
 sufficient amount of relatively inexpensive seed
available Great Cost Small
 conditions at the area are conductive for seed
germination, seedling establishment and growth Intensive restoration Limited restoration Unassisted
 Planting may be a better choice if: treatments over the whole interventions to natural recovery
 seed of desirable spp. is expensive or not area stimulate recovery
available
 unfavorable conditions for seedling establishment
Short Time
 However planting is more expensive and labor Long
intensive than direct seeding, and is therefore
rather used for smaller areas  Seeding or planting of desirable species into the whole area under question can
 Encourage natural regeneration result in rapid recovery of structure (and some function) but is expensive
 Other methods  Unassisted natural recovery is often slow but requires very little intervention.
 Often some happy medium is the best approach

Aradottir & Hagen 2013

Restoration of degraded land: UNU-LRT program 2018
6 – The Restoration “Toolbox” Ása L. Aradóttir

Comparison of recovery strategies Not either spontaneous Limited interventions

See also table 6.1 in Whisenant succession or technical
Strategy Description Advantages Disadvantages
reclamation
1. Unassisted natural No seedbed modification Low establishment Slow, depending on seed crops
recovery Reliance on natural seed dispersal costs Little control
mechanisms Little soil disturbance Competing veg. may reduce
success
 Interventions aimed at
2. Restoration Selective seedbed modification Moderate May be slow when seedcrops are
overcoming barriers or
treatments to increase Relies on natural seed dispersal establishment costs low thresholds to spontaneous
seedling establishment Not dependent on May require soil disturbance
(improve availability of
May need to control competition
availability of
succession
More expensive than unassisted
safe sites) commercial plant natural recovery
material  Nature does the rest
Limited control

3. Restoration Establish seed sources Low to moderate costs Limited control

treatments to increase Increase seed production of Little disturbance Slow if poor seedbed
seed rain existing seed sources (fert. or Competing vegetation may reduce
protection from grazing) success
4. Artificially induced (2+3) Selective seedbed Some control over High establishment costs
recovery modification species change Poorly chosen species mixtures
Artificial addition of selected plant may not achieve objectives
material to form seed sources K. Prach & R. J. Hobbs 2008. Spontaneous
succession versus technical reclamation in the
5. Technical Whatever it takes High control High establishment costs restoration of disturbed sites. Restoration
reclamation, including Less time until desired High labor and equipment Ecology 16. 363-366.
“wholesale” planting species composition requirements
and seeding of Danger of insect and disease
desirable species problems

Selecting appropriate methods:

 Many possible methods:  Factors affecting choice of methods:
 seeding  cost
 planting of seedlings  time frame
 planting of cuttings  availability of plant material
 movement of topsoil  available work force
 transplantation of sod/turf  conditions of the area under
 stimulate natural regeneration restoration, including stablility of the
soil surface
 etc.
 DEPENDS ON PROJECT OBJECTIVES, SITE
CONDITIONS, AVAILABILITY OF MATERIAL
AND OTHER CONTEXT