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Nurse plant theory and its application in ecological restoration in lower subtropics of China

  • South China Botanical Garden
  • Guangzhou Institute of Geography

Abstract and Figures

Nurse plants are those that facilitate the growth and development of other plant species (target species) beneath their canopy because they offer benign microhabitats that are more favorable for seed germination and/or seedling recruitment than their surrounding envi-ronment. Nurse plants have been mainly used to restore vegetation in arid and sub-arid zones in recent years. Based on summarizing the definition of nurse plant and target plant, we review the nursing effect mechanisms, ecological factors that influence nursing effect, rela-tionships between nurse plant and ecological restoration. This review also brings forward possible pairs of nurse and target species at lower subtropical areas. Furthermore, we provide the potential tendency in nurse plant research and application.
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Nurse plant theory and its application in ecological restoration
in lower subtropics of China
Hai Ren
, Long Yang, Nan Liu
Heshan National Field Research Station of Forest Ecosystem, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
Received 28 May 2007; received in revised form 13 July 2007; accepted 13 July 2007
Nurse plants are those that facilitate the growth and development of other plant species (target species) beneath their canopy because
they offer benign microhabitats that are more favorable for seed germination and/or seedling recruitment than their surrounding envi-
ronment. Nurse plants have been mainly used to restore vegetation in arid and sub-arid zones in recent years. Based on summarizing the
definition of nurse plant and target plant, we review the nursing effect mechanisms, ecological factors that influence nursing effect, rela-
tionships between nurse plant and ecological restoration. This review also brings forward possible pairs of nurse and target species at
lower subtropical areas. Furthermore, we provide the potential tendency in nurse plant research and application.
Ó2007 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in
China Press. All rights reserved.
Keywords: Nurse plant; Target species; Forest restoration; Nursing effect
1. Introduction
The relationship between plants, mainly including com-
petition (negative effect), neutral, and facilitation (positive
effect), is an important driving force of plant community
succession or vegetation restoration. Ecological research
has been focused on competition. Research on positive
interaction between plants is still ignored [1] although it
is gradually known as competition and facilitation (at
least one side benefit) in the plant communities of the
main biome of the world in the past 15 years. Nurse
plants are those which facilitate the growth and develop-
ment of other plant species (target species) beneath their
canopy because they offer benign microhabitats that are
more favorable for seed germination and/or seedling
recruitment than their surrounding environment, for
adjusting light, temperature, soil humidity and nutrient,
as well as avoiding grazing [2,3]. Nurse plants can also
establish the seedlings of target species through positive
interaction between plants. Nursing effect is mainly
accomplished by the interactions between plants, which
influence community structure and dynamic performance
intensively and the appearance or absence of specific spe-
cies [2,3]. So the research on nurse plant can validate,
consummate and enrich the theory that interactions
among plant species drive the natural succession, which
also provides the meaning of ecological restoration. In
this paper we review the application of nurse plant in res-
toration ecology and the future development of this
research field and especially discuss the possible pairs of
nurse and target species at lower subtropical areas and
its applications in forest restoration.
2. Nurse plant and target species
2.1. Nurse plant
Nurse plant plays an important role in recovering the
structures and functions of primary ecosystem and is
1002-0071/$ - see front matter Ó2007 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited
and Science in China Press. All rights reserved.
Corresponding author. Tel.: +86 20 37252916; fax: +86 20 37252831.
E-mail address: (H. Ren).
Available online at
Progress in Natural Science 18 (2008) 137–142
thought to be a driving force in the succession of certain
environments, especially in extremely degraded ones. In
recent years, the phenomenon of nurse plant has been
investigated in degraded habitats, including Mediterranean
mountain, alpine habitat, arid desert, semi-arid shrub-land,
northern dry forest, savanna, ecotone between farmland
and pasture, swamp, tropical sub-humid forest, marshes,
and so on [2,4–9].
The selection of nurse plants determines the success of
the ecological restoration project. Some nurse plant and
target species pairs have been confirmed in the study of
the world’s main biomes in the past few years. In the
extremely degraded environment, the best nurse plants
are the native species that offer microhabitat for target
plant establishment or recruitment. Although some exotic
species (e.g. Robinia pseudoacacia in southern England)
are successfully used as nurse plant, the biological invasion
of those species should also be prevented. Unpalatable
species can be used in heavily grazed sites, because these
nurse plants can provide refuges for small animals and tar-
get species [2,10,11]. It has been found that acervate plants
evidently facilitate target plant seedling survival in rainless
years. Legumes species are potential nurse plants which can
improve the survival and growth of target species in desert
and Mediterranean semi-arid habitat for their amelioration
in soil nitrogen and overshadow function. However, the
effect is undesirable when both nurse and target plants
are legumes [12]. In desert, shrubs usually act as nurse
plants for other seedlings, especially cacti. In forest, seed-
ling establishment may be enhanced in the vicinity of adult
plants that improve some extreme ecological factors [7].
This kind of positive effect by adult plants on their sur-
rounding seedlings is called Nurse Plant Syndrome. The
selection of nurse plants should avoid those species that
release allelopathic compound. It is reported by Sanchez-
Velasquez et al. [10] that different shaded levels formed
by the nurse plant in the tropical sub-humid forest are
significantly related to seedling establishment of target
Field survey is the foundation of nurse plant research.
Generally, the species richness under nurse plant is higher
than that in the open sites. Therefore, the nursing
relationship between plants can be approximately esti-
mated by interspecific association. Furthermore, the influ-
ence of nurse plant on seed germination of target species
is examined by sowing seeds under nurse plant [13].
Seedling inseminations are mostly introduced in the
confirmation of nurse plant and nursing effect between
plants. In these experiments, the differences of seedlings
of target species under the nurse plant and on the open
(or between two crowns) are usually compared by analyz-
ing survival rate and growth rate between them, combin-
ing observation of microhabitat. However, it should be
indicated that the differences of soil physiochemical prop-
erties and microhabitat between under nurse plant and in
the open are not obvious in some cases of facilitation
2.2. Target species
The effect between plants is dependent on characteristics
of each species, which means the selection of target species
(regenerated ones) would also influence the restoration
effect. Furthermore, the balance of the interaction is
decided by the ecological requirement of target species
and capability of dealing with incompatible habitat [16].
The positive effects of nurse plant on the shaded-tolerant
pine and shrubs in late succession period are more than
those on pioneer species and shaded-intolerant species
[12]. The survival rate of Ambrosia dumosa in the open of
arid environment is higher than that under shrubs because
of its better adaptation in the open habitat, wherein, the
interaction between A. dumosa and the nurse plant is com-
petition, so that this species is not suitable as a target spe-
cies. If the tolerance of target species is poor in abiotic
habitat or the environment is extremely serious (such as
dry year), nurse plant cannot increase the seedling estab-
lishment [17].
The age and size of target species should also be consid-
ered for the balance of facilitation and competition accord-
ing to different life periods. The nurse plant has a stronger
positive effect when the target species is young, whereas,
competitive interaction is dominant when there are older
or bigger target plants. When the age and size of the nurse
plant is similar to that of the target species, the negative
effect of tussock plants will be enhanced [18].
2.3. Positive and negative nursing effect
Only when the intraspecific competition exceeds inter-
specific competition, can plant species coexist in a commu-
nity. Most interactions among species are represented
through some intermediary, for example, light, nutrition,
pollinator, herbivore and microbe. Competition actualizes
by competing resources directly, but facilitation is realized
by intermediary (such as soil) among species interaction
Higher recruitment success near the nurse plant cannot
eliminate the negative effect on target species, but it is
sure that positive effects exceed negative ones, which
result in the higher survival rate of target species under
the nurse plant than that in the open [21,22]. When arti-
ficial methods such as shading or watering are used, the
survival rate of target species may be lower than that
under the nurse plants. For example, Neobuxbaumia tet-
etzo, a cactus in Mexico, is nursed by Mimosa luisana,a
leguminous shrub, but the former species restricted the
growth of the nurse plant and consequentially substituted
it. Further research indicated that the survival rate under
the nurse plant was higher than that on the artificial mea-
sures such as shading. In addition, it is shown by the
experiment on Savanna in south Texas that nurse plants
grew better by clearing the target species under the nurse
plants, which can be described as the interaction of the
parasite/host [23,24].
138 H. Ren et al. / Progress in Natural Science 18 (2008) 137–142
Plants, when growing closely, compete directly for lim-
ited resources (such as light, water, nutrition and space)
if negative effect predominates. However, if positive effect
predominates, the neighboring plants will show this inter-
action by increasing survival, growth and fitness. Both
effects would take place simultaneously and change accord-
ing to time and places, which are balanced by expression of
the positive and negative ones. Some factors (such as phys-
iological and developmental characteristics) may influence
the balance [18], wherein the abiotic factors are mostly
important for increasing the importance of positive effect
in stressful habitats [4].
3. Reasons and mechanism of nursing effect
The nursing effect may not be attributed to single factor,
but to the ultimate performance of some compound fac-
tors, including the crown architecture effect (influencing
extinction coefficient, photosynthetic availability radiation,
and temperature buffering), shading increment, buffering
extreme temperature in microhabitat, increasing water,
nutrition availability (litter of nurse plants), protection
against herbivores, impact epiphyte and azotobacter in
soil, and so on. However, among the above environmental
factors, key factors should be explored in finding out the
reasons of nursing effect [2,25].
Nurse plants facilitate target species by shading from
crown architecture. Dewpoint temperature in winter under
nurse plant Cercidium microphyllum was higher than that in
the open of Sonoran Desert. Shading can protect plants
under the nurse plant from strong radiation. Kulheim
et al. [26] reported that light influences plant physiological
process directly and indirectly, and interspecific differences
are found in response to illumination in forest plants.
Strong irradiation may destroy reaction centers of photo-
systems and produce oxidative damages. Shade-tolerant
species under abundant sunlight will suffer from photoinhi-
bition. Shading can avoid higher temperature, maintain
higher soil humidity and lower transpiration of target spe-
cies, moreover, it increases rhizosperic nutritious availabil-
ity and circulation. All the processes above will improve
physical and chemical property of soil and increase survival
rate of target species [2,27,28].
Establishment of target species is affected by rainfall
redistribution of nurse plant canopy. Shrubs constrain
available understory water by rainfall redistribution at a
lower intensity of rainfall, whereas, when there is a heavy
rainfall, its redistribution by shrub crown arrives at under-
story through stem flow, which will influence the develop-
ment of target species [29]. The distance between target
species and nurse plant is another important factor and
the stressful condition is ameliorated gradually from the
center to the edge of canopy [30]. Castro et al. [29] planted
two pine species (Pinus sylvestris and Pinus nigra) in the
open, under the crown of sage (Salvia lavandulifolia) and
beneath the crown of thorny shrubs (north and south direc-
tions), thus finding out that the survival rate was much
higher under the north aspect of thorny shrubs. Nurse
plants influence mainly target species on germination and
seedling stage, wherein, positive effect may be showed evi-
dently on seedling stage. It is believed that, nurse plant of
predominant species in one successional stage will facilitate
plants in the next successional stage by allelopathy.
Changes of physiological balance between shading and
drought were discussed by graph model [2]. In addition,
some factors such as competition, consumption of
resources by the nurse plant and superposition of root
space between the nurse plant and target species should
also be considered. Competition or disturbance of non-tar-
get species under the crown of the nurse plant (i.e. herba-
ceous plants) will play positive roles [1–4].
4. Ecological factors that influence positive effect
Even if positive effect takes place between nurse plant
and target species, ambient condition (such as rainfall, soil
humidity, grazing intensity and microhabitat) influences
the radiation, soil, temperature and moisture under the
crown of nurse plant, thereby changing the nursing effect.
Positive effect of nurse plant increased with stressful abiotic
conditions which was obviously stronger in higher moun-
tains and on earlier restoration stage of degraded ecosys-
tem [4].
In the overexploited area of Mediterranean Basin, 11
woody species were planted under 16 pioneer shrubs, which
could aid in the establishment of woody species on later
successional stage. The successful rate was improved in dif-
ferent habitats by using meta-analysis to analyze survival
and growth among those species [31].
In a relatively nice habitat, spatial association among
plants may be negative, but not positive. In a fertile habitat
it was not positive by using nurse plant for its exhausting of
soil resources. However, in an unfertile habitat, crops with
small crown and poor growth facilitated the survival of syc-
amore seedlings [1,2].
In dry areas, changes in precipitation may alter the
interactions among plants from competition to facilitation
and vice versa. Ibanez and Schupp [32] conducted an exper-
iment in Logan Canyon. They found that when the seed-
lings of curl-leaf mountain mahogany (Cercocarpus
ledifolius) were placed under big sagebrush, facilitation
was apparent in a dry year whereas negative effects were
obvious during a wet year.
5. Case studies of nurse plants in vegetation restoration in
lower subtropical areas of China
The nurse plant should be used in ecological restoration,
mainly because the establishment of target species is greatly
influenced by abiotic habitat and disturbance. Natural
nurse plants were firstly put into ecological restoration in
southeast Spain, where Castro et al. [29] found that native
shrubs did not restrain the growth of two pine species
but decreased their death rate. They comprehensively
H. Ren et al. / Progress in Natural Science 18 (2008) 137–142 139
considered some ecological and biological characteristics,
such as rainfall, nurse species and target species, when
applying nurse plants to improve seed germination and
seedling establishment in ecological restoration.
Through extensive field investigation, interspecific asso-
ciation studies and field experiments, possible correspond-
ing nurse and target species pairs were found in lower
subtropics in China (Table 1).
Tussock plant Evolvulus alsinoides L. with 20 cm root
system and only 3 cm high above ground is the unique nurse
plant grown on a bare land of extremely degraded ecosys-
tem at Xiaoliang, Guangdong Province. We found that E.
alsinoides’s target species Phyllanthus cochinchinensis can
grow with 60 cm root length and 42 cm root spread range
with 27 cm height above ground. In severely degraded eco-
system, there exist two kinds of thresholds during ecosystem
restoration, which are the initial threshold characterized by
extremely harsh physical environmental conditions (includ-
ing high temperature, aridity and poor soil) and the second-
ary threshold controlled mainly by biodiversity level and
landscape context to seed provenance and establishment.
In this circumstance, nurse plants are grass clustered with
deep root, and so are target species. The formed tussock
community is not only propitious to themselves but also
advantageous in their resistance to poor environmental
conditions. Enlightened by the above field phenomenon,
exotic leguminous species, Acacia auriculaeformis, with fast
growth rate and better resistance to infertility, was intro-
duced as nurse plants at the severely degraded bare land
of Xiaoliang. We planted several A. auriculaeformis individ-
uals clusterly, then removed 1–2 individuals of 2-year-old
plants from the fascicular A. auriculaeformis and some
native species were planted under its canopy, including Psy-
chotria rubra,Pithecellobium clypearia,Syzygium hancei,
etc., whose survival rate could reach 80%. The survival rate
is about 0% if those native plants are directly planted in bare
lands. Similar experiment was also successful when carried
out at Nan’ao island [33–35].
It was found that a pioneer grass Neyraudia montana,as
the nurse plant of pioneer shrub Rhodomyrtus tomentosa,
provided better microhabitat at grasslands of Heshan Sta-
tion and Dinghushan Station, Guangdong Province, which
were considered to be mild degraded ecosystem. Pinus mas-
soniana, for its amelioration in light environment and soil
property, was the nurse plant of Schima superba at Heshan
Station, Dinhushan Station and Nan’ao Island. Castanop-
sis chinensis can facilitate Schima superba and Cryptocarya
concinna at Dinghushan Station, probably because of the
effects on shading, moist increment and enhancing avail-
able nutrient in soil [33].
Exotic species Sonneratia apetala has nursing effect on
native mangrove plants Rhizophora stylosa and Kandelia
candel at the coastal mudflat in the tideland area of Zhanji-
ang [36]. We had found that the survival rate of planted
native mangrove species was very low at the severely
degraded mudflat, however, the survival rate of S. apetala
reached 95%. S. apetala grew fast and became a closed
artifical forest within four years which could efficiently pre-
vent the swashing of tidal wave, and increase soil nutrient
therefore facilitating the invasion of some native mangrove
species. The number of species and intensity of native spe-
cies came to a peak in the artificial forests after six years of
From these nurse plants and target species, the pattern
[36–40] is found as follows. (1) The phenomenon of nurse
plants takes place mostly on the early stages of restoration
in degraded ecosystem or succession in plant community.
(2) The phenomenon of nursing effect on the earlier stage
of restoration or succession is mostly carried out as shrubs
nursed by grasses and trees nursed by shrubs. (3) Nursing
phenomenon usually happens among the native species in
corresponding pairs. (4) Exotic leguminous species, Acacia
auriculaeformis and Acacia mangium, are considered as
good nurse plants for ameliorating N condition in soil
and providing shade for target species including shrubs
and trees. (5) Nurse plants have better characteristics than
Table 1
Possible nurse and target species pairs at south subtropical areas in China
Places Nurse plants Target species
Bare land at Xiaoliang Evolvulus
Artificial forest at Xiaoliang Acacia
Hillyland at Heshan Neyraudia
Artificial forest at Heshan Acacia
Hillyland at Dinhushan Neyraudia
Coniferous and broad-leaved mixed
forest at Dinghushan
Schima superba
Schima superba
Broad-leaved forest Castanopsis
Artificial forest at Nan’ao Island Pinus
Schima superba
Schima superba
Artificial mangrove in National
Natural Reserve of Zhanjiang
Kandelia candel
140 H. Ren et al. / Progress in Natural Science 18 (2008) 137–142
those of target species, including being light-dependent,
fast-growing, infertility resistant and drought tolerant. (6)
The individuals of target species are generally smaller than
those of nurse plants in the early stage. (7) Seedlings can
successfully establish around the adult plants in forests
for the amelioration of some extreme ecological factors.
(8) Nurse plants are considered not only to play a key role
in recovering the properties and functions of the primary
ecosystem, but also to drive succession in poor environ-
ments on the early stage of restoration.
6. Perspective in the study and application of nurse plants
Recently, most researches are focused on seedling sur-
vival of the target species, but less on the research of seed
germination, seedling growth and fitness. Most researches
rest on describing the phenomenon of the nurse effect, less
on the structural and functional mechanisms of positive
effects towards ecophysiological and morphological aspect.
With the purpose of ecological restoration, most researches
concern about the influence of nurse plants on target spe-
cies, but less on the feedbacks of target plants and without
long-term observation in their interactions. Most species
studied are native ones due to easy manipulation and pre-
diction, lacking studies in exotic species. Nurse plants are
mostly tussock shrubs, but not herbaceous or woody spe-
cies, and fewer studies combine nurse plant with target spe-
cies representing different successional stages. Nurse plants
were less investigated in degraded ecosystem, especially in
China, therefore, further tests are needed to find out the
potentials of nurse plants in reforestation.
Currently, the main forest recovery methods include
closing hillsides to facilitate afforestation (natural succes-
sion), artificial reforestation (rebuilding artificial pure for-
ests or mixed forests directly), rebuilding forest
construction (planting native species after picked logging)
and Miyawaki’s method (growing seedlings of native spe-
cies directly). All of these methods have both strong or
weak points. Some reforestation technologies, such as
nutritive cup, water retaining agent, nodules, and shading,
were developed to match the above methods [38–42].
The nurse plant technique is different from the above
reforestation methods. Due to the functions of nurse plant
in ameliorating microhabitat (such as shading and water
increment, extreme temperature buffering in microhabitat,
and so on) suitable target species were grown under the
crown of nurse plants. Even more, positive effects among
plants make target species establish successfully and short-
ened restoration course. The successful utilization of nurse
plants may become a novel reforestation method which will
explore excellent native species, accelerate natural recovery
and enrich species diversity.
This work was supported by National Natural Science
Foundation of China (Grant Nos. 30200035, 30670370),
the Chinese Academy of Sciences and the Guangdong &
Guangzhou Sci-Tech Planning Project (07118249,
2005B60301001, 2007J1-C0471). We are grateful to Dr.
Huang Changzhi in CDFG/OSPR/Scientific Division of
Sacramento in USA and Dr. Lu Hongfang in EPA of
USA for the assistance in English writing of this
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... Fire is one of the main disturbances influencing vegetation, plant biodiversity, and the functioning of terrestrial ecosystems [1][2][3][4][5][6]. For instance, fire can drive significant changes in species composition and species richness through a decrease in the competitive impacts of some woody plants [7]. ...
... Some evidence suggests that, in addition to species composition changes, functional traits such as life form, plant height, specific leaf area, and leaf carbon and nitrogen content can change with changes in fire occurrence [9]. Such changes in species composition and functional traits following the fire may or may not result in significant variation in evolutionary diversity, depending on how functional traits are conserved across phylogenies [2,10]. ...
... Vegetation restoration is one of the most important objectives of management and sustainable development of arid and semiarid shrublands [11,12]. However, restoration is highly dependent on disturbances, and on the temporal scales of imposed disturbances [2,10,13,14]. In this regard, some evidence suggests positive correlations between vegetation restoration and time intervals, such as increased time intervals generally promoting increased plant biodiversity, coverage percentage, and abundance of plant species [15]. ...
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Citation: Bashirzadeh, M.; Abedi, M.; Shefferson, R.P.; Farzam, M. Post-Fire Recovery of Plant Biodiversity Changes Depending on Time Intervals since Last Fire in Semiarid Shrublands. Fire 2023, 6, 103. Abstract: Fire is a key disturbance affecting plant biodiversity patterns and evolution. Although a wide range of studies have shown important impacts of fire on vegetation, most have focused on taxonomic diversity, with less emphasis on other aspects of biodiversity, such as functional and phylogenetic diversity. Therefore, we assessed the recovery of biodiversity facets across different times since the last fire in semiarid shrublands in Northeast Iran. We quantified changes in plant biodiversity facets, including taxonomic, functional, and phylogenetic diversity, and the diversity of seven functional traits in five ecologically comparable sites that have experienced wildfire disturbances at short-term (1 and 4 year sites) and long-term (10 and 20 year sites) intervals, in comparison to an unburnt site. Our results showed significant changes in all biodiversity facets related to the year since the last fire, with a significant increase in biodiversity and diversity of functional traits under long-term rather than short-term conditions, and in comparison to the unburned site. We conclude that wildfire influences the presence of plant species with distant functional and evolutionary relatedness and causes an increase in plant species and diversity of functional traits depending on time intervals. Therefore, wildfire can promote positive effects on the recovery of biodiversity aspects and the evolution of vegetation in semiarid shrublands.
... Shrubs, however, change vegetation characteristics under the canopy through seed capture, promote seed production and protect topsoil, which can promote the growth and development of other plants under the canopy and provide them with an environment to growth more than the surrounding environment (the environment after shrub seeds enter the soil is more favourable for the growth of plants) [13][14][15]. Therefore, some researchers believe that under some natural conditions, such as in semi-arid areas, shrubs can restore vegetation [16]. The invasion of shrubs in desert steppe in Inner Mongolia simplifies community composition at different scales and increases the spatial heterogeneity of herbaceous vegetation, so the scale effect of spatial heterogeneity of herbaceous vegetation in desert steppe mainly depends on whether the plant community is dominated by shrubs or grass [17]. ...
... A mechanical sampling method was adopted. The southwest intersection in the boundary of each sample site was set as the origin of sampling coordinates (0, 0), and a 0.5 m × 0.5 m quadrat was set every 5 m, and the farthest coordinate from the origin was (16,16). Nine quadrats were taken from even lines and eight from odd lines for sampling. ...
... A mechanical sampling method was adopted. The southwest intersection in the boundary of each sample site was set as the origin of sampling coordinates (0, 0), and a 0.5 m × 0.5 m quadrat was set every 5 m, and the farthest coordinate from the origin was (16,16). Nine quadrats were taken from even lines and eight from odd lines for sampling. ...
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Background Grazing disturbance plays an important role in the desert steppe ecosystem in Inner Mongolia, China. Previous studies found that grazing affected the spatial distribution of species in a community, and showed patchiness characteristics of species under different grazing treatments. Artemisia frigida is the dominant species and semi-shrub in desert steppe, and whether grazing interference will affect the spatial distribution of A. frigida is studied. In this study, geo-statistical methods were mainly used to study the spatial distribution characteristics of A. frigida population in desert steppe of Inner Mongolia at two scales (quadrat size 2.5 m × 2.5 m, 5 m × 5 m) and four stocking rates (control, CK, 0 sheep·ha –1 ·month –1 ; light grazing, LG, 0.15 sheep·ha –1 ·month –1 , moderate grazing, MG, 0.30 sheep·ha –1 ·month –1 , heavy grazing, HG, 0.45 sheep·ha –1 ·month –1 ). Results The results showed that the spatial distribution of A. frigida tended to be simplified with the increase of stocking rate, and tended to be banded with increased spatial scale. The density and height of A. frigida increased with increasing scale. With increased stocking rate, the density of A. frigida population decreased linearly, while its height decreased in a step-wise fashion. The spatial distribution of A. frigida was mainly affected by structural factors at different scales and stocking rate. The density of A. frigida was more sensitive to change in stocking rate, and the patchiness distribution of A. frigida was more obvious with increase in scale. Conclusions Stocking rate has a strong regulatory effect on the spatial pattern of A. frigida population in the desert steppe. Heavy grazing reduced the spatial heterogeneity of A. frigida in the desert steppe. The smaller dominant populations are unfavourable for its survival in heavy grazing condition, and affects the stability and productivity of the grassland ecosystem.
... Neste sentido, é importante determinar se o estabelecimento de novos indivíduos está relacionado devido à melhoria das condições ambientais ou pelo aumento de propágulos sob a copa das plantas-berçário (Badano et al. 2016). As plantasberçário são aquelas que desempenham um papel importante na recuperação das funções em ecossistemas, sendo consideradas importantes para o avanço da sucessão ecológica (Ren et al. 2008). As plantas-berçário podem interceptar sementes dispersas de outras espécies e acumula-las sob suas copas e, ainda, podem oferecer melhores condições ambientais sob suas copas regulando a luminosidade, a disponibilidade de nutrientes e umidade (Padilla & Pugnaire 2006). ...
... O favorecimento das condições sob a copa de algumas espécies pode ocorrer pelo aumento da deposição de serapilheira, resultando na cobertura do solo auxiliando, na manutenção da umidade e em microambientes melhorados e enriquecidos com nutrientes que estimulam a formação de núcleos de vegetação (Silva et al. 2015). A nucleação é importante para manutenção da diversidade biológica, produtividade de biomassa, por contribuírem significativamente para a variação espacial da produtividade e diversidade em escala local e regional (Ren et al. 2008, Reis et al. 2010, Passos et al. 2014. ...
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This study verified the differences in richness, density and species composition of the seed bank under the canopy s tree species and the adjacent field area and the relationship of total stem height and crown area to density and richness bank seeds. The seed bank was collected under the canopy of 10 individuals of each species (Curatella americana L., Luetzelburgia auriculata (Allemão) Duckee, Copernicia prunifera (Mill.) H.E.Moore)), and at 10 points in an adjacent field area. The density and richness of the seed bank was larger under the crowns of the species. The total stem height showed a positive relationship with richness and density of the seed bank, and a canopy area negative relationship. The tree species studied enhance the generation of seed bank, increasing its richness and density. They also influence species distribution and local diversity. Keyword: ecological succession; facilitation; germination
... Due to the vulnerability and geographic restriction of the species, it is important to investigate how its occurrence allows the formation of vegetation nuclei with species that coexist in the environment, promoting the processes of ecological succession and expansion of vegetation, the autoecology and preservation of the species, and consequently the influence on synecology in the environments in which it occurs. Thus, the concept of associated species is applied, which are plants that facilitate the growth and development of other plant species (target species) below their canopy, by offering favorable microhabitats for seed germination and/or seedling recruitment than the surrounding environment (REN et al., 2008). ...
... Management strategies influence competitive interactions, and structural properties are affected by vertical and horizontal forest structures. Thus, the associated species can create adequate conditions for the growth and survival of other plants under their canopies (REN et al., 2008). In addition, information on associated species can contribute to the colonization of degraded areas (RUWANZA, 2019). ...
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Species associated with Curitiba prismatica (D. Legrand) Salywon & Landrum in a Faxinal system. Curitiba prismatica, belonging to the family Myrtaceae, is an endemic species of Araucaria mixed forest (AMF) areas whose leaf essential oils have pharmaceutical properties. The objective of this study was to describe the floristic aspects, diversity, competition and diametric transition of the species associated with C. prismatica in an Araucaria mixed forest area exploited in the Faxinal system. A survey of 35 sample units was carried out using the Prodan method, classifying them as initial (pioneer and early secondary) and late (old secondary and climax). Two hundred ten trees were observed, divided into 16 botanical families, 23 genera and 29 species, with the most associated species being: C. prismatica, Casearia oblique, Casearia sylvestris, Cinnamodendron dinisii (30. Ocotea odorifera, and Casearia decandra. The Shannon (H') and Simpson (C) indices of the associated species were 2.54 nats.ind-1 and 0.14 nats.ind-1, respectively. According to the competition rates denoted by the indices of basal area (BAL), Glover and Hool (IGH) and Hegyi, competition of C. prismatica occurred with greater intensity in trees with DBH ≤ 25 cm. The results provide a better understanding of the ecological behavior of species associated with C. prismatica in AMF areas subject to Faxinal systems.
... Competitive dominant species in an ecosystem can provide strong resistance to the recruitment of small subdominant species, resulting in restoration failures (Fynn et al. 2009;Bakker et al. 2003;Flory and Clay 2010;Guido et al. 2019). Numerous studies have shown that established grass plants can either facilitate seed germination and seedling establishment by creating a favourable microclimate through shade and moisture retention (Rees and Brown 1991;Brooker et al. 2008;Tedder et al. 2011;Ren et al. 2008), or can be territorial and inhibit seed germination and seedling establishment through shading, direct root competition and allelopathy (Schenk and Jackson 2002;Guido et al. 2019;Dear et al. 1998). Dear et al. (1998) showed that established Phalaris grass swards (Phalaris aquatica) reduced the emergence and early growth of other grass species through competition for water and light. ...
... In this study, nurse plant theory could explain vetiver facilitation of seed emergence. Nurse plants theory suggests that plants can create a favourable environment through shade and moisture retention, resulting in an increased emergence and seedling establishment around them (Fowler 1986b;Ren et al. 2008). Many well-studied abiotic factors that affect seedling emergence can be altered by established neighbouring plants e.g. ...
Species-rich grasslands provide important ecosystem services, and in South Africa, approximately 40% of these grasslands are degraded. Vetiver grass (from India) is often used during rehabilitation efforts to restore soil function without a thorough understanding of the potential negative ecological impacts. Hence, a study was initiated to investigate vetiver’s ecological impacts during grassland rehabilitation. Firstly, a field survey was conducted using a contiguous quadrat method to evaluate the extent of grass secondary succession in these rehabilitated sites. Secondly, the effect of vetiver competition and seed sowing method on the recruitment of two native grasses (Eragrostis curvula and Megathyrsus maximus) was examined using pot trials. The field survey results showed no evidence of grass secondary succession, but rather the abundance of bare ground around vetiver, and a marked increase in grass species richness with increasing distance from planted vetiver. Subsequently, in the pot trial, vetiver facilitated emergence in both native grasses, and soil surface sowing of indigenous grass seeds showed greater emergence than other sowing methods. However, vetiver inhibited native grass seedling establishment, even when root competition was excluded. This study suggests that areas rehabilitated using vetiver are unlikely to become productive grasslands with good grazing, because vetiver inhibits colonisation by native grasses.
... Shrub species are commonly planted to combat desertification. Legumes are potential nurse plants that can improve the survival and growth of other species due to their ability to fix nitrogen (Ren et al., 2008;Reynolds et al., 1999;Zhao et al., 2007). Unpalatable native species that could be planted in heavily grazed sites are recommended as nurse plants as they can help create microhabitats for the rehabilitation of other plants (Ren et al., 2008;Smit et al., 2006). ...
... Legumes are potential nurse plants that can improve the survival and growth of other species due to their ability to fix nitrogen (Ren et al., 2008;Reynolds et al., 1999;Zhao et al., 2007). Unpalatable native species that could be planted in heavily grazed sites are recommended as nurse plants as they can help create microhabitats for the rehabilitation of other plants (Ren et al., 2008;Smit et al., 2006). Two shrub species, C. microphylla and C. fruticosum, were classified as unpalatable or less palatable species in this study. ...
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Hulunbuir steppe, one of the four largest steppes in China, has experienced rapidly progressing desertification partly due to overgrazing by livestock. The objective of this study was to investigate the effectiveness of various vegetation recovery methods, including the selection of unpalatable plants less affected by grazing livestock. To determine livestock grazing preferences at Hulunbuir restoration sites, we used DNA barcoding methods to analyze fecal materials of horses and cattle grazing on four restored plants: two trees (Pinus sylvestris L. var. mongolica and Populus canadensis) and two shrubs (Caragana microphylla and Corethrodendron fruticosum). Neither of the two tree species were detected in livestock feces, whereas both shrub species were detected at lo w frequencies. There were no significant differences in compositions of species consumed by horses and cattle except that Asteraceae species were more often consumed by cattle. Our results showed that the four plants used for restoration may be classified as unpalatable or less palatable species in the Hulunbuir restoration area. Our results may help inform restoration strategies implemented in restoration areas, especially regarding negative effects of livestock grazing during the initial stage of restoration in Hulunbuir.
... Castanopsis species belonging to Fagaceae family are usually large canopy trees, widespread generalists growing in different habitats with varying altitudes and soil types (Dong et al., 2009;Cheuk and Fischer, 2021). Some species in the Castanopsis genus are comparatively fast-growing, suitable for controlling soil erosion and reforestation (Ren et al., 2008;Dong et al., 2009;Cheuk and Fischer, 2021). For instance, Castanopsis rockii, an endemic woody species and a potential Tuber host, is widely utilized as a timber tree, in Yunnan, China. ...
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Black truffles and white truffles are widely studied around the world, but their effects on plant growth and physiological responses, and on the mycorrhizosphere bacterial community of the host plant remain unclear. Here, mycorrhizal colonization of Castanopsis rockii by Tuber indicum (Chinese black truffle) and T. lijiangense (Chinese white truffle), respectively, was induced in a greenhouse study, and their effects on host growth, physiological responses and mycorrhizosphere bacterial communities were compared. The results show that colonization of both Tuber species significantly increased leaf photosynthetic rate, leaf P concentration and mycorrhizosphere acid phosphatase activity, as well as richness of mycorrhizosphere bacterial communities of C. rockii seedlings. However, T. indicum colonization on the one hand significantly decreased tartrate content, bacterial acid phosphatase, phoC gene abundance in the mycorrhizosphere, and peroxidase (POD) activity of ectomycorrhizal root tips, but on the other hand increased mycorrhizosphere pH and superoxide dismutase (SOD) of ectomycorrhizal root tips, compared to T. lijiangense colonization. Moreover, principal coordinate and β-diversity analyses show significant differences in mycorrhizosphere bacterial community composition between T. indicum and T. lijiangese colonized C. rockii seedlings. Finally, the relative abundance of the bacterium Agromyces cerinus significantly correlated to mycorrhizosphere acid phosphatase activity and leaf P concentration, suggesting that this bacterium might play an important role in P mobilization and acquisition. Overall, these results suggest that T. indicum and T. lijiangense differently regulate their host plant's physiological responses and mycorrhizosphere bacterial community.
Restoration ecology is an interdisciplinary field of research that builds on the concepts and foundations of ecology and makes use of other disciplines of the natural and social sciences in both theory and practice. After a brief historical overview of restoration ecology or ecosystem restoration, important basic ecological terms and key concepts, as well as the concepts of ecosystem services and ecosystem degradation, are explained. As a basis for this interdisciplinary textbook, ecosystem restoration is defined to embed the numerous approaches to restoration for Central European ecosystems and land-use systems, respectively, in a comprehensive framework.
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Non-hydrophyte species experience the re-flooding hypoxic conditions in wetland; however, how they exist in wetland is still not well studied. A field experiment was developed in Jinchuan wetland with different water level conditions (high water level: 6–7 cm; low water level: 1.5–2.5 cm). The above-ground biomass, the heights and areas of tussocks, and the names and number of species on each tussock were measured, and the proportions of non-hydrophyte species (PNH) were calculated. In the high water level condition, tussocks accumulated more biomass, increased the heights and reduced the areas. Importantly, PNH were significantly higher in the high water level condition compared with low water level condition (51.22 ± 11.26% vs 45.95 ± 14.02%). Interestingly, the number of non-hydrophyte species and PNH decreased with the increasing of the heights of tussocks and the decreasing of the areas of tussocks. Overall, tussocks could grow well and provide living space for non-hydrophyte species in re-flooding condition; thus, tussocks could be regarded as nurse plants, which is a new mechanism of non-hydrophyte species to exist in wetland. Moreover, it is valuable to know non-hydrophyte species preferred to grow on lower and bigger tussocks for wetland management. Degradation in Jinchuan wetland can be retarded through controlling the morphological characteristics of tussocks.
Seven man-made broad-leaved mixed forests with an area of 6.4 ha were established in 1964-1979 on an extremely degraded land in south China. The number of species and individuals and Shannon-Wiener Index (H) of the plantations increased gradually after afforestation. The H value of some of the plantations were close to that of the secondary forest. A total of 47 native species invaded and some planted species disappeared in the plantations in 30 years. However, no tree invaded the contrasting barren land since reforestation. This suggested that the process of natural restoration of the tropical seasonal rain forest is a potentially slow process in the extremely degraded ecosystem, but plant diversity of tropical seasonal rain forest can be restored after afforestation in natural condition. Natural succession cannot be considered as a useful management option in extremely degraded region.
In a mixed desert shrub community we removed and added shrub canopies to examine above- and belowground influences of 3 species of shrubs on islands of soil fertility and the survival of transplanted Ambrosia dumosa seedlings. Soils sampled under shrubs in the wet season had higher pH, water content, organic matter, and both total and mineralizable nitrogen than soils in adjacent open areas, confirming a widely established pattern in arid lands. However, we also found species differences in soil parameters. Soils under Coleogyne ramosissima had highest pH, soils under A. dumosa had highest water content and nitrogen mineralization rates, and soils under Larrea tridentata had lowest water content. Soils sampled under shrubs in the dry season, 7 months after experimental shrub removal maintained higher organic matter and total and mineralizable nitrogen content than adjacent open soils, but pH and water were altered by shrub manipulations. Species differences persisted only in soil water levels (A. dumosa soils were driest). Over a 1-year period, transplanted A. dumosa seedlings had highest survivorship in shrub removal and open treatments and died most rapidly under control shrubs of all 3 species, suggesting that shrubs had a strong negative effect on seedling survival, even in the presence of higher organic matter, nutrients, and (initially) higher water content of fertile islands. Our results suggest that nurse plants and islands of soil fertility have the potential to facilitate growth of other species by nutrient additions, but that the net effect of nurse plants can be negative due to shading and/or root competition.
In contrast to documented increases in woody plant dominance of savannas and grasslands of North America, oak (Quercus L.) savannas that form lower tree lines in the southwestern United States and northwestern Mexico have been stable over the last several centuries. We sought to identify potential biotic and abiotic constraints on seedling recruitment of Quercus emoryi within the context of potential shifts in lower tree line. We used held surveys to describe seedling distribution at and below lower tree line, and to determine the potential. for acorn dispersal from lower tree line into adjacent grassland. Field and greenhouse experiments were used to test explanatory hypotheses generated by descriptive surveys. Q. emoryi seedlings were located almost exclusively beneath mature, conspecific tree canopies within the woodland and savanna and were absent from adjacent semidesert grassland in 1993 and 1995. Seed bank surveys indicated that acorns were concentrated beneath tree canopies and were dispersed into adjacent grassland in low numbers. Although soil N, C, and P were about two times greater beneath trees than in adjacent grassland, experimental nutrient amendments to subcanopy and grassland soils indicated that soil nutrients did not limit Q. emoryi growth. Reciprocal transfers of subcanopy and grassland soil to subcanopy and grassland microsites indicated that microsite was more important than soil source for seedling growth. Overstory shade was important at all stages of seedling development investigated: the provision of artificial or natural shade increased rates of seedling emergence and subsequent survival as much as 19-fold and increased recruitment rates between 30- and 60-fold. We conclude that rates of Q. emoryi recruitment within grasslands below tree line are relatively low and are constrained by low rates of seed dispersal coupled with a low probability of seedling emergence. In contrast, large numbers of acorns are dispersed directly beneath Q. emoryi trees, where they have a higher probability of emergence than in adjacent grassland. Survival rates of emerged seedlings were low, regardless of landscape position. Thus, observed patterns of seedling distribution on the landscape resulted from interactions between seed dispersal and habitat-specific response of seedlings to environmental variation. Results of this and complementary research suggest that the lower tree line in southern Arizona is stabilized by self-enhancing feedback mechanisms of overstory shade, seed dispersal, and seedling establishment, coupled with strong abiotic constraints beyond the current ecotone. These processes stabilize the woodland-grassland ecotone both spatially and temporally, consistent with Wilson and Agnew's one-sided positive feedback switch. Although this switch would not produce an indefinitely stable vegetation mosaic, upslope or downslope shifts in lower tree line are apparently resistant to decadal or even century-scale climatic perturbation. The observed shift in tree line in the last millennium was less likely the result of slow, spatial progression of autogenic safe sites than the result of episodic and infrequent allogenic processes that simulated or negated the importance of conspecific, biogenic safe sites.
The establishment phase of Neobuxbaumia tetetzo, a giant columnar cactus, occurs mostly beneath the canopies of trees and shrubs which act as nurse plants. This pattern cannot be attributed to preferential seed dispersion, as Neobuxbaumia fruits open while still on the plant, dropping c1000 seeds fruit-1 randomly around the parent plant. Mimosa luisana is the most abundant shrub in the community. Seed germination was lowest in open spaces. In all treatments, exclusion from predators significantly increased seedling survival. Only shaded treatments had live individuals at the end of the experiment, 2 yr later. Results suggest that the nurse-plant effect between N. tetetzo and M. luisana is chiefly the result of differential survival in shaded microsites with less direct solar radiation, and consequently with lower daytime temperatures and lower evaporative demand. Field samplings were conducted in two Mexican deserts located outside the tropical belt: the Vizcaino Desert in Baja California and the Gran Desierto de Altar in Sonora. In these deserts direct solar radiation has a southern azimuth all year round. Five of six succulent species analysed showed a significant pattern of greater establishment on the shaded north sides of nurse plants. -from Authors
After a millenarian history of overexploitation, most forests in the Medi- terranean Basin have disappeared, leaving many degraded landscapes that have been re- colonized by early successional shrub-dominated communities. Common reforestation tech- niques treat these shrubs as competitors against newly planted tree seedlings; thus shrubs are cleared before tree plantation. However, empirical studies and theory governing plant- plant interactions suggest that, in stress-prone Mediterranean environments, shrubs can have a net positive effect on recruitment of other species. Between 1997 and 2001, we carried out experimental reforestations in the Sierra Nevada Protected Area (southeast Spain) with the aim of comparing the survival and growth of seedlings planted in open areas (the current reforestation technique) with seedlings planted under the canopy of preexisting shrub species. Over 18 000 seedlings of 11 woody species were planted under 16 different nurse shrubs throughout a broad geographical area. We sought to explore variation in the sign and magnitude of interactions along spatial gradients defined by altitude and aspect. In the present work, we report the results of a meta-analysis conducted with seedling survival and growth data for the first summer following planting, the most critical period for reforestation success in Mediterranean areas. The facilitative effect was consistent in all environmental situations explored (grand mean effect size d 1 5 0.89 for survival and 0.27 for growth). However, there were differences in the magnitude of the interaction, depending on the seedling species planted as well as the nurse shrub species involved. Additionally, nurse shrubs had a stronger facilitative effect on seedling survival and growth at low altitudes and sunny, drier slopes than at high altitudes or shady, wetter slopes. Facilitation in the dry years proved higher than in the one wet year. Our results show that pioneer shrubs facilitate the establishment of woody, late-successional Mediterranean spe- cies and thus can positively affect reforestation success in many different ecological settings.