Environmental Engineering Reference
In-Depth Information
Species facilitation is due to neighboring plants mitigating environmental stress including abiotic
stresses such as salinity, flood, nutrient, sea wave stress and biotic stresses such as herbivory,
pollination and dispersal stress in order to promote fitness of target plant.
Figure 1. Key mechanisms of direct plant-plant facilitation in coastal wetlands.
E
XPERIMENTAL
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PPROACHES TO
S
TUDYING
P
LANT
-P
LANT
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ACILITATION
In contrast to studies on other ecosystems (
e.g
., semiarid grasslands or alpine plant
communities) which have employed removal experiments to investigate plant-plant
facilitation (
e.g
., Choler et al. 2001), studies in coastal wetland employed transplant
experiments. Removal experiments involve the elimination of all neighboring plants around
the target individual. Target plant performance is then compared between removal and control
treatments. In transplant experiments, patches of conspecific individuals are transplanted into
another plant zone (with or without neighboring plants). Then plant performance is compared
between transplant and control treatments. Both experimental approaches are popular
methods for detecting of plant-plant facilitation, and both have their own advantages and
disadvantages.
Removal experiments are suitable for species with a scattered distribution, but can only
be operated on widely spread species. Moreover, it is impossible to detect species-specific
interactions in removal experiments. On the other hand, transplant experiments can only be
conducted on densely populated species and are inappropriate for species with a scattered
population distribution population (except when cultivating seedlings). Approaches such as
spatial point process, Hierarchical Bayesian analysis which was designed to investigate
community-level (larger than only one or a few pairs of species in the community)
consequences of species interactions (Raventos et al. 2010; Wang et al. 2011) are rarely used
