Soil Ecology Wiki - User contributions [en]

Microclimate

2021-05-14T20:27:25Z

Ajacobs5: /* References */

Microclimate is the set of atmospheric conditions that occur in a local area as a result of environmental heterogeneity near the Earth’s surface. Microclimates play an integral role in ecosystem processes. Microclimatic variations in energy and moisture directly affect a number of key ecological processes in forest ecosystems occurring at multiple spatial and temporal scales. [[File:Microclimate1.png|400px|thumb|right|Schematic of microclimatic processes relating to heat and water transfer of an organism, [1] ]]
==Influences on Microclimate==
The two major sources of microclimate variability are differences in energy and moisture, or temperature and humidity. Differences in temperature and humidity can have numerous drivers, including aspect, (direction that a slope faces,) elevation, successional stage, vegetation and canopy presence[4,5]. The presence of bodies of water can influence microclimate, as they may increase humidity and stabilize temperature. Presence of herbaceous and woody vegetation can also greatly influence microclimate, as they create structure and shade. [2]
==In Soils==
Consideration of the microclimate is particularly important in [[soil]] [[ecology]], as the heterogenous nature of soil means that numerous microclimates are present in very small areas of soils. Microclimate, especially temperature and moisture, regulates activity rates of decomposers[7]. High fluctuations in microclimate has been shown to lead to high [[moss|bryophyte]] diversity. [6] This high heterogeneity of conditions may contribute to high overall [[biodiversity interactions|soil biodiversity]] as well.

Soil microclimate can affect macroaggregate dynamics and [[Aggregate formation]].[3] Soil erodability is reduced in warmer climates, which prevents the occurrence of fragile microaggregates caused by freeze-thaw events. Soil texture greatly influences local microclimate by regulating availability of surface water films and water-holding capacity [7].

==References==
1. Kearney, M. R., Isaac, A. P. & Porter, W. P. microclim: Global estimates of hourly microclimate based on long-term monthly climate averages. ''Sci Data'' '''1''', 140006 (2014).

2. Breshears, D. D., Nyhan, J. W., Heil, C. E. & Wilcox, B. P. Effects of Woody Plants on Microclimate in a Semiarid Woodland: Soil Temperature and Evaporation in Canopy and Intercanopy Patches. ''International Journal of Plant Sciences'' '''159''', 1010–1017 (1998).

3. Cécillon, L., de Mello, N. A., De Danieli, S. & Brun, J.-J. Soil macroaggregate dynamics in a mountain spatial climate gradient. ''Biogeochemistry'' '''97''', 31–43 (2010).

4. Tsuyuzaki, S., Matsuda, M. & Akasaka, M. Effect of a deciduous shrub on microclimate along an elevation gradient, Mount Koma, northern Japan. ''Clim. Res''. '''51''', 1–10 (2012).

5. Frey, S. J. K., Hadley, A. S. & Betts, M. G. Microclimate predicts within-season distribution dynamics of montane forest birds. ''[[Diversity]] Distrib''. '''22''', 944–959 (2016).

6. Kraichak, E. Microclimate Fluctuation Correlated with Beta Diversity of Epiphyllous Bryophyte Communities. ''Biotropica'' '''46''', 575–582 (2014).

7. Coleman, David C., Callaham Jr., Mac A., and Crossley Jr., D. A. “Fundamentals of [[Soil Ecology]], Third Edition.” 2018. Academic Press. Cambridge, MA.

2021-05-05T18:06:17Z

Ajacobs5:

Allelopathy (Gr: allelon (of each other) and pathos (to suffer)) is broadly defined as any chemical-mediated interaction among plants, though it is typically thought of as a mechanism of inhibition. [1] The term allelopathy was coined in 1937 by Hans Molisch to refer to any biological interactions between all types of plants, but was refined by Rice in 1974 as “any direct or indirect harmful effect by one plant (including [[microorganisms]]) on another through production of chemical compounds that escape into the environment.” [2]
[[File:Allelopathy-factors-processes.png|400px|thumb|right|Overall processes of allelopathy and factors affecting allelopathy. This figure describes the way of allelochemical production from the plant, i.e., leaches from the aerial parts, root exudates, transpiration, and stem flow. In addition, it also reports that allelochemical compounds mostly include phenolic compounds, terpenes, and fatty acids which suppress the weeds and cause improvement in the production of crop. Noor et al. 2016]]
== Mechanism ==
Allelopathy is caused by the release of secondary compounds into the [[soil]]. Secondary compounds allow plants to behave plastically in numerous ways.[3] The effect of allelopathy depends on a chemical being added to the environment, distinguishing this form of interference from competition1. [[Flavonoids]], for example, act as a signaling agent and chelation agent while also playing a role in plant defense.

== Evolution ==
Generally, the secondary metabolites that act as allelochemicals serve other purposes in the plants function; natural selection should favor secondary metabolites with multiple functions because they protect the plants against a variety of unpredictable biotic and abiotic environments.[4]
Allelopathy may also drive evolution in the neighbors of allelopathic plants as well: one study found that individuals grown from seeds of parents that have survived exposure to allelochemicals in ''Centaurea stoebe'' have exhibited much higher resistance to the general competitive effects of Centaurea, the root exudates from Centaurea, and to a chemical speciﬁc to the root exudates of ''Centaurea'' ( ± )-catechin relative to other native species that have not previously encountered ''Centaurea maculosa''[5].

== Ecology ==
Chemicals produced by plants have strong effects on ecosystem [[properties]], altering [[rhizosphere]] chemistry, chelating metals, altering soil community interactions, and shifting plant community interactions [6].

=== Role in Biological Invasion ===
A comparison of exotic plant species that are highly invasive in North America with exotics that are widespread, but non-invasive revealed that the invasive plants were more likely to have secondary compounds that have not been reported from North American native plants.[7]
According to the Novel Weapons Hypothesis, invasive species possess novel weapons in the form of chemicals that suppress the growth of neighboring plants in an alien environment, allowing them to spread and form their own monocultures. In the native range, such species grow normally in association with other plants. Seemingly, the native plants’ tolerance evolves toward chemicals or the so-called novel weapons on account of their long association. [8]

== References ==
1. Rice, E. L. ALLELOPATHY - AN OVERVIEW. 2.

2. Amb, M. K. & Ahluwalia, A. S. Allelopathy: Potential Role to Achieve New Milestones in Rice Cultivation. Rice Science 23, 165–183 (2016).

3. Metlen, K. L., Aschehoug, E. T. & Callaway, R. M. Plant behavioural [[ecology]]: dynamic plasticity in secondary metabolites. Plant, Cell & Environment 32, 641–653 (2009).

4. Izhaki, I. Emodin - a secondary metabolite with multiple ecological functions in higher plants. New Phytol 155, 205–217 (2002).

5. Callaway, R. M. Natural selection for resistance to the allelopathic effects of invasive plants. natural selection 8 (2005).

6. Inderjit, Wardle, D. A., Karban, R. & Callaway, R. M. The ecosystem and evolutionary contexts of allelopathy. Trends in Ecology & Evolution 26, 655–662 (2011).

7. Cappuccino, N. & Arnason, J. T. Novel chemistry of invasive exotic plants. Biol. Lett. 2, 189–193 (2006).

8. Batish, D., Singh, H., Kaur, S. & Kohli, R. Novel weapon hypothesis for the successful establishment of invasive plants in alien environments: A critical appraisal. in Invasive Plant Ecology 19–28 (CRC Press, 2013). doi:10.1201/b13865-4.

File:Allelopathy-factors-processes.png

2021-05-05T18:05:07Z

Ajacobs5: Overall processes of allelopathy and factors affecting allelopathy. This figure describes the way of allelochemical production from the plant, i.e., leaches from the aerial parts, root exudates, transpiration, and stem flow. In addition, it also report...

Overall processes of allelopathy and factors affecting allelopathy.
This figure describes the way of allelochemical production from the plant,
i.e., leaches from the aerial parts, root exudates, transpiration, and stem
flow. In addition, it also reports that allelochemical compounds mostly
include phenolic compounds, terpenes, and fatty acids which suppress the
weeds and cause improvement in the production of crop. Noor et al. 2016

Microclimate

2021-05-05T17:58:48Z

Ajacobs5:

File:Microclimate1.png

2021-05-05T17:56:40Z

Ajacobs5: Schematic of microclimatic processes relating to heat and water transfer of an organism

Schematic of microclimatic processes relating to heat and water transfer of an organism

Allelopathy

2021-05-05T17:42:05Z

Ajacobs5:

Allelopathy (Gr: allelon (of each other) and pathos (to suffer)) is broadly defined as any chemical-mediated interaction among plants, though it is typically thought of as a mechanism of inhibition. [1] The term allelopathy was coined in 1937 by Hans Molisch to refer to any biological interactions between all types of plants, but was refined by Rice in 1974 as “any direct or indirect harmful effect by one plant (including [[microorganisms]]) on another through production of chemical compounds that escape into the environment.” [2]

== Mechanism ==
Allelopathy is caused by the release of secondary compounds into the [[soil]]. Secondary compounds allow plants to behave plastically in numerous ways.[3] The effect of allelopathy depends on a chemical being added to the environment, distinguishing this form of interference from competition1. [[Flavonoids]], for example, act as a signaling agent and chelation agent while also playing a role in plant defense.

== Evolution ==
Generally, the secondary metabolites that act as allelochemicals serve other purposes in the plants function; natural selection should favor secondary metabolites with multiple functions because they protect the plants against a variety of unpredictable biotic and abiotic environments.[4]
Allelopathy may also drive evolution in the neighbors of allelopathic plants as well: one study found that individuals grown from seeds of parents that have survived exposure to allelochemicals in ''Centaurea stoebe'' have exhibited much higher resistance to the general competitive effects of Centaurea, the root exudates from Centaurea, and to a chemical speciﬁc to the root exudates of ''Centaurea'' ( ± )-catechin relative to other native species that have not previously encountered ''Centaurea maculosa''[5].

== Ecology ==
Chemicals produced by plants have strong effects on ecosystem [[properties]], altering [[rhizosphere]] chemistry, chelating metals, altering soil community interactions, and shifting plant community interactions [6].

=== Role in Biological Invasion ===
A comparison of exotic plant species that are highly invasive in North America with exotics that are widespread, but non-invasive revealed that the invasive plants were more likely to have secondary compounds that have not been reported from North American native plants.[7]
According to the Novel Weapons Hypothesis, invasive species possess novel weapons in the form of chemicals that suppress the growth of neighboring plants in an alien environment, allowing them to spread and form their own monocultures. In the native range, such species grow normally in association with other plants. Seemingly, the native plants’ tolerance evolves toward chemicals or the so-called novel weapons on account of their long association. [8]

== References ==
1. Rice, E. L. ALLELOPATHY - AN OVERVIEW. 2.

2. Amb, M. K. & Ahluwalia, A. S. Allelopathy: Potential Role to Achieve New Milestones in Rice Cultivation. Rice Science 23, 165–183 (2016).

3. Metlen, K. L., Aschehoug, E. T. & Callaway, R. M. Plant behavioural [[ecology]]: dynamic plasticity in secondary metabolites. Plant, Cell & Environment 32, 641–653 (2009).

4. Izhaki, I. Emodin - a secondary metabolite with multiple ecological functions in higher plants. New Phytol 155, 205–217 (2002).

5. Callaway, R. M. Natural selection for resistance to the allelopathic effects of invasive plants. natural selection 8 (2005).

6. Inderjit, Wardle, D. A., Karban, R. & Callaway, R. M. The ecosystem and evolutionary contexts of allelopathy. Trends in Ecology & Evolution 26, 655–662 (2011).

7. Cappuccino, N. & Arnason, J. T. Novel chemistry of invasive exotic plants. Biol. Lett. 2, 189–193 (2006).

8. Batish, D., Singh, H., Kaur, S. & Kohli, R. Novel weapon hypothesis for the successful establishment of invasive plants in alien environments: A critical appraisal. in Invasive Plant Ecology 19–28 (CRC Press, 2013). doi:10.1201/b13865-4.