As soil engineers, termites play a key role in the functioning of many tropical and subtropical ecosystems. This reviews assesses advances in our knowledge of the beneficial influences of termites on ...ecosystem functioning and services. Termites are amongst the main macroinvertebrate decomposers in arid and semi-arid environments, and exert additional impacts through the creation of biostructures (mounds, galleries, sheetings, etc…) with different soil physical and chemical properties. They influence the distribution of natural resources such as water and nutrients in the landscape and consequently the diversity of soil microbes, plants and animals. Surprisingly, considering the wide range of ecosystem services provided by termites, few researches have been reported on the utilization of termite activity for the management of soil fertility or for the rehabilitation of degraded soils. In our final section, we discuss the main obstacles hampering the development of such approaches and we suggest that ecosystems services provided by termites are not sufficiently appreciated, especially in the context of long-term processes and possible biotechnologies derived from a detailed knowledge of their biology.
► This review deals with the influences of termites on ecosystem functioning. ► Termites act as ecosystem engineers in arid and semi-arid environments. ► They can be of significant interests for the promotion of ecosystem services.
Macrotermes termitaria are conspicuous features of savannah ecosystems in the Sudanian and Sahelian zones of West Africa. The mounds, alive or abandoned, are a major source of heterogeneity in the ...landscape. The purpose of the present study was to assess the impact of termitaria on tree community in a state forest of the Sudanian regional centre (Tiogo forest, Burkina Faso), under controlled burning and grazing experiments. A comparative inventory was carried out in a split-plot experiment (16 subplots of 2500
m
2): 8 subplots where fire regime and grazing were controlled and 8 subplots exposed to grazing and with annual prescribed fire since 1992. All tree individuals (≥1.5
m) were recorded, both on termitaria and outside and their basal area at stump level was measured. A total of 61 observed (or 65.7
±
2.4 estimated) tree species were recorded on 28
Macrotermes subhyalinus mounds (54 observed species or 60.8
±
3.3 estimated), the immediate surroundings (44 observed and 59.0
±
0.0 estimated species) and the rest of subplots (56 observed and 63.6
±
0.0 estimated). Specific density was higher on mounds in comparison with the surroundings (
P
<
0.05). Results showed that termitaria played a key role in maintaining higher species diversity as compared to their surroundings (
P
<
0.05). Differences in species diversity between termitaria and immediate surroundings appeared more pronounced in disturbed plots (submitted to both fire and grazing). Some species, such as
Tamarindus indica,
Boscia senegalensis,
Cadaba farinosa,
Capparis sepiaria and
Maerua angolensis are found solely on termitaria. Besides, the density of trees was significantly higher on termitaria compared to the surrounding (
P
<
0.05), as well as total basal area per unit of 100
m
2 area (
P
<
0.05). We concluded that
Macrotermes termitaria play an important role as a source of heterogeneity in this Sudanian savannah woodland ecosystem. This role is particularly important in ecosystems under stresses. Termitaria acted as refuge for tree vegetation. The density and dynamics of
M. subhyalinus termitaria should, therefore, be taken into account in the global strategy of the forest resources management and conservation.
•Soil hydrostructural properties of termite mounds were compared.•Soils from termite mounds were more compact than their surrounding control soils.•Cathedral mounds had lower macroporosity than the ...control soil.•Soils from lenticular mounds had a higher microporosity than the control soil.•Soils from lenticular mounds had a higher water holding capacity than the control soil.
Mounds built by fungus-growing termites are often considered to be patches or fertile areas in tropical ecosystems because they contain more nutrients than the surrounding soil environments. However, the mechanism of how these habitats influence soil physical properties remains unknown. Therefore, this study aimed at comparing the soil hydrostructural properties of two common termite mounds in southern India, namely, cathedral and lenticular mounds. The shrinkage curves of the soil eroded from three cathedral mounds and of the soil sampled in the center or in the periphery of three lenticular mounds were measured and compared to those of their surrounding soil environment. This study revealed that the soil in the periphery of cathedral mounds was compact with a lower soil specific volume and macroporosity than the control soil. On the other hand, the accumulation of clay in lenticular mounds was associated with a lower soil specific volume at the end of the shrinkage period, higher microporosity, increased swelling capacity and higher water holding capacity than the control soil. These parameters reached intermediate values in the periphery of the lenticular mounds between those of the lenticular mound soil and the surrounding control soil. In conclusion, this study showed that cathedral and lenticular mounds impacted soil hydrostructural properties in two opposing directions. It also highlighted the link between the impact of termites on the clay and carbon contents of soil and their influence on soil porosity and water dynamics, and then the need for a better understanding of the influence of termites on the dynamic of carbon and clay in ecosystems.
•Termites have harmful (their dark side) and beneficial (their bright side) impacts on SGDs.•Negative impacts are mainly linked with their status as pests (SDGs 1–3).•Positive impacts concern SDGs ...1–3, 9, 13 and 15.•The dilemma between harmful and beneficial impacts are intertwined and both are needed for the sustainable management of ecosystems.
Termites are amongst the main macroinvertebrate decomposers in tropical ecosystems and they exert additional impacts through the creation of biostructures (mounds, galleries, sheetings, etc.) with different soil physical and chemical properties, thereby impacting positively on numerous ecosystem services for humankind. Unfortunately, this positive or ‘bright’ role of termites is often overshadowed by their ‘dark’ side, that is, their status as pests threatening agriculture and constructions. This article assesses advances in our knowledge of the impact of termites on several sustainable development goals (SDGs 1 ‘no poverty’, 2 ‘zero hunger’, 3 ‘good health’, 9 ‘innovation’, 11 ‘sustainable cities’, 13 ‘climate action’ and 15 ‘life on land’). Finally, using the Indian myth of Valmiki as a parable, we illustrate that a reconciliation between the termite's dark and bright sides is needed if we want to reduce our dramatic impact on biodiversity and more generally achieve SDGs.
•Termites are commonly differentiated into feeding and building groups.•Sheeting properties are mainly explained by the properties of the environment.•Building strategy better explains sheeting ...properties.•Redefining groups using a trait-based approach is proposed as perspective.
Termites are key soil bioturbators in tropical ecosystems. Apart from mound nests constructed by some advanced lineages, most of the species use their faeces, oral secretions, debris, or soil aggregates to protect themselves from predators and desiccation when they go out to forage. Although this soil ‘sheeting’ is considered to play a key role in soil functioning, the properties of this termite-made material has been poorly studied. The few available data showed that sheeting properties are highly variable with positive, neutral or negative impacts on soil C and clay content, and consequently on soil aggregate stability. Therefore, the objective of this study was to determine the factors controlling the physical (particle size fractions and structural stability) and chemical (pH, electrical conductivity and carbon content) properties of soil sheeting produced by termite species encompassing all feeding and building categories using a dataset representative of an important diversity of biotopes coming from 21 countries from all continents colonized by termites. We showed that sheeting properties were explained by the properties of their environment, and especially by those of the bulk soil (linear relationships), followed in a lesser extent by the mean annual precipitation and biotope. Classic hypotheses related to termite feeding and building strategies were not hold by our analysis. However, the distinction of termites into fungus-growing and non-fungus growing species was useful when differentiating the impact of termites on soil electrical conductivity, C content, and structural stability. The large variability observed suggests the need to redefine termite functional groups based on their impacts on soil properties using a trait-based approach from morphological, anatomical and/or physiological traits.
This article discusses the potential of Near Infrared Reflectance Spectroscopy (NIRS) for identifying termite species based on their specific molecular signatures. We compared the NIRS signatures of ...termite workers and soldiers from five species: Hodotermopsis sjoestedti, Nasutitermes lujae, Nasutitermes voeltzkowi, Microcerotermes parvus and Reticulitermes virginicus. The termite species were clearly differentiated along the first three axes of a principle component analysis. This study therefore shows the potential of the method to differentiate termite species and could constitute a cost effective and faster technology than approaches based on microsatellite and mitochondrial data. This research is a first step and further studies on a larger number of termite species and colonies sampled in situ, as well as other, difficult to identify macroinvertebrate groups will be of interest.
•Termite species have different molecular compositions.•Near Infrared Reflectance Spectroscopy (NIRS) method allows the discrimination of termite species.•Other soil invertebrates could be identified using NIRS method.
This communication assesses advances in our knowledge of the beneficial influences of termites on ecosystem functioning and services. Termites are amongst the main macroinvertebrate decomposers in ...arid and semi-arid environments and exert additional impacts through the creation of biostructures (mounds, galleries, sheetings, etc.) with different soil physical and chemical properties. Unfortunately, the positive ‘or bright’ role of termites is often overshadowed by their dark side, i.e. their status as pests threatening agriculture in the tropics (635 vs. 164 articles referenced in WoS with termites and either pest or ecosystem engineer as keywords. Source: WoS, April 2019).
Termite impacts on soil properties and water dynamics can be differentiated at four different scales: (i) at the landscape scale, where termites act as heterogeneity drivers; (ii) at the soil profile scale, where termites act as soil bioturbators; (iii) at the aggregate scale, where they act as aggregate reorganizers; (iv) and last, at the clay mineral scale, where they can act as weathering agents 1.
In this communication, two examples of ecosystem services provided by termites are given.
The first describes the positive impact of termites on water infiltration and nutrient guidance at small scale through the production of foraging galleries in soil 2 and how this activity can be used to improve agro-ecosystem functioning in arid and semi-arid environments 3.
The second example deals with the construction of mounds and sheeting by termites in “natural” environments 4 and how these “patches of biodiversity and fertility” can be used in the lower Mekong Basin to reduce food insecurity and to provide a better access to health 5 (Fig. 1).
Finally, the perception of termite mounds in Southern Indian rural environments (Fig. 2) is discussed and used as example of the cultural services that can be provided by termites in some circumstances. The story of Valmiki, the author of the Ramayana, is explained and used as a parable for highlighting the interconnection between the “bright” and “dark” sides of termites, and more generally that to get the bright we also need the dark.
Termites, herbivores and fire are recognized as major guilds that structure woody plant communities in African savanna and woodland ecosystems. An understanding of their interaction is crucial to ...design appropriate management regimes. The aim of this study was to evaluate the long-term impacts of herbivore, fire and termite activities on regeneration of trees. Permanent experimental quadrats were established in 1992 in the Sudanian woodland of Burkina Faso subjected to grazing by livestock and annual early fire and the control. Within the treatment quadrats, an inventory of the woody undergrowth community was conducted on termitaria occupied by Macrotermes subhyalinus, extended termitosphere (within 5 m radius from the mound base) and adjacent area (beyond 5 m from the mound base). Hierarchical analysis was performed to determine significant differences in species richness, abundance and diversity indices among vegetation patches within fire and herbivory treatments. Grazed quadrats had significantly (P < 0.001) more species and stem density of woody undergrowth than non-grazed quadrats but maintained similar level of species richness and stem density of woody undergrowth on termitaria. There were not significant differences (P>0.05) in species richness and stem density between burnt and unburnt quadrats. Termitaria supported a highly diverse woody undergrowth with higher stem density than either the extended termitosphere or rest of quadrats. The density of woody undergrowth was significantly related with mature trees of selected species on termitaria (R-2 = 0.593; P<0.001) than that on the extended termitosphere (R-2 = 0.333; P<0.001) and adjacent area (R-2 = 0.197; P<0.001). It can be concluded that termites facilitate the regeneration of woody species while grazing and annual early fire play a minor role in the regeneration of woody species. The current policy that prohibits grazing should be revised to accommodate the interests of livestock herders.
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