COMPOSITION AND STRUCTURE OF THE TERMITE ASSEMBLAGE IN PRESERVED AND REGENERATING MIOMBO WOODLANDS OF SOUTHERN BURUNDI

COMPOSITION AND STRUCTURE OF THE TERMITE ASSEMBLAGE

IN PRESERVED AND REGENERATING MIOMBO WOODLANDS OF

SOUTHERN BURUNDI

Abstract

Miombo, those central, southern and eastern African woodlands dominated by three closely related genera from the legume family (Fabaceae, subfamily Caesalpinioideae: Brachystegia, Julbernardia and/or Isoberlinia) are under high anthropogenic pressure. Another conspicuous feature of miombo is the presence of high mounds built by fungus-growing termites.

Despite the extension and ecological importance of miombo woodlands, and the fundamental role of termites in African ecosystems, miombo termite communities remain very poorly known. Here, we carried out extensive sampling to determine the composition and structure of the termite assemblage in remnants of miombo woodlands in southern Burundi, as well as in an adjacent area formerly cleared for cultivation, but now regenerating.

From more than 1 000 samples collected from 56 termitaria and 396 matrix forest (5 m2 each) between the high mounds, we recorded a total of 25 termite species. Fungus-feeders, Macrotermitinae, Pseudacanthotermes spiniger, Odontotermes and Microtermes species were abundant everywhere. Besides scarce Coptotermes wood-feeders, Macrotermitinae were the sole inhabitants of the regenerating area.

In preserved miombo, the most remarkable feature of the assemblage was the high frequency and diversity of soldierless Apicotermitinae (13 species), usually regarded as humus-feeders, especially in the matrix between the termitaria. These mounds were home to inquiline or secondary soil-feeding termite species, seldom encountered outside those structures.

Our results emphasize the vulnerability of soil-feeding termites to habitat degradation, and the importance of high termitaria for particular species. Pending questions are to what extent

1 _{Manuscrit soumis pour publication le 30.11.2015:}

Nduwarugira D., Mpawenayo B., Roisin Y. – Composition and structure of the termite assemblage in preserved and regenerating miombo woodlands of southern Burundi – Insect Conservation and Diversity.

secondary occupants of termitaria directly depend on them for resources, and what are the precise feeding niches of soldierless Apicotermitinae. The miombo regenerating area constitutes an important opportunity to follow the process of its recolonisation by soil-feeding termites.

Résumé

Les forêts claires miombo sont des écosystèmes couvrant de vastes étendues en Afrique tropicale et subtropicale, mais elles sont menacées par une forte pression anthropique. Une des caractéristiques principales du miombo est la présence de hauts dômes érigés par les termites champignonnistes.

Malgré l'extension et l'importance écologique des forêts claires miombo, et le rôle crucial des termites dans les écosystèmes africains, les populations de termites du miombo restent très mal connues. Ici, nous avons réalisé un vaste échantillonnage pour déterminer la composition et la structure de l’assemblage de termites dans des fragments du miombo qui subsistent dans le sud du Burundi, ainsi que dans une zone adjacente précédemment défrichée et cultivée, mais actuellement en régénération.

À partir de plus de 1000 échantillons, nous avons recensé un total de 25 espèces de termites. Les Macrotermitinae (Pseudacanthotermes spiniger, Odontotermes et Microtermes) étaient abondants partout. À part de rares xylophages du genre Coptotermes, les Macrotermitinae étaient les seules espèces rencontrées dans la zone en régénération.

Dans le miombo moins perturbé, la caractéristique la plus importante de l'assemblage était la grande fréquence et la diversité (13 espèces) des termites sans soldats (Apicotermitinae), en particulier dans la matrice forestière entre les hautes termitières. Ces dernières abritaient plusieurs espèces de termites se nourrissant dans le sol, rarement observées en dehors de ces structures.

II.1. Introduction

Miombo woodlands cover about 2.7 million km2 in central, eastern and southern Africa (Campbell et al. 1996). They are considered a high-biodiversity wilderness, requiring special conservation efforts (Mittermeier et al. 2003). However, these ecosystems suffer from anthropogenic disturbance, including illegal encroachment, land use conversion, canopy reduction, etc. (Campbell et al. 1996). Although variations in the specific composition can be observed between areas (Campbell et al. 1996), these forests have a superior stratum constituted of Caesalpinioideae (Brachystegia, Isoberlinia and Julbernardia species) with an open canopy, a discontinuous understorey of shrubs and saplings (Eriosema, Sphenostylis, Kotschya, Dolichos, Indigofera, etc.) and a patchy layer of grasses (Hyparrhenia, Andropogon, Loudetia, Digitaria, etc.) or ferns (Frost 1996). A conspicuous feature of miombo woodlands is the presence of numerous high termitaria (Frost 1996), originally built by fungus-growing termites (Macrotermitinae). Due to their action on soils and its consequences on the whole biotic community, these termites are considered major ecosystem engineers (Lavelle et al. 1997, Jouquet et al. 2011). In many African savannas or woodlands, such termitaria induce heterogeneities playing an important structuring role on local biological communities (Pringle et al. 2010, Sileshi et al. 2010): they often support a distinctive vegetation (Konaté et al. 1999, Holdo & McDowell 2004), such as dense thickets (Moe et al. 2009), and provide food and habitat for a variety of mammals (Fleming & Loveridge 2003, Holdo and McDowell 2004), birds (Joseph et al. 2011), or arthropods (e.g., millipedes: Mwabvu 2005). In addition, large termitaria built by fungus-growers are almost invariably colonized by other termite species (Grassé 1984, Darlington 2012), and may therefore structure the local termite assemblage itself. The Afrotropical termite fauna is notable for the abundance and diversity of humus- or soil-feeders (Davies et al. 2003). Among these, Cubitermes species were shown to extract peptidic or other nitrogen-rich compounds from clay-humus complexes, digest them and release high amounts of NH3, thereby contributing to soil fertilization (Ngugi et al. 2011). Unfortunately, the actual sources of nutriments for other lineages of termites feeding within the humus or soil remain very poorly known.

extension and importance of miombo woodlands in eastern and southern Africa, very little is known of their local termite assemblages, except for a single study carried out on Nyika Plateau, Malawi, which revealed a moderate richness (27 species), marked by a high proportion of soldierless Apicotermitinae (17 species) (Donovan et al. 2002).

The Rumonge area in southwestern Burundi offers the opportunity to study miombo woodlands variously affected by human activities, and to follow the regeneration of miombo on parcels formerly cleared for agriculture.

In this study, we addressed the following questions: what is the natural richness and composition of the termite assemblage in miombo woodlands of southwestern Burundi ? Do large termitaria generate heterogeneities influencing termite diversity ? What are the properties of the termite assemblage in a young (~5 year-old) regenerating miombo ?

III.2. Materials and methods III.2.1. Study area

The study area covers two protected forests of the Rumonge-Vyanda Reserve in the locality of Rumonge in southwest Burundi.

(1) Nkayamba hill is situated north of the town of Rumonge, next to the RN3 road to Bujumbura. It occupies an elliptical area, approximately 1.9 km long by 1 km wide, bordered to the west by RN3, to the south by Rumonge suburbs, and to the east and north by oil palm plantations. The flora is marked by an arborescent stratum dominated by Brachystegia species, shrubby trees distributed throughout the forest, but at low density at higher elevations (e.g. Combretum sp., Pavetta crassipes, etc.). The herbaceous stratum is variable according to the extent of soil deterioration (Nzigidahera 2000). Due to its geographical situation, the Nkayamba hill has for a long time been used as a source of stones and gravel for the construction of various infrastructures in Rumonge and the region. Moreover, a large part of this ecosystem, covering approximately the eastern half of the hill, was completely cleared by local populations for agriculture during the Burundi crisis (1993–2008). However, since 2009, under the protection of INECN, cleared forest is regenerating spontaneously.

III.2.2. Sampling design and procedure

Sampling was conducted in May 2012, April-May 2013 and November-December 2013. Three sites were identified: Rumonge Forest Reserve (RuF), Nkayamba hill forest (NkF) and Nkayamba regenerating area (NkR). In each site, we set up three 60 m × 60 m grids (Table 3.S1), in which a sampling point was set every 10 m (= 49 sampling points per grid). GPS coordinates of each point were recorded, except for Grid #8 we met technical problems during sampling. At each sampling point, a quadrat of 5 m² (2.24 m × 2.24 m) was delimited and searched by one experienced collector for 30 minutes (protocol adapted from Jones & Eggleton 2000, modified by Roisin & Leponce 2004). Termites were searched for in dead wood, leaf litter, trees and foraging galleries up to a height of 2 m, under stones, and in the soil down to a depth of 10 cm. To avoid mound influence, sampling points falling on or next to large termite-built mounds were excluded, but the mounds themselves were extensively searched to collect all termite species present. Thereby, samples from termitaria versus samples from quadrats in the surrounding matrix between the mounds were distinguished. In total, 396 quadrats of 5 m² each were retained and 56 termitaria, all alive, searched. Samples were collected and preserved in 80% ethanol for identification in Belgium.

III.2.3. Data analysis

Samples of termites with soldiers were identified to the genus level according to the key of Bouillon & Mathot (1965). Identification was pursued to the species level whenever possible, otherwise samples were assigned to morphospecies. Several sources were used for species identification: Emerson (1960) for Furculitermes; Harris (1966) for Coptotermes; Williams (1966) for Cubitermes; and Sjöstedt (1926) for the remainder of the genera. Samples of workers without soldiers were sorted according to the general anatomy of the digestive tube (Sands 1998). Soldierright species were identified by comparison with samples containing all castes. Samples recognized as soldierless Apicotermitinae were identified according to Sands (1972, 1999) after dissection of the digestive tube, including the enteric valve. Soldierless Apicotermitinae morphospecies were initially given a sequential number, regardless of genus, and some of them were tentatively named. The presence of a species in a sampling unit (matrix quadrat or termitarium) was recorded as one occurrence, regardless of the number of individuals present or of the number of encounters with the species in the sampling unit.

and Simpson's (1/D, where D = ∑ pi2), where pi is the proportion of the individuals of species i in the sample. Rarefaction curves and diversity indices were calculated with EstimateS 9.1.0 (Colwell 2013).

We suspected the occurrence of non-random spatial patterns (aggregation) in the termite species distribution in grids and between sampling sites. For this reason, for each grid and sampling site, the spatial autocorrelation of the distribution of the common termite species (i.e. present in ≥ 10% of samples) was investigated using Moran’s I statistic with TOROCOR 1.0 (Hardy 2009). The same software was used to analyse the association between those common termite species taken pair by pair by calculating a Pearson’s correlation coefficient.

TOROCOR is designed (1) to test the spatial structure of quantitative or qualitative variables. The spatial autocorrelation of each variable is tested using complete randomizations, whereby the values of a variable are randomly shuffled among all samples. Moran’s I statistic, as well as the regression slopes associated, are recomputed for many randomized data sets to assess their distributions under the null hypothesis that there is no spatial structure; and (2) to test the significance of the association between variables by calculating Pearson’s correlation coefficients, notably using torus-translation randomizations. The goal of torus-translation randomizations is to break down the association between variables while keeping their respective spatial autocorrelation patterns intact, minimizing the risk of having false positives when applying tests of association. To avoid bias due to the spatial autocorrelation, significance of the observed values is established from their distributions obtained from 4999 torus-translations randomizations (i.e. 5000 randomizations or permutations minus the one corresponding to the rank of the observed value; p < 0.001) (Hardy 2009).

Grid #8 was not included in analyses because coordinates of individual sampling points were not available as justified above.

III.3. Results

III.3.1. Richness and composition of the termite assemblage

and paucity of rare species results in estimated values of total species richness only slightly higher than the observed richness (Table 3.2). Likewise, rarefaction curves level off to a very low slope, which also suggests that our sampling was complete, or nearly so (Fig. 3.1). On average, a 5-m² forest quadrat yielded 2.06 ± 0.37 termite species in Rumonge and 2.58 ± 0.81 species in Nkayamba, whereas the average number of species found on a termitarium was 5.94 ± 0.79 and 5.48 ± 1.54, respectively. The overall composition of the termite assemblage and diversity indices in Rumonge and Nkayamba forests were similar (Table 3.2). Four species were found exclusively in Rumonge and one exclusively in Nkayamba forest, but all were scarce, being represented only by 2–6 occurrences. Nine species were common, occurring in ≥ 10% of the matrix quadrats (Table 3.1). Seven of them (the three Macrotermitinae and four Apicotermitinae) reached this frequency level in both sites. The matrix fauna between the termitaria was highly dominated by soldierless Apicotermitinae, which constituted almost two-thirds of both the species richness (13/21) and the records (387/598 occurrences = 65% and 97.5% of the all soil feeder occurrences), followed by Macrotermitinae (191/398 occurrences = 32% of the records). Two species (Ateuchotermes sp. 04 and Alyscotermes sp. 07) were especially common in Nkayamba forest grids 3 and 4, while being scarce elsewhere (Fig. 3.2).

Fig. 3.2. Distribution of termite occurrences per taxonomic group in the different sites. RuF,

Table 3.1. Proportion (in %) of sampling units (termitaria or 5-m² quadrats of surrounding matrix) in which termite species occurred in miombo forests of Rumonge (RuF) and Nkayamba (NkF), and in regenerating vegetation (NkR) adjacent to Nkayamba forest. Ma: Matrix, Te: Termitarium).

Subfamily Species code Species RuF-Ma RuF-Te NkF-Ma NkF-Te NkR-Ma NkR-Te

Coptotermitinae Cop ama Coptotermes amanii – – – – 1.4 6.3

Cop sjo Coptotermes sjostedti 0.8 – 0.8 – 0.7 –

Macrotermitinae Pse spi Pseudacanthotermes spiniger 20.8 70.6 41.4 82.6 71.7 68.8

Odo A Odontotermes sp. A 23.8 58.8 24.2 56.5 25.4 50.0

Mic A Microtermes sp. A 12.3 58.8 25.8 69.6 58.7 43.8

Apicotermitinae Ada 01 Adaiphrotermes sp. 01 40.8 47.1 27.3 60.9 – –

Ade 02 Aderitotermes sp. 02 22.3 47.1 18.8 17.4 – –

Ach 03 Acholotermes sp. 03 chirotus 10.0 35.3 10.9 34.8 – –

Ate 04 Ateuchotermes sp. 04 3.8 11.8 39.1 43.5 – –

Ast 05 Astalotermes sp. 05 1.5 – 8.6 8.7 – –

Ast 06 Astalotermes sp. 06 0.8 – 1.6 – – –

Aly 07 Alyscotermes sp. 07 kilimandjaricus 1.5 11.8 26.6 13.0 – –

Ast 08 Astalotermes sp. 08 3.8 – 4.7 4.3 – –

Ach 09 Acholotermes sp. 09 6.2 – – 4.3 – –

Ane 10 Anenteotermes sp. 10 8.5 29.4 – 17.4 – –

Ast 11 Astalotermes sp. 11 36.2 41.2 23.4 21.7 – –

Ade 12 Aderitotermes sp. 12 2.3 17.6 – – – –

Ami 13 Amicotermes sp. 13 congoensis 1.5 5.9 – – – –

Cubitermitinae Cub pal Cubitermes pallidiceps – 23.5 – – – –

Fur soy Furculitermes soyeri 0.8 52.9 0.8 43.5 – –

Bas aur Basidentitermes aurivillii 3.8 17.6 0.8 4.3 – –

Termitinae Ter hos Termes hospes – – 1.6 8.7 – –

Pro pyg Promirotermes pygmaeus – 17.6 – 13.0 – –

Mcc ede Microcerotermes edentatus – 11.8 – – – –

Mcc par Microcerotermes parvus 4.6 35.3 1.6 43.5 – –

Average occurrences / unit 2.06 5.94 2.58 5.48 1.58 1.69

Sampling units (quadrats - mounds) 130 17 128 23 138 16

Table 3.2. Observed and estimated (Chao2) species richness and diversity statistics for the three

sites (RuF, NkF, NkR), distinguishing termitaria (-Te) from surrounding matrix (-Ma).

Site RuF-Ma RuF-Te NkF-Ma NkF-Te NkR-Ma NkR-Te

Samples 130 17 128 23 138 16 Occurrences 268 101 330 126 218 27 Species observed 20 18 17 18 5 4 Uniques 3 1 3 3 1 1 Duplicates 3 3 3 2 1 0 Chao2 20.74 18.00 17.74 18.96 5.00 4.00 Fisher's α 5.00 6.37 3.80 5.75 0.91 1.30 Shannon's eH 11.34 15.14 10.79 13.14 2.97 3.31 Simpson's 1/D 8.66 13.51 9.40 11.09 2.70 3.10

III.3.2. Termite fauna of termitaria

Fig. 3.3. Relationship between occurrence of species in forest matrix quadrats versus termitaria

(in percent of sampling units occupied, Rumonge and Nkayamba forests combined). Orange, Coptotermitinae; red, Macrotermitinae; blue, Apicotermitinae; black, Cubitermitinae; green, Termitinae. Species codes as in Table 3.1.

III.3.3. Termite fauna of the regenerating area

III.3.4. Spatial distribution and associations of species

The analysis of spatial distributions showed few consistent patterns. Only in Grid #5 was the distribution of most species aggregated, suggesting habitat heterogeneity (Table 3.S4). Apart from Odontotermes sp. A and Aderitotermes sp. 02, all common species show a patchy distribution within grids or between sites (Table 3.S5).

Species associations were very scarce. Even if an association seemed to exist, it looked too weak. Indeed, there was a negative correlation between Adaiphrotermes sp. 01 and

Odontotermes sp. A (r = -0.32, p ˂ 0.05) in Grid #1. In Grid #7, a negative correlation was noticed between Aderitotermes sp. 02 and Astalotermes sp. 11 (r = -0.36, p ˂ 0.05) and a positive one between Adaiphrotermes sp. 01 and Odontotermes sp. A (r = 0.32, p ˂ 0.05). No correlation was observed between species in Grid #6. A positive correlation was observed between Acholotermes sp.03 and Microcerotermes parvus in Grid #3 (r = 0.33, p ˂ 0.05) and a negative one between Aderitotermes sp. 02 and Ateuchotermes sp. 04 (r = -0.54, p ˂ 0.05), in Grid #4. No species association was noted in Grid #5.

In general, no significant association (at p < 0.01) between species was found, with the single exception of a negative association between Pseudacanthotermes spiniger and Odontotermes sp. A (r = -0.37, p < 0.01) only detected in Grid #9 (Table 3.3).

Table 3.3. Number of (positive or negative) associations between the occurrences of termite

species collected tested pair by pair for positive or negative association, for each sampling grid (Pearson’s correlation calculated after 4999 toroidal randomizations).

Site Grid # Number of positive

III.4. Discussion

III.4.1. Richness and composition of the termite assemblage

The 25 clearly distinguishable morphospecies probably represent near-completely the local assemblage, although we cannot exclude that some morphospecies actually include two or more sibling species. In a Sudanian savanna in Benin, mitochondrial DNA sequencing suggested that four sibling species of Microtermes and two of Odontotermes occur in sympatry (Hausberger et al. 2011). A definitive species richness assessment would thus require the use of molecular tools. However, our data can be compared with previous studies similarly based on morphospecies recognition. With 25 recognized termite species, the miombo of southern Burundi displays a moderate richness, similar to that observed by Donovan et al. (2002) in upland (1680–1900m a.s.l.) Brachystegia woodlands in northern Malawi (27 species in two 200-m² transects). Such values are much below those obtained from afrotropical rain forests, such as Mbalmayo Forest Reserve, Cameroon, where two 200-m² transects in near-primary and old secondary forests yielded 73 species (Eggleton et al. 1995), or Mayombe Biosphere Reserve, Congo, where the same area of rainforest provided 79 species (Eggleton et al. 2002b), values which in neither case were likely to approach the actual total richness. Comparative data from other African ecosystems are scarce, but our richness estimate for southern Burundi miombo falls within the range of estimates for African savannas (Ferrar 1982a, Dosso et al. 2010).

diversity (13/24 species = 54%) and abundance (387/598 occurrences = 65% in the matrix; 94/227 = 41% on termitaria) of soldierless Apicotermitinae in both forested sites. In the matrix alone, soldierless Apicotermitinae constituted 97.5% of the soil feeder occurrences. High diversity and abundance of soldierless Apicotermitinae were also observed in miombo woodlands in Malawi, where they represented 17/27 species (63%) and 74/117 encounters (63%) in the two areas of Brachystegia forests sampled (Donovan et al. 2002). These figures are higher than in any other habitat studied to date (review in Bourguignon et al. 2016), suggesting a natural association between miombo woodlands and soldierless Apicotermitinae. In the neotropics, species of this lineage feed on a broad spectrum of substrates, covering the complete range of the humification gradient from decayed wood to organic-poor soil (Bourguignon et al. 2009 2015). Unfortunately, very little is known of the actual diet of afrotropical species. Stable isotope data suggest that two Astalotermes from Cameroon rainforests feed on less humified matter than the larger Cubitermitinae (Tayasu et al. 1997). Miombo soils are poor in nutrients and organic matter; the dominant Caesalpinioideae are ectomycorrhizal and do not fix atmospheric nitrogen, which suggests that the ecosystem is mainly limited by phosphorous availability (Högberg 1986, Frost 1996). Large mound-building Macrotermitinae collect a substantial part of the litter, which is brought to the termitaria where it nourishes the fungus combs. As a result, mounds are much richer in nutrients than the surrounding matrix (Sileshi et al. 2010, Joseph et al. 2013). The reasons for the remarkable abundance and diversity of soldierless Apicotermitinae we observed in the matrix remain to be investigated, and in particular, their relationships with ectomycorrhizal fungi omnipresent in the environment.

III.4.2. Termite fauna of termitaria

humification, into humic acids and organo-mineral complexes (Ji & Brune 2005). Other Cubitermitinae (Furculitermes and Basidentitermes) probably feed in the same fashion. Promirotermes is catalogued as a humus feeder (Ferrar 1982b), although little is known about its actual feeding habits. Another benefit of termitaria is that they retain moisture, thereby providing buffered environmental conditions for secondary occupants during the dry season. Finally, an existing nest structure provides protection against predators at a low cost for non-builders. Although Darlington (2012) favors the last two hypotheses, we suggest that the concentration of nutrients in the termitaria, the modification of the soil structure and the generally favourable conditions create opportunities for soil feeders. The key question to be answered is whether secondary inhabitants feed within the termitaria or rather use it as a base to forage in the surrounding matrix.

III.4.3. Termite fauna of the regenerating forest

Apart from scarce occurrences of Coptotermes sjostedti and C. amanii in dead wood, only Macrotermitinae were found in the regenerating forest, where the three species were abundant. The presence of Pseudacanthotermes spiniger, Odontotermes and Microtermes species could be expected as these taxa are common in disturbed areas, including agricultural zones where they are notorious pests (Rouland-Lefèvre 2011). A low frequency of soil feeders was also expected, because this guild is the most affected by anthropogenic disturbance (Wood et al. 1982, Eggleton et al. 1996, 2002). Here, after several years of cultivation and 4-5 years of fallow, soil feeders were completely absent from the regenerating area. Likewise, in Côte d'Ivoire, Dosso et al. (2013) observed the total absence of soil-feeding termites in an area submitted to two years of cultivation followed by four years of fallow, while some species were still present, at low frequencies, in mixed crop fields and tree plantations. Forest clearance followed by cultivation and fallow thus appears fatal to soil-feeding termites, but the location of the Nkayamba regeneration area, adjacent to the preserved Nkayamba forest, provides an unique opportunity to follow the recolonisation of the habitat by soil-feeding termites along with forest regeneration over long periods of time.

III.4.4. Spatial distribution and associations of species

in preserved forests, common species show, to a variable extent, differences in their spatial distribution among grids, within or between sites. This is especially obvious for soldierless species Acholotermes sp. 03, Ateuchotermes sp. 04, Alyscotermes sp. 07 and Astalotermes sp. 11. This suggests that one key to soldierless species diversity might be their adaptation to different edaphic conditions, whereas another key might be their specialization at different levels in the humification gradient (Bourguignon et al. 2009). Patchy distribution for species could also reflect food quality or some other aspects of food acquisition in an area (Wilson & Clark 1977). More detailed studies on the distribution and the diet are particularly needed for soil-feeding species to elucidate the reasons for their specific richness in the poor soil of miombo.

Co-occurrence data at the local (quadrat) scale were almost universally non-significant. This may indicate that species do not defend exclusive foraging areas against each other, a behaviour which seems unlikely for soil dwellers. The absence of significance of co-occurrences between termite species in our study area may not mean they do not defend foraging territories. Indeed, colony mosaics, the behavioural mechanisms of territoriality and the ecological consequences of exclusive use of foraging space in termites may be analogous to those found in ants (Adams & Levings 1987). Even if only a few species of termites have been studied to date, this assertion appears to be correct (Traniello & Leuthold 2000). Understanding territoriality in termites requires a good deal of additional studies, but aggressive interactions have been described in the field in some termite species (Traniello & Leuthold 2000) (e.g., three arboreal-nesting and wood-feeding termite species: Leponce et al. 1997). Future researches are necessary to elucidate the species relationships in our study area given that territories in termites are highly dynamic (Traniello & Leuthold 2000) and the temporal scale was not studied. Furthermore, the disappearance of soil-feeding termites in regenerating miombo might be due to the loss of their natural trophic association with non-soil-feeding termites when the area was deforested and cultivated. Indeed, non-soil-feeding termites may produce organic-rich faeces that can act as a food resource for the soil-feeding termites (Donovan et al. 2007). According to these authors, deforestation can break this putative trophic relationship, and this could have implications for ecosystem functioning, and may delay or inhibit ecosystem recovery.

III.5. Conclusions and perspectives

feeders seldom encountered in the matrix. Whether these species concentrate their activity within the termitarium or leave it to forage remains to be investigated. As to the regenerating, 5 year-old miombo, its termite fauna almost exclusively consists of fungus growers. Whereas the dietary habits of Cubitermes-group soil feeders have been documented, and those of wood feeders are evident, those of soldierless Apicotermitinae remain largely unknown. Elucidating the feeding niches of this abundant and diversified lineage, and its role in ecosystem functioning, is a major challenge for future studies. In addition, the Nkayamba setting provides a chance to follow the evolution of the termite fauna, and in particular, the recolonisation by soil dwellers, in a regenerating miombo for the coming decades.

Acknowledgements

We thank the authorities of the Institut National pour l’Environnement et la Conservation de la Nature (INECN, Burundi) for allowing us to conduct research in their nature reserve, and particularly for the cooperation of their agents in Rumonge. This work was supported by the Government of Burundi, the Office of International Relations and Cooperation of ULB and grants from the Fonds David et Alice Van Buuren and the Fonds Meurs-François (ULB).

III.6. References

AANEN, D. K. & EGGLETON, P. 2005: Fungus-growing termites originated in African rain forest. Current Biology 15: 851–855.

ACKERMAN, I. L., CONSTANTINO, R., GAUCH, H. G .J., LEHMANN, J., RIHA, S. J. & FERNANDES, E. C. M. 2009: Termite (Insecta: Isoptera) species composition in a primary rain forest and agroforests in Central Amazonia. Biotropica 41: 226–233. ADAMS, E. A. & LEVINGS, S. C. 1987: Territory size and population limits in mangrove

termites. Journal of Animal Ecology 56: 1069–1081.

AHMED(SHIDAY), B. M., NKUNIKA, P. O. Y., SILESHI, G. W., FRENCH, J. R. J., NYEKO, P. & JAIN, S. 2011: Potential impact of climate change on termite distribution in Africa. British Journal of Environment and Climate Change 1(4):

172–189.

BAPTISTA, S. L., PINTO, P. V., FREITAS, M. C., CRUZ, C. & PALMEIRIM, J. M. 2012: Geophagy by African ungulates: the case of the critically endangered giant sable antelope of Angola (Hippotragus niger variani). African Journal of Ecology 51: 139– 146.

BIGNELL, D. E. & EGGLETON, P. 2000: Termites in ecosystems. Termites: Evolution, Sociality, Symbioses, Ecology. In T. Abe (eds.), D.E. Bignell & M. Higashi (eds.). Dordrecht, Kluwer Academic Publishers: 363–387.

BOUILLON, A. & MATHOT, G. 1965: Quel est ce termite africain? Zooleo 1: 1–115.

BOURGUIGNON, T., ŠOBOTNÍK, J., LEPOINT, G., MARTIN, J.-M. & ROISIN, Y. 2009: Niche differentiation among neotropical soldierless soil-feeding termites revealed by stable isotope ratios. Soil Biology & Biochemistry 41: 2038–2043.

BOURGUIGNON, T., DROUET, T., ŠOBOTNÍK, J., HANUS, R. & ROISIN, Y. 2015: Influence of soil properties on soldierless termite distribution. PLoS ONE 10: e0135341. BOURGUIGNON, T., ŠOBOTNÍK, J., DAHLSJÖ, C.A.L. & ROISIN, Y. 2016: The

soldierless Apicotermitinae: insights into a poorly known and ecologically dominant tropical taxon. Insectes Sociaux, doi: 10.1007/s00040-015-0446-y.

CAMPBELL, B., FROST, P. & BYRON, N. 1996: Miombo woodlands and their use:

Overview and key issues. In B. Campbell (eds.), The Miombo in Transition: Woodlands and Welfare in Africa. Bogor, Center for International Forestry Research: 1–10.

COLWELL, R. K. 2013: EstimateS, version 9.1.0. University of Connecticut, online at http://viceroy.eeb.uconn.edu/estimates/index.html

DARLINGTON, J. P. E. C. 2012: Termites (Isoptera) as secondary occupants in mounds of Macrotermes michaelseni (Sjöstedt) in Kenya. Insectes Sociaux 59: 159–165.

DARLINGTON, J. P. E. C., BENSON, R. B., COOK, C. E. & WALKER, G. 2008:

Resolving relationships in some African fungus-growing termites (Termitidae, Macrotermitinae) using molecular phylogeny, morphology, and field parameters. Insectes Sociaux 55: 256–265.

DAVIES, R. G., EGGLETON, P., JONES, D. T., GATHORNE-HARDY, F. J. &

HERNÁNDEZ, L. M. 2003: Evolution of termite functional diversity: analysis and synthesis of local ecological and regional influences on local species richness. Journal of Biogeography 30: 847–877.

DONOVAN, S. E., GRIFFITHS, G. J. K., HOMATHEVI, R. & WINDER, L. 2007: The spatial pattern of soil-dwelling termites in primary and logged forest in Sabah, Malaysia. Ecological Entomology 32: 1–10.

DOSSO, K., KONATÉ, S., AIDARA, D. & LINSENMAIR, K. E. 2010: Termite diversity and abundance across fire-induced habitat variability in a tropical moist savanna (Lamto, central Côte d'Ivoire). Journal of Tropical Ecology 26: 323–334.

DOSSO, K., DELIGNE, J., YÉO, K., KONATÉ, S. & LINSENMAIR, K. E. 2013: Changes in the termite assemblage across a sequence of land-use systems in the rural area around Lamto Reserve in central Côte d'Ivoire. Journal of Insect Conservation 17: 1047–1057. EGGLETON, P., BIGNELL, D. E., SANDS, W. A., WAITE, B., WOOD, T. G. &

LAWTON, J. H. 1995: The species richness of termites (Isoptera) under differing levels of forest disturbance in the Mbalmayo Forest Reserve, southern Cameroon. Journal of Tropical Ecology 11: 85–98.

EGGLETON, P., BIGNELL, D.E., SANDS, W.A., MAWDSLEY, N.A., LAWTON, J.H., WOOD, T.G. & BIGNELL, N.C. 1996: The diversity, abundance and biomass of termites under differing levels of disturbance in the Mbalmayo Forest Reserve, southern Cameroon. Transactions of the Royal Society of London, Series B 351: 51–68.

EGGLETON, P., BIGNELL, D.E., HAUSER, S., DIBOG, L., NORGROVE, L. &

MADONG, B. 2002a: Termite diversity across an anthropogenic disturbance gradient in the humid forest zone of West Africa. Agriculture, Ecosystems & Environment 90: 189–202.

EGGLETON, P., DAVIES, R.G., CONNÉTABLE, S., BIGNELL, D.E. & ROULAND, C. 2002b: The termites of the Mayombe Forest Reserve, Congo (Brazzaville): transect sampling reveals an extremely high diversity of ground-nesting soil feeders. Journal of Natural History 36: 1239–1246.

EMERSON, A. E. 1960: Six new genera of Termitinae from the Belgian Congo (Isoptera, Termitidae). American Museum Novitates 1988: 1–49.

ERENS, H., BOUDIN, M., MEES, F, MUJINYA, B. B., BAERT, G., VAN STRYDONCK, M., BOECKX, P. & VAN RANST, E. 2015b: The age of large termite mounds— radiocarbon dating of Macrotermes falciger mounds of the Miombo woodland of Katanga, DR Congo. Palaeogeography, Palaeoclimatology, Palaeoecology 435: 265– 271.

South African National Scientifc Programmes Report No. 60. C.S.I.R., Pretoria, Republic of South Africa.

FERRAR, P. 1982b: Termites of a South African savanna. I. List of species and subhabitat preferences. Oecologia 52: 125–132.

FLEMING, P. A. & LOVERIDGE, J. P. 2003: Miombo woodland termite mounds: resource islands for small vertebrates ? Journal of Zoology 259: 161–168.

FROST, P. 1996: The ecology of miombo woodlands. In B. Campbell (eds.), The Miombo in Transition: Woodlands and Welfare in Africa. Center for International Forestry Research, Bogor: 11–56.

GRASSÉ, P.-P. 1984: Termitologia. Anatomie - Physiologie - Biologie - Systématique des Termites. Tome II. Fondation des Sociétés - Construction. Masson, Paris.

HAKIZIMANA, P. 2012: Analyse de la composition, de la structure spatiale et des ressources végétales naturelles prélevées dans la forêt dense de Kigwena et dans la forêt claire de Rumonge au Burundi. PhD thesis, Université Libre de Bruxelles.

HARDY, O. 2009: TOROCOR: a program to assess the association between spatially

autocorrelated variables using a torus-translation test on multiple grids. http://ebe.ulb.ac.be/ebe/Software.html.

HARRIS, W.V. 1966: On the genus Coptotermes in Africa (Isoptera: Rhinotermitidae). Proceedings of the Royal Entomological Society of London.Series B.Taxonomy) 35: 161–171.

HAUSBERGER, B., KIMPEL, D., Van NEER, A. & KORB, J. 2011: Uncovering cryptic species diversity of a termite community in a West African savanna. Molecular Phylogenetics and Evolution 61: 964–969.

HOLDO, R. M. & McDOWELL, L. R. (2004): Termite mounds as nutrient-rich food patches for elephants. Biotropica 36 231–239.

HÖGBERG, P. 1986: Soil nutrient availability, root symbioses and tree species composition in tropical Africa. A review. Journal of Tropical Ecology 2: 359–372.

JI, R. & BRUNE, A. 2005: Digestion of peptidic residues in humic substances by an alkali stable and humic-acid-tolerant proteolytic activity in the gut of soil-feeding termites. Soil Biology & Biochemistry 37: 1648–1655.

JONES, D. T. & EGGLETON, P. 2000: Sampling termite assemblages in tropical forests: testing a rapid biodiversity assessment protocol. Journal of Applied Ecology 37: 191–203.

EGGLETON, P. 2003: Termite assemblage collapse along a land-use intensification gradient in lowland central Sumatra, Indonesia. Journal of Applied Ecology 40:

380–391.

JOSEPH, G. S., CUMMING, G. S., CUMMING, D. H. M., MAHLANGU, Z., ALTWEGG, R. & SEYMOUR, C. L. 2011: Large termitaria act as refugia for tall trees, deadwood and cavity-using birds in a miombo woodland. Landscape Ecology 26: 439–448. JOSEPH, G.S., SEYMOUR, C.L., CUMMING, G.S., CUMMING, D.H.M. & MAHLANGU,

Z. 2013: Termite mounds as islands: woody plant assemblages relative to termitarium size and soil properties. Journal of Vegetation Science 24: 702–711.

JOUQUET, P., BOTTINELLI, N., LATA, J. C., MORA, P. & CAQUINEAU, S. 2007: Role of the fungus-growing termite Pseudacanthotermes spiniger (Isoptera, Macrotermitinae) in the dynamic of clay and soil organic matter content. An experimental analysis. Geoderma 139: 127–133.

JOUQUET, P., TRAORÉ, S., CHOOSAI, C., HARTMANN, C. & BIGNELL, D. 2011: Influence of termites on ecosystem functioning. Ecosystem services provided by termites. European Journal of Soil Biology 47: 215–222.

KONATÉ, S., LE ROUX, X., TESSIER, D. & LEPAGE, M. 1999: Influence of large

termitaria on soil characteristics, soil water regime, and tree leaf shedding pattern in a West African savanna. Plant and Soil 206: 47–60.

LAVELLE, P., BIGNELL, D. E., LEPAGE, M., WOLTERS, V., ROGER, P., INESON, P., HEAL, O. W. & DHILLION, S. 1997: Soil function in a changing world: the role of invertebrate ecosystem engineers. European Journal of Soil Biology 33: 159–193. LEPONCE, M., ROISIN, Y. & PASTEELS, J. M. 1997: Structure and dynamics of the

arboreal termite community in New Guinean coconut plantations. Biotropica 29: 193–203.

MAGURRAN, A. E. 2004: Measuring Biological Diversity. Blackwell Science, Malden, MA. MALAISSE, F. 1985: Comparison of the woody structure in a regressive Zambezian

succession, with emphasis on high termitaria vegetation (Luiswishi, Shaba, Zaïre). Bulletin de la Société Royale de Botanique de Belgique / Bulletin van de KoninklijkeBelgische Botanische Vereniging 118(2): 244–265.

MITTERMEIER, R. A., MITTERMEIER, C. G., BROOKS, T. M., PILGRIM ,J. D.,

MOE, S. R., MOBÆK, R. & NARMO, A. K. 2009: Mound building termites contribute to savanna vegetation heterogeneity. Plant Ecology 202: 31–40.

MUJINYA, B. B., MEES, F., BOECKX, P., BODÉ, S., BAERT, G., ERENSA, H.,

DELEFORTRIE, S., VERDOODT, A., NGONGO, M. & VAN RANST, E. 2011:The

origin of carbonates in termite mounds of the Lubumbashi area, D.R. Congo. Geoderma 165: 95–105.

MWABVU, T. 2005: The density and distribution of millipedes on termite mounds in miombo woodland, Zimbabwe. African Journal of Ecology 43: 400–402.

NGUGI, D. K., JI, R. & BRUNE, A. 2011: Nitrogen mineralization, denitrification, and nitrate ammonification by soil-feeding termites: a 15N-based approach. Biogeochemistry 103: 355–369.

NZIGIDAHERA, B. 2000: Analyse de la diversité biologique végétale nationale et identification des priorités pour sa conservation. INECN, Bujumbura.

OKWAKOL, M. J. N. 2000: Changes in termite (Isoptera) communities due to the clearance and cultivation of tropical forest in Uganda. African Journal of Ecology 38: 1–7. PRINGLE, R. M., DOAK, D. F., BRODY, A. K., JOCQUÉ, R. & PALMER, T. M. 2010:

Spatial pattern enhances ecosystem functioning in an African savanna. PLoS ONE 8: e1000377.

ROISIN, Y. & LEPONCE, M. 2004: Characterizing termite assemblages in fragmented forests: A test case in the Argentinian Chaco. Austral Ecology 29: 637–646.

ROULAND-LEFÈVRE, C. 2011: Termites as pests of agriculture. In D. E. Bignell, Y. Roisin & N. Lo (eds.), Biology of Termites: A Modern Synthesis. Dordrecht, Springer SBM: 499–517

SANDS, W. A. 1972: The soldierless termites of Africa (Isoptera: Termitidae). Bulletin of the British Museum (Natural History) Entomology Supplement 18: 1–244.

SANDS, W. A. 1998: The Identification of Worker Castes of Termite Genera From Soils of Africa and the Middle East. CAB International, Wallingford.

SANDS, W. A. 1999: A review of the soldierless African termite genus Amicotermes Sands 1972 (Isoptera, Termitidae, Apicotermitinae). Bulletin of the Natural History Museum, London (Entomology) 68: 145–193.

SILESHI, G. W., ARSHAD, M. A., KONATÉ, S. & NKUNIKA, P. O. Y. 2010: Termite- induced heterogeneity in African savanna vegetation: mechanisms and patterns. Journal of Vegetation Science 21: 923–937.

Vetenskapsakademiens Händlingar (ser. 3) 3(1): 1–419.

TAYASU, I., ABE, T., EGGLETON, P. & BIGNELL, D. E. 1997: Nitrogen and carbon isotope ratios in termites: an indicator of trophic habit along the gradient from wood-feeding to soil-wood-feeding. Ecological Entomology 22: 343–351.

TRANIELLO, J. F. A. & LEUTHOLD, R. H. 2000:Behavior and ecology of foraging in termites. Termites: Evolution, Sociality, Symbioses, Ecology. In T. Abe, D.E. Bignell & M. Higashi (eds.). Dordrecht, Kluwer Academic Publishers: 141–168.

WATSON, J. P. 1967: A Termite mound in an iron age burial ground in Rhodesia. Journal of Ecology 55(3): 663–669.

WILLIAMS, R. M. C. 1966: The East African termites of the genus Cubitermes (Isoptera: Termitidae). Transactions of the Royal Entomological Society, London 118: 73–118. WILSON, D. S. & CLARK, A. B. 1977: Above ground predator defense in the harvester

termite, Hodotermes mossambicus (Hagen). Journal of the Entomological Society of South Africa 40: 271–282.

Supplementary information

Table 3.S1. List of sampled sites and grids (coordinates of central point).

Site and Grid # Latitude S Longitude E Date

Rumonge forest (RuF)

Table 3.S2. Absolute number of occurrences of termite species in matrix quadrats (per grid, and total values per site). One occurrence = presence

of one species in one sampling unit. Empty cell = 0. RuF, Rumonge forest; NkF, Nkayamba forest; NkR, Nkayamba regenerating area.

Table 3.S3. Absolute number of occurrences of termite species in termitaria (per grid, and total values per site). One occurrence = presence of

one species in one sampling unit. Empty cell = 0. RuF, Rumonge forest; NkF, Nkayamba forest; NkR, Nkayamba regenerating area.

Table 3.S4. Slope coefficients linked to Moran’s I test after spatial autocorrelation analysis

using complete randomization (4 999 replicates) of frequent species (present in > 10% of the matrix quadrats) occurrences within grids; Ho: no spatial autocorrelation (= random distribution) (*** for p < 0.001; ** for p < 0.01; * for p < 0.05). G1–G10: grids. Species codes as in Table 1.

Rumonge forest Nkayamba forest Nkayamba

regenerating area Species G1 G6 G7 G3 G4 G5 G9 G10 Pse_spi 0.063 0.039 0.035 -0.097 0.024 -0.009 * -0.035 -0.114* Odo_A -0.059 0.038 -0.007 0.016 -0.016 -0.215 ** -0.028 0.038 Mic_A -0.053 -0.013 -0.009 -0.004 -0.064 -0.049 * 0.063 -0.047 Ada_01 -0.075 -0.147* -0.008 -0.052 0.041 -0.245 *** Ade_02 0.011 -0.033 0.025 -0.085 -0.001 -0.338 *** Ach_03 -0.163* -0.011 -0.069 -0.378 *** Ate_04 -0.034 -0.118* 0.037 0.097*** Aly_07 -0.031 -0.111* 0.052 0.037 Ast_11 0.019 -0.058 0.001 -0.068 0.035 0.034

Table 3.S5. Slope coefficients linked to Moran’s I test after spatial autocorrelation analysis

using complete randomization (4 999 replicates) of frequent species (present in > 10% of the matrix quadrats) occurrences within sites; Ho: no spatial autocorrelation (= random distribution) (*** for p < 0.001; ** for p < 0.01; * for p < 0.05). RuF, Rumonge forest; NkF, Nkayamba forest; NkR, Nkayamba regenerating area. Species codes as in Table 1.

Sites

Species RuF NkF RuF + NkF NkR RuF+NkF +NkR

Amicotermes sp. 13

Fig. 3.S1. Structure of the enteric valves for the 13 Apicotermitae species sampled in miombo