Change in termite communities along a chronosequence of mango tree orchards in the north of Côte d’Ivoire

Termites constitute the major component of the macrofauna of the soil, and influence the structure of the soil, in tropical regions. This study aimed to estimate their assemblages in a chronosequence of mango tree orchards in the north of Côte d’Ivoire and compare them with those in unmanaged savanna. Using a standardized method of rapid biodiversity estimation, termites were collected in seven age classes of mango tree orchards (class 1: <5 years; class 2: 5–9 years; class 3: 10–14 years; class 4: 15–19 years; class 5: 20–24 years; class 6: 25–29 years; class 7: 30 years and over) and compared with termites collected from the savanna. Results show that the species richness was lowest in the young orchards of class 1 (9 species), and increased with the age of the orchards to reach its maximum in the old orchards of class 7 (28 species); these latter were comparable in richness with the savanna (26 species). The Shannon index (H’) and the evenness (E) follow the same trend as the species richness. The orchards of classes 1 and 2 were more dissimilar to the savanna. In contrast, termites were well represented in the savanna and in the old orchard of classes 6 and 7. Rhinotermitinae and Cubitermitinae subfamilies, absent in the young orchards of classes 1 and 2, were very abundant in the old orchards (classes 6 and 7). Overall, the findings of this study show that only the old mango orchards sustain termite diversity that comes close to that of the savanna. In this region, the cessation of agricultural activities in mango orchards favors the reconstitution of termite communities and presumably the restoration of the ecosystem services provided by termites. Thus it would be possible to combine agriculture and the conservation soil biodiversity.     

Is livestock grazing compatible with biodiversity conservation? Impacts on savanna ant communities in the Australian seasonal tropics

Grazing by domestic livestock is one of the most widespread forms of anthropogenic disturbance globally, and can have a major impact on biodiversity and therefore conservation values. Here we use ants to assess the extent to which livestock grazing is compatible with biodiversity conservation in a tropical savanna of northern Australia, where there is growing pressure to intensify pastoral production. We focus on the extent to which ant responses conform with four general patterns identified in a recent global review: (1) soil and vegetation type have a far bigger impact on ant community composition than does grazing; (2) grazing modifies ant species composition but often not species richness or total abundance; (3) a species’ response often varies among habitats; and (4) between 25–50% of the species that can be statistically analysed are responsive to grazing. We sampled ants using pitfall traps at 38 sites in two land systems, based on cross-fence comparisons of areas of different grazing intensities. A total of 130 ant species from 24 genera were recorded, with the fauna dominated by species of Iridomyrmex and Monomorium. Land system was the primary driver of variation in ant species richness and composition, and grazing intensity was related to neither species richness nor total abundance. Only 10% of common species appeared to be impacted by grazing. Overall, ant responses to grazing in our study region were generally consistent with the four global patterns, except that the local fauna seems to be particularly resilient. Such resilience indicates that current grazing management practices are compatible with the conservation of ant biodiversity.     

Strong positive effects of termites on savanna bird abundance and diversity are amplified by large herbivore exclusion

Vast areas of the African savanna landscapes are characterized by tree‐covered Macrotermes termite mounds embedded within a relatively open savanna matrix. In concert with termites, large herbivores are important determinants of savanna woody vegetation cover. The relative cover of woody species has considerable effects on savanna function. Despite the potentially important ecological relationships between termite mounds, woody plants, large herbivores, and birds, these associations have previously received surprisingly little attention. We experimentally studied the effects of termites and large herbivores on the avian community in Lake Mburo National Park, Uganda, where woody vegetation is essentially limited to termite mounds. Our experiment comprised of four treatments in nine replicates; unfenced termite mounds, fenced mounds (excluding large mammals), unfenced adjacent savanna, and fenced savanna. We recorded species identity, abundance, and behavior of all birds observed on these plots over a two‐month period, from late dry until wet season. Birds used termite mounds almost exclusively, with only 3.5% of observations occurring in the treeless intermound savanna matrix. Mean abundance and species richness of birds doubled on fenced (large herbivores excluded) compared to unfenced mounds. Feeding behavior increased when large mammals were excluded from mounds, both in absolute number of observed individuals, and relative to other behaviors. This study documents the fundamental positive impact of Macrotermes termites on bird abundance and diversity in an African savanna. Birds play crucial functional roles in savanna ecosystems, for example, by dispersing fruits or regulating herbivorous insect populations. Thus, the role of birds in savanna dynamics depends on the distribution and abundance of termite mounds.     

Disturbance‐modulated symbioses in termitophily

Symbiosis, the living‐together of unlike organisms, underlies every major transition in evolution and pervades most ecological dynamics. Among examples of symbioses, the simultaneous occupation of a termite nest by its builder termites and intruding invertebrate species (so‐called termitophily) provides suitable macroscopic scenarios for the study of species coexistence in confined environments. Current evidence on termitophily abounds for dynamics occurring at the interindividual level within the termitarium, but is insufficient for broader scales such as the community and the landscape. Here, we inspect the effects of abiotic disturbance on termitophile presence and function in termitaria at these broader scales. To do so, we censused the termitophile communities inhabiting 30 termitaria of distinct volumes which had been exposed to increasing degrees of fire‐induced disturbance in a savanna‐like ecosystem in southeastern Brazil. We provide evidence that such an abiotic disturbance can ease the living‐together of termitophiles and termites. Putative processes facilitating these symbioses, however, varied according to the invader. For nonsocial invaders, disturbance seemed to boost coexistence with termites via the habitat amelioration that termitaria provided under wildfire, as suggested by the positive correlation between disturbance degree and termitophile abundance and richness. As for social invaders (ants), disturbance seemed to enhance associational defenses with termites, as suggested by the negative correlation between the presence of ant colonies and the richness and abundance of other termitarium‐cohabiting termitophiles. It is then apparent that disturbance‐modulated distinct symbioses in these termite nests.     

Termite Mounds Increase Functional Diversity of Woody Plants in African Savannas

Fine-scale spatial heterogeneity influences biodiversity and ecosystem productivity at many scales. In savanna systems, Macrotermes termites, through forming spatially explicit mounds with unique woody plant assemblages, emerge as important sources of such heterogeneity. Despite a growing consensus regarding the importance of functional diversity (FD) to ecosystem processes, no study has quantified how termite mounds affect woody plant FD. We address whether termite mounds alter the distribution of functional traits, and increase FD of woody plant communities within Africa’s largest savanna woodland, the 2.7 million km² miombo system. Using plant traits that change according to soil resources (for example, water and nutrients), and disturbance (for example, fire and elephant herbivory), we identified response functional groups and compared relative representation of these groups between mound and matrix habitats. We also asked whether mound and matrix habitats differed in their contribution to FD within the system. Although species representing most functional groups were found in both mound and matrix habitats, relative abundance of functional groups differed between mound and matrix. Mound plant assemblages had greater response diversity to soil resources than matrix plots, but there was no difference in response diversity to disturbance. High trait values on mounds included tree height, leaf nitrogen, phosphorus, and palatability. Species with root ectomycorrhizae dominated the matrix. In conclusion, these small patches of nutrient-enriched substrate emerge as drivers of FD in above-ground woody plant communities.     

Termites facilitate and ungulates limit savanna tree regeneration

Both large herbivores and termites are key functional groups in savanna ecosystems, and in many savanna areas, large termite mounds (termitaria) are associated with distinct woody clusters. Studies on the effect of large mammals on tree regeneration are few, and the results are conflicting. Large herbivores have been found to be important seedling predators in some areas, but facilitate tree regeneration by outcompeting small mammals and reducing grass cover in other areas. Through the use of the experimental fencing of termite mounds and adjacent savanna areas in this study, we investigated how termites and large herbivores influence tree regeneration. Termite mounds had a higher number of seedlings, more species richness, more alpha diversity (OD) and lower evenness (E) than savanna plots. Large herbivores did not significantly affect overall seedling density, species richness, OD or E. Beta diversity was higher in savanna areas than on termitaria, and beta diversity decreased in savanna areas when herbivores were excluded. Herbivore exclusion increased the density of the 12 (40 %) most common seedling species, representing 79 % of all seedlings, and fenced plots had relatively taller seedlings than open plots. Thus, termites were the main determinants of tree regeneration in our study area, but large mammals regulated the most common species. Although our study confirms previous work suggesting that large herbivores affect tree regeneration, we found that termites were an even more important determinant. Termite impacts on tree regeneration deserve increased attention by savanna ecologists.     

Invasive ants as back-seat drivers of native ant diversity decline in New Caledonia

Biological invasions are typically associated with disturbance, which often makes their impact on biodiversity unclear—biodiversity decline might be driven by disturbance, with the invader just being a ‘passenger’. Alternatively, an invader may act as a ‘back-seat driver’, being facilitated by disturbance that has already caused some biodiversity decline, but then causing further decline. Here we examine the interactive effects of anthropogenic fire and invasive ant species (Anoplolepis gracilipes or Wasmannia auropunctata) on native ant diversity in New Caledonia, a globally recognized biodiversity hotspot. We first examined native ant diversity at nine paired burnt and unburnt sites, with four pairs invaded by Anoplolepis, 5 years after an extensive fire. In the absence of invasion, native epigaeic ants were resilient to fire, but native ant richness and the abundance of Forest Opportunists were markedly lower in invaded burnt sites. Second, we examined native ant diversity along successional gradients from human-derived savanna to natural rainforest in the long-term absence of fire, where there was a disconnection between disturbance-mediated variation in microhabitat and the abundance of the disturbance specialist Wasmannia. All native ant diversity responses (total abundance, richness, species composition, functional group richness and the abundance of Forest Opportunists) declined independently of microhabitat variables but in direct association with high Wasmannia abundance. Our results indicate that invasive ants are acting as back-seat drivers of biodiversity decline in New Caledonia, with invasion facilitated by disturbance but then causing further biodiversity decline.     

Changes in the termite assemblage across a sequence of land-use systems in the rural area around Lamto Reserve in central Côte d’Ivoire

Termites are major decomposers in tropical regions and play an important role in soil processes. This study investigated the termite assemblage structure across a sequence of differing land-use systems. With a standardized method, data were collected on termites from the following habitats: semi-deciduous forest, teak plantation, cocoa plantation, Jatropha plantation, food crop field and 4-years old fallow. Termite species richness declined from the semi-deciduous forest to 4-years old fallow through teak plantation, food crop field, cocoa plantation and Jatropha plantation. The relative abundance of fungus-growers was the highest in all land-use types while that of soil-feeders steeply declined in all man-modified sites. The wood-feeding species showed clear responses to disturbance, with low abundances in monospecific- and modified sites without high trees. Comparisons with other studies suggest that changes in the termite assemblage structure result from forest conversion to agricultural systems. To help mitigate the loss of termites when forests are disturbed or cleared, we recommend to: (1) promote the association of cropping and silvicultural systems that reduces changes in microclimate and maintains the original termite assemblage with the associated ecosystem services; (2) leave dead wood on the ground after forest disturbance to accelerate the recovery of the termite assemblage; and (3) increase forest and silvicultural patch size and reduce length of forest edges to sustain the survival of forest-dependent species.     

Seasonal changes in activity of subterranean termite species (Isoptera) in Western Australian wheatbelt habitats

Subterranean termite assemblages in woodland, mallee and heath habitats of the Western Australian wheatbelt were sampled for seasonal changes in species richness and species abundance. The study was carried out in Durokoppin and Kodj Kodjin Nature Reserves between January and November 1988, and a trench method was used to sample termites. Species richness changed over time, with monthy means of: woodland 10 species (range: 5–15), mallee 8 species (range: 4–15), heath 8 species (range: 5–15). Species richness was highest in autumn and spring when termite activity in the soil was also highest due to favourable soil moisture. Amitermes neogermanus and Tumulitermes petilus were the most abundant species in woodland and mallee in all seasons. During summer, the pooled observations of these two species accounted for 50% (woodland) and 82% (mallee) of all observations. Their predominance may be due to greater tolerance of low soil moisture and a more diverse diet than obligate wood-feeders (e.g. Rhinotermitidae). The latter were generally absent near the soil surface in summer, possibly because food sources deeper within the soil were utilized. Four species were abundant in heath: Tumulitermes dalbiensis (monthly mean 20% of all species observations), T. comatus (13%), Amitermes. sp.‘R’ (18%)and Drepanotermes rubriceps (12%). These four species showed no seasonal change in their relative abundance, possibly because their diet restricted them to surface-foraging.     

放牧干扰下高寒草甸物种多样性指数评价与选择

在青藏高原东北缘高寒草甸设置6个放牧强度样地,连续4年研究10个多样性指数(Richness和Abundance 2个实测指数,优势度指数、均匀度指数、丰富度指数和综合指数各2个)对放牧强度和年限影响植物群落的解释能力.结果表明: 相对于重要值,利用多度计算的多样性指数对放牧干扰更敏感.优势度指数(Berger-Parker、Dominance)与放牧强度和年限均无关,不能将放牧干扰对群落优势种的影响有效区分.均匀度指数(Equitability、Evenness)均与放牧强度无关,但Evenness指数与放牧年限呈显著负相关,不受偶见种影响且与物种多度的变异系数呈显著正相关,在基于时间尺度的均匀度比较中可以选择Evenness指数.丰富度指数(Menhinick、Margalef)均与放牧年限无关,但Margalef指数与放牧强度呈显著正相关,且不受偶见种影响.综合指数(Shannon、Simpson)均与放牧强度无关,但Shannon指数与物种丰富度和多度呈显著正相关,且随放牧年限增加而显著升高,不受偶见种影响,Shannon指数可用于在长时间尺度下比较物种多样性变化.在所有多样性指数中,只有实测物种丰富度和多度均与放牧强度呈显著负相关,与放牧年限呈显著正相关,且不受偶见种影响,故实测物种丰富度和多度相结合可作为放牧干扰下多样性比较的首选指标.此外,多样性指数选择须考虑放牧干扰的强度与时间特征、多样性组分和研究目的.     

Infestation of African savanna ecosystems by subterranean termites

This review is an analysis of the dimensions of termite infestation in African savannas. The aim of this work is to draw the attention of ecologists, conservationists, policy makers and farmers to the current and future threats of subterranean termites to the functioning and sustainability of such ecosystem habitats. This study analyzes and describes termite problem (questionable changes in density and assemblage structure) in selected African savannah ecosystems, synthesizes information on the effects of various human induced habitat disturbance regimes on termites’ assemblage structure, predators, nests and feed resources to generate hypotheses relating termite infestation with anthropogenic activities; it describes and critiques existing termite management practices. The review is suggestive that the infestation and resultant undesirable effects of subterranean termites in African savannahs are largely a consequence of the inappropriate savannah management practices (overgrazing, indiscriminate tree cutting and overhunting) undertaken by humans in pursuit of various livelihood options. Based on the evidence presented herein, we hypothesized that (1) human induced habitat disturbance in savanna ecosystems alters the feeding group composition of termites’ assemblages, favoring grass harvesters and polyphagus termite feeders that forage on more abundant food items, paying little attention to rarer food items and (2) habitat disturbance through activities like heavy grazing and overhunting results in decline in the populations of both macro and microscopic termite predators, which eventually enhances the proliferation of termite populations, escalates the density of termite nests particularly epigeal mounds and intensifies consumption of herbaceous savannah vegetation. The review calls for dedicated efforts to develop ecological thresholds of savannah biotic and abiotic ecosystem components in which human induced disturbance regimes trigger the destructive behavior of termites. This would provide information that will act as a precautionary savannah habitat monitoring and decision support tool to prevent future infestation of savannah habitats with termites. Also, the review shows that majority of the termite control practices are ineffective, ecologically unsustainable and above all, do not address the root cause of termite infestation and thus merely provide temporary relief to the problem. As such, termite control methods that attempt to enhance proliferation of termite predators need to be studied, developed and emphasized. This review reveals that human induced habitat disturbance depletes termites’ predator populations, leading to proliferation of termite populations particularly grass harvesters that intensify their consumption on grass biomass and eventually contribute to denudation of herbaceous vegetation cover in savannah ecosystems.     

Latitudinal Variation in Termite Species Richness and Abundance along the Brazilian Atlantic Forest Hotspot

In this study, we investigated the termites of the Brazilian Atlantic Forest, one of the most threatened biodiversity hotspots in the world, in regularly spaced sites from 7° S to 27° S latitude. To our knowledge, this is the only report of a latitudinal survey of termites at species level performed with a standardized sampling protocol. We evaluate termite diversity and abundance, and describe patterns of species composition based on feeding groups along the latitudinal gradient. We also describe the relative contribution of environmental variables to explain diversity patterns. Termite assemblages were investigated by standardized surveys at 15 Atlantic Forest sites, on six transects divided into five sections of 10 m², with 30 sections per site (or 300 m²/site), which were investigated by one trained person for one hour. Observed species richness and abundance were negatively correlated with latitude. The influence of latitude was explained mainly by variables related to temperature, precipitation and ambient energy (potential evapotranspiration). Our results also suggest that temperature exerts a greater constraint on Atlantic Forest termites than productivity, because ambient productivity increases with latitude in this forest but termite diversity decreases. Termite species richness in the Atlantic Forest showed a different pattern than those described for other organisms, increasing in diversity where the coastal‐forest strip narrows. Overall, our results indicate comparatively high termite species richness at northeastern sites and a significant impoverishment of termite assemblages in the southeastern and southern regions of the Atlantic Forest.     

Impacts of clearing,fragmentation and disturbance on the bird fauna of Eucalypt savanna woodlands in central Queensland,Australia

Abstract This study reports on the responses of bird assemblages to woodland clearance, fragmentation and habitat disturbance in central Queensland Australia, a region exposed to very high rates of vegetation clearance over the last two to three decades. Many previous studies of clearing impacts have considered situations where there is a very sharp management contrast between uncleared lands and cleared areas: in this situation, the contrast is more muted, because both cleared lands and uncleared savanna woodlands are exposed to cattle grazing, invasion by the exotic grass Cenchrus ciliaris and similar fire management. Bird species richness (at the scale of a 1‐ha quadrat) was least in cleared areas (8.1 species), then regrowth areas (14.6 species), then uncleared woodlands (19.9 species). Richness at this scale was unrelated to woodland fragment size, connectivity or habitat condition; but declined significantly with increasing abundance of miners (interspecifically aggressive colonial honeyeaters). At whole of patch scale, richness increased with fragment size and decreased with abundance of miners. This study demonstrates complex responses of individual bird species to a regional management cocktail of disturbance elements. Of 71 individual bird species modelled for woodland fragment sites, the quadrat‐level abundance of 40 species was significantly related to at least one variable representing environmental position (across a rainfall gradient), fragment condition, fragment size and/or connectivity. This study suggests that priorities for conservation management include: cessation of broad‐scale clearing; increased protection for regrowth (particularly where this may bolster connectivity and/or size of woodland fragments); control of miners; maintenance of fallen woody debris in woodlands; increase in fire frequency; and reduction in the incidence of grazing and exotic pasture grass.     

The effects of tree clearing and pasture establishment on a population of mound-building termites (Isoptera) in North Queensland

Populations of mound-building termites were examined in a semi-arid tropical woodland and in an adjacent area cleared of trees and sown with Urochloa mosambicensis 14 years previously. In that period both the density and diversity of the mound-building termite populations were reduced in the cleared area. Only two of the six mound-building species found in the undisturbed woodland recolonized the pasture. These species, Amitermes vitiosus and Nasutitermes longipennis, both detritus feeders, are able to survive on the Urochloa leaf material and cattle dung. The absence of the harvester species Tumulitermes pastinator, Drepanotermes perniger and Drepanotermes rubriceps from the Urochloa pasture is attributed to the lack of acceptable food resources.     

The Impact of Anthropogenic Disturbance on Assembly Patterns of Termite Communities

Intensification of land‐use threatens biodiversity, especially in tropical ecosystems that harbor the planet's highest species richness. This negative impact of anthropogenic disturbance on species numbers is well established, but the mechanisms underlying the community assembly processes are less well understood. Termites are of fundamental importance in tropical ecosystems where they are critical for nutrient recycling and species diversity. We tested the impact of anthropogenic disturbance on termite species diversity and assembly processes in a West African savanna applying the newest techniques of phylogenetic community analyses. Species richness dropped in areas of intensive land‐use and compositional similarity between intensive land‐use areas was high. This contrasted with a protected National Park where communities were characterized by high species richness and intermediate species turnover between sites. Slightly disturbed areas in the buffer zone surrounding the park were intermediate, they still had high species richness but similarity between sites increased. Strikingly, the assembly pattern also changed with disturbance from more phylogenetic overdispersion to more clustering (coexisting species became phylogenetically more similar), but only when the fungus‐growing termite Macrotermes bellicosus was absent. Our data suggest that the major forces structuring termite communities depend: (1) on the presence of this dominant mound‐building termite; and (2) that they change to more environmental filtering with disturbance. Anthropogenic disturbance seems to function as a filter that allows only a specific subset of species to occur. Such an effect might be widespread in ecology but it is difficult to document quantitatively. Phylogenetic community analyses can help to contribute such evidence.     

Traditional management of forests: plant and bird community responses to alternative restoration of oak–hazel woodland in Sweden

Species richness of vascular plants and birds were examined in relation to five types of management (including abandonment) of oak-hazel woodland in south-central Sweden. The biodiversity of this type of woodland is affected by lengthy management in contrast to present emphasis on the fragmentation of more or less pristine forests. The woodlands derive from old deciduous forests but were a source of agricultural commodities from medieval time to end of the 19th century. Vascular plants and birds were censused during spring–summer for four years. Total number of plant species, species of field layer forbs, breeding birds and migrant birds were more numerous at simulated original management with mowing of small interior grasslands than at mechanical clearing or abandonment. Summer grazing led to intermediate numbers. Exotic plants were more common at long-time abandonment. Species richness of trees and shrubs, graminoids, all spring birds, resident birds and non-passerine birds did not exhibit any difference between treatments. Inter-site variation in species richness was usually smaller at abandonment than at true management. Species richness of plants and birds showed positive correlation in the particularly large sites examined. The general findings were in accordance with the intermediate disturbance hypothesis. Original management would secure most potential plant and bird species but extensive cattle grazing would also retain many species.     

Ecological context of savanna chimpanzee (Pan troglodytes verus) termite fishing at Fongoli, Senegal

Chimpanzees (Pan troglodytes verus) at Fongoli, Senegal, consume termites year-round. Understanding the ecological context behind this behavior is especially important in light of the environmental conditions at Fongoli. This mosaic savanna habitat is one of the hottest and driest sites where chimpanzees have been studied. Two genera and four species of termites were found in association with tools used by chimpanzees in a sample of 124 termite mounds that were monitored. The chimpanzees of Fongoli termite fish predominantly in woodland and forest habitat types, and, although woodland accounts for the majority of the chimpanzees' home range, forest habitat types comprise only about 4% of their range. Thus, habitat type has an influence on the Fongoli chimpanzees' termite fishing. Termite consumption to the degree seen at Fongoli may have particular significance for hominid evolution, given the expansion of Pliocene hominids into increasingly open, hot, and dry habitats.     

Development of secondary woodland in oak wood pastures reduces the richness of rare epiphytic lichens

Wooded pastures with ancient trees were formerly abundant throughout Europe, but during the last century, grazing has largely been abandoned often resulting in dense forests. Ancient trees constitute habitat for many declining and threatened species, but the effects of secondary woodland on the biodiversity associated with these trees are largely unknown. We tested for difference in species richness, occurrence, and abundance of a set of nationally and regionally red-listed epiphytic lichens between ancient oaks located in secondary woodland and ancient oaks located in open conditions. We refined the test of the effect of secondary woodland by also including other explanatory variables. Species occurrence and abundance were modelled jointly using overdispersed zero-inflated Poisson models. The richness of the red-listed lichens on ancient oaks in secondary woodland was half of that compared with oaks growing in open conditions. The species-level analyses revealed that this was mainly the result of lower occupancy of two of the study species. The tree-level abundance of one species was also lower in secondary woodland. Potential explanations for this pattern are that the study lichens are adapted to desiccating conditions enhancing their population persistence by low competition or that open, windy conditions enhance their colonisation rate. This means that the development of secondary woodland is a threat to red-listed epiphytic lichens. We therefore suggest that woody vegetation is cleared and grazing resumed in abandoned oak pastures. Importantly, this will also benefit the vitality of the oaks.     

Mound building termites contribute to savanna vegetation heterogeneity

With biomass densities comparable to large ungulates and megaherbivores, termites play a key functional role in many tropical savanna ecosystems. This study focuses on vegetated termite mounds (termitaria) constructed by the Termitidae species Macrotermes herus. We studied how resource rich termitaria affect graminoid herbs (Poaceae and Cyperaceae), forbs and woody species composition and diversity. The density of termitaria explained 89% of the variation in dense thickets in the area. Fire tolerant Acacia species dominated the open savanna while fire sensitive species like Grewia spp. and the succulent Euphorbia candelabrum were restricted to termite mounds. Termitaria plots had four times the mean number of woody species and supported three times as many forb species as the adjacent savanna. For woody species, both the Shannon–Wiener index and the Shannon evenness index were higher on temitaria than on the savanna. There were no differences for graminoid herbs, except for the Shannon evenness index which was higher on termitaria. Our results indicate that graminoid herb richness peaks at lower productivity levels than trees and forbs in savanna ecosystems, as also recently found in temperate areas.     

Termite diversity in Neotropical dry forests of Colombia and the potential role of rainfall in structuring termite diversity

Termites are ecosystem engineers that play an important role in the biotransformation and re‐distribution of nutrients in soil. The dry forests are endemic repositories, but at same time, they are most threatened by extensive livestock and crop farming, fires, and climate change. In Colombia, the best‐protected dry forests are located in the north. The termite fauna of dry forests are poorly known. The aim was to identify the termite species occurring in tropical dry forests of the Colombian Caribbean coast in relation to diet and precipitation, temperature, elevation, and soil properties. A total of 32 species in 1,103 occurrences were found. Termitidae accounted for 78% of the species richness with the Anoplotermes‐group, Microcerotermes, and Nasutitermes being the dominant genera. Differences in species composition and abundance were found across sites. These differences may be linked to anthropogenic disturbance and polygyny and polydomy. Strikingly, our highest elevation site (334 m) had the highest species richness much higher than the two lower elevation sites. This implies an inversion of the common elevation‐diversity gradient, also found for termites which can be explained by increasing precipitation with elevation in the dry forest. An analysis of termite species richness at the global scale confirms that termite species richness correlates positively with rainfall. Hence, rainfall seems to positively affect termite diversity. In line, the studied Colombian tropical dry forests had low diversity compared to rain forests. A decline of species‐rich soil‐feeding termites with increasing aridity may explain why the highest termite diversity occurs in humid tropical rain forests. Abstract in Spanish is available with online material.