Taxonomic distinctness and species richness as measures of functional structure in bird assemblages

Most traditional "biodiversity" indices have an uncertain ecological interpretation, unfavourable sampling properties, and excessive data requirements. A new index of taxonomic distinctness (the average evolutionary distance between species in an assemblage) has many advantages over traditional measures, but its ecological interpretation remains unclear. We used published behavioural species data in conjunction with bird atlas data to quantify simple functional metrics (the fraction of species engaged in non-competitive interactions, and the average between-species disparity in habitat preferences) for breeding-bird assemblages in Europe and North America. We then analysed correlations of functional metrics with taxonomic distinctness and species richness, respectively. All functional metrics had weak, positive correlations with species richness. In contrast, correlations between functional metrics and taxonomic distinctness ranged from slightly negative to strongly positive, depending on the relative habitat heterogeneity, and on the resource involved in the between-species interaction. Strong positive correlations between taxonomic distinctness and the fraction of interactive species occurred for resources with few producer species per consumer species, and we suggest that taxonomic distinctness is consistently correlated with conservation worth. With its favourable sampling properties and data requirements, this taxonomic distinctness measure is a promising tool for biodiversity research and for environmental monitoring and management.     

Land‐use effects on the functional distinctness of arthropod communities

Land‐use change is a major driver of the global loss of biodiversity, but it is unclear to what extent this also results in a loss of ecological traits. Therefore, a better understanding of how land‐use change affects ecological traits is crucial for efforts to sustain functional diversity. To this end we tested whether higher species richness or taxonomic distinctness generally leads to increased functional distinctness and whether intensive land use leads to functionally more narrow arthropod communities. We compiled species composition and trait data for 350 species of terrestrial arthropods (Araneae, Carabidae and Heteroptera) in different land‐use types (forests, grasslands and arable fields) of low and high land‐use intensity. We calculated the average functional and taxonomic distinctness and the rarified trait richness for each community. These measures reflect the range of traits, taxonomic relatedness and number of traits that are observed in local communities. Average functional distinctness only increased significantly with species richness in Carabidae communities. Functional distinctness increased significantly with taxonomic distinctness in communities of all analyzed taxa suggesting a high functional redundancy of taxonomically closely related species. Araneae and Heteroptera communities had the expected lower functional distinctness at sites with higher land‐use intensity. More frequently disturbed land‐use types such as managed grasslands or arable fields were characterized by species with smaller body sizes and higher dispersal abilities and communities with lower functional distinctness or trait richness. Simple recommendations about the conservation of functional distinctness of arthropod communities in the face of future land‐use intensification and species loss are not possible. Our study shows that these relationships depend on the studied taxa and land‐use type. However, for some arthropod groups functional distinctness is threatened by intensification and conversion from less to more frequently disturbed land‐uses.     

Orb-weaving spider diversity in the Iberá Marshlands, Argentina

The Iberá Marshlands RAMSAR reserve, in the northeast of Argentina, is one of the largest and most important wetlands of America. In this study we assess orb-weaving spider (Araneae: Orbiculariae) diversity in this reserve, analyzing different facets of local diversity (species richness, diversity, evenness and taxonomic distinctness), and the contribution of species differentiation (beta diversity) among localities and habitat types to the composition of regional diversity. We found 1657 individuals of 59 orb-weaving spider species/morphospecies. Local diversity differs among the three sampled localities. At the habitat level, the different facets of biodiversity followed a clear pattern, where woodlands have higher species richness, diversity, evenness and taxonomic distinctness than savannas. Savanna sites shared a common spider species composition, while woodland communities have high values of complementarity. Thus, beta diversity has a very high contribution to the regional diversity of the orb-weaving spiders in the Iberá Marshlands. We suggest that conservation management in the reserve should be directed towards promoting natural spatial heterogeneity, giving special protection to habitat mosaics in different localities.     

Taxonomic distinctness and diversity of a hyperseasonal savanna in central Brazil

Savannas are characterized by a sharp seasonality, in which the water shortage defines the community functioning. Hyperseasonal savannas, however, experience additionally waterlogging in the rainy season. Since waterlogging may cause local extinctions of intolerant species, we asked whether waterlogging constricts the phylogenetic structure of a hyperseasonal savanna. We studied a hyperseasonal cerrado, comparing it with a nearby seasonal cerrado, never waterlogged, in Emas National Park, central Brazil. In each vegetation form, we sampled all vascular plants by placing fifty 1-m² quadrats in five surveys. We compared the phylogenetic structure of both vegetation forms, calculating their taxonomic distinctness, taxonomic diversity, expected taxonomic distinctness, and species, genus, and family similarities. The taxonomic distinctness of both cerrados was similar and the values of similarities were high, but taxonomic diversity and expected taxonomic distinctness were lower in the hyperseasonal cerrado than in the seasonal one. Assuming that phenotypic attraction is the major process organizing local communities, the waterlogging in hyperseasonal cerrado assembles phylogenetically unrelated species that have converged on similar habitat use. As a consequence, the habitat use of hyperseasonal cerrado species is a trait widespread in the phylogeny of seasonal cerrado. Waterlogging constrains the phylogenetic structure of the hyperseasonal cerrado, especially by reducing species diversity. In more ecological terms, we can only fully assess the phylogenetic structure of a community if we consider the species abundance.     

Effect of non-native species on taxonomic and functional diversity of fish communities in different river types

Recent researches suggest that functional diversity represents the response of communities to environmental alterations better than taxonomic diversity. However, there is scarce information about how the functional diversity of freshwater fishes is affected by habitat type and the dominance of non-native species. To address this question, we analysed a large database containing 15 morpho-functional traits of 61 fish species from the Pannon Biogeographic region (Hungary). Based on a fish faunistic list and relative abundance of taxa, we quantified the taxonomic and functional diversity of riverine communities for?>?700 sites of six habitat types. We asked how non-native fishes affected the taxonomic and functional diversity in different river types and at the local scale (i.e. at the site level), and how the diversity measures of native fauna elements changes along the invasion gradient. Our results showed that both functional and taxonomic richness increases with habitat complexity, from small headwater streams to large rivers. Therefore taxonomic diversity served as a good proxy for functional diversity along the environmental gradient of river types. Non-natives showed considerable functional diversity relative to their species number in each habitat type. Diversity values of native fauna elements initially increased, and then showed a major decrease along the invasion gradient. River type-specific evaluations highlighted the importance of considering the proliferation of invasive species based on both taxonomic and functional diversity indices. We argue that type-specific action plans are needed in conservation management to preserve the taxonomic and functional diversity of native fishes in Hungary, but also elsewhere.

     

Increasing variation in taxonomic distinctness reveals clusters of specialists in the deep sea

Changes in biodiversity with latitude or along a given environmental gradient have been described in many studies, including for marine ecosystems. Currently there is no scientific consensus, however, regarding macroecological patterns of diversity vs depth. Here, we describe variation in the biodiversity of fishes along a depth gradient from 0 to 2000 m in the region of the Norfolk Ridge and Lord Howe Rise (Western Pacific), using data obtained during the NORFANZ voyage. We modelled α diversity (richness), β diversity (using Jaccard's coefficient), evenness, taxonomic distinctness and taxonomic resemblances among fish communities. Although α diversity did not change appreciably with depth, β diversity decreased significantly in deeper strata. Both taxonomic resemblances and Jaccard similarities diminished with depth, indicating convergence in community structure. In addition, average taxonomic distinctness showed no clear pattern with depth, but taxonomic trees constructed among species within deeper samples had more variable path‐lengths than those in shallower samples. The presence of taxonomically distinct clusters of highly related species at depth indicates specialised niches that have developed in a relatively extreme (dark, pressurized) yet stable environment. We propose that reduced β diversity and increased variation in taxonomic distinctness might serve as indicators of ecological communities living in harsh environments – a hypothesis that should be tested in other systems, such as deserts, high altitudes or latitudes.     

Stochastic losses of fire‐dependent endemic herbs revealed by a 65‐year chronosequence of dispersal‐limited woody plant encroachment

The factors responsible for maintaining diverse groundcover plant communities of high conservation value in frequently burned wet pine savannas are poorly understood. While most management involves manipulating extrinsic factors important in maintaining species diversity (e.g., fire regimes), most ecological theory (e.g., niche theory and neutral theory) examines how traits exhibited by the species promote species coexistence. Furthermore, although many ecologists focus on processes that maintain local species diversity, conservation biologists have argued that other indices (e.g., phylogenetic diversity) are better for evaluating assemblages in terms of their conservation value. I used a null model that employed beta‐diversity calculations based on Raup–Crick distances to test for deterministic herbaceous species losses associated with a 65‐year chronosequence of woody species encroachment within each of three localities. I quantified conservation value of assemblages by measuring taxonomic distinctness, endemism, and floristic quality of plots with and without woody encroachment. Reductions in herb species richness per plot attributable to woody encroachment were largely stochastic, as indicated by a lack of change in the mean or variance in beta‐diversity caused by woody encroachment in the savannas studied here. Taxonomic distinctness, endemism, and floristic quality (when summed across all species) were all greater in areas that had not experienced woody encroachment. However, when corrected for local species richness, only average endemism and floristic quality of assemblages inclusive of herbs and woody plants were greater in areas that had not experienced woody encroachment, due to the more restricted ranges and habitat requirements of herbs. Results suggest that frequent fires maintain diverse assemblages of fire‐dependent herb species endemic to the region. The stochastic loss of plant species, irrespective of their taxonomic distinctness, to woody encroachment suggests that the relevance of niche partitioning or phylogenetic diversity to the management of biodiversity in wet pine savannas is minimal.     

Comparative assessment of indices of freshwater habitat conditions using different invertebrate taxon sets

Monitoring changes in population levels of a wide range of species in biodiversity research and conservation requires practical, easy-to-use and efficient assessment and monitoring methods. Dragonflies (Insecta: Odonata) are a valuable tool for assessing aquatic systems and have been used as indicators of ecological health, ecological integrity, and environmental change, including climatic change, as well as indicators of habitat recovery. We field-tested a freshwater ecological integrity index, the Dragonfly Biotic Index (DBI), based on dragonfly assemblages at the local scale, and compared the DBI to a biodiversity index (average taxonomic distinctness, AvTD) as well as to a standard freshwater benthic macroinvertebrate-based freshwater health index (South African Scoring System, using Average Score Per Taxon, ASPT). We sampled 20 river sites, selected a priori. Adult dragonflies and benthic macroinvertebrates were collected using standardized methods. Environmental variables were collected in situ, and water samples taken. Temperature and pH were the most important physical environmental variables in explaining the assemblage structure, and we found significant abiotic–biotic relationships, as well as biotic–biotic relationships. Overall, dragonflies were more sensitive to changes in river condition than were macroinvertebrates, in part because they were responding at the species rather than higher taxonomic level. AvTD scores did not show any significant relationship with changes in river condition. Furthermore, sites with low biotic scores (indicating disturbance) had high AvTD values. In contrast, DBI site value and ASPT scores were highly significantly correlated. We conclude that dragonfly assemblages in the form of a DBI are an excellent tool for environmental assessment and monitoring freshwater biodiversity, with the potential to replace labour-intensive benthic macroinvertebrate-based freshwater quality assessments, such as SASS.     

Patterns in freshwater diatom taxonomic distinctness along an eutrophication gradient

1. A variety of species richness measures have been used to assess the effects of environmental degradation on biodiversity. Such measures can be highly influenced by sample size, sampling effort, habitat type or complexity, however, and typically do not show monotonic responses to human impact. In addition to being independent of the degree of sampling effort involved in data acquisition, effective measures of biodiversity should reflect the degree of taxonomical relatedness among species within ecological assemblages and provide a basis for understanding observed diversity for a particular habitat type. Taxonomic diversity or distinctness indices emphasize the average taxonomic relatedness (i.e. degree of taxonomical closeness) between species in a community. 2. Eutrophication of freshwater ecosystems, mainly due to the increased availability of nutrients, notably phosphorus, has become a major environmental problem. Two measures of taxonomic distinctness (Average Taxonomic Distinctness and Variation in Taxonomic Distinctness) were applied to surface sediment diatoms from 45 lakes across the island of Ireland to examine whether taxonomic distinctness and nutrient enrichment were significantly related at a regional scale. The lakes span a range of concentrations of epilimnic total phosphorus (TP) and were grouped into six different types, based on depth and alkalinity levels, and three different categories according to trophic state (ultra‐oligotrophic and oligotrophic; mesotrophic; and eutrophic and hyper‐eutrophic). 3. The taxonomic distinctness measures revealed significant differences among lakes in the three different classes of trophic state, with nutrient‐rich lakes generally more taxonomically diverse than nutrient‐poor lakes. This implies that enrichment of oligotrophic lakes does not necessarily lead to a reduction in taxonomic diversity, at least as expressed by the indices used here. Furthermore, taxonomic distinctness was highly variable across the six different lake types regardless of nutrient level. 4. Results indicate that habitat availability and physical structure within the study lakes also exert a strong influence on the pattern of taxonomic diversity. Overall the results highlight problems with the use of taxonomic diversity measures for detecting impacts of freshwater eutrophication based on diatom assemblages.     

鄱阳湖鱼类多样性的时空变化特征研究

研究基于2010年4月、7月和2018年8月、2019年5月在鄱阳湖9个区域的鱼类多样性调查数据,分析鱼类物种多样性、功能多样性和分类差异指数的时空变化以及其与环境之间的关系,了解鄱阳湖近十年来鱼类群落多样性的时空变化特征。结果显示, 2010年和2018—2019年分别调查到鱼类74种和93种,群落结构差异显著(P<0.05),差异贡献率最高的物种为短颌鲚、似鳊、鲫、光泽黄颡鱼和鲤;水温、总悬浮物和叶绿素等环境因素具有显著的年际和季节差异(P<0.05)。与2010年相比, 2018—2019年鱼类物种多样性和功能多样性指数有一定增加,分类差异指数没有显著变化。分类差异指数的随机检验显示(Randomization test),与2010年相比, 2018—2019年位于95%概率置信范围下方的区域增加。水温、总悬浮物和叶绿素等环境因素对物种多样性、功能多样性和分类差异指数有显著的影响(P<0.05)。结果表明,近十年来,鄱阳湖鱼类群落结构发生明显改变,但是小型鱼类依旧是优势种,鱼类群落小型化明显,主要原因可能是过度捕捞的影响。同时,鄱阳湖的人类活动干扰增大,鄱阳县...     

Decline of Native Freshwater Fishes in a Mediterranean Watershed on the Iberian Peninsula: A Quantitative Assessment

We examined changes in the distribution of 9 native and 18 introduced freshwater fishes in the south-eastern Pyrenees watershed, Iberian Peninsula, using data from 1996, 1984–1988 and historical information. This region suffers many modifications to its freshwater ecosystems that are linked to human activity in the Mediterranean regions. Fish communities, stream physical habitat and environmental degradation were assessed at 168 sites from 11 basins in 1996. Seven native species (78%) showed decline from previous data, one of which became extirpated in the first half of the 20th century. On the other hand, introduced species are expanding. As a consequence, intact native communities are increasingly rare, declining from presence in 22% of river courses in 1984–1988 to 15% in 1996. The most typical community type is a mixture of native and introduced species occupying 30% of river courses. Stream degradation seems to be the main cause of this process because fish communities differed between degraded streams and streams suffering less impact. A principal component analysis showed that water pollution and modifications to the habitat were the two anthropogenic factors that accounted for most changes in the fish community integrity. Habitat alteration, primarily through construction of dams and water diversions, has fragmented habitats and isolated native fish communities in headwater streams. Current protection measures do not offer effective conservation of threatened species and communities. A global conservation and restoration programme from an ecosystem-based approach is essential to reverse the trend affecting native freshwater fishes in this Mediterranean region.     

Responses of taxonomic distinctness and species diversity indices to anthropogenic impacts and natural environmental gradients in stream macroinvertebrates

1. Many studies have shown traditional species diversity indices to perform poorly in discriminating anthropogenic influences on biodiversity. By contrast, in marine systems, taxonomic distinctness indices that take into account the taxonomic relatedness of species have been shown to discriminate anthropogenic effects. However, few studies have examined the performance of taxonomic distinctness indices in freshwater systems. 2. We studied the performance of four species diversity indices and four taxonomic distinctness indices for detecting anthropogenic effects on stream macroinvertebrate assemblages. Further, we examined the effects of catchment type and area, as well as two variables (pH and total phosphorus) potentially describing anthropogenic perturbation on biodiversity. 3. We found no indications of degraded biodiversity at the putatively disturbed sites. However, species density, rarefied species richness, Shannon's diversity and taxonomic diversity showed higher index values in streams draining mineral as opposed to peatland catchments. 4. Of the major environmental gradients analysed, biodiversity indices showed the strongest relationships with catchment area, lending further support to the importance of stream size for macroinvertebrate biodiversity. Some of the indices also showed weak linear and quadratic relationships to pH and total phosphorus, and residuals from the biodiversity index‐catchment area regressions (i.e. area effect standardized) were more weakly related to pH and total phosphorus than the original index values. 5. There are a number of reasons why the biodiversity indices did not respond to anthropogenic perturbation. First, some natural environmental gradients may mask the effects of perturbation on biodiversity. Secondly, perturbations of riverine ecosystems in our study area may not be strong enough to cause drastic changes in biodiversity. Thirdly, multiple anthropogenic stressors may either increase or decrease biodiversity, and thus the coarse division of sites into reference and altered streams may be an oversimplification. 6. Although neither species diversity nor taxonomic distinctness indices revealed anthropogenic degradation of macroinvertebrate assemblages in this study, the traditional species diversity and taxonomic distinctness indices were very weakly correlated. Therefore, we urge that biodiversity assessment and conservation planning should utilize a number of different indices, as they may provide complementary information about biotic assemblages.     

Habitat‐specific invertebrate responses to hydrological variability,anthropogenic flow alterations,and hydraulic conditions

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Comparative analysis of algal biodiversity in the rivers of Israel

Comparative analysis of algal communities in the rivers of Israel was completed to highlight the influence of environmental variables on biodiversity. The study revealed that 671 species of algae and cyanobacteria belonging to nine taxonomic divisions were present during 2002–2009 in the Yarqon, Alexander, Hadera, Qishon, Oren, Lower and Upper Jordan, and Zin rivers. The species richness of each river was evaluated by taxonomic structural comparison, geobotanical, hierarchical cluster analysis, and the degree of relatedness for different levels of taxonomic resolution. The analysis revealed close similarity of the Upper Jordan and Oren rivers. The average taxonomic distinctness index showed that the Yarqon, Oren, Upper Jordan, and Qishon communities were partly degraded due to permanent environmental disturbances. The variation in taxonomic distinctness index showed that the Alexander, Yarqon and Hadera communities were formed not only due to anthropogenic factors but also through long-term climatic impact. The most abundant indicator species inhabit low streaming and standing alkaline waters of medium salinity and low to medium organic pollution. The statistical approaches allowed discrimination between climatic and anthropogenic factors that impact upon the riverine biodiversity in semi-arid environments. Analysis shows the influence of anthropogenic factors was strongly modulated by climatic impacts causing a marked decease of species richness from north to south.     

Can taxonomic distinctness assess anthropogenic impacts in inland waters? A case study from a Mediterranean river basin

1. It is increasingly recognised that adequate measures of biodiversity should include information on the ‘relatedness’ of species within ecological assemblages, or the phylogenetic levels at which diversity is expressed. Taxonomic distinctness measures provide a series of indices to achieve this, which are independent of sample size. Taxonomic distinctness has been employed widely in marine systems, where it has been suggested that this index can provide a reliable measure of anthropogenic impact. 2. We tested the behaviour of three related taxonomic distinctiveness indices (Average Taxonomic Distinctness, Δ⁺; Variation in Taxonomic Distinctness, Λ⁺; and Total Taxonomic Distinctness, sΔ⁺) in relation to putative levels of anthropogenic impact in inland waters and their potential utility in environmental monitoring, using an extensive data set for aquatic beetles from the south‐east of the Iberian Peninsula. 3. Taxonomic distinctness measures were not able to identify human disturbance effects and there were no clear relationships between these new biodiversity measures and the disturbance level recorded at individual localities. Furthermore, the taxonomic distinctness measures used were apparently less sensitive to the effects of anthropogenic impact than other diversity metrics, such as species richness and rarity. 4. We conclude that taxonomic distinctness indices may not always perform as well as other metrics in the assessment of environmental quality. In addition, taxonomic distinctness measure should be interpreted with caution, as their performance and ability to detect anthropogenic disturbance may depend on the phylogenetic structure of sampled taxa within a region, and their evolutionary and ecological history.     

Catchments as conservation units for riverine biodiversity

The geological structure and longitudinal nature of river systems provide a possible barrier to the dispersal of lotic organisms. This has the potential to drive evolutionary processes such as genetic differentiation and subsequent allopatric speciation. In the conservation of lotic ecosystems population and evolutionary processes have largely been ignored. The traditional approach to river conservation has been focussed toward maintaining the physical habitat that provides the template for the biota. With a shift toward recognising the catchment as the primary operational unit for the conservation and management of lotic systems an examination of the biological relevance of these catchment units is required. This paper examines the structural influence of catchment units over population structure in lotic organisms and the extent to which catchments reflect populations and represent evolutionarily significant units. These being unique assemblages representing segments of biological diversity that share a common evolutionary lineage and contain the potential for a unique evolutionary future. This is of particular importance given the increased use of inter-basin water transfers to move water between historically isolated catchments and recognition of the catchment as the primary unit for the conservation and management of river ecosystems.     

Combined effects of immigration potential and habitat quality on diadromous fishes

In river systems, considerable debate exists as to why small-scale conservation with a primary focus on habitat quality brings little improvement to biological communities. To reveal potential causes of the enigmatic consequences, further explorations should focus on how species’ response to local environments is determined within a watershed. Here, we examined how immigration potential influences habitat associations of four diadromous fishes in the Shubuto River system in Hokkaido, Japan: sculpins (Cottus sp. ME and C. hangiongensis), gobies (Gymnogobius opperiens) and sea lamprey larvae (Lethenteron japonicum). We used closeness to the sea (i.e., distance from the sea) as a proxy for immigration potential, since the source of immigrants of the diadromous fishes is the river mouth. A multilevel modeling approach revealed that immigration potential had a “bottom-up effect” on local habitat–abundance relationships (current velocity and substrate coarseness), but habitat preferences did not vary along the gradient of immigration potential. This likely reflects the limited dispersal capabilities of the study species, whereby shorter travel distances may greatly enhance colonization success. Our study raises the possibility that the effectiveness of small-scale riverine conservation can be improved by selecting areas where successful colonization would be expected. Explicitly incorporating this consideration into conservation decision-making would help achieve greater success in environmental restoration and preservation actions.     

Taxonomic distinctness and aquatic Coleoptera: comparing a perennial and intermittent stream with differing geomorphologies in Hidalgo, Mexico

Taxonomic distinctness combines species richness and phylogenetic diversity to detect changes in taxonomic structure. Most studies have reported on changes due to marine impacts, with little emphasis on habitat influences or freshwater systems. The composition and organizational structure of aquatic Coleoptera assemblages are susceptible to local influence, yet their colonization capacities suggest greater assemblage similarity over larger spatial scales. Surveys were conducted in two contrasting local streams (approximately 20 km apart), one intermittent with multiple stair-step cascades and intervening pools during the rainy season (and only pools during the dry season), and the other perennial with low gradient, in Hidalgo, Mexico. Published information from these initial surveys and their associated collections of adults were examined and the data converted to monthly presence/absence data for analysis using taxonomic distinctness. Despite reported physicochemical differences between the streams, only the average monthly proportion of swimmer species was significantly higher in the intermittent stream where elmids and psephenids were largely missing due to the general absence of protective substrate and the presence of pools; higher taxonomic structure was not affected. Well-developed colonization capabilities and a widely distributed species pool likely reduced detectable differences between the stream assemblages. Although the average monthly value of Sorenson’s Similarity Index for aquatic Coleoptera between both streams was low, differentiation was not achieved using taxonomic distinctness and presence/absence data.     

Higher taxa vs. functional guilds vs. trophic groups as indicators of soil nematode diversity and community structure

Biodiversity surrogates are often used in ecology to save money and time. One such widely used surrogacy method is the higher taxon approach, also known in the literature as taxonomic sufficiency. This approach has rarely been applied to microscopic organisms like soil microfauna, although there is a lack of detailed taxonomic knowledge regarding the latter. We tested taxonomic sufficiency for genus alpha and beta diversity, as well as for community structure of soil nematodes. We also tested whether the functional classifications of nematodes into functional guilds and trophic groups can serve as efficient indicators of nematode diversity and community structure. We used data from soil nematode communities from five different microhabitats (soil, soil moss, rock moss, low tree trunk moss and high tree trunk moss) in forested and non forested areas at five different stations (differing in elevation and aspect). Our results showed that both the higher taxon approach and the functional surrogacy approach could serve as reliable indicators of alpha and beta diversity. Furthermore, our community analysis of both taxonomic and functional composition identified that the variability at the finer scales, and namely the habitat structure, played the leading role in shaping nematode communities.