Ecological Axes Research Articles

Identifying the Key Protection Areas of Alpine Marsh Wetlands in the Qinghai Qilian Mountains, China: An Ecosystem Patterns–Characteristics–Functions Combined Method

The alpine marsh wetlands in the Qilian Mountains of Qinghai (QMQ) are under constant threat from the effects of climate change and human activities. Identifying the key ecological protection areas (KEPAs) of marsh wetlands is the prerequisite for formulating protection strategies and executing spatial planning programs. The current study developed a novel method to identify the KEPAs of marsh wetlands by following the ecosystem pattern–characteristics–functions (EPCFs) combined method and the ecological source–ecological corridor–ecological node research paradigm. More specifically, an evaluation system for ecological resistance was constructed by integrating the drivers of EPCFs in the marsh wetlands. Additionally, the marsh wetland degradation disturbances were analyzed through the drivers of EPCFs incorporated with a field survey. The findings indicated the following: (1) The marsh wetlands had a total water yield of approximately 3.96 × 108 m3. The soil conservation rate and habitat quality per unit area were calculated to be 52.92 t·hm−2·a−1 and 0.992, respectively, with higher values observed on the southern bank and lower values on the northern bank of the river in the QMQ. (2) The KEPAs for the marsh wetlands covered a total extent of 996.53 km2 in the QMQ, encompassing 40 ecological sources, 39 ecological corridors, and 40 ecological nodes, predominantly located in the river source regions. (3) The KEPAs were restructured into an ecological framework comprising two ecological axes, four ecological belts, four ecological cores, and multiple nodes in the QMQ. In response to the factors contributing to the degradation of marsh wetlands, adaptive measures including prioritizing natural restoration, modifying grazing strategies, executing ecological restoration projects as a minimum, and designating protected areas have been recommended. This research could contribute to enhancing the efficiency of regional territorial planning and offer a theoretical foundation for improving the ecological protection framework of regional marsh wetlands.

A Tale of Two Lakes: Divergent Evolutionary Trajectories of Two Daphnia Populations Experiencing Distinct Environments.

Most studies of local adaptation substitute the correlation between spatial distance and environmental heterogeneity for the temporal dynamics over which local adaptation evolves. The availability of detailed ecological and genomic information from lake sediments provides an opportunity to study local adaptation with unparalleled clarity from the temporal perspective. Inference can be further enhanced by including multiple lakes along ecological axes to further isolate the effects of ecological change in driving local adaptation. Lakes throughout the world face the impact of numerous anthropogenically induced environmental changes. Top among these is the eutrophication of freshwaters from agriculture, development, and land-use change. Here, we use the genetic information recorded in lake sediments of two lakes experiencing contrasting histories of land-use change to study the evolution of local adaptation in the lakes' Daphnia pulicaria populations. Utilizing nextRAD derived single-nucleotide polymorphisms (SNPs) in resurrected clonal lineages, we studied the evolutionary trajectories of Daphnia pulicaria in both lakes. Using gene-environment correlations and F st tests for selection, we found SNPs that appear to be under selection in both lakes. Specifically, we found more outlier SNPs in the highly impacted lake using F st-based tests for selection. Conversely, gene-environment tests revealed the reverse pattern. We discuss numerous facets of experimental design that must be considered when using resurrection ecology to study local adaptation and critically evaluate how they may have impacted the of this investigation.

Testing the radiation cascade in postglacial radiations of whitefish and their parasites: founder events and host ecology drive parasite evolution.

Reciprocal effects of adaptive radiations on the evolution of interspecific interactions, like parasitism, remain barely explored. We test whether the recent radiations of European whitefish (Coregonus spp.) across and within perialpine and subarctic lakes promote its parasite Proteocephalus fallax (Platyhelminthes: Cestoda) to undergo host repertoire expansion via opportunity and ecological fitting, or adaptive radiation by specialization. Using de novo genomic data, we examined P. fallax differentiation across lakes, within lakes across sympatric host species, and the contributions of host genetics versus host habitat use and trophic preferences. Whitefish intralake radiations prompted parasite host repertoire expansion in all lakes, whereas P. fallax differentiation remains incipient among sympatric fish hosts. Whitefish genetic differentiation per se did not explain the genetic differentiation among its parasite populations, ruling out codivergence with the host. Instead, incipient parasite differentiation was driven by whitefish phenotypic radiation in trophic preferences and habitat use in an arena of parasite opportunity and ecological fitting to utilize resources from emerging hosts. Whilst the whitefish radiation provides a substrate for the parasite to differentiate along the same water-depth ecological axis as Coregonus spp., the role of the intermediate hosts in parasite speciation may be overlooked. Parasite multiple-level ecological fitting to both fish and crustacean intermediate hosts resources may be responsible for parasite population substructure in Coregonus spp. We propose parasites' delayed arrival was key to the initial burst of postglacial intralake whitefish diversification, followed by opportunistic tapeworm host repertoire expansion and a delayed nonadaptive radiation cascade of incipient tapeworm differentiation. At the geographical scale, dispersal, founder events, and genetic drift following colonization of spatially heterogeneous landscapes drove strong parasite differentiation. We argue that these microevolutionary processes result in the mirroring of host-parasite phylogenies through phylogenetic tracking at macroevolutionary and geographical scales.

Biotope Map Creation Method and Utilization Plan for Eco-Friendly Urban Development

A biotope map provides ecological and spatial information that reflects the natural and ecological features and values of a city. In South Korea, efforts have been made to create a map that includes grades based on evaluating the ecological value of a specific surface space. However, plans for applications have not been established, except for development restrictions or regulations for biotopes with high ecological value ratings. The aim of this study was to promote environmentally friendly and sustainable urban management through ecological land use management for all biotope types that are influenced by anthropogenic land use. Strategies for maintenance, protection, recovery, improvement, creation, and reduction based on ecological restoration principles were set as management goals. To achieve these management goals, evaluation items and indicators were suggested for minor-classification types and applied to Dongducheon City. Management strategies were suggested for target sites based on grades and thematic maps of biotope types to be utilized, such as urban ecological axes, river naturality restoration, and wetland and forest preservation. These findings support sustainable and environmentally friendly urban development by providing fundamental data for ecological and environmental management, including the preservation and restoration of natural environments and the creation of urban ecological networks.

Multiple Ecological Axes Drive Molecular Evolution of Cone Opsins in Beloniform Fishes.

Ecological and evolutionary transitions offer an excellent opportunity to examine the molecular basis of adaptation. Fishes of the order Beloniformes include needlefishes, flyingfishes, halfbeaks, and allies, and comprise over 200 species occupying a wide array of habitats-from the marine epipelagic zone to tropical rainforest rivers. These fishes also exhibit a diversity of diets, including piscivory, herbivory, and zooplanktivory. We investigated how diet and habitat affected the molecular evolution of cone opsins, which play a key role in bright light and colour vision and are tightly linked to ecology and life history. We analyzed a targeted-capture dataset to reconstruct the evolutionary history of beloniforms and assemble cone opsin sequences. We implemented codon-based clade models of evolution to examine how molecular evolution was affected by habitat and diet. We found high levels of positive selection in medium- and long-wavelength beloniform opsins, with piscivores showing increased positive selection in medium-wavelength opsins and zooplanktivores showing increased positive selection in long-wavelength opsins. In contrast, short-wavelength opsins showed purifying selection. While marine/freshwater habitat transitions have an effect on opsin molecular evolution, we found that diet plays a more important role. Our study suggests that evolutionary transitions along ecological axes produce complex adaptive interactions that affect patterns of selection on genes that underlie vision.

Ecological correlates of cranial evolution in the megaradiation of dipsadine snakes

BackgroundDipsadine snakes represent one of the most spectacular vertebrate radiations that have occurred in any continental setting, with over 800 species in South and Central America. Their species richness is paralleled by stunning ecological diversity, ranging from arboreal snail-eating and aquatic eel-eating specialists to terrestrial generalists. Despite the ecological importance of this clade, little is known about the extent to which ecological specialization shapes broader patterns of phenotypic diversity within the group. Here, we test how habitat use and diet have influenced morphological diversification in skull shape across 160 dipsadine species using micro-CT and 3-D geometric morphometrics, and we use a phylogenetic comparative approach to test the contributions of habitat use and diet composition to variation in skull shape among species.ResultsWe demonstrate that while both habitat use and diet are significant predictors of shape in many regions of the skull, habitat use significantly predicts shape in a greater number of skull regions when compared to diet. We also find that across ecological groupings, fossorial and aquatic behaviors result in the strongest deviations in morphospace for several skull regions. We use simulations to address the robustness of our results and describe statistical anomalies that can arise from the application of phylogenetic generalized least squares to complex shape data.ConclusionsBoth habitat and dietary ecology are significantly correlated with skull shape in dipsadines; the strongest relationships involved skull shape in snakes with aquatic and fossorial lifestyles. This association between skull morphology and multiple ecological axes is consistent with a classic model of adaptive radiation and suggests that ecological factors were an important component in driving morphological diversification in the dipsadine megaradiation.

Visual opsin gene expression evolution in the adaptive radiation of cichlid fishes of Lake Tanganyika.

Tuning the visual sensory system to the ambient light is essential for survival in many animal species. This is often achieved through duplication, functional diversification, and/or differential expression of visual opsin genes. Here, we examined 753 new retinal transcriptomes from 112 species of cichlid fishes from Lake Tanganyika to unravel adaptive changes in gene expression at the macro-evolutionary and ecosystem level of one of the largest vertebrate adaptive radiations. We found that, across the radiation, all seven cone opsins-but not the rhodopsin-rank among the most differentially expressed genes in the retina, together with other vision-, circadian rhythm-, and hemoglobin-related genes. We propose two visual palettes characteristic of very shallow- and deep-water living species, respectively, and show that visual system adaptations along two major ecological axes, macro-habitat and diet, occur primarily via gene expression variation in a subset of cone opsin genes.

Analysis of Visitor Satisfaction Towards Provincial Parks According to Travel Route Choice Behavior Focusing on Chilgapsan Provincial Park in Chungcheongnam-do

Background and objective: Chilgapsan Provincial Park is located at the core ecological axis of Chungcheongnam-do and consists of a high share of Level 1 biotope areas, thereby requiring policy approaches for biodiversity conservation and efforts to preserve forest ecosystem services. At the same time, policies to improve service quality for visitors are needed. In particular, it is important to improve and manage service quality according to single-destination and multi-destination travel routes by subdividing visitors. The purpose of this research is to identify visitor characteristics and satisfaction towards Chilgapsan Provincial Park in Chungcheongnam-do.Methods: This study conducted frequency analysis, cross-tabulation analysis, and logit regression analysis using SPSS 21.0 version.Results: The results showed that landscape satisfaction was higher for single-destination visitors, but the overall satisfaction towards the provincial park was higher for multi-destination visitors. In addition, satisfaction towards amenities was low compared to other types of satisfaction. By travel route, visitors generally showed a high intention to revisit, with the mean exceeding 4 on the 5-point Likert scale. As a result of examining the effect on travel route through binomial logistic regression, The findings of this study have shown that age, landscape satisfaction, and visiting satisfaction had statistical significance.Conclusion: This study examined the variables that affect the satisfaction and revisit intention of visitors, improving the efficiency of provincial park management and operation. This study might be helpful to provide fundamental information for sustainable forestry management and policy measures associated with provincial parks.

Vascular flora near the iron fences in South Korea’s demilitarized zone

The demilitarized zone (DMZ), a military buffer zone between South and North Korea, is an ecological treasury free from human interference and a core ecological axis of the Korean Peninsula, making its conservation crucial. However, surveys have been insufficient because of restricted civilian access and ecosystem fragmentation. We aimed to investigate the ecological value of the DMZ and the regional characteristics of plants. A flora survey was conducted along the iron fences in the South Korean DMZ and analyzed by region. We recorded 1,051 vascular plant taxa comprising 121 families, 484 genera, 936 species, 25 subspecies, 81 varieties, and 9 formae. The region requires habitat protection because of the presence of 36 rare and 38 endemic taxa, and 35 floristic target species of Stage IV or higher. Invasive alien plants require further monitoring because 89 invasive taxa were recorded. Changes in military facilities or barren land operations can threaten habitats or create habitat edges. Biological resources, including plants, should be monitored for a multifaceted evaluation of the DMZ ecosystem value. Habitat restoration research and conservation activities should be conducted by establishing an environmental database linking environmental conditions with native plant habitats.

The Dynamic Ontogenetic Shape Patterns of Adaptive Divergence and Sexual Dimorphism

The interplay between ecological diversification and sexual dimorphism has been largely overlooked in the literature. Sexually dimorphic species which are also undergoing adaptive radiations are ideal for filling this knowledge gap. The Arctic charr in lake Thingvallavatn is one such system: it is a sexually dimorphic species which has recently diverged along the benthic-limnetic ecological axis. In a long-running common-garden experiment we studied the shape variation throughout ontogeny of intra- and inter- morph crosses of benthic and limnetic charr from the lake. We found that shape differences between ecomorphs and sexes had a genetic component. Prior to the onset of sexual maturation, shape differences were attributable to cross type and were related to adaptations to benthic and limnetic niches, i.e., shorter lower jaws and rounder snouts in the benthic and evenly protruding snouts and pointier snouts in the limnetic. Reciprocal hybrids showed intermediate, transgressive and/or maternal morphologies. However, after the onset of sexual maturation larger morphological differences occurred between sexes than among cross types. Taken together, our results demonstrate that the interplay between ecological diversification and sexual dimorphism is complex and dynamic throughout ontogeny, and that long-term common garden experiments are immensely valuable for studying shape dynamics in different evolutionary scenarios.

Divergent Specialization of Simple Venom Gene Profiles among Rear-Fanged Snake Genera (Helicops and Leptodeira, Dipsadinae, Colubridae).

Many venomous animals express toxins that show extraordinary levels of variation both within and among species. In snakes, most studies of venom variation focus on front-fanged species in the families Viperidae and Elapidae, even though rear-fanged snakes in other families vary along the same ecological axes important to venom evolution. Here we characterized venom gland transcriptomes from 19 snakes across two dipsadine rear-fanged genera (Leptodeira and Helicops, Colubridae) and two front-fanged genera (Bothrops, Viperidae; Micrurus, Elapidae). We compared patterns of composition, variation, and diversity in venom transcripts within and among all four genera. Venom gland transcriptomes of rear-fanged Helicops and Leptodeira and front-fanged Micrurus are each dominated by expression of single toxin families (C-type lectins, snake venom metalloproteinase, and phospholipase A2, respectively), unlike highly diverse front-fanged Bothrops venoms. In addition, expression patterns of congeners are much more similar to each other than they are to species from other genera. These results illustrate the repeatability of simple venom profiles in rear-fanged snakes and the potential for relatively constrained venom composition within genera.

멸종위기종 복원사업은 지역사회에 어떻게 도움이 되는가?

This study thoroughly analyzed how the endangered fox restoration project affects the community, and how much this effect contributes to improving of biodiversity and the recovery of the national ecological axis, which is the final goal of the restoration project. As a result, it was found that prerequisites such as education and promotion for protection of endangered species for local residents and visitors to the national park directly affect the restoration project goal. In addition, as an indirect route, the prerequisites for the restoration project had a positive effect on the local economy, and the regional economic effect was found to have a positive effect on the development of the local community. Finally, it was analyzed that community development contributed to achieving the goal of the restoration project. These results showed that the endangered species restoration project is contributing to the development of the local community by improving the local economy and local awareness and social value by increasing the number of tourists.

Environmental variation in sex ratios and sexual dimorphism in three wind‐pollinated dioecious plant species

Variation in plant sex ratios is often attributable to sex‐specific mortality in heterogeneous environments that differentially limit male and female plant reproduction. Yet sexual dimorphism and plastic responses to environmental heterogeneity are common and may co‐vary with variation in sex ratios. Here, we show that the sex ratio and the degree of sexual dimorphism for a number of plant traits varied along climatic and elevation gradients in three wind‐pollinated dioecious species, Rumex lunaria, Urtica dioica and Salix helvetica. Some of the observed sex‐specific responses to climatic variation are consistent with greater sensitivity of females to water scarcity, but most responses rather point to the greater sensitivity of males to ecological stress, consistent with larger male reproductive effort, as has been commonly reported for wind‐pollinated plants. In contrast, we found no evidence for variation in either sex ratios or sexual dimorphism expected under sexual selection. Interestingly, sex ratios and sexual dimorphism varied both along distinct and the same ecological axes of variation, suggesting that the evolution of sexual dimorphism in the measured traits was not sufficient to prevent sex‐specific mortality.

Natural and anthropogenic noise increase vigilance and decrease foraging behaviors in song sparrows

Abstract Animals glean information about risk from their habitat. The acoustic environment is one such source of information, and is an important, yet understudied ecological axis. Although anthropogenic noise has become recently ubiquitous, risk mitigation behaviors have likely been shaped by natural noise over millennia. Listening animals have been shown to increase vigilance and decrease foraging in both natural and anthropogenic noise. However, direct comparisons could be informative to conservation and understanding evolutionary drivers of behavior in noise. Here, we used 27 song sparrows (Melospiza melodia) and 148 laboratory behavioral trials to assess foraging and vigilance behavior in both anthropogenic and natural noise sources. Using five acoustic environments (playbacks of roadway traffic, a whitewater river, a whitewater river shifted upwards in frequency, a river with the amplitude modulation of roadway traffic, and an ambient control), we attempt to parse out the acoustic characteristics that make a foraging habitat risky. We found that sparrows increased vigilance or decreased foraging in 4 of 6 behaviors when foraging in higher sound levels regardless of the noise source or variation in frequency and amplitude modulation. These responses may help explain previously reported declines in abundance of song sparrows exposed to playback of intense river noise. Our results imply that natural soundscapes have likely shaped behavior long before anthropogenic noise, and that high sound levels negatively affect the foraging-vigilance trade-off in most intense acoustic environments. Given the ever-increasing footprint of noise pollution, these results imply potential negative consequences for bird populations.

A theoretical study on the landscape of the Korean DMZ and its spatial significance

ABSTRACT Recently, the two Koreas are also seeking new relations. This study pays attention to the fact that these domestic and international changes provide an opportunity to expand research on the DMZ in the Korean Peninsula, and has approached the space of the DMZ as a landscape from a more specific and realistic perspective. First, the Cold War landscape of the Korean DMZ has historical and political significance in that it is the last remaining site in the history of the Cold War. It is also as a barrier that divides North and South Korea, and a symbolic location for the peace process on the Korean Peninsula. Second, the ecological landscape of the DMZ suggests that it has the potential to function as a core ecological axis in the Korean Peninsula due to its natural attributes. Lastly, the cultural significance of the DMZ as a symbolic space representing the people’s aspirations for peace is being transformed through various cultural and educational programs. This paper confirms that the space of the Korean DMZ is gradually changing its significance from a Cold War landscape to a landscape of cultural symbols representing people’s wish for peace.

The global biogeography of lizard functional groups

AbstractAimUnderstanding the mechanisms determining species richness is a primary goal of biogeography. Richness patterns of sub‐groups within a taxon are usually assumed to be driven by similar processes. However, if richness of distinct ecological strategies respond differently to the same processes, inferences made for an entire taxon may be misleading. We deconstruct the global lizard assemblage into functional groups and examine the congruence among richness patterns between them. We further examine the species richness – functional richness relationship to elucidate the way functional diversity contributes to the overall species richness patterns.LocationGlobal.MethodsUsing comprehensive biological trait databases we classified the global lizard assemblage into ecological strategies based on body size, diet, activity times and microhabitat preferences, using Archetypal Analysis. We then examined spatial gradients in the richness of each strategy at the one‐degree grid cell, biome, and realm scales.ResultsWe found that lizards can best be characterized by seven “ecological strategies”: scansorial, terrestrial, nocturnal, herbivorous, fossorial, large, and semi‐aquatic. There are large differences among the global richness patterns of these strategies. While the major richness hotspot for lizards in general is in Australia, several strategies exhibit highest richness in the Amazon Basin. Importantly, the global maximum in lizard species richness is achieved at intermediate values of functional diversity and increasing functional diversity further result in a slow decline of species richness.Main conclusionsThe deconstruction of the global lizard assemblage along multiple ecological axes offers a new way to conceive lizard diversity patterns. It suggests that local lizard richness mostly increases when species belonging to particular ecological strategies become hyper‐diverse there, and not because more ecological types are present in the most species rich localities. Thus maximum richness and maximum ecological diversity do not overlap. These results shed light on the global richness pattern of lizards, and highlight previously unidentified spatial patterns in understudied functional groups.

A framework for conservation area designation utilizing an ecotope concept and its application to a mountainous national park in Korea

This study focused on establishing a framework for the designation of a conservation area reflecting an ecotope concept, and its application to Korea’s Seoraksan National Park. Taking into consideration the mountainous topography of the study area, the watershed was chosen as the planning unit, and ecotope mapping was carried out to identify topographic and biological features. For the evaluation of the state of recent use, the trail index and the distribution status of tour and management facilities were used. These features were processed using Marxan with Zones. As a result, the optimal solution of scenario 1 was selected as the final one following detailed verification of the area ratio and grouping of the Park Nature Conservation Area (zone A, 76.7%) and the Park Nature Environment Area (I) (zone B, 14.3%), the inclusion ratio of biotope grade I (95.2%) and the satisfied shortfall value of the conservation indicators. In the overlap analysis between the optimal solution and recent zonation, most of the features included in the suggested scenario were found to be correctly distributed according to the intensity of conservation. Furthermore, the northern parts of the watershed which include sub-alpine vegetation with the Baekdudaegan ridge as its ecological axis was newly separated into the Park Conservation Area. This verification confirmed the improvement of recent zonation through the concrete criteria of ecotope mapping.

Allopatric Speciation Drives Diversification of Ecological Specialists on Sandhills

Premise of research. The evolution of lineages on continental edaphic islands has been an important determinant of diversification. To understand the complexities of continental edaphic diversification, the historical, biogeographic, and ecological aspects of the diversification process must be studied, even when the relative contributions of ecological and nonecological processes are difficult to differentiate. To decipher the ecological determinants of diversification on continental edaphic islands, we examined the diversification of the plant genus Paronychia (Caryophyllaceae) that occurs on sandhills across the three ecological axes that follow: habitat, soil chemistry, and bioclimate.Methodology. A phylogenetic hypothesis of Paronychia was reconstructed, and ecological variables were measured in natural populations to determine the key axes of diversification. We tested an allopatric model that made predictions based on new habitat formation as sea levels lowered and sand ridges formed, as well as an ecological divergence hypothesis. Ecological variation was summarized with principal component analyses and subjected to several phylogenetic diversification models. Ecological niche modeling approaches were applied to determine whether species were ecologically diversifying across a bioclimate axis.Pivotal results. Although Paronychia is ecologically conservative in occurring on sandy, dry, and open soils, we identified substantial ecological variation, in which individuals occupied greater ecological space within rather than between species. Despite substantial variation, species had not partitioned into unique ecological space. Instead, we found that allopatric speciation based on the geological appearance of habitats was supported and is a key determinant of diversity.Conclusions. Our findings highlight the role of phylogenetic niche conservatism and allopatric speciation for similar, yet disjunct, habitats as species diversified across continental edaphic islands. Despite species occupying similar niche space, our results suggest that niche envelopes can be quite broad and that diversity is dependent on the extent of habitat isolation.

The ecological and life history correlates of boldness in free‐ranging lizards

AbstractIn many animal populations, individuals exhibit repeatable behavioral traits across a range of contexts, and similarly, individuals differ in ecological traits such as habitat use, home range sizes, growth rates, and mating success. However, links between an individual's positions on behavioral vs. ecological axes of variation remain relatively unstudied in the wild. In the course of fieldwork on a remote floodplain in tropical Australia, we quantified boldness and ecological traits in 86 free‐ranging (radio‐tracked) monitor lizards (Varanus panoptes). These large (up to 7 kg) lizards exhibited a spectrum of boldness, as reflected in correlated scores of responses to approach, handling, and novel prey. Bolder lizards had larger core home ranges and higher mating success and spent more time in areas of high predator abundance, and their seasonal regimes of predation‐induced mortality differed from those of shyer lizards. Thus, behavioral differences among lizards underpin much of the variation in ecological traits and individual fitness within this population. Analyses of ecology and microevolution in natural populations cannot afford to ignore the complex covariation between behavior, ecology, and evolution in the wild.

Root traits across environmental gradients in Mediterranean woody communities: are they aligned along the root economics spectrum?

Root traits play a critical role in plant resource-use strategies and ecosystem functioning, but there is great controversy regarding their identity and functionality in different dimensions of belowground functional variation. Here, we explored the level of covariation among a suite of key root traits (i.e. specific root length, root dry matter content, diameter and density) as well as between them and two aboveground traits related with plant function (leaf nutrient concentration and specific leaf area). We also evaluated whether these patterns of trait covariation were consistent at different spatial scales and organisational levels. We collected fine root (< 2 mm) samples of 534 individuals (of 80 woody species) along a wide regional range of environmental conditions in southern Spain. In general, strong correlations among most of the root morphological traits were found, supporting the existence of a ‘root economics spectrum’, as well as between root traits and the aboveground traits. However, root diameter was not completely aligned along this ecological axis, supporting the idea of a multidimensional spectrum of root traits. The main syndrome of root trait covariation was consistent at the different spatial scales and organisational levels. Soil nutrients and water availability were the main drivers of root trait variation. Our results indicate that root trait variation is primarily aligned along a leading dimension related to resource economics. However, the distinct pattern of root diameter may indicate a multidimensionality of belowground traits that needs to be explored in greater depth.