Global bioregions of reptiles confirm the consistency of bioregionalization processes across vertebrate clades

Aim

The identification of biogeographical zones has been fundamental in broadscale biodiversity analyses over the last 150 years. If processes underlying bioregionalization, such as climatic differences, tectonics and physical barriers, are consistent across vertebrate clades, we expect that groups with more similar ecological characteristics would show more similar bioregions. Lack of data has so far hampered the delineation of global bioregions for reptiles. Therefore, we integrated comprehensive geographic distribution and phylogenetic data of lepidosaurian reptiles to delineate global reptile bioregions, compare determinants of biogeographical boundaries across terrestrial vertebrates and test whether clades showing similar responses to environmental factors also show more similar bioregions.

Location

Global.

Time Period

Present.

Major Taxa Studied

Reptiles, amphibians, birds, mammals.

Methods

For reptiles, we used phylogenetic beta diversity to quantify changes in community composition, and hierarchical clustering to identify biogeographic ‘realms’ and ‘regions’. Then, we assessed the determinants of biogeographical boundaries using spatially explicit regression models, testing the effect of climatic factors, physical barriers and tectonics. Bioregions of reptiles were compared to those of other vertebrate clades by testing the overall similarity of the spatial structure of bioregions, and the match of the position of biogeographical boundaries.

Results

For reptiles, we identified 24 evolutionarily unique regions, nested within 14 realms. Biogeographical boundaries of reptiles were related to both climatic factors and past tectonic movements. Bioregions were very consistent across vertebrate clades. Bioregions of reptiles and mammals showed the highest similarity, followed by reptiles/birds and mammals/birds while amphibian bioregions were less similar to those of the other clades.

Main Conclusions

The overall high similarity among bioregions suggests that bioregionalization was affected by similar underlying processes across terrestrial vertebrates. Nevertheless, clades with different eco-physiological characteristics respond somewhat differently to the same environmental factors, resulting in similar but not identical regionalizations across vertebrate clades.     

Lack of general associations between intertidal assemblages and rock hardness

Different assemblages of intertidal biota may be associated with the hardness of the rock type that comprises the seashore. However, very few published studies have investigated mobile and sessile assemblage differences between hardness classes. To remedy this, we investigated the physical attributes and biotic assemblages of 12 rock platforms across two bioregions, encompassing seven rock types categorised into either the soft (≤4 using Moh’s scale of scratch hardness) or hard (>4 on Moh’s scale) classes. Rock types from the soft versus hard classes differed physically, but the biotic assemblages showed few general differences between hardness classes. Instead, most biotic differences associated with rock hardness were specific to just one of the marine bioregions sampled, not both. Hardness-related assemblage differences were only weakly-to-moderately correlated with hardness differences in mineralogy or microhabitat density. The detection of bioregion-specific hardness differences for intertidal assemblages, rather than general hardness class trends, indicate that the type of rock comprising the seashore in each bioregion may be more strongly associated with the biotic patterns identified than hardness per se.     

The need for richness‐independent measures of turnover when delineating biogeographical regions

Delineating biogeographical regions is one of the primary steps when analysing biogeographical patterns. In their proposed quantitative framework, Kreft & Jetz (2010, Journal of Biogeography, 37 , 2029–2053) recommended the use of the β_sim index to delineate biogeographical regions because this turnover measure is weakly affected by differences in species richness between localities. A recent study by Carvalho et al. (2012, Global Ecology and Biogeography, 21 , 760–771) critiziced the use of β_sim in ecological and biogeographical studies, and proposed the β_‐3 index. Here we used simple numerical examples and an empirical case study (European freshwater fishes) to highlight potential pitfalls associated with the use of β_‐3 for bioregionalization. We show that β_‐3 is not a richness‐independent measure of species turnover. We also show that this index violates the ‘complementarity’ property, namely that localities without species in common have the largest dissimilarity, which is an essential prerequisite for beta diversity studies.     

Using co‐occurrence network topology in assessing ecological stress in benthic macroinvertebrate communities

Ecological monitoring of streams has often focused on assessing the biotic integrity of individual benthic macroinvertebrate (BMI) communities through local measures of diversity, such as taxonomic or functional richness. However, as individual BMI communities are frequently linked by a variety of ecological processes at a regional scale, there is a need to assess biotic integrity of groups of communities at the scale of watersheds. Using 4,619 sampled communities of streambed BMIs, we investigate this question using co‐occurrence networks generated from groups of communities selected within California watersheds under different levels of stress due to upstream land use. Building on a number of arguments in theoretical ecology and network theory, we propose a framework for the assessment of the biotic integrity of watershed‐scale groupings of BMI communities using measures of their co‐occurrence network topology. We found significant correlations between stress, as described by a mean measure of upstream land use within a watershed, and topological measures of co‐occurrence networks such as network size (r = ?.81, p < 10^–4), connectance (r = .31, p < 10^–4), mean co‐occurrence strength (r = .25, p < 10^–4), degree heterogeneity (r = ?.10, p < 10^–4), and modularity (r = .11, p < 10^–4). Using these five topological measures, we constructed a linear model of biotic integrity, here a composite of taxonomic and functional diversity known as the California Stream Condition Index, of groups of BMI communities within a watershed. This model can account for 66% of among‐watershed variation in the mean biotic integrity of communities. These observations imply a role for co‐occurrence networks in assessing the current status of biotic integrity for BMI communities, as well as their potential use in assessing other ecological communities.     

Response of three lotic assemblages to riparian and catchment‐scale land use: implications for designing catchment monitoring programmes

1. Although many studies have focussed on the effects of catchment land use on lotic systems, the importance of broad (catchment) and fine (segment/reach) scale effects on stream assemblages remain poorly understood. 2. Nine biological metrics for macrophytes (498 sites), benthic macroinvertebrates (491) and fish (478) of lowland and mountain streams in four ecoregions of France and Germany were related to catchment and riparian buffer land use using partial Redundancy Analysis and Boosted Regression Trees (BRTs). 3. Lotic fauna was better correlated (mean max., r = 0.450) than flora (r = 0.277) to both scales of land use: the strongest correlations were noted for mountain streams. BRTs revealed strong non‐linear relationships between mountain assemblage metrics and land use. Correlations increased with increasing buffer lengths, suggesting the importance of near‐stream land use on biotic assemblages. 4. Several metrics changed markedly between 10–20% (mountain ecoregions) and 40–45% (lowland) of arable land use, irrespective of the buffer size. At mountain sites with >10% catchment arable land use, metric values differed between sites with <30% and sites with >30% forest in the near‐stream riparian area. 5. These findings support the role of riparian land use in catchment management; however, differences between mountain and lowland ecoregions support the need for ecoregion‐specific management.     

The importance of temperate woodland in travelling stock reserves for vertebrate biodiversity conservation

Summary Travelling stock reserves have well recognised and important commercial, cultural and other values in the pastoral and agricultural regions of Australia, but their conservation values remain poorly known. In general, many areas of woodlands within travelling stock reserves have not been subjected to the same high levels of degradation pressure as similar temperate woodlands on private land. In this study, we compared several measures of vertebrate biota in 217 permanent field sites located in travelling stock reserves and woodland remnants located almost exclusively on private land in the Murray Riverina and South West Slopes bioregions in southern New South Wales. We found that in comparison with temperate woodland remnants on private land, temperate woodland in travelling stock reserves tended to support more species of birds, more species of declining birds, and a greater abundance of arboreal marsupials. Temperate woodland in travelling stock reserves was more likely to be occupied by particular individual species of birds of conservation concern. However, such tenure differences were not consistent between bioregions. For example, the Rufous Whistler (Pachycephala rufiventris) and the Red‐capped Robin (Petroica goodenovii ) were significantly more likely to occupy temperate woodland in travelling stock reserves than temperate woodland on private land in the Murray Riverina but such effects were not apparent in the South West Slopes. Similarly, while the Grey‐crowned Babbler (Pomatostomus temporalis) was significantly more likely to occupy temperate woodland in travelling stock reserve sites in the South West Slopes, we found the opposite effect in Murray Riverina. We demonstrated that travelling stock reserves have important conservation values for some taxa and individual species. Because of the paucity of large ecological reserves in the Murray Riverina and South West Slopes bioregions, temperate woodlands located in travelling stock reserves should be considered as an important resource that contributes to a portfolio of vegetation assets in formerly woodland‐dominated, but now extensively cleared, agricultural landscapes.     

Seed mass and seedling establishment after fire in Ku‐ring‐gai Chase National Park,Sydney, Australia

Abstract Relationships between seed mass and several aspects of plant regeneration ecology were investigated in a post‐fire environment in Ku‐ring‐gai Chase National Park near Sydney, Australia. We found a significant positive relationship between seed mass and time to seedling emergence (P < 0.001) and a strong negative relationship between seed mass and time between emergence and production of the first true leaf (P < 0.001). Surprisingly, we found no relationship between seed mass and seedling establishment (P = 0.21). It seems most likely that this lack of relationship is a result of the many stochastic factors affecting seedling establishment during any given recruitment episode at any given site. A cause of mortality was assigned to 56% of the 781 seedlings that died during the present study. There was no relationship between cause of death and seed mass (P = 0.28). Of the seedlings for which the cause of death was known, 57% were killed by herbivory and 21% were killed by drought. Seedling–seedling competition affected only one species.     

Positive co‐occurrence between feeding‐associative savannah fishes depends on species and habitat

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Spatiotemporal dynamics of α‐ and β‐diversity across topographic gradients in the herbaceous layer of an old‐growth deciduous forest

Understanding the factors that regulate biodiversity over spatial and temporal gradients is an important scientific objective with ramifications for theory and conservation. Species composition is known to vary across spatial gradients, but how this spatial variation is linked to temporal dynamics is less well studied. Our objective was to understand how Shannon (α) diversity, spatial species turnover (Bray–Curtis dissimilarity), and temporal species turnover (Bray–Curtis dissimilarity) varied with regard to three topographic gradients (aspect, slope and elevation) over one growing season. In April, June and August of 2011, the herbaceous layer was sampled in 320 1‐m² plots within Big Everidge Hollow, an old‐growth forest in southeastern Kentucky. Multiple regression models revealed that Shannon diversity was linearly related to aspect (negative) and slope (positive), but unimodally related to elevation, indicating steep, mid‐elevation, and south‐facing plots were most diverse. Distance decay analysis showed that significant spatial species turnover occurred across all three topographic gradients, but aspect and elevation had a greater influence on compositional dissimilarity than slope. Mean temporal species turnover was significantly greater (p < 0.001) between April and June (0.39 ± 0.02 SE) than between June and August (0.20 ± 0.01). April‐to‐June turnover was related to aspect (linear) and elevation (quadratic; r²= 0.23, p < 0.0001), suggesting greater temporal species turnover occurred on north‐facing and mid‐elevation plots during this period; however, June‐to‐August turnover was weakly related to slope only (positive linear; r²= 0.08, p = 0.006). Environmental heterogeneity generated by topography is one of many factors that may constrain or promote biodiversity through space and across time, and a solid understanding of these spatiotemporal patterns of diversity can benefit both conservation and ecological theory.     

APPLIED ISSUES: Exploring the response of functional indicators of stream health to land‐use gradients

1. Broad‐scale assessment of stream health is often based on correlative relationships between catchment land‐use categories and measurements of stream biota or water chemistry. Few studies have attempted to characterise the response curves that describe how measures of ecosystem function change along gradients of catchment land use, or explored how these responses vary at broad spatial scales. 2. In autumn 2008, we conducted a survey of 84 streams in three bioregions of New Zealand to assess the sensitivity of functional indicators to three land‐use gradients: percentage of native vegetation cover, percentage of impervious cover (IC) and predicted nitrogen (N) concentration. We examined these relationships using general linear models and boosted regression trees to explore monotonic, non‐monotonic and potential threshold components of the response curves. 3. When viewing the responses to individual land‐use gradients, four of five functional indicators were positively correlated with the removal of native vegetation cover and N. In general, weaker and less responsive models were observed for the IC gradient. An analysis of the response to multiple stressors showed δ¹⁵N of primary consumers and gross primary productivity (GPP) to be the most responsive functional indicators to land‐use gradients. The multivariate models identified thresholds for change in the relationship between the functional indicators and all three land‐use gradients. Apparent thresholds were <10%IC, between 40 and 80% loss of native vegetation cover and at 0.5 and 3.2 mg L^?1 N. 4. The strength of regression models and the nature of the response curves suggest that measures of ecosystem function exhibit predictable relationships with land use. Furthermore, the responses of functional indicators varied little among three bioregions. This information provides a strong argument for the inclusion of functional indicators in a holistic assessment of stream health.     

Biogeographical network analysis of plant species distribution in the Mediterranean region

The delimitation of bioregions helps to understand historical and ecological drivers of species distribution. In this work, we performed a network analysis of the spatial distribution patterns of plants in south of France (Languedoc‐Roussillon and Provence‐Alpes‐Côte d'Azur) to analyze the biogeographical structure of the French Mediterranean flora at different scales. We used a network approach to identify and characterize biogeographical regions, based on a large database containing 2.5 million of geolocalized plant records corresponding to more than 3,500 plant species. This methodology is performed following five steps, from the biogeographical bipartite network construction to the identification of biogeographical regions under the form of spatial network communities, the analysis of their interactions, and the identification of clusters of plant species based on the species contribution to the biogeographical regions. First, we identified two sub‐networks that distinguish Mediterranean and temperate biota. Then, we separated eight statistically significant bioregions that present a complex spatial structure. Some of them are spatially well delimited and match with particular geological entities. On the other hand, fuzzy transitions arise between adjacent bioregions that share a common geological setting, but are spread along a climatic gradient. The proposed network approach illustrates the biogeographical structure of the flora in southern France and provides precise insights into the relationships between bioregions. This approach sheds light on ecological drivers shaping the distribution of Mediterranean biota: The interplay between a climatic gradient and geological substrate shapes biodiversity patterns. Finally, this work exemplifies why fragmented distributions are common in the Mediterranean region, isolating groups of species that share a similar eco‐evolutionary history.     

The Fire Refuge Value of Patches of a Fire‐Sensitive Tree in Fire‐prone Savannas: Callitris intratropica in Northern Australia

Patches of fire‐sensitive vegetation often occur within fire‐prone tropical savannas, and are indicative of localized areas where fire regimes are less severe. These may act as important fire refugia for fire‐sensitive biota. The fire‐sensitive tree Callitris intratropica occurs in small patches throughout the fire‐prone northern Australian savannas, and is widely seen as an indicator of low‐severity fire regimes and of good ecosystem health. Here, we address the question: to what extent do Callitris patches act as refuges for other fire‐sensitive biota, and therefore play a broader conservation role? We contrast floral and faunal species composition between Callitris patches and surrounding eucalypt savanna, using three case studies. In the first case study, a floristic analysis of 47 Callitris patches across Western Australia's Kimberley region showed that woody species in these patches were overwhelmingly widespread, fire‐tolerant savanna taxa. No species of special conservation concern occurred disproportionately within Callitris patches. Similarly, there was no concentration of fire‐sensitive fauna or flora in five Callitris patches in the East Kimberley. Finally, there was no difference in ant species composition among 12 Callitris patches and surrounding eucalypt savannas in Kakadu National Park, Northern Territory, and there were no fire‐sensitive ant species in Callitris patches. Our three case studies from throughout the northwestern Australia provide no evidence that Callitris patches act as important refuges for fire‐sensitive flora or fauna within fire‐prone eucalypt savannas. This calls into question the notion that Callitris is a strong indicator of general ecosystem health.     

Niche specificity influences gene flow across fine‐scale habitat mosaics in Succulent Karoo plants

While the tempo of diversification in biodiversity hotspots has received much attention, the spatial scale of diversification has often been overlooked. Addressing this deficiency requires understanding the drivers of population divergence and the spatial scales at which they operate in species‐rich clades and ecosystems. South Africa's Succulent Karoo (SK) hotspot provides an excellent system for such research, being both compact (ca. 110,000 km²) and home to spectacular in‐situ radiations, such as the ruschioid Aizoaceae. Here we use GBS to document genetic structure in two co‐occurring ruschioid species, at both coarse (>10 km) and fine (<500 m) spatial scales. Where Ruschia burtoniae shows strong between‐population genetic differentiation and no gene flow, Conophytum calculus shows weak differentiation, with high levels of admixture suggesting recent or ongoing gene flow. Community analysis and transplant experiments reveal that R. burtoniae occupies a narrow, low‐pH edaphic niche, and at scales of a few hundred metres, areas of elevated genetic turnover correspond to patches of edaphically unsuitable habitat. In contrast, C. calculus occupies a broader niche and exhibits isolation‐by‐distance without a habitat effect. We suggest that edaphic specialisation, coupled with highly restricted seed and pollen dispersal in heterogeneous landscapes, has played a major role in driving rapid diversification at small spatial scales in this system. However, the contrasting patterns in our study species show that these factors do not influence all organisms uniformly, being strongly modulated by lineage‐specific traits that influence both the spatial scale of gene flow and habitat specificity.     

Muscle Type‐Dependent Responses to Insulin in Intramyocellular Triglyceride Turnover in Obese Rats

Objective: To understand the role of hyperinsulinemia in intramyocellular (imc) triglyceride (TG) accumulation and in regulating imcTG turnover. Research Methods and Procedures: imcTG was first prelabeled by continuous infusion of [U‐¹⁴C]glycerol (pulse), and then the rate of label loss from the prelabeled imcTG pool (turnover) in gastrocnemius, tibialis anterior, and soleus muscle of awake, high‐fat‐fed obese rats during the subsequent hyperinsulinemic‐euglycemic clamp experiments (chase) was determined. Results: Post‐absorptive basal fractional imcTG turnover rate in soleus was 0.010 ± 0.001/min, significantly lower than that in gastrocnemius (0.026 ± 0.002/min, p < 0.001) or tibialis anterior (0.030 ± 0.002/min, p < 0.0001), a pattern reciprocal to their imcTG pool size. Insulin infusion at 25 pmol/kg per minute resulted in pathophysiological hyperinsulinemia (5‐fold increase over the baseline value). This caused an increase in imcTG turnover by 3‐fold in soleus (0.029 ± 0.006/min, p = 0.002) but a decrease in gastrocnemius (0.012 ± 0.003/min, p = 0.001) and in tibialis anterior (0.0064 ± 0.001/min, p < 0.0001). Pathophysiological hyperinsulinemia suppressed hormone‐sensitive lipase activity in heart (p = 0.01) and mesenteric fat (p = 0.05) but not in skeletal muscle (p > 0.05). The pool size of imcTG was not affected by hyperinsulinemia. Discussion: The results demonstrated muscle‐type dependence in the response of imcTG turnover to hyperinsulinemia in the obesity model. The reciprocal insulin effects on imcTG turnover in oxidative vs. oxidative‐glycolytic muscle indicated a possibility that oxidative muscle contributes more to insulin resistance under hyperinsulinemia if imcTG‐fatty acid oxidation is a function of turnover. imcTG turnover does not seem to regulate imcTG pool size acutely.     

Spatial variation in the climatic predictors of species compositional turnover and endemism

Previous research focusing on broad‐scale or geographically invariant species‐environment dependencies suggest that temperature‐related variables explain more of the variation in reptile distributions than precipitation. However, species–environment relationships may exhibit considerable spatial variation contingent upon the geographic nuances that vary between locations. Broad‐scale, geographically invariant analyses may mask this local variation and their findings may not generalize to different locations at local scales. We assess how reptile–climatic relationships change with varying spatial scale, location, and direction. Since the spatial distributions of diversity and endemism hotspots differ for other species groups, we also assess whether reptile species turnover and endemism hotspots are influenced differently by climatic predictors. Using New Zealand reptiles as an example, the variation in species turnover, endemism and turnover in climatic variables was measured using directional moving window analyses, rotated through 360°. Correlations between the species turnover, endemism and climatic turnover results generated by each rotation of the moving window were analysed using multivariate generalized linear models applied at national, regional, and local scales. At national‐scale, temperature turnover consistently exhibited the greatest influence on species turnover and endemism, but model predictive capacity was low (typically r² = 0.05, P < 0.001). At regional scales the relative influence of temperature and precipitation turnover varied between regions, although model predictive capacity was also generally low. Climatic turnover was considerably more predictive of species turnover and endemism at local scales (e.g., r² = 0.65, P < 0.001). While temperature turnover had the greatest effect in one locale (the northern North Island), there was substantial variation in the relative influence of temperature and precipitation predictors in the remaining four locales. Species turnover and endemism hotspots often occurred in different locations. Climatic predictors had a smaller influence on endemism. Our results caution against assuming that variability in temperature will always be most predictive of reptile biodiversity across different spatial scales, locations and directions. The influence of climatic turnover on the species turnover and endemism of other taxa may exhibit similar patterns of spatial variation. Such intricate variation might be discerned more readily if studies at broad scales are complemented by geographically variant, local‐scale analyses.     

Quantifying High Resolution Transitional Breaks in Plant and Mammal Distributions at Regional Extent and Their Association with Climate,Topography and Geology

Objectives

We quantify spatial turnover in communities of 1939 plant and 59 mammal species at 2.5 km resolution across a topographically heterogeneous region in south-eastern Australia to identify distributional breaks and low turnover zones where multiple species distributions overlap. Environmental turnover is measured to determine how climate, topography and geology influence biotic turnover differently across a variety of biogeographic breaks and overlaps. We identify the genera driving turnover and confirm the versatility of this approach across spatial scales and locations.

Methods

Directional moving window analyses, rotated through 360°, were used to measure spatial turnover variation in different directions between gridded cells containing georeferenced plant and mammal occurrences and environmental variables. Generalised linear models were used to compare taxic turnover results with equivalent analyses for geology, regolith weathering, elevation, slope, solar radiation, annual precipitation and annual mean temperature, both uniformly across the entire study area and by stratifying it into zones of high and low turnover. Identified breaks and transitions were compared to a conservation bioregionalisation framework widely used in Australia.

Results/Significance

Detailed delineations of plant and mammal turnover zones with gradational boundaries denoted subtle variation in species assemblages. Turnover patterns often diverged from bioregion boundaries, though plant turnover adhered most closely. A prominent break zone contained either comparable or greater numbers of unique genera than adjacent overlaps, but these were concentrated in a small subsection relatively under-protected by conservation reserves. The environmental correlates of biotic turnover varied for different turnover zones in different subsections of the study area. Topography and temperature showed much stronger relationships with plant turnover in a topographically complex overlap, relative to a lowland overlap where weathering was most predictive. This method can quantify transitional turnover patterns from small to broad extents, at different resolutions for any location, and complements broad-scale bioregionalisation schemes in conservation planning.     

How well documented is Australia's flora? Understanding spatial bias in vouchered plant specimens

Massive digitization of natural history collections (NHC) has opened the door for researchers to conduct inferential studies on the collection of biological diversity across space and time. The widespread use of NHCs in scientific research makes it essential to characterize potential sources of spatial bias. In this study, we assessed spatial patterns in records from the Australian Virtual Herbarium (AVH), based on >3 000 000 vouchered specimens of around 21 000 native plant species. The AVH is the main database for describing Australia's flora, and identifying its limitations is of paramount interest for the validity of conservation and environmental studies. We characterized how sampling effort is distributed across each Interim Bioregion of Australia (IBRA), then asked: (i) How complete are species inventories for each bioregion? We define completeness (C) as the ratio of observed to estimated species richness, using the Chao 1 estimator, (ii) How is sampling effort related to a commonly used Human Influence Index (HII)? and (iii) What is the probability that additional collections would result in the identification of previously unrecorded species in each bioregion? Sampling effort across bioregions is unequal, which partially reflects the collecting behaviour of naturalists in relation to species richness patterns. The density of records in bioregions ranges from 0.02–8.37 km^?2. At the bioregional scale, completeness is generally high with 79% of bioregions estimated to have records for at least 80% of their species. Completeness is partly explained by sampling effort (r = 0.43, p = 0.01), although some bioregions (e.g. Northern Kimberley and Burt Plain) have high completeness yet relatively low sampling effort. The inventory of Hampton, however, is substantially less complete than other bioregions (C = 0.66). Bioregions with high HII consistently have high completeness, while regions with low HII span the full range of completeness values. We calculated that an additional specimen collected from a bioregion has a 0.33% (Wet Tropics) to 11.7% (Arnhem Coast) probability of representing a new species for that region. Our assessment can assist with directing future systematic survey efforts by identifying bioregions where additional surveying may result in the greatest return, in terms of increasing knowledge of species richness and diversity.     

Application of a Gondwanan perspective to restore ecological integrity in the south‐western Australian global biodiversity hotspot

Bounded by ocean and desert, the isolated, predominately Mediterranean‐climate region of south‐western Australia (SWA) includes nine bioregions (circa 44 million hectares). The ecological integrity of the landscapes in this global biodiversity hotspot has been compromised by deforestation, fragmentation, exploitation, and introduced biota. Nature and degree of transformation varies between four interconnected landscapes (Swan Coastal Plain; South‐west Forests; Wandoo Woodlands; and Great Western Woodlands). A Gondwanan perspective emphasizes a venerable biota and a cultural component to deep time. The particular importance of remnants and protected areas is recognized in restoring ecological integrity to Gondwanan landscapes. The nature and magnitude of the restoration task in these ancient, and neighboring, landscapes require higher levels of investment and more time than do recent landscapes. The protection, conservation, restoration, and rehabilitation of ecological integrity require multiple approaches in each landscape as well as consideration of the whole. Active conservation of biota and minimizing the impact of industrial‐ and agricultural‐use are priorities. Integrating a climate focus and rethinking fire are critical restoration considerations to future trajectories under anthropogenic climate change. A legislative mandate to coordinate industrial‐scale restoration and active conservation to build from protected areas must become a societal priority to restore ecological integrity.     

Dual‐energy X‐ray Absorptiometry and Anthropometric Estimates of Visceral Fat in Black and White South African Women

Visceral adipose tissue (VAT) is associated with increased risk for cardiovascular disease, and therefore, accurate methods to estimate VAT have been investigated. Computerized tomography (CT) is the gold standard measure of VAT, but its use is limited. We therefore compared waist measures and two dual‐energy X‐ray absorptiometry (DXA) methods (Ley and Lunar) that quantify abdominal regions of interest (ROIs) to CT‐derived VAT in 166 black and 143 white South African women. Anthropometry, DXA ROI, and VAT (CT at L4–L5) were measured. Black women were younger (P < 0.001), shorter (P < 0.001), and had higher body fat (P < 0.05) than white women. There were no ethnic differences in waist (89.7 ± 18.2 cm vs. 90.1 ± 15.6 cm), waist:height ratio (WHtR, 0.56 ± 0.12 vs. 0.54 ± 0.09), or DXA ROI (Ley: 2.2 ± 1.5 vs. 2.1 ± 1.4; Lunar: 2.3 ± 1.4 vs. 2.3 ± 1.5), but black women had less VAT, after adjusting for age, height, weight, and fat mass (76 ± 34 cm² vs. 98 ± 35 cm²; P < 0.001). Ley ROI and Lunar ROI were correlated in black (r = 0.983) and white (r = 0.988) women. VAT correlated with DXA ROI (Ley: r = 0.729 and r = 0.838, P < 0.01; Lunar: r = 0.739 and r = 0.847, P < 0.01) in black and white women, but with increasing ROI android fatness, black women had less VAT. Similarly, VAT was associated with waist (r = 0.732 and r = 0.836, P < 0.01) and WHtR (r = 0.721 and r = 0.824, P < 0.01) in black and white women. In conclusion, although DXA‐derived ROIs correlate well with VAT as measured by CT, they are no better than waist or WHtR. Neither DXA nor anthropometric measures are able to accurately distinguish between high and low levels of VAT between population groups.     

The differential impact of a native and a non‐native ragwort species (Senecioneae) on the first and second trophic level of the rhizosphere food web

Whereas the impact of exotic plant species on above‐ground biota is relatively well‐documented, far less is known about the effects of non‐indigenous plants on the first and second trophic level of the rhizosphere food web. Here, rhizosphere communities of the invasive narrow‐leaved ragwort Senecio inaequidens and the native tansy ragwort Jacobaea vulgaris, co‐occurring in three semi‐natural habitats are compared. For both species, two life stages were taken into consideration. Quantitative PCR assays for the analyses of bacterial and fungal communities at a high taxonomic level were optimized, and it was investigated whether changes in the primary decomposer community were translated in alterations in bacterivorous and fungivorous nematode communities. In contrast to J. vulgaris, small but significant reductions were observed for Actinobacteria and Bacteroidetes (both p < 0.05) in case of the invasive S. inaequidens. More pronounced changes were detected for the overall nematode community density, and, more specifically, for the bacterivorous genus Anaplectus and the family Monhysteridae (both p < 0.05), as well as the necromenic Pristionchus (p < 0.001). At high taxonomic level, no differences were observed in fungal rhizosphere communities between native and non‐native ragwort species. The impact of plant developmental stages on rhizosphere biota was prominent. The overall bacterial and fungal biomasses, as well as a remarkably consistent set of constituents (Actinobacteria, α‐ and β‐Proteobacteria and Bacteroidetes) were negatively affected by plant stage for both ragwort species. Although later developmental stages of plants generally coincided with lower levels for individual nematode taxa, densities of the fungivorous genera Diphtherophora and Tylolaimophorus remain unaltered. Hence, even at a high taxonomic level, differential effects of native and non‐native ragwort could be pinpointed. However, plant developmental stage has a more prominent impact and this impact was similar in nature for both native and non‐native ragwort species.