Global biodiversity gradients are generally expected to reflect greater species replacement closer to the equator. However, empirical validation of global biodiversity gradients largely relies on vertebrates, plants, and other less diverse taxa. Here we assess the temporal and spatial dynamics of global arthropod biodiversity dynamics using a beta-diversity framework. Sampling includes 129 sampling sites whereby malaise traps are deployed to monitor temporal changes in arthropod communities. Overall, we encountered more than 150,000 unique barcode index numbers (BINs) (i.e. species proxies). We assess between site differences in community diversity using beta-diversity and the partitioned components of species replacement and richness difference. Global total beta-diversity (dissimilarity) increases with decreasing latitude, greater spatial distance and greater temporal distance. Species replacement and richness difference patterns vary across biogeographic regions. Our findings support long-standing, general expectations of global biodiversity patterns. However, we also show that the underlying processes driving patterns may be regionally linked.

The restoration of arid landscapes impacted by historical overgrazing can be complex and may require active, multifaceted interventions, particularly where an ecosystem has shifted to an alternate state. Woody debris is naturally present in many ecosystems, enhancing ecosystem function, and its addition is used as a restoration intervention in overgrazed landscapes to restore ecological function. We applied 13,500 m2 of structurally complex coarse woody debris made up of leaves, branches, and twigs (known as “branching”) across 15 sites within three different vegetation communities of varying degradation (erosion scalds, chenopod shrublands, and black box woodlands) in a semiarid floodplain in southern Australia. Using a Before/After, Control/Impact design, we quantified the impact of branching on vegetation cover and composition and small reptile and mammal abundance and richness for 4 years after treatment application. We found that branching facilitated the recovery of vegetation, most effectively on erosion scalds, the most degraded vegetation community, with a 20% increase in cover and more than triple the plant species richness. In black box woodlands, plant species richness more than doubled in branched plots. Reptile abundance and richness increased in branched plots but only 4 years after application, and mammals were not strongly associated with the addition of woody debris. Our study provides experimental evidence for the use of complex woody debris as a multipurpose restoration tool to facilitate vegetation recovery and provide habitat for small vertebrates. This technique is effective in drylands, where active restoration interventions are risky and prone to failure.

Desert ecosystems are characterised by a patchy distribution of resources. Nutrient sinks associated with landscape modulators (trees) differ markedly from the resource‐poor interpatch matrix. Fauna can also act as landscape modulators, modifying patch dynamics by redistributing resources via ‘ecosystem engineering’. In semi‐arid woodlands, malleefowl ( Leipoa ocellata : Megapodiidae) reconfigure surface characteristics by scavenging leaf litter to construct large incubation mounds. The extent to which this movement of resources creates a novel patch and alters extant patches is largely unknown. Ecosystem engineering effects by megapodes have been little studied, but are potentially great, particularly in drylands, where mammalian engineers are known to enhance ecosystem function and drive restoration. We measured vegetation, ground cover and soil chemistry at malleefowl mounds and four extant microsites (trees and open areas close to, and far from, mounds) and predicted that: (1) malleefowl mounds would represent enriched, yet novel, microsites; (2) the characteristics of tree and open patches close to the mounds would differ from those away from the mounds, because of the diminishing intensity of disturbance; and (3) effects at tree and open patches close to the mound would be shorter term, compared to the more substantial high‐resource patch formation occurring at the mound, but we expected all effects would diminish with time since malleefowl activity. We found that: (1) malleefowl mounds were novel microsites with soil chemistry more similar to tree‐modulated patches, and groundcover and vegetation variables more similar to the open, interpatch matrix; (2) effects extended to tree and open patches near the mound, but most effects were short lived; and (3) some novel mound attributes (e.g. soil pH, phosphorus, nitrogen, carbon) were greater at mounds, irrespective of their age, while less plant cover and richness on young mounds dissipated with age. Synthesis . Mound‐building megapodes can modulate the distribution of locally derived resources and create a novel microsite. Engineering effects can enhance spatial heterogeneity and ecosystem function over broad spatial and temporal scales, and may assist with ecological restoration, particularly in depauperate, arid systems.

A Correction to this paper has been published: https://doi.org/10.1038/s41597-021-00851-9.

With one million species threatened with extinction and more than a third of terrestrial Earth now devoted to crop or livestock production, many conservation organisations are acquiring land, destocking and converting them to national parks or conservation reserves. When pastoral properties are acquired, destocking is often the first management action. Species responses to destocking are varied and largely associated with changes in ground vegetation complexity. However, studies over short timeframes may fail to capture the often slow and episodic recovery post-destocking, particularly in arid and semi-arid ecosystems. In this study, we examined the response of small mammals and reptiles between 6 and 24 years since destocking in mallee (Eucalytpus sp.) and Casuarina vegetation communities in semi-arid Australia. As casuarina sites were closer to water than mallee, they were subject to higher domestic livestock grazing intensity, and higher grazing pressure from invasive goats and native kangaroos after livestock were removed. We related faunal abundance and diversity to time-sincedestocking, fractional cover, rainfall and temperature and described compositional dynamics. We found that the vegetation types had distinct fauna communities and unique recovery trajectories. In mallee, reptile abundance and diversity increased with time-since-destocking but did not change in casuarina. Small mammal response to time-since-destocking was non-linear and strongly influenced by rainfall. Overall, the mallee community showed signs of recovery, but recovery was less evident in the more degraded casuarina. We highlight that destocking expastoral properties is rarely a restoration `quick-fix' and land managers must deal with a complex legacy of impacts, when converting pastoral land to conservation reserves.

Observations on natural history are a useful but often overlooked branch of ecology. With the use of camera-traps, collection of data e.g. on breeding behaviour and success has never been easier, particularly when studying cryptic species. Additionally, camera-traps are well suited to citizen science because of their ease of operation and the ability to store and verify data. Malleefowl Leipoa ocellata breeding behaviour has previously been studied through direct observation or timelapse photography, resulting in small sample sizes and potentially biased observations. Using camera-trap data collected by citizen scientists, we examined the breeding behaviour of this species. We quantified the timing and duration of mound-tending activities at 20 mounds using camera surveillance for >30,000 hours (1250 days) over six breeding seasons. Time spent at the mound during five mound stages and visit frequencies by the male and female during each stage are reported. Femaleinvolvement at the mound was consistent, although males spent three times as long at the mound compared with females during egg-laying. On egg-laying days, females spent longer uncovering the mound, compared with covering the mound post egg-laying. Our findings confirm that both male and female Malleefowl spend a substantial amount of time constructing and maintaining their mound throughout the year and, most notably, that the female consistently participates in mound-tending.These insights are particularly valuable as our surveillance was over markedly longer time spans than previous studies that relied upon direct observation.

1.Desert ecosystems have sparse and heterogeneous resources. Discrete high-resource patches, associated with landscape modulators such as perennial vegetation, act as nutrient sinks in contrast to open, low-resource areas (interpatch matrix). In semi-arid mallee woodlands, malleefowl (Leipoa ocellata: Megapodiidae) create large incubation mounds by raking leaf litter and soil from high-resource patches to their mound sites in the interpatch matrix. Despite this conspicuous redistribution of resources, nothing is known about the physical and chemical properties of malleefowl mounds. 2.In this study, we measured groundcover, vegetation structure and composition, and soil chemistry at: malleefowl mounds, high-resource microsites modulated by trees, and in the low-resource interpatch matrix. The high and low-resource microsites were sampled near the mound in the potential Malleefowl disturbance zone, and outside of the disturbance zone. Mounds were classified into three age categories based on the number of years since they were active.3.We found that malleefowl mounds were a novel microsite, with soil chemistry more similar to tree-modulated patches and groundcover and vegetation variables more similar to the open, interpatch matrix. Additionally, the novel attributes of the mound persisted beyond 6 years from the last time the mound was active. The effect of malleefowl mound-building activities appeared to extend beyond recently used mounds, with vegetation suppressed in open patches close to the mound.4.Synthesis: Malleefowl redistribute resources from high-resource patches under trees to the open interpatch matrix. Incubation mound-building by animals can be a landscape modulating process via high-resource patch formation and is likely important for ecosystem functioning.

Ecosystem engineers change the availability of resources for other species by forming new habitat or modifying existing habitat but, despite the diversity of avian ecosystem engineers, 80% of current literature focuses on mammals and invertebrates. Malleefowl Leipoa ocellata build large incubation mounds of soil and leaf-litter that are likely to provide habitat for invertebrates and vertebrates but use of their mounds by other vertebrates has never been quantified. Here, we examine vertebrate fauna visitation rates at Malleefowl mounds and non-mounds using camera-trap data collected by two citizen science projects. From 2012 to 2018, 20 active Malleefowl mounds and 16 non-mound sites were monitored over 31,913 hours and 225,144 hours, respectively. In total, we identified visits by 1724 birds, reptiles and mammals from 36 species. The mean number of vertebrate visits per 1000 hours of surveillance was around one and a half times and species richness five times that at mounds compared with non-mounds. Malleefowl mounds may enhance the availability of invertebrate prey for insectivorous birds and mammals, provide a favourable microclimate for reptiles to thermoregulate, and be signalling/social communication locations. Our results show that further research is warranted and suggest that conservation of Malleefowl may be important not only for the Malleefowl itself, but also for a suite of mallee birds and reptiles.

SummaryCoarse woody debris (CWD) has many benefits in restoration, including protecting seedlings from herbivory, and it is often reintroduced where CWD is depauperate. At Calperum Station on the Murray River floodplain, artificially applied CWD (‘branching’) is being trialled to restore erosion scalds. At two erosion scalds, we applied 900 m2 of branching and created a 900 m2 branching‐free control. We predicted that branching would protect seedlings from browsing by mammalian herbivores. We planted Nitre Goosefoot (Chenopodium nitrariaceum) seedlings in each treatment and measured the number of terminal ends affected by herbivory and plant height for 8 weeks. Branching reduced the number of terminal ends affected by herbivory by ~80% and plant height loss by ~60%. Remote cameras detected some browsing by kangaroos, the most abundant herbivores on the Calperum floodplain, although cameras were too few to directly observe much of the browsing that occurred. We did not detect an effect of site browsing pressure on overall herbivory or the effectiveness of the branching. Despite the small sample size, our results suggest that branching can effectively reduce herbivory. It is likely that the effectiveness of branching in reducing herbivory is conditional on a range of factors, such as browsing pressure (i.e. scat density), so a large‐scale trial is required to clarify the role branching has on reducing herbivory in relation to these complex interactions.

1. Plant species show considerable leaf trait variability that should be accounted for in dynamic global vegetation models (DGVMs). In particular, differences in the acclimation of leaf traits during periods more and less favourable to growth have rarely been examined. 2. We conducted a field study of leaf trait variation at seven sites spanning a range of climates and latitudes across the Australian continent; 80 native plant species were included. We measured key traits associated with leaf structure, chemistry and metabolism during the favourable and unfavourable growing seasons. 3. Leaf traits differed widely in the degree of seasonal variation displayed. Leaf mass per unit area (M-a) showed none. At the other extreme, seasonal variation accounted for nearly a third of total variability in dark respiration (R-dark). 4. At the non-tropical sites, carboxylation capacity (V-cmax) at the prevailing growth temperature was typically higher in summer than in winter. When V-cmax was normalized to a common reference temperature (25 degrees C), however, the opposite pattern was observed for about 30% of the species. This suggests that metabolic acclimation is possible, but far from universal. 5. Intraspecific variationcombining measurements of individual plants repeated at contrasting seasons, different leaves from the same individual, and multiple conspecific plants at a given sitedominated total variation for leaf metabolic traits V-cmax and R-dark. By contrast, site location was the major source of variation (53%) for M-a. Interspecific trait variation ranged from only 13% of total variation for V-cmax up to 43% for nitrogen content per unit leaf area. 6. These findings do not support a common practice in DGVMs of assigning fixed leaf trait values to plant functional types. Trait-based models should allow for interspecific differences, together with spatial and temporal plasticity in leaf structural, chemical and metabolic traits.

The ratio of leaf intercellular to ambient CO2 (χ) is modulated by stomatal conductance (gs ). These quantities link carbon (C) assimilation with transpiration, and along with photosynthetic capacities (Vcmax and Jmax ) are required to model terrestrial C uptake. We use optimization criteria based on the growth environment to generate predicted values of photosynthetic and water-use efficiency traits and test these against a unique dataset. Leaf gas-exchange parameters and carbon isotope discrimination were analysed in relation to local climate across a continental network of study sites. Sun-exposed leaves of 50 species at seven sites were measured in contrasting seasons. Values of χ predicted from growth temperature and vapour pressure deficit were closely correlated to ratios derived from C isotope (δ13 C) measurements. Correlations were stronger in the growing season. Predicted values of photosynthetic traits, including carboxylation capacity (Vcmax ), derived from δ13 C, growth temperature and solar radiation, showed meaningful agreement with inferred values derived from gas-exchange measurements. Between-site differences in water-use efficiency were, however, only weakly linked to the plant's growth environment and did not show seasonal variation. These results support the general hypothesis that many key parameters required by Earth system models are adaptive and predictable from plants' growth environments.

Abstract. Estimation of the basal or heterotrophic soil respiration is crucial for determination of whether an ecosystem is emitting or sequestering carbon. A severe bushfire in January 2014 at the Calperum flux tower, operational since August 2010, provided variation in ecosystem respiration and leaf area index as the ecosystem recovered. We propose ecosystem respiration is a function of leaf area index and the y-intercept is an estimate of heterotrophic soil respiration. We calculated an assimilation rate from eddy covariance data for light response functions to calculate ecosystem respiration incorporating suppression of the daytime autotrophic respiration. Ecosystem respiration from light response functions correlated with data processing calculations of ecosystem respiration by OzFluxQC (y0 = 0.161x + 0.0085; Adj. r2 = 0.698). The relationship between ecosystem respiration and leaf area index (y0 = 1.43x +0.398; Adj. r2 = 0.395) was also apparent. When this approach was compared to field measurements of soil respiration and mass balance calculations from destructive leaf area, leaf area index calculations and litter fall, the year of data corresponding to the year of soil respiration measurements, the y-intercept was 0.432 µmol m−2 s−1 or 163.44 gC m−2 year−1 (y0 = 1.37x + 0.432, Adj. r2 = 0.325). The mass balance approach for the net primary productivity when subtracted from the tower NEE estimated heterotrophic soil respiration of 134.59 gC m−2 year−1. This is only 28.9 gC different, therefore the y-intercept approach indeed provides an estimate of heterotrophic soil respiration.