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First-year seedlings (FYS) of tree species may be a critical demographic bottleneck in semi-arid, seasonally dry ecosystems such as savannas. Given the highly variable water availability and potentially strong FYS-grass competition for water, FYS water-use strategies may play a crucial role in FYS establishment in savannas and, ultimately, in tree-grass competition and coexistence.We examined drought responses in FYS of two tree species that are dominant on opposite ends of an aridity gradient in Serengeti, Acacia (=Vachellia) tortilis and A. robusta. In a glasshouse experiment, gas exchange and whole-plant hydraulic conductance (KBoth species were strongly anisohydric "water-spenders," allowing rapid wet-season C gain after pulses of moisture availability. Despite being equally vulnerable to declines in KThis work demonstrates an important mechanism of FYS establishment in savannas: Rather than investing in drought tolerance, savanna FYS maximize gas exchange during wet periods at the expense of desiccation during dry seasons. FYS establishment appears dependent on high C uptake during the pulses of water availability that characterize habitats dominated by these species. This study increases our understanding of species-scale plant ecophysiology and ecosystem-scale patterns of tree-grass coexistence.

Acacia longifolia (Sydney golden wattle) is considered one of the most problematic plant invaders in Mediterranean-type ecosystems. In this study, we investigate the species’ invasion history by comparing the genetic diversity and structure of native (Australia) and several invasive range (Brazil, Portugal, South Africa, Spain, and Uruguay) populations and by modelling different introduction scenarios using these data. We sampled 272 A. longifolia individuals – 126 from different invasive ranges and 146 from the native range – from 41 populations. We genotyped all individuals at four chloroplast and 12 nuclear microsatellite markers. From these data we calculated diversity metrics, identified chloroplast haplotypes, and estimated population genetic structure based on Bayesian assignment tests. We used Approximate Bayesian Computation (ABC) models to infer the likely introduction history into each invaded country. In Australia, population genetic structure of A. longifolia appears to be strongly shaped by the Bass Strait and we identified two genetic clusters largely corresponding to mainland Australian and Tasmanian populations. We found invasive populations to represent a mixture of these clusters. Similar levels of genetic diversity were present in native and invasive ranges, indicating that invasive populations did not go through a genetic bottleneck. Bayesian assignment tests and chloroplast haplotype frequencies further suggested a secondary introduction event between South Africa and Portugal. However, ABC analyses could not confidently identify the native source(s) of invasive populations in these two countries, probably due to the known high propagule pressure that accompanied these introductions. ABC analyses identified Tasmania as the likely source of invasive populations in Brazil and Uruguay. A definitive native source for Spanish populations could also not be identified. This study shows that tracing the introduction history of A. longifolia is difficult, most likely because of the complexity associated with the extensive movement of the species around the world. Our findings should be considered when planning management and control efforts, such as biological control, in some invaded regions.

La restauración de los pastizales naturales invadidos por especies vegetales exóticas depende de la composición del banco de semillas del suelo. Se analizó la composición del banco de semillas germinable del suelo en dos ambientes de la Reserva Natural Paititi (Buenos Aires, Argentina): pastizales de Paspalum quadrifarium Lam. (pastizal natural) y pastizales invadidos por árboles exóticos que no superaban los cinco años de edad, Racosperma melanoxylon (R. Br.) Pedley, sinónimo de Acacia melanoxylon (pastizal invadido). Se tomaron muestras de suelo de cada ambiente en tres sitios, y mediante el registro de la emergencia de plántulas bajo condiciones controladas se determinó: 1) la densidad del banco de semillas total y de los grupos funcionales (dicotiledóneas, gramíneas y graminoides), la riqueza, la equitatividad, la diversidad y la abundancia específica, 2) la disimilitud florística, y 3) el valor zootécnico. Ni el banco de semillas de las especies nativas ni el de las exóticas difirieron significativamente entre ambientes. La densidad promedio del banco de semillas y de la riqueza no fueron significativamente diferentes entre ambientes (~10000 semillas/m2 y 30 especies, respectivamente). El número de semillas de los grupos funcionales y los índices de diversidad y de equitatividad tampoco fueron significativamente diferentes entre ambientes. Sin embargo, la disimilitud florística fue 0.36 y se explica por la ausencia de un mayor número de especies en el pastizal invadido, entre ellas, las buenas forrajeras. Esto determinó un valor zootécnico 26% menor en el pastizal invadido que en el natural. En el pastizal invadido, todas las plantas de P. quadrifarium estaban muertas y su banco de semillas germinable fue casi un tercio que en el pastizal natural. Estos resultados permiten considerar que si se eliminan los árboles de R. melanoxylon del pastizal recientemente invadido se podría conservar un banco de semillas comparable al del pastizal natural. The restoration of natural grasslands invaded by exotic plant species depends on the composition of the soil seed bank. We analyzed the composition of germinable soil seed bank in two environments of the Paititi Natural Reserve (Buenos Aires, Argentina): Paspalum quadrifarium Lam. grasslands (natural grassland) and grasslands invaded by species of exotic trees that were no more than five years old, Racosperma melanoxylon (R. Br.) Pedley, synonymous Acacia melanoxylon (invaded grassland). Soil samples from each environment were taken at three sites, and by recording seedling emergence under controlled conditions we determined: 1) the total soil seed bank density of the functional groups (dicots, grasses and graminoids), richness, equitability and diversity indices, and specific abundance, 2) floristic dissimilarity, and 3) zootechnical value. The seed bank of native and exotic species was not significantly different between environments. Average seed bank density and species richness were not significantly different between environments (~10000 seeds/m² and 30 species, respectively). Seed density of the functional groups and the diversity and equitability indices were not significantly different between environments. Still, floristic dissimilarity among environments was as low as 0.36, explained by the absence of a greater number of species in the invaded grassland. The seed bank of invaded grasslands was poor in forage species, consistent with a zootechnical value 26% lower than in the natural grassland. In the invaded grassland all P. quadrifarium plants were dead and their germinable seed bank was a third than in the natural grassland. The results suggest that an early intervention removing R. melanoxylon trees in the grassland invaded may preserve a soil seed bank comparable to those uninvaded grassland. EEA Balcarce Fil: Vignolio, Osvaldo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Fil: Garavano, María Eugenia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Fil: Diez de Ulzurrun, Patricia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Fil: Angelini, Hernán Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Fil: Ispizúa, Verónica. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.

The diaspores of Lepidosperma Labill. (Cyperaceae) have thickened perianth members persistent at the base of the fruit, which are generally assumed to form a unique type of elaiosome but this assumption has not been tested rigorously. We tested whether the perianth provides a lipid-rich food reward and improves diaspore removal by ants in three species of Lepidosperma. We measured (i) the lipid and fatty acid composition of the fruit and perianth of two species of Lepidosperma, and of the seed and aril of two species of Acacia (known myrmecochores), (ii) the relative attractiveness to ants of the perianth in three species of Lepidosperma, and (iii) the relative attractiveness to ants of the diaspores of the same species of Lepidosperma compared with the two species of Acacia. We found that (i) Lepidosperma diaspores show traits consistent with myrmecochory, particularly the high lipid content (∼12–60%) and fatty acid profile of perianth material, (ii) isolated perianth members were removed in greater numbers over all times than were diaspores only (i.e. with perianth removed) in two species of Lepidosperma (n = 100, P = 0.035 and 0.047), whereas the difference was equivocal in the third species (n = 100, P > 0.05), and (iii) Lepidosperma and Acacia diaspores were removed in similar numbers over time (n = 100, P > 0.5). Seven species of diaspore-removing ant were observed, with Rhytidoponera metallica accounting for ∼50% of observed removals. We conclude that the perianth members of Lepidosperma are an elaiosome that provides a lipid-rich food reward.

The xylophagous beetle, Steraspis speciosa, has infected Acacia forests in Saudi Arabia, causing significant damage and even leading to the death of several trees. In the Ha’il region, in the north of Saudi Arabia, an investigation of 13 study sites shows that the Acacia population is mainly composed of three species: A. gerrardii (90.3%), A. ehrenbergiana (7.5%), and A. raddiana (2.2%) and that 21.7% of this population was infected by S. speciosa. The age of the tree (young, adult, old) and environment habitat (Dam, Wadi, Plateau) effects, and insect life-cycle were studied in the protected Machar National Park. Infection in the park, estimated at 25.4%, mainly affects the oldest trees (20.1%) more than the youngest ones (2.3%), while the driest environments (Plateau, 38.8%) are more vulnerable to infection than humid habitats (Dam, 9.4%). The life cycle of S. speciosa lasts about two years, with four stages to complete metamorphosis: mating and eggs (≈3 months), larvae (≈16 months), pupae (≈3 months), and emergency and adults (≈3 months). The larvae stage with many metamorphic instars was the most harmful for tree and takes the longest. The female beetle lays its eggs on weak stem parts. Steraspis speciosa larvae feed on the stems of Acacia trees, and the instar larvae were gathered under the bark of infected stems, harming most of the phloem and a large portion of the xylem. When combined with a prolonged period of drought, S. speciosa causes the withering of numerous branches and, in extreme cases, kills the entire tree.

Cooperative interactions may frequently be reinforced by "partner fidelity feedback," in which high- or low-quality partners drive positive feedbacks with high or low benefits for the host, respectively. Benefits of plant-animal mutualisms for plants have been quantified almost universally in terms of growth or reproduction, but these are only two of many sinks to which a host-plant allocates its resources. By investigating how partners to host-plants impact two fundamental plant resources, carbon and water, we can better characterize plant-partner fidelity and understand how plant-partner mutualisms may be modulated by resource dynamics. In Laikipia, Kenya, four ant species compete for Acacia drepanolobium host-plants. These ants differ in multiple traits, from nectar consumption to host-plant protection. Using a 5-year ant removal experiment, we compared carbon fixation, leaf water status, and stem non-structural carbohydrate concentrations for adult ant-plants with and without ant partners. Removal treatments showed that the ants differentially mediate tree carbon and/or water resources. All three ant species known to be aggressive against herbivores were linked to benefits for host-plant resources, but only the two species that defend but do not prune the host, Crematogaster mimosae and Tetraponera penzigi, increased tree carbon fixation. Of these two species, only the nectivore C. mimosae increased tree simple sugars. Crematogaster nigriceps, which defends the tree but also castrates flowers and prunes meristems, was linked only to lower tree water stress approximated by pre-dawn leaf water potential. In contrast to those defensive ants, Crematogaster sjostedti, a poor defender that displaces other ants, was linked to lower tree carbon fixation. Comparing the effects of the four ant species across control trees suggests that differential ant occupancy drives substantial differences in carbon and water supply among host trees. Our results highlight that ant partners can positively or negatively impact carbon and/or water relations for their host-plant, and we discuss the likelihood that carbon- and water-related partner fidelity feedback loops occur across ant-plant mutualisms.

Species of the genus Acacia have been introduced worldwide and have negative environmental and socio-economic impacts in many introduced regions. This study makes use of environmental and socio-economic impact classification schemes for alien taxa (EICAT and SEICAT) to assess the impacts that 33 acacias introduced to South Africa have at a global scale. The aims of this study were: (1) to compare the EICAT impact categories which are based on literature with expert assessments; (2) to determine which environmental and socio-economic mechanisms underlie acacia impacts; and (3) to test if certain habitats experience higher impact magnitudes than others. Most acacias had a massive impact when evaluated by experts, while the impact was mostly major for EICAT. This could be due to the use of different definitions for the impact categories. It might also show that the data available is insufficient or inadequate in showing that such high impacts exist. Competition was found to be the most often recorded mechanism underlying acacia environmental impacts and was one of the mechanisms with the largest impact magnitude. Grassland, shrubland, marine-coastal and forest habitats were found to be impacted by acacias equally as much. Using impact scoring schemes as an evidence-based and transparent approach to determine the impact status of alien species provides a more robust method to aid management prioritisation and risk assessment than expert opinion alone. However, data quality and availability could limit their effectiveness, especially for less well studied species.

Comments are presented on an article published in October 2020 in Ecology and Evolution (“Predictive ability of a process‐based versus a correlative species distribution model”) by Higgins et al. This analyzed natural distributions of Australian eucalypt and acacia species and assessed the adventive range of selected species outside Australia. Unfortunately, inappropriate variables were used with the MaxEnt species distribution model outside Australia, so that large climatically suitable areas in the Northern Hemisphere were not identified. Examples from a previous analysis and from the use of the freely available spatial portal of the Atlas of Living Australia are provided to illustrate how the problem can be overcome. The comparison of methods described in the Higgins et al. paper is worthwhile, and it is hoped that the authors will be able to repeat their analyses using appropriate variables with the correlative model., The Higgins et al., (2020) MaxEnt species distribution modeling analysis used inappropriate variables outside Australia. As a result, large climatically suitable areas for Acacia saligna in the Northern Hemisphere, especially in the Mediterranean Basin, were not identified

Non-native nitrogen-fixing Acacia species have been invading riparian ecosystems worldwide, potentially threatening stream communities that strongly depend on allochthonous litter. We examined the effects of the invasion of native deciduous temperate forests by Acacia species on litter decomposition and associated fungal decomposers in streams. Litter of native (Alnus glutinosa and Quercus robur) and invasive (Acacia melanoxylon) species were enclosed in fine-mesh bags and immersed in three native and three invaded streams, for 14–98 days. Litter decomposition rates, fungal biomass, and aquatic hyphomycete sporulation rates were higher in invaded than in native streams, likely due to the higher water nitrogen concentration found in invaded streams. Alnus glutinosa litter had higher aquatic hyphomycete sporulation rates and species richness, and higher decomposition rates, probably because they were soft and nitrogen rich. Quercus robur litter also had high aquatic hyphomycete sporulation rates but lower decomposition rates than Al. glutinosa, probably due to high polyphenol concentration and carbon:nitrogen ratio. Acacia melanoxylon litter had lower aquatic hyphomycete sporulation rates and species richness, and lower decomposition rates, most likely because it was very tough. Thus, litter decomposition rates varied in the order: Al. glutinosa > Q. robur > Ac. melanoxylon. The aquatic hyphomycete community structure strongly differed between native and invaded streams, and among litter species, suggesting that microbes were sensitive to water nitrogen concentration and litter characteristics. Overall, increases in water nitrogen concentration and alterations in litter characteristics promoted by the invasion of native riparian forests by Acacia species may affect the activity and community structure of microbial decomposers, and instream litter decomposition, thus altering the functioning of stream ecosystems.

The secondary range of the mesquite, or Prosopis juliflora (Sw.) DC. (Mimosaceae or Fabaceae s.l.) in Fujairah, United Arab Emirates (UAE), is analyzed. The features of its distribution, seed germination, and early stages of seedling development are studied. Mesquite appeared on the territory of the Emirates in the 20th century: one of the first herbarium collections was dated 1983. In the secondary range, it is most often found in anthropogenic habitats: in gardens, along fences, near roads, on wastelands, less often on the streets, etc. P. juliflora successfully naturalizes and creates stable self-reproducing populations. It possesses a complex of specific helio-mesomorphic structural features, which allows it to successfully take root in relatively open, moderately humid and even dry or saline habitats and to compete with native species of acasia (Acacia tortilis, A. ehrenbergii) and Prosopis cineraria. Features such as high germination of seeds and significant morphological, dimensional, and temporal variability of premature individuals of P. juliflora identified in this study undoubtedly contribute to the successful naturalization of the species in the secondary range and its wide distribution throughout the emirates. Owing to the high aggressiveness of mesquite, it is necessary to develop a methodology for combating this plant in the UAE, which will stop its uncontrolled settlement in the region. A map of the distribution of the species in Fujairah and the surrounding areas has been compiled, clearly showing the scale of the disaster. A method for assessing the invasion on a five-point scale, based on the reproductive success of the species, has been developed and applied. The structure of ecotopes at the early stages of the invasion of P. juliflora was analyzed on large wastelands (2 and 1.2 ha) in the settlements of Mirbah and Fujairah on the coast of the Gulf of Oman.

Invasive ants shape assemblages and interactions of native species, but their effect on fundamental ecological processes is poorly understood. In East Africa, Pheidole megacephala ants have invaded monodominant stands of the ant-tree Acacia drepanolobium, extirpating native ant defenders and rendering trees vulnerable to canopy damage by vertebrate herbivores. We used experiments and observations to quantify direct and interactive effects of invasive ants and large herbivores on A. drepanolobium photosynthesis over a 2-year period. Trees that had been invaded for ≥ 5 years exhibited 69% lower whole-tree photosynthesis during key growing seasons, resulting from interaction between invasive ants and vertebrate herbivores that caused leaf- and canopy-level photosynthesis declines. We also surveyed trees shortly before and after invasion, finding that recent invasion induced only minor changes in leaf physiology. Our results from individual trees likely scale up, highlighting the potential of invasive species to alter ecosystem-level carbon fixation and other biogeochemical cycles.

Aboveground litter inputs and root exudates provide basal resources for soil communities, however, their relative contributions to soil food web are still not well understood. Here, we conducted a field manipulative experiment to differentiate the effects of litter inputs and living root on nematode community composition of surface and subsoils in a young Acacia crassicapa plantation in southern China. Our results showed that both litter addition and root presence significantly enhanced soil nematode abundance by 17.3% and 35.3%, respectively. Litter addition altered nematode trophic group composition, decreased fungivore to bacterivore ratio, and enhanced maturity index and structure index, which led to a bacterial-based energy channel and a more complex food web structure. However, root presence had a limited impact on the nematode community composition and ecological indices. Despite nematodes surface assembly, soil depth did not affect nematode trophic group composition or ecological index. Our findings highlight the importance of litter inputs in shaping soil nematode community structure and regulating soil energy channel.

While kikuyu (Cenchrus clandestinus) is an important grass for dairy and beef production in the subtropical region of Australia and the world, the most common cultivar, Whittet, is seriously affected by the fungal diseases, kikuyu yellows (Verrucalvus flavofaciens) and black spot (Bipolaris spp.). Thus resistance to these diseases is a priority in selecting a better kikuyu cultivar, along with higher herbage quality and yield and better winter growth. A study was conducted to identify suitable candidates from kikuyu ecotypes collected along the east coast of Australia plus lines obtained by subjecting Whittet to a mutagenic agent. Initial glasshouse studies identified 19 lines that were resistant to the KY1A strain of kikuyu yellows and 4 of these, with forage quality and yield superior to Whittet, were further evaluated in the field at 2 sites using Whittet as the control. At Site 1, line 12A demonstrated a much higher level of resistance to kikuyu yellows than Whittet, with 85% of plants resisting infection compared with only 15% of Whittet plants. At Site 2, the numbers of 12A and Whittet plants infected were similar. Further tests, using kikuyu yellows inoculum collected from 11 sites along the east coast of Australia, found that only 15% of 12A plants became infected compared with 61% of Whittet plants. Thus, kikuyu line 12A was resistant to most, but not all, strains of the kikuyu yellows pathogen. Annual yield of 12A (19,008 kg DM/ha) was 24% higher than that of Whittet and 12% higher than Acacia, but the difference was significant only for Whittet. During summer, 12A produced 10,212 kg DM/ha (24% higher than Whittet), was more active in early spring, had slightly higher dry organic matter digestibility (66.7 vs. 64.0%) and was resistant to black spot infection.

Invasive plants often impact soil conditions, notably through changes in soil chemistry and microbial community composition, potentially leading to altered soil functionality. We determine the impacts of invasive nitrogen-fixing Australian Acacia trees on soil chemistry and function (carbon, nitrogen, and phosphorus cycling) in South Africa's Core Cape Subregion, and whether any differences in soil function are linked to differences in soil chemical properties and bacterial community composition between neighbouring acacia-invaded and uninvaded sites. We do so by using Illumina MiSeq sequencing data together with soil chemistry and soil enzyme activity profiles. Acacias significantly increased levels of soil nitrogen (NO3-, NH4+, and total N), C, and pH. Although we did not find evidence that acacias affected soil bacterial community diversity, we did find them to alter bacterial community composition. Acacias also significantly elevated microbial phosphatase activity, but not β-glucosidase, whilst having contrasting effects on urease. Changes in soil chemical properties under acacia invasion were found to correlate with changes in enzyme activities for urease and phosphatase. Similarly, changes in soil bacterial community composition were correlated to changes in phosphatase enzymatic activity levels under acacia invasion. Whilst we found evidence for acacias altering soil function by changing soil chemical properties and bacterial community composition, these impacts appear to be specific to local site conditions.

Supercolonial ants are among the largest cooperative units in nature, attaining extremely high densities. How these densities feed back into their population growth rates and how abundance and extrinsic factors interact to affect their population dynamics remain open questions. We studied how local worker abundance and extrinsic factors (rain, tree density) affect population growth rate and spread in the invasive big-headed ant, which is disrupting a keystone mutualism between acacia trees and native ants in parts of East Africa. We measured temporal changes in big-headed ant (BHA) abundance and rates of spread over 20 months along eight transects, extending from areas behind the front with high BHA abundances to areas at the invasion front with low BHA abundances. We used models that account for negative density dependence and incorporated extrinsic factors to determine what variables best explain variation in local population growth rates. Population growth rates declined with abundance, however, the strength of density dependence decreased with abundance. We suggest that weaker density dependence at higher ant abundances may be due to the beneficial effect of cooperative behavior that partially counteracts resource limitation. Rainfall and tree density had minor effects on ant population dynamics. BHA spread near 50 m/year, more than previous studies reported and comparable to rates of spread of other supercolonial ants. Although we did not detect declines in abundance in areas invaded a long time ago (> 10 years), continued monitoring of abundance at invaded sites may help to better understand the widespread collapse of many invasive ants.

Many tree recruitment studies in African savannas target individual factors that limit recruitment, yet recruitment of some species could be limited by an interplay of environmental filters. This study investigated the effects of land use and microsite availability on early seedling recruitment of Acacia tortilis in riverine woodlands in north-western Zimbabwe. The riverine woodlands were divided according to the level of human disturbance into protected and unprotected sites. Each site was further divided into riverine and off riverine microsites. In each microsite, we laid five main plots (100 × 50 m) and nine seedling subplots (5 × 5 m) nested in each main plot, making a total of 60 main plots and 180 subplots. We found higher seedling recruitment in unprotected than protected sites. Although seeder density was twice greater in protected than unprotected sites, seed bank density was lower in the former by a factor of 1.5. Tree cover and herbaceous biomass was 1.4 and 1.8 times greater in protected than unprotected sites, respectively but were negatively correlated with seedling density. Across all microsites, herbivory-related mortality was less than 40% while drought-related mortality was more than 60%. Put together, the results suggest that higher recruitment in unprotected sites was most likely facilitated by domestic ungulates through seed dispersal and grass suppression which enhanced the quality of regeneration sites. We conclude that encroachment of A. tortilis in communal grazing sites is not only important for its conservation but for a variety of goods and services derived from it.

Acacia mangium plantations account for more than 50 % of the exotic plantations in Vietnam. A new black butt symptom was discovered in 2012, followed by the wilting sign in Acacia seedlings in Tuyen Quang Province. Isolations recovered two Phytophthora species, the well-known Acacia pathogen P. cinnamomi, and an unknown species. The new species is described here as Phytophthora acaciivora sp. nov. Phylogenetically this species resides in clade 2d and is most closely related to P. frigida. Phytophthora acaciivora is a heterothallic species, oospores are aplerotic and antheridia are amphigynous. It produces predominantly elongated ovoid, semi papillate, persistent sporangia, no hyphal swellings and no chlamydospores. Optimum temperature for the growth is 25–30 °C and the maximum temperature is over 37.5 °C. Studies are underway to determine the impact of this new species on Acacia plantations in Vietnam.

Aims In plant eco-physiology, less negative (enriched) carbon 13 (13C) in the leaves indicates conditions of reducing leaf gas exchange through stomata, e.g. under drought. In addition, 13C is expected to be less negative in non-photosynthetic tissues as compared with leaves. However, these relationships in δ 13C from leaves (photosynthetic organs) to branches, stems and roots (non-photosynthetic organs) are rarely tested across multiple closely related tree species, multiple compartments, or in trees growing under extreme heat and drought. Methods We measured leaf-to-root 13C in three closely related desert acacia species (Acacia tortilis, A. raddiana and A. pachyceras). We measured δ 13C in leaf tissues from mature trees in southern Israel. In parallel, a 7-year irrigation experiment with 0.5, 1.0 or 4.0 L day−1 was conducted in an experimental orchard. At the end of the experiment, growth parameters and δ 13C were measured in leaves, branches, stems and roots. Important Findings The δ 13C in leaf tissues sampled from mature trees was ca. −27‰, far more depleted than expected from a desert tree growing in one of the Earth’s driest and hottest environments. Across acacia species and compartments, δ 13C was not enriched at all irrigation levels (−28‰ to ca. −27‰), confirming our measurements in the mature trees. Among compartments, leaf δ 13C was unexpectedly similar to branch and root δ 13C, and surprisingly, even less negative than stem δ 13C. The highly depleted leaf δ 13C suggests that these trees have high stomatal gas exchange, despite growing in extremely dry habitats. The lack of δ 13C enrichment in non-photosynthetic tissues might be related to the seasonal coupling of growth of leaves and heterotrophic tissues.

In Malaysia, the current status of birds inhabiting agarwood Aquilaria malaccensis plantations has not been specifically studied, and little research has been conducted to investigate birds in other agricultural areas (e.g., rubber, acacia, and oil palm plantations) and disturbed areas. This study was conducted to assess bird species richness and relative abundance, as well as feeding guilds, in two agarwood plantation sites: Universiti Pendidikan Sultan Idris in Tanjong Malim (UPSI), and Slim River (SR). The presence of birds was recorded using a combination of techniques (mist-nets and point count), while various sources were used to compile feeding information. This study recorded 364 birds from 36 species in 24 families. Shannon diversity index (H’) values for the UPSI and SR sites were 2.896 and 2.492 respectively, indicating high bird diversity. The Bray-Curtis index was 0.29, indicating these sites share few species. Insectivorous and omnivorous birds were dominant in UPSI (31%), and omnivores at SR (32%). The commonest insect order at both sites was Orthoptera (UPSI 48%, SR 25%). While agarwood plantations are relatively homogeneous, they provide a variety of food sources and shelter for a wide range of birds.

Across the globe, biological invasions have disrupted mutualisms, producing reverberating consequences for ecosystems. Although invasive species frequently trigger mutualism disruptions, few studies have quantified the demographic mechanisms by which mutualism breakdown may generate population effects. In a Kenyan savanna, the invasive big-headed ant (Pheidole megacephala) has disrupted a foundational mutualism between the monodominant whistling-thorn tree (Acacia drepanolobium) and native ants (Crematogaster spp.) that deter browsing by large mammalian herbivores. We conducted experiments to quantify the demographic consequences of this mutualism disruption in the presence and absence of large mammalian herbivores. Invasion by P. megacephala exacerbated population declines of A. drepanolobium, primarily through decreased survival and reproduction of adult trees. However, these fitness reductions were small compared to those resulting from the presence of large mammalian herbivores, which negatively impacted growth and survival. Contrary to expectation, the expulsion of metabolically costly Crematogaster mutualists by P. megacephala did not result in higher population growth rates for trees protected from large mammalian herbivores. Our results suggest that invasive P. megacephala may impose a direct metabolic cost to trees exceeding that of native mutualists while providing no protection from browsing by large mammalian herbivores. Across landscapes, we expect that invasion by P. megacephala will reduce A. drepanolobium populations, but that the magnitude and demographic pathways of this effect will hinge on the presence and abundance of browsers.

Fire is a major selective force on arid grassland communities, favoring traits such as the smoke‐induced seed germination response seen in a wide variety of plant species. However, little is known about the relevance of smoke as a cue for plants beyond the seedling stage. We exposed a fire‐adapted savanna tree, Vachellia (=Acacia) drepanolobium, to smoke and compared nutrient concentrations in leaf and root tissues to unexposed controls. Experiments were performed on three age cohorts: 2‐year‐old, 9‐month‐old, and 3‐month‐old plants. For the 2‐year‐old plants exposed to smoke, carbon and nitrogen concentrations were lower in the leaves and higher in the roots than controls. Less pronounced trends were found for boron and magnesium. In contrast, smoke‐exposed 3‐month‐old plants had lower root nitrogen concentrations than controls. No significant differences were found in the 9‐month‐old plants, and no significant shifts in other nutrient concentrations were observed between plant tissues for any of the three age cohorts. Synthesis: Our findings are consistent with smoke‐induced translocation of nutrients from leaves to roots in 2‐year‐old V. drepanolobium. This could represent a novel form of fire adaptation, with variation over the course of plant development. The translocation differences between age cohorts highlight the need to investigate smoke response in older plants of other species. Accounting for this adaptation could better inform our understanding of savanna community structure and nutrient flows under fire regimes altered by anthropogenic land use and climate change.

Quantifying tree biomass is an important research and management goal across many disciplines. For species that exhibit predictable relationships between structural metrics (e.g. diameter, height, crown breadth) and total weight, allometric calculations produce accurate estimates of above-ground biomass. However, such methods may be insufficient where inter-individual variation is large relative to individual biomass and is itself of interest (for example, variation due to herbivory). In an East African savanna bushland, we analysed photographs of small (2 = 0.86 versus R2 = 0.68). When tested on trees in herbivore-exclusion plots versus unfenced (open) plots, our predictive equation based on photos confirmed higher above-ground biomass in the exclusion plots than in unfenced (open) plots (P < 0.001), in contrast to no significant difference based on the allometric equation (P = 0.43). As such, our new technique based on photographs offers an accurate and cost-effective complement to existing methods for tree biomass estimation at small scales with potential application across a wide variety of settings.

The most prolific acacias in southern Europe (Acacia dealbata, A. melanoxylon and A. longifolia) are rapidly spreading in its westernmost area: Portugal and NW Spain, where congeners with invasion potential are already established. We performed a bibliographic search of acacia invasions in southern Europe and used spatial data on acacia distribution and abiotic parameters in Iberia to check the influence of abiotic factors on acacia invasion. According to our results, in Iberia A. dealbata and A. melanoxylon seem limited by high soil pH (pHCaCl2>5.5), frequent frosts (>21 to 40 d yr−1) and low annual precipitation ( to 1000 mm); data were inconclusive for A. longifolia, while A. saligna prefers neutral soils in the driest and warmest areas. The percentage of area occupied by A. dealbata and A. melanoxylon increases significantly with the percentage of burnt surface. In the literature, acacias' invasiveness is usually attributed to their high resprouting and seeding capacity and to native exclusion through their allelopathic potential; symbiotic promiscuity with rhizobia; high environmental plasticity; and adaptation to burnt, cleared and resource-poor land. However, it is unknown how acacias became so invasive in western Iberia, where native Fabaceae shrubs with similar ecological traits (and invaders outside their natural range) are abundant. Invasive acacias can modify fire and water regimes, aboveground biodiversity, and topsoil characteristics (microbial communities, pH, organic matter and macronutrients levels); nevertheless, sound comparisons with mature stands of Iberian legumes for these and other soil properties (N fluxes, micronutrients) are lacking. As several acacias outcompete Iberian Fabaceae shrubs partly thanks to enemy release, the introduction of biocontrol agents (as for A. longifolia in Portugal) can be useful for invasion control.

The invasion of native riparian forests by exotic tree species can lead to profound changes in the ecological integrity of freshwater ecosystems. We assessed litter decomposition of native (Alnus glutinosa and Quercus robur) and invasive (Acacia melanoxylon and Acacia dealbata) tree species, and associated microbial activity and community structure, after being immersed for conditioning in 3 reference and 3 “invaded” streams in Serra da Lousa (central Portugal) and used in microcosms simulating stream conditions. Litter decomposition differed among species, in the order: Al. glutinosa > Q. robur > (Ac. melanoxylon ~ Ac. dealbata). Alnus glutinosa litter decomposed faster probably because it was soft and had high nitrogen concentration for decomposers. Quercus robur litter decomposed slower most likely because it was tough and had high polyphenol and low nitrogen concentrations. Acacia melanoxylon litter was the toughest and had a thick cuticle that likely acted as a physical barrier for microbial colonization. In Ac. dealbata, the small-sized leaflets and high lignin concentration may have limited microbial litter decomposition. Litter decomposition was faster in “invaded” streams, probably because they were N-limited and increases in nitrogen concentration in water, promoted by Acacia species invasion, stimulated microbial activity on litter. The aquatic hyphomycete community structure differed among litter species and between stream types, further suggesting that microbes were sensitive to litter characteristics and water nutrient concentrations. Overall, the invasion of native riparian forests by Acacia species may affect microbial decomposer activity, thus altering important stream ecosystem processes, such as litter decomposition and nutrient cycles.

Three poorly known species of Ravenelia with limited geographic distribution and one widespread species parasitizing leguminous trees (Fabaceae) were newly found in Thailand. Ravenelia odoratissimae occurred on Albizia odoratissima; R. ornata on Abrus pulchellus, Ab. precatorius, and Abrus sp.; R. parasnathii on Acacia comosa and an unidentified Acacia species; and R. tandonii on Acacia catechu. Acacia comosa is a new host for R. parasnathii. Detailed morphological study revealed that R. odoratissimae produces a uredinial stage in addition to a telial stage in its life cycle.

Understanding how tropical tree phenology (i.e., the timing and amount of seed and leaf production) responds to climate is vital for predicting how climate change may alter ecological functioning of tropical forests. We examined the effects of temperature, rainfall, and photosynthetically active radiation (PAR) on seed phenology of four dominant species and community‐level leaf phenology in a montane wet forest on the island of Hawaiʻi using monthly data collected over ~ 6 years. We expected that species phenologies would be better explained by variation in temperature and PAR than rainfall because rainfall at this site is not limiting. The best‐fit model for all four species included temperature, rainfall, and PAR. For three species, including two foundational species of Hawaiian forests (Acacia koa and Metrosideros polymorpha), seed production declined with increasing maximum temperatures and increased with rainfall. Relationships with PAR were the most variable across all four species. Community‐level leaf litterfall decreased with minimum temperatures, increased with rainfall, and showed a peak at PAR of ~ 400 μmol/m2s−1. There was considerable variation in monthly seed and leaf production not explained by climatic factors, and there was some evidence for a mediating effect of daylength. Thus, the impact of future climate change on this forest will depend on how climate change interacts with other factors such as daylength, biotic, and/or evolutionary constraints. Our results nonetheless provide insight into how climate change may affect different species in unique ways with potential consequences for shifts in species distributions and community composition.

Identifying studied sample acacia species selected and collected from Bekele Molla Hotel Avenue, Chamo Kebele, Arba Minch under convenient random sampling method. Tannins extracted using the solvents such as water (at 60 & 900C), methanol (at 900C) and its 1:1 mixture (at 900C) by employing Soxhlet extraction. Extracted crude tannins was separated and purified under vacuum distillation. The photochemical screening and quantitative determinations of sample carried out. Furthermore, the sample of tannins characterized by employing U-visible and FTIR spectroscopic studies. Methonalic extract consist moisture content and % yield about 17.86±0.51 % and 52.55 %. The results of Uv-visible and FTIR spectroscopic studies were supporting that the sample of Acacia xanthophloea has tannins and flavonoids. Thus, this study reveals and confirmed that the methanol is more suitable solvent for extraction of tannins over than water

The Australian genus Reddellomyces comprises several closely related symbiotic ascomycetes with chambered gleba (solid ptychothecium), ornamented ascospores and cylindrical paraphyses that are sometimes difficult to identify based on morphological aspects. Several Reddellomyces species are spread with their Australian host plants (Eucalyptus and Acacia) worldwide including Mediterranean areas. Specimens of an unusual truffle were collected from Acacia saligna stands in Tunisian semi-arid lands and eucalypt forest of Antalya (Turkey) dominated by E. camaldulensis Dehnh. and E. grandis W. Hill. Based on morphological features, these fungi are affiliated to Reddellomyces genus, differing from other species of the genus mainly based on ascospore size. Further analysis based on nuclear rDNA LSU and ITS and digital RFLP of the ITS sequenced amplicons with selected restriction endonucleases showed the unique identity of Tunisian specimens within the genus Reddellomyces. Our results showed also that at least six Reddellomyces species are present including two unnamed species restricted to Australia.

A pen-tailed tree shrew (Ptilocercus lowii) specimen was live-trapped in 2006 in an Acacia plantation for the first known time at Samarakan Planted Forest Zone (PFZ) in Bintulu, Sarawak. However, its lack of recurring in other Acacia plantations suggests that the monoculture agricultural field is not a typical habitat for this species. Live-trapping data suggest that generally there were two breeding seasons per year for this species in Borneo: a more consistent one occurred between February and April, and a broader one between June and October. The second, the broader breeding season likely varied based on the microhabitat of each sampling site. In Samarakan PFZ, during the 2006 season, we recorded one breeding season between September and October, and in 2007 recorded one between June and July. Meanwhile, since the year 2000, this species was recorded at only 17 locations within its range of distribution in Southeast Asia, suggesting the possibility of population decline and shrinkage in its distribution range. Given the rapid disappearance of forested areas in Southeast Asia, stepping up the field studies and targeted sampling for this species becomes the priority task for all of its conservation work.

Plant invasions can modify the composition of native communities through altering diversity and ecosystem functioning. For example, arthropod communities can be influenced by the introduction of invasive plant species, but the impacts of plant invasions on arthropod communities have received little attention. Here, we investigated the diversity and species composition of arthropods in areas with and without invasive plants by comparing native ecosystems and areas invaded by Acacia dealbata, A. longifolia and A. melanoxylon in 18 locations in the northwestern Iberian Peninsula. Yellow sticky traps were placed in branches above ground in randomly selected areas and used to qualify and quantify the number of aerial arthropods. The aim was to assess the impact of invasive Acacia on arthropod species in different ecosystems. Our results demonstrate that arthropods are negatively influenced by Acacia invasions, reducing the abundance and diversity in invaded areas, which had substantial effects on beta-diversity and trophic levels. Overall, our findings indicate that invasive acacias can alter the species composition by not only reducing abundance and diversity but also altering the different trophic groups of the arthropod assemblages. The physical dominance of Acacia invaders alters the co-occurrence of arthropod assemblages, reducing the number of groups and leading to substantial effects on ecosystem dynamics as well as in the trophic diversity. We suggest implementing management strategies to favour the protection of native ecosystems and reduce the impacts of these exotic plants on arthropod biodiversity at the habitat level.

Invasion of alien plant species can alter local plant diversity and ecosystem processes closely linked to soil organic carbon (SOC) and nutrient dynamics. Soil ecosystem processes such as microbial respiration and enzyme activity have been poorly explored under alien plant invasion and especially following invasive plant species removal. We studied the impact of Prosopis juliflora and Acacia mearnsii invasion and subsequent removal on local plant community composition and diversity and on soil microbial respiration and enzyme activity in two biodiversity hotspots in Southern India. Removal of Prosopis promoted recolonisation of local vegetation as indicated by a 38% and 28% increase in species richness and ground vegetation cover, respectively, compared to an unremoved site. Prosopis and Acacia removal led to a significant reduction in soil microbial biomass C (MBC), respiration, dehydrogenase and urease activity due to increased microbial respiration and N mineralisation rate. Higher metabolic quotients qCO2 in soil at Prosopis and Acacia removed sites indicate that MBC pools declined at a faster rate than SOC, resulting decreased MBC/SOC ratios compared to their respective removed sites. Natural and undisturbed ecosystems maintain more SOC through increased belowground and aboveground C input in the soil, resulting in a higher MBC content per unit SOC. Our results indicate that the interaction between above- and below-ground communities is a critical factor determining the structure and dynamics of local plant communities, especially in ecosystems affected by plant invasions.

Dans la région d’El Kala (extrême Nord-Est algérien), Acacia mearnsii De Wild. a été introduit lors des reboisements de 1970, en mélange à 20 % avec l'eucalyptus. Or, depuis quelques décennies, il est constaté un développement de taches d’invasion par cette espèce australienne dans cette même contrée du pays. L’utilisation d’outils tels qu’un système d'information géographique (SIG), avec des informations spatiales à jour, est nécessaire pour mieux comprendre l'invasion et identifier les écosystèmes potentiels à haut risque. Ainsi, le présent travail a été orienté vers la cartographie afin de procéder à l’étude de la répartition de l’invasion de cette espèce. Deux approches ont été adoptées, la première faisant appel aux données collectées sur le terrain et la seconde aux techniques de télédétection, en appliquant la méthode de classification supervisée sur une image Landsat 8. Les résultats obtenus par les deux méthodes montrent que la superficie envahie avoisine les 3 200 ha, répartis en quatre sites. La quasi-totalité de la surface envahie est occupée par l’eucalyptaie et la suberaie (respectivement 65,0 % et 17,9 % de la superficie totale). La classification de l’image satellite n’a permis de détecter que les paysages fortement envahis, tandis que la méthode des relevés effectués sur le terrain a permis de cartographier sa répartition totale. Toutefois, la superposition des deux cartes montre qu’elles sont majoritairement identiques (0,90 ≤ R ≤ 1). Pour conclure, l’utilisation des données spatialisées, couplées à des données ponctuelles (relevés de terrain), a permis, d’une part, de réduire les contraintes liées à la résolution de l’image Landsat et, d’autre part, de montrer l’importance des méthodologies basées sur les travaux de terrain.

The present work represents the first comprehensive taxonomic revision of Acacia sens. lat. (Leguminosae: Mimosoideae) in China, focusing on the indigenous species. Critical reassessments of specimens and re-definition of previously recorded species have resulted in recognising 21 indigenous species under Senegalia, a segregate of the former Acacia sens. lat. Detailed botanical profiles are provided for these species, together with a diagnostic line drawing and distribution map; photographs of living plants are provided for more than half the species. Terser treatments are also provided for the 15 species from four genera that are regarded as major introductions of Acacia sens. lat. to the country: Acacia Mill. (12 spp.), Acaciella Britton & Rose (1 sp.), Senegalia Raf. (1 sp.) and Vachellia Wight & Arn. (1 sp.). An identification key to all Acacia sens. lat. species in China is provided.The indigenous species of Senegalia in China belong to sect. Monacanthea (Vassal) Maslin, comb. nov., and the introduced ones to sect. Senegalia.As a consequence of this study, the number of Senegalia species now recognised for China has almost doubled. Six new species are described: Senegalia clandestina Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.; Senegalia guangdongensis Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.; Senegalia obliqua Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.; Senegalia orientalis Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.; Senegalia prominens Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.; Senegalia stipitata Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov. Four new combinations are established: Senegalia garrettii (I.C.Nielsen) Maslin, B.C.Ho, H.Sun & L.Bai, comb. & stat. nov.; Senegalia kerrii (I.C.Nielsen) Maslin, B.C.Ho, H.Sun & L.Bai, comb. & stat. nov.; Senegalia kunmingensis (C.Chen & H.Sun) Maslin, B.C.Ho, H.Sun & L.Bai, comb. & stat. nov.; Senegalia macrocephala (Lace) Maslin, B.C.Ho, H.Sun & L.Bai, comb. nov. Senegalia andamanica (I.C.Nielsen) Maslin, Seigler & Ebinger and S. macrocephala are new records for China.A lectotype is designated for Acacia teniana Harms and 2nd step lectotypifications effected for Acacia delavayi Franch., Acacia insuavis Lace, Acacia pruinescens Kurz and Acacia yunnanensis Franch. Former holotype citations are corrected to lectotype for Acacia hainanensis Hayata, Acacia macrocephala Lace, Acacia oxyphylla Graham ex Benth. and Acacia philippinarum Benth. A neotype is designated for Acacia arrophula D.Don.China is a principal area of species-richness for Senegalia in Asia. Senegalia displays a high degree of endemism within China and almost half the species are endemic or near-endemic, with Yunnan the most species-rich and species-diverse Province. Abstract: 本研究首次对中国广义相思属 (Acacia sens. lat.) 进行了详细的分类修订, 主要聚焦中国原产物种。通过标本检视和对原记载的物种的进一步探究，本研究确认中国原产21个金合欢属 (Senegalia Raf.) 物种, 该属是广义相思属下分出来的一个属。本文提供了每个原产物种的详细介绍, 以及展现每个物种分类学特征的墨线图以及物种的 分布图，并提供了超过一半的物种的彩色活植物图版。对于中国主要引种栽培的15个广义相思属物种 (其中相思属Acacia Mill. 12种，美洲相思属Acaciella Britton & Rose1种, 金合欢属1种, 鸭皂树属Vachellia Wight 1种) , 本文也作了简要介绍。本文为中国有分布的所有广义相思属的物种提供了一个检索表本研究结果表明中国产金合欢属均属于Monacanthea (Vassal) Maslin组，而外来种属于Senegalia组本研究将中国金合欢属的物种数目几乎翻了一番。发现6个新物种：玉溪金合欢 (Senegalia clandestina Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.) 、广东金合欢 (S. guangdongensis Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.) 、独眼龙 (S. obliqua Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.) 、东方金合欢 (S. orientalis Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.) 、老虎刺金合欢 (S. prominens Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.) 、柄腺金合欢 (S. stipitata Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.) ；成立了4个新组合：盘腺金合欢 (S. garrettii (I.C.Nielsen) Maslin, B.C.Ho, H.Sun & L.Bai, comb. & stat. nov.) 、柯氏金合欢 (S. kerrii (I.C.Nielsen) Maslin, B.C.Ho, H.Sun & L.Bai, comb. & stat. nov.) 、昆明金合欢 (S. kunmingensis (C.Chen & H.Sun) Maslin, B.C.Ho, H.Sun & L.Bai, comb. & stat nov.) ，以及大头金合欢 (S. macrocephala (Lace) Maslin, B.C.Ho, H.Sun & L.Bai, comb. nov.) ；发现2个新记录种：安达曼金合欢 (Senegalia andamanica (I.C.Nielsen) Maslin, Seigler & Ebinger) 和大头金合欢。本文为Acacia teniana Harms指定了后选模式，为A. delavayi Franch., A. insuavis Lace, A. pruinescens Kurz和A. yunnanensis Franch.指定了二次后选模式。前人在A. hainanensis Hayata, A. macrocephala Lace, A. oxyphylla Graham ex Benth. 和A. philippinarum Benth.这4个名称下引用的主模式，被作为错误修正为后选模式，另外，为Acacia arrophula D.Don指定了新模式。本研究表明中国是亚洲金合欢属一个重要的多样性区域，中国该属特有种比例很高，几乎一半的物种为特有 (6种) 或近特有 (4种) ，其中云南省是该属物种最为丰富和多样的省区 Keywords: Acacia, Acaciella, Senegalia, Vachellia, Taxonomy, China

The Novel Weapons Hypothesis postulates that the release of allelochemicals by alien plants can inhibit the growth of evolutionary naive native plants. On the other hand, when species share a recent evolutionary history, recognition of phytochemicals from neighboring plants can have adaptive value by providing cues to signal suitable conditions conducive to establishment. This has been termed the Biochemical Recognition Hypothesis. We explored these two hypotheses by conducting germination experiments in South Africa and Spain and a growth experiment in South Africa, using invasive Australian acacias and native species from each region. The experiments exposed seeds of the selected recipient species to leachates collected under acacias, nearby uninvaded vegetation, or distilled water. We then measured total germination, and above and below ground biomass in the growth experiment. Our results did not support the Novel Weapons Hypothesis, but instead we found some leachates collected under acacias and uninvaded areas to stimulate the germination and early growth of some of our selected acacias and native species. Such effects occurred both at the intra- and interspecific level. In general, interspecific stimulatory effects between invasive acacias occurred irrespective of whether they had overlapping native ranges in Australia. We also found leachates from uninvaded areas in South Africa to have stimulatory effects on one invasive acacia and one native species. Hence, our results support the Biochemical Recognition Hypothesis, suggesting that chemically-induced signals may facilitate acacia establishment in sites that have already been transformed by acacias.

Acacia × mangiiformis Maslin & L.A.J.Thomson, hybrida nova, is described. Its parents are Acacia auriculiformis A.Cunn. ex Benth. and A. mangium Willd., two well-known and important plantation species in Asia and elsewhere. Acacia × mangiiformis arose naturally in the Western Province of Papua New Guinea and in recent decades has become widely cultivated in southeast Asia (Indonesia, Malaysia, Thailand and Vietnam), India, and to a lesser extent in China and Taiwan. The tree has often been referred to as “Acacia hybrid” in forestry literature. Acacia × mangiiformis has morphological and other characteristics that are intermediate between its parents. Furthermore, it often has a faster growth rate, superior bole form and is more drought-tolerant than its parent species The hybrid is used primarily for pulp production but also has uses as solid wood products and fuelwood. The wood is similar to that of A. mangium but has a higher density and is more suitable for products where strength is important; it is also less susceptible to termite attack than are its parent species. Ten high-performing commercial clones of Acacia × mangiiformis have been developed in Vietnam and more are being selected. The formal naming of this important hybrid is dedicated to Professor Le Dinh Kha (formerly of Forest Science Institute of Vietnam), an outstanding researcher, supervisor, and authority on tree breeding who conducted much of the original research and promotion of Acacia × mangiiformis in Vietnam.

Introducción y objetivos El género Acacia (Fabaceae) es de distribución pantropical y actualmente está compuesto por, aproximadamente, 1.450 especies en todo el mundo. En Argentina se pueden encontrar especies pertenecientes a los subgéneros Acacia y Aculeiferum. En este trabajo se estudió la morfología de dos especies, Acacia caven var. caven¸ perteneciente al primer subgénero y Acacia bonariensis, correspondiente al segundo subgénero. El objetivo fue evaluar la variación interespecífica e intraespecífica en base a 12 caracteres exomorfológicos. La hipótesis de trabajo fue que los rasgos utilizados son capaces de diferenciar las especies y las poblaciones. M&M: El estudio se basó en un test de Kruskal Wallis y en diversos análisis con métodos multivariados. Resultados: El test de Kruskal Wallis mostró que nueve caracteres fueron capaces de diferenciar las especies y uno solo las poblaciones. A partir de los análisis multivariados se encontró que, a excepción de un carácter, todos los demás rasgos estudiados resultaron significativos para la diferenciación interespecífica. Conclusiones: Estos resultados evidenciaron una clara separación entre especies de acuerdo a la clasificación taxonómica ya establecida. Sin embargo, no se pudieron establecer diferencias entre los sitios de colección (reservas) para ninguna de las dos especies con estos métodos. En conclusión, estos análisis sientan un precedente para futuros estudios en donde se incluyan más poblaciones naturales y el estudio genético de ésta diferenciación a nivel molecular.

Propolis is a resinous mixture, made by the honeybees from substances collected from tree or other plant buds, plant exudates, or resins found in the stem, branches, or leaves of different plants. The geographical origin of propolis is given by plant sources from respective areas. Different studies have classified this bee product according to the vegetal material from the same areas. Poplar-type propolis has the widest spread in the world, in the temperate zones from Europe, Asia, or North America. The name is given by the main plant source from where the bees are collecting the resins, although other vegetal sources are present in the mentioned areas. Different Pinus spp., Prunus spp., Acacia spp. and also Betula pendula, Aesculus hippocastanum, and Salix alba are important sources of resins for “poplar-type” propolis. The aim of this review is to identify the vegetal material’s chemical composition and activities of plant resins and balms used by the bees to produce poplar-type propolis and to compare it with the final product from similar geographical regions. The relevance of this review is to find the similarities between the chemical composition and properties of plant sources and propolis. The latest determination methods of bioactive compounds from plants and propolis are also reviewed.

Halley, Matthew R. (2021): Lectotypes resolve the taxonomic entanglement of the Acacia Pied Barbet Tricholaema leucomelas (Piciformes: Lybiidae) and Pied Puffbird Notharchus tectus (Piciformes: Bucconidae). Zootaxa 5071 (3): 447-450, DOI: https://doi.org/10.11646/zootaxa.5071.3.10

Lack of proper infrastructure and the poor economic conditions of rural communities make them dependent on herbal medicines. Thus, there is a need to obtain and conserve the historic and traditional knowledge about the medicinal importance of different plants found in different areas of the world. In this regard, a field study was conducted to document the medicinal importance of local plants commonly used by the inhabitants of very old historic villages in Southern Punjab, Pakistan. In total, 58 plant species were explored, which belonged to 28 taxonomic families, as informed by 200 experienced respondents in the study area. The vernacular name, voucher number, plant parts used, and medicinal values were also documented for each species. Among the documented species, Poaceae remained the most predominant family, followed by Solanaceae and Asteraceae. The local communities were dependent on medicinal plants for daily curing of several ailments, including asthma, common cold, sore throat, fever, cardiovascular diseases, and digestive disorders. Among the reported species, leaves and the whole plant remained the most commonly utilized plant parts, while extracts (38.8%) and pastes (23.9%) were the most popular modes of utilization. Based on the ICF value, the highest value was accounted for wound healing (0.87), followed by skincare, nails, hair, and teeth disorders (0.85). The highest RFC value was represented by Acacia nilotica and Triticum aestivum (0.95 each), followed by Azadirachta indica (0.91). The highest UV was represented by Conyza canadensis and Cuscuta reflexa (0.58 each), followed by Xanthium strumarium (0.37). As far as FL was concerned, the highest value was recorded in the case of Azadirachta indica (93.4%) for blood purification and Acacia nilotica (91.1%) for sexual disorders. In conclusion, the local inhabitants primarily focus on medicinal plants for the treatment of different diseases in the very old historic villages of Southern Punjab, Pakistan. Moreover, there were various plants in the study area that have great ethnobotanical potential to treat various diseases, as revealed through different indices.

The biological properties of chilean propolis have been described and include antibacterial, antifungal and antibiofilm activities. Propolis has a strong antimicrobial potential. Clinical experiences with synthetic antibiotics indicated the need to discover new sources of bioactive compounds associated with ethnopharmacological knowledge or natural sources such as propolis. The microscopic analysis of pollen grains from plants allows us to determine the botanical origin of the propolis samples. In Angol, sample pollen grains were obtained from fodder plants (Sorghum bicolor, Lotus sp.) and trees, such as Acacia sp., Pinus radiata, Eucalyptus sp. and Salix babylonica. Propolis from the Maule region contains pollen grains from endemic plants such as Quillaja saponaria. Finally, the sample obtained from Melipilla presented a wider variety of pollen extracted from vegetable species.Colorimetric assays performed to quantify the total polyphenols present in Chilean propolis samples established that PCP2 (Angol sample) showed high amounts of phenolics compounds, with significant statistical differences in comparison with the other samples. The main compounds identified were pinocembrin, quercetin and caffeic acid phenethyl ester (CAPE). The Angol sample showed a high content of polyphenols.Studies that determine the influence of geographical and floral variables on the chemical composition of propolis are a valuable source of information for the study of its biological properties.

Extreme temperatures and scarce precipitation in deserts have led to abiotic factors often being regarded as more important than biotic ones in shaping desert communities. The presumed low biological activity of deserts is also one reason why deserts are often overlooked by conservation programs. We provide the first quantification of predation intensity from a desert ecosystem using artificial sentinel prey emulating caterpillars, a standardized monitoring tool to quantify relative predation pressure by many invertebrate and vertebrate predators. The study was conducted in a protected natural area affected by oil spills in 1975 and 2014; hence, we assessed the potential effects of oil pollution on predation rates. We found that predation was mostly due to invertebrate rather than vertebrate predators, fluctuated throughout the year, was higher at the ground level than in the tree canopy, and was not negatively affected by the oil spills. The mean predation rate per day (12.9%) was within the range found in other ecosystems, suggesting that biotic interactions in deserts ought not to be neglected and that ecologists should adopt standardized tools to track ecological functions and allow for comparisons among ecosystems., Extreme environments such as deserts are expected to have low biodiversity and, therefore, reduced biotic interactions. We addressed this assumption by measuring invertebrate and vertebrate predation rates in a hyper‐arid desert using a standardized monitoring tool that allows recording predator activity in a quantitative, comparable way. We found that the mean predation rate (12.9% per day) is within the range found in other ecosystems, suggesting that this biotic function is no less important in deserts than elsewhere.

For the first time, an updated checklist of Acacia, Senegalia and Vachellia species in Egypt is provided, focusing on the exotic species. Taking into consideration the retypification of genus Acacia ratified at the Melbourne International Botanical Congress (IBC, 2011), a process of reclassification has taken place worldwide in recent years. The review of Acacia and its segregates in Egypt became necessary in light of the available information cited in classical works during the last century. In Egypt, various taxa formerly placed in Acacia s.l., have been transferred to Acacia&nbsp, s.s., Acaciella, Senegalia, Parasenegalia and Vachellia. The present study is a contribution towards clarifying the nomenclatural status of all recorded species of Acacia and its segregate genera. This study recorded 144 taxa (125 species and 19 infraspecific taxa). Only 14 taxa (four species and 10 infraspecific taxa) are indigenous to Egypt (included now under Senegalia and Vachellia). The other 130 taxa had been introduced to Egypt during the last century. Out of the 130 taxa, 79 taxa have been recorded in literature. The focus of this study is the remaining 51 exotic taxa that have been traced as living species in Egyptian gardens or as herbarium specimens in Egyptian herbaria. The studied exotic taxa are accommodated under Acacia s.s. (24 taxa), Senegalia (14 taxa) and Vachellia (13 taxa). Identification keys for the studied genera, generic groups and species have been provided using different taxonomic criteria. For each taxon, the validated name with the first citation followed by relevant Egyptian citations, typification, synonyms, distinctive features, origin, ecology (when available), utilisation and selected specimens are provided. The study revealed the presence of 22 newly recorded taxa in Egypt. Additionally, a list of excluded, unvalidated and unresolved names is given.

Acacia saligna is an invasive alien species that has the ability to establish symbiotic relationships with rhizobia. In the present study, genotypic and symbiotic diversity of native rhizobia associated with A. saligna in Tunisia were studied. A total of 100 bacterial strains were selected and three different ribotypes were identified based on rrs PCR-RFLP analysis. Sequence analyses of rrs and four housekeeping genes (recA, atpD, gyrB and glnII) assigned 30 isolates to four putative new lineages and a single strain to Sinorhizobium meliloti. Thirteen slow-growing isolates representing the most dominant IGS (intergenic spacer) profile clustered distinctly from known rhizobia species within Bradyrhizobium with the closest related species being Bradyrhizobium shewense and Bradyrhizobium niftali, which had 95.17% and 95.1% sequence identity, respectively. Two slow-growing isolates, 1AS28L and 5AS6L, had B. frederekii as their closest species with a sequence identity of 95.2%, an indication that these strains could constitute a new lineage. Strains 1AS14I, 1AS12I and 6AS6 clustered distinctly from known rhizobia species but within the Rhizobium leguminosarum complex (Rlc) with the most closely related species being Rhizobium indicum with 96.3% sequence identity. Similarly, the remaining 11 strains showed 96.9 % and 97.2% similarity values with R. changzhiense and R. indicum, respectively. Based on nodC and nodA phylogenies and cross inoculation tests, these 14 strains of Rlc species clearly diverged from strains of Sinorhizobium and Rlc symbiovars, and formed a new symbiovar for which the name sv. "salignae" is proposed. Bacterial strains isolated in this study that were taxonomically assigned to Bradyrhizobium harbored different symbiotic genes and the data suggested a new symbiovar, for which sv. "cyanophyllae" is proposed. Isolates formed effective nodules on A. saligna.

The isolation of rhizobial strains from the root and stem nodules remains a commonly used method despite its limitations as it enables the identification of mainly dominant symbiotic groups within rhizobial communities. To overcome these limitations, we used genus-specific nifD primers in a culture-independent assessment of Bradyrhizobium communities inhabiting soils in southern Brazil. The majority of nifD sequences were generated from DNA isolated from tropical-lowland pasture soils, although some soil samples originated from the Campos de Cima da Serra volcanic plateau. In the nifD tree, all the bradyrhizobial sequences comprised 38 clades, including 18 new clades. The sequences generated in this study were resolved into 22 clades and 21 singletons. The nifD bradyrhizobial assemblage contained Azorhizobium and α-proteobacterial methylotrophic genera, suggesting that these genera may have acquired their nif loci from Bradyrhizobium donors. The most common in the lowland pasture soils subclade III.3D branch comprises the isolates of mainly an American origin. On the other hand, subclade III.4, which was earlier detected in Brazil among Bradyrhizobium isolates nodulating native lupins, appears more common in the Campos de Cima da Serra soils. The second-largest group, Clade XXXVIII, has not yet been reported in culture-dependent studies, while another common group called Clade I represents a symbiovar predominating in Australia. The identification of the diverse nifD Clade I haplotypes in the tropical-lowland pastures infested by Australian Acacia spp implies that the introduction of these legumes to southern Brazil has resulted in the dissemination of their bradyrhizobial symbionts.

The genus Oodera Westwood, 1874 (Hymenoptera, Pteromalidae, Cleonyminae) is recorded for the first time for the Arabian Peninsula, from the Kingdom of Saudi Arabia and the Sultanate of Oman. The present study is based on specimens reared from xylophagous beetle larvae of the family Buprestidae (Coleoptera) infesting dead Acacia trees from Al-Dakhiliyah and Dhofar governorates in Oman and Al-Baha, Asir and Riyadh regions in Saudi Arabia. Four new species, Oodera arabicasp. nov., O. omanensissp. nov., O. rapuzziisp. nov., and O. similissp. nov. are described, illustrated and compared with closely related Oodera species. An illustrated key and the xylophagous host records of the species are also provided.

The bag shelter moth, Ochrogaster lunifer Herrich-Schaffer, 1855 (Thaumetopoeinae), is abundant and widespread throughout Australia where its larvae have been reported to feed mostly on Acacia and eucalypts. The larvae, known as processionary caterpillars, build silken nests on their host plants either on the ground at the base of the plant (Acacia) or above ground on the trunk or among the canopy (Acacia and eucalypts). The caterpillars are medically important in that they shed tiny setae that can cause dermatitis and other health problems in humans and other mammals, including amnionitis and foetal loss in horses. Despite reports of behavioural, ecological and morphological differences between ground and canopy nesters, caterpillars of all nest types and hosts are currently considered to belong to one species. Here, we use DNA sequence data from the mitochondrial and nuclear genomes of caterpillars taken from different nest types in eastern Australia to determine whether there is evidence for there being more than one species. We find significant genetic divergence between caterpillars from different nest types despite occurrence in sympatry at multiple sites, indicative of a lack of gene flow and the presence of at least two reproductively isolated species. Given the range of hosts and nest locations within hosts throughout Australia, further sampling is needed to determine just how many species there are under the current concept of O. lunifer.

1. Forest–grassland mosaics, with abrupt boundaries between the two vegetation types, occur across the globe. Fire and herbivory are widely considered primary drivers that maintain these mosaics by limiting tree establishment in grasslands, while edaphic factors and frosts are generally considered to be secondary factors that reinforce these effects. However, the relative importance of these drivers likely varies across systems. In particular, although frost is known to occur in many montane tropical mosaics, experimental evidence for its role as a driving factor is limited. 2. We used replicated in situ transplant and warming experiments to examine the role of microclimate (frost and freezing temperatures) and soil in influencing germination and seedling survival of both native forest trees and alien invasive Acacia trees in grasslands of a tropical montane forest–grassland mosaic in the Western Ghats of southern India. 3. Seed germination of both native and alien tree species was higher in grasslands regardless of soil type, indicating that germination was not the limiting stage to tree establishment. However, irrespective of soil type, native seedlings in grasslands incurred high mortality following winter frosts and freezing temperatures relative to native seedlings in adjoining forests where freezing temperatures did not occur. Seedling survival through the tropical winter was thus a primary limitation to native tree establishment in grasslands. In contrast, alien Acacia seedlings in grasslands incurred much lower levels of winter mortality. Experimental night‐time warming in grasslands significantly enhanced over‐winter survival of all tree seedlings, but increases were much greater for alien Acacia than for native tree seedlings. 4. Synthesis. Our results provide evidence for a primary role for frost and freezing temperatures in limiting tree establishment in grasslands of this tropical montane forest–grassland mosaic. Future increases in temperature are likely to release trees from this limitation and favour tree expansion into grasslands, with rates of expansion of non‐native Acacia likely to be much greater than that of native trees. We suggest that studies of frost limitation to plant establishment are needed across a range of tropical ecosystems to re‐evaluate the general importance of frost as a driver of vegetation transitions in the tropics.

This study was undertaken with support from the Natural Heritage Trust Endangered Species Program Grant ESU 00006465.