Dry Rainforest Research Articles

The Conservation of Biodiverse and Threatened Dry Rainforest Plant Communities Is Vital in a Changing Climate

The Conservation of Biodiverse and Threatened Dry Rainforest Plant Communities Is Vital in a Changing Climate

Biogeography of vine thickets and open woodland in subtropical eastern Australia: a case study of three camaenid land snail genera

Dry rainforests and open woodlands occur across much of eastern Australia. However, the biogeographic history of these habitats remains poorly known, especially when compared to nearby moist rainforest areas. Land snails are commonly used as model organisms to understand patterns of origins of regional endemism due to their low vagility. Here we present an analysis of patterns of mitochondrial genetic diversity in three camaenid snail lineages with distributions centred on vine-thicket and open woodland habitats of eastern Queensland, specifically Euryladra from open woodlands, Brigaladra from inland semievergreen vine thickets, and Figuladra from coastal vine thickets. Lineages from habitats west of the Great Dividing Range show relatively low genetic divergence between localities, with particularly low structuring in the open woodland taxon Euryladra. Figuladra from vine-thicket habitats closer to the coast shows relatively deeper genetic divergence, with marked divergences between some upland and lowland areas in south-east Queensland, and across the St Lawrence Gap. This structuring suggests that taxa associated with vine thicket habitats have had a more discernible history of isolation than open woodlands. This said, genetic divergence across many vine thickets patches in lowland coastal regions is also shallow, suggesting many apparently disjunct vine thicket habitats and their associated species also have a recent history of connectivity.

The sicariid spiders in the state of Bahia, Brazil (Arachnida: Araneae).

Sicariidae is a small family of cryptic and recluse spiders, with 178 species grouped into three genera: Hexophtalma, Loxosceles and Sicarius. Only the last two occur in Brazil, where 29 species are recorded, with a greater number of records in the Southeast and South regions. To date, there is no regionalized study of the distribution of these spiders in the Northeast of Brazil. We presented more than four decades of data on the distribution of sicariid spiders in the state of Bahia. Our research aimed to identify and evaluate the distribution of sicariid species in this region, characterizing them in their biomes and phytophysiognomies. Data covers a period from 1983 to 2024, obtained from articles describing species recorded in Bahia and from three scientific collections from Brazilian institutions: Universidade Federal da Bahia (MHNBA); Instituto Butantan (IBSP); Universidade Federal de Minas Gerais (UFMG). Maps were produced using the QGIS 3.34.1 software, based on geographic coordinates obtained from the original literature, when provided. Species without information on geographic coordinates were georeferenced using the SpeciesLink (geoLoc tool) for the municipalities. Biomes were consulted on the georeference Brazilian institute website and the phytophysiognomies were ignored when not specified in the data of collections or original literature. We confirmed 14 species of sicariid spiders in the state of Bahia, eight from the genus Loxosceles (i) and six from Sicarius. The species were recorded in 48 municipalities, located mainly in the Caatinga biome. We recorded a distribution expansion of seven species: Loxosceles amazonica, L. chapadensis, L. karstica, L. similis, Sicarius cariri, S. ornatus and S. tropicus. There is a difference in species composition in the two regions separated by the São Francisco River, an important geographic barrier especially for small invertebrates. More than 75% of the species were registered in the east side and about 20% exclusively in the west side: L. boqueirao, L. cardosoi, L.carinhanha. This suggests the need for future studies to evaluate additional variables that determine community structure, especially considering their low vagility and reclusive behavior. Although Sicarius are found almost exclusively in the Caatinga, there are isolated records from Restinga and dry forest enclaves in the Cerrado domain and Atlantic Forest areas. This reinforces the possibility of them being able to adapt to slightly wetter environments erase colonize and survive in seasonally dry rainforest areas. Unlike Sicarius (i), Loxosceles (i) occupy a wide variety of habitats in natural, urban and domiciliary situations. Many of the records here such as for Loxosceles boqueirao, L. cardosoi, L. carinhanha, L. chapadensis, L. karstica and L. troglobia were obtained at caves or nearby areas, which appear to be attractive habitats for these nocturnal spiders.

Assessment of the Diversity, Distinctiveness and Conservation of Australia’s Central Queensland Coastal Rainforests Using DNA Barcoding

Globally threatened dry rainforests are poorly studied and conserved when compared to mesic rainforests. Investigations of dry rainforest communities within Australia are no exception. We assessed the community diversity, distinctiveness and level of conservation in Central Queensland coastal dry rainforest communities. Our three-marker DNA barcode-based phylogeny, based on rainforest species from the Central Queensland Coast, was combined with the phylogeny from Southeast Queensland. The phylogenetic tree and Central Queensland Coast (CQC) community species lists were used to evaluate phylogenetic diversity (PD) estimates and species composition to pinpoint regions of significant rainforest biodiversity. We evaluated the patterns and relationships between rainforest communities of the biogeographical areas of Central Queensland Coast and Southeast Queensland, and within and between Subregions. Subsequently, we identified areas of the highest distinctiveness and diversity in phylogenetically even rainforest communities, consistent with refugia, and areas significantly more related than random, consistent with expansion into disturbed or harsher areas. We found clear patterns of phylogenetic clustering that suggest that selection pressures for moisture and geology were strong drivers of rainforest distribution and species diversity. These results showed that smaller dry rainforests in Central Queensland Coast (CQC) represented areas of regional plant migration but were inadequately protected. To sustain species diversity and distribution under intense selection pressures of moisture availability and substrate type throughout this dry and geologically complex region, the future conservation of smaller patches is essential.

Canopy plant composition and structure of Cape subtropical dune thicket are predicted by the levels of fire exposure.

The subtropical dune thicket (hereafter "dune thicket") of the Cape Floristic Region experiences a wide range of fire exposure throughout the landscape, unlike other dry rainforest formations that rarely experience fire. We sought to determine how fire exposure influences species composition and the architectural composition of dune thicket. We used multivariate analysis and diversity indices based on cover abundance of species to describe the species composition, architectural guild composition and structure of dune thicket sites subject to different levels of fire exposure, namely low (fire return interval of >100 years), moderate (fire return interval of 50-100 years), and high (fire return interval of 10-50 years). The diversity, cover abundance and architectural guild cover abundance of dune thicket canopy species were strongly influenced by the level of fire exposure such that each level was associated with a well-circumscribed vegetation unit. Dune thickets subject to low fire exposure comprises a floristically distinct, low forest characterized by shrubs with one-to-few upright stems (ca. 4-8 m tall) and a relatively small canopy spread (vertical growers). Of the 25 species in this unit, 40% were restricted to it. Dune thickets subject to moderate fire exposure had the highest abundance of lateral spreaders, which are multi-stemmed (ca. 3-6 m tall) species with a large canopy spread and lower stature than vertical growers. None of the 17 species found in this unit was restricted to it. Dune thickets subject to high fire exposure had the highest abundance of hedge-forming shrubs, these being low shrubs (ca. 0.6-1.4 m tall), with numerous shoots arising from an extensive system of below-ground stems. Of the 20 species in this unit, 40% were restricted to it. Multivariate analysis identified three floristic units corresponding to the three fire exposure regimes. Compositional structure, in terms of species and architectural guilds, was most distinctive for dune thickets subject to high and low fire exposure, while the dune thicket subject to moderate fire exposure showed greatest compositional overlap with the other units. Fire exposure profoundly influenced the composition and structure of dune thicket canopy species in the Cape Floristic Region. In the prolonged absence of fire, the thicket is invaded by vertical-growing species that overtop and outcompete the multi-stemmed, laterally-spreading shrubs that dominate this community. Regular exposure to fire selects for traits that enable thicket species to rapidly compete for canopy cover post-fire via the prolific production of resprouts from basal buds below- and above-ground. The trade-off is that plant height is constrained, as proportionately more resources are allocated to below-ground biomass.

Role of vegetation structure and abiotic factors affecting the temporal dynamics of ant foraging

The study of foraging dynamics is essential to understanding the way organisms arrange themselves to reduce the effects of competition in the most diverse natural systems. The analysis of temporal foraging patterns is an important tool for understanding how ant communities respond to different environmental conditions. Thus, to verify how complexity of the vegetation and abiotic factors can influence ground-dwelling ants communities, we evaluated the foraging temporal patterns in three types of landscapes (Grassland, Arboreal Caatinga, Shrub Caatinga) in an área of dry seasonal rainforest. These environments were characterized by abundance of plant life forms. The ants were collected by pitfall trap, arranged in six rows each with five traps. The pitfalls were inspected every hour from 7:00 am to 6:00 pm, and temperature and humidity data were taken at the same time. The foraging structure of ant communities presented a nested pattern between the phytophysiognomies, but with variation in the observed metric values. For less complex environments, foraging activity was restricted to preferential times, demonstrating a temporal niche partition. Despite more complex environments have a greater richness of species foraging throughout the day, we found greater diversity in environment with intermediate complexity. Temperature influences the richness of foraging ants throughout the day, but we found no effect on diversity. Our results indicate that, although temperature may influence the temporal dynamics of ground-dwelling ant communities, changes in the structural complexity of the environment affect the foraging activity among species, influencing ant-mediated ecological processes.

Madagascar Terrestrial Camera Survey Database 2021: A collation of protected forest camera surveys from 2007-2021.

Madagascar is a threatened global biodiversity hotspot and conservation priority, yet we lack broad-scale surveys to assess biodiversity across space and time. To fill this gap, we collated camera trap surveys, capturing species occurrences within Madagascar into a single standardized database. This data set includes nine distinct protected areas of Madagascar and encompasses 13 subprojects, 38 camera arrays, and 1156 sampling units (independent camera site per survey) within two important biodiversity eco-regions: western dry deciduous forest and eastern humid rainforest. Camera surveys were conducted from June 2007 to January 2021. The final data set includes 17 unique families of mammals (Bovidae, Canidae, Cheirogaleidae, Daubentoniidae, Equidae, Eupleridae, Felidae, Hominidae, Indriidae, Lemuridae, Lepilemuridae, Muridae, Nesomyidae, Pteropodidae, Soricidae, Suidae, Tenrecidae) comprising 45 species and 27 unique families of birds (Accipitridae, Acrocephalidae, Alcedinidae, Bernieridae, Brachypteraciidae, Caprimulgidae, Cisticolidae, Columbidae, Coraciidae, Corvidae, Cuculidae, Dicruridae, Mesitornithidae, Monarchidae, Motacillidae, Muscicapidae, Numididae, Phasianidae, Rallidae, Sarothruridae, Strigidae, Sturnidae, Sulidae, Threskiornithidae, Upupidae, Vangidae, Zosteropidae) comprising 58 species. Images were processed and verified by individual project data set creators and camera operation and species tables were then collated. The final product represents the first broad-scale freely available standardized formal faunal database for Madagascar. Data are available through this publication and at DOI: 10.5281/zenodo.5801806. These data will be useful for examining species-level and community-level trends in occurrence across space or time within Madagascar and globally, evaluating native and invasive species dynamics, and will aid in determining species conservation status and planning for at-risk species. There are no copyright restrictions; please cite this paper when using the data for publication.

Time partitioning among neotropical frugivorous bats: effects of phylogeny, body size, and abundance

Introduction: Resource partitioning by promoting coexistence is essential to determine species richness and composition in natural communities. However, the partitioning of time has been questioned as a mechanism that promotes the coexistence of ecologically similar species. Objective: To determine the importance of the partitioning of time as a mechanism that promotes coexistence, we compared the activity patterns of tropical frugivorous bats. Methods: We captured bats with mist nets from sunset to sunrise in three study sites (tropical dry forest, wet forest, and rainforest) to calculate activity patterns of the species using Kernel density estimation. We used the superposition coefficient (Δ1) to compare activity patterns between (1) bat assemblages of study sites, (2) frugivorous species in the same site, and (3) populations of the same species among different sites. To determine whether the overlap in the activity patterns was related to the ecological similarity of species, we evaluated the association between Δ1 and similarity in abundances and body mass and phylogenetic closeness. Results: We found geographical variations in the overall activity patterns of the assemblages of the three localities. Likewise, we found variations in activity patterns between species at each study site and between populations in different study sites. Overlap in activity patterns tended to decrease as species were phylogenetically more closely related and similar in abundance and body size. Conclusions: Our results provide empirical support for the role of temporal segregation in activity patterns as a mechanism that promotes the coexistence of ecologically similar species in nature.

Global AM fungi are dominating mycorrhizal communities in a tropical premontane dry forest in Laipuna, South Ecuador

Tropical dry forests are an intricate ecosystem with special adaptations to periods of drought. Arbuscular mycorrhizal fungi (AMF) are essential for plant survival in all terrestrial ecosystems but might be of even greater importance in dry forests as plant growth is limited due to nutrient and water deficiency during the dry season. Tropical dry forests in Ecuador are highly endangered, but studies about AMF communities are scarce. We investigated the AMF community of a premontane semi-deciduous dry forest in South Ecuador during the dry season. We estimated AMF diversity, distribution, and composition of the study site based on operational taxonomic units (OTUs) and compared the results to those from the tropical montane rainforest and páramo in South Ecuador. OTU delimitation was based on part of the small ribosomal subunit obtained by cloning and Sanger sequencing. Nearly all OTUs were Glomeraceae. The four frequent OTUs were Glomus, and comparison with the MaarjAM database revealed these to be globally distributed with a wide range of ecological adaptations. Several OTUs are shared with virtual taxa from dry forests in Africa. Ordination analysis of AMF communities from the tropical dry and montane rainforests in South Ecuador revealed a unique AMF community in the dry forest with only few overlapping OTUs. Most OTUs that were found in both dry and rainforests and on the two continents were globally distributed Glomus.

The potential of alfisols developed on different parent materials in two agro-ecological zones for oil palm production in Nigeria

The excessive use and lack of information on the properties and potentials of agricultural land have led to misuse, mismanagement, soil erosion and loss of soil quality in the tropics. Land suitability evaluation is a tool for assessing the potential of land for the cultivation of specific crops. The study was conducted during 2018 and 2019 on soils of two agro-ecological zones of dry upland rainforest (Ado-Ekiti) and southern guinea savanna (Kabba) of Nigeria. They were mapped, characterized and classified for their potential to support the cultivation of oil palm. Seven mapping units were delineated at Ado-Ekiti (labeled AA to AG) and nine units at Kabba (labeled KA to KI). Based on the principle of matching land qualities and climatic requirements of crop to the characteristics of the land, the suitability classification of the soils mapping units was developed. Mapping units KA, KD, KG, KH, KI, AA, AB, AD, AE and AF have index of actual productivity (IPC) lower than 50% therefore they were rated as currently marginally suitable (S3) for oil palm production. KB, KC, KE, KF, and AC were currently not suitable (N1) while AG was permanently not suitable. The major limitations to oil palm production at both sites were rainfall, poor soil drainage condition in some portion and soil fertility. Fertility is a limitation that can be improved with appropriate post-harvest crop residue management and mulching, use of organic manure and biosolids, legumes in crop rotations; judicious use of inorganic fertilizer and integration of fertilizer with manures these will raise the productivity of mapping units KB, KF, KG, KH and AA, AB, AC, AD to AF to class S2; moderately suitable for oil palm production.

A concise comparison of two rainfall onset definitions using convective properties derived from TRMM precipitation radar data

Most rainfall onset definitions in West Africa were estimated using station-based data. These data and hence the rainfall onset definitions may, however, not be a good representative for the entire climatic zone of the station. Based on existing definitions, a new rainfall onset definition is developed from the Tropical Rainfall Measurement Mission 3B42 gridded rainfall observations. 16 years of data were analyzed, which were taken between mid-April to mid-July over rainforest zones (west coast rainforest, dry rainforest and Nigeria–Cameroon rainforest) and between mid-May to mid-August over savannah zones (Nigeria savannah, and “Central African and South Sudan savannah”). While both definitions yield rather similar results in west coast rainforest, Nigeria–Cameroon rainforest and Nigeria savannah zones; results differ, however, substantially over dry rainforest and the Central African and South Sudan savannah. The new onset definition is further justified using an event-based analysis of mesoscale convective systems, flash counts and other convective parameters. Results have proved the new onset definition to be reliable and relevant for applications in agricultural productivity.

Vertical structure and frequencies of deep convection during active periods of the West and Central African monsoon season

Deep convective systems during active periods of the West African monsoon season have not been properly investigated over better temporal and spatial resolution in West Africa. Deep convective systems are investigated over seven climatic zones of the West African sub-region, which are as follows: west-coast rainforest, dry rainforest, Nigeria-Cameroon rainforest, Nigeria savannah, Central African and South Sudan (CASS) savannah, Sudano-Sahel, and Sahel, using data from Tropical Rainfall Measurement Mission (TRMM) Precipitation Feature (PF) database. The vertical structure of the convective systems indicated by the presence of at least one 40 dBZ and reaching (attaining) at least 1 km in the atmosphere showed strong core (highest frequency (%)) of reflectivity values around 2 km which is below the freezing level (4–5 km) for all the zones. Echoes are detected above the 15-km altitude much more frequently in the rainforest and Savannah zones than the Sudano and Sahel zones during active periods in March–May (MAM), whereas during active periods in June–September (JJAS), the savannahs, Sudano, and Sahel zone convections tend to reach higher altitude more frequently than the rainforest zones. The frequencies of deep convection defined by the presence of at least one 40 dBZ, reaching (attaining) at least 1 km in the atmosphere, with sizes greater than 2000 square, and having at least one convective pixels indicate that these systems are within the range of 2.3–2.8% in frequency averaged over the 16-year period of study in both March–May (MAM) and June–September (JJAS) active periods in the rainforest and savannah zones. These were found to be less than 2% in the Sudano and Sahel zones, except for the active JJAS period in Sudano zone.

Effect of Manure and Urea Fertilization on Yield, Carbon Speciation and Greenhouse Gas Emissions from Vegetable Production Systems of Nigeria and Republic of Benin: A Phytotron Study

Fertility management techniques being promoted in sub-Saharan Africa (SSA) seek to grow indigenous vegetables economically and sustainably. This study was conducted in a phytotron chamber and compared yield, soil carbon (C) speciation and greenhouse gas (nitrous oxide (N2O) and carbon dioxide (CO2)) emissions from SSA soils of two ecoregions; the dry savanna (lna, Republic of Benin) and rainforest (Ife, Nigeria) cultivated with local amaranth (Amaranthus cruentus) under manure (5 t/ha) and/or urea (80 kg N/ha) fertilization. Vegetable yield ranged from 4331 kg/ha to 7900 kg/ha in the rainforest, RF, soils and 3165 kg/ha to 4821 kg/ha in the dry savanna, DS, soils. Yield in the urea treatment was slightly higher compared to the manure, and manure+urea treatment, but the difference was not statistically significant. Cumulative CO2 emissions over 21 days ranged from 497.06 to 579.47 g CO2-C/kg soil/day in the RF, and 322.96 to 624.97 g CO2-C/kg soil/day in the DS, while cumulative N2O emissions ranged from 60.53 to 220.86 mg N2O-N/kg soil/day in the RF, and 24.78 to 99.08 mg N2O-N/kg soil/day in the DS. In the RF samples, when compared to the use of urea alone, the combined use of manure and urea reduced N2O emissions but led to an increase in the DS samples. ATR-FTIR analysis showed that the combined use of manure and manure+urea increased the rate of microbial decomposition in the soils of the DS, but no such effect was observed in soils of the RF. We conclude that combining manure and urea fertilization has different effects on soils of the two ecoregions, and that RF farmers can reduce agricultural N2O emissions without compromising soil productivity and yield potential.

Agro-Climato-Edaphic Zonation of Nigeria for a Cassava Cultivar using GIS-Based Analysis of Data from 1961 to 2017

To investigate the optimal cultivation conditions for cassava cultivar (TMS98/0505) in Nigeria, we employed agro-ecological zoning to delineate the cultivated lands. Using GIS-based multi-criteria analysis, we researched the influence of some meteorological and soil parameters on the clone cultivation. From the multiple-parameter climato-edaphic zoning map, an average yield of 26 t ha−1 was estimated. The dry Rainforest and southern Guinea Savanna account for 80% of the favorable zones. However, with irrigation, the cultivar would yield optimally in the northern marginal zones. Further, the significant climatic parameters are sunshine hour (t = 3.292, α = 0.0064) and rainfall (t = 2.100, α = 0.0575). Thus, the potentials of a location for cassava cultivation in Nigeria largely depend on the soil conditions, sunshine hour, and rainfall. Generally, the cassava yield correlates strongly (+0.88) with the suitability map. Considering future climate variability based on the annual rainfall data, we projected an average annual rainfall range of 565–3,193 mm between 2070 and 2099. Likewise, the projected range of daily temperature for 2046–2100 is 24.57–31.94 °C. Consequently, with currently allotted farmlands, Nigeria can double her current cassava production through soil fertility enhancement and irrigation.

A new species of Phyllurus leaf-tailed gecko (Lacertilia: Carphodactylidae)from The Pinnacles, north-east Australia.

Recent surveys of rocky rainforest in the Townsville region have found additional populations of Phyllurus geckos. One of these populations was discovered at The Pinnacles, an isolated area of habitat in between the distributions of P. gulbaru and P. amnicola. Genetic and morphological data shows that this population is most similar to P. gulbaru Hoskin, Couper Schneider, 2003 but divergent in a number of traits. Here we describe this population as a new species, P. pinnaclensis sp. nov., based on genetic divergence and differences in a number of morphometric and scalation traits from other populations of Phyllurus. Phyllurus pinnaclensis sp. nov. appears to be restricted to a few small areas of deeply layered rock with associated dry rainforest. This habitat is fire-sensitive and increased frequency and intensity of fires (due to late season burns and high fuel loads of invasive grasses) threatens to reduce and fragment these dry rainforest patches. Other threats include potential future invasion of the habitat by introduced Asian House Geckos (Hemidactylus frenatus Duméril Bibron, 1836) and illegal collecting. Given the very small and fragmented distribution and potential reduction in habitat area due to fire, P. pinnaclensis sp. nov. warrants a Critically Endangered listing. Resolving the distributional change of dry rainforest in the Townsville region in recent decades, particularly in regards to fire, is key to resolving the status of this and other locally threatened taxa that depend on this habitat.

Range extension and genetic structure of the narrowly-restricted slider skink, Lerista rochfordensis Amey and Couper, 2009 (Reptilia: Scincidae)

Recent field surveys have collected more information on the poorly known species, Lerista rochfordensis. Previously known only from one dry rainforest patch of around 2 000 hectares in northern Queensland, the species was discovered in a neighbouring patch, 8 km distant, itself about 1 600 hectares in extent. The two populations are separated by cleared grazing land and the Kirk River, an ephemeral tributary of the Burdekin River. Statistically significant but comparatively small genetic and morphological divergence was observed between the two populations, suggesting they should still be considered conspecific under the Evolutionary Species Concept but are undergoing allopatric speciation.

Three new species of Trigonospila Pokorny (Diptera: Tachinidae), from Area de Conservación Guanacaste, northwestern Costa Rica, with a key for their identification.

We describe three new species of Trigonospila Pokorny (Tachinidae: Blondeliini) from Area de Conservación Guanacaste (ACG), northwestern Costa Rica. All were reared from ­various species of ACG caterpillars during an ongoing inventory of caterpillars, their food plants and their parasitoids in dry forest, rain forest and cloud forest. By coupling morphology, photographic documentation, life history and molecular data, we provide a clear and concise description of each species. All species published as new, are known to be previously undescribed as a result of careful study of the genus by DMW. This study builds on the current knowledge of the genus by adding three new species to the current 7 described in the New World. Trigonospila edwinbermudezi sp. n., Trigonospila uniformis sp. n., and Trigonospila josemariamoragai sp. n. are all authored and described as new by Fleming and Wood, with a key to their identification. The authors also offer a new record and description of the previously unknown male of Trigonospila panamensis (Townsend), reared from ACG caterpillars.

Fauna of the grassland-forest landscape mosaics of the Bunya Mountains, eastern Australia

Fauna assemblages were assessed within four primary vegetation types and three edge types between grassland and wooded habitats within the Bunya Mountains of eastern Australia. Wet rainforests differed in their species assemblages to dry rainforest, savanna woodland and grassy bald. Dry rainforests and savanna woodlands had similar species composition despite their dissimilar floristic and structural attributes. The small grassy balds supported lower vertebrate species richness and abundance and were significantly different in species composition to all other vegetation types. The small and structurally simple grassy balds contained a subset of species also found in surrounding forest and woodland vegetation, with only a few grassland specific species. Fauna assemblages in grassy bald-rainforest edges were significantly different to grassy balds and rainforest interiors, while grassy bald-savanna woodland edges were similar to savanna woodland interiors. The reptile Lampropholis colossus, the only endemic...

The Diversity and Antimicrobial Activity of Preussia sp. Endophytes Isolated from Australian Dry Rainforests

Limited knowledge currently exists regarding species diversity and antimicrobial activity of endophytic isolates of Preussia within Australia. This report describes endophytic Preussia species that were identified through molecular analysis of the internal transcribed spacer region. Screening for antimicrobial secondary metabolites was determined by testing crude ethyl acetate (EtOAc) extracts derived from fungal mycelia against a panel of ATCC type strains which included Bacillus cereus, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Serratia marcescens, methicillin-resistant Staphylococcus aureus (MRSA) and the opportunist yeast pathogen Candida albicans. Subsequently, high-performance liquid chromatography generated fractions of bioactive EtOAc extracts which were subject to confirmatory testing using the Clinical and Laboratory Standards Institute reference microdilution antimicrobial activity assay. A total of 18 Preussia were isolated from nine host plants with 6/18 having a<97% sequence similarity to other known species in Genbank, suggesting that they are new species. In preliminary screening, 13/18 Preussia isolates revealed antimicrobial activity against at least one of the microbes tested, whilst 6/18 isolates, including 4/6 putative new species showed specific antimicrobial activity against MRSA and C. albicans. These results highlight the antimicrobial potential of Australian Preussia spp. and also the importance of Australian dry rainforests as an untapped repository of potentially significant bioactive compounds.

Drought survival of Australian rainforest seedlings is influenced by species evolutionary history and soil type

Water availability influences regional tree distributions in rainforests, often by affecting survival of seedlings. The occurrence of ‘dry rainforest’ species in subhumid climates has been attributed to the evolution of drought-resistant species from their mesic rainforest congeners. Many genera are found in both dry and mesic rainforest of Australia but the extent to which this is due to differential drought resistance has not been confirmed experimentally. We compared drought survival within three congeneric pairs of dry and mesic rainforest taxa in a glasshouse dry-down experiment. Soil type could also play a role, with dry rainforests mostly occurring on fine-textured soils such as loams, which have a high available water-holding capacity, compensating for lower rainfall. Hence, we grew plants in loam or sand soil. In all pairs, the dry rainforest taxon was better able to survive drought, providing support for the climate-induced evolution of a dry rainforest flora and further confirming that drought resistance of seedlings can shape tree species distributions at regional scales. Two of three pairs had higher seedling survival on basalt-derived loam soil, suggesting that such soils may aid seedling persistence during drought. Over evolutionary time, this may have resulted in the high fidelity of dry rainforest for these soils.