Periods Of Low Rainfall Research Articles

Meerkat helpers buffer the detrimental effects of adverse environmental conditions on fecundity, growth and survival.

Recent comparative studies show that cooperative breeding is positively correlated with harsh and unpredictable environments and it is suggested that this association occurs because helpers buffer the negative effects of adverse ecological conditions on fitness. In the Kalahari, rainfall varies widely between- and within years, affecting primary production and the availability of the principal prey of cooperatively breeding Kalahari meerkats, Suricata suricatta. Our study aimed to establish whether the presence and number of helpers buffer the negative effects of variation in rainfall on the fecundity and body mass of breeding females, and the survival and growth of pups. We investigate the relationship between group size and variation in rainfall on dominant female fecundity, body mass, and offspring survival and growth using an additive modelling approach on 21years of individual-based records of the life histories of individual meerkats. We show that breeding female fecundity is reduced during periods of low rainfall but that the effects of low rainfall are mitigated by increases in group size and body mass because heavier females and those in larger groups have increased fecundity and reduced interbirth intervals. Pup growth and survival are also reduced during periods of low rainfall, but only in smaller groups. Our results support the suggestion that cooperative breeding mitigates the detrimental effects of adverse environmental conditions and may enhance the capacity of species to occupy environments where food availability is low and unpredictable.

Baseflow estimation in typical catchments in the Yellow River Basin, China

Abstract Baseflow is crucial to maintaining river flow during low-rainfall periods. The baseflow estimation is important to water supply and ecological environmental protection in the Yellow River Basin (YRB), China. This paper comprehensively assessed the applicability of four single-parameter digital filtering, recursive digital filtering, and HYSEP (streamflow hydrograph separation) methods across four typical catchments in the Yellow River Basin: the Zuli River Basin, the Kuye River Basin, the Tuwei River Basin, and the Jingle sub-basin. We also investigated annual and monthly variations in baseflow. We found the standard deviation and coefficient of variation of baseflow index through recursive digital filter were relatively small. And the baseflow process line was smoother and more reasonable in typical year and typical storm-flood events, which conformed to the damping and hysteresis effect of the underlying surface. Thus the recursive digital filter method had the best performance, which was recommended for baseflow separation in the YRB. The estimated baseflow index of typical basins were between 0.354 and 0.502. In addition, inter-annual baseflow showed a decreasing trend and intra-annual baseflow was characterized by uneven distribution, which was subject to the characteristics of each basin.

Stress gradients and biodiversity: monoculture vulnerability drives stronger biodiversity effects during drought years.

Climate change will increase the likelihood and severity of droughts into the future. Although diversity may buffer plant communities against the negative effects of drought, the mechanisms underlying this pattern remain unclear. Higher-diversity plant communities may have a higher likelihood of including more drought-resistant species that can compensate for drought-sensitive species ("insurance effects"). Alternatively, higher-diversity communities may alter environmental conditions and improve performance of even drought-sensitive species. Here we planted nonleguminous forbs and grasses into monocultures and four- and eight-species mixtures, and measured species and plot productivity every year from 2000 to 2010. We found that six of our eight species were suppressed when growing in monoculture during dry years. These same species were unaffected by drought when growing in higher-diversity mixtures. Because of this poor performance in monoculture (not insurance effects), the biodiversity productivity relationship was strongest during the driest years. If biodiversity ameliorates hot/dry conditions and therefore improves performance of drought-sensitive species during periods of low rainfall, this may mean biodiversity can be used as a tool to protect individual species from drought conditions.

The Baltic Sea and the adjacent North Sea silicate concentrations

From 1970 to 2000, the yearly Baltic Sea River Runoff (BSRR) together with the silicate concentrations in the Baltic (BS) and North Sea (NS) were observed. We found that the concentrations of silicates were consistently higher in the BS. Furthermore, long-term changes in both ecosystems indicated an overall decrease of Si with increased BSRR. Silicate concentrations were also modelled in two setups of Generalised Linear Mixed Models. Selected exceptional (high and low) BSRR events were used as a predictor in the models. The results suggest that the whole BS acts as a silicate source for the studied, adjacent NS areas. Modelling indicated that the periods with low BSRR show generally higher silicate levels in BS water. In the NS, however, the silicate concentrations decrease with low BSRR periods and increase at high. We point out that the increase of rainfall, and consequently the BSRR, has predominantly taken place in the northern parts of the BS basin, where the ground silicate concentrations are lower than in the southern BS. Therefore, we present, as a conceptual model and a subject for further research, that the BS potentially has acted as a concentrating basin for silicates during periods of normal and low rainfall, while episodic high runoff periods flush the BS surface water including the silicates through the Danish Sounds and into the adjacent parts of the NS. In a post hoc test, we found that also the reproductive success of the NS herring showed a correlation to silicate concentrations thus partially demonstrating the existence of a Si-related, bottom-up regulation.

Study of regional heterogeneity of cloud properties during different rainfall scenarios over monsoon-dominated region

AbstractVariability in precipitation pattern is increasing even at regional scale due to advancement in global warming, which could be of higher importance in study for monsoon-dominated region such as India. Precipitation varies with region, thus the present study focuses on two types of heterogeneous regions: a region closer to the coast and an inland region. Long-term analysis over inland region shows that the high cloud fraction and low penetration of outgoing radiation at the top of the atmosphere may be due to the presence of thicker clouds during southwest monsoon. Further study of cloud parameters shows domination of stratiform clouds over nearby coastal region with high range specific humidity (6.67 × 10−6–1.81 × 10−2 kg/kg) and higher cloud effective radius (13.35–15.75 μm), probably due to fewer hygroscopic nuclei. Heterogeneity in rainfall may also depend on types of monsoon (viz., normal, excess and deficit) by altering cloud formation processes. During periods of low rainfall over the coast, clouds are observed at low altitude with high cloud top temperature (−0.52 ± 3.08 °C) but have low specific humidity and lower cloud effective radius, which depict mixed characteristics of stratiform and convective clouds. Thus, it has been observed that cloud characteristics depend largely on the region than on the rainfall scenario. Such studies can be useful to understand uneven rainfall patterns.

Survival analysis of water distribution network under intermittent water supply conditions

Abstract Intermittent water supply (IWS) is established temporarily or continuously in many water distribution networks (WDNs) worldwide due to prolonged drought, low rainfall periods, water scarcity and high level of leakage. IWS causes several adverse consequences on the network operation, resulting in ineffective supply and demand management. This paper presents a survival analysis of the network elements, including water mains, service connections, and valves using the Kaplan-Meier approach to determine the survival probability and the probability of failure rates of events of interest. The objective is to explore the changes in failure rates of network elements after implementing an IWS scheme. The non-parametric survival method is applied to the large zone (Zone-5) of the WDN in Tehran (Iran) based on the frequency of failures before, during, and after the implementation of an IWS regime. The results show that the probability of failure rates significantly increase after implementing the IWS scheme, and can remain for several years after, even when the network returns to continuous water supply (CWS). The results of this study can assist utility managers to understand the detrimental effects of IWS systems on increasing failure rates.

Goat movement patterns inform management of feral goat populations in semiarid rangelands

Abstract ContextFeral goats (Capra hircus) are a significant pest species throughout southern Australia. They threaten rare plants, contribute to soil erosion, compete with domestic stock, and are implicated in the decline of several native herbivores. Feral goats are a declared pest and control is often implemented. AimsWe fitted feral goats with GPS collars in semiarid South Australia to determine whether they could provide valuable information for regional management. MethodsNineteen feral goats (6 males and 13 females) were fitted with GPS collars between 2009 and 2018. Kernel-density estimates (KDE) were used to estimate annual and seasonal home range and core areas and habitat selection. The effect of monthly rainfall, daily maximum temperatures, and watering points on movement patterns was investigated. Key resultsStock watering points and rock holes were used by some radio-tracked goats intermittently when available; however, goats survived and reproduced without the use of these water sources. The use of the radio-collared goats as Judas goats helped facilitate the removal of 9725 goats from a 50000-ha area over 8 years. There was no significant difference between male and female annual or seasonal home ranges, with 95% MCP annual ranges of 11533ha and 15996ha for males and females respectively. Summer ranges were smaller than winter ranges. There was no difference in daily distance moved between sexes (average 3.4km), but goats moved further in low-rainfall periods. Goats spent most of their time in mallee woodlands, the dominant habitat type available, but preferred shrubland of >1-m height and used less mallee woodland and shrubland of <1-m height than was expected from availability. During hotter periods, these habitat preferences became more distinct. ConclusionsTo reduce goat abundance on a property, active control and waterpoint closure need to extend more than 15km from property boundaries, and shrubland habitat of >1-m height should be targeted for control after rainfall events when goats move less. Radio-collared goats provided important habitat-preference information to inform priority areas for goat control remote from water sources. ImplicationsClosing artificial watering point and regular trapping and mustering at remaining waters is insufficient to remove residual goat herds without additional targeted control in preferred habitat.

Nutritional muscular dystrophy in lambs reared on pasture in semiarid region of Brazil

This article presents important data on the diagnosis of nutritional muscular dystrophy (NMD) in sheep reared in the semiarid region of Northeast Brazil, with a focus on medical clinic data, nutritional management, anatomopathological aspects and quantification of serum selenium by highly sensitive analytical methodology. The semiarid region of Brazil is of great importance in the creation of small ruminants and many diseases that affect herds are related to failures in nutritional management, sanitary measures, periods of greater drought or low rainfall, little availability of native forage at certain times of the year and lack of supplementation with energy nutrients, proteins and minerals. The lack of publications on outbreaks of selenium deficiency demonstrates the importance of diagnosing in this area. The mean concentration of Se in the serum from the lambs was very low (2.52±1.02µg/L). The findings in the skeletal muscles are compatible with the characteristics observed in NMD, characterized by necrosis and calcification of myofibrils. In addition, necrotizing vasculitis in hepatic arterioles and hepatocellular coagulation necrosis in hepatocytes were observed, probably triggered by lipid peroxidation of cell membranes. The lambs from this outbreak, reared on pasture in the semiarid region, presented low serum Se concentration, with clinical and anatomopathological manifestation of NMD. Thus, supplementation with Se in the diet should be recommended regularly to avoid the appearance of new cases. Serum Se levels are useful indicators for the diagnosis of nutritional muscular dystrophy in lambs, associated with clinical and anatomopathological data.

Uncarina roeosliana Rauh ontomorphogenesis in early stages of development

The aim. To find out the morphology of the seeds and the features of its germination and to study the development of Uncarina roeoesliana Rauh (Pedaliaceae) plants in the early stages of ontogeny in connection with the problem of a seed germination and their cultivation under introduction.Materials and methods. The latent and pregenerative periods of the ontomorphogenesis of Uncarina roeoesliana plants under growing conditions in the protected soils of the Botanical garden named after acad. O.V. Fomin were investigated. Biomorphological, introducting, histological methods were used in this work.Results. A method of accelerating the germination of freshly harvested seeds has been developed. Uncarina roeoesliana seeds are large (about 7x5 mm), mostly wide-triangular, brown in colour with little-noticed wing around the perimeter of the seed. The dorsal side forms folds, the hem is on the micropillary part of the seed. The periclinal walls are convex and often with papillae. The embryo is large, occupies most of the seed, the endosperm has a lot of lipids, which is typical for the representative of the same family Sesamum indicum L. The presence of papillae probably contributes to the moisture accumulation to increase the enzymatic activity when the seeds are swell. All of these features of seed germination are consistent with the environmental conditions of Uncarina's natural habitats: high temperatures, low rainfall and significant dry periods. Probably the plants of this species belong to macrobiotics, that is, they can retain seed germination for a long time. The germination is aboveground. During the 24 weeks of development, the plants reach the virginal stage of development: they form radish roots, 5-6 pairs of leaves, of which only two pairs remain in the young plants at this stage, and a thickened basal part of the stem .Conclusions. Comparing Uncarina roeoesliana with other caudiciform plants, we can conclude that this plant has a high potential for survival in arid conditions due to the ability of seeds to germinate only in conditions of considerable moisture and the ability of the plant to accumulate moisture in the basal part of the stem and in fleshy roots. In this case, the plant is adapted to exist both in the mode of a dormancy and in the mode of an active growth, but in the latter case only in the presence of sufficient moisture in the soil

Precipitation influences on the net primary productivity of a tropical seasonal rainforest in Southwest China: A 9-year case study

The net primary productivity (NPP) of tropical forests is a key part of the global carbon cycle. Numerous studies have estimated tropical forest NPP, yet most of them focus on how annual NPP dynamics vary over several years. Little is known about how NPP responds to long-term climatic variation at the monthly or seasonal scales. We estimated NPP at three-month intervals from 2009 to 2017 for a tropical seasonal rainforest in Xishuangbanna, Southwest China using data from >2000 dendrometer bands and litter fall traps within a 20-ha permanent forest dynamics plot. We asked which climatic factor has the greatest effect on forest NPP at the sub annual scale, and how the relationships vary with seasonality. Calculations showed that NPP ranged from 12 to 20 t ha−1 yr−1, and that forest productivity showed a slight, but insignificant increase from 2009 to 2017. NPP was significantly higher in the wet season than that in the dry season and was significantly related to precipitation only when all data were concerned. During the dry season, precipitation had a significant positive influence on NPP, but no effect during the wet season. We further identified that there was a threshold effect of precipitation on NPP. Specifically, productivity increased more rapidly when monthly precipitation below 229 mm. In summary, we conclude that periods of low rainfall strongly regulate the productivity in this tropical seasonal rainforest which could guide the management design of water use efficiency in tree based land-use system, like agroforestry ecosystems.

Using time domain reflectometry to estimate water content of three soil orders under savanna in Brazil

Water is a limiting factor in agricultural lands on tropical Savannas. Due to low rainfall and long periods of drought, irrigation becomes a critical factor for increasing productivity. In this scenario, improving irrigation management techniques is crucial for increasing water use efficiency. Soil water content sensors are important tools not only for soil-based irrigation scheduling, but also to calibrate weather-based irrigation scheduling. Time domain reflectometry (TDR) type sensors are an important tool for water content monitoring due to its potential accuracy, automation and real-time measurement capability. The objective of this study was to evaluate the TDR technique for the estimation of water content in five soils of the Brazilian savanna (two Oxisols, two Entisols and one Histosol) using polynomial, square root and logarithmic calibration equations. The influence of soil bulk density, organic matter and clay content, and presence of magnetic materials were also examined. Magnetic permeability was estimated from magnetic hysteresis curves for each soil. The equations were calibrated and validated on an independent data set. Validation was evaluated using the Coefficient of Determination (R2), Root Mean Squared Error (RMSE), Nash-Sutcliffe Efficiency and the RMSE to the standard deviation of observed data ratio. There was no benefit of including bulk density, clay content or organic matter on the calibration equations. The relative magnetic permeability was very close to one in all soils and thus did not influence the calibration. For the soils evaluated in this study a single logarithmic calibration equation calibrated for all samples was the best predictor of volumetric water content.

Spatiotemporal variation in microplastic contamination along a subtropical reservoir shoreline.

Microplastics have become a major environmental concern globally due to their potential impact on ecosystem function. They are known to be ubiquitously present, persistent and bio-accumulative, yet there is a lack of abundance quantifications in freshwater shorelines. Furthermore, there is little understanding of combined effects of seasonality and human population density on the extent of microplastic pollution. In this study, we assessed microplastics in sediment along a subtropical reservoir shoreline across three seasons and seven sites to understand microplastic pollution dynamics along a human population gradient. Multivariable analysis was used to assess relationships among substrate embeddedness, sediment organic matter, human population density and microplastic particle densities and characteristics. Microplastic densities were relatively high during the hot-dry season (mean range 120-6417 particles kg-1 dwt) whilst the hot-wet season had the lowest densities (mean range 5-94 particles kg-1 dwt). Microplastic abundances were positively correlated with population density, demonstrating the direct effects of human activity on microplastic contamination. These results highlight the need to further explore microplastic distribution patterns in freshwater ecosystems in theSouthern Hemisphere. Furthermore, our findings suggest particular risk for fauna during low rainfall periods through microplastic concentration effects.

Survival Benefits of Group Living in a Fluctuating Environment.

Group living is predicted to arise only when the fitness benefits outweigh the costs of sociality. Group-living species-including cooperatively breeding and family-living birds and mammals-occur most frequently in environments where climatic conditions fluctuate unpredictably from year to year. The fitness consequences of group living are thus expected to vary with changing environmental conditions, though few studies have examined this possibility. We examined whether living in large social groups improves adult survivorship in cooperatively breeding superb starlings (Lamprotornis superbus). We also tested the hypothesis that larger groups buffer against harsh conditions by increasing survivorship most under periods of low rainfall. We found that group size was positively correlated with adult survival but in a sex-specific manner: female survival increased with group size across all environmental conditions, whereas male survival increased with group size only in wet years. Together with previous work in this system, our results suggest that larger groups confer survival benefits by reducing predation, rather than by improving access to food or buffering against physiological stress. Although group living does not appear to buffer against harsh conditions in adult starlings living in a fluctuating environment, living in larger groups does confer a survival advantage.

Temperature Impacts the Response of Coffea canephora to Decreasing Soil Water Availability

Climate change is expected to result in more frequent periods of both low rainfall and above normal temperatures for many coffee growing regions. To understand how coffee reacts to such change, we studied the physiological and gene expression responses of the clonal variety C. canephora FRT07 exposed to water deficits under two different temperature regimes. Variations in the time-dependent impact of water deficits on leaf stomatal conductance and carbon assimilation were significantly different under the 27 °C and 27 °C/42 °C conditions examined. The physiological responses 24 h after re-watering were also different for both conditions. Expression analysis of genes known to respond to water deficits indicated that drought-related signaling occurred at both temperatures. Deeper insights into the response of coffee to water deficits was obtained by RNASeq based whole transcriptome profiling of leaves from early, late, and recovery stages of the 27 °C experiment. This yielded expression data for 13,642 genes and related differential expression analysis uncovered 362 and 474 genes with increased and decreased expression, respectively, under mild water deficits, and 1627 genes and 2197 genes, respectively, under more severe water deficits. The data presented, from a single clonal coffee variety, serves as an important reference point for future comparative physiological/transcriptomic studies with clonal coffee varieties with different sensitivities to water deficits and high temperatures. Such comparative analyses will help predict how different coffee varieties respond to changing climatic conditions, and may facilitate the identification of alleles associated with high and low tolerance to water deficits, enabling faster breeding of more climate-smart coffee trees.

Assessing potential locations for flood-based farming using satellite imagery: a case study of Afar region, Ethiopia

AbstractThe dry lowlands of Ethiopia are seasonally affected by long periods of low rainfall and, coinciding with rainfall in the Amhara highlands, flood waters which flow onto the lowlands resulting in damage to landscapes and settlements. In an attempt to convert water from storm generated floods into productive use, this study proposes a methodology using remote sensing data and geographical information system tools to identify potential sites where flood spreading weirs may be installed and farming systems developed which produce food and fodder for poor rural communities. First, land use land cover maps for the study area were developed using Landsat-8 and MODIS temporal data. Sentinel-1 data at 10 and 20 m resolution on a 12-day basis were then used to determine flood prone areas. Slope and drainage maps were derived from Shuttle RADAR Topography Mission Digital Elevation Model at 90 m spatial resolution. Accuracy assessment using ground survey data showed that overall accuracies (correctness) of the land use/land cover classes were 86% with kappa 0.82. Coinciding with rainfall in the uplands, March and April are the months with flood events in the short growing season (belg) and June, July and August have flood events during the major (meher) season. In the Afar region, there is potentially >0.55 m ha land available for development using seasonal flood waters from belg or meher seasons. During the 4 years of monitoring (2015–2018), a minimum of 142,000 and 172,000 ha of land were flooded in the belg and meher seasons, respectively. The dominant flooded areas were found in slope classes of <2% with spatial coverage varying across the districts. We concluded that Afar has a huge potential for flood-based technology implementation and recommend further investigation into the investments needed to support new socio-economic opportunities and implications for the local agro-pastoral communities.

Genotypic Variation in Potato Growth and Yield Response to Water Stress During two Production Seasons in Northwest Ethiopia

Water stress during low-rainfall periods (Mesino and Belg) constrains the potato from meeting full yield potential in northwest Ethiopia. Farmers tend to grow local varieties in these seasons but these varieties have not been tested for their water stress tolerance. Therefore, the present study was conducted to evaluate major Ethiopian local varieties for their drought tolerance under controlled conditions in two growing seasons, and to compare these with a few selected varieties from outside sources. Nine local varieties and six new varieties were tested in the screen house at Adet Agricultural research center in both Mesino and Belg seasons for their response to moderate water stress conditions during 2014. All varieties were grown under two water regimes (well-irrigated and stressed) maintained by monitoring soil moisture. The results showed that, averaging across varieties, the marketable tuber yield losses due to water stress in Mesino (residual production) and Belg seasons were 28% and 67%, respectively. Substantial differences between varieties in growth and yield response to both growing season and water stress were also observed. In the Mesino season, although no variety out-yielded the main local variety, ‘Siquare’, under drought conditions, “Belete”, “CIP-395109.34”, “Abadamu” and “Granola” had showed the lowest water stress susceptibility index (SSI) and higher marketable tuber yield in stress condition. In the Belg season, ‘Granola’ followed by ‘Abadamu’ and “Gera” had the highest marketable tuber yields under both irrigated and stress conditions and the lowest water stress susceptibility index. Traits associated with high marketable yield potential and stability under stress condition include: high harvest index, increased root length, relatively few deformed and small sized tubers under stress. The results indicated potential for improving dry season potato production in Ethiopia by utilizing both selected local and new varieties.

Hydroclimate influences on modern pollen rain of upland southeastern Amazonia

For accurate interpretations of palaeopalynological data, it is important to understand the influence of the current vegetation composition and characteristics on the formation of the palynological assemblage recorded in artificial or natural pollen traps. Therefore, in this study, modern pollen rain was characterized using artificial pollen traps under different ecological conditions and climatic seasons in Trilha da Mata Lake, Carajás North Ridge, southeastern Amazonia. The collection of pollen rain data comprises the total period from September 2015 to August 2016. There were two periods of low rainfall (September to December 2015 and May to August 2016) and one period of high rainfall (January to April 2016). The first two periods were represented by a predominance of canga vegetation pollen relative to forest pollen. Under dry conditions, the associations among the taxa Aparisthmium/Alchornea, Myrcia and Bellucia dichotoma were considered important for forest ecosystems, while those among Pleroma, Hyptis parkeri, Borreria and Perama carajensis were considered important for canga ecosystems. Under wet conditions, the forests were well represented by Schefflera, Anthurium lindmanianum, Pseudopiptadenia suaveolens and Glycydendron, and the most represented canga vegetation in the pollen rain were Poaceae undif., Miconia, M. acutistipula var. ferrea and Psychotria. Aparisthmium/Alchornea and Poaceae undif. Aparisthmium/Alchornea was related to periods of low water availability, and Poaceae undif. was associated with marshy or flooded environments. Thus, an increase in the influx of Poaceae undif. pollen grains was determined by variations in the extension of flooded areas, indicating an increase in the amount of rainfall and not the opposite case. Thus, future studies on vegetation reconstruction must consider modern pollen assemblages to precisely determine paleoenvironmental and paleoclimate conditions during sediment deposition.

Phenology, biometrics and fruits production of Attalea nucifera (Arecaceae) in Colombia

Attalea nucifera is a threatened palm endemic to the Magdalena River basin in Colombia. In the past its seeds were consumed by the inhabitants of the town of Guaduas, Cundinamarca, although currently its use is less frequent. To assess the productive potential of this palm, we studied its phenology, biometric parameters, and fruit productivity in a forest relict in Guaduas. Field work was carried out between April 2016 and March 2017. The reproductive cycle of this species lasted approximately 12 and a half months from bud to fruit ripening. Although bud production occurred throughout the year, it increased during periods of greatest rainfall. Flowering peaks occurred towards the end of the rainy season and fruits ripened towards the period of low rainfall. We found a positive correlation between the number of leaves in the crown and the production of reproductive structures (rs = 0.447, p = 0.004). Palms of A. nucifera produced on average 1.3 ripe infructescences per year (± 0.62 SD) with a mean of 22.4 (± 7.34 SD) fruits each. Fruit weighed 182.9 g (± 45.97 SD) on average, 5 % (9.3 g) of which corresponded to the edible nut. The reproductive cycle of A. nucifera is closely related to rainfall patterns and fruit production is low compared to other Attalea species.

Using non-systematically collected data to evaluate the conservation status of elusive species: a case study on Australia’s Oenpelli python

Abstract ContextSpecies conservation assessments require information on distribution, habitat requirements and population demography and trends. Uncertain conservation assessments limit effective planning and may lead to poor management decisions. Top-order predators generally receive considerable attention from ecologists and conservation biologists, with the notable exception of large pythons and boas. They are typically elusive and have low population densities, posing challenges for ecological research and monitoring. Ecological and demographic data are lacking for most large snake species and are generally inadequate to properly assess conservation status or to evaluate their broader ecological roles. The Oenpelli python (Simalia oenpelliensis) is Australia’s second-longest snake species, but remains one of the least-known of the world’s pythons. AimsWe sought to use non-systematically collected data from multiple sources to evaluate Oenpelli python population trends and habitat associations, and to assess its conservation status. MethodsWe identified a priori biases in data and evaluated their influences on environmental models and temporal variability in reporting patterns. We then used these findings to assess the conservation status of this species, identify knowledge gaps, and refine future survey and monitoring methods. Key resultsOenpelli python records were strongly associated with monsoon rainforest, sandstone outcrops and perennial streams, irrespective of detection biases. Total area of occupancy was estimated to be 19252km2. Detection patterns were strongly seasonal and associated with periods of low rainfall and low moonlight, informing better-targeted survey and monitoring methods with improved sensitivity. ConclusionsOenpelli pythons have a highly fragmented distribution owing to their strong association with monsoon rainforest. This habitat is likely to provide more food resources and refuge from high temperatures than are the surrounding savanna woodlands. Detection probability should improve by surveying Oenpelli pythons in September on moonless nights and following periods of high rainfall. Taking a precautionary approach, the Oenpelli python qualifies as Vulnerable under IUCN criteria, supporting its current Red List and Northern Territory Government status. ImplicationsNon-systematically collected data on poorly known species can be used to improve conservation assessments where there may otherwise be high uncertainty. The present study also highlighted the paucity of ecological knowledge of large iconic snake species globally.

What influences road mortality rates of eastern grey kangaroos in a semi-rural area?

BackgroundRoads have major ecological impacts on wildlife. Vehicle collisions most frequently impact large herbivores due to their larger home range compared to smaller animals, and higher population density compared to carnivores. Kangaroos (Macropus spp.) account for a large proportion of reported wildlife vehicle collisions that occur in N S W, Australia. We aimed to evaluate what influenced road mortality of eastern grey kangaroos (Macropus giganteus) in a temperate rural/suburban region. The location of roadkilled kangaroos found on or near two 1 km stretches of road in Richmond NSW was recorded throughout 2014 and 2015. Weather and moon phase data were recorded for the date of each roadkilled kangaroo. Transects were setup on both roads, and multiple road and landscape features, including the width of roadside, fence construction, habitat type, and distance from street lights measured at 50 m intervals. Data were analyzed to explore which landscape features and temporal factors influenced the occurrence of a roadkill hotspot.ResultsMore kangaroo road mortalities occurred during periods of low temperature and low rainfall, and these factors are likely to affect forage quality. Fewer mortalities occurred when rain was falling. A greater number of mortalities occurred during the waning gibbous phase of the lunar cycle. Significantly more road mortalities occurred a short distance from the end of a section of street lights.ConclusionsThe findings suggest that illumination influences the likelihood of kangaroo road mortalities. Large herbivores are particularly sensitive to habitat fragmentation because they need unrestricted access to large continuous habitat. Knowledge of factors that influence where and when kangaroos are most likely to cross roads can be used to inform more targeted management strategies and improve future road design and habitat connectivity to reduce the incidence of wildlife vehicle collisions.