摘要:

AbstractAmphibians are the most threatened vertebrate taxon of modern times. Baseline data and affordable methods to monitor populations are absent for manyAustralian frog species. Furthermore, some species are visually cryptic, and detection often relies upon male advertisement calls. Imperfect detection rates impede our ability to assess the status of populations over time. Understanding the factors that influence calling is essential to inform the timing of survey effort and increase survey efficiency. Automated recording systems offer considerable potential to determine calling phenology and establish the relationship between calling and abiotic factors. The mountain frogs (Philoria Myobatrachidae) of theGondwana rainforests are considered susceptible to climate change impacts, such as shifts in the timing of calling. In order to describe the calling phenology ofPhiloria richmondensis,commercially available automated recording systems were deployed at five locations, and over 5000 h of sound recordings were captured and analysed. Peak calling activity occurred during morning and evening periods in the austral spring. Ambient temperature was found to significantly contribute to the probability of a call occurring, with the highest frequency of calls recorded occurring between 15°C and 16°C, and there was a negative relationship between precipitation and calling activity. The results allow future surveys to be better targeted and provide a benchmark with which to detect changes in calling phenology over

ISSN:1442-9985    

DOI:10.1111/aec.12228

年代:2015

数据来源: WILEY

摘要:

AbstractThe process of habitat fragmentation results in the breaking apart of originally continuous habitats, causing multiple changes in biotic and abiotic interactions. Alterations in resource availability and in mutualistic and antagonistic plant–animal interactions may impact plant offspring quantity and quality. Currently, several old fragmented systems evidence a process of flora homogenization, where shade‐tolerant species are replaced by pioneer light‐demanding species. Notably, the relationship between quantity and quality parameters of plant offspring production and the successful recruitment of pioneer species in fragmented forests has been poorly explored. Here, we assess population size, sapling recruitment and offspring performance of one of the most widespread tree species of subtropicalSouthAmerica, the native pioneerAcacia caven(Fabaceae). Population size of adults and saplings increased from small to continuous forests, whereas the sapling recruitment per adult tree (sapling/adult ratio) showed no significant differences among forests of different size. Seedling performance was negatively related to forest area and population size, implying potential superior competitive ability of seedlings produced in smaller populations compared to larger ones. Our results show thatA. cavenis resilient to habitat fragmentation effects, which may be ascribed to a set of advantageous ecological traits such as outcrossing, massive flowering, generalist pollination, drought resistance, rapid growth and re‐sprouting. Thus, this pioneer tree benefits from the availability of vacant sites and resources released by declining plant populations of other species, eventually becoming the dominant species in fragmented habitats. Pioneer native plant species with ecological traits such asA. cavenmay represent the silent successful survivors and new colonizers of fragmented habitats, the ubiquitous landscapes of

ISSN:1442-9985    

DOI:10.1111/aec.12230

年代:2015

数据来源: WILEY

摘要:

AbstractCold adapted plants, such as cushion plants, may be particularly sensitive to climate warming because of their compact growth form and high branch density. In the oceanic southern hemisphere, cushion communities tend to have large range distributions at low latitudes (sea level to low alpine), thus providing an opportunity to test the effects of temperature on plant morphology and reproduction across gradients. UsingDonatia novae‐zelandiaeas a model species, we compared the leaf morphology, reproduction and responses to warming. Two low‐alpine sites (Maungatua (880 m a.s.l.),BlueMountains (1000 m a.s.l.)) and two sea‐level sites (Waituna 1 (0 m a.s.l.),Waituna 2 (0 m a.s.l.)) inSouthIsland,NewZealand were used.Donatia novae‐zelandiaecushions differed significantly between the high‐elevation and sea‐level sites both morphologically and in terms of reproduction. High‐elevation cushions produced more flowers (threefold more flowers per plant) and seeds (sevenfold more seeds per capsule) than at sea level, but leaves were larger at sea level (in length and specific leaf area). The cushions were also twice as compact at the high‐elevation sites. After two growing seasons of artificial warming, seed production (35%), leaf length (7%) and width (13%), and specific leaf area (63%) significantly decreased inD. novae‐zelandiaeplants; flower production was not significantly affected. Cushion plant morphology and reproduction were significantly affected by environmental drivers at their establishment sites, but all populations responded negatively to artificial warming of 1–3°C. Many cushion plants are considered keystone species because of their propensity to facilitate the growth and establishment of other plant species, the inferred negative effects of global warming on cushion plant species may have a cascading effec

ISSN:1442-9985    

DOI:10.1111/aec.12231

年代:2015

数据来源: WILEY

摘要:

AbstractEcological theory predicts that species with narrow niche requirements (habitat specialists) are more vulnerable to anthropocentric disturbances than those with broad niche requirements (habitat generalists). Hence, understanding a species ecological niche and guild membership would serve as a valuable management tool for providinga prioriassessments of a species extinction risk. It also would help to forecast a species capacity to respond to land use change, as what might be expected to occur under financial incentive schemes to improve threatened ecological vegetation communities. However, basic natural history information is lacking for many terrestrial species, particularly reptiles in temperate regions of the world. To overcome this limitation, we collated 3527 reptile observations from 52 species across an endangered woodland ecoregion in south‐easternAustralia and examined ecological niche breadth and microhabitat guild structure. We found 30% of species had low ecological niche values and were classified as habitat specialists associated with large eucalypt trees, woody debris, surface rock or rocky outcrops. Cluster analysis separated species into six broad guilds based on microhabitat similarity. Approximately 80% of species belonged to guilds associated with old growth vegetation attributes or non‐renewable litho‐resources such as surface rock or rocky outcrops. Our results suggest that agri‐environment schemes that focus purely on grazing management are unlikely to provide immediate benefits to broad suites of reptiles associated with old growth vegetation and litho‐resources. Our classification scheme will be useful for identifying reptile species that are potentially vulnerable to anthropocentric disturbances and may require alternative strategies for improving habitat suitability and reptile conservation outcomes in grassy woodland e

ISSN:1442-9985    

DOI:10.1111/aec.12232

年代:2015

数据来源: WILEY

摘要:

AbstractMelaleucaspecies occupy varied habitats acrossAustralia with 16 members of the genus occurring in theSydney district including the rare speciesMelaleuca deanei F. Muell. Little is known of their germination and recruitment requirements. This paper reports on experiments assessing the effects of temperature, water potential, fire cues, light and shade levels on germination in four species ofMelaleucanative to theSydney region. For the shade experiment, seedling survival at 12 months is also reported. The experiments tested the hypothesis thatM. deanei, which exhibits few seedlings in the field, has limited seedling recruitment because of its particular requirements for germination and establishment. Further, that it differs in these requirements from three common congenerics:M. nodosa(Sol exGaertn.)Sm.,M. thymifolia Sm. andM. styphelioides Sm. Results indicate thatM. deaneihas a substantially similar temperature and water potential range for germination to the common congeners from 15 to 35°C, and 0 to −0.65 ψ.Melaleuca nodosadisplayed the broadest regeneration niche on all factors assessed. Germination ofM. styphelioideswas significantly reduced in the dark andM. styphelioidesandM. deaneiwere most sensitive to shade in the seedling establishment/post‐germination phase.Melaleuca deaneihad significantly larger seed that was slower to germinate in all experiments. Germination of the four species was unaffected by the application of heat and smoke. The substantially similar germination parameters exhibited by the four species, despite differences in habitat, may reflect their close phylogenetic affinities. The effects of fire on stimulating seed release from the canopy, the high‐light environment post‐fire together with adequate follow‐up rainfall may all be critical in se

ISSN:1442-9985    

DOI:10.1111/aec.12233

年代:2015

数据来源: WILEY

摘要:

AbstractLepidium castellanum,L. juvencumandL. oleraceumare threatened coastal cresses endemic toNewZealand. These three species were selfed and interspecific hybrids generated for examination of hybrid fitness and inbreeding depression. In controlled glasshouse experiments, the interspecific hybrids and selfed progeny were inoculated with a strain of the introduced Turnip mosaic virus (TuMV) previously isolated from wild populations ofL. aegrum. Experiments tested the hypothesis that heterosis in the interspecific hybrids provides a gain inTuMVresistance in comparison to selfed plants. We show that interspecific hybrids of three genetically distinct species ofLepidiumincreased plant performance and reduced susceptibility to the effects of theTuMV. We suggest that interspecific hybridization could be implemented as a conservation management strategy and that a broader outlook may be required to mitigate the negative impacts of introduced pathogens on threatened sp

ISSN:1442-9985    

DOI:10.1111/aec.12234

年代:2015

数据来源: WILEY

摘要:

AbstractWe investigated patterns of prevalence and intensity of gastrointestinal nematode infections in a tropical natricine snake, the keelback (Tropidonophis mairii). Ninety‐eight per cent of keelbacks were infected withTanqua anomala(Gnathostomidae), with infection intensities of up to 243 worms per snake. Infection withT. anomalacaused severe inflammation of stomach mucosa and submucosa at the sites of parasite attachment and encystment. Nonetheless, we did not detect detrimental effects of nematode infection on measures of fitness among wild or captive snakes. Snakes with heavier nematode infections had higher body condition scores than less‐infected individuals. Deworming captive snakes had no measurable effect on their growth rate, body condition or locomotor performance. In combination with an earlier study on blood‐dwelling hepatozoons, our work suggests that keelbacks have a high tolerance to parasites. The ‘fast‐pace’ life history and short lifespan of these snakes may make it beneficial for them to tolerate infection, rather than expend energy on resisting

ISSN:1442-9985    

DOI:10.1111/aec.12235

年代:2015

数据来源: WILEY

摘要:

AbstractThe allochthonous detritus that accumulates in the substrate of streams is used by aquatic invertebrate shredders for shelter and food. Shredders are considered rare in tropical systems, and little information is available about the role of density effects and predation risk (associated with the perception of predators by prey) in relationship to the resources used by these organisms. The aim of this study was to examine experimentally the effects of increased predation risk and of the density ofPhylloicussp. (i.e. of two types of biological relationships) on the processing of the leaf litter ofNectandra megapotamica(Spreng.)Mez.Phylloicussp. can use leaf litter for case building and as a food resource. The density effect was measured using four treatments that differed only in the number of individuals (one, two, three or four). A second experiment with five treatments was performed to test the risk of non‐lethal predation on detritus consumption (shelter and food) byPhylloicussp. (T1:Caddisfly;T2:Mayfly;T3:Astyanax sp./fish;T4:Damselflies;T5:Stonefly). A singlePhylloicusand one other organism (a potential predator blocked with 0.5 mm fine mesh) were placed in each tank (0.002 m3volume). We observed a negative effect of density on per capita litter consumption (experiment 1). The low density ofPhylloicusmay be a natural factor that decreases intraspecific competition. In the presence of fish,Phylloicusshowed the lowest amount of litter processing observed in the experiment, indicating top‐down control (experiment 2). In treatments that involved the presence of invertebrates (non‐predatory and predatory),Phylloicusshowed the highest amount and an intermediate amount of leaf litter processing, respectively (experiment 2). This observation also suggests that the predation effect is more probable for specific predator–prey pairs. Population density and predation risk inPhylloicusmay be important factors controlling leaf litter

ISSN:1442-9985    

DOI:10.1111/aec.12236

年代:2015

数据来源: WILEY

摘要:

AbstractTheNewZealand alpine flora displays a range of unusual characteristics compared with other alpine floras, in particular the high frequency of species with small white flowers. The presence of both white and bright purple flowers on the same plant in theNewZealand alpine annual creeping eyebright (Euphrasia dyeri Wettst.) provides an ideal opportunity to investigate the significance of flower colour in an environment where coloured flowers are rare. The relationships among flower age, gender phase, reward availability and petal colour were assessed in natural populations ofE. dyeri. The effect of pollination on flower colour was tested using hand pollination of bagged flowers. Direct observations and videos of flowers were used to assess patterns of flower visitation by native and introduced pollinators. Unpollinated whiteE. dyeriflowers changed from white to purple within 6 days. However, pollination of white flowers triggered a significantly faster colour change, typically within 1–2 days. White flowers had receptive stigmas, large amounts of lipid‐rich pollen and small amounts of nectar, whereas stigmas of purple flowers are not receptive and flowers did not provide pollen or nectar rewards. Flowers were mainly visited by native syrphid flies. Both native syrphids and introducedBombusbees showed a marked avoidance of purple flowers, tending to preferentially visit white flowers. Our study suggests that flower colour change from white to bright purple inE. dyerifunctions to direct pollinators to rewarding, receptive flowers. As manyEuphrasia L. species are described as having variably coloured flowers, this mechanism may be more widespread in the genus. Furthermore, our results add to the growing evidence that the dominance of white flowers in theNewZealand alpine is not simply due to a lack of colour discrimination amon

ISSN:1442-9985    

DOI:10.1111/aec.12238

年代:2015

数据来源: WILEY

摘要:

AbstractNitrogen and phosphorus are the main elements limiting net primary production in terrestrial ecosystems. When growing in nutrient‐poor soils, plants develop physiological mechanisms to conserve nutrients, such as reabsorbing elements from senescing foliage (i.e. nutrient retranslocation). We investigated the changes in soilNandPin post‐fire succession in temperate rainforests of southernChile. In this area, forest recovery often leads to spatially scattered, discrete regeneration with patches varying in age, area, species richness and tree cover, representing different degrees of recovery from disturbance. We hypothesized that soil nutrient concentrations should differ among tree regenerating patches depending on the progress of forest regeneration and that nutrient resorption should increase over time as colonizing trees respond to limited soil nutrients. To evaluate these hypotheses, we sampled 40 regeneration patches in an area of 5 ha, spanning a broad range of vegetation complexity, and collected soil, tree foliage and litter samples to determineNandPconcentrations. Nutrient concentrations in leaf litter were interpreted as nutrient resorption proficiency. We found that soilPwas negatively correlated with all the indicators of successional progress, whereas total soilNwas independent of the successional progress. FoliarNandPwere unrelated to soil nutrient concentrations; however, litterNwas negatively related to soilN, and litterPwas positively related with soilP. Finally, foliarN:Pratios ranged from 16 to 25, which suggests thatPlimitation can hamper post‐fire regeneration. We provide evidence that after human‐induced fires, succession in temperate forests ofChile can become nutrient limited and that high nutrient retranslocation is a key nutrient conservation strategy for regenerating tree co

ISSN:1442-9985    

DOI:10.1111/aec.12239

年代:2015

数据来源: WILEY