Garden Habitats Research Articles

KEANEKARAGAMAN AVIFAUNA DIURNAL PADA KAWASAN MEMPAWAH MANGROVE PARK DAN SEKITARNYA DI DESA PASIR KABUPATEN MEMPAWAH

Avifauna is one of the animals that is easily found in various places, and is one indicator of environmental quality. Avifauna has the ability to spread seeds, help pollinate, natural predators of other animals, and others. This study aims to record the diversity of diurnal avifauna in area Mempawah Mangrove Park and its surroundings in Pasir Village Mempawah Hilir Subdistrict, Mempawah district. The research method used the Point count method, whose observation points are obtained by Purposive sampling, carried out on 9 July-9 August 2018. The results of observations were 35 species of avifauna consisting of 24 families which were divided into three habitats, in the mangrove habitat there were 18 species and 15 families, mixed garden contained 22 species and 18 families, and rice field contained 17 species and 11 families. The dominance index in the mangrove habitat is C = 0.40, mixed garden is C = 0.10 and rice is C = 0.13, indicates that no species dominates the other species, meaning the role of the avifauna species found in all three same habitat. Diversity index shows that mixed garden habitat has a higher species diversity with () = 2.66, mangrove habitat is () = 2.43 and a rice field habitat is () = 2.40, indicates that the three habitats have diversity with moderately criteria. Evenness index in mangrove habitat is (E) = 0.84, in mixed garden habitat is (E) = 0.85 and a rice field habitat is (E) = 0.85, indicates the three habitats the abundance includes evenly distributed or included in a stable community. The highest similarity index of avifauna species is between mangrove habitat and mixed garden with a percentage of 53.58%, rice field habitat with a garden with a percentage of 53.19%, and mangrove habitat with rice fields with a percentage of 38.49%. The highest similarity was between.Keywords: Avifauna, Diversity, Mempawah Mangrove Park

Research Note: Garden-owner reported habitat heterogeneity predicts plant species richness in urban gardens

Amidst ongoing urbanization and increased research on urban greenspaces, the biodiversity level of these spaces is an important variable. Attaining biodiversity estimates by asking non-expert greenspace users to assess aspects of a greenspace has a number of advantages over expert assessments (costs, sample size etc.). This article discusses an approach to such a citizen-science assessment of plant species richness using reported garden habitat heterogeneity and visually assisted reported plant species richness. We compare expert-assessed plant species richness with garden owner-generated estimates in a sample of 83 gardens. We show it is possible to predict approx. 50% of variation in plant species richness in gardens using just two visual survey questions regarding habitat heterogeneity and plant species richness.

Planting gardens to support insect pollinators.

Global insect pollinator declines have prompted habitat restoration efforts, including pollinator-friendly gardening. Gardens can provide nectar and pollen for adult insects and offer reproductive resources, such as nesting sites and caterpillar host plants. We conducted a review and meta-analysis to examine how decisions made by gardeners on plant selection and garden maintenance influence pollinator survival, abundance, and diversity. We also considered characteristics of surrounding landscapes and the impacts of pollinator natural enemies. Our results indicated that pollinators responded positively to high plant species diversity, woody vegetation, garden size, and sun exposure and negatively to the separation of garden habitats from natural sites. Within-garden features more strongly influenced pollinators than surrounding landscape factors. Growing interest in gardening for pollinators highlights the need to better understand how gardens contribute to pollinator conservation and how some garden characteristics can enhance the attractiveness and usefulness of gardens to pollinators. Further studies examining pollinator reproduction, resource acquisition, and natural enemies in gardens and comparing gardens with other restoration efforts and to natural habitats are needed to increase the value of human-made habitats for pollinators.

Predation risk shaped by habitat and landscape complexity in urban environments

Abstract Habitat loss and modification are hallmarks of anthropogenic ecosystems, but the consequences for ecosystem functioning and service provisioning often remain unclear. Understanding these links in cities is complicated by strong but fine‐scale differences in habitat structure among green space patches, and a high variance in habitat amount across urban landscapes. We used airborne laser scanning data to disentangle the effects of 3D woody habitat heterogeneity of urban home gardens, and woody habitat amount at four landscape spatial scales (50, 100, 250, and 500 m), on the predation risk of artificial sentinel prey by birds and arthropods. In both predator groups, and at all the investigated spatial scales, cross‐scale interactive effects between garden habitat heterogeneity and habitat amount in the urban landscape were the main drivers of predation. Risk of predation by birds was highest in heterogeneous garden habitats, but only in densely built urban landscapes where habitat amount was low to intermediate (10%–20%) at large spatial scales (250–500 m). It dropped independently of garden habitat heterogeneity when habitat amount became too low (<10%) at small (50–100 m) spatial scales. In contrast, risk of predation by arthropods mostly peaked in homogeneous garden habitats when habitat amount was intermediate (20%) at large spatial scales. Our findings show that the ability of urban green space patches, such as gardens, to sustain ecosystem functions in cities mainly depends on cross‐scale interactive effects with larger scale habitat amount. In birds, predation activity can increase when high patch‐scale habitat heterogeneity contrasts with reduced larger scale habitat amount, suggesting concentration effects. Yet, thresholds exist under which ecosystem functioning drops independently of habitat structure. Synthesis and applications. The potential of small‐scale interventions to enhance habitat heterogeneity (e.g., by planting native trees with understorey shrubs) for restoring ecosystem functions, such as bird predation, in urban areas is dependent on wider landscape habitat structure. Urban planning should therefore adopt a multiscale approach to sustain and restore ecosystem functions and services; a simple but still not broadly recognized finding. Airborne laser scanning is a useful tool to infer habitat structure across a hierarchy of scales in spatially heterogeneous anthropogenic ecosystems.

A Gardener's Influence on Urban Soil Quality

Gardens are hot spots for urban biodiversity and provide habitats for many plant and animal spe- cies, both above- and below-ground. Furthermore, gardens provide a wide range of ecosystem services, including carbon (C) storage and nutrient cycling. Although the soil is the foundation of sustainable gardens providing those ecosystem services, very little is known about the conseque- nces of garden management on soil quality. Here we present a comprehensive assessment of urban garden soil quality, including biotic and abiotic site characteristics combined with land-use history and garden management information in a multivariate evaluation. A set of 44 soil quality indicators was measured at 170 sites of 85 gardens in the city of Zurich, Switzerland, comprising contrastingly managed garden habitats along a gradient of urban density. Taken together, our results show that garden management was the driving factor that influenced soil quality and soil functions. Eco-physiological soil quality indices were useful to identify differences in disturbance and intensity of soil use, showing highest microbial (microbial biomass (Cmic)/soil organic carbon (SOC)) and lowest metabolic (qCO2) quotients in perennial grass sites compared to annual vegetable sites. Despite the intensity of soil disturbance in annual vegetable and flower beds, the highest endogeic earthworm biomass and diversity were found in those habitats. Whereas decomposition of green tea bags was higher in grass sites. Soil heavy metal contents varied considerably and could not be linked with garden management practices, but with spatial patterns of industry and traffic. We conclude that understanding soil quality in urban ecosystems needs multi-indicator frameworks to capture the complexity of soil characteristics and the influencing factors in space and time. This study contributes to a better understanding of urban gardens and enhances the development of sustainable soil management strategies aimed at long-term improvement of soil quality and related ecosystem services in cities.

Contribution to the Pachylaelapidae (Acari: Mesostigmata) fauna in some parts of Guilan province of Iran

A faunistic study on the family Pachylaelapidae in forest and garden habitats from some regions in Guilan province, northern Iran, was carried out during 2015–2016. The samples were taken from soil, decaying organic matter, especially humus, rotten wood, moss and plant remains. A total of 10 species, belonging to three genera, were collected and identified, among them, Onchodellus squamosus Koroleva is newly recorded from Iran. Onchodellus and Pachylaelaps grandis Koroleva were considered as the most specious genus and the most frequent species, respectively. Some morphological characters and distributions of the species in Iran are discussed herein.

An ethnobotanical survey of medicinal and edible plants of Yalo Woreda in Afar regional state, Ethiopia

BackgroundThe Afar people inhabit the sub-arid and arid part of Ethiopia. Recurrent drought and invasive encroaching plants are taking out plants that have cultural importance, and threaten the biodiversity and the associated traditional knowledge. Thus, the aim of the current study is to conduct an ethnobotanical survey and document medicinal and edible plants in Yalo Woreda in Afar regional state.MethodsA cross-sectional ethnobotanical study was carried out in eight kebeles of Yalo Woreda from October 2015 to December 2016. One hundred sixty informants were selected using purposive sampling. The data on diseases, medicinal and edible plants were collected using semi-structure interview and group discussion. The statistical methods, informant consensus factor, fidelity level, and preference ranking were conducted to analyze the data.ResultsOne hundred and six plants were reported; gender and age differences had implication on the number of plants reported by informants. The knowledge of medicinal plants among informants of each kebele was not different (p < 0.5) and was not associated in particular with the religious establishment in the kebeles (informant*kebeles, Eta square = 0.19). Family Fabaceae was the major plant species, and shrubs (44%) were dominant plants reported. Leaf (52.94%) and oral (68%) were primary plant part used for remedy preparation and route of application, respectively. The plants with low fidelity values Indigofera articulata (0.25), Cadaba farinosa (0.22), Cadaba rotundifolia (0.19), and Acalypha fruticosa (0.15) were used to treat the category of diseases with high informant consensus value (0.69). Sixteen edible plants were identified that were consumed during wet and dry seasons. Balanites aegyptiaca, Balanites rotundifolia, and Dobera glabra were ‘famine food’ that were collected and stored for years.ConclusionPeople in Yalo Woreda are more dependent on natural resources of the area for their livelihood. The threat of climatic change and encroaching invasive plants on medicinal and edible plants affects the traditional use of plants in the Yalo Woreda. The conservation of the plants in the home garden and natural habitat and integration of edible plants into agroforestry development programs in sub-arid and arid regions has to be encouraged to conserve plants of medical and economic importance.

Patterns of pollinator turnover and increasing diversity associated with urban habitats

The role of urban expansion on bee diversity is poorly understood, but it may play an important role in restructuring pollinator diversity observed in rural regions at the urban perimeter. We studied bee communities in two habitats essential for pollinators (residential gardens and semi-natural areas) at 42 sites situated at the edge of greater Montreal, Canada. Bee species richness, abundance and functional diversity all increased with urbanization in both habitat types, but gardens and semi-natural areas supported distinct bee communities with unique responses to urbanization in terms of species turnover. Compared to semi-natural sites, residential gardens supported bees that foraged from a greater number but a lower proportion of available plant species. Bees did not discriminate between exotic and indigenous plant species in either gardens or semi-natural sites and were attracted to flowers in either habitat irrespective of their origins. Protecting semi-natural ruderal areas and providing residential garden habitats for pollinators are both effective means of promoting regional bee diversity in urbanizing regions.

Landscape and Local Habitat Correlates of Lady Beetle Abundance and Species Richness in Urban Agriculture

Landscape surroundings and local habitat management affect patterns of insect biodiversity. Knowing which landscape and local factors are more important for insect species diversity informs landscape and local scale land management, yet can be challenging to disentangle. We sought to identify 1) which landscape factors surrounding, and 2) which local habitat factors within urban community gardens influence patterns in lady beetle (Coccinellidae) abundance and species richness. We assessed lady beetle abundance and taxonomic diversity, garden habitat characteristics, and the surrounding landscape composition in 19 gardens over two consecutive years. We found that the amount of natural area surrounding gardens at 3 km was the strongest correlate of abundance and species richness. Specifically, gardens surrounded by less natural area (gardens embedded in more urban landscapes) had higher lady beetle abundance and richness. In gardens embedded in landscapes with more amounts of natural land, local habitat features such as ornamental abundance and crop diversity may become more important for maintaining lady beetle abundance and richness. Our results suggest that within more urban landscapes, lady beetles may aggregate and accumulate in relatively resource-rich habitats like gardens. Thus, urban landscape quality and local habitat management may all interact to shape lady beetle communities within gardens.

Photosynthetic Performance of Invasive Vincetoxicum Species (Apocynaceae)

Knowledge of photosynthetic capacity is crucial for fully understanding a species’ invasive potential and for the development of appropriate control strategies. Although growth and reproductive data are available for the invasive swallowwort vines Vincetoxicum nigrum and V. rossicum, photosynthetic data are wanting. These herbaceous, perennial congeners were introduced from separate European ranges during the late 19th century and became invasive during the following century in the northeastern United States and southeastern Canada. Vincetoxicum nigrum has been observed growing mainly in high light environments, whereas V. rossicum occurs across a wide range of light environments, suggesting niche divergence and that different management strategies might be needed for the two species. In this work, we investigated whether the differing habitat associations of these species is reflected in their photosynthetic capacities and leaf morphology. Photosynthetic parameters and specific leaf mass were determined across a range of light environments represented by four field habitats (common garden, forest edge, old field, and forest understory) and two greenhouse environments (high and low light). In the high-light common garden habitat, V. nigrum achieved 37% higher maximum photosynthetic rates than V. rossicum, but photosynthetic performance of the two species was the same in the forest edge habitat. Additionally, species’ performance was virtually identical in high light, low light, and transitions between high and low light regimes in the greenhouse. Specific leaf mass of V. nigrum was 17% higher in the common garden and 19% higher in the greenhouse compared with V. rossicum. Both invasive Vincetoxicum spp. appear capable of growing within a broad range of light environments and their management should be similar regardless of light environment. Other explanations are required to explain the scarcity of V. nigrum in low light natural areas.

Richard Hansen and modern planting design

Richard Hansen's planting design, following garden habitats, is said to be an approach equally uniting ecology and design (Fig. 1). Common opinion understands ecological planting design as utilizing only native plants—an approach often seen as having been rooted in National Socialist ideology. This, however, is a misconception, which will be demonstrated by discussing Alwin Seifert's ideas of bodenständig (down-to-earth) planting design. Consequently, through his concept of garden habitats, Hansen implements the requirements of Bodenständigkeit (‘down-to-earthedness’). In addition to functionality, this includes in particular the integration of foreign species of plants within horticulture through the use of plant sociology. This provided Hansen with scientific backing for his planting design in the garden. His concept differs significantly from approaches of other important personalities in German planting design, such as Willy Lange, Alwin Seifert, or the subsequent Nature Garden movement of Le Roy or Urs Schwarz. To understand the originality of Hansen's theory it is necessary to discuss his use of the term Bodenständigkeit—a term relevant for the time in which he operated. Garden habitats can be discussed in the context of landscape character (as in the works of Willy Lange), or under the relevance of site conditions in the contemporary meaning of the term (soil, water, climate) as used by Hansen (Fig. 2). Although Hansen declares native plants as bodenständig, just as his teacher Tüxen did, he proclaimed that foreign plants should be introduced in the garden to create artificial plant(ed) communities, derived from the examples of natural plant associations and thereby decreasing maintenance work. Hansen conducted extensive long-term plant trials to be able to differentiate garden habitats for numerous perennial plants. Hansen's main work, Die Stauden und ihre Lebensbereiche (Perennials and Their Garden Habitats), originates from 1981; it is still in print today and was translated into English in 1993.

Garden and landscape-scale correlates of moths of differing conservation status: significant effects of urbanization and habitat diversity.

Moths are abundant and ubiquitous in vegetated terrestrial environments and are pollinators, important herbivores of wild plants, and food for birds, bats and rodents. In recent years, many once abundant and widespread species have shown sharp declines that have been cited by some as indicative of a widespread insect biodiversity crisis. Likely causes of these declines include agricultural intensification, light pollution, climate change, and urbanization; however, the real underlying cause(s) is still open to conjecture. We used data collected from the citizen science Garden Moth Scheme (GMS) to explore the spatial association between the abundance of 195 widespread British species of moth, and garden habitat and landscape features, to see if spatial habitat and landscape associations varied for species of differing conservation status. We found that associations with habitat and landscape composition were species-specific, but that there were consistent trends in species richness and total moth abundance. Gardens with more diverse and extensive microhabitats were associated with higher species richness and moth abundance; gardens near to the coast were associated with higher richness and moth abundance; and gardens in more urbanized locations were associated with lower species richness and moth abundance. The same trends were also found for species classified as increasing, declining and vulnerable under IUCN (World Conservation Union) criteria. However, vulnerable species were more strongly negatively affected by urbanization than increasing species. Two hypotheses are proposed to explain this observation: (1) that the underlying factors causing declines in vulnerable species (e.g., possibilities include fragmentation, habitat deterioration, agrochemical pollution) across Britain are the same in urban areas, but that these deleterious effects are more intense in urban areas; and/or (2) that urban areas can act as ecological traps for some vulnerable species of moth, the light drawing them in from the surrounding landscape into sub-optimal urban habitats.

Assessing the value of the Garden Moth Scheme citizen science dataset: how does light trap type affect catch?

AbstractDone well, citizen science projects can gather datasets of a size and scope far larger than would be possible using professional researchers. This study uses data gathered in Britain by the Garden Moth Scheme (GMS). Participants run garden light traps for at least 26 weeks a year and complete garden questionnaires detailing garden habitat and nearby landscape features. We used data exploration and generalised linear modelling (GLM) to investigate whether the data can be used to generate reliable research findings, testing the effect of moth light trap type on moth catch. Robinson traps, then Skinner traps, then Heath traps were found to catch the highest abundance and diversity of moths. Mercury vapour bulbs, then blended light bulbs, then actinic bulbs collected the highest abundance and diversity of moths. The GMS dataset can be used to generate useful and reliable research findings, and can be used in the future to investigate temporal and spatial trends in moth assemblage. Under international law, the use of mercury vapour bulbs will be phased out in coming years, leading to changes in the way moth assemblages are sampled. Information on the relative efficacy of different bulb types will aid the analysis of long‐term moth datasets after these changes.

Species diversity and spatial differentiation of old-valuable trees in urban Hong Kong

Heritage trees play special ecological, historical and landscape roles in cities. The officially designated old-valuable trees (OVTs) in Hong Kong, threatened by urban intensification and improper care, demand deep understanding to inform management and conservation. This study evaluated their floristic diversity, biomass structure and importance value, and spatial pattern and differentiation by districts and tree-habitats. Data analysis was assisted by detrended correspondence analysis (DCA), similarity percentage analysis (SIMPER) and other statistical tests. New indices, namely district dissimilarity index (DDI), district heterogeneity index (DHI), habitat dissimilarity index (HDI) and habitat heterogeneity index (HHI) helped to assess spatial differentiation. The 352 OVTs belonged to 70 species, 56 genera and 36 families. Ficus microcarpa dominated with maximum importance value, accompanied by only three common species. Some 22 rare and 44 solitary species denote diverse origins due to inheritance and cultivation. Moraceae and Ficus were the dominant family and genus. The oldest districts accommodated more species, trees, and unique species, whereas newer districts had notably less. DCA showed higher floristic fidelity in old districts, and three common Ficus species were ubiquitous in districts. SIMPER results showed the highest DDI and lowest DHI in the newer district. Public park and garden (PPG) habitat harbours most species, trees, and botanical uniqueness. Three Ficus species were also ubiquitous in habitats. Public housing and PPG had the highest HDI. District and habitat dissimilarities were mainly contributed by dominant and common species. Management implications with reference to preservation and enhancement of OVTs were explored, with applications for other cities.

AVIFAUNAL DIVERSITY IN A TEA PLANTATION ECOSYSTEM IN THE UP-COUNTRY OF SRI LANKA

A survey on birds was conducted at Mattakelle Tea Estate with the objective of assessing the significance of a given tea plantation ecosystem in maintaining avifaunal diversity. Seven different habitats were identified in the ecosystem namely home garden, seasonal stream, small scale reservoir, Eucalyptus forest, wetland, tea field and secondary forest. The monitoring was conducted from January to June 2010 using line transect method. 28 counts were made for each habitat. Besides, activities of birds, feeding habits and food recourses were observed.61 species of birds including 9 species of endemics and 10 species of migrants were recorded. One globally threatened species Kashmir Flycatcher (Ficedula subrubra) and 12 nationally threatened species were observed. Among the habitats, the highest species count of 62% was recorded in home garden habitat where Shannon index (H’) = 3.03 and Evenness (J) =0.46. Species diversity and the evenness of the secondary forest were comparable to tea field indicating H’= 2.86 and J=0.43; H’ =2.77 and J= 0.46 respectively. The avifaunal diversity was relatively low in the rest.The study revealed that each of the habitats provided unique niches and supported maintenance of natural diversity. Vegetation structure and the complexity of the ecosystem in tea plantations play a vital role in sustaining avifaunal diversity. Several conservation measures such as increasing plant diversity, introduction of shade trees, conduct of good agricultural practices and prevention from setting fire are recommended to protect and conserve avifaunal diversity.

The European hedgehog (Erinaceus europaeus) – A suitable reservoir for variants of Anaplasma phagocytophilum?

The European hedgehog (Erinaceus europaeus) is a common insectivore in most parts of Europe and is frequently infested by the ticks Ixodes ricinus and I. hexagonus. I. ricinus ticks have been found infected with Anaplasma phagocytophilum, an obligate intracellular bacterium, but little is known about the potential of the hedgehog as a reservoir host. In this study, the infection with A. phagocytophilum and the genetic variants involved were investigated in a captive hedgehog population which was kept in a fenced, natural grass and bush garden habitat, and also in its ticks. Additionally hedgehogs from hedgehog caretaking stations were investigated. EDTA blood and ticks were collected from the captive hedgehog population once a month from March to October 2007 and in March and April 2008. All 3 developmental stages of I. ricinus and I. hexagonus occurred on the hedgehogs. After DNA extraction, the samples were screened for A. phagocytophilum with a real-time PCR, and selected samples were further investigated with a nested PCR targeting the partial 16S rRNA gene, followed by sequencing. One hundred thirty-six out of 220 hedgehog blood samples (61.8%) from altogether 48 individuals, 413 out of 563 I. ricinus samples and 90 out of 338 I. hexagonus samples were PCR-positive. Thirty-two hedgehogs were positive more than once, most frequently twice or 3 times, but also up to 9 times. Sequencing of the partial 16S rRNA gene resulted in 6 variants, but one variant (‘A’) was the most frequent which appeared in 93.8% of the positive hedgehogs. This variant (equaling Frankonia II, GenBank AF136712) has recently been reported from human, equine, and canine granulocytic anaplasmosis cases and thus, its specific association with hedgehogs is an important finding in the epidemiology of A. phagocytophilum in Europe.The high infection rate of both hedgehogs and ticks with A. phagocytophilum and the simultaneous infestation with 2 tick species of all developmental stages suggest that the hedgehog may be a suitable reservoir for at least some variants of A. phagocytophilum.

Pulsed-field gel electrophoresis supports the presence of host-adapted Salmonella enterica subsp. enterica serovar Typhimurium strains in the British garden bird population.

Salmonellosis is a frequently diagnosed infectious disease of passerine birds in garden habitats within Great Britain with potential implications for human and domestic animal health. Postmortem examinations were performed on 1,477 garden bird carcasses of circa 50 species from England and Wales, 1999 to 2007 inclusive. Salmonellosis was confirmed in 263 adult birds of 10 passerine species in this 11-year longitudinal study. A subset of 124 fully biotyped Salmonella enterica subsp. enterica serovar Typhimurium isolates was examined using pulsed-field gel electrophoresis to investigate the hypothesis that these strains are host adapted and to determine whether this molecular technique offers greater resolution in understanding the epidemiology of Salmonella Typhimurium infection than phage typing alone. For the two most common phage types, definitive type (DT) 40 and DT56v, which together accounted for 97% (120/124) of isolates, pulsed-field gel electrophoresis groupings closely correlated with phage type with remarkably few exceptions. A high degree of genetic similarity (>90%) was observed within and between the two most common pulsed-field gel electrophoresis groups. No clustering or variation was found in the pulsed-field gel electrophoresis groupings by bird species, year, or geographical region beyond that revealed by phage typing. These findings support the hypothesis that there are currently two host-adapted Salmonella phage types, S. Typhimurium DT40 and DT56v, circulating widely in British garden birds and that the reservoir of infection is maintained within wild bird populations. Large-scale multilocus sequence typing studies are required to further investigate the epidemiology of this infection.

Gardens benefit bees and enhance pollination in intensively managed farmland

The recent loss of pollinating insects and out-crossing plants in agricultural landscapes has raised concern for the maintenance of ecosystem services. Wild bees have been shown to benefit from garden habitats in urban and suburban areas. We investigated the effects of distance from garden habitats on wild bees and seed set of a native out-crossing plant Campanula persicifolia, in intensively managed agricultural landscapes in Southern Sweden. Bee abundance and species richness, as well as plant seed set, were higher closer to gardens (<15 m) than further away (>140 m). This highlights private gardens as a landscape wide resource for pollinators but also the lack of sufficient pollination of wild plants in contemporary agricultural landscapes.

Chemical-Garden Formation, Morphology, and Composition. II. Chemical Gardens in Microgravity

We studied the growth of metal-ion silicate chemical gardens under Earth gravity (1 g) and microgravity (μg) conditions. Identical sets of reaction chambers from an automated system (the Silicate Garden Habitat or SGHab) were used in both cases. The μg experiment was performed on board the International Space Station (ISS) within a temperature-controlled setup that provided still and video images of the experiment downlinked to the ground. Calcium chloride, manganese chloride, cobalt chloride, and nickel sulfate were used as seed salts in sodium silicate solutions of several concentrations. The formation and growth of osmotic envelopes and microtubes was much slower under μg conditions. In 1 g, buoyancy forces caused tubes to grow upward, whereas a random orientation for tube growth was found under μg conditions.

Non-invasive invaders from the Caribbean: the status of Johnstone’s Whistling frog (Eleutherodactylus johnstonei) ten years after its introduction to Western French Guiana

The neotropical frog Eleutherodactylus johnstonei (Anura: Eleutherodactylidae) has been referred to as a highly invasive species on grounds of its wide distribution and is expected to extend its range significantly based on recent climate model assumptions. The frog was introduced to a number of South American mainland localities, including French Guiana. Other species of the genus have become invasive on oceanic islands such as Hawaii where they pose serious biological and economical problems. No data are available on the invasion status of E. johnstonei populations from coastal South America. Here we present the first assessment of the status of a mainland population from French Guiana 10 years after the introduction of the species. We found that the species has not spread significantly within the last ten years and so far does not exhibit a high invasion potential. Frogs were restricted to urban garden habitats showing significantly higher abundance in gardens containing ornamental potted plants. Distribution patterns were best explained by two dispersal-related factors operating at different scales: (1) distance of occupied sites to nearest population indicating short-distance active dispersal using stepping stone habitats, and (2) distance of occupied sites to shore with a distinct bimodal pattern indicating long-distance passive or jump-dispersal, most likely due to the exchange or transfer of ornamental plants. Even though past and current invasion potential can be considered low, we advocate the implementation of a regional monitoring scheme and detailed studies on biotic interactions with native fauna.