A 20-year dataset of species replacement patterns in the middle-intertidal zone of Tatoosh Island, Washington, USA

A 20‐year data set of species replacement patterns in the middle‐intertidal zone of Tatoosh Island, Washington, <scp>USA</scp>

We describe the spatial and temporal patterns in the abundance of nematode-trapping fungi and in suppression of nematodes in a coastal shrubland. A previous study at this location (Bodega Marine Reserve, Sonoma County, California) had documented a soil food chain in which an insect-parasitic nematode consumes and kills the soil-dwelling larva of the ghost moth, which otherwise consumes and kills the bush lupine; the patchy distribution of the nematode and lupine suggest the involvement of nematophagous organisms, including nematode-trapping fungi. To test our model (trapping fungi kill insect-parasitic nematodes, and therefore ghost moths persist and kill lupines at some sites), we hypothesized that sites with substantial lupine mortality would contain larger numbers of nematode-trapping fungi and would be more suppressive to nematodes than would sites with little lupine mortality. Soil was collected from eight sites (four with substantial lupine mortality and four with little lupine mortality) at 2-mo intervals for 1 yr and subjected to dilution plating and most probable number procedures. Nematode-trapping fungi detected were Arthrobotrys brochopaga, A. musiformis, A. oligospora, A. superba, Geniculifera paucispora, Hirsutella rhossiliensis, Monacrosporium cionopagum, M. doedycoides, M. eudermatum, M. parvicollis, Nematoctonus concurrens, and Stylopage sp. A. oligospora was the most abundant. Some soil samples contained large numbers of nematode-trapping fungi (as many as 695 propagules/g of soil), but sites with substantial lupine mortality did not contain larger numbers than did sites with little mortality. In a laboratory bioassay, suppression of the root-knot nematode Meloidogyne javanica was significant in 44% of the samples, but suppression was not correlated with fungal population density; moreover, soil from sites with substantial lupine mortality was less suppressive than was soil from sites with little mortality. The spatial and temporal patterns in fungal abundance and in nematode suppression, therefore, did not support our model that nematode-trapping fungi cause the patchy distribution of the insect-parasitic nematode and hence of lupine. Nevertheless, we must be conservative in rejecting the involvement of these fungi in the food chain, because methods for fungal quantification have important limitations.

Patterns of abundance across space and time, and intraspecific variation in body size, are two species attributes known to influence diet breadth and the structure of interaction networks. Yet, the relative influence of these attributes on diet breadth is often assumed to be equal among taxonomic groups, and the relationship between intraspecific variation in body size on interaction patterns is frequently neglected. We observed bee–flower interactions in multiple locations across Montana, USA, for two growing seasons and measured spatial and temporal patterns of abundance, along with interspecific and intraspecific variation in body size for prevalent species. We predicted that the association between spatial and temporal patterns of abundance and intraspecific variation in body size, and diet breadth, would be stronger for bumble bee compared to non-bumble bee species, because species with flexible diets and long activity periods can interact with more food items. Bumble bees had higher local abundance, occurred in many local communities, more intraspecific variation in body size, and longer phenophases compared to non-bumble bee species, but only local abundance and phenophase duration had a stronger positive association with the diet breadth of bumble bee compared to non-bumble bee species. Communities with a higher proportion of bumble bees also had higher intraspecific variation in body size at the network-level, and network-level intraspecific variation in body size was positively correlated with diet generalization. Our findings highlight that the association between species attributes and diet breadth changes depending on the taxonomic group, with implications for the structure of interaction networks.

We examined various measures of temporal and spatial patterns of abundance and breeding activity of Namaqua sandgrouse Pterocles namaqua (presumably mostly for P. n. furvus) in South Africa. Bird-atlas maps indicating reporting-rates and extensive-counts showed that the majority of Namaqua sandgrouse concentrate in Bushmanland, in the north-western Cape Province, from December to March. From April to July the sandgrouse move north and east of Bushmanland and apparently return to Bushmanland from August to November. This west-east movement occurs at a relatively constant rate of 30-50 km per month. Only 15% of the sandgrouse ringed at an estate within the eastern part of this species range returned the following winter. Follicle diameter and brood-patch measurements increased significantly from July to August, at the time when the majority of birds leave the estate. Belly-soaking was more prevalent in early summer in Bushmanland than in any season in the east. South African populations of Namaqua sandgrouse are partial migrants which breed primarily in early summer (October - November) in Bushmanland.

Louisiana’s estuaries and coastal waters play an important role in providing habitat for several estuarine-dependent species and also serve as a nursery for the juveniles of several other species. The current rate of land loss in Louisiana and the decline of estuarine-dependent species force us to improve our understanding of the recruitment of these species into Louisiana’s estuaries. Habitat suitabilities were developed for several fish species of concern (SOC) and other estuarine-dependent species across three environmental gradients, abundance patterns were developed for seasons, five-year intervals, and coastal study areas (CSAs). Chi-square analyses and ANOVAs were then used to test for differences in the suitability patterns and abundance patterns, respectively. The pipefish species, chain pipefish, Syngnathus louisianae (SOC) and gulf pipefish, Syngnathus scovelli, had significantly different suitability patterns for all three environmental variables. Chain pipefish suitability patterns were significantly different for all three variables, whereas, gulf pipefish only had strong patterns for salinity and Secchi depth. The pipefishes also had different temporal and spatial abundance patterns. The two goby species, violet goby, Gobioides broussonnetii (SOC) and sharptail goby, Gobionellus hastatus, had similar suitability patterns for all three environmental variables, but for sharptail goby did not have a strong salinity suitability pattern. They also had similar seasonal abundance patterns with peaks during the spring months. The three SOC fundulids, diamond killifish, Adinia xenica, bayou killifish, Fundulus pulvereus, and saltmarsh topminnow, Fundulus jenkinsi, shared similar, strong patterns of suitability for temperature and salinity. For Secchi depth, only diamond killifish and bayou killifish had strong suitability patterns. All three species also shared seasonal abundance patterns with peaks in the winter, and spatial abundance patterns with peaks in the central CSAs. The two candidate SOCs, Atlantic threadfin, Polydactylus octonemus and southern puffer, Sphoeroides nephelus, were chosen for further analyses based on their declining annual abundances. They did not have any similar temporal or spatial abundance patterns. The two species had strong suitability patterns for all three environmental variables; however, they did not share any similar patterns. The strong suitability patterns suggest that some of the environmental variables effect habitat selection for several of these species.

Anthropogenic CO(2) is reducing the pH and altering the carbonate chemistry of seawater, with repercussions for marine organisms and ecosystems. Current research suggests that calcification will decrease in many species, but compelling evidence of impaired functional performance of calcium carbonate structures is sparse, particularly in key species. Here we demonstrate that ocean acidification markedly degrades the mechanical integrity of larval shells in the mussel Mytilus californianus, a critical community member on rocky shores throughout the northeastern Pacific. Larvae cultured in seawater containing CO(2) concentrations expected by the year 2100 (540 or 970 ppm) precipitated weaker, thinner and smaller shells than individuals raised under present-day seawater conditions (380 ppm), and also exhibited lower tissue mass. Under a scenario where mussel larvae exposed to different CO(2) levels develop at similar rates, these trends suggest a suite of potential consequences, including an exacerbated vulnerability of new settlers to crushing and drilling attacks by predators; poorer larval condition, causing increased energetic stress during metamorphosis; and greater risks from desiccation at low tide due to shifts in shell area to body mass ratios. Under an alternative scenario where responses derive exclusively from slowed development, with impacted individuals reaching identical milestones in shell strength and size by settlement, a lengthened larval phase could increase exposure to high planktonic mortality rates. In either case, because early life stages operate as population bottlenecks, driving general patterns of distribution and abundance, the ecological success of this vital species may be tied to how ocean acidification proceeds in coming decades.

All over the world, pollinators are threatened by land‐use change involving degradation of seminatural habitats or conversion into agricultural land. Such disturbance often leads to lowered pollinator abundance and/or diversity, which might reduce crop yield in adjacent agricultural areas. For West Africa, changes in bee communities across disturbance gradients from savanna to agricultural land are mainly unknown. In this study, we monitored for the impact of human disturbance on bee communities in savanna and crop fields. We chose three savanna areas of varying disturbance intensity (low, medium, and high) in the South Sudanian zone of Burkina Faso, based on land‐use/land cover data via Landsat images, and selected nearby cotton and sesame fields. During 21 months covering two rainy and two dry seasons in 2014 and 2015, we captured bees using pan traps. Spatial and temporal patterns of bee species abundance, richness, evenness and community structure were assessed. In total, 35,469 bee specimens were caught on 12 savanna sites and 22 fields, comprising 97 species of 32 genera. Bee abundance was highest at intermediate disturbance in the rainy season. Species richness and evenness did not differ significantly. Bee communities at medium and highly disturbed savanna sites comprised only subsets of those at low disturbed sites. An across‐habitat spillover of bees (mostly abundant social bee species) from savanna into crop fields was observed during the rainy season when crops are mass‐flowering, whereas most savanna plants are not in bloom. Despite disturbance intensification, our findings suggest that wild bee communities can persist in anthropogenic landscapes and that some species even benefitted disproportionally. West African areas of crop production such as for cotton and sesame may serve as important food resources for bee species in times when resources in the savanna are scarce and receive at the same time considerable pollination service.

Spatial and temporal patterns in bacterial abundance, production and viral infection in a temporarily open/closed southern African estuary

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 341:165-175 (2007) - doi:10.3354/meps341165 Spatial and temporal patterns of abundance and recruitment of ghost shrimp Trypaea australiensis across hierarchical scales in south-eastern Australia Douglas Rotherham1,2,*, R. J. West1 1School of Biological Sciences, University of Wollongong, New South Wales 2522, Australia 2Present address: NSW Department of Primary Industries, Cronulla Fisheries Research Centre, PO Box 21, Cronulla, New South Wales 2230, Australia *Email: douglas.rotherham@dpi.nsw.gov.au ABSTRACT: Spatial and temporal variation in abundance and recruitment of burrowing ghost shrimp Trypaea australiensis was examined across 3 south-eastern Australian estuaries using a hierarchical sampling design, over a 2 yr period. We tested the hypothesis that abundances of shrimp were different between plots (10s to 100s of metres apart), sites within estuaries (kilometres apart), estuaries (100s of kilometres apart) and through time. More frequent sampling at 1 site also examined temporal variation at scales of months, seasons and years. Another aim was to investigate the reliability of using counts of burrow openings to indirectly measure the relative abundance of T. australiensis. Significant and interactive variability was detected at the scale of plots for the mean numbers of shrimp and recruits. Components of variation, however, suggested there was patchiness in abundance at all spatial scales within estuaries, particularly between replicates separated by metres. Indeed, between-replicate variance was greater than for any of the temporal scales examined. Despite this small-scale patchiness, patterns of abundance and recruitment were generally consistent across broad geographic areas. Numbers of shrimp generally increased throughout spring and summer periods, and recruitment also occurred during these times. The patterns of variation observed in this study highlight the importance of including appropriate scales of sampling in future monitoring studies of T. australiensis and in experiments concerned with detecting the effects of bait harvesting on populations of shrimp. We also conclude that counting burrow openings is not a reliable predictor of the relative abundance of T. australiensis. KEY WORDS: Spatial variation · Temporal variation · Patchiness · Bait harvesting · Yabby pump · Estuaries · New South Wales Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 341. Online publication date: July 04, 2007 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2007 Inter-Research.

Ocean warming is altering the biogeographical distribution of marine organisms. In the tropics, rising sea surface temperatures are restructuring coral reef communities with sensitive species being lost. At the biogeographical divide between temperate and tropical communities, warming is causing macroalgal forest loss and the spread of tropical corals, fishes and other species, termed "tropicalization". A lack of field research into the combined effects of warming and ocean acidification means there is a gap in our ability to understand and plan for changes in coastal ecosystems. Here, we focus on the tropicalization trajectory of temperate marine ecosystems becoming coral-dominated systems. We conducted field surveys and in situ transplants at natural analogues for present and future conditions under (i) ocean warming and (ii) both ocean warming and acidification at a transition zone between kelp and coral-dominated ecosystems. We show that increased herbivory by warm-water fishes exacerbates kelp forest loss and that ocean acidification negates any benefits of warming for range extending tropical corals growth and physiology at temperate latitudes. Our data show that, as the combined effects of ocean acidification and warming ratchet up, marine coastal ecosystems lose kelp forests but do not gain scleractinian corals. Ocean acidification plus warming leads to overall habitat loss and a shift to simple turf-dominated ecosystems, rather than the complex coral-dominated tropicalized systems often seen with warming alone. Simplification of marine habitats by increased CO2 levels cascades through the ecosystem and could have severe consequences for the provision of goods and services.

The spatial and temporal patterns of abundance of 8 species of chiton found under boulders were documented at sites in the mid- and low-shore regions of an extensive boulder-field in the Long Reef Aquatic Reserve. The mean number of species and mean densities of Ischnochiton australis (Sowerby , 1840), Ischnochiton elongates (Blainville, 1825), Ischnochiton versicolor (Sowerby, 1840), Cryptoplax mystica (Iredale & Hull , 1925), Callistochiton antiquus (Reeve, 1847), Ischnochiton smaragdinus (Angus, 1894) and Acanthochiton spp. did not vary through time during the 6 month study, conducted over the autumn and winter months. However, their abundances varied at small (areas 3 m apart) and large (sites 60 m apart) spatial scales in the mid- and low-shore regions. Abundances ranged between 0 and 28 individuals 1000 cm-2 of boulder surface over the study period. Relationships between the abundances, sizes and numbers of species and the size of the boulder and/or the underlying sediments were rare, contrasting with suggestions made in early taxonomic studies. However, the sizes of I. australis in the low-shore and I. elongatus in the mid-shore were positively correlated with boulder size and the density of I. elongatus was positively correlated with the proportion of fine grained sediment. A manipulative field experiment was done to examine possible sampling-induced changes in abundances. The mean number of species, total number of individuals and mean densities of Ischnochiton australis, Ischnochiton elongatus, Ischnochiton versicolor all declined following the overturning of boulders. The experiment also showed that despite the alterations to the habitat caused by our sampling, the abundances of the under-boulder chitons were not significantly altered . Therefore our data documenting patterns of abundance in space and time were not confounded by sampling-induced disturbance.

Temporal and Spatial Patterns of Abundance of the Chydoridae (Cladocera) in Lake Itasca, Minnesota

Spatial and temporal variations in the abundance of young-of-the-year channel catfish Ictalurus punctatus were determined over 3 years based on 154 trawls taken from Navigation Pool 7 of the upper Mississippi River. No significant spatial patterns in abundance or length offish in the catch were found in seven poolwide surveys of the main channel. However, high variation among replicates existed. Temporal patterns in abundance and length-frequency distributions varied among the study years. Seasonal catch curves were similar in 1984 and 1986, although offset due to earlier spawning in 1986. Spawning appeared to have been protracted in both years, based on analyses of back-calculated dates of spawn and length-frequency patterns of young. Sixty to seventy percent more young were produced in 1985, when spawning occurred over a shorter period of time and a more uniformly sized year class was produced. These annual variations in year-class characteristics are hypothesized to have resulted in part from ...

We studied spatial and temporal patterns of abundance of Ctenus amphora, C. crulsi, C. manauara and C. villasboasi, four syntopic species of medium-to-large sized wandering spiders that forage on the ground in a neotropical rainforest. We found temporal variation, apparently seasonal, in abundance for two of the four species. The four species are sympatric in the study area, but with very distinct spatial patterns of abundance. Ctenus amphora was more abundant in areas with sandy soil but are also common on clay soils, C. manauara and C. crulsi are the dominant species in areas with clay soil and are infrequent in sandy soils, and C. villasboasi had a more homogenous abundance in the study area. Previous studies suggested that a predator, army ants, could have an important impact on the abundance of these spiders. We estimated the frequency of attacks by army ants using pitfall traps in sandy and clay soil areas. The estimated probability of attack by army ants was higher in areas with clay soil (92% per 3 months), where all species are frequently found, than in sandy soil areas (21%), where C. crulsi and C. manauara were almost absent. However, it is still not clear if predation by army ants is a key factor that facilitates coexistence in clay soils, and this factor can not explain the difference on the dominant species between areas with different soil types. We also discuss the description of spatial patterns of abundance as a simple, but powerful, tool seldom used for preliminary studies on the coexistence of spiders.

One of the most popular approaches for investigating the roles of niche and neutral processes driving metacommunity patterns consists of partitioning variation in species data into environmental and spatial components. The logic is that the distance decay of similarity in communities is expected under neutral models. However, because environmental variation is often spatially structured, the decay could also be attributed to environmental factors that are missing from the analysis. Here, we use a spatial autocorrelation analysis protocol, previously developed to detect isolation‐by‐distance in allele frequencies, to evaluate patterns of species abundances under neutral dynamics. We show that this protocol can be linked with variation partitioning analyses. Moreover, in an attempt to test the neutral model, we derive three predictions to be applied both to original species abundances and to abundances predicted by a pure spatial model species abundances will be uncorrelated; Moran's I correlograms will reveal similar short‐distance autocorrelation patterns; an increasing degree of non‐neutrality will tend to generate patterns of correlation among abundances within groups of species with similar correlograms (i.e. within species with neutral and non‐neutral dynamics). We illustrate our protocol by analyzing spatial patterns in abundance of 28 terrestrially breeding anuran species from Central Amazonia. We recommend that researchers should investigate spatial autocorrelation patterns of abundances predicted by pure spatial models to identify similar patterns of spatial autocorrelation at short distances and lack of correlation between species abundances. Therefore, the hypothesis that spatial patterns in abundances are primarily due to pure neutral dynamics (rather than to missing spatiallystructured environmental factors) can be confirmed after taking environmental variables into account.