Environmental factors affecting the standing crop of foraminifera in sublittoral and psammolittoral communities of a Long Island salt marsh

Representative samples from the epiphytic and psammolittoral communities were made during the summer of 1968 in North Sea Harbor, Southampton, Long Island, USA. In the epiphytic communities, the foraminifera were very patchy; 2.6% of the total samples accounted for 56.4% of the total foraminifera collected. The standing crop and species composition of the foraminifera changed throughout the summer. Two seasonal peaks were observed in the epiphytes. In early summer Protelphidium tisburyensis was the dominant form. In late July and August Elphidium incertum was dominant. Taken as a whole over the entire summer, the following species comprised the epiphytic foraminiferan community: Elphidium incertum (46.63%); Protelphidium tisburyensis (25.64%); Ammotium salsum (9.88%); Elphidium clavatum (6.74%); E. translucens (3.47%); Ammonia beccarii (2.83%); Ammobaculites dilatatus (2.08%); Trochammina inflata (1.8%); Elphidium advenum (< 1%); E. galvestonense (< 1%); E. gunteri (< 1%); Quinqueloculina lata (< 1%); Q. seminulum (< 1%) and Trochammina macrescens (< 1%). Although fewer species were found, many more foraminifera live in the benthos than in the epiphytic community. Taken as a whole, over the entire summer, the following species comprised the foraminifera in the psammolittoral community: Trochammina inflata (49.6%); Elphidium incertum (31.8%); Ammotium salsum (10.9%); Quinqueloculina seminulum (4.2%); Elphidium sp. (1.5); Protelphidium tisburyensis (0.9%); Ammonia beccarii (0.7%); Elphidium clavatum (< 0.1%); and E. translucens (< 0.1%). Three species, Ammotium salsum, Elphidium incertum and Trochammina inflata bloomed successively in the psammolittoral community. The distribution of the latter two species was correlated with the vertical and horizontal changes of grain size; Elphidium incertum distribution clustered around a median grain size of 0.1 mm, whereas Trochammina inflata clustered around a median grain size of 0.46 mm. The sediments were sampled both at high and low tide. No evidence was obtained to suggest migration of foraminifera through the sediments as a function of tidal cycle. Horizontal distribution of the foraminifera in the marsh was correlated with the flow patterns of very small rivulets in the study area. With respect to many species of foraminifera, the overlying epiphytic communities are not continuous with the psammolittoral communities below them in the water column. Protelphidium tisburyensis was an early summer dominant epiphyte, but was rare in the psammolittoral communities. Trochammina inflata, on the other hand, was dominant in the coarser, deeper sediments and was rare in the epiphytic community. Elphidium incertum is presumably a generalist species. It formed half the foraminiferan population throughout the water column. Ammotium salsum was also abundant in both communities.Supported by US AEC Contract AT (30-1) 3995. Ref. No. NYO 3995-16.Summarized from a thesis submitted by N. J. Matera in partial fulfillment of the requirements of Master of Arts at The City College of New York.University Institute of Oceanography of CUNY, Contribution No. 1.     

Species Imperilment and Spatial Patterns of Development in the United States

Abstract:  Conservation biologists and others hypothesize that humankind's "ecological footprint" is affected not only by the sheer intensity of human activity but also by its spatial arrangement. We used a multivariate statistical model and state-level data to evaluate correlations between species imperilment and the level and spatial distribution of human settlement and infrastructure development in the United States. The level of human activity—measured by the number of people and households, incidence of roads, and intensity of nighttime lights—was significantly correlated with the ecological imperilment of species. Our regression models consistently showed that a 1% increase in the level of human activity across the United States was associated with about a 0.25% increase in the proportion of plant and animal species considered at risk of extinction by The Nature Conservancy. The distribution of human activity did not affect species imperilment. Our results point to rising levels of human activity—and not some particular (e.g., sprawling) distribution of human activity—as the most relevant anthropogenic factor explaining biodiversity loss in the United States.     

Patch Mosaic Burning for Biodiversity Conservation: a Critique of the Pyrodiversity Paradigm

Abstract:  Fire management is increasingly focusing on introducing heterogeneity in burning patterns under the assumption that "pyrodiversity begets biodiversity." This concept has been formalized as patch mosaic burning (PMB), in which fire is manipulated to create a mosaic of patches representative of a range of fire histories to generate heterogeneity across space and time. Although PMB is an intuitively appealing concept, it has received little critical analysis. Thus we examined ecosystems where PMB has received the most attention and has been the most extensively implemented: tropical and subtropical savannas of Australia and Africa. We identified serious shortcomings of PMB: the ecological significance of different burning patterns remains unknown and details of desired fire mosaics remain unspecified. This has led to fire-management plans based on pyrodiversity rhetoric that lacks substance in terms of operational guidelines and capacity for meaningful evaluation. We also suggest that not all fire patterns are ecologically meaningful: this seems particularly true for the highly fire-prone savannas of Australia and South Africa. We argue that biodiversity-needs-pyrodiversity advocacy needs to be replaced with a more critical consideration of the levels of pyrodiversity needed for biodiversity and greater attention to operational guidelines for its implementation.     

PERFORMANCE AND PERSISTENCE OF GREEN FLUORESCENT PROTEIN （gfp） MARKED AZOTOBACTER CHROOCOCCUM IN STERILIZED AND UNSTERILIZED WHEAT RHIZOSPHERIC SOIL

ThepracticaluseofAzotobacterchroococcumasbiofertilizer hasbeenincreasinglyidentifiedinrecentyears.Oftentheefficacy ofthesebacteriaisassessedonthebasisofcropresponseswithout knowingthesurvival,persistenceandcompetitiveabilityofthein troducedstrain.Inoculat…     

Population genetics of the swimming crab<Emphasis Type="Italic"> Callinectes bellicosus</Emphasis> (Brachyura: Portunidae) from the eastern Pacific Ocean

The population genetics and historical demography of the swimming crab Callinectes bellicosus from the eastern Pacific were assessed using mitochondrial DNA (mtDNA) sequences from portions of the cytochrome c oxidase subunit I (COI) and cytochrome b (Cytb) genes. Analysis of molecular variance of sequence data from crabs collected from nine localities, ranging from the upper to lower Gulf of California and the outer coast of the Baja California peninsula, revealed an absence of population structure, suggesting a high level of gene flow over a wide geographic area. Maximum-likelihood estimates of long-term effective population size obtained with the program FLUCTUATE, in addition to highly significant values obtained from neutrality tests (Tajimas D, Fu and Lis D, and Fus F_S) and mismatch analysis, are consistent with a population expansion dating to the Pleistocene epoch. Phylogenetic analysis of C. bellicosus sequences using both neighbor-joining and Bayesian methods revealed a widely distributed subclade (clade II) cryptically embedded at low frequency in the main (clade I) population. Although sequence divergence between the two clades was low (1.1% COI; 0.6% Cytb), statistical support for the split was high. The Kimura-2-parameter genetic distance between C. bellicosus and the sympatric and morphologically similar C. arcuatus was high (d=0.17) and similar to the genetic distance between C. bellicosus and the allopatric C. sapidus from the western Atlantic (d=0.18), suggesting an ancient (Miocene) divergence of C. bellicosus and C. arcuatus.Communicated by P.W. Sammarco, Chauvin     

Zooplankton responses to hypoxia: behavioral patterns and survival of three species of calanoid copepods

Seasonally recurrent and persistent hypoxic events in semi-enclosed coastal waters are characterized by bottom-water dissolved oxygen (d.o.) concentrations of < 2.0 ml l⁻¹. Shifts in the distribution patterns of zooplankters in association with these events have been documented, but the mechanisms responsible for these shifts have not been investigated. This study assessed interspecific differences in responses to hypoxia by several species of calanoid copepods common off Turkey Point, Florida, USA: Labidocera aestiva (Wheeler) (a summer/fall species), Acartia tonsa (Dana) (a ubiquitous year-round species), and Centropages hamatus (Lilljeborg) (a winter/spring species). Under conditions of moderate to severe hypoxia 24-h survival experiments were conducted for adults and nauplii of these species from August 1994 to October 1995. Experiments on adults used a flow-through system to maintain constant d.o. concentrations. Adults of A. tonsa showed no decline in survival with d.o. as low as 1.0 ml l⁻¹, sharp declines in survival at d.o. = 0.9 to 0.6 ml l⁻¹, and 100% mortality with d.o. = 0.5 ml l⁻¹. Adults of L. aestiva and C. hamatus were more sensitive to oxygen depletion: both species experienced significant decreases in survival for d.o. = 1.0 ml l⁻¹. Nauplii of L. aestiva and A. tonsa showed no significant mortality with d.o. = 1.1 to 1.5 ml␣l⁻¹ and d.o. = 0.24 to 0.5 ml l⁻¹, respectively. In addition, experiments investigating behavioral avoidance of moderate to severe hypoxia were carried out for adults of all three species. None of the three species effectively avoided either severely hypoxic (d.o. < 0.5 ml l⁻¹) or moderately hypoxic (d.o. ≈ 1.0 ml l⁻¹) bottom layers in stratified columns. These results suggest that in␣nearshore areas where development of zones of d.o. < 1.0 ml l⁻¹ may be sudden, widespread, or unpredictable, patterns of reduced copepod abundance in bottom waters may be due primarily to mortality rather than avoidance. Received: 31 August 1996 / Accepted: 24 September 1996     

Obtaining species: sample size considerations

Suppose fish are to be sampled from a stream. A fisheries biologist might ask one of the following three questions: ‘How many fish do I need to catch in order to see all of the species?’, ‘How many fish do I need to catch in order to see all species whose relative frequency is more than 5%?’, or ‘How many fish do I need to catch in order to see a member from each of the species A, B, and C?’. This paper offers a practical solution to such questions by setting a target sample size designed to achieve desired results with known probability. We present three sample size methods, one we call ‘exact’ and the others approximate. Each method is derived under assumed multinomial sampling, and requires (at least approximate) independence of draws and (usually) a large population. The minimum information needed to compute one of the approximate methods is the estimated relative frequency of the rarest species of interest. Total number of species is not needed. Choice of a sample size method depends largely on available computer resources. One approximation (called the ‘Monte Carlo approximation’) gets within ±6 units of exact sample size, but usually requires 20–30 minutes of computer time to compute. The second approximation (called the ‘ratio approximation’) can be computed manually and has relative error under 5% when all species are desired, but can be as much as 50% or more too high when exact sample size is small. Statistically, this problem is an application of the ‘sequential occupancy problem’. Three examples are given which illustrate the calculations so that a reader not interested in technical details can apply our results.