Assessing and Mitigating the Effects of Windblown Soil on Rare and Common Vegetation

Acting under the auspices of the US Endangered Species Act, we quantified wind erosion and its effects on rare and common plant species on a semi-arid military installation in Hawaii. Our goal was to develop management strategies, based on local data, to aid the conservation of rare and common indigenous plants and their habitats. We collected windblown soil coming off of roads and other disturbed soils to assess likely impacts to plants occurring at certain heights and distances from disturbed surfaces. We then subjected plants in a glasshouse to windblown dust treatments, designed from our field data to simulate erosion events, and evaluated the effect of these treatments on photosynthesis and survival. We also designed several field experiments to examine the in-situ effects of windblown soil and soil substrate on germination, growth rate, and survival of indigenous and nonindigenous plants. We conclude from these experiments that most direct effects of windblown soil to plants can be effectively mitigated by locating roads and training areas at least 40 m from sensitive plant habitats and through vegetation management to maintain at least 11% aerial cover on disturbed surfaces. Effects of soil type on germination, growth, and survival was species-specific, emphasizing the importance of species trials prior to, or during, rehabilitation efforts.     

Development and application of a video-mosaic survey technology to document the status of coral reef communities

The recent decline in the condition of coral reef communities worldwide has fueled the need to develop innovative assessment tools to document coral abundance and distribution rapidly and effectively. While most monitoring programs rely primarily on data collected in situ by trained divers, digital photographs and video are used increasingly to extract ecological indicators, provide a permanent visual record of reef condition, and reduce the time that divers spend underwater. In this study, we describe the development and application of a video-based reef survey methodology based on an algorithm for image registration and the estimation of image motion and camera trajectory. This technology was used to construct two-dimensional, spatially accurate, high-resolution mosaics of the reef benthos at a scale of up to 400 m². The mosaics were analyzed to estimate the size and percent cover of reef organisms and these ecological indicators of reef condition were compared to similar measurements collected by divers to evaluate the potential of the mosaics as monitoring tools. The ecological indicators collected by trained divers compared favorably with those measured directly from the video mosaics. Five out of the eight categories chosen (hard corals, octocorals, Palythoa, algal turf, and sand) showed no significant differences in percent cover based on survey method. Moreover, no significant differences based on survey method were found in the size of coral colonies. Lastly, the capability to extract the same reef location from mosaics collected at different times proved to be an important tool for documenting change in coral abundance as the removal of even small colonies (<10 cm in diameter) was easily documented. The two-dimensional video mosaics constructed in this study can provide repeatable, accurate measurements on the reef-plot scale that can complement measurements on the colony-scale made by divers and surveys conducted at regional scales using remote sensing tools.     

THE LEGALIZATION OF GROUNDWATER STORAGE1

ABSTRACT: California's courts have recently recognized the existence of underground aquifer storage rights that permit public agencies to (1) store imported waters in aquifers; (2) prevent others from expropriating that water; and (3) recapture the stored water when it is needed. The article describes the two appellate decisions that represent the common-law development of aquifer storage rights. Each decision related to separate aquifers that were subject to separate types of groundwater management programs. One decision involved an aquifer under the southeastern San Francisco Bay area that was managed under statutory authority and is entitled, Niles Sand and Gravel Co. v. Alameda County Water District 37 C.A.3d 924 (1974); cert. denied 419 US 869. The other decision involved an aquifer under Southern California's San Fernando Valley that was managed under judicial authority and is entitled, City of Los Angeles v. City of San Fernando 14 Cal.3d 199 (1975). The two decisions provide separate, but complimentary, public interest rationales for aquifer storage rights: (1) to protect water supplies necessary for the overlying community; and (2) to increase water supply efficiencies by using natural underground reservoirs wherever practicable. The Article reviews the relationship of aquifer storage rights to conventional groundwater rights and indicates aspects of the storage right that may need additional development.     

Chemical defenses, nutritional quality, and structural components in three sponge species: Ircinia felix, I. campana, and Aplysina fulva

Allocating chemical defenses to regions or tissues most at risk for predatory attack may provide protection while simultaneously minimizing associated metabolic costs. Chemical defense allocation patterns were investigated in the aspiculate sponges Ircinia felix, I. campana, and Aplysina fulva collected between July 2005 and April 2006 from J Reef off the coast of Georgia, U.S.A. It was predicted that chemical defenses would be (1) higher in the outermost 2 mm layer of the sponge; (2) positively correlated with tissue nutritional quality; and (3) correlated with structural components such as spongin fibers. Whereas defensive chemicals were concentrated in the outer 2 mm of A. fulva, the Ircinia species had higher concentrations in deeper tissue layers. Furthermore, no significant positive or negative correlation between chemical defenses and nutritional quality or levels of structural components was observed in these sponges. Overall, these results do not support the prediction that predation pressure by fish and large mobile invertebrates significantly impacts chemical defense allocation in these sponges.     

Ultraviolet radiation effects on the behavior and recruitment of larvae from the reef coral Porites astreoides

We tested the rarely considered hypothesis that the ultraviolet portion (UVR, 280–400 nm) of the light spectrum affects patterns of recruitment in reef-building corals. The premise for this hypothesis rests in the fact that biologically relevant intensities of UVR penetrate to considerable depths (>24 m) in the clear waters surrounding many coral reefs, and that reef organisms allocate substantial resources to prevent and repair UVR damage. The ability of larvae spawned by the brown morph of the Caribbean coral, Porites astreoides, to detect and avoid UVR was assessed in petri dishes where one-half of the dish was shielded from UVR and the other exposed. Observations made every 30 min between 10:30 and 13:30 h showed significantly higher densities of larvae swimming in regions shielded from UVR. To determine how this behavior affects settlement patterns, larvae collected from P. astreoides adults at 18 m depth were released into chambers deployed at 17 m depth where they were given a choice of three different light regions in which to settle: PAR (PAR=400–700 nm), PAR+UVAR (UVAR=320–400 nm), and PAR+UVAR+UVBR (UVBR=280–320 nm). At the end of the experiment, greater numbers of P. astreoides larvae had settled in the region of the tube where UVR was reduced than would be expected if dispersion were random. To our knowledge, this is the first demonstration in any reef-building coral species that planula larvae can detect UVR and that it affects their choice of a settlement site. These results indicate that the capacity to detect and avoid habitats with biologically damaging levels of UVR may be one factor contributing to the successful recruitment of coral larvae.     

The effect of light and heterotrophy on carotenoid concentrations in the Caribbean anemone<Emphasis Type="Italic"> Aiptasia pallida</Emphasis> (Verrill)

One of the consequences of ultraviolet radiation exposure in anthozoans possessing photosynthetic endosymbionts (i.e., zooxanthellae) is production of reactive oxygen species that can damage cellular components, especially lipids and photosynthetic membranes. It is well known that carotenoids are potent antioxidants that can mitigate oxygen radical damage, but the origin of these compounds in zooxanthellate anthozoans is obscured because they can potentially originate from endosymbionts, heterotrophic feeding by the host, or a combination thereof. We used Aiptasia pallida, a common Caribbean anemone, to investigate the effects of exogenous food sources, ultraviolet-A radiation (UVA, 320–400 nm), and photosynthetically active radiation (PAR, 400–700 nm) on carotenoid levels in zooxanthellate anthozoans. Anemones were exposed to one of three simulated light treatments in the laboratory for 38 days: PAR (60% below ambient)/UVA (similar to ambient), PAR/low UVA (42% below ambient), and low PAR (98.4% below ambient)/no UVA. In addition, anemones were either fed a carotenoid-rich diet of Artemia salina nauplii, or starved. Carotenoids identified in A. pallida included peridinin, diadinoxanthin, diatoxanthin and -carotene. While a diet of Ar. salina nauplii had no effect on the carotenoid composition of A. pallida, a two-way analysis of variance revealed that anemones exposed to ambient UVA levels had significantly greater diatoxanthin concentrations relative to the total xanthophyll pool [diato:(diato+diadino)] after 10 days of exposure. This difference among treatments was not present at 20 days, but reappeared as an effect due to starvation rather than UVA at days 30 and 38. These results suggest that carotenoids in A. pallida are not influenced by exogenous feeding and that photoprotective xanthophyll cycling is sensitive to stresses such as UVA and starvation.Communicated by P.W. Sammarco, Chauvin