Geology topics

Nadav Nur

Publications and source records attributed to Nadav Nur.

3 recordsLinked to original sources

USGS2018

Rising tides: Assessing habitat vulnerability for an endangered salt marsh-dependent species with sea-level rise

Salt marsh-dependent species are vulnerable to impacts of sea-level rise (SLR). Site-specific differences in ecogeomorphic processes result in different SLR vulnerabilities. SLR impacts to Ridgway’s rail ( Rallus obsoletus ) of Southern California (SC) and San Francisco Bay (SF), U.S.A. could foreshadow SLR effects on other coastal endemic species. Salt marsh vulnerabilities to SLR were forecasted across 14 study sites using the Wetland Accretion Rate Model of Ecosystem Resilience, which accounts for changes in above and belowground marsh processes. Changes in suitable habitat for rail were projected with MaxEnt. Under a high (166 cm/100 yr) SLR scenario, current extent of suitable habitat is projected to increase by 34% across the combined area of 14 sites by 2050, but by 2100, total habitat suitability is projected to decrease by 83%, with six salt marshes losing over 95% of suitable habitat. Under a high SLR scenario, SF’s suitable habitat is predicted to increase by 35% at mid-century, and SC’s current suitable habitat extent will increase by 24%. However, by 2100, SF is forecasted to lose 84% of suitable habitat and SC to lose 80% of its current habitat extent. If accretion rates cannot keep pace with SLR, salt marsh obligate species are in danger of being extirpated from their habitat.

California↗

USGS2011

Avian communities in tidal salt marshes of San Francisco Bay: A review of functional groups by foraging guild and habitat association

The San Francisco Bay estuary is highly urbanized, but it supports the largest remaining extent of tidal salt marshes on the west coast of North America as well as a diverse native bird community. San Francisco Bay tidal marshes are occupied by more than 113 bird species that represent 31 families, including five subspecies from three families that we denote as tidal-marsh obligates. To better identify the niche of bird species in tidal marshes, we present a review of functional groups based on foraging guilds and habitat associations. Foraging guilds describe the method by which species obtain food from tidal marshes, while habitat associations describe broad areas within the marsh that have similar environmental conditions. For example, the ubiquitous song sparrows (Alameda Melospiza melodia pusillula , Suisun M. m. maxillaris , and San Pablo M. m. samuelis ) are surface-feeding generalists that consume prey from vegetation and the ground, and they are found across the entire marsh plain into the upland–marsh transition. In contrast, surface-feeding California black rails ( Laterallus jamaicensis coturniculus ) are cryptic, and generally restricted in their distribution to the mid- and high-marsh plain. Although in the same family, the endangered California clapper rail ( Rallus longirostris obsoletus ) has become highly specialized, foraging primarily on benthic fauna within marsh channels when they are exposed at low tide. Shorebirds such as the black-necked stilt ( Himantopus mexicanus ) typically probe in mud flats to consume macroinvertebrate prey, and are generally restricted to foraging on salt pans within the marsh plain, in ponds, or on mud flats during transitional stages of marsh evolution. The abundance and distribution of birds varies widely with changing water depths and vegetation colonization during different stages of restoration. Thus, tidal-marsh birds represent a rich and diverse community in bay marshes, with niches that may be distinguished by the food resources they consume and the habitats that they occupy along the tidal gradient.

California↗

USGS2002

Management and conservation of San Francisco Bay salt ponds: effects of pond salinity, area, tide, and season on Pacific Flyway waterbirds

Throughout the world, coastal salt ponds provide habitat for large numbers and diversities of water- birds. San Francisco Bay contains the most important coastal salt pond complexes for waterbirds in the United States, supporting more than a million waterbirds through the year. As an initial step in attempting to understand how the anticipated conversion of salt ponds to tidal marsh might affect the Bay's bird populations, the number of birds using salt ponds on high and low tides was counted during the winter months of 1999/00 and 2000/01. Be- havior and habitat use of birds in these ponds were assessed, and the effects of tide cycle, pond salinity, and pond area on bird use were examined. We recorded 75 species ofwaterbirds in surveys of salt ponds in the South Bay from September 1999 to February 2001, totaling over a million bird use days on high tide. Shorebirds and dabbling ducks were the most abundant groups of birds using the salt ponds. Waterbird numbers and diversity were significantly affected by the salinity of ponds in a non-linear fashion with lower numbers and diversity on the highest salinity ponds. With the exception of ducks and Eared Grebe (Podiceps nigricollis), tide height at the Bay significantly affect- ed bird numbers in the salt ponds with ponds at high tides having higher numbers of birds than the same ponds on low tides. Considerable numbers of birds fed in the salt ponds on high and low tides, although this varied greatly by species. Habitat use varied by tide. Management recommendations include maintaining ponds of varying salini- ties and depths. Restoring salt ponds to tidal marsh should proceed with caution to avoid loss of waterbird diversity and numbers in San Francisco Bay.

Waterbirds↗