Defining the coast and sentinel ecosystems for coastal observations of global change

The detection, attribution and prediction of global and large scale regional change are goals for the Global Observing Systems of the United Nations. Coastal areas are particularly sensitive to global change, but there is a variety of limitations to universal coverage of observations. The coastal module of the Global Terrestrial Observing System (C-GTOS) considers sentinel ecosystems to address these goals for the terrestrial, wetland and freshwater ecosystems of the coast. Sentinel ecosystems for observing systems are a limited number of well understood systems that have substantial datasets and are observed in a sustained fashion, forming an early warning and core system for broader regional and global change. A necessary step in the development of C-GTOS is the examination of current definitions of coastal areas by anticipated users and information providers, and identification of potential coastal networks and sites. We applied the sentinel system framework to the selection of C-GTOS observation sites from several international programs using various global delineations of coastal areas. Delineations were based on the most common definitions of the coast adopted by potential C-GTOS users and information providers, and included mapped areas of various distance from the coastline, coastal areas of low elevation, and a seaward boundary matching the Economic Exclusive Zone (EEZ). Decreases in the number of sites within each international program occurred with each definition marking area closer to the coastline. The Ramsar Convention on Wetlands demonstrates the greatest percentage of coastal sites by any definition. The process of choosing specific sentinel sites for C-GTOS continues from this initial screening, and is the next step towards the development of an in situ site network supporting the observation of global and large scale change. An erratum to this article is available at .     

Temporal variation and landcover influence survival in adult female mottled ducks

Adult survival is a key driver of waterfowl population growth and is subject to temporal and spatial variation. Mottled ducks (Anas fulvigula) are native to the Gulf Coast and peninsular Florida, USA, and have suffered population declines over the past decade, especially in Texas and Louisiana, USA. Although the cause of this decline is not well understood, previous research concluded variation in survival contributed to nearly a third of variation in the species' population growth rate. We used global positioning system-groupe spécial mobile (GPS-GSM) transmitters to study temporal and spatial variation in survival of adult female western Gulf Coast mottled ducks in southwestern Louisiana, 2017–2020. We evaluated weekly survival models parameterized with combinations of hunted and non-hunted periods, biological seasons, and landcover types that were used by mottled ducks. There were 3 competitive survival models, and all contained 4 parameters that parsed the annual cycle into the non-hunted period, first part of the general waterfowl season, and second part of the waterfowl season, and included the proportion of GPS locations in agricultural lands. Weekly survival was 0.979 during the first part of the general waterfowl hunting season, and 0.996 during the second part of the general waterfowl season. Daily survival rate increased with an increasing proportion of locations logged in agricultural lands. Annual survival rates were similar to other waterfowl that are not experiencing population declines, which suggests survival is not limiting population growth of mottled ducks along the western Gulf Coast. Managers should ensure the availability of refuge areas where hunting is prohibited during the first part of the general waterfowl season, when mottled ducks are at an increased risk of mortality, in addition to the targeted conservation of agricultural lands that provide cover and forage.     

Presence of Echinorhinus cookei off central Pacific Mexico

On 19 May 1999, the capture of a neonate male of the prickly shark Echinorhinus cookei (377 mm L _T) off Michoacán Coast (18°40'N: 103°47'W) was recorded. The prickly shark was found at a depth of 132 m; it was collected over muddy bottom using a trawl net. In Mexico, representatives of this species are scarce o. the Pacific Coast; this new record extends the known southern range 261 km from 21°01'N to 18°40'N for the continental coast. The organism was deposited in the ichthyological reference collection of the Centro de Investigación en Alimentación y Desarrollo, A.C, Unidad Mazatlán (catalogue number, CIAD 01–03 Mazatlán). Morphometric and meristic characteristics of the specimen are given.     

Fruit Traits in Baboon Diet: A Comparison with Plant Species Characteristics in West Africa

Primate fruit choice among plant species has been attributed to different morphological plant and fruit characteristics. Despite a high abundance of animal-dispersed plant species in the savanna–forest mosaic of West Africa, few data are available on the interplay between morphological fruit traits and primate fruit consumers in this ecosystem. We tested whether olive baboons (Papio anubis) at Comoé National Park, north-eastern Ivory Coast, prefer fruit species with particular characteristics relative to the availability of these traits among the woody plant species at the study site. Specifically we were interested in the suites of traits that best predict fruit choice and seed handling by baboons. The baboons ate fruit/seeds from 74 identified plant species, representing 25 percent of the regional pool of woody plant species. They preferred trees to shrubs and lianas as fruit sources. Otherwise, baboons seemed to consume whatever fruit type, color, and size of fruit and seeds available, though they especially included larger fruit into their diet. Against expectations from the African bird–monkey fruit syndrome of brightly colored drupes and berries, baboons ate mostly species having large, dull-colored fruit. Fruit type and color best described whether baboons included a species into their diet, whereas fruit type and seed size best predicted whether baboons predated upon the seeds of their food plant species. As most plant species at the study site had medium-sized to large fruits and seeds, large frugivores like baboons might be particularly important for plant fitness and plant community dynamics in West African savanna–forest ecosystems.     

The emergence of Cochlodinium along the California Coast (USA)

A sudden and nearly synchronous emergence of the red tide forming dinoflagellate Cochlodinium along more than 800 km of California coastline was initially observed in late summer 2004. Thereafter high cell concentrations have been detected on an annual basis. Here, we present quantitative and semi-quantitative data indicating that Cochlodinium was uncommon in the phytoplankton community in California prior to 2004 and is now persisting as a more regular component and one that seasonally can cause red tides. The quantitative portion of this study was primarily conducted in Monterey Bay, where cell densities reached at least 6 × 10⁴ cells L⁻¹ during the initial outbreak. A semi-quantitative comparison of California coastal counties by the California Department of Health Services (CDHS) was also made: of the 15 counties surveyed (most with multiple sites per county), cells were detected only from Los Angeles County in the south to San Mateo County in the central region (seven counties), but not in the northern part of the state (six counties). Two counties in the central region of the state, San Luis Obispo and Santa Cruz, displayed intense and frequent periods of elevated Cochlodinium cell abundances. Although not observed in the state-wide CDHS survey, we occasionally found cells in San Diego County with densities up to 2.7 × 10⁴ cells L⁻¹. Though these colonial dinoflagellates have been recognized in California for over 80 years, with several “blooms” recorded prior to 2004, the species’ geographic range and abundance in recent years suggest significant shifts in the nearshore phytoplankton community of this region of the eastern Pacific.     

An inverted latitudinal gradient of plant diversity in shallow depressions on Ivorian inselbergs

The vegetation of shallow depressions on Ivorian granite inselbergs was studied along a gradient from the savanna zone in the north to the rainforest zone in the south of the country. Short-term inundation and prolonged drought are typical features of this habitat. In total, 64 taxa belonging to 25 families were recorded, with the Poaceae, Cyperaceae and Fabaceae accounting for the greatest proportion of species. Annuals represent the predominant life form and comprise nearly two thirds of all species recorded. DCA ordination of the sample plots illustrates that diversity decreases from north to south, and is accompanied by a gradual transition in the ambient vegetation from savanna to rainforest. This decrease is in marked contrast with diversity of surrounding vegetation types. In the drier northern area, it appears as if the less favourable environmental conditions prevent a state of community equilibrium being attained in the shallow depressions. This enables weak competitors to co-exist along with more vigorous species, which, in the south of the country, form species-poor stands. Furthermore, the fact that inselbergs in the rainforest zone are more isolated enhances the probability of extinction of less competitive associates.     

Dendrochronological analysis of Sequoia sempervirens in an interior old-growth forest

Dendrochronological studies of large and old Sequoia sempervirens are limited by access and complex crossdating, but core sampling at regular height intervals along the main trunks of five standing trees allowed for reconstruction of growth, height, and age while providing within-tree replication for crossdating. We developed a crossdated ring-width chronology (1453–2015) for redwoods growing in an easternmost old-growth forest in the Napa Range of California, determined aboveground tree attributes, investigated the inter-annual climate-growth relationships since the late 19th century, and documented long-term growth trends. Age, height, f-DBH (functional diameter at breast height), and aboveground biomass of these co-dominant trees ranged from 241 to 783 years, 45.7 to 61.5 m, 117.0 to 226.9 cm, and 9.34 to 33.62 Mg, respectively. Bootstrapped correlation and response function analysis showed radial growth positively related to May through August Palmer Drought Severity Index (PDSI) and negatively related to maximum June temperature (r ≥ │0.47│, P < 0.0001), explaining 33.3% of ring-width variation. Bootstrapped correlations over a moving 40-year window indicated strengthening relationships with PDSI and minimum temperature. The long-term growth trend, reflected by the size-detrended metric of residual wood volume increment (RWVI), varied over time and showed an average one-year decrease of 13.3% for 20th and 21st century droughts. A fire detected in August 1931 corresponded with a one-year decrease in RWVI of 43.1% followed by >100% increase within five years. Growth dynamics for redwoods in this interior forest provide a point of comparison for redwoods previously studied in old-growth forests along the latitudinal gradient, highlighting range-wide trends and site-specific differences in responses to climate and fire.     

Cyanobacteria and Cyanobacterial Lichens from Inselbergs of the Ivory Coast,Africa

This study focuses on the saxicolous lichens and cyanobacteria of the open, exposed rock surface of inselbergs. Twenty-three species of cyanobacteria and 17 cyanobacterial lichen species (“cyanolichens”) from several inselbergs and other rocky outcrops of three major climatic regions, savanna, transition zone and rain forest, are reported from the Ivory Coast. Inselbergs are isolated and frequently mountains consisting of Precambrian granites or gneisses that abruptly rise from the surrounding plains. Cyanobacteria were found to be the dominating organisms on all rock surfaces. The lichens found mainly belong to the family Peltulaceae and a few were present from the family Lichinaceae. Nine species of the cyanolichens and most of the cyanobacteria are new for the Ivory Coast. A gradient in total species number (cyanolichens and cyanobacteria) occurs from the savanna to the rain forest, with a decrease in species number towards the rain forest. Saxicolous cyanobacterial lichens reached a higher species number in the savanna type ecosystem (11) than on inselbergs in the rain forest (7). The cyanolichens and cyanobacteria found are characteristic for larger, light-exposed rock surfaces and species like P. congregate, P. lingulata, P. tortuosa and P. umbilicata preferentially occur on the granite or sandstone of inselbergs.