El Niño episodes coincide with California moray Gymnothorax mordax settlement around Santa Catalina Island,California

The hypothesis that El Niño events influence the settlement patterns of the California moray Gymnothorax mordax is tested. The pelagic larval duration (PLD) of larval G. mordax is unknown, but studies on leptocephalus of related species suggest that larvae are long‐lived, up to 2 years. Gymnothorax mordax, an elusive predatory species and the only muraenid off the coast of California, is considered abundant in the waters around Catalina Island. Thirty‐three individuals were collected from Two Harbors, Catalina Island, and otoliths were taken to provide estimates of their age. Settlement year for each individual was backcalculated using estimated age from otolith measurements. These ages were then cross referenced with the Oceanic Niño Index (ONI) developed by the National Oceanographic and Atmospheric Administration (NOAA) to correlate estimated age of settlement with known El Niño years. Of the 33 individuals collected, 30 settled at Catalina Island during El Niño years. The oldest individual in the data‐set was 22 years old, placing G. mordax as one of the longer‐lived predatory fishes in the system. The present study represents the first account of wild G. mordax ages and suggests that El Niño events have an important role in driving the settlement of recruits towards the northern edge of their range.     

Detection of mitochondrial DNA from domestic cattle in bison on Santa Catalina Island

In 1924, 14 American bison (Bison bison) were introduced to Santa Catalina Island, California and sporadically supplemented thereafter with additional animals. To reduce the herd and its impact on native vegetation, over 2000 animals have been exported during the past four decades. Today, the herd is estimated to contain around 250 individuals. Genetic analysis was performed on 98 animals removed from the island in 2004. Forty-four samples (45%) had domestic cattle mitochondrial DNA (mtDNA), 12 (12%) had previously reported bison haplotypes and 42 (43%) had a new haplotype differing by one base pair from a previously reported bison haplotype. A complement of five restriction enzymes was found to be useful in identifying bison with domestic cattle mtDNA.     

Demographic and genetic structures of two partially isolated communities of Santa Catarina Island,southern Brazil

The objectives of this study were to analyze the population structure and genetic variability of two communities, Costa da Lagoa (CLG) and S?o Jo?o do Rio Vermelho (SJRV), located on Santa Catarina Island in southern Brazil. The two populations descend from Azores Archipelago immigrants (Portuguese), with a minor contribution of sub-Saharan Africans and Amerindians. To estimate the relative contribution of the different ethnic groups to the current gene pool of the two communities, values of admixture were obtained using the weighted least-squares method based on allelic frequencies of the loci ABO, RHD-RHCE, GPA-GPB (MNSs), HBB, HP, TF, CP, AK, and ACP1. The origins of the studied populations can be quantified as follows: for CLG, sub-Saharan Africans (A) = 17.3%, Iberian Europeans (P) = 75.0%, and Southern Amerindians (I) = 7.7%; for SJRV, A = 48.8%, P = 44.5%, and I = 6.7%. Because haplotype frequencies of the GPA-GPB loci in SJRV were unusual, possibly as a consequence of random genetic drift, the values of admixture were recalculated after exclusion of GPA-GPB, as follows: A = 28.0%; P = 53.3%, and I = 18.7%. The total diversity (HT) was estimated as 42.29%, of which 99.6% can be attributed to the intrapopulational variability (HS). The interpopulational genetic variation (or standard distance, DST) corresponds to 0.19%, while the gene differentiation coefficient is 0.28%, indicative of low genetic difference. These results led to the conclusion that random genetic drift may have had an important effect on the Costa da Lagoa community, while presently gene flow might be the predominant evolutionary factor potentially capable of changing allele frequencies in SJRV.     

Reproductive behaviour of a temperate serranid fish, Paralabrax clathratus(Girard), from Santa Catalina Island, California, U.S.A.

The reproductive behaviour of the kelp bass Paralabrax clathratus was studied on Santa Catalina Island, California, U.S.A. from April 2000 to September 2002. Adults formed aggregations of three to > 200 individuals, and spawning occurred within subgroups of three to 23 individuals that contained a single female. The gonado‐somatic index ( I _G) of collected ripe males (mean = 5·8%, range = 0·5–13·1%) indicated a large investment in sperm production that is common in group‐spawning fishes characterized by intense sperm competition. Spawning occurred 32 min before sunset to 120 min after sunset, and both males and females were capable of spawning multiple times during a single evening. Behavioural observations of adults and estimates of spawning periodicity from the collection of females with hydrated oocytes suggested that spawning occurred continuously throughout the summer months and showed no significant relationship with the lunar cycle. In general, the spawning behaviour of kelp bass was similar to other functionally gonochoric, group‐spawning serranids. The dynamics of P. clathratus spawning aggregations, however, were inconsistent with that of tropical reef fish spawning aggregations, including the transient spawning aggregations of some tropical serranids. Aggregation spawning appeared to be an important component of the annual reproduction of this species.     

Ear mite infection is associated with altered microbial communities in genetically depauperate Santa Catalina Island foxes (Urocyon littoralis catalinae)

The host‐associated microbiome is increasingly recognized as a critical player in health and immunity. Recent studies have shown that disruption of commensal microbial communities can contribute to disease pathogenesis and severity. Santa Catalina Island foxes (Urocyon littoralis catalinae) present a compelling system in which to examine microbial dynamics in wildlife due to their depauperate genomic structure and extremely high prevalence of ceruminous gland tumors. Although the precise cause is yet unknown, infection with ear mites (Otodectes cynotis) has been linked to chronic inflammation, which is associated with abnormal cell growth and tumor development. Given the paucity of genomic variation in these foxes, other dimensions of molecular diversity, such as commensal microbes, may be critical to host response and disease pathology. We characterized the host‐associated microbiome across six body sites of Santa Catalina Island foxes, and performed differential abundance testing between healthy and mite‐infected ear canals. We found that mite infection was significantly associated with reduced microbial diversity and evenness, with the opportunistic pathogen Staphylococcus pseudintermedius dominating the ear canal community. These results suggest that secondary bacterial infection may contribute to the sustained inflammation associated with tumor development. As the emergence of antibiotic resistant strains remains a concern of the medical, veterinary, and conservation communities, uncovering high relative abundance of S. pseudintermedius provides critical insight into the pathogenesis of this complex system. Through use of culture‐independent sequencing techniques, this study contributes to the broader effort of applying a more inclusive understanding of molecular diversity to questions within wildlife disease ecology.     

Passive Recovery of Vegetation after Herbivore Eradication on Santa Cruz Island,California

Understanding how insular ecosystems recover or are restructured after the eradication of an invasive species is crucial in evaluating conservation success and prioritizing island conservation efforts. Globally, herbivores have been removed from 762 islands, most with limited active restoration actions following eradication. Few studies have documented the effects of invasive herbivore removal after multiple decades of passive recovery. Here we evaluate recovery of vegetation on Santa Cruz Island, California, after the removal of feral sheep (Ovis aries) in 1984. We repeat a study conducted in 1980, and examine vegetation changes 28 years after the eradication. Before eradication, grazed areas were characterized by reduced plant cover, high exposure of bare ground, and erosion. After 28 years of passive recovery, transect data showed a 23% increase in woody overstory, whereas analysis of photographs from landscapes photographed pre‐ and post‐eradication showed a 26% increase in woody vegetation. Whole island vegetation maps similarly showed a transition from grass/bare ground (74.3% of cover) to woody plants (77.2% of cover), indicating the transition away from predominantly exotic annual grassland toward a community similar to the overstory of coastal scrubland but with an understory dominated by non‐native annual grasses. We estimate that replacement of grasses/bare ground by native woody vegetation has led to 70 and 17% increases in the stored carbon and nitrogen pools on the island, respectively. Our results demonstrate that these island ecosystems can experience significant recovery of native floral communities without intensive post‐eradication restoration, and results of recovery may take decades to be realized.     

Summer dietary compositions of sika deer on Yakushima Island,southern Japan

Summer food habits of Sika deer (Cervus nippon yakushimae) on Yakushima Island, southern Japan, were studied focusing in particular onPseudosasa owatarii, a dwarf bamboo native to the island. Fecal analyses showed that the food habit of the Sika deer on Yakushima island was plastic: the dietary composition was dominated by graminoids (ca. 90%), particularlyP. owatarii (50%–60%) in the bamboo grassland of theP. owatarii zone above the timber line, whereas leaves and non-leafy parts of woody plants were important in the crytomeria forest and evergreen broad-leaved forest below the timber line. The maximum culm age ofP. owatarii was 8.5 yr, but the majority of leaves (97.8%) were younger than 2.5 yr. Since the weight contribution of the leaves is great (27.7%) and the turnover rate is high, theP. owatarii grassland affords a good foraging place for the Sika deer on Yakushima Island.     

Distribution and habitat associations of the California moray (<Emphasis Type="Italic">Gymnothorax mordax</Emphasis>) within Two Harbors,Santa Catalina Island,California

While kelp forests are some of the best-surveyed ecosystems in California, information on cryptic inhabitants and their role within the community are lacking. Kelp itself provides overall structure to the habitat; however the rocky reef to which the kelp attaches is known to provide additional structure for cryptic species. Gymnothorax mordax, the California moray, is an elusive predatory species that is considered abundant in the waters around Catalina Island. However, no life history data exists for this species. We examined habitat composition, relative abundance, size pattern distributions, and biomass of G. mordax within Two Harbors, Catalina Island. Habitats were sampled using a combination of baited trap collection and transect surveys using SCUBA. A total of 462 G. mordax were captured, primarily in shallow (< 10 m) waters. Individuals of G. mordax were associated with mostly boulder and cobble substrates. Measurements of relative abundance and density indicate that G. mordax is more prevalent than reported in previous studies. We also discovered that the 6 trapping sites from which all morays were collected, differed in size structuring and density while the relatively high biomass did not change across sites. In general, southern facing sites exhibited higher densities of morays, while northern facing sites showed more size structuring. We show how the structural complexity of the rocky reef habitat in an already diverse kelp forest ecosystem, can support a high biomass of a cryptic elongate predatory fish.     

Environmental factors influencing spatial patterns of shrub diversity in chaparral,Santa Ynez Mountains,California

We examined patterns of shrub species diversity relative to landscape‐scale variability in environmental factors within two watersheds on the coastal flank of the Santa Ynez Mountains, California. Shrub species richness and dominance was sampled at a hierarchy of spatial units using a high‐powered telescope from remote vantage points. Explanatory variables included field estimates of total canopy cover and percentage rock cover, and modeled distributions of slope, elevation, photosynthetically active radiation, topographic moisture index, and local topographic variability. Correlation, multiple regression, and regression tree analyses showed consistent relationships between field‐based measurements of species richness and dominance, and topographically‐mediated environmental variables. In general, higher richness and lower dominance occurred where environmental conditions indicated greater levels of resource limitation with respect to soil moisture and substrate availability. Maximum richness in shrub species occurred on high elevation sites with low topographic moisture index, rocky substrate, and steep slopes. Maximum dominance occurred at low elevation sites with low topographic variability, high potential solar insolation, and high total shrub canopy cover. The observed patterns are evaluated with respect to studies on species‐environment relations, resource use, and regeneration of shrubs in chaparral and coastal sage scrub. The results are discussed in the context of existing species‐diversity hypotheses that hinge on reduced competitive dominance and increased resource heterogeneity under conditions of resource limitation.     

Response to ammonium and nitrate by a mycorrhizal annual invasive grass and native shrub in southern California

The goal of this study was to determine the interaction of mycorrhizae and two N sources, ammonium (NH(4)(+)) and nitrate (NO(3)(-)), on the growth of a coastal sage scrub (CSS) species, Artemisia californica, and an exotic annual grass, Bromus madritensis ssp. rubens. Anthropogenic nitrogen deposition may be influencing the decline of CSS and replacement by exotic grasses, but the extent to which mycorrhizae are involved in shrubland decline is unknown. NO(3)(-) is the dominant form of deposition in southern California, although the native, uneutrophied soils have a greater concentration of NH(4)(+). Seeds of each species were germinated in pots of sterile soil, inoculated with native soil containing mycorrhizal spores and infective root fragments, and fertilized with 50 μg/g of either NO(3)(-) or NH(4)(+). NH(4)(+) enhanced the growth of both mycorrhizal species, while NO(3)(-) did not. Control plants of B. madritensis under low N had a significant response to mycorrhizae, but A. californica did not. Nitrate increased the growth of nonmycorrhizal A. californica as much as the mycorrhizal NH(4)(+)-treated plants. There is no evidence in this study to suggest that the decline of A. californica or increase in B. madritensis is due to a mycorrhizal response to NO(3)(-). Other life history traits of the two species must be used to explain the invasive behavior of the annual grass. Mycorrhizae may be more important in controlling plant growth in native uneutrophied soils dominated by NH(4)(+) rather than NO(3)(-).     

Seasonal cycle of planktonic communities at Inhaca Island, southern Mozambique

Monthly plankton sampling was carried out at three stationson the west coast of Inhaca Island, southern Mozambique, fromAugust 1994 to August 1995. Sampling included water mass physicalparameters, nutrients, chlorophyll and zooplankton with netsof 125 and 330 µm pore aperture. Nutrient concentrationhas shown maxima during the summer months, where rain providesthe maximum outflow of rivers discharging into Maputo Bay. Followingthe nutrient peak, chlorophyll a has shown maxima around themonth of April, with another minor peak in September, when temperaturebegins to increase. Zooplankton densities followed closely thephytoplankton peaks, especially small herbivorous taxa and larvalstages, such as gastropod and bivalve larvae.     

Aerial arthropod communities of native and invaded forests, Robinson Crusoe Island, Chile

Invasive species significantly contribute to biological change and threaten biodiversity, with a growing body of evidence that plant invasions affect higher trophic levels. We explored the relative importance of plant invasion and forest structure on aerial arthropod abundance, diversity, and composition on Robinson Crusoe Island, Chile. We used flight intercept traps to sample aerial arthropods within distinct canopy strata of native and invaded forests over 3-mo periods in 2006 and 2007. Arthropod abundance and diversity were higher in native than invaded forest, and arthropod communities were distinct between forest types. In both forest types, arthropod abundance was highest in the lower canopy, and canopy strata exhibited some differences in arthropod community composition. Several morphospecies were distinctly associated with each forest type. The strong differences in aerial arthropod communities associated with the invasion of native forest by non-native plants may affect other trophic levels, such as insectivorous birds. Steps to stop invasive plant spread and to restore native forest composition and structure are needed to safeguard the integrity of native communities, from plants to higher-level consumers.     

Meiofauna and macrofauna communities in a mangrove from the Island of Santa Catarina, South Brazil

The composition and abundance of the meiofauna and macrofauna were studied in a survey carried out within 6 locations in a mangrove at the Island of Santa Catarina, South Brazil. Nine meiofaunal taxa were registered with densities ranging between 77 and 1589 inds.10 cm^?2. The nematodes, composed by 94 putative species (86 genera), largely dominated the meiofauna. The most abundant genera were Haliplectus (Haliplectidae), Anoplostoma (Anoplostomatidae) and Terschillingia (Linhomoidae). Contrary to the meiofauna, the macrofauna showed a low number of taxa (only 17 recorded) and abundance (up 7250 inds.m^?2). The macrofauna was mainly composed by deposit feeders, and numerically dominated by oligochaetes and capitellid polychaetes. For both components, differences in the composition and abundance along the sampling sites were significant but not primarily related to the typical variations along estuaries, such as salinity. The results of the stepwise multiple regression analyses showed that the detritus biomass (ash-free dry weight) was the most important predictor of faunal densities and diversity. The clear relationship between detritus and fauna, together with the contrasting community structure of the two component of the benthos suggest that the meiofauna showed a high efficiency in exploiting the micro-habitat created by the presence of the detritus. Yet the macrofauna, potentially the main consumer of the debris, is negatively affected by their low palatability and poor nutritive value.     

Effect of domestic wastes on the benthic marine communities of southern California

A total of 3,785 million 1 of domestic wastes is emptied into the marine waters of southern California each day. Over 85% of these wastes receive primary treatment before discharge into offshore waters. Most of these wastes are discharged at four localities: El Segundo (Los Angeles City), White's Point (Los Angeles County), Newport Beach (Orange County), and Pt. Loma (San Diego City). While some studies were conducted at these localities prior to 1970, all of these sanitation districts have been monitoring the benthic environment since 1971–1973. Some predictions on the effect of domestic discharges on benthic life were made based on the amount of primary effluent discharged per day. If the amount discharged into open oceanic waters is less than 18 million 1/day, then a biological enhancement is noted with an increase in biomass, number of species and specimens, and diversity. If the amount of discharge exceeds 40–180 millions 1/day, then the biomass, number of specimens, and area affected is increased, but the number of species, diversity, and richness is decreased. A faunal index was devised by the personnel at Southern California Coastal Water Research Project to represent these generalities graphically.     

Pathology and Epidemiology of Ceruminous Gland Tumors among Endangered Santa Catalina Island Foxes (Urocyon littoralis catalinae) in the Channel Islands,USA

In this study, we examined the prevalence, pathology, and epidemiology of tumors in free-ranging island foxes occurring on three islands in the California Channel Islands, USA. We found a remarkably high prevalence of ceruminous gland tumors in endangered foxes (Urocyon littoralis catalinae) occurring on Santa Catalina Island (SCA)—48.9% of the dead foxes examined from 2001–2008 had tumors in their ears, and tumors were found in 52.2% of randomly-selected mature (≥ 4 years) foxes captured in 2007–2008, representing one of the highest prevalences of tumors ever documented in a wildlife population. In contrast, no tumors were detected in foxes from San Nicolas Island or San Clemente Island, although ear mites (Otodectes cynotis), a predisposing factor for ceruminous gland tumors in dogs and cats, were highly prevalent on all three islands. On SCA, otitis externa secondary to ear mite infection was highly correlated with ceruminous gland hyperplasia (CGH), and tumors were significantly associated with the severity of CGH, ceruminous gland dysplasia, and age group (older foxes). We propose a conceptual model for the formation of ceruminous gland tumors in foxes on SCA that is based on persistent, ubiquitous infection with ear mites, and an innate, over exuberant inflammatory and hyperplastic response of SCA foxes to these mites. Foxes on SCA are now opportunistically treated with acaricides in an attempt to reduce mite infections and the morbidity and mortality associated with this highly prevalent tumor.     

Maxillary canine/third premolar transposition in a prehistoric population from Santa Cruz Island, California.

Canine/premolar transposition is rare in both historic and prehistoric Homo sapiens with a known occurrence of less than 0.10%. This report describes a prehistoric population sample from one site (SCrI-3) on Santa Cruz Island, California in which the rate of C/P3 transposition is greater than eight percent, based on nine of 106 adult crania which exhibit the anomaly either uni- or bilaterally. As a means of investigating the etiology of this anomaly, the location of the canine root in adult crania was studied. Root location should indicate tooth bud origin, a factor likely to be under genetic control. In crania with normally erupted canines, the superior portion of the root averages 4.43 mm from alare, while this distance is 8.96 mm for anomalous roots. This difference suggests that during ontogeny the tooth buds for the canine and premolar arose in the wrong (or reversed) places, causing the teeth to erupt anomalously. It is suggested that inbreeding in a small island community resulted in a short-lived appearance of this anomaly at a high frequency.     

Patterns of use and damage by exotic deer on native plant communities in northwestern Patagonia

Ungulate overabundance can strongly alter composition and structure of forest communities through selective damage independently of the herbivory history of the recipient system. In the early 1900s, red and fallow deer (Cervus elaphus and Dama dama, respectively) were introduced to northwestern Patagonia. We studied patterns of relative habitat use, damage, and species selection by introduced deer populations in three major plant communities that have the longest history of invasion in the region. We also evaluated community structure and composition characteristics as possible explanatory factors for the observed patterns of browsing, fraying, and bark-stripping. At the species level, exotic deer browsed more than expected on two evergreen species (Austrocedrus chilensis and Schinus patagonicus) and two spiny species (Colletia hystrix and Dasyphyllum diacanthoides), while one dominant shrubland tree (Lomatia hirsuta) was selected for fraying and bark-stripping. Browsing was the more widespread damage in all plant communities, while fraying and bark-stripping occurred at low incidence. Furthermore, species identity was found as the main driver of deer damage over plant community type. Finally, variation in damage and in habitat use was explained by community structure and composition characteristics. Bark-stripping and fraying are best predicted by community composition, whereas browsing and habitat use are best predicted by structural properties including understory cover, cover of fallen logs, and tree density. The patterns of damage and the association with community structure characteristics reported here provide insight for developing management strategies.     

Habitat quality and endoparasitism in the Pacific sanddab Citharichthys sordidus from Santa Monica Bay, southern California

Prevalence, mean abundance and mean intensity of the most common endohelminths infecting Pacific sanddab Citharichthys sordidus were compared among six trawl stations in the Santa Monica Bay. These trawl stations varied in their distance from the 8 km effluent of the Hyperion treatment plant which is situated adjacent to Santa Monica Bay. Juvenile stages of Anisakis sp., Corynosoma sp., Lacistorhynchus dollfusi and Tetraphyllidean plerocercoids were found infecting Pacific sanddabs. Significantly higher prevalence and mean intensity of L . dollfusi and Anisakis sp. were seen at the non-outfall stations compared to outfall stations either immediately surrounding or in the vicinity of the outfall. These differences appeared to be related to changes in invertebrate population densities in response to the presence of contaminants. Canonical analysis of discriminance using parasite abundance data discriminated non-outfall from outfall stations. The cestode L . dollfusi explained most of the variability in discriminant scores generated from the analysis and appears to warrant further investigation as a potential bioindicator of pollution exposure in its fish host.     

Predicting the distribution of shrub species in southern California from climate and terrain-derived variables

Abstract. Generalized additive, generalized linear, and classification tree models were developed to predict the distribution of 20 species of chaparral and coastal sage shrubs within the southwest ecoregion of California. Mapped explanatory variables included bioclimatic attributes related to primary environmental regimes: averages of annual precipitation, minimum temperature of the coldest month, maximum temperature of the warmest month, and topographically-distributed potential solar insolation of the wettest quarter (winter) and of the growing season (spring). Also tested for significance were slope angle (related to soil depth) and the geographic coordinates of each observation. Models were parameterized and evaluated based on species presence/absence data from 906 plots surveyed on National Forest lands. Although all variables were significant in at least one of the species’ models, those models based only on the bioclimatic variables predicted species presence with 3–26% error. While error would undoubtedly be greater if the models were evaluated using independent data, results indicate that these models are useful for predictive mapping – for interpolating species distribution data within the ecoregion. All three methods produced models with similar accuracy for a given species; GAMs were useful for exploring the shape of the response functions, GLMs allowed those response functions to be parameterized and their significance tested, and classification trees, while some-times difficult to interpret, yielded the lowest prediction errors (lower by 3–5%).