Coastal Prairie Research Articles

Long-Term Contaminant Exposure Alters Functional Potential and Species Composition of Soil Bacterial Communities in Gulf Coast Prairies.

Environmental pollution is a persistent threat to coastal ecosystems worldwide, adversely affecting soil microbiota. Soil microbial communities perform critical functions in many coastal processes, yet they are increasingly subject to oil and heavy metal pollution. Here, we assessed how small-scale contamination by oil and heavy metal impacts the diversity and functional potential of native soil bacterial communities in the gulf coast prairie dunes of a barrier island in South Texas along the northern Gulf of Mexico. We analyzed the bacterial community structure and their predicted functional profiles according to contaminant history and examined linkages between species diversity and functional potential. Overall, contaminants altered bacterial community compositions without affecting richness, leading to strongly distinct bacterial communities that were accompanied by shifts in functional potential, i.e., changes in predicted metabolic pathways across oiled, metal, and uncontaminated environments. We also observed that exposure to different contaminants can either lead to strengthened or decoupled linkages between species diversity and functional potential. Taken together, these findings indicate that bacterial communities might recover their diversity levels after contaminant exposure, but with consequent shifts in community composition and function. Furthermore, the trajectory of bacterial communities can depend on the nature or type of disturbance.

Using Remotely Sensed Data to Identify Coastal Prairie Remnants in Louisiana

Using Remotely Sensed Data to Identify Coastal Prairie Remnants in Louisiana

Drought and vegetation restoration lead to shifts in soil microbial diversity and co-occurrence networks in California coastal prairie

Abstract Background and aims Both drought and vegetation restoration can have dramatic effects on plant community composition, but how they influence soil microbial community diversity, structure, and co-occurrence networks remain less well known. Methods To better understand the regulatory mechanisms of drought and vegetation restoration on soil microorganisms, we planted 12 native species in precipitation manipulation experimental plots in an invaded coastal grassland in California, USA. We measured soil bacterial and fungal community composition by amplicon sequencing, and quantified plant species richness and coverage in the third experimental year. Results Our results showed that drought significantly altered soil bacterial diversity and composition; however, neither drought nor vegetation restoration had significant effects on fungal diversity and composition. The control plots had the most cooperative interactions (greatest number of correlations) among bacterial and/or fungal species, while drought plots yielded the most complex co-occurrence network with the highest modularity and clustering coefficient. Structural equation modeling revealed that plant species richness, net gains, and soil moisture played dominant roles in shaping bacterial community structure. Drought and bacterial community structure directly affected fungal community structure. Plant dominant species cover, common species cover, and bacterial diversity were the key drivers in regulating the microbial co-occurrence network complex. Conclusion We conclude that soil bacterial and fungal communities differ in their responses to abiotic and biotic environmental changes, which may weaken the interspecies interactions among soil microorganisms.

SOIL CARBON STOCKS NOT LINKED TO ABOVEGROUND LITTER INPUT AND CHEMISTRY OF OLD-GROWTH FOREST AND ADJACENT PRAIRIE

ABSTRACT The long-standing assumption that aboveground plant litter inputs have a substantial influence on soil organic carbon storage (SOC) and dynamics has been challenged by a new paradigm for SOC formation and persistence. We tested the importance of plant litter chemistry on SOC storage, distribution, composition, and age by comparing two highly contrasting ecosystems: an old-growth coast redwood (Sequoia sempervirens) forest, with highly aromatic litter, and an adjacent coastal prairie, with more easily decomposed litter. We hypothesized that if plant litter chemistry was the primary driver, redwood would store more and older SOC that was less microbially processed than prairie. Total soil carbon stocks to 110 cm depth were higher in prairie (35 kg C m−2) than redwood (28 kg C m−2). Radiocarbon values indicated shorter SOC residence times in redwood than prairie throughout the profile. Higher amounts of pyrogenic carbon and a higher degree of microbial processing of SOC appear to be instrumental for soil carbon storage and persistence in prairie, while differences in fine-root carbon inputs likely contribute to younger SOC in redwood. We conclude that at these sites fire residues, root inputs, and soil properties influence soil carbon dynamics to a greater degree than the properties of aboveground litter.

Scales of Diversity Affecting Ecosystem Function across Agricultural and Forest Landscapes in Louisiana

Current land use and extensive modifications of natural ecosystems across the state of Louisiana are generally similar to those across the southeastern USA where rainfall supports forest ecosystems. Both intentional and unintentional consequences of ecosystem modifications from the scales of water and sediment movement across a field edge to state-wide loss of functional grasslands are legacies from previous development across the state. While major investments and large-scale, long-term plans are aspects of some continuing ecological issues across the state, small-scale, volunteer-led restoration of native grassland plant communities in the Louisiana Coastal Prairie illustrates the value associated with the restoration of natural ecosystem function in drastically disturbed environments. As is now becoming increasingly recognized, Louisiana grasslands represent less obvious components of forest, woodland, and wetland landscapes across the state, where they have contributed essential wildlife habitat, and ecosystem functions. These are now largely missing from many landscapes across the state and region. The strategic restoration of grassland functions combining novel native grass pastures and fully functional native grassland plant communities as landscape components could provide both economic and ecosystem benefits. Specific native grassland seed resources are needed for various restoration activities to enhance ecosystem function at a range of scales across the state and region.

Climate change and plant-microbe interactions: Water-availability influences the effective specialization of a fungal pathogen

Through species-specific effects on plants, pathogens play a key role in structuring plant communities. A change in abiotic context, such as those mediated by climate change, may alter plant communities through changes in the specificity of plant-pathogen interactions. To test how water availability influenced the specificity of plant-pathogen interactions, we grew paired congeners of three native and three nonnative coastal prairie plant species with or without a pathogenic soil fungus, Fusarium incarnatum-equiseti species complex 6 b, under low, average, and high water treatments. Across the plant species tested, the Fusarium treatment had stronger negative and species-specific effects on plant biomass at high water availability than low water availability. If generalizable, our results suggest that stronger and more species-specific pathogen effects could drive changes in plant community composition in wetter conditions, but plant-pathogen interactions may be less important for plant community structure in drier conditions.

Patch Burning Improves Nutritional Quality of Two Gulf Coast Grasses—And Winter Burning Is Better than Summer Burning

Gulf cordgrass (Spartina spartinae [Trin.] Merr. ex Hitchc.) and seacoast bluestem (Schizachyrium scoparium [Michx.] Nash var. littorale [Nash] Gould) are dominant native warm season grasses in the Texas Coastal Prairies and Marshes ecoregion. Mature Gulf cordgrass nutritive value is considered poor for grazing animals, while seacoast bluestem nutritive value is considered fair to good in spring and early summer. We compared season of burn effects on crude protein (CP) and neutral detergent fiber (NDF) of these grasses. Our study employed four patches (200–305 ha) burned in a patch-burn grazing system (two winter, two summer 2016). Forage samples were collected before burning and every 3 d for 40 d after burning, then weekly for 50 d. Regardless of season of burning, CP was adequate for maintaining a lactating beef cow 90 d post-burning. Although peak CP in Gulf cordgrass following burning did not differ between seasons, CP increased more quickly following winter burning, when it rose abruptly for ~6.4 d and then increased more slowly to its peak at ~30 d post burn, after which it declined. After summer burning, CP of Gulf cordgrass did not increase significantly, and then declined after reaching its peak at ~29 d post burn. Gulf cordgrass NDF declined more rapidly following summer burning than winter burning but remained low for a longer period after winter burning. In seacoast bluestem, CP increased following winter burning, peaking at ~11 d after burning, but there was little change following summer burning, which did not peak until 31 d post burn. NDF of seacoast bluestem declined similarly in both seasons. This study indicates that prescribed fire during winter is more beneficial for improving the nutritive value of Gulf cordgrass and seacoast bluestem than summer burning.

A FLORISTIC STUDY OF SWANTON PACIFIC RANCH, SANTA CRUZ COUNTY, CALIFORNIA

The Swanton Pacific Ranch (SPR) is located north of the town of Davenport, in Santa Cruz County, California, and is owned by California Polytechnic State University, San Luis Obispo. SPR is approximately 1295 ha and contains areas of salt marsh, coastal prairie, coastal bluff scrub, northern coastal scrub, riparian forest, redwood forest, mixed evergreen forest, and chaparral. The property extends over an elevational gradient from 0 m to 420 m. In this study, we conducted a floristic inventory at SPR and documented 636 taxa. Between 2017 and 2019 we vouchered 547 taxa with 974 specimens. We were unable to locate 63 taxa that had been previously reported, 27 represented from historic collections and 36 represented by personal observations, but lacking vouchers. We relocated, but did not collect, 26 taxa known from previous collections. Overall, we documented 93 families at SPR, with Asteraceae, Poaceae, and Fabaceae having the most species, respectively. California rare taxa, listed by the California Native Plant Society, made up 2.5% of the flora (n = 18). Locally rare taxa made up 10% of the flora (n = 65). Non-native taxa made up 26% of the flora (n = 169). We vouchered one new taxon for Santa Cruz County, Senecio aphanactis Greene, which has a California Rare Plant Rank of 2B.2; documented a new occurrence of Hesperocyparis abramsiana (C.B.Wolf) Bartel var. abramsiana, a Federally Threatened conifer; and collected a form of Sanicula crassicaulis Poepp. Ex DC that we have published as a distinct variety. Overall, this relatively small coastal ranch contained approximately 10% of the flora of California. The 2020 CZU Lightning Complex Fire burned ca. 90% of SPR within a year of this study being completed. This opens the possibility for this study to be used as a baseline for future studies examining post-fire shifts in plant diversity at a landscape scale.

Native and invasive bunchgrasses have different responses to trail disturbance on California coastal prairies

Ecosystems often experience small-scale disturbances through recreational foot and bike traffic. The intermediate disturbance hypothesis predicts that frequent disturbances in grasslands can negatively impact native species and lead to invasion by disturbance-adapted, non-native species. Disturbance studies often examine intentional or unintended larger scale disturbances, but do not commonly focus on common small-scale disturbances such as those caused by trampling along trails. As such, we were interested in how trail disturbance affects the vegetative growth and reproductive output of in situ native (Danthonia californica Bol. and Stipa pulchra Hitchc.) and invasive (Dactylis glomerata L. and Holcus lanatus L.) perennial bunchgrasses commonly found on California coastal prairies. We measured the basal circumference and seed production of plants located on-trail and off-trail on five coastal prairies in Santa Cruz, CA, USA. We hypothesized that native grasses located on-trail would have lower growth and reproductive output and non-native grasses would be unaffected. We found that native and non-native plants had differences in growth and reproductive output on-trail and off-trail. S. pulchra had lower reproductive potential (via culm sterility) with trail disturbance, whereas both native grasses showed evidence of compensatory growth on-trail. Invasive non-native D. glomerata and H. lanatus growth was unaffected by trail disturbance, but H. lanatus had lower reproductive output on-trail. Results suggest that it may be prudent to restore trails with disturbance tolerant species like D. californica and use less tolerant species like S. pulchra further into the central habitat space.

Native annual forbs decline in California coastal prairies over 15 years despite grazing.

Livestock grazing is often used as a land management tool to maximize vegetation diversity in grassland ecosystems worldwide. Prior research has shown that cattle grazing benefits native annual forb species in California's coastal prairies, but drought and increasing aridity may alter this relationship. In 2016 and 2017, we resurveyed the vegetation structure, native annual forb cover, and native annual forb richness in ten grazed and ungrazed prairies that were originally measured in 2000 and 2001 along a 200-km gradient from Monterey to Sonoma counties in California. We found that grazed prairies continued to have significantly lower vegetation height and thatch depth than ungrazed prairies, and that shrub encroachment over the 15-year period was significantly greater in ungrazed prairies. Furthermore, grazed prairies continued to have greater native annual forb richness (4.9 species per site) than ungrazed sites (3.0 species per site), but native annual forb richness declined by 2.8 species per site in grazed prairies and 0.1 species per site in ungrazed prairies between survey periods. We suggest that severe drought and increasing aridity may be driving declines in native annual forb richness in grazed prairies. The species we recorded only in earlier surveys were disproportionately wetland-associated and had higher average specific leaf area than species that remained through the second survey period. Finally, the cover of native annual species increased regardless of whether prairies were grazed, suggesting that the high precipitation in 2017 may have benefitted the native annual forb species that persisted at sites between surveys. Our study shows that weather conditions affect the outcomes of land management strategies.

First documentation of Dichanthelium caerulescens (Poaceae) for the vascular flora of Louisiana, U.S.A.

Dichanthelium caerulescens is documented for the first time in Louisiana, as the result of floristic fieldwork performed in 2019 through 2021. Louisiana records extend the range of D. caerulescens westward by approximately 265 mi (426.5 km) into the Western Gulf Coastal Plain ecoregion. These findings also identify a new habitat, coastal prairie, utilized by D. caerulescens.

The effects of external forcing agents on the biodiversity and species richness associated with the environmental history of Louisiana's wetlands over the late Holocene

This study evaluates plant diversity and species richness levels and reconstructs the environmental history of a site near Little Lake in southeast Louisiana, USA over the past 3200 years. Six successive ecosystems occurred as a result of changing environmental conditions, ranging from the local (anthropogenic activities), regional (delta lobe switching), and to global (sea level rise): interdistributary bay (3.2–2.3 cal kyr BP), hydrophytic freshwater marsh (2.3–1.42 cal kyr BP), mesophyte coastal prairie (1.42–0.92 cal kyr BP), Typha marsh (0.92–0.33 cal kyr BP), intermediate marsh (0.33 cal kyr Bp – ad, 1972 CE), brackish marsh (197 CE2-present). Biodiversity was evaluated for each ecosystem, with maximum diversity occurring during the period of maximum delta-growth as the river dynamics increased landscape heterogeneity by creating diverse habitats, including marsh, swamps, oxbow lakes, and natural levees, while the transgressive phase presents the lowest biodiversity due to increasing salinity. Multivariate analysis is used to identify the primary depositional processes for each stage and infer the proximate forcing agents(s). Early ecosystem shifts were controlled by the stages of the delta cycle, while more recent shifts are associated with anthropogenic activities and the effects of global climate change such as sea-level rise, and more intense tropical cyclones.

Structure and functional composition of macroinvertebrate communities in coastal plain streams across a precipitation gradient

Abstract Climate change is expected to alter rainfall and temperature regimes across the world. The hydrology and riparian zone vegetation of lotic ecosystems are tightly linked to rainfall and a mechanistic understanding of the effects of rainfall on lotic ecosystems is needed to forecast the ecological impacts of climate change. However, it is difficult to isolate rainfall effects from other environmental variables that covary across climates. To address this, we leveraged a unique steep rainfall gradient with few covarying changes in elevation, temperature, and geology to evaluate the effects of rainfall on stream invertebrate communities. We surveyed nine streams in the Texas Gulf Coast Prairie distributed along a 550–1,350 mm/year rainfall gradient. Four sites were classified as drier semi‐arid streams (<750 mm annual rainfall) and five sites were classified as wetter sub‐humid streams (>750 mm annual rainfall). A suite of characteristics including benthic invertebrate community metrics, flow conditions, and water quality variables were assessed monthly for 14 months at each site to relate precipitation regime to stream structure and function. Precipitation regime was observed to be a master explanatory variable. As annual rainfall increased, the flow environment became more stable within seasons and predictable across seasons, influencing spatial structure and temporal variability of invertebrate community composition. Wetter streams were dominated by slower growing taxa without adaptions for desiccation resistance and strong dispersal. Wetter sites displayed seasonal variation in community composition and species richness, whereas temporal variation in communities in drier streams was controlled by stochastic variation in flow conditions. These observations show that differences in local annual rainfall correlated with major changes to community structure and functional composition. We hypothesise that this association is related to the connection of rainfall to hydrological stability, particularly the frequency of low flow disturbances, and the subsequent effects on riparian vegetation and temporally available niches to stream invertebrates. Our work adds to evidence that alterations in precipitation patterns associated with climate change have sweeping impacts on lotic fauna.

Changes in precipitation patterns can destabilize plant species coexistence via changes in plant-soil feedback.

Climate change can alter species coexistence through changes in biotic interactions. By describing reciprocal interactions between plants and soil microbes, plant-soil feedback (PSF) has emerged as a powerful framework for predicting plant species coexistence and community dynamics, but little is known about how PSF will respond to changing climate conditions. Hence, the context dependency of PSF has recently gained attention. Water availability is a major driver of all biotic interactions, and it is expected that precipitation patterns will change with ongoing climate change. We tested how soil water content affects PSF by conducting a full factorial pairwise PSF experiment using eight plant species common to southeastern United States coastal prairies under three watering treatments. We found coexistence-stabilizing negative PSF at drier-than-average conditions shifted to coexistence-destabilizing positive PSF under wetter-than-average conditions. A simulation model parameterized with the experimental results supports the prediction that more positive PSF accelerates the erosion of diversity within communities while decreasing the predictability in plant community composition. Our results underline the importance of considering environmental context dependency of PSF in light of a rapidly changing climate.

Mechanisms for retention of low molecular weight organic carbon varies with soil depth at a coastal prairie ecosystem

Though primary sources of carbon (C) to soil are plant inputs (e.g., rhizodeposits), the role of microorganisms as mediators of soil organic carbon (SOC) retention is increasingly recognized. Yet, insufficient knowledge of sub-soil processes complicates attempts to describe microbial-driven C cycling at depth as most studies of microbial-mineral-C interactions focus on surface horizons. We leveraged a well-studied paleo-marine terrace (90 ka) located near Santa Cruz, CA, to characterize the short-term (days to weeks) and intermediate-term (months to years) fate of two low molecular weight organic carbon. compounds at three depths in the soil profile (∼25 cm, A horizon; ∼75 cm A/B transition; and ∼125 cm, B horizon). We employed isotopically-labeled glucose (GLU) and oxalic acid (OXA) to represent two common classes of rhizodeposits: carbohydrates and organic acids. Using a combination of laboratory (9 d) and field (490 d) incubations, we traced the fate of GLU-C and OXA-C through dissolved-, metal-associated-, and microbially-respired CO2 and bulk SOC pools. Our results suggest new SOC retention (i.e., defined as 13C label identified in solid or aqueous fractions) over intermediate time frames (490 d) is correlated with patterns in short-term (9 d) cycling dynamics, which in turn is related to the theoretical efficiency by which microorganisms process each substrate. For all horizons (A, A/B, and B) GLU-C was converted to CO2 more quickly than OXA-C with modeled decomposition rates ∼2–4 times faster for GLU depending on microbial density (higher in A than B horizon). The faster decomposition rates of GLU-C increased fractional recovery (0.399 ± 0.026 to 0.504 ± 0.030 for GLU-C) compared to OXA-C (0.035 ± 0.003 to 0.127 ± 0.010) among all horizons in our field experiment (490 d). Though the overall proportion of GLU-C recovered in solid fractions did not vary significantly with horizon, based on 13C recovered in aqueous fractions the apparent mechanism for retention did. After the 9-d laboratory incubation, fractional recovery for GLU-C among C pools associated with microbial biomass was almost 20× higher than OXA-C (0.192 versus 0.010, respectively across all horizons). More than a year later, 43–46% of GLU-C retained in the field incubation was extractable with a neutral salt (representing a pool of soil C residing within or available to microbial biomass) among A and A/B horizons, while only 6% of retained GLU-C was similarly extractable in the B horizon. Thus, it appears among depths with higher microbial density (A, A/B horizons), anabolic recycling is the most likely process contributing to the persistence of glucose C, whereas abiotic sinks contributed more to intermediate-term stability for GLU-C in the B horizon. By contrast, most OXA-C was lost, presumably as CO2, over the short-term from the A and A/B horizons (fractional recovery: 0.136 ± 0.011 and 0.091 ± 0.002, respectively). However, though substantially lower than GLU-C recovered at the conclusion of our field experiment, the fraction of oxalic acid C retained in the B horizon over both short- (0.72 ± 0.037) and intermediate-time (0.127 ± 0.010) frames was several-fold higher than for overlying horizons. The specific process(es) (e.g., more efficient microbial utilization, metal-organic complexation, direct adsorption to the mineral matrix, etc.) contributing to higher retention for OXA-C at depth are discussed but remain unresolved.

Northern Bobwhite Response to Control of Red Imported Fire Ants in the Gulf Coast Prairie of Texas

The population decline of northern bobwhite (Colinus virginianus; hereafter, bobwhite) on the Texas Gulf Coast Prairie, USA is largely attributed to habitat loss. However, red imported fire ants (Solenopsis invicta) occur throughout the region and are considered a possible contributing factor to the bobwhite decline. The objectives of our study were to determine the influence of red imported fire ants on bobwhites by comparing bobwhite nest success, survival, and density between sites treated with fire ant bait (treatment) and reference (control) sites. Our study was conducted on 3 private ranches in Goliad and Refugio counties, Texas. Each ranch contained 2 paired experimental units that consisted of a treatment and control site (500 ha each). The treatment sites received an aerial application of fire ant bait (Extinguish® Plus) during April 2018, whereas the control sites were not treated. We estimated mound density by counting fire ant mounds using distance sampling. We used radio-telemetry to monitor bobwhite nest success and survival, and we estimated bobwhite densities using distance sampling via helicopter surveys. Fire ant mound density decreased through time on both treatment and control sites. However, fire ant mound density was lower on treatment sites than control sites, indicating the insecticide was effective at decreasing fire ant mound density. Bobwhite survival, nest success, and density did not statistically differ between control and treated sites either pre-treatment (2017) or post-treatment (2018), but survival and nest success metrics were numerically higher in treated units. Bobwhite survival remained relatively stable in the treatment units 4 weeks after application but decreased in the control units. Following treatment, apparent nest success in the treated units increased by 37.4% while nest success in the control units decreased by 35.2%. Bobwhite populations were low in this ecoregion, which influenced our ability to trap and monitor many bobwhites or monitor many nests. In addition, it may be possible that repeated, annual treatments for fire ants are necessary for a benefit to accrue and be observed in bobwhites. Our results indicate that there may be potential benefits to bobwhites from fire ant reduction that deserve further research attention.

Estimates of breeding season location for 4 mesic prairie bird species wintering along the Gulf Coast

During the last 2 centuries, widespread declines have been observed in migratory species, and these declines have largely been linked to anthropogenic causes. Migrants move across multiple spatiotemporal scales with wide-ranging movements that can cross multiple jurisdictions. Consequently, conservation and management require the incorporation of these wide-ranging movements. However, for many nongame species, basic information on migration and wintering ecology is poorly known. Yellow Rails (Coturnicops noveboracensis), LeConte's Sparrows (Ammospiza leconteii), Nelson's Sparrows (A. nelsoni), and Sedge Wrens (Cistothorus stellaris) represent a diverse avian assemblage that breeds in prairie potholes, boreal forest, and coastal areas of northern and eastern Canada and winters in coastal prairies in the southern United States. We used a stable deuterium isotope (δ2Hf) analysis to assign breeding season locations for individuals captured wintering in the southeastern US. We obtained deuterium values from secondary feathers of birds spending the nonbreeding season from Oklahoma and Texas east to Florida. We found substantial differences in the δ2Hf values of Yellow Rails and Nelson's Sparrows, with birds wintering in Oklahoma and the western Gulf of Mexico having δ2Hf values that were probabilistically assigned to the western half of their breeding range, while birds wintering in Florida were probabilistically assigned to the eastern portion of their breeding range. LeConte's Sparrow breeding season assignments for birds wintering in Texas and Oklahoma overlapped. Sedge Wrens did not exhibit spatial variation in isotope values.

An updated checklist to the biodiversity data of ladybeetles (Coleoptera: Coccinellidae) of the Azores Archipelago (Portugal).

BackgroundA recently-published review from 2021 presents a comprehensive checklist of ladybeetles of Portugal, including the Azores and Madeira Archipelagos. Until then, the available information was very scattered and based on a single revision dating back to 1986, a few international catalogues and databases, individual records and studies on communities of agroecosystems. However, no information was available on faunal composition across the Azorean islands and their habitats, using standardised inventories. Here, we present data about the biodiversity of ladybeetles and their distribution and abundance in five Islands of the Azores (Faial, Graciosa, Pico, São Jorge and São Miguel). Surveys included herbaceous and arboreal habitats from native to anthropogenic-managed habitats: ruderal road vegetation, vegetable garden, mixed forest of endemic and non-native host plants, coastal prairies, coastal mixed vegetation, cornfields and urban areas. We aimed to contribute to the ongoing effort to document the terrestrial biodiversity of Portugal, including the Archipelago of the Azores, within the research project AZORESBIOPORTAL–PORBIOTA (ACORES-01-0145-FEDER-000072).New informationIn this study, a total of 1,487 specimens of Coccinellidae belonging to 19 species are reported for several habitats. The listed species are from one single sub-familiy (Coccinellinae) and six tribes; Chilocorini (one species), Coccidulini (three species), Coccinellini (six species), Noviini (one species), Scymnini (seven species), Stethorini (one species). The number of species collected per island differed; Faial (10 species), Graciosa (four species), Pico (seven species), São Jorge (seven species) and São Miguel (12 species). For six species, new island records are given. Currently, the number of species known to occur in the Azores are 32, including two doubtful records. The majority of species are Scymnini, being Scymnus (Scymnus) interruptus (Goeze, 1777) and Scymnus (Scymnus) nubilus Mulsant, 1850, the most abundant species (relative abundance 71.1%). This database will be the baseline of a long-term monitoring project allowing assessment of the impact of ongoing global changes in the distribution and abundance of ladybeetles.

Yucca carrii (Asparagaceae), a New Species from the Northern Gulf Coast Prairie of Texas

Yucca carrii, a new species from the northern Gulf Coastal Prairie of Texas is described. Morphology indicates that Yucca carrii belongs to Section Chaenocarpa (the dry-fruited yuccas). A lack of observed fruit production to date and reduced pollen viability indicates that this species may be of hybrid origin. The sole pollinator, the yucca moth, has not been documented within the species' range; it may be extirpated. Although known from few populations, the wide-ranging distribution of this species along the north Texas coast, ecological niche specificity and morphological distinctiveness indicates this taxon may have a long history in the area and persists by way of vegetative reproduction. It may be vulnerable to extinction and conservation measures are warranted. DNA analyses are needed to determine the origin and relationship of Y. carrii within Yucca L. Examination of the type of Y. tenuistyla Trel. revealed Y. tenuistyla is a nomen confusum that was described from a mixed collection of three yucca species, none of which is Y. carrii.

Spatial and temporal refugia for an insect population declining due to climate change

AbstractInsect declines have been reported worldwide, although the particular causes of the declines may be complex and are poorly understood. Meadow spittlebugs were one of the most abundant insects in the coastal prairie along the California coast 40 yr ago but have largely disappeared. Evidence links this decline to changing climatic conditions, which have reduced survival of eggs and neonates. We identified several refugia where meadow spittlebug populations have persisted amidst unfavorable conditions. Protection from desiccating winds was the common attribute of these refugia. Following a wet year, adult meadow spittlebugs were able to disperse from one refuge that we studied to recolonize coastal prairie habitats, although populations declined over the next two drier years. Because of their previous high abundance, loss of meadow spittlebugs is likely to affect the functioning of this widespread habitat, including energy transfer, their host plants, and their predators. In addition, meadow spittlebugs are unusual in having been the subject of extensive physiological and long‐term ecological data, so they can serve as a bellwether species, indicating the effects of climate change.