The objective of this work is to estimate the effect of floods on the riparian vegetation communities of the Gila Box, Arizona, based on historical maps, satellite images, and GPS-referenced airborne video. The condition and extent of selected riparian vegetation communities in 1973, 1982, and 1991 are documented. Changes in riparian vegetation communities for the time period from 1973 to 1982 and from 1982 to 1991 are analyzed to assess the potential effect of floods that occurred in 1978 and 1983, respectively. The results indicate that the floods in 1978 and 1983 may have had an impact on the mesquite riparian community. The effect of floods on riparian vegetation is most apparent in the downstream portion of the Gila River. The information collected and presented in this work can be used to formulate effective management plans to the Gila Box area.

Gila chub (Gila intermedia) were at lower densities in areas of Sabino Creek with green sunfish (Lepomis cyanellus) than areas without sunfish. No young-of-year (YOY) chub were observed in pools where densities of sunfish were reduced by about 90% or in control pools, but YOY chub were abundant in upstream areas without sunfish. The microhabitat selected by YOY chub was nearly identical to that selected by sunfish (7.5 cm, TL). In predation experiments, sunfish (7.5 cm, TL) consumed YOY chub (2.5 cm, TL). The absence of YOY chub in areas with sunfish may, in part, be due to predation by small sunfish. In winter, chub use of microhabitat did not differ in areas with and without sunfish. In summer, chub used faster currents, areas farther from cover and shallower depths in areas with than without sunfish. In summer, niche shifts by chub may be a response to avoid negative interactions with sunfish.

Les produits cosmétiques sont des substances utilisées pour entretenir ou modifier l'aspect des parties superficielles du corps humain (telles que la peau, les ongles ou les cheveux). Dans de nombreux pays d’Afrique et d’Asie et dans certaines communautés africaines immigrantes, plusieurs femmes et parfois des hommes utilisent des produits contenant des agents actifs tels que le mercure, l’hydroquinone et le propionate de clobétasol pour éclaircir leur peau. Ces principaux agents sont toxiques et leur présence dans les cosmétiques est règlementée, voire interdite, dans plusieurs pays. Dans notre étude, nous avons déterminé les concentrations de ces ingrédients dans plusieurs produits utilisés en Afrique de l’Ouest et au Canada. Nous avons également exploré l’effet de ces produits sur le microbiome cutané. Nos résultats révèlent que 68 à 84% des crèmes et 7.5 à 65% des savons dépassent les normes lorsqu’on considère l’interdiction de mercure, d’hydroquinone et de propionate de clobétasol et les concentrations déclarées sur les étiquettes ne sont pas souvent fiables. Selon la diversité de Shannon, il semble y avoir plus d’équitabilité, et donc moins de dominance dans le groupe des femmes utilisant les crèmes éclaircissantes que dans le groupe des femmes qui ne les utilisent pas. Par ailleurs, nous n’avons pas trouvé de différences significatives au niveau du microbiome cutané du groupe avec crèmes et sans crèmes au niveau du phylum et du genre. Cependant, d’autres méthodes plus approfondies avec plus d’échantillonnage pourraient révéler à des échelles plus fines (espèces, souches, etc.) l’effet de ces produits sur le microbiome cutané. / Cosmetics are substances used to maintain or change the appearance of external parts of the human body (such as skin, nails or hair). In many countries of Africa and Asia and in some immigrant African communities, many women and sometimes men use products containing active agents such as mercury, hydroquinone and clobetasol propionate to lighten their skin. These main active agents are toxic and their presence in cosmetics is regulated or even banned in several countries. In our study, we determined the concentrations of these ingredients in many products used in West Africa and Canada. In addition, we also explored the effect of these products on the skin microbiome. Our results reveal that 68 to 84% of cream and 7.5 to 65% of soaps exceed the standards when considering mercury, hydroquinone and clobetasol propionate ban in lightening products and concentrations of the three compounds declared on labels of soaps and creams usually did not correspond to concentrations actually measured. According to Shannon diversity index, there seems to be more evenness, less dominance in group of African women with creams than in those without cream. Moreover, we have not found significant differences in the skin microbiome of the group with creams and the one without creams at the phylum and genus level. However, additional detailed studies with more sampling methods could reveal at finer scales (species, strains, etc.) the effect of these products on the human skin microbiome.

<p>Poslednjih godina u balkanskom regionu pa i u Srbiji, zabeleņeno je ńirenje i invazivne korovske vrste Asclepias syriaca. Pretpostavlja se da je u Srbiju dospela iz susedne MaĎarske gde se dugi niz godina gajila kao medonosna biljka. Zahvaljujući alelopatskim osobinama i jakoj kompetitivnosti, ova vrsta ne dozvoljava regeneraciju starih peńčanih polja Najčeńće se javlja u zapuńtenim voćnjacima i vinogradima, na peskovitim terenima pored puteva i ņelezničkih pruga, nasipima, formirajući pri tom čiste sastojine asocijacije ili se javlja sa joń nekoliko korovskih vrsta ali uz apsolutnu dominaciju A. syriaca. Konstatovano je njeno ńirenje sa parloga na obradive povrńine na kojima obrazuje &bdquo;oaze&ldquo;, naročito u usevima pńenice, ječma, suncokreta, soje, u uljanoj repici, voćnjacima i vinogradima. Imajući u vidu sve negativne aspekte nekontrolisanog ńirenja A. syriaca na ruderalnim i poljoprivrednim povrńinama, ciljevi rada bili su praćenje ńirenja i izučavanje njenih biolońkih i ekolońkih karakteristika kao i utvrĎivanje mogućih načina za njeno suzbijanje. Populacija svilenice na teritoriji Vojvodine ima tendenciju ńirenja i ustaljivanja posebno uz puteve i vodene tokove. UtvrĎena je na skoro svim tipovima zemljińta u Vojvodini. Uspeva na zemljińtima od slabo do jako karbonatnih, kao i od slabo do jako humusnih. Podnosi zemljińta čiji je sadrņaj pristupačnih oblika fosfora i kalijuma ispod donje granice optimalne obezbeĎenosti zemljińta, ali i na zemljińtima gde je sadrņaj vrlo visok do ńtetan. Analizom biolońkog spektra sastojina ass. Asclepiadetum syriacae L&aacute;nikov&aacute; in Chytr&yacute; 2009, utvrĎeno je da su one hemikriptofitsko-terofitskog karaktera sa dominacijom hemikriptofita. Godińnja produkcija semena A. syriaca po m2 je od 1.336,53 do 10.109,61, a sa povećanjem gustine biljaka po jedinici povrńine smanjuje se produkcija plodova. Udeo semena svilenice u ispitivanoj zemljińnoj banci semena je vrlo nizak pa A. syriaca ne formira permanentnu banku semena. Dormantnost semena prekida se njegovim izlaganjem niņim temperaturama tokom nekoliko meseci a vlaga igra značajnu ulogu u povećanju klijavosti semena.<br />Alelopatska svojstva svilenice potvrĎena su ispitivanjem uticaja vodenog ekstrakta iz korena na klijavost semena kukuruza, soje i suncokreta u koncentracijama 0,05-0,1g suvemase korena po 1ml destilovane vode. UtvrĎena je i značajna osetljivost gajenog i divljeg sirka na primenjene ekstrakte. Od ekstrakata korena svilenice pripremljenih sa različitim rastvaračima, najveći inhibitorni uticaj na klijavost semena soje imao je butanolni, a na klijanje semena gajenog sirka etil-acetatni i butanolni ekstrakt. Isto je i sa divljim sirkom i ńtirom, dok na klijavost semena kukuruza i soje ni jedan primenjeni ekstrakt nije imao negativan uticaj u značajnijoj meri. Ogledi u poljskim uslovima pokazali su uticaj alelohemikalija iz korena A. syriaca na redukciju prinosa kukurza i sirka. Vodeni ekstrakt korena u koncentraciji primene 0,04g/ml umanjio je prinos kukuruza za 10-15%, krmnog sirka za 12,5% a sirka metlańa za 23%. Ispitivanja mogućnosti hemijskog suzbijanja A.syriaca u poljskim uslovima pokazali su najveću efikasnost herbicida na bazi glifosata, 2,4-D i tembotriona. kao i nakon trogodińnje primene bentazona, bentazona + dikambe, a najmanja efikasnost ustanovnjena je prilikom primene dikambe. Terbutilazin i klomazon u većim preporučenim količinama primene efikasno suzbijaju svilenicu iz semena ako se herbicidi primene pre nicanja, dok imazamoks i oksasulfuron efikasno suzbijajuu tek iznikle biljke svilenice kada se u preporučenim dozama tretiraju biljke u fazi 2-4 lista.</p> / <p>In previous years in the Balkan region, including Serbia, spread of invasive weed species Asclepias syriaca L. was recorded. It supposedly arrived to Serbia from neighbouring Hungary, where it was grown as honey plant. Due to allelopathic properties and strong concurrence, this species does not allow regeneration of old sand fields. It is most common in neglected orchards and vineyards, sandy terrains along roads and railways, embankments, where form pure A. syriaca association, or several additional weed species occur, but with absolute dominance of this weed. From uncultivated areas on which it forms &quot;oasis&quot; its spread was noted especially in wheat, barley, sunflower, soybean, rapeseed crops, in orchards and vineyards. Considering all negative aspects of uncontrolled spread of A. syriaca on ruderal and agricultural areas, the aims of the paper were monitoring of its spread and the study of biological and ecological properties, as well as the establishment of possible ways of its control. On the territory of Vojvodina, common milkweed population has a tendency of spread and colonization, particularly near roads and water flows. It is established on almost all soil types in Vojvodina. It grows on poor to very calcareous soils, as well as on poor to very humic ones. Common milkweed withstands soil with the content of available forms of phosphorous and potassium below the optimum , but also the soils with high to damaging content of these elements. The analysis of the biological spectrum of stands of ass. Asclepiadetum syriacae, L&aacute;nikov&aacute; in Chytr&yacute; 2009, established that it is hemicryptophyte and therophytein, with a domination of hemicryptophytic character.<br />Annual seed production of A. syriaca seed per m2 is from 1.336,53 to 10.109,61, and with the increase in plant density per unit area, production of fruits is reduced. The share of milkweed seed in soil seed bank is very low, and therefore A. syriaca does not form permanent seed bank. Seed dormancy is stopped by its exposure to lower temperatures for several months, and moisture has an important role in the<br />increase in seed germination. Allelopathic properties of common milkweed were confirmed by examination of root water extract effects on maize , soybean and sunflower seed germination at concentrations of 0.05-0.1g of dry root weight per 1ml of distilled water. Significant susceptibility of cultivated sorghum and Johnson grass to the applied extract was recorded. From common milkweed root extracts prepared by various solvents, the highest inhibiting effect to soybean seed germination had butanol extract, and to germination of seed of cultivated sorghum, ethyl acetate and butanol extract. It was the same with wild sorghum and redroot pigweed while none of the applied extracts had significantly negative effect on maize and soybean germination. In field trials, allelochemicals from A. syriaca root reduced maize and millet yield. Root water extracts at the applied concentration of 0.04g/ml reduced maize yield by 10-15%, of fodder sorghum by 12.5% and broomcorn by 23%. In studies regarding chemical control of A.syriaca in field conditions,the highest efficiency was recorded for herbicides based on glyphosate, 2.4-D and tembotrione, as well as for bentazone and bentazone + dicamba after tree-years long application.Dicamba was recorded as the least efficient. Terbuthylayine and clomazone herbicides in pre-emergence application at higher label rates efficiently control common milkweed from seed, while imazamox and oxasulfuron applied at lable rates efficiently control young plants of common milkweed at the phase of 2-4 leaves.</p>

The northern Swallow-tailed Kite, Elanoides forficatus forficatus, a Neotropical migrant raptor of conservation concern, has failed to recover its former abundance and breeding range following widespread deforestation of breeding habitat and human persecution beginning in the late 19 th Century. The Louisiana-Mississippi subpopulation studied here appears to be limited by intraguild predation involving other species of raptors, especially Great Horned Owls (Bubo virginianus). Predation was documented using a multiple-methods approach that minimized sources of bias. Intraguild predation impacted the subpopulation in multiple ways: Raptors, particularly Great Horned Owls, killed kites of all ages, but especially adult females attending nests, possibly causing breeding-aged female limitation. During monitoring of 290 nests, recently fledged young, and radio-tagged birds (90 fledglings, 13 adults), intraguild predation was the leading cause of mortality, accounting for 50.5-56.8%. Considering mortality attributable to predators on or near nests, the Great Horned Owl was responsible for 50.5-98.1%. Raptor predation was also the leading cause (44.8%) of nest failure (N = 87 failed nests), the remainder attributable to weather and other factors. Intraguild predation was the key-factors (greatest impact on mortality of nest contents), explaining most variation in annual productivity, although weather and unknown causes were nearly as important. Productivity also declined at a rate of 0.057 young per year (1995-2005, 305 nests), and the annual frequency of nest predation contributed substantially to this decline (r = -0.728). Considering radio-tagged fledglings, 12.2% were depredated by raptors (at least 54.5% by owls) prior to first migration. Predation of adult kites attending nests during the 60-day exposure period for this species contributed between 7.87-9.62% to annual adult mortality. Raptor predation was the probable explanation for 81.8% of 22 instances of nesting neighborhood disappearance. The present study identifies the Great Horned Owl as a keystone predator of kites and many other birds Intraguild predation alone is not sufficient to explain the slowness of the kite's recovery. Additional factors implicated include (1) delayed age of first reproduction, perhaps as late as five years of age; (2) social dominance by adults slowing recruitment by pre-breeders failing to obtain a mate or territory; and (3) conspecific attraction potentially inhibiting re-colonization of formerly inhabited geographic areas / acase@tulane.edu

Aedes albopictus is an Asian vector of dengue that has expanded its range over the past decade to include the Americas. As a potential dengue vector in the Western hemisphere, it is important to identify factors that affect this immigrant species and its interactions with the indigenous Ae. aegypti The effect of nutrients and Ascogregarina taiwanensis infections on the bionomics and vector potential of a New Orleans strain of Aedes albopictus were evaluated. Larvae were infected with oocysts and reared under optimal and deficient nutrient conditions using leaf litter as a detritus source. Mortality, development time, wing length and reproductive potential were measured for infected and uninfected groups. Parasitism and low nutrients caused a 35% increase in the rate of larval mortality and doubled the development time, of females. Parasitized adults were 5% smaller and produced 23% fewer eggs. While small body size is correlated with a lowered reproductive capacity, ascogregarine infections caused an additional decrease in fecundity Large, ascogregarine-infected females fed on blood infected with Dirofilaria immitis, had a higher (70%) filaria yield and a lower (22%) post blood meal mortality than single infected females. In large females it is possible that coinfection enhanced the immune response allowing fewer filaria to develop with less host mortality. In small females the lower vector potential may have resulted from low food reserves that limited filarial development, while further reductions in coinfected females may have been caused by ascogregarine damage to tubules Aedes aegypti cross infected with A. taiwanensis showed larval mortality, reduced size and extended development time. Responses varied according to the geographic origin of host and parasite strains, but indicated that the geographic expansion of Ae. albopictus may be aided by ascogregarine infections of the non natural host, Ae. aegypti The combined effects of nutrient levels and parasitism therefore regulate the population density of tire pile Ae. albopictus so the carrying capacity of the habitat is not exceeded. Thee factors also influence the vector capacity of this species for D. immitis. Finally, ascogregarines may play a role in the expansion of Ae. albopictus into habitats occupied by Ae. aegypti / acase@tulane.edu

Technologically advanced countries use more than 10,000 chemicals routinely and approximately 1,500 new chemicals are introduced annually (Connell and Miller 1984). While many of these chemicals are harmless, some have catastrophic effects on aquatic ecosystems and show the most severe effects on higher trophic level consumers, including wading birds through bioaccumulation and biomagnification (Ohlendorf et al. 1979, Spalding et al. 1994). The present study is the first to address three primary questions: (1) Can non-sacrificial sampling of wading birds reflect food chain contamination reliably? (2) Are nestling growth rates or other reproductive indices of the birds affected by food chain contamination? (3) Are reproductive indices related to tissue concentrations of contaminants in these birds? Tissues of White Ibis (WI) and Little Blue Herons (LBH) were sampled from a colony of wading birds near Devil's Swamp, an area known to be polluted with organochlorines and heavy metals, and from four other colonies as controls. Eggs, blood, guano, and food samples were analyzed for hexachlorobenzene, hexachlorobutadiene, lead, and cadmium contamination. Eggshells and feathers were also tested for metal content. LBH chicks were measured twice weekly to ascertain growth rates The data indicate for the first time that food chain contamination by heavy metals can be readily assessed from guano samples collected from chicks of both WI and LBH, and demonstrate differences in metal contamination between polluted and control colonies. This was not true for organochlorine contaminants, which were distributed independently of the metals in the environment. These data are also original in establishing a relationship between the presence of cadmium in feathers and reduced growth rates in LBH, and in demonstrating that lead-exposed chicks had increased nestling mortality. The findings of the present study expand our understanding of wading birds as indicators of environmental contamination in several ways: (1) non-sacrificial sampling can reflect food chain contamination by heavy metals; (2) nestling survival and growth rates are affected by exposure to heavy metals in the food chain; and (3) wading birds bioaccumulate metals and their tissues can thus serve as reliable bioindicators of contamination / acase@tulane.edu

This dissertation investigated larval release and larval behavior of the Caribbean spiny lobster Panulirus argus and the spotted spiny lobster P. guttatus. These species were examined under laboratory conditions to determine the phase relationship between larval release and natural environmental cycles. P. argus displayed a nocturnal tidal rhythm, while P. guttatus displayed a circadian rhythm in larval release. P. argus releases larvae near the time of nocturnal high slack water, while P. guttatus released larvae near the time of sunrise. The role of 'pumping pheromones' in controlling larval release behaviors was tested by measuring the pumping response of ovigerous P. argus to (1) hatch water, (2) homogenized-embryo water, (3) embryo-conditioned water, and (4) water containing homogenized-egg cases. Lobsters with late-stage embryos displayed increased pleopod pumping with increased concentration of hatch water. Water individually conditioned with homogenized late-stage embryos, intact late-stage embryos, and homogenized egg-cases induced pumping activity in females with late-stage embryos, indicating the presence of a chemical cue. I quantified pumping responses upon exposure to synthetic peptides to determine if they mimicked pheromones that induce larval release behaviors. Pumping behavior was evoked by oligopeptides with a basic amino acid at the carboxy-terminus, preceded by several neutral amino acids. Carboxyl-terminal arginine peptides serve as pheromone mimics. I investigated whether these peptides originate from the action of trypsin-like enzymes by conducting a bioassay measuring pumping activity of ovigerous P. argus subjected to increasing concentrations of trypsin, trypsin inhibitor, and a combination of the two. Pumping activity increased with increasing concentrations of trypsin and trypsin inhibitor, while behaviors ceased when ovigerous females were subjected to a complex of the two. Pheromones are generated by trypsin-like enzymes assisting in the degradation of the egg membranes at the time of hatching. Vertical swimming behaviors of stage-I phyllosoma larvae of P. argus and P. guttatus were observed under laboratory conditions. P. argus larvae displayed a pattern of twilight vertical migration, while P. guttatus larvae displayed nocturnal diel vertical migration (DVM). Rhythms persisted for 5-6 cycles under constant conditions, indicating that an endogenous rhythm in activity plays a proximate role in DVM for both species. / Dissertation

Despite decades of protection, the endangered North Atlantic right whale (Eubalaena glacialis) has failed to recover, primarily due to interactions with fishing gear and ship strikes. Right whales range along the U.S. east coast, foraging year round in the Gulf of Maine while a subset of the population travels to the South Atlantic Bight each year to calve. The habitat requirements of the right whale are poorly understood. I investigated the relationship between the distribution of right whales and physical oceanographic conditions in an effort to create predictive models of essential right whale habitats. Additionally, the distribution of right and humpback whales (Megaptera novaeangliae) relative to fixed fishing gear was examined to assess spatio-temporal overlap. Habitat preferences were assessed using aerial survey data of whale locations and a range of topological and satellite derived physical parameters including bathymetry, sediment type, sea surface temperature, thermal gradients and surface roughness. A suite of non-parametric quantitative techniques including Mantel tests, log likelihood functions, Generalized Additive Models, Spearman Rank Correlations and the Williamson's spatial overlap index were used to assess relationships between whales and habitat variables. Our findings indicate that suitable calving habitat along the east coast may extend much farther to the north than is currently recognized. Our model correctly identified several well documented current and historic calving grounds in the eastern Atlantic but failed to fully identify a heavily used calving area off Argentina, which is characterized by lower surface water temperatures than the other calving regions. In the Gulf of Maine, right whale distribution was correlated primarily with sea surface temperature, sediment type and bathymetry. Predictive models offered insights into right whale habitat preferences for foraging but failed to wholly capture the physical factors underlying right whale distribution. I found the relative density of right and humpback whales and fixed fishing gear in the Gulf of Maine to be negatively correlated in most seasons and areas. These findings demonstrate that the regular co-occurrence of high densities of whales and gear is not a prerequisite for entanglement. Prohibiting entangling lines in areas where whales are known to forage could substantively reduce entanglement. / Dissertation

Snake populations in the North American tallgrass prairie appear to be declining, yet data unavailability impedes the development of enhanced ecological understanding of snake species-habitat relationships and also hinders snake conservation efforts. This study addresses both issues for the snakes of Illinois in two steps. In a two-year mark-recapture study at twenty-two sites within six northern Illinois prairie preserves, I investigated snake species-habitat relationships using habitat variables at three scales: microhabitat (< 100 m), landscape (1 - 10 km), and regional (> 10 km). A total of 120 snakes representing seven species was captured using drift fence arrays associated with funnel traps and sheet metal cover. The low numbers and diversity of snakes captured, when compared to historic evidence, indicate that Illinois snake populations have declined. At the microhabitat scale, non-metric multidimensional scaling and Mantel tests revealed a relationship between snake species composition and elevation. At the landscape-scale, snake species composition varied along an agricultural-urban cover gradient. Classification and regression trees and maximum entropy models (Maxent) were used to identify the scales at which snake species-habitat relationships were strongest. Six of seven regression trees for individual snakes species contained habitat variables at the landscape scale. Important landscape characteristics included patch size, isolation, and land cover, metrics that strongly covary with habitat loss. Microhabitat features only appeared in the regression trees of two species and in three Maxent models. This study indicates that habitat loss has shaped the current distribution of snake species in Illinois's remnant prairies and that snake conservation efforts should emphasize the landscape-scale. Finally, I developed a risk ranking system based on natural and life history characteristics to assess the conservation status of Illinois's 38 snake species. Cluster analysis identified eight groups of snakes, similar in terms of risk factors, with high risk species sharing characteristics such as large body size, long life span, limited habitat breadth, and a high anthropogenic threat ranking. Here, I emphasize the need for basic demographic studies on snakes and suggest that ranking systems be used with population data (when available) and expert opinion to identify snake species of conservation concern in other regions. / Dissertation