Simulated Herbivory and Vegetation Dynamics in Coal Slurry Ponds Reclaimed as Wetlands

The biodiversity of coal slurry ponds can be inhibited, at least in part, by dense stands of Phragmites australis. In this study, we demonstrate that species richness can be increased in coal slurry ponds if the dominant species (P. australis and Typha latifolia) are removed and that underwater herbivory simulated by cutting will kill emergents. The study was conducted in the greenhouse and the field in both flooded and drawndown conditions. Stems of plants of P. australis and T. latifolia were cut in a greenhouse and the cut plants of both species showed a decline in survivorship (25 and 42% survival, respectively) whereas all uncut plants survived. In a reclaimed coal pond at Pyramid State Park, Illinois, neither P. australis nor T. latifolia survived cutting underwater, but all of the uncut plants survived. Regrowth measured as total biomass of stems was less among flooded versus freely drained plants (0.3 and 2.6 g biomass, respectively). Cut versus uncut plants, combining freely drained and flooded, had less below-ground biomass (99.4 and 254.4 g, respectively). In the greenhouse study, oxygen levels in rhizomes subsequent to cutting were measured using an oxygen electrode and millivolt meter. Oxygen levels in P. australis were lower in cut versus uncut plants both in flooded (15.0 vs. 16.3% ambient O₂, respectively) and freely drained conditions (14.5 vs. 15.0%, ambient O₂, respectively). Similar responses to cutting were demonstrated by T. latifolia. In an unreclaimed coal slurry pond with monospecific stands of P. australis, plant species richness increased in cut plots as compared to uncut plots (29 vs. 2 species, respectively) between March and September, 1995. This study demonstrated that species richness can be increased in coal ponds by mechanical cutting and this potentially by herbivory; however, the additional species were mostly exotics.     

Seed Banks and Species Richness Potential of Coal Slurry Ponds Reclaimed as Wetlands

Seed bank experiments are described to assess the species richness potential of coal slurry ponds reclaimed as wetlands (ranging from 6 to more than 40 years old). Experimental treatments test the drawdown and flooded conditions characteristic of the vegetation dynamics of emergent wetlands in the Upper Mississippi Valley. More seedlings, primarily annuals, emerged from exposed wet sediments (freely drained) than under continuous flooded sediments in cold ponds (339 versus 136 seedlings m^?2, respectively) and in natural ponds (163 versus 47, respectively). More seeds were produced by plants established in freely drained conditions than under flooded conditions from sediments in the coal ponds (26546 versus 1842 seeds m^?2, respectively) and the natural ponds (28430 versus 4526, respectively). Similarly, more biomass was also produced by these plants in freely drained than under flooded conditions in coal ponds (118 versus 47 g m^?2, respectively) and natural ponds (118 versus 52, respectively). Fertilization (NPK) did not affect germination for the most part, but it did affect seed set and biomass production, especially for C₄ annuals such as Echinochloa crusgalli and Panicum dichotomiflorum. I propose that lime (calcium carbonate) and fertilizer be applied during the first few scheduled drawdowns for these coal slurry ponds reclaimed as wetlands to increase the number of species and to allow their more rapid development as self-sustaining systems.     

Avian Nest Box Selection and Nest Success in Burned and Unburned Southwestern Riparian Forest

ABSTRACT Riparian forest communities in the southwestern United States were historically structured by a disturbance regime of annual flooding. In recent decades, however, frequency of flooding has decreased and frequency of wildfires has increased. Riparian forests provide important breeding habitat for a large variety of bird species, and the effects of this altered disturbance regime on birds and their breeding habitat is largely unknown. To evaluate effects of high-intensity spring and summer wildfire on the quality of breeding bird habitat in the Middle Rio Grande valley, we measured vegetation structure and composition, avian nest use, and nest success at 4 unburned plots and 4 wildfire plots over a 3-year period. We measured avian nest use and success at nest boxes located in unburned riparian forest plots and plots recently burned by wildfire. Recent wildfire plots (<7 yr after fire) had a much different vegetation structure than unburned plots; an older (>7 yr after fire) wildfire plot more closely resembled its paired unburned plot than did recently burned plots. Ash-throated flycatchers (Myiarchus cinerascens) and Bewick's wrens (Thryomanes bewickii; hereafter, flycatchers and wrens, respectively) used nest boxes in most of the plots. A model selection procedure applied to logistic regressions showed that frequency of nest box use by flycatchers was positively associated with wildfire, although flycatchers used boxes in unburned plots as well. Wrens showed a preferential use of nest boxes that were in unburned sites and in close proximity to vegetative cover. Growth rates, feeding rates, and fledging mass of flycatchers were similar in wildfire and unburned plots. Growth rates for wrens were slower in wildfire plots, while feeding rates and fledging mass were similar. Nest predation varied between years, was higher for flycatchers than for wrens, and was not directly influenced by wildfire. Model selection showed that predation increased with grass cover, an indicator of forest openness, and decreased with distance to habitat edge. Recovery of dense vegetation appears important in maintaining populations of Bewick's wrens, whereas ash-throated flycatchers were less sensitive to vegetative structure and composition of postfire succession. Postfire management that maintains nest sites in large forest strips would enhance nesting density and success of these cavity-nesting birds in riparian zones.     

Use of Restored Small Wetlands by Breeding Waterfowl in Prince Edward Island, Canada

Abstract Since 1990 under the Eastern Habitat Joint Venture over 100 small wetlands have been restored in Prince Edward Island, Canada. Wetlands were restored by means of dredging accumulated sediment from erosion to emulate pre‐disturbance conditions (i.e., open water and extended hydroperiod). In 1998 and 1999 we compared waterfowl pair and brood use on 22 restored and 24 reference wetlands. More pairs and broods of Ring‐necked Ducks, Gadwall, Green‐winged Teal, and American Black Ducks used restored versus reference wetlands. In restored wetlands waterfowl pair density and species richness were positively correlated with wetland/cattail area, percent cattail cover, and close proximity to freshwater rivers. In addition, a waterfowl reproductive index was positively correlated with percent cattail cover. Green‐winged Teal pair occurrence in restored wetlands was positively correlated with greater amounts of open water and water depths. American Black Duck pairs occurred on most (86%) restored wetlands. Restored small wetlands likely served as stopover points for American Black Duck broods during overland or stream movements, whereas they likely served as a final brood‐rearing destination for Green‐winged Teal broods. We suggest that wetland restoration is a good management tool for increasing populations of Green‐winged Teal and American Black Ducks in Prince Edward Island.     

Eutrophication and Bacterial Pathogens as Risk Factors for Avian Botulism Outbreaks in Wetlands Receiving Effluents from Urban Wastewater Treatment Plants

Due to the scarcity of water resources in the “Mancha Húmeda” Biosphere Reserve, the use of treated wastewater has been proposed as a solution for the conservation of natural threatened floodplain wetlands. In addition, wastewater treatment plants of many villages pour their effluent into nearby natural lakes. We hypothesized that certain avian pathogens present in wastewater may cause avian mortalities which would trigger avian botulism outbreaks. With the aim of testing our hypothesis, 24 locations distributed in three wetlands, two that receive wastewater effluents and one serving as a control, were monitored during a year. Sediment, water, water bird feces, and invertebrates were collected for the detection of putative avian pathogenic Escherichia coli (APEC), Salmonella spp., Clostridium perfringens type A, and Clostridium botulinum type C/D. Also, water and sediment physicochemical properties were determined. Overall, APEC, C. perfringens, and C. botulinum were significantly more prevalent in samples belonging to the wetlands which receive wastewater. The occurrence of a botulism outbreak in one of the studied wetlands coincided with high water temperatures and sediment 5-day biochemical oxygen demand (BOD₅), a decrease in water redox potential, chlorophyll a, and sulfate levels, and an increase in water inorganic carbon levels. The presence of C. botulinum in bird feces before the onset of the outbreak indicates that carrier birds exist and highlights the risk of botulinum toxin production in their carcasses if they die by other causes such as bacterial diseases, which are more probable in wastewater wetlands.     

Phenazine Methosulfate; its Use in Evaluating Activity of Dehydrogenase Systems of Avian Liver

Lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and suecinate dehydrogenase were demonstrated in livers of 15-day chick embryos. The addition of phenazine methosulfate (PMS) to the LDH and MDH incubation mixtures reduced diformazan deposition in the liver epithelium but not in connective tissue. A 30 sec formalin fixation, absence of PMS, or the addition of sodium azide or potassium cyanide to the PMS-containing incubation mixtures facilitated formazan deposition. These results are explained by assuming that, in the absence of PMS, dehydrogenase activity is demonstrated via endogenous diaphorase. When PMS is present, Nitro BT reduction occurs within the incubation mixture. A side effect of the azide or cyanide is an interference with, the action of PMS, thus allowing diformazan deposition via the endogenous diaphorase when this is present in the tissue.     

Non‐Redundant Social Information Use in Avian Flocks with Multisensory Stimuli

Animals generally live in multisensory worlds; however, our understanding of multisensory perception is rather limited, despite its relevance for explaining the mechanisms behind social interactions, such as collective detection while foraging in groups. We tested how multisensory stimuli affected the antipredator behavior of dark‐eyed juncos (Junco hyemalis) using alarm calls as an auditory signal and flushing behavior as a visual cue. We varied the degree of risk within the group by manipulating the number of group mates alarm calling and/or flushing using robotic birds. We assumed that alarm calling and flushing were redundant stimuli and predicted that they could generate one of three types of responses (enhancement, equivalence, or antagonism) depending on the mechanism of multisensory perception. We set up an artificial flock with three robotic juncos surrounding a live junco and controlled for multiple confounding factors (e.g., identity of the focal, body mass, food deprivation time). We found that the degree of alarm of live juncos increased when at least one robot flushed. However, the time it took the live individuals to react to the robots' behavior increased, rather than decreased, with at least one alarm call. This could be the result of an orienting response or sensory overload, as live juncos increased scanning behavior after being exposed solely to alarm calls. Contrary to some theoretical assumptions, alarm calling and flushing behavior elicited independent unimodal responses, suggesting that they are non‐redundant stimuli and that together they could reduce the occurrence of false alarms and facilitate flock cohesion.     

上海崇明东滩堤内次生人工湿地鸟类冬春季生境选择的因子分析

2004年12月—2005年5月,对上海崇明东滩98海堤内200hm2次生人工湿地进行鸟类调查,在冬季统计到鸟类8目15科56种,以游、涉禽为主;在春季统计到鸟类10目19科55种,以涉禽为主。运用多元回归对鸟类种类数、数量、物种多样性、均匀性指数和科属多样性等群落特征以及调查样点内水位、水面积、植被盖度、底栖动物密度、鱼类捕捞和人类干扰等环境因子进行鸟类生境选择分析。回归模型显示冬季鸟类种类数与植被盖度呈显著正相关,鸟类数量、物种多样性、科属多样性等群落特征与水位高低、水面积比例以及鱼类捕捞强度等有关,底栖动物密度影响鸟类均匀度和数量;春季鸟类数量与鱼塘的水面积呈正相关,而种类和数量与水位呈显著负相关,物种多样性和均匀性明显受水位、水面积和植被盖度影响,鸟类科属多样性与底栖动物密度呈显著相关,捕捞状况对春季鸟类群落影响不大。     

Carbon Sequestration in Reclaimed Minesoils

Minesoils are drastically influenced by anthropogenic activities. They are characterized by low soil organic matter (SOM) content, low fertility, and poor physicochemical and biological properties, limiting their quality, capability, and functions. Reclamation of these soils has potential for resequestering some of the C lost and mitigating CO₂ emissions. Soil organic carbon (SOC) sequestration rates in minesoils are high in the first 20 to 30 years after reclamation in the top 15 cm soil depth. In general, higher rates of SOC sequestration are observed for minesoils under pasture and grassland management than under forest land use. Observed rates of SOC sequestration are 0.3 to 1.85 Mg C ha^{? 1} yr^{? 1} for pastures and rangelands, and 0.2 to 1.64 Mg C ha^{? 1} yr^{? 1} for forest land use. Proper reclamation and postreclamation management may enhance SOC sequestration and add to the economic value of the mined sites. Management practices that may enhance SOC sequestration include increasing vegetative cover by deep-rooted perennial vegetation and afforestation, improving soil fertility, and alleviation of physical, chemical and biological limitations by fertilizers and soil amendments such as biosolids, manure, coal combustion by-products, and mulches. Soil and water conservation are important to SOC sequestration. The potential of SOC sequestration in minesoils of the US is estimated to be 1.28 Tg C yr^?1, compared to the emissions from coal combustion of 506 Tg C yr^{? 1}.     

Anion fluxes in three Indiana forests

Summary The major ions in soil solution in control and disturbed plots were measured over a year in three Indiana forests. The major ions in bulk precipitation were hydrogen and sulfate. Sulfate, calcium, and magnesium were the most important ions in the soil solution in control plots, while in disturbed plots nitrate, calcium, and magnesium were most important. Increase nitrate production and loss following disturbance caused a large increase in cation losses.     

The epiphytology of spearmint rust in Indiana

Summary Field studies indicated that subterranean aecia ofPuccinia menthae Pers. are of little significance in the initiation of spearmint rust infection in undisturbed fields. Also, wild or escaped mints do not appear to be of significance. The primary source of inoculum comes either from fields that are not fall plowed or from infected rhizomes or transplants during spring planting. Temperatures during May appear to be critical in the development of rust epiphytotics. The predominant race of the pathogen occurring in Indiana corresponds to Race 1.Respectively, former graduate research assistant, Department of Botany and Plant Pathology, Purdue University, presently Assistant Plant Pathologist, University of Arizona, Mesa Branch Experiment Station, Mesa, Arizona; and Associate Plant Pathologist, Department of Botany and Plant Pathology, Purdue University, Lafayette, Indiana. Journal paper 2691. The authors thank Dr.M. J. Murray, A. M. Todd Company, Kalamazoo, Michigan, for species ofMentha used as race differentials. This research was supported, in part, by funds provided through the Mint Industries Research grant.     

Dispersal Characteristics of Juvenile Bobcats in South-Central Indiana

ABSTRACT Bobcat (Lynx rufus) populations in the Midwestern United States experienced historic declines due to habitat loss and exploitation but have rebounded in recent decades. We investigated natal dispersal of juvenile bobcats from a population in south-central Indiana, USA, from 1999 to 2006. We radiocollared 16 juvenile bobcats (11 M, 5 F) and monitored them for 237–1,014 days (x̄ = 506). One female (20%) and 11 males (100%) dispersed from natal home ranges that averaged 14.6 km² in size. Most juveniles (70%) initiated dispersal from mid-February through March, late in their first year. Only 5 bobcats (42%) ultimately established a final home range 63 ± 35 km² in size 13–92 km (x̄ = 44) from their natal range 140 ± 45 days after initiating dispersal. Survival did not differ (P = 0.93) between dispersing (S = 0.73) and philopatric (S = 0.75) individuals, although 4 bobcats (3 M, 1 F) were killed in collisions with vehicles. We found dispersal of bobcats in fragmented landscapes is prolonged and often unsuccessful; the ability of dispersers to locate suitable vacant habitat patches may be vital to the continued growth of bobcat populations recolonizing the agricultural Midwest.     

Stability of Avian Fecal Corticosterone Metabolite Levels in Frozen Avian Feces

ABSTRACT Fecal corticosterone metabolites are commonly used in avian ecology as a measure of response to stress. Recent research on mammals suggested that the manner in which samples are stored could be critical to alleviating any storage handling bias. Cross-reacting metabolites can increase glucocorticoid metabolites even after samples are frozen and, thus, result in an overestimation of hormone levels as the time increases between when samples were collected and when levels are measured. We examined effects of sample storage time on fecal corticosterone metabolites for 2 avian species across 165 days. We observed no change in fecal corticosterone metabolites across the sampling periods in either fulvous whistling-ducks (Dendrocygna bicolor) or white ibis (Eudocimus albus). Results suggest that avian fecal corticosterone metabolite levels do not change when samples are frozen for long periods of time and that there were no differences in the response between the 2 species we compared. This study demonstrated that avian fecal corticosterone samples are accurate even after freezing and, thus, studies that seek to address conservation questions may rely on these data. Studies of additional bird species are needed to generalize our findings to other avian taxa.