Managing Tree-of-Heaven (Ailanthus altissima) in Parks and Protected Areas: A Case Study of Rondeau Provincial Park (Ontario, Canada)

The Carolinian Life Zone in southwestern Ontario, Canada is valued because it represents an almost disjunct ecosystem (i.e., one that is typical of the mid-Atlantic United States, rather than the rest of Canada or the nearby states in the United States). The landscape of the Carolinian Life Zone has undergone dramatic transformation, especially in recent decades as agriculture, urbanization, and recreation have intensified. One of the most apparent changes is the invasion of exotic plant species that exacerbates the need for mass restoration efforts. Within the Carolinian Life Zone, Rondeau Provincial Park has experienced an influx of nonindigenous, invasive species in recent years. Tree-of-heaven (Ailanthus altissima) is one example. The infestation is still relatively localized to (mainly) the park, slowly spreading, and manageable as long as something is done immediately. We examined the effects of hand-pulling and mulching, cut stump and glyphosate application, cut stump alone, and the EZJect Capsule Injection System (using glyphosate) on the management of A. altissima within the park. Cut stump and glyphosate treatment was most effective and efficient in its control of young A. altissima shoots because it limits disturbance and has acceptable capital and operating costs. Hand-pulling and mulching was the second choice, mainly because of the risk of additional disturbance that increased shoot densities 1 year after treatment. Cut stump alone was not effective, worsened the infestation, and is not recommended for this species. The EZJect system was effective at managing mature, seed-producing shoots, although the somewhat higher capital costs mean that the system probably should be purchased for management of several invasive tree species to make it more cost-effective.     

PCB 77 dechlorination products modulate pro-inflammatory events in vascular endothelial cells

Persistent organic pollutants such as polychlorinated biphenyls (PCBs) are associated with detrimental health outcomes including cardiovascular diseases. Remediation of these compounds is a critical component of environmental policy. Although remediation efforts aim to completely remove toxicants, little is known about the effects of potential remediation byproducts. We previously published that Fe/Pd nanoparticles effectively dechlorinate PCB 77 to biphenyl, thus eliminating PCB-induced endothelial dysfunction using primary vascular endothelial cells. Herein, we analyzed the toxic effects of PCB congener mixtures (representative mixtures of commercial PCBs based on previous dechlorination data) produced at multiple time points during the dechlorination of PCB 77 to biphenyl. Compared with pure PCB 77, exposing endothelial cells to lower chlorinated PCB byproducts led to improved cellular viability, decreased superoxide production, and decreased nuclear factor kappa B activation based on duration of remediation. Presence of the parent compound, PCB 77, led to significant increases in mRNA and protein inflammatory marker expression. These data implicate that PCB dechlorination reduces biological toxicity to vascular endothelial cells.     

The Pending Extinction of the Uncompahgre Fritillary Butterfly

Previous mark-recapture studies and population size estimates indicated that in the 1980s populations of the endangered Uncompahgre fritillary ( Boloria acrocnema ) declined precipitously, apparently leading to extirpation at its type locality. This locality and a nearby second site, both high in the San Juan Mountains of southwestern Colorado, constitute the total known range of B. acrocnema . A survey of 20 presumptive allozyme loci from one B. acrocnema population and seven populations of the closely related B. improba , sampled along the Rocky Mountain cordillera from the Yukon Territory, Canada, to the Wind River Range of Wyoming, revealed that B. acrocnema populations are less variable genetically than are B. improba populations in the northern part of that species' North American range. Genetic variability was also assayed at 18 presumptive allozyme loci in populations of Boloria titania, which were sampled from five of the same locations for comparison with the B. improba-B. acrocnema clade. Low estimates of heterozygosity indicate that genetic and demographic factors preceded by historic human disturbance are causing the decline of B. acrocnema . In addition, persistent drought conditions in southwestern Colorado throughout the 1980s probably contributed to the population declines. Conservation recommendations include strict enforcement of the ban against collecting pursuant to the Endangered Species Act, careful monitoring of known B. acrocnema sites, and possible translocations. Extreme measures beyond these will be costly and may be inappropriate for this relict species, which has an unknown capacity to persist in the face of local weather fluctuations and predicted regional warming trends.     

When biologists and engineers collide: Habitat conservation planning in the middle of urbanized development

The City of Austin, Texas, is one of the fastest growing metropolitan areas in the United States. It is also in one of the most biologically diverse terrestrial ecosystems in the world: the Balcones Canyonlands. Five cave invertebrates and two species of birds that inhabit the area are listed as threatened or endangered, two species of plants are candidates for listing, several others are considered rare and of concern, and a species of the salamander has also been proposed for listing. A habitat conservation plan, of national significance according to Secretary of Interior Bruce Babbit (Haurwitz 1996), has been under development for the last several years to conserve those endangered species through a 2400-ha system of preserves and to allow development to continue in more than 162,000 ha of surrounding area. The preserve system, comprising several units ranging in size from less than a hundred to several thousand hectares, would be bordered in many instances by developed areas. Development and maintenance of the infrastructure necessary for new and existing development, both commercial and residential, could have negated the biological value of the preserves (e.g., power-line corridors, water-treatment pipelines and facilities). The challenge of bringing this plan to fruition illustrates the complex biological, technical, and sociological context within which habitat conservation planning may occur. Resolving resource use conflicts of this nature have several commonalities that overarch these contexts. If recognized and addressed, one may move easily and foster positive results. These commonalities can be expressed as principles such as: relying on scientists to recognize, but not solve problems; acting before a scientific consensus is achieved; including human motivation and responses as part of the system to be studied and managed; and confronting uncertainty.     

Leaching of chromated copper arsenate wood preservatives: a review

Recent studies have generated conflicting data regarding the bioaccumulation and toxicity of leachates from preservative-treated wood. Due to the scale of the wood preserving industry, timber treated with the most common preservative, chromated copper arsenate (CCA), may form a significant source of metals in the aquatic environment. The existing literature on leaching of CCA is reviewed, and the numerous factors affecting leaching rates, including pH, salinity, treatment and leaching test protocols are discussed. It is concluded from the literature that insufficient data exists regarding these effects to allow accurate quantification of leaching rates, and also highlights the need for standardised leaching protocols.