Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact email@example.com with any questions.
Old-growth forests are rare and of conservation concern in Maritime Canada. A variety of methods have been proposed to identify old-growth forests including structural measurements and lichen surveys. Frequency and abundance of Sphaerophorus globosus (Coral Lichen), was measured in 6 old-growth and 6 mature second-growth coniferous forests in Nova Scotia. Total abundance (P = 0.013) and the tree frequency occurrence (P = 0.005) were significantly greater in old-growth forests compared with mature second growth in paired t-tests. We propose the abundance and frequency of occurrence of the easily identifiable lichen Sphaerophorus globosus as an indicator of old-growth forests. Forests with at least 25% of trees having Sphaerophorus globosus growing on them, or meeting the criteria of at least 50 trees/ha with dbh >40 cm and more than 25% of trees with Sphaerophorus globosus, should be studied further as potential candidates for being assigned old-growth forest status.
The introduction of Adelges tsugae (Hemlock Woolly Adelgid [HWA]) to the eastern United States has had a devastating impact on Tsuga canadensis (Eastern Hemlock). Although much research has been done to assess HWA impacts on ecosystem processes and vegetation structure, few researchers have examined community-level changes in highly infested forest stands. Here we assess the impact of Eastern Hemlock mortality on vegetation and invertebrate diversity and community structure by comparing low-impact (healthy) stands and stands heavily impacted by HWA. We sampled the vegetative and invertebrate diversity of 8 sites (4 low impact and 4 high impact) in the summer and fall of 2008. We found a shift in the understory plant community and the canopy and subcanopy arthropod communities. Herbaceous plant species richness was significantly higher at high-impact sites, with Betula lenta (Black Birch) being the most common woody species. Overall, forest invertebrate community diversity (measured using the Shannon-Weaver diversity index) was greater in high- versus low-impact sites. Of the 21 indicator species significantly associated with a given forest type, 14 and 7 species were associated with high- and low-impact forests, respectively. Variation in arthropod community structure was driven by above-ground differences; ground-level arthropod community composition did not differ between high- and low-impact sites. These results demonstrate some of the biodiversity impacts that can result from the invasion of an exotic insect into forested systems.
Seasonal forest pools (SFPs), also known as woodland vernal pools or simply vernal pools, are common throughout the forests of the northeastern United States. SFPs are inundated during all or part of the period between late fall of one year and late spring to mid-summer of the subsequent year. The pools dry every year or at sufficient frequency to preclude the establishment of fish populations, are preferred breeding habitat for a number of amphibian species, and support a rich, diverse, and abundant macroinvertebrate community. These pools exist as aquatic “islands” in a “sea” of forest, and occur over a range of sizes, degrees of isolation, and hydroperiod lengths. As islands, pool area and isolation should affect the composition of biotic communities. The hydroperiod of ephemeral wetlands has been considered a third “island” attribute and is also known to affect biotic composition. We surveyed aquatic, benthic macroinvertebrates (BMIs) for two years using leaf-packs in 24 SFPs, representing a broad range of surface areas, inter-pool distances (isolation), and hydroperiods. Nearly 35,000 specimens of 76 taxa were enumerated from 198 leaf-pack samples. Chironomidae and Oligochaeta were the most abundant and most common taxa. BMI richness and diversity were positively, but weakly, related to maximum pool surface area, but not to pool isolation. The same results were found for permanent resident and predator taxa. BMI richness and diversity were positively related with pool hydroperiod, as reported from numerous other studies of ephemeral aquatic habitats.
Seasonal woodland pools contribute significant biomass to terrestrial ecosystems through production of pool-breeding amphibians. The movement of amphibian metamorphs potentially transports toxins bioaccumulated during larval development in the natal pool into the surrounding terrestrial environment. We documented total mercury (THg) in seasonal woodland pool water, sediment, litter, and Lithobates sylvaticus LeConte (Wood Frog) in Acadia National Park, ME. THg concentrations in pool water varied over the study season, increasing during April—June and remaining high in 2 of 4 pools upon October refill. Water in pools surrounded by softwoods had lower pH, greater dissolved organic carbon, and greater THg concentrations than pools surrounded by hardwoods, with seasonal patterns in sediment THg but not litter THg. THg increased rapidly from near or below detection in 1–2 week old embryos (<0.2 ng; 0–0.49 ppb wet weight) to 17.1–54.2 ppb in tadpoles within 6 weeks; 7.2–42.0% of THg was methyl Hg in tadpoles near metamorphosis. Metamorphs emigrating from seasonal pools may transfer mercury into terrestrial food webs.
Rhamnus cathartica (Common Buckthorn) is a well-established invasive species in North America. We searched early records of the species to help refine this species' history in North America. This note presents strong evidence of Common Buckthorn's entry to North America prior to the 19th century and suggests it was originally imported for medicinal, not ornamental, purposes. We then briefly discuss aspects of its expansion across North America to about the mid-19th century, when it was promoted as a hedge-forming plant. Such information is useful for reconstructing Common Buckthorn's invasion history (including reasons for its success), as well as for understanding human-invasive species interactions in general.
The distribution of below ground biomass within monotypic stands of invasive Phragmites australis (Common Reed) was documented from a series of oligo-, meso-, and polyhaline coastal marshes in New Hampshire. Soil profiles were described, and live biomass was documented growing to a maximum depth of 95 cm for roots and 85 cm for rhizomes. Our data show that invasive P. australis utilizes a greater depth range than native graminoids (90% within the top 70 cm and top 20 cm, respectively). We corroborate prior anecdotal observations and provide further evidence illustrating the potential for this invasive plant to access resources (i.e., water and nutrients) at depths greater than the native species with which it competes.
Since 1993, oyster reef replenishment efforts in the Virginia portion of the Chesapeake Bay have relied heavily on construction of oyster shell reefs with enhanced vertical relief. We evaluated the performance of six reefs constructed in proximity to natural subtidal oyster bars by comparing recruit densities (spat m-2, where spat are young-of-the-year oysters with shell heights less than 50 mm) between habitats. Recruitment was higher on the reefs than bars during the first 1–3 yr post-construction, usually by at least an order of magnitude. Within 7 yr, recruitment was similar between reef-bar pairs although both reefs and bars received additions of shell, live oysters, or both during the study period. At decadal time scales, constructed oyster reefs did not show enhanced recruitment relative to adjacent natural oyster bars. The rapid decline in reef recruitment post-construction is likely related to three processes: (i) shell degradation by taphonomic processes, (ii) biofouling that occludes the shell surface to recruitment, and (iii) inability of extant oysters on the reef to produce new shell at a rate commensurate with losses to (i) and (ii). There appears to be a requirement for continued replenishment activity to maintain the shell base on these reefs, contrary to the dynamics of a healthy natural oyster population. The similarity in recruitment between constructed reefs and natural bars at decadal time scales suggests that subtidal shell plants or shell additions to natural bars may be a more cost-effective repletion strategy because they provide equal population enhancement per unit area.
Very few large-scale studies of breeding marine birds have been conducted in Labrador. To address this information deficit, we conducted near-shore aerial surveys of the Labrador coastline between 6–11 and 21–26 June 2006. Our primary species of interest was Somateria mollissima (Common Eider), for which we counted only adult males. In total, we identified 8 species and 5 species categories (alcid colony, mixed tern and gull colony, etc). In total, we counted 40,700 birds, of which Common Eiders were the most widely distributed species, accounting for 88% of all flock/colony observations. Melanitta perspicillata (Surf Scoter) was the second most abundant species, but had a limited distribution, while Cepphus grylle (Black Guillemot) was the third most abundant species observed, but showed the second widest regional distribution. This information is valuable to resource managers and ecosystem researchers.
In Canada, Lepomis auritus (Redbreast Sunfish) is only found in southwestern New Brunswick, which is the northern limit for the species. In 1989, The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) listed it as a species of special concern due to its limited distribution, and changed the status to data deficient in 2008. The purpose of our study is to begin to build a database of ecological information for the Redbreast Sunfish in New Brunswick. The most northern population occurs in Yoho Lake. Population estimates averaged 386 from 2005 to 2007. The average total length and weight were 12.5 ± 3.1 cm and 42.6 ± 27.3 g, respectively. The length-frequency distributions were consistent over the years, suggesting a stable population structure. Most adult and juvenile sunfish were observed in areas of dense vegetation and large woody debris. Snorkeling surveys were conducted from late June to early July 2005–2007 to assess timing and habitat preference of spawning Redbreast Sunfish. The nests averaged 52.4 ± 10.1 cm in diameter and were 43.9 ± 12.2 cm deep. Nest substrate was sandy with small gravel, and only 33% of the nests were associated with a physical structure in the water column. Overall, the population of Redbreast Sunfish in Yoho Lake appears to be healthy and stable.
Data on food habits of Myotis leibii (Eastern Small-footed Myotis) are scarce. We dissected 172 fecal samples collected from 75 adult (29 males and 46 females) and 2 juvenile (1 male and 1 female) Eastern Small-footed Myotis, captured in mist nets along a forested ridge in northeastern West Virginia in 2008. Fecal samples were dissected and prey items identified to the level of taxonomic order and, when possible, to family. Eastern Small-footed Myotis consumed eight orders of arthropods from 11 families. Lepidoptera (moths) composed 41.5% (±1.9 SE) of adult fecal volume and were found in samples of all 75 adults. Coleoptera (beetles) contributed 30.6 ±1.7% to adult fecal volume and were detected in samples of 97.3% of adults (n = 73). Diptera (flies) composed 16.9 ±1.9% of adult fecal volume and were found in samples of 82.7% of adults (n = 62). Fecal samples of adult females contained a higher percent volume of Lepidoptera (45.9 ± 2.4%, n = 46) than samples of adult males (34.6 ± 3.2%, n = 29). These data provide evidence of moderate dietary specialization on Lepidoptera and demonstrate dietary variation between sexes. Data also indicate Coleoptera and Diptera as important taxonomic groups in the diet of Eastern Small-footed Myotis.
Callophrys irus (Frosted Elfin) is threatened under New York State conservation law and has fewer than 5 secure populations within the state. Published research on these populations is needed to support the development of a state recovery plan and monitoring program for the species. We assessed the relationship between adult occupancy (patch use) in the Albany Pine Bush Preserve and a suite of potential controlling factors. We then used the results in a simulation framework to quantitatively inform how many sites and surveys are needed for Frosted Elfin occupancy monitoring. Patch use was best explained by a model that assumed the same occupancy probability for each patch. The species was more likely to use patches with limited shrub cover and greater host plant density, yet showed a good chance (>76%) of using even the smaller patches (<1 ha) with relatively sparse density (<1000 ramets ha-1). Detection probability depended primarily on observer and survey date, ranging from 0.34 to 0.94 among observers and from 0.35 to 0.96 across surveys. In the worst-case scenario (i.e., low detectability and low intrinsic occupancy rate), minimum effort for adult Frosted Elfin occupancy monitoring in habitat similar to the Albany Pine Bush may require at least 20 habitat patches surveyed 6 times each or at least 10 habitat patches surveyed 8 times each. Less effort (e.g., 10 sites × 4 surveys) will likely suffice if surveys are restricted to the period of peak abundance. Adult occupancy (or patch use) is probably the most efficient state variable for monitoring Frosted Elfin populations, and changes in detection-corrected occupancy rate or proportion of area occupied could be useful for conservation planning.
To maximize reproductive success, parents may differentially invest in sons and daughters, i.e., sex-biased parental investment. Preferential provisioning behavior has been reported in one population of Sialia sialis (Eastern Bluebird) and attributed to local resource competition. We studied the provisioning behavior of Eastern Bluebirds in Madison County, KY in 2004. We experimentally manipulated brood sex ratios in 24 bluebird nests, creating female-biased (n = 8), male-biased (n = 5), and control (n = 11) nests. Following manipulation, nests were videotaped to record adult provisioning behavior. Brood sex ratio had no effect on the provisioning behavior of either male or female Eastern Bluebirds. Similarly, we found no effect of brood sex ratio on the provisioning rates of either male or female bluebirds for control broods that naturally differed in number of male and female nestlings (n = 9; 5 male-biased and 4 female-biased). Our results contrast with those of a previous study that found that male Eastern Bluebirds fed nestling males less than nestling females, possibly because sons were more likely to compete with them for resources in the future. However, local resource competition seems unlikely because Eastern Bluebirds exhibit low rates of philopatry. Given these conflicting results, additional study is needed to determine if factors such as latitude, food availability, or availability of other resources might influence the provisioning behavior of male Eastern Bluebirds.
This paper documents the median spring arrival date of 101 species of Maine migratory breeding birds in 2010 compared to their normal arrival from 1994–2011. The spring of 2010 was uniformly warmer for March, April, and May (monthly departures of 2.0 to 4.0 °C above the mean value). The 101 species showed a strong response to the warm spring, with 86 species arriving earlier, only 12 arriving later, and 3 showing no difference in arrival date from the 17-year median. The strongest response was by leaf-gleaning birds; all 30 species arrived earlier in 2010.
We describe the winter hibernacula of three individual Acris crepitans (Northern Cricket Frogs) around Glenmere Lake in southeastern New York. Frogs were tracked by following fluorescent powder trails of treated Northern Cricket Frogs in late fall 2010. Three frogs were tracked to two subterranean burrows that were 87 m and 140 m from the nearest aquatic habitat. To determine if frogs survived until spring, the burrows were covered by small enclosures in late winter 2011. Northern Cricket Frogs emerged into both enclosures: one frog in one enclosure on 17 March and two frogs into the other enclosure on 10 April. This report confirms the use of subterranean terrestrial habitat distant from water as wintering habitat of Northern Cricket Frogs.
Interspecific killing dissociated from predation is rare in birds. An instance of this behavior episode in which a male Branta canadensis (Canada Goose) killed a Branta bernicla (Brant) was observed and photographed on Long Island, NY in April 2011. The Canada Goose exhibited aggressive nest-defense behavior that is well known for this species, and we suspect that this aggression combined with the Brant's inability to defend itself due to its smaller size led to this unusual result. The male Canada Goose maintained its attack until the Brant died.
A Carcharodon carcharias (White Shark) was observed attacking and successfully taking a male Phocaena phocaena (Harbor Porpoise) in the Bay of Fundy, Canada at 44°52′93″N, 66°44′32″W at 1600 hours on 17 August 2012, between Grand Manan and The Wolves. The shark was estimated to be greater than 3 m in length. This observation is the first of such incident involving a Harbor Porpoise since 1952. This sighting further contributes to the notion that White Sharks prey upon Harbor Porpoise in the Bay of Fundy.