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The southern Gulf of St. Lawrence (sGSL) population of Morone saxatilis (Striped Bass) increased over 50 fold between the mid-1990s and 2013–2015, which led to interest in how their feeding might affect populations of commercially and recreation-ally important species. Information on the feeding habits of Striped Bass in all Canadian waters is scarce; therefore, a large number (n = 2220) of sGSL Striped Bass (19–86 cm fork length [FL]) stomachs were collected seasonally (2013–2015) in the Miramichi Estuary (where almost the entire population of individuals >30 cm FL aggregates during spring) and smaller estuaries that empty into the sGSL (summer only), by means of trap nets and by angling. Striped Bass collected during May–early June fed almost exclusively upon Osmerus mordax (Rainbow Smelt) but also consumed a few juvenile Salmo salar (Atlantic Salmon). Striped Bass collected in trap nets during 5–30 June mainly ate a mix of Alosa pseudoharengus (Alewife) and A. aestivalis (Blueback Herring); those collected by angling consumed aquatic insects and Crangon septemspinosa (Sevenspine Bay Shrimp). Striped Bass collected during July–September (30–45 cm FL) ate C. septemspinosa, Palaemon vulgaris (Common Grass Shrimp), and small estuarine fishes. The autumn sample was too small to be considered representative of the population; nevertheless, these fish (32–73 cm FL) ate juveniles of Microgadus tomcod (Atlantic Tomcod), Urophycis tenuis (White Hake), and Gadus ogac (Greenland Cod). The data collected herein would permit reasonable estimates of prey consumed by the sGSL Striped Bass population during spring and, for fish <45 cm total length, during summer, but estimation of annual prey consumption by the sGSL Striped Bass population requires additional data.
A recent data-recovery exercise uncovered a large amount of stomach-content data (n = 8209) from mainly demersal fishes collected seasonally in the Miramichi River Estuary, southern Gulf of St. Lawrence (sGSL), 1991–1993. Of the demersal species captured, all but Pleuronectes putnami (Smooth Flounder) represent transient species. Within the estuary, stomach samples were collected from all species (except Osmerus mordax [Rainbow Smelt]) captured by trawling and in commercial trap nets. Rainbow Smelt stomachs were collected during trawl surveys (May through October) in nearby coastal waters. The summer diet analyses were limited to Smooth Flounder (small bivalve specialist), Pseudopleuronectes americanus (Winter Flounder), and Rainbow Smelt. Many juvenile Urophycis tenuis (White Hake) entered the estuary during late September to feed and then departed during November. Numerous Gadus macrocephalus (Greenland Cod), Myoxocephalus scorpius (Shorthorn Sculpin), Winter Flounder, juvenile Clupea harengus (Atlantic Herring), Microgadus tomcod (Atlantic Tomcod), Rainbow Smelt, Morone saxatilis (Striped Bass), and Zoarces americanus (Ocean Pout) entered the estuary during autumn to overwinter, spawn, and feed. Winter Flounder, Smooth Flounder, Striped Bass, and Atlantic Herring fasted during winter. Crangon septemspinosa (Seven-spined Bay Shrimp) was the most important invertebrate prey (up to 95% of total prey mass) of all transient species. Large specimens of Greenland Cod, Shorthorn Sculpin, Ocean Pout, and White Hake also ate substantial numbers of small Rainbow Smelt, Atlantic Herring, Striped Bass, and Atlantic Tomcod. When combined with published data for the adjacent coastal zone, C. septemspinosa represents a nexus in 2 food webs and fits the description of a keystone species for the sGSL coastal zone and adjacent estuaries.
Herein we synthesize the current understanding of the ecology and distribution of a rarely encountered but broadly distributed dragonfly, Stylurus spiniceps (Arrow Clubtail), and provide new larval records for Maine. Using published and unpublished sources, we construct an account of the distribution, life history, reproductive ecology, and trophic ecology of the Arrow Clubtail, as well as review conservation concerns for the species. We provide new records for the Arrow Clubtail from an atypical habitat—tidal freshwater wetlands—and discuss the importance of these areas for the species. We highlight gaps in our basic natural history knowledge and provide suggestions for future enquiry that could inform conservation measures for this enigmatic dragonfly.
Climate variables affect the phenology of bird migration, and anthropogenic climate change has likely resulted in shifts in these phenological patterns. Warmer springtime temperatures could lead to birds arriving earlier to northerly latitudes in North America. We modeled the effect of temperature with 74 years of data on first arrival for 84 bird species in Worcester County, MA. We found migratory bird species have shifted their arrival to Worcester County an average of 0.11 days per year earlier, with short-distance migrants having stronger shifts (an average of 0.18 days earlier per year) than long-distance migrants (an average of 0.06 days earlier per year). Our results add to a body of literature regarding the potential impacts of climate change on bird migration phenology. We supply support for the notion that some species are temporally shifting their migration in response to warming springtime temperatures. These shifts may be mismatched with resource availability and thus could negatively affect populations and communities. Consequently, it is important to understand patterns in bird migration phenology in order to inform adequate conservation strategies.
Coregonus artedi (Cisco) and Coregonus clupeaformis (Lake Whitefish) are coldwater fishes native to some inland lakes in Wisconsin. We conducted a statewide assessment of Cisco and Lake Whitefish status using experimental-mesh vertical gillnets during the summers of 2011–2014. Cisco and Lake Whitefish relative abundances varied from 0 to 137 and 0 to 3 fish/net night, respectively. About 29% of the Cisco and 33% of the Lake Whitefish populations were potentially extirpated from inland lakes in Wisconsin; most potential extirpations were from southern Wisconsin, but extirpations occurred statewide. Invasive species, climate change, land-use change, and excess nutrient loading may have contributed to causing extirpations of Cisco and Lake Whitefish. Conservation of remaining populations of Cisco and Lake Whitefish will require efforts to minimize these perturbations.
Centaurea stoebe subsp. micranthos (Spotted Knapweed) and the hybrid C. x moncktonii (Meadow Knapweed) are perennial forbs introduced from Europe; the latter also originated from hybridization in North America of 2 other introduced knapweed species. They are invasive in grasslands and pastures in various regions of North America, including increasingly in the Northeast. We collected data from 4 life stages on 11 different demographic rates involving germination, survival, growth, and fecundity. We monitored 4 populations of Meadow Knapweed and 3 populations of Spotted Knapweed over 3 years in New York State by marking and tracking individual plants. Both knapweeds showed moderate to high rates of seed germination, very low survival of dormant seeds, and low survival of early vegetative stages with some site-specific exceptions. Survival of older vegetative and flowering plants was generally moderate to high. The main life-history differences between knapweed taxa involved more rapid maturation to and higher mortality of the flowering stage of Spotted Knapweed, a greater tendency for Spotted Knapweed to alternate between a flowering and vegetative state, and the potential for Meadow Knapweed to grow much larger in size. Spotted Knapweed matured more slowly in New York than in more western populations. Also, the flower head-infesting fly Urophora quadrifasciata and weevils Larinus spp. were present at all study sites. These data add to the knowledge of knapweed demography and can offer insights into the continued expansion and control of these invasive plants.
Overfishing and habitat loss have reduced Pseudopleuronectes americanus (Winter Flounder) populations within the Gulf of Maine (GOM), and despite strict management regulations, abundance is still low. As the GOM continues to warm, there is need to characterize Winter Flounder movements in estuaries to better understand essential habitat use. To characterize movements and habitat use of Winter Flounder, we tagged 17 juvenile flounder (115–170 mm) with acoustic transmitters (Vemco V7-2x) and monitored them using passive tracking over a 4-month period between July and November 2017 in the Saco River Estuary (SRE) in southern Maine. Movement within the SRE was highly variable, with cumulative movements of individual tracked flounder varying between 0 m (e.g., detected only at the release site) and 17,016 m. Tagged flounder were most often present in moderate (15–20 °C) temperatures and salinities (18–26 ppt), and were rarely observed in the highest temperatures (>20 °C) and salinities (>26 ppt). Movements upstream and downstream by flounder appeared to be tidally driven, with most downstream movements occurring during ebb tides and upstream movements during incoming tides. In addition, large flounder moved further away from freshwater, while small flounder either stayed within the river mouth's jetties or moved upstream. The speeds of flounder movements among receiver locations (mean = 4.49 body lengths per second, SE = 0.85) were much faster than expected for flatfish, potentially facilitated by use of tides. The GOM populations of Winter Flounder may benefit from management of juvenile habitat as environmental conditions change.
Fishes have specific dissolved oxygen and water temperature requirements needed to promote optimal growth. Ongoing anthropogenic climate change will lead to increased water temperature and likely changes in dissolved oxygen concentrations that will affect fish populations in a variety of ways. This study uses high-frequency, automated sensor data from 2011–2015 to examine dissolved oxygen and water temperature in Lake Lillinonah, a hydroelectric impoundment in western Connecticut, to identify potentially stressful conditions for Esox lucius (Northern Pike [NP]) and Micropterus salmoides (Largemouth Bass [LMB]). We found that summer water temperature was nearly always in an optimal range for LMB growth, but was frequently in the stressful range for NP growth. In addition, in some years, Lake Lillinonah experienced consistent hypoxia, reducing the thermal refuge available for NP. Long-term data from Lake Lillinonah show an increase in mean July surface water temperature, and further temperature increases are expected as the climate continues to warm. This trend, coupled with a potential reduction in thermal refuge due to hypoxia, poses serious consequences for NP, given that current conditions frequently exceed documented optimal growth range for the species.
Nitrogen is essential in sustaining estuarine ecosystems, particularly lower trophic levels and filter-feeding organisms. However, excess nitrogen is an often-cited cause of coastal ecosystem decline. One of the largest sources of nitrogen in Narragansett Bay, RI, is effluent from wastewater treatment facilities discharging into the head of the Bay. Beginning in 2005, nitrogen reductions at wastewater treatment facilities were implemented to minimize eutrophication and improve water quality. These reductions in nitrogen have led to speculation as to how the Narragansett Bay ecosystem will respond. The filter-feeding clam Mercenaria mercenaria (Quahog) is a prominent component of the Narragansett Bay ecosystem and an economically important resource in Rhode Island. In the northeastern United States, studies of several estuaries have linked nitrogen increases with increased phytoplankton concentrations and faster growth of Quahogs. We evaluated Quahog growth rates to assess how this species has responded to nutrient reductions in the bay. In 2016 and 2017, we collected and aged Quahogs from 6 sites in Narragansett Bay along a gradient of historical nitrogen loading and primary production. We found that Quahog growth rates still vary through space, as previously documented, but despite the recent 50% reduction in nitrogen loading to Narragansett Bay, rates were not significantly different from rates reported for Quahogs collected from 1984 and 2005. Our findings suggest that the reduced nitrogen has not had adverse impacts to Quahog growth, and this information can be used to inform the population's dynamics. However, ecosystem responses to the nutrient reductions are ongoing and the ecology of Quahogs should continue to be monitored to ensure the sustainability of this highly valued commercial and recreational fishery in Narragansett Bay.
Sorex dispar (Long-tailed Shrew) is a rarely collected species typically found along streams and rocky sites with variable vegetation characteristics. Records of this species in New Brunswick have been sparse. Here we report on ecological site characteristics where 13 Long-tailed Shrews were captured over the course of 18,671 trap-nights conducted during 1994–1997 (as part of a larger project) and 2000–2016 in efforts targeting this species. Captures occurred in 3 regions distinct from previous New Brunswick reports: Ganong Ecodistrict, Beadle Ecodistrict, and Meductic Ecodistrict. We document this species in a variety of sites, including sites altered by forest management.
We report 4 occurrences of Lasiurus cinereus (Hoary Bat) on the island of Newfoundland, Canada, based on over 50,000 full-spectrum recordings of echolocation calls made at 94 sites, in Gros Morne National Park, between 2013 and 2019. Our detections of few vocalizations by Hoary Bats over multiple years and locations support prior observations that this species is an infrequent vagrant in western Newfoundland and likely not a summer resident.
Based on samples from 5 discrete habitat types (Thuja occidentalis [Eastern White Cedar] stand, Eastern White Cedar fen, old field, Acadian Mixed Forest, peat bog) we report the first assessment of ant species richness for a specific locale in New Brunswick. We identified 30 ant species across 3 subfamilies and 9 genera as present in Rockwood Park, a heavily wooded, 890-ha municipal park within the city of Saint John. All ant species encountered were native. Given our estimate of a total of 85–96 ant species present in New Brunswick (based on New Brunswick Museum records and studies of ants in northeastern North America), we found ∼35% in Rockwood Park. Major differences were evident in the assemblages of ant species among the 5 habitat types examined. While each habitat included generalist ant species shared across habitat types, ant species unique to each habitat were also present. Of the habitats studied in Rockwood Park, peat bogs and Eastern White Cedar stands supported the ant assemblages that were the most diverse, including several species that have rarely been encountered in North America. Both peat bogs and Eastern White Cedar stands in New Brunswick are widely exploited for commercial purposes. Our results suggest that environmental assessments of such habitats may need to consider the presence of rare, specialist ant species.
Refuge availability is an important component of snake ecology and conservation, yet we have limited understanding of the extent to which snakes use the nests of other animals for refuge. Despite their ubiquity in many forests, the use of ant nests as refuge by snakes has only been reported by a few publications. Between 15 September and 14 October 2019, we set out camera traps to assess whether snakes inhabited active ant mounds and the associated habitats engineered by Formica exsectoides (Allegheny Mound Ant) in northeastern Pennsylvania. We recorded a total of 44 snake images captured at 2 ant mounds, representing 24 individual encounters and 3 snake species. Species observed entering and emerging from mounds included Diadophis punctatus (Ring-necked Snake) and Storeria occipitomaculata (Red-bellied Snake). We observed both Ring-necked Snakes and Red-bellied Snakes briefly entering and exiting nests. The latter was also observed basking outside of a nest, and we observed both species enter a nest without resurfacing. These results suggest that active ant mounds constructed by Allegheny Mound Ants represent an underappreciated resource for these small-bodied snake species.
We report Chaenothecopsis ochroleuca, Haematomma ochroleucum, and Multiclavula vernalis for the first time from Maine. These species are infrequently reported in North America. Our findings are a direct result of lichenology seminars hosted by the Eagle Hill Institute in Steuben, ME.
Little is known about hypogeous, sequestrate fungi (i.e., truffles) in the eastern United States. Since the fruiting bodies of these fungi are part of the diet of multiple rodent species, filling data gaps is important to understanding more about truffle species distribution and habitat associations. During a microhabitat study on radio-collared Glaucomys sabrinus fuscus (Virginia Northern Flying Squirrel) in 2013, we opportunistically sampled truffles at small-mammal digs and scratches within our microhabitat plots. All sampling was conducted within known squirrel-foraging home ranges. We found 3 Elaphomyces species: E. macrosporus, E. verruculosus, and E. americanum. Our observations of E. macroporus are the first from West Virginia. Herein, we describe the microhabitat associations for each fungal species. We suggest using small-mammal digs and scratches as potential indicators to opportunistically gather more information on truffle species in coniferous forests of the eastern United States.
Feeding swarms of dragonflies generally form during prey-accumulation events and can be very large (1000+ individuals), dense, composed of multiple species and both sexes, and persist for hours. In the first published account of such a site from Atlantic Canada, I report the regular, yearly occurrence of large, diverse dragonfly feeding swarms at Black Beach, NB, Canada, in September 2014, 2015, and 2019, and also present the species, sex, and relative ages of specimens collected in swarm surveys. I discuss the significance of Black Beach not only as a feeding site during prey-accumulation events, but also secondarily as a stopover site for migratory species.
Nymphalis antiopa (Mourning Cloak), a common daytime-flying butterfly, is known to exhibit territorial defense against small animals that share the same airspace. However, a bat seems to be an unlikely target for this aggression because bats are potential predators and diurnal bat activity is rarely observed. Here, we report territorial behavior of 2 Mourning Cloaks in response to a diurnally active Eptesicus fuscus (Big Brown Bat). This report is unusual in that it involves a non-predatory cross-phylum interaction, between an insect and a mammal.