Treesearch

We investigated the effects of repeated prescribed fire, mechanical thinning, and combinations of fire and mechanical thinning on pollinators and flower visitors within the herbaceous understory and midstory of a temperate forest in North Carolina. Using colored pan traps, we sampled flower visitors during the plant growing season between 2014 and 2016. We captured 5,520 flower visitors that were dominated by halictid bees and vespid wasps. Twenty genera of bees representing at least 30 species were captured within our experimental plots. Within the forest understory, we found higher...

Heartwood extractives from Tectona grandis were investigated for antitermitic activities against Heterotermes indicola in laboratory experiments. Extractives were removed from wood shavings by soxhlet extraction using an ethanol: toluene (2:1) solvent system. Termite feeding and mortality followed a concentration dependent response. The highest termite mortality occurred at an extractive concentration of 10 mg/ml. The calculated LC50 based on the concentration dependant response was 3.2 mg/ml. Extractives showed high repellency and antifeedant activity against H. indicola. Tests in which...

Consideration of annual population count data, stream flows, water levels, and nesting habitat availability over a 29-year period suggest that Least Terns (Sternula antillarum athalossos) nesting along the Cheyenne River and Oahe Reservoir in South Dakota, USA, select areas primarily in response to reservoir water levels early in the breeding season. Generalized linear models were selected in an information-theoretic framework and showed important relationships between adult Least Tern numbers and reservoir levels, as well as a negative long-term temporal trend in both survey areas....

Managed and natural coastal plain forests in the humid southeastern United States exchange large amounts of water and energy with the atmosphere through the evapotranspiration (ET) process. ET plays an important role in controlling regional hydrology, climate, and ecosystem productivity. However, long-term studies on the impacts of forest management and climatic variability on forest ET are rare, and our understanding of both external and internal drivers on seasonal and interannual ET variability is incomplete. Using techniques centered on an eddy covariance method, the present study...

Understanding migratory connectivity is fundamental to the ecology, evolution, and conservation of migratory species. The endangered Kirtland’s Warbler (Setophaga kirtlandii) has a restricted breeding range in early successional jack pine (Pinus banksiana) forests with most of the population in northern Michigan and smaller subpopulations in Wisconsin and Ontario. Kirtland’s Warblers spend the winter almost exclusively in the Bahamian Archipelago. Using a combination of visual searches and radiotelemetry, we relocated 89 Kirtland’s Warblers on the breeding grounds that were captured and...

The United States imports more than 1 billion live plants annually—an important and growing pathway for introduction of damaging nonnative invertebrates and pathogens. Inspection of imports is one safeguard for reducing pest introductions, but capacity constraints limit inspection effort. We develop an optimal sampling strategy to minimize the costs of pest introductions from trade by posing inspection as an acceptance sampling problem that incorporates key features of the decision context, including (i) simultaneous inspection of many heterogeneous lots, (ii) a lot-specific sampling...

Collection of morphometric data is an important component in amphibian research, because age-class, body-condition, and demographics yield important insights into populations (Deichmann et al. 2008; Peterman et al. 2008). Snout–vent length (SVL) is one important morphometric measurement that can help deduce age, sex, and when combined with weight, body condition (Kupfer 2007). Thus, accurate measurement of SVL can be critical for obtaining reliable inferences about populations and individuals. For field studies, optimal devices that facilitate accurate measurements would not require...

Concentrations of terrestrially derived dissolved organic matter (DOM) have been increasing in many north temperate and boreal lakes for over two decades. The concentration of DOM in lakes is influenced by a number of environmental factors, but there is still considerable debate about how the availability of terrestrial DOM, and associated dissolved nitrogen and phosphorus, may be affected by drivers of climatic change. Using experimental and observational methods, we considered how changes in soil temperature and moisture affected the composition of carbon, nitrogen, and phosphorus...

The success of classical biological control programs depends in part on understanding climate effects on introduced agents. Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae), a larval endoparasitoid of emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is being introduced to EAB-invaded regions of the United States (USA) and Canada for biological control. To optimize regional release strategies and increase efficiency of the EAB-biocontrol program, we determined the effects of five constant temperatures from 15 °C to 35 °C on T. planipennisi parasitism...

To address uncertainty in biomass estimates across spatial scales, we determined aboveground biomass (AGB) in Californian forests through the use of individual tree detection methods applied to small-footprint airborne LiDAR. We propagated errors originating from a generalized allometric equation, LiDAR measurements, and individual tree detection algorithms to AGB estimates at the tree and plot levels. Larger uncertainties than previously reported at both tree and plot levels were found when AGB was derived from remote sensing. On average, per-tree AGB error was 135% of the estimated AGB,...