Andres B.A.,U.S. Fish and Wildlife Service |
Smith P.A.,Smith and Associates Ecological Research Ltd |
Morrison R.I.G.,Carleton University |
Gratto-Trevor C.L.,Environment Canada |
And 2 more authors.
Wader Study Group Bulletin | Year: 2012
We re-assessed the population size and trend of 52 species and 75 taxa of shorebirds that occur in North America by reviewing published papers, soliciting unpublished data, and seeking the opinions of experts. New information resulted in changing population estimates for 35 of the 71 taxa that could be compared directly to the estimates published in 2006; from this comparison, 28 estimates increased and seven decreased. Almost all of the increases (88%) were the result of more comprehensive surveys being conducted or re-analyses of existing data rather than actual increases in numbers. Retaining the previous estimate was almost always due to a lack of new information. Recent trend analysis indicates that many shorebird populations have stabilized in recent years after large declines during the early 1980s and mid-1990s. Although many shorebird populations listed as threatened or endangered by the U.S. and Canadian governments have increasing population trends, none have reached recovery targets. Information on population trends remains virtually unknown for 25% of the shorebirds occurring in North America, and surveys are needed to determine the state of these populations.
Parsons K.C.,Manomet Center for Conservation science |
Mineau P.,Environment Canada |
Renfrew R.B.,Vermont Center for Ecostudies
Waterbirds | Year: 2010
Waterbird use of agricultural wetlands has increased as natural wetlands have declined. Use of rice (Oryza sativa) habitats by some waterbird species is considered essential to sustaining populations. Although use of rice habitats by waterbirds has been documented throughout the world, little information is available on potential risks as a result of chemicals used in rice cultivation. The current review summarizes understanding of the use and consequences to birds of pesticide applications in rice habitats. Historically, organochlorine pesticides known to be applied for pest management in rice cultivation included dichlorodiphenyltrichloroethane (DDT), aldrin, dieldrin, endrin, heptachlor, technical hexachlorocyclohexane (HCH), toxaphene, endosulfan and sodium pentachlorophenate. Endosulfan and purified HCH (the gamma isomer lindane) are still in use. Cholinesterase-inhibiting insecticides currently used in rice include carbofuran, monocrotophos, phorate, diazinon, fenthion, phosphamidon, methyl parathion and azinphos-methylmany products known to cause acute poisoning in birds. In addition, herbicides, fungicides, molluscicides and other pesticide types are used in rice cultivation. Some of the chemicals are highly toxic to birds and associated with mortality; several have the potential of causing adverse reproductive effects. Because of the large area under rice cultivation worldwide, the volume of pesticides applied to rice fields is significant. Innovations within the past few decades in rice production have increased pesticide use resulting in biodiversity losses in production areas and pollution of water resources. Management practices that address adverse effects of pesticide use in rice fields include increased adoption of Integrated Pest Management principles and less toxic products.
Harrington B.A.,Manomet Center for Conservation science |
Koch S.,U.S. Fish and Wildlife Service |
Niles L.K.,Conserve Wildlife Foundation of New Jersey |
Kalasz K.,The Landing
Waterbirds | Year: 2010
Southward migrating Red Knots (Calidris canutus) were surveyed on Cape Cod, Massachusetts. Unique markers, including ones applied to birds in wintering areas in North and South America, were found. Northern and southern-marked knots had different migration chronologies, plumage characteristics and flight feather molt. Knots from the two groups were found to have different foods and foraging habitats. Numbers of knots more than one year old were found to increase from mid-July to mid-August, decline during late August and then increase in SeptemberOctober. As numbers declined in August, the proportion of knots from South America decreased and, by 1 September, all remaining marked birds had been tagged in North America. Average minimum stopover durations were found to vary according to original banding locations, e.g. 8.5 (±2.6) days for South America, 14.2 (±3.2) days for Delaware Bay, 16.1 (±3.5) days for the U.S. mid-Atlantic coast and 49.5 (±24.6) days for Florida. The proportion of knots with alternate plumage was higher in JulyAugust than in September and by mid-October almost all had basic plumage. Also, low numbers (tens) of basic-plumaged knots-probably one-year-old subadults were found during JulyAugust; most had active flight feather molt. First-arriving juvenile knots were seen beginning in the third week of August and their numbers peaked in mid-September. Differential uses of foraging and roosting habitats were found to be related to migration destinations. Vital habitats that should be managed for protection of threatened Red Knots at this key southward migration stopover area were identified.
Gunn J.S.,Initiative Capital |
Saah D.S.,Spatial Informatics Group |
Hagan J.M.,Manomet Center for Conservation science
Journal of Sustainable Forestry | Year: 2013
Policies based on assumed carbon neutrality fail to address the timing and magnitude of the net greenhouse gas (GHG) changes from using wood for energy. We present a "debt-then-dividend" framework for evaluating the temporal GHG impacts of burning wood for energy. We also present a case study conducted in Massachusetts, USA to demonstrate the framework. Four key inputs are required to calculate the specific shape of the debt-then-dividend curve for a given region or individual biomass facility. First, the biomass feedstock source: the GHG implications of feedstocks differ depending on what would have happened to the material in the absence of biomass energy generation. Second, the form of energy generated: energy technologies have different generation efficiencies and thus different life cycle GHG emissions profiles. Third, the fossil fuel displaced: coal, oil, and natural gas each have different emissions per unit of energy produced. Fourth, the management of the forest: forest management decisions affect recovery rates of carbon from the atmosphere. This framework has broad application for informing the development of renewable energy and climate policies. Most importantly, this debt-then-dividend framework explicitly recognizes that GHG benefits of wood biomass energy will be specific to the forest and technology context of the region or biomass energy projects. © 2013 Copyright Taylor and Francis Group, LLC.
Andres B.A.,U.S. Fish and Wildlife Service |
Johnson J.A.,U.S. Fish and Wildlife Service |
Brown S.C.,Manomet Center for Conservation science |
Lanctot R.B.,U.S. Fish and Wildlife Service
Arctic | Year: 2012
On the Arctic Coastal Plain of the National Petroleum Reserve-Alaska (NPR-A), the Teshekpuk Lake Special Area (TLSA) was recognized to protect outstanding wildlife values. Although information has accumulated on the TLSA's value to caribou and waterfowl, its importance to breeding shorebirds remains largely unquantified. Therefore, we undertook a broad-scale ground study to estimate the population size and density of shorebirds breeding in the TLSA. From a series of plot surveys conducted from 2006 to 2008, we estimated a detection-adjusted total breeding population of more than 573 000 shorebirds and an overall density of 126 shorebirds/km2. Most shorebird species had their greatest densities on the Outer Coastal Plain or had approximately equal densities on Outer and Inner Coastal Plains; only two species had their greatest densities on the Inner Coastal Plain. The greatest densities of breeding shorebirds occurred immediately around Teshekpuk Lake. The TLSA supported more than 10% of the biogeographic populations of black-bellied plover (Pluvialis squatarola), semipalmated sandpiper (Calidris pusilla), and dunlin (C. alpina). Breeding shorebird density in the TLSA is one of the highest in the NPR-A, on Alaska's North Slope, and throughout the circumpolar Arctic. Our results, coupled with previous information on waterfowl and caribou, indicate that the area around Teshekpuk Lake and the recognized goose molting area northeast of the lake should be protected from oil and gas development. © The Arctic Institute of North America.
Saalfeld S.T.,Manomet Center for Conservation science |
Saalfeld S.T.,U.S. Fish and Wildlife Service |
Lanctot R.B.,U.S. Fish and Wildlife Service
Auk | Year: 2015
Shorebirds seem to have evolved a number of strategies for adapting to and exploiting the unpredictable and inhospitable Arctic environment. Two such strategies put forth by Holmes and Pitelka suggest that species either conservatively or opportunistically select breeding locations based on local environmental conditions. "Conservative" species were characterized by strong site fidelity and territoriality, consistent population densities, relatively even spacing of individuals, and monogamous mating systems, while "opportunistic" species exhibited opposite traits and were polygamous. Here, we assessed whether 10 shorebird species consistently exhibited these settlement strategies over a 10-year period (2003-2012) near Barrow, Alaska, by comparing annual estimates of site fidelity, territoriality, and population density. Additionally, we determined the relative importance of past and current environmental and social conditions in predicting annual breeding densities of these same species. Data from 1,413 captured adults and 1,946 shorebird nests indicated that most species conformed to 1 of the 2 settlement strategies, while others exhibited traits of both strategies, and a few had settlement patterns inconsistent with that predicted for their mating system. We suggest that deviations from these strategies may occur depending on a species' location within its breeding range. For some species, however, described settlement patterns may be too simplistic. Species with the same settlement strategy seem to respond similarly to environmental cues but differently than species with the alternative strategy. However, we were unable to determine a common environmental cue for species with the same settlement strategy, although lemming abundance, overall nest survival rate, and presence of conspecifics or heterospecifics did seem to influence settlement decisions in some species. Results from this study indicate that understanding how species settle may have important consequences for implementing monitoring or conservation actions. © 2015 American Ornithologists' Union.
Schulte S.A.,Manomet Center for Conservation Science |
Simons T.R.,U.S. Geological Survey
Marine Ornithology | Year: 2015
We used an information-theoretic approach to assess the factors affecting the reproductive success of American Oystercatchers Haematopus palliatus on the Outer Banks of North Carolina. We evaluated survival with respect to nesting island, year, time of season, brood age, distance to tide (m), presence of off-road vehicles and proximity of foraging habitat. The daily nest survival (mean 0.981, standard error [SE] 0.002) was affected by year and island, and declined over the nesting season. Mammals were responsible for 54% of identified nest failures. Daily brood survival (mean 0.981, SE 0.002) varied by island and increased non-linearly with age, with highest mortality in the seven days after hatching. Model results indicate direct access to foraging sites has a positive effect on brood survival, whereas presence of off-road vehicles has a negative effect. We studied chick behavior and survival using radio telemetry and direct observation and found that vehicles caused mortality and affected behavior and resource use by oystercatcher chicks. We identified the source of mortality for 37 radio-tagged chicks. Six (16%) were killed by vehicles, 21 (57%) by predators, and 10 (27%) by exposure and starvation. From 1995 to 2008, 25 additional oystercatcher chicks were found dead, 13 (52%) killed by vehicles. Chicks on beaches closed to vehicles used beach and intertidal zones more frequently than chicks on beaches open to vehicles. Chick predators included Great Horned Owls Bubo virginianus, Fish Crows Corvus ossifragus, cats Felis catus, mink Mustela vison, raccoons Procyon lotor, and ghost crabs Ocypode albicans. The factors affecting reproductive success differed between the incubation and chick-rearing stages. Management actions that influence chick survival will have a larger effect on total productivity than actions affecting nest survival. © 2015, Marine Ornithology. All rights reserved.
Keeton W.S.,University of Vermont |
Whitman A.A.,Manomet Center for Conservation science |
McGee G.C.,New York University |
Goodale C.L.,Cornell University
Forest Science | Year: 2011
Managing the contribution of forest ecosystems to global carbon cycles requires accurate predictions of biomass dynamics in relation to stand development. Our study evaluated competing hypotheses regarding late-successional biomass dynamics in northern hardwood-conifer forests using a data set spanning the northeastern United States, including 48 mature and 46 old-growth stands. Continuous data on dominant tree ages were available for 29 of these and were used as an indicator of stand development. Aboveground live biomass was significantly (P < 0.001) different between mature (195 Mg/ha) and old-growth (266 Mg/ha) sites. Aboveground biomass was positively (P < 0.001) and logarithmically correlated with dominant tree age; this held for live trees (r2 = 0.52), standing dead trees (r2 = 0.36), total trees (r2 = 0.63), and downed woody debris (r2 = 0.24). In a Classification and Regression Tree analysis, stand age class was the strongest predictor of biomass, but ecoregion and percent conifer accounted for ~25-33% of intraregional variability. Biomass approached maximum values in stands with dominant tree ages of ~350-400 years. Our results support the hypothesis that aboveground biomass can accumulate very late into succession in northern hardwood-conifer forests, recognizing that early declines are also possible in secondary forests as reported previously. Empirical studies suggest a high degree of variability in biomass development pathways and these may differ from theoretical predictions. Primary forest systems, especially those prone to partial disturbances, may have different biomass dynamics compared with those of secondary forests. These differences have important implications for both the quantity and temporal dynamics of carbon storage in old-growth and recovering secondary forests. © 2011 by the Society of American Foresters.
Wilkerson E.,Manomet Center for Conservation science |
Hagan J.M.,Manomet Center for Conservation science |
Whitman A.A.,Manomet Center for Conservation science
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2010
We evaluated the effect of timber harvesting on water quality and macroinvertebrate and periphyton assemblages in first-order streams in Maine, USA. Fifteen streams were assigned to one of five treatments: clearcutting without a stream buffer, clearcutting with 11 m buffers, clearcutting with 23 m buffers, partial harvesting with no designated buffer, and unharvested controls. Harvest blocks on both sides of the stream were 6 ha and partial harvesting within buffers was allowed. Specific conductivity, pH, dissolved oxygen, turbidity, and soluble reactive phosphorus did not change significantly for 3 years after harvesting in all treatments. Unbuffered streams had significantly elevated concentrations of chlorophyll a as well as increased abundance of algal feeding organisms (Diperta Cricotopus and Diptera Psectrocladius). Streams with 11 m buffers had substantial (10-fold) but nonsignificant increases in chlorophyll a. No other significant changes were detected in other treatment groups. In all treatment groups, the dominant taxa (periphyton Achnanthes minutissimum and macroinvertebrate Chironomidae) are adapted to disturbed environments. We attribute the limited harvest-in-duced changes to lack of soil disturbance within 8 m of the stream, the small (≤40%) proportion of watersheds harvested, and the resilient nature of aquatic organisms. However, small-scale changes may not be detected due to the small sample size, an inherent limitation of field-based studies.
Galbraith H.,Manomet Center for Conservation science |
Galbraith H.,National Wildlife Federation |
DesRochers D.W.,Dalton State College |
Brown S.,Manomet Center for Conservation science |
Reed J.M.,Tufts University
PLoS ONE | Year: 2014
Despite an increase in conservation efforts for shorebirds, there are widespread declines of many species of North American shorebirds. We wanted to know whether these declines would be exacerbated by climate change, and whether relatively secure species might become at-risk species. Virtually all of the shorebird species breeding in the USA and Canada are migratory, which means climate change could affect extinction risk via changes on the breeding, wintering, and/or migratory refueling grounds, and that ecological synchronicities could be disrupted at multiple sites. To predict the effects of climate change on shorebird extinction risks, we created a categorical risk model complementary to that used by Partners-in-Flight and the U.S. Shorebird Conservation Plan. The model is based on anticipated changes in breeding, migration, and wintering habitat, degree of dependence on ecological synchronicities, migration distance, and degree of specialization on breeding, migration, or wintering habitat. We evaluated 49 species, and for 3 species we evaluated 2 distinct populations each, and found that 47 (90%) taxa are predicted to experience an increase in risk of extinction. No species was reclassified into a lower-risk category, although 6 species had at least one risk factor decrease in association with climate change. The number of species that changed risk categories in our assessment is sensitive to how much of an effect of climate change is required to cause the shift, but even at its least sensitive, 20 species were at the highest risk category for extinction. Based on our results it appears that shorebirds are likely to be highly vulnerable to climate change. Finally, we discuss both how our approach can be integrated with existing risk assessments and potential future directions for predicting change in extinction risk due to climate change. © 2014 Galbraith et al.