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Research output, citation impact, and the most-cited recent papers from Massachusetts Audubon Society (United States). Aggregated across the NobleBlocks index of 300M+ scholarly works.
Top-cited papers from Massachusetts Audubon Society
We used multiple and logistic regression analysis to study the breeding‐area requirements of 10 species of grassland and early‐successional birds at 90 grassland‐barren sites in Maine. The incidence of six of the species was clearly sensitive to the area of grassland. Upland Sandpipers, the species with the largest area requirements, were infrequent at sites of less than 50 ha and reached 50% incidence at those of about 200 ha. Grasshopper Sparrows reached 50% incidence at about 100 ha, Vesper Sparrows at about 20 ha, and Savannah Sparrows at about 10 ha. Incidence for three edge species, Brown Thrasher, Common Yellowthroat, and Song Sparrow, was negatively correlated with open area, and incidence for Field Sparrows was not strongly influenced by grassland size. These results indicate that grasslands need to be approximately 200 ha in area if they are to be likely to support a diverse grass land bird fauna. However, large grasslands or grassland‐barrens are rare; random samples indicated that in Maine only 1% of hayfields and only 8% of grassland‐barrens were more than 64 ha in area. Conservation efforts seeking to protect habitat for rare grassland birds need to consider sites of at least 100 ha—and preferably 200 ha—in size, and these are notably rare in Maine and probably throughout New England and eastern North America. Airports provide some of the last extensive patches of grassland habitat in the northeast. To maintain viable populations of area‐sensitive grassland birds, management of these sites for nesting birds will become increasingly important.
BACKGROUND: Nanocrystalline silver has both antimicrobial and anti-inflammatory properties. However, the exact mechanisms underlying these activities are not known. OBJECTIVES: The objectives of this study were to assess the anti-inflammatory effects of nanocrystalline silver using a murine model of allergic contact dermatitis, compare the effects with those of tacrolimus and a high potency steroid, and to relate the effects to modulation of pro-inflammatory cytokines and apoptosis of inflammatory cells. METHODS: Dermatitis was induced on the ears of BALB/c mice using dinitrofluorobenzene. Topical treatment, including vehicles, 1% nanocrystalline silver cream, tacrolimus ointment and a high potency steroid, was applied once a day for 4 days. Ear swelling was measured and the erythema was evaluated daily. After 4 days of treatment the mice were killed and samples from the ears were collected for histological and immunohistochemical examination, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labelling (TUNEL) staining and extraction of total RNA for reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Significant reductions of ear swelling, erythema and histopathological inflammation in mice ears were observed after 4 days of treatment with 1% nanocrystalline silver cream, tacrolimus ointment or a high potency steroid with no significant difference among them. Both RT-PCR and immunohistochemical staining of sections from ear biopsies demonstrated that nanocrystalline silver, tacrolimus and steroid significantly suppressed the expression of tumour necrosis factor (TNF)-alpha and interleukin (IL)-12. TUNEL staining demonstrated a significant increase in the numbers of apoptotic cells in material from the group treated with nanocrystalline silver when compared with that from groups treated with vehicle, tacrolimus or steroid. CONCLUSIONS: This study demonstrates that nanocrystalline silver inhibits allergic contact dermatitis in mice, similar to steroid and tacrolimus. Nanocrystalline silver suppresses the expression of TNF-alpha and IL-12 and induces apoptosis of inflammatory cells; mechanisms by which nanocrystalline silver may exert its anti-inflammatory effects.
Native antimicrobial peptides and proteins represent bridges between innate and adaptive immunity in mammals. On the one hand they possess direct bacterial killing properties, partly by disintegrating bacterial membranes, and some also by inhibiting functions of intracellular biopolymers. On the other, native antimicrobial peptides and proteins upregulate the host defense as chemoattractants or by various additional immunostimulatory effects. Structure-activity relationship studies indicate that residues responsible for the activities on bacterial membranes or for the secondary functions do not perfectly overlap. In reality, in spite of the relatively short size (18-20 amino acid residues) of some of these molecules, the functional domains can frequently be separated, with the cell-penetrating fragments located at the C-termini and the protein binding domains found upstream. As a cumulative effect, multifunctional and target-specific (agonist or antagonist) antimicrobial peptides and proteins interfere with more than one bacterial function at low concentrations, eliminating toxicity concerns of the earlier generations of antibacterial peptides observed in the clinical setting.
Abstract Assessing the response of salt marshes to tidal restoration relies on comparisons of ecosystem attributes between restored and reference marshes. Although this approach provides an objective basis for judging project success, inferences can be constrained if the high variability of natural marshes masks differences in sampled attributes between restored and reference sites. Furthermore, such assessments are usually focused on a small number of restoration projects in a local area, limiting the ability to address questions regarding the effectiveness of restoration within a broad region. We developed a hierarchical approach to evaluate the performance of tidal restorations at local and regional scales throughout the Gulf of Maine. The cornerstone of the approach is a standard protocol for monitoring restored and reference salt marshes throughout the region. The monitoring protocol was developed by consensus among nearly 50 restoration scientists and practitioners. The protocol is based on a suite of core structural measures that can be applied to any tidal restoration project. The protocol also includes additional functional measures for application to specific projects. Consistent use of the standard protocol to monitor local projects will enable pooling information for regional assessments. Ultimately, it will be possible to establish a range of reference conditions characterizing natural tidal wetlands in the region and to compare performance curves between populations of restored and reference marshes for assessing regional restoration effectiveness.
The chemical nature of nitrogenous compounds in detritus both reflects decay processes and influences rates of detrital decomposition. We followed changes in total, available and refractory nitrogen and amino acids during decay of 6 different species of marine plants and macroalgae. Immobhzation of nitrogen occurred only in detritus derived from Spartina patens, probably because the decay rates of all other species were too rapid to allow mechanisms fostering nitrogen incorporation into detritus to exceed nitrogen losses. In vascular plants, nitrogen in whole detritus and detrital cell walls was lost more slowly than detrital carbon; in marine algae, there was little difference between rates of nitrogen and carbon loss. Ratios of amino acids: total Iutrogen changed very little during decay, suggesting that the chem~cal transformation of amino nitrogen into heterocyclic rings dld not occur. Pools of ava~lable nitrogen, as determined by lability to a bacterial protease and extraction in a neutral detergent, generally declined at a faster rate than pools of refractory nitrogen. In the detntus with the slowest overall rate of organic matter loss, there was little difference between rates of available and refractory nitrogen loss, suggesting that carbon rather than nitrogen was more limiting to decomposers in this species and other vascular plants. In S. alterniflora detritus, the pool of N associated with lignocellulose actually increased in size during decay, probably because nitrogen becomes bound to lignin. A comparison of the decay rates, nitrogen dynamics, and detrital cell wall chemistry of the plants and algae support the central role of detrital chemistry in controlling rates of decomposition and nitrogen turnover.
An ultra-sensitive and highly specific electrical double layer (EDL) modulated biosensor, using nanoporous flexible substrates for wearable diagnostics is demonstrated with the detection of the stress biomarker cortisol in synthetic and human sweat. Zinc oxide thin film was used as active region in contact with the liquid i.e. synthetic and human sweat containing the biomolecules. Cortisol detection in sweat was accomplished by measuring and quantifying impedance changes due to modulation of the double layer capacitance within the electrical double layer through the application of a low orthogonally directed alternating current (AC) electric field. The EDL formed at the liquid-semiconductor interface was amplified in the presence of the nanoporous flexible substrate allowing for measuring the changes in the alternating current impedance signal due to the antibody-hormone interactions at diagnostically relevant concentrations. High sensitivity of detection of 1 pg/mL or 2.75 pmol cortisol in synthetic sweat and 1 ng/mL in human sweat is demonstrated with these novel biosensors. Specificity in synthetic sweat was demonstrated using a cytokine IL-1β. Cortisol detection in human sweat was demonstrated over a concentration range from 10-200 ng/mL.
Abstract It has recently been recognized that mobile colloids may affect the transport of contaminants in ground water. To determine the significance of this process, knowledge of both the total mobile load (dissolved + colloid‐associated) and the dissolved concentration of a ground‐water contaminant must be obtained. Additional information regarding mobile colloid characteristics and concentrations are required to predict accurately the fate and effects of contaminants at sites where significant quantities of colloids are found. To obtain this information, a sampling scheme has been designed and refined to collect mobile colloids while avoiding the inclusion of normally immobile subsurface and well‐derived solids. The effectiveness of this sampling protocol was evaluated at a number of contaminated and pristine sites. The sampling results indicated that slow, prolonged pumping of ground water is much more effective at obtaining ground‐water samples that represent in situ colloid populations than bailing. Bailed samples from a coal tar‐contaminated site contained 10–100 times greater colloid concentrations and up to 750 times greater polycyclic aromatic hydrocarbon concentrations as were detected in slowly pumped samples. The sampling results also indicated that ground‐water colloid concentrations should be monitored in the field to determine the adequacy of purging if colloid and colloid‐associated contaminants are of interest. To avoid changes in the natural ground‐water colloid population through precipitation or coagulation, in situ ground‐water chemistry conditions must be preserved during sampling and storage. Samples collected for determination of the total mobile load of colloids and low‐solubility contaminants must not be filtered because some mobile colloids are removed by this process. Finally, suggestions that mobile colloids are present in ground water at any particular site should be corroborated with auxiliary data, such as colloid levels in “background” wells, colloid‐size distributions, ground‐water geochemistry, and colloid surface characteristics.
It's no secret anymore. Populations of many species of North American grassland birds are declining and have been declining for at least the last 30 years. According to the Breeding Bird Survey (BBS), populations of 13 species of North American grassland birds declined significantly between 1966 and 1996, whereas populations of only 2 species increased during that period (Peterjohn and Sauer 1999). As a group, grassland birds have experienced “steeper, more consistent, and more geographically widespread declines than any other behavioral or ecological guild” (Knopf 1994:251). Those declines appear to be the result primarily of loss and degradation of grassland habitat (e.g. Noss et al. 1995). Not surprisingly, such widespread and consistent declines have stimulated a great deal of recent research attempting to determine the underlying reasons for the declines. Interest in that research has been high, particularly because of the general view that a better understanding of the ecological requirements of grassland birds is needed to help land managers and planners mitigate or reverse some of those declines. Until recently, however, nearly all research has focused on breeding-season events; studies have examined habitat selection and response to management such as prescribed fire and grazing (e.g. Bowen and Kruse 1993, Johnson 1996, Zimmerman 1996, Griebel et al. 1998, Herkert and Glass 1999, Madden et al. 1999, Shriver et al. 1999, Temple et al. 1999, Winter 1999), nest success (e.g. Johnson and Temple 1990, McKee et al. 1998, Hughes et al. 1999, Rohrbaugh et al. 1999), Brown-headed Cowbird (Molothrus ater) parasitism (e.g. Zimmerman 1983, Robinson et al. 1999, Davis and Sealy 2000, Koford et al. 2000, Peer et al. 2000), edge effects (e.g. Helzer 1996, Delisle and Savidge 1997, Jensen 1999, O'Leary and Nyberg 2000, Winter et al. 2000), and area requirements (Herkert 1994, Vickery et al. 1994, Helzer and Jelinski 1999, Winter and Faaborg 1999, Bakker 2000). The paper in this volume by Johnson and Igl (2001) is another important contribution towards a better understanding of how habitat area affects occupancy patterns of grassland birds. Working across a broad geographic region that spans from eastern Montana to western Minnesota, Johnson and Igl sampled breeding grassland birds on 303 grassland patches in 9 counties in 4 northern Great Plains states. Importantly, Johnson and Igl's study design included numerous replicates within each county so that species' area-sensitivity within each county could be assessed separately. Once the county-level analyses were conducted, Johnson and Igl performed a meta-analysis of their data, looking for geographical patterns in area sensitivity and evaluating the effects of species' regional density on patterns of area-sensitivity. Although some of the species Johnson and Igl identify as favoring larger grass patches in one or more counties are the same as those identified in previous work (e.g. Bobolink [Dolichonyx oryzivorus], Baird's Sparrow [Ammodramus bairdii]), Johnson and Igl make the important point that for many of those species, the patterns of area sensitivity they observed differed among regions. For example, only four of six logistic regression coefficients were positive for Bobolinks, and optimal models for only three of six counties analyzed included patch size. Although one might expect habitat selection for species with broad geographic ranges, such as Savannah Sparrow (Passerculus sandwichensis; Wheelwright and Rising 1993) and Grasshopper Sparrow (Ammodramus savannarum; Vickery 1996) to differ from one end of their range to the other, Johnson and Igl's analysis shows that those differences can take place at a scale not previously considered to contain such variability. That variation in patterns of area sensitivity between regions also may explain why some grassland species have been found to be area-sensitive in some previous studies but not others. Understanding what causes differences in species' patterns of area sensitivity is a major conservation need. The fact that Johnson and Igl's study was limited to fields that were part of the Conservation Reserve Program (CRP) underscores another important theme in grassland bird conservation. The CRP is a U.S. federal program to set aside farmland, usually in permanent grass and forb cover, for a period of at least 10 years. Approximately 13.7 million ha are presently enrolled in the CRP (U.S. Department of Agriculture 2000). CRP fields can provide potentially important habitat for grassland birds, but size of each field, seed mixture, and landscape configuration are all likely to influence species composition and may even influence reproductive success (e.g. McCoy 1996, McCoy et al. 1999). Populations of several species of grassland birds appear to have benefited from the establishment of CRP habitat (e.g. Reynolds et al. 1994, Herkert 1997, Herkert 1998). Population trends for Bobolinks, Sedge Wrens (Cistothorus platensis), Dickcissels (Spiza americana), LeConte's Sparrows (Ammodramus leconteii), and Henslow's Sparrows (Ammodramus henslowii) in the United States were all positive since the inception of CRP (1986–1998), reversing earlier population declines in the pre-CRP era (1966–1985; Sauer et al. 1999). Populations of several other species (e.g. Grasshopper Sparrow, Eastern Meadowlark [Sturnella magna], Western Meadowlark [S. neglecta]), however, have continued to decline (Sauer et al. 1999), despite the fact that those species are known to make extensive use of CRP fields (Johnson and Schwartz 1993, Best et al. 1997). Those continued declines point to the complexities in diagnosing population declines and suggest one or more of the following: (1) that the CRP has not provided enough habitat to offset the amount of acreage lost in previous decades; (2) that some, perhaps many, CRP fields are generally too small to benefit certain grassland birds; (3) that although grassland birds occur in CRP fields, those fields may not be productive breeding habitats (i.e. they are possible population sinks); or (4) that problems for some of those species are not limited to the breeding grounds. Determining which of those potential factors continues to limit grassland bird populations should be a high priority for grassland bird conservation. Although the CRP has provided a substantial amount of new grassland habitat, loss of other types of grasslands in the United States has continued unabated. For example, National Resources Inventory data show that between 1982 and 1997, nearly 10.5 million ha of pasture and rangeland were lost in the United States (Natural Resources Conservation Service 2000). Thus, nearly 75% of the current 13.7 million ha in the CRP would be needed to offset the losses that have occurred in other grassland habitats, whereas the net increase in U.S. grasslands as a result of the program has been a modest 3.2 million ha. Additionally, most CRP fields are small, possibly too small to benefit some species of grassland birds. For example, the recently completed 20th CRP sign up (18 January–11 February 2000) included 39,508 contracts comprising 996,047 ha, an average of just 25 ha per contract (U.S. Department of Agriculture 2000). Because some contracts contain more than one field, the mean field size of those contracts is <26 ha. As Johnson and Igl and others in different regions have shown, grassland birds do not generally use grasslands that are small (Herkert 1994, Vickery et al. 1994, Bollinger 1995, Swanson et al. 1999) or poorly configured (i.e. long and narrow; Helzer 1996). Thus, it is clear that many, perhaps most, CRP fields are of limited use to grassland birds because of their small size or poor configuration. In addition to grassland-bird use of particular habitats, information on productivity is also needed to ensure that those areas are not acting as ecological traps (sensu Best 1986) or population sinks (Pulliam 1988). Although studies in other grassland habitats suggest that large sites may be more productive than small sites (e.g. Johnson and Temple 1990, Perkins 1999, Winter and Faaborg 1999, Davis and Sealy 2000), grassland bird productivity in CRP fields can be fairly high (e.g. Berthelsen and Smith 1995, Patterson and Best 1996, Delisle and Savidge 1997, McCoy et al. 1999, Davison and Bollinger 2000) despite their generally small size, and is apparently comparable to that in other grassland habitats (e.g. Koford 1999). Research directed at determining causes of grassland-bird population declines needs to consider the possibility that population problems may be occurring on winter grounds. The wintering ecology of many species is poorly known, however—especially in Mexico and Central and South America—and has been little studied since the work of Grzybowski (1976, 1982, 1983) in Oklahoma. For example, a recent volume on the ecology and conservation of grassland birds in the Western Hemisphere published only 3 winter-season studies versus 23 breeding-season studies (Vickery and Herkert 1999). This imbalance is being rectified, however. Recent published research on wintering grassland birds has covered a variety of issues and geographic regions, including abundance and distribution in CRP and row-crop fields in the Midwest (Best et al. 1998), distribution and habitat use in Mexico (Manzano-Fischer et al. 1999) and Texas (Igl and Ballard 1999), movement patterns and site fidelity in Arizona (Gordon 2000a), and response to management (Chavez-Ramirez and Prieto 1994, Reynolds and Krausman 1998, Gabrey et al. 2000, Gordon 2000b). Importantly, several species that are a high conservation priority, such as Mountain Plover (Charadrius montanus), Henslow's Sparrow, and Dickcissel, have also been studied on their wintering grounds (Chandler and Woodrey 1995, Knopf and Rupert 1995, Plentovich et al. 1998, 1999; Basili and Temple 1999). Although those studies demonstrate that grassland bird winter ecology is an active and important area of inquiry, they must be viewed as initial efforts in a vast, little-explored area of avian ecology. Further studies on wintering ecology and habitat use remain high priorities for grassland bird conservation, as do studies of species that breed at temperate latitudes. Research on the winter ecology of arctic-nesting passerines is generally lacking, although initial efforts to study wintering longspurs (Calcarius spp.), notably Smith's Longspur (C. pictus), are underway (E. Dunn pers. comm.). We hope that work will be extended to Latin America and will incorporate the conservation needs of endemic grassland birds as well (Tubaro and Gabelli 1999).
Journal Article Selective Effects of Predation in a Tern Colony Get access I. C. T. Nisbet I. C. T. Nisbet Massachusetts Audubon Society Lincoln, Massachusetts 01773 Search for other works by this author on: Oxford Academic Google Scholar The Condor, Volume 77, Issue 2, 1 April 1975, Pages 221–226, https://doi.org/10.2307/1365803 Published: 01 April 1975 Article history Accepted: 04 April 1974 Published: 01 April 1975
The composition of local mammalian carnivore communities has far-reaching effects on terrestrial ecosystems worldwide. To better understand how carnivore communities are structured, we analysed camera trap data for 108 087 trap days across 12 countries spanning five continents. We estimate local probabilities of co-occurrence among 768 species pairs from the order Carnivora and evaluate how shared ecological traits correlate with probabilities of co-occurrence. Within individual study areas, species pairs co-occurred more frequently than expected at random. Co-occurrence probabilities were greatest for species pairs that shared ecological traits including similar body size, temporal activity pattern and diet. However, co-occurrence decreased as compared to other species pairs when the pair included a large-bodied carnivore. Our results suggest that a combination of shared traits and top-down regulation by large carnivores shape local carnivore communities globally.
Nesting success of ospreys (Pandion haliaetus) breeding in the Connecticut--Long Island area has increased since 1973 and is now approaching the levels recorded prior to the 1950's. Simultaneously, DDE and dieldrin residues have declined in unhatched eggs. Levels of polychorinated biphenyls have shown no changes over the period 1969 to 1976. The increase in productivity is attributed primarily to lower levels of DDE contamination. Detrimental effects in the past on ospreys in the Connecticut River estuary are attributed to local contamination with dieldrin.
We studied the breeding of 125 pairs of Common Terns (Sterna hirundo) in a large colony at Monomoy, Massaschusetts, in 1979. The colony was subjected to predation by one or more Great Horned Owls (Bubo virginianus). The adult terns deserted the colony for 6.5-8 hours each night throughout the season. Although the owl(s) took no adults and only about 20 chicks from our study plots, the terns suffered unusually heavy losses from other causes, including breakage and disappearance of eggs, hatching failures, attacks by ants (Lasius neoniger), chilling of newly-hatched chicks, and predation by Black-crowned Night-Herons (Nycticorax nycticorax). In a 10-year study, most of these causes of egg and chick loss have been associated with nocturnal desertion and predation by Great Horned Owls. Although nocturnal desertion is effective in minimizing owl predation on adults, it leaves the eggs and chicks vulnerable to chilling and predation. In 1979, both direct and indirect effects of predation fell more heavily on terns that laid in May than on terns that laid in June. Differential predation on early nesters tends to offset other factors that presumably favor early nesting.
Summary A population of 400–600 Acrocephalus orientalis wintering in a Phragmites habitat at 3°N in West Malaysia was studied during four northern hemisphere winters, by means of systematic mist‐netting. Data from other study‐areas, other habitats and other winters are also used. Intensive mist‐netting appears to have made birds move over longer distances than they did in the absence of disturbance, and to have led to the emigration of marked birds from the study‐area. Trapping also affected feeding behaviour, resulting in weight‐loss; repeated trapping may have increased mortality. Males and females could be separated by means of wing‐length in fresh plumage. Females were largely confined to Phragmites; males were more numerous on the edge of reed‐beds and in scrub vegetation. Males suffered greater feather‐wear than females. As measured by the trapping rate, birds were uniformly distributed throughout the Phragmites habitat, at the same density in different winters. Undisturbed birds used a “home‐range” of 1–4 ha, overlapping with 15–50 other individuals. Disturbed birds overlapped with 100–200 others. Individual birds returned to exactly the same “home‐range” in successive winters. After correcting for the effects of disturbance and incomplete sampling, the proportion of adults ringed in one winter which returned in the next is estimated as 65% in each of two study‐areas. This is a minimum estimate of the annual survival rate for adults. Mean total body‐weights were at a minimum in midwinter (November‐February). Fat‐free weights were also lower in midwinter than in autumn and spring. Body‐moult was observed in March and April. Moult of the flight‐feathers takes place between July and September, on the breeding grounds or slightly to the south. Females departed on spring migration between 10 and 25 May; males some 11–14 days earlier. Adults arrived in autumn between 8 September and 7 October; males and females often came in in separate “waves”. Females were absent for only about 127 days, about the minimum required for migration, breeding and moult. Dates of migration match those of the more northern breeding populations. Spring departure is later than dates of passage recorded in south China; hence birds of this population appear to make long nights. On average, birds departing in spring carried about 9 g of fat, roughly 40% of total fat‐free body‐weight. This is about half the energy reserve required for the entire journey. Dates of passage in central China are consistent with a hypothesis that they make the journey (4,500‐5,000 km) in two “hops”. A few birds which remained light until very late in the spring showed a significantly lower return rate in the next year. Most birds arriving in autumn appear to have carried 1–2 g of fat, but some were at or below the normal fat‐free weight. Many birds appear to have lost weight soon after arrival. Returning ringed adults were amongst the very first birds trapped in September. Individual birds appear to have migrated on very similar dates in different years: many of the dates of trapping differed by 2 days or less in successive years. Trapping rates reached a peak in early October and then declined rapidly, reaching the midwinter level by 21 October. The decline coincided with the differential disappearance of juvenile birds. However, birds collected at this time had adequate fat reserves, and the disappearance appears to have preceded the period of food‐shortage. It is suggested that the loss of juvenile birds resulted from behavioural interactions favouring the more dominant individuals, as has been described for several temperate zone residents. The first few weeks in the wintering area may thus be the critical period of mortality during the year. Because birds from different breeding areas are expected to be mixed in the winter‐quarters, and vice versa, local mortality factors in winter may affect a number of breeding populations. High adult survival rates have been recorded in several other birds which breed in the temperate zones and winter in the tropics. In general their breeding success appears to be high, so the first‐year mortality must be high. The closely related A. arundinaceus , which winters in Africa, differs from A. orientalis in size, wing‐shape, timing of spring migration and timing of moult. These differences can be interpreted as adaptations to different environmental (primarily climatic) factors experienced during migration and on the breeding grounds. The segregation of males and females into different habitats probably reduces inter‐sexual competition in winter, but this is not necessarily its primary function. Males collected in the evening in Phragmites had smaller fat reserves than females, suggesting that the females are better adapted to this habitat. The large size of the males is probably maintained in part by sexual selection in the breeding season. On the other hand, the size of females and their habitat is probably limited by the specialisation of their nest. These factors would suffice to explain the sexual dimorphism in size and habitat.
Partners in Flight (PIF) is a consortium of professional and volunteer scientists and educators that promotes the conservation of landbird species. Central to the PIF conservation effort is the development of Bird Conservation Plans specific to each physiographic region of the United States. Without a coordinated prioritization of research needs, land managers, researchers, and funding agencies seeking to conserve landbirds lack direction. To address this issue, we (the Research Working Group of Partners in Flight) identified research priorities that have emerged recently as a result of Bird Conservation Plan development. Research priorities for the coming decade focus on habitat, specifically the identification of high-quality habitats and landscapes for breeding, migration, and wintering. Identification of the scale of breeding and natal dispersal and describing linkages between wintering and breeding populations are also research priorities for the coming decade. A summary of research priorities for each of the PIF regions (Northeast, Midwest, West, and South) is also provided. Specific research needs associated with priority species and habitats in each physiographic area can be accessed in a searchable database: http//www.partnersinflight.org/pifneeds/searchform.cfm.
Abstract The extent to which community college students make the transition from two‐ to four‐year institutions is contingent on the cooperation of these institutions. This chapter examines the creation of transfer centers and other initiatives to address the challenges in the transfer process.
Stomatal size and density are considered two key ecophysiological parameters, because they jointly influence stomatal conductance. In the present study, we examine trends in these anatomical traits along a 660-m elevational gradient on Mt. Moosilauke, in the White Mountains of New Hampshire. Samples were collected from two broadleaf tree species (Betula papayrifera var. cordifolia and Sorbus americana) and two herbaceous understory species (Cornus canadensis and Dryopteris carthusiana). Guard cell length increased with elevation in all four species (all p ≤ .10), but there were no clear elevational trends in stomatal density in any of the four species (all p ≥ .10). A “potential conductance index” [= (guard cell length)2 × stomatal density × 10−4] was positively correlated with elevation for all species, but this trend was significant only for the two understory species (both p ≤ .10). Results are discussed in the context of prevailing theories to explain changes in stomatal traits with elevation.
Since the 1970s, the magnitude of turtle cold-stun strandings have increased dramatically within the northwestern Atlantic. Here, we examine oceanic, atmospheric, and biological factors that may affect the increasing trend of cold-stunned Kemp's ridleys in Cape Cod Bay, Massachusetts, United States of America. Using machine learning and Bayesian inference modeling techniques, we demonstrate higher cold-stunning years occur when the Gulf of Maine has warmer sea surface temperatures in late October through early November. Surprisingly, hatchling numbers in Mexico, a proxy for population abundance, was not identified as an important factor. Further, using our Bayesian count model and forecasted sea surface temperature projections, we predict more than 2,300 Kemp's ridley turtles may cold-stun annually by 2031 as sea surface temperatures continue to increase within the Gulf of Maine. We suggest warmer sea surface temperatures may have modified the northerly distribution of Kemp's ridleys and act as an ecological bridge between the Gulf Stream and nearshore waters. While cold-stunning may currently account for a minor proportion of juvenile mortality, we recommend continuing efforts to rehabilitate cold-stunned individuals to maintain population resiliency for this critically endangered species in the face of a changing climate and continuing anthropogenic threats.
William H. Drury, Jr.; The Breeding Biology of Shorebirds on Bylot Island, Northwest Territories, Canada, The Auk, Volume 78, Issue 2, 1 April 1961, Pages 176–2
More than 70 Common Terns (Sterna hirundo) and lesser numbers of other terns and gulls were killed on 11-12 June 1978, by Paralytic Shellfish Poisoning (PSP; toxin of the dinoflagellate Gonyaulax excavata) at a breeding colony in Massachusetts. PSP toxin was detected at lethal levels in sand-launce (Ammodytes americanus), the terns' principal food. Almost all terns that died were females in pre-laying condition; other birds vomited and survived. Breeding performance of survivors was unaffected. Mortality was greatest in three-year-old birds; 10-25% of three-year-old females were killed. Although PSP toxin was present in local shellfish for about three weeks, tern mortality was limited to a few hours on two days. Much higher levels of toxin were detected in shellfish at other parts of the Massachusetts coast in 1978 and other years, but terns and other susceptible seabirds were unaffected.
The Park/School Program was developed by the Urban Resources Initiative at the Yale School of Forestry and Environmental Studies in cooperation with school teachers and urban park rangers. During the pilot project, graduate students in environmental studies conducted field studies in ecology with 46 fifth graders to introduce them to natural resources and to develop social skills in a neighborhood park. The process of developing teamwork through cooperative games and group projects, of increasing understanding of urban ecosystems through outdoor investigations and indoor laboratory activities, and of applying the teamwork and understanding to teaching others instilled in the children a sense of ownership and internalization of their knowledge of the park. The program succeeded in its aims of increasing ecological knowledge and improving the social skills of the students. Unanticipated outcomes included the changing perceptions of teachers and students toward each other, of the park, and students' perceptions of themselves. An overview of the pilot project, its potential for effecting change inside and outside the classroom, and recommendations for future programs and research are presented.