David I. King

Productivity of early successional shrubland birds in clearcuts and groupcuts in an eastern deciduous forest

Uneven-aged forest management has been advocated as a silvicultural practice because of concerns about the negative effects of even-aged management on birds that dwell in mature forests. Recent evidence, however, indicates that in the northeastern United States, bird species that inhabit early successional habitats may be experiencing more widespread declines than their mature-forest counterparts. We compared the effect of group selection, a widely used form of uneven-aged forest management, and clearcutting on nest survival rates of early successional shrubland birds in the White Mountains of New Hampshire. There was no difference in daily nest survival rate between clearcuts (0.990) and groupcuts (0.987) for 16 bird species combined (n = 290), and no difference in daily nest survival rate between clearcuts (0.993) and groupcuts (0.987) for chestnut-sided warblers (Dendroica pensylvanica), the only species for which enough nests were found for separate analysis (n = 217). There was no difference in daily nest survival rates of all species combined between edge (0.983) and interior areas (0.992) of clearcuts (n = 204), and no difference in daily nest survival rates of chestnut-sided warblers between edge (0.984) and interior (0.993) areas of groupcuts (n = 156). Thus, our results suggest that clearcuts and groupcuts provide similar habitat for species of early successional shrubland birds that inhabit both clearcuts and groupcuts. Recent studies, however, indicate that some bird species that use larger openings such as clearcuts do not occupy smaller openings created by group selection, which may limit the utility of group selection in managing habitat for early successional shrubland birds.

Scrub-shrub bird habitat associations at multiple spatial scales in beaver meadows in Massachusetts.

Abstract.— n Most scrub-shrub bird species are declining in the northeastern United States, and these declines are largely attributed to regional declines in habitat availability. American Beaver (Castor canadensis; hereafter “beaver”) populations have been increasing in the Northeast in recent decades, and beavers create scrub-shrub habitat through their dam-building and foraging activities. Few systematic studies have been conducted on the value of beaver-modified habitats for scrub-shrub birds, and these data are important for understanding habitat selection of scrub-shrub birds as well as for assessing regional habitat availability for these species. We conducted surveys in 37 beaver meadows in a 2,800-km2 study area in western Massachusetts during 2005 and 2006 to determine the extent to which these beaver-modified habitats are used by scrub-shrub birds, as well as the characteristics of beaver meadows most closely related to bird use. We modeled bird abundance in relation to microhabitat-, patch-, and landscape-context variables while adjusting for survey-specific covariates affecting detectability using N-mixture models. We found that scrub-shrub birds of regional conservation concern occupied these sites and that birds responded differently to microhabitat, patch, and landscape characteristics of beaver meadows. Generally, scrub-shrub birds increased in abundance along a gradient of increasing vegetation complexity, and three species were positively related to patch size. We conclude that these habitats can potentially play an important role in regional conservation of scrub-shrub birds and recommend that conservation priority be given to larger beaver meadows with diverse vegetation structure and composition.

Decline of a New Hampshire Bicknell's Thrush Population, 1993–2003

Abstract Catharus bicknelli (Bicknells Thrush) is a rare inhabitant of mountain forests in the northeastern United States and southeastern Canada. Conservation planners consider the species to be at risk, although evidence of population decline has thus far been localized or inconclusive. In order to assess the status of Bicknells Thrush in the White Mountains of New Hampshire, we conducted point-count surveys on 40 forested, high-elevation routes from 1993 to 2003. Non-linear regression on aggregate counts revealed a 7% annual decline over this period (P < 0.1). We discuss possible threats to Bicknells Thrush, including winter habitat loss, pollution of mountain ecosystems, climate change, and human intrusion during breeding. A range-wide monitoring program that incorporates new survey methods is needed to help identify limiting factors and reduce potential sources of error and bias. This study underscores the importance of efforts to monitor and conserve Bicknells Thrush.

Population trends influence species ability to track climate change

Shifts of distributions have been attributed to species tracking their fundamental climate niches through space. However, several studies have now demonstrated that niche tracking is imperfect, that species climate niches may vary with population trends, and that geographic distributions may lag behind rapid climate change. These reports of imperfect niche tracking imply shifts in species realized climate niches. We argue that quantifying climate niche shifts and analyzing them for a suite of species reveal general patterns of niche shifts and the factors affecting species ability to track climate change. We analyzed changes in realized climate niche between 1984 and 2012 for 46 species of North American birds in relation to population trends in an effort to determine whether species differ in the ability to track climate change and whether differences in niche tracking are related to population trends. We found that increasingly abundant species tended to show greater levels of niche expansion (climate space occupied in 2012 but not in 1980) compared to declining species. Declining species had significantly greater niche unfilling (climate space occupied in 1980 but not in 2012) compared to increasing species due to an inability to colonize new sites beyond their range peripheries after climate had changed at sites of occurrence. Increasing species, conversely, were better able to colonize new sites and therefore showed very little niche unfilling. Our results indicate that species with increasing trends are better able to geographically track climate change compared to declining species, which exhibited lags relative to changes in climate. These findings have important implications for understanding past changes in distribution, as well as modeling dynamic species distributions in the face of climate change.

Plumage coloration and reproductive success in male chestnut-sided warblers

Abstract We studied Chestnut-sided Warblers (Dendroica pensylvanica) to determine whether there exists any relationship between plumage coloration and reproductive success in this species. We observed that males with more extensive chestnut breast coloration initiated nests significantly earlier than males with less chestnut, and had marginally larger clutch sizes as well. However, there was no significant relationship between the number of young fledged or the condition of the young and the extent of chestnut breast coloration, nor were there any significant relationships between any of these measures of reproductive success and the extent of yellow crown coloration. The extent of chestnut coloration on the breast was significantly less for males in their first breeding season, suggesting that the relationships between the extent of breast coloration and reproductive success may reflect age specific differences in these parameters.

Montane birds shift downslope despite recent warming in the northern Appalachian Mountains

AbstractMontane regions support distinct animal and plant communities that are widely viewed as communities of high conservation concern due to their significant contribution to regional biodiversity. These communities are also thought to be particularly vulnerable to anthropogenically caused stressors such as climate change, which is generally expected to cause upward shifts and potential range restrictions in montane plant and animal distributions. In the northern Appalachian Mountains of North America, not only is it becoming warmer at mid-elevations but the ecotone between the northern hardwood and the montane coniferous forests is also shifting. Therefore, species that are limited by climate or habitat along the elevational gradient of mountains may also be experiencing distributional shifts. We studied birds along replicate elevational gradients in the White Mountains of New Hampshire, USA, from 1993 to 2009 and used mixed effects models to estimate the rate of elevational change to test the hypothesis that northern hardwood forest- and montane forest-dependent birds are shifting upslope, consistent with climate change predictions. As predicted, the upper elevational boundary of 9 out of 16 low-elevation species showed evidence of shifting upslope an average of 99xa0m over the course of the study period. Contrary to our expectations, 9 out of 11 high-elevation species had lower elevational boundaries that shifted downslope an average of 19xa0m. The opposing elevational shifts of two distinct and adjacent bird communities is, to our knowledge, unprecedented and highlights the need for caution when applying conventional expectations to species’ responses to climate change.ZusammenfassungTrotz aktueller Erwärmung verlagern Gebirgsvögel in den nördlichen Appalachen ihr Vorkommen hangabwärtsn Bergregionen beherbergen besondere Tier- und Pflanzengemeinschaften, die aufgrund ihres erheblichen Beitrags zur regionalen Biodiversität weithin als Gesellschaften mit hohem Schutzbedarf betrachtet werden. Diese Artengemeinschaften gelten auch als besonders anfällig für anthropogen verursachte Stressfaktoren wie den Klimawandel, von dem allgemein angenommen wird, dass er Verschiebungen in höhere Lagen und potenzielle Beschränkungen des Verbreitungsgebietes für Gebirgspflanzen und -tiere verursacht. In den nördlichen Appalachen Nordamerikas wird es nicht nur in den mittleren Höhenlagen wärmer, sondern auch der Ökoton zwischen nördlichen Hartholzwäldern und Bergnadelwäldern verschiebt sich. Daher könnte sich auch die Verbreitung von Arten, welche durch Klima oder Habitat entlang des Gebirgshöhengradienten Beschränkungen unterliegen, verändern. Zwischen 1993 und 2003 untersuchten wir Vögel entlang vergleichbarer Höhengradienten in den White Mountains in New Hampshire, USA, und verwendeten gemischte Modelle zur Schätzung der Höhenänderungsrate, um die Hypothese zu überprüfen, dass Vögel, die auf nördliche Hartholzwälder und Bergwälder angewiesen sind, sich gemäß den Vorhersagen zum Klimawandel hangaufwärts verlagern. Entsprechend den Vorhersagen verschob sich die obere Höhengrenze bei neun von 16 Tieflandarten im Laufe des Untersuchungszeitraumes im Schnitt um 99xa0m hangaufwärts. Anders als erwartet wiesen neun von elf Hochgebirgsarten niedrigere Höhengrenzen auf, die sich im Schnitt um 19xa0m hangabwärts verschoben hatten. Die entgegen gerichtete Höhenverschiebung zweier distinkter und benachbarter Vogelgesellschaften ist unseres Wissens nach beispiellos und betont, wie wichtig es ist, bei der Annahme gängiger Erwartungen bezüglich der Reaktion einer Art auf den Klimawandel Vorsicht walten zu lassen.

Early‐successional forest ecosystems: far from “forgotten”

Figure 1. Annual increase in number of references (416 altogether) resulting from a Web of Science search, conducted on 16 Mar 2011, for “(early AND succession AND conservation) OR Topic = (early AND seral AND conservation) OR Topic = (early AND succession AND ecosystem)”. world. We suggested planning for “off world” colonization as a last resort and as a precautionary response to an unstoppable redesign of the Earth. Holl and Loik argue that the large monetary sums needed for such colonization could be better spent directly on solving environmental problems here on Earth. It’s hard to argue with that sentiment in the short term. A major increase in resources directed toward goals such as K–12 education and empowering women globally would be of great value, both environmentally and economically. Yet, when we proposed the drastic step of considering space colonization, we were musing about the long term – because we believe that the deployment and extent of novel technologies will happen so fast, and may arrive with such intensity, that people may not have time to respond adequately. The increase in technological “progress” in the 21st century has been estimated to be of the same order of magnitude as that of the last 20 000 years (at today’s rate of technological change; Kurzweil 2003). Under this scenario of technological transformation, our suggestion of a “couple of centuries” for deployment of humans to space might be too long. The bulk of our editorial focused on the world today and in the near future. That’s where we’d like the focus to remain, because no one has the remotest idea of what the continued emergence of the neoenvironment will mean for us, for societies, and for the rest of life on Earth. However, it’s time we also started thinking about the distant future, which really may not be so far away. Peter Haff and Rob Jackson Duke University, Durham, NC (jackson@duke.edu)

An Evaluation of the Contribution of Cultivated Allspice (Pimenta Dioca

Tropical deforestation has emerged as one of the most important conservation challenges of our time, both because of the high species diversity and rates of endemism of tropical forests, and because of the rapid rate at which this process is proceeding. Recent studies indicate that areas of low-intensity agroforestry have similar levels of vertebrate diversity as some primary habitats, leading some researchers and conservationists to conclude that this type of commodity production could contribute to the conservation of biodiversity. We compared the composition of bird, mammal and herpetofaunal communities in primary forest, secondary forest, and pasture—and within the allspice productive systems that have replaced pasture. We found that mammal species richness was higher in primary forest than all other habitats; however for resident and migrant birds, amphibians and reptiles, species richness was similar between primary forest and the other habitats. Despite similarities in overall numbers of species, there were numerous species that were encountered only in primary habitats. We conclude that the cultivation of allspice in a mixed productive system can offset some of the losses to biodiversity; however it should be complemented by the establishment and maintenance of protected areas to accommodate populations of primary forest specialists that are unable to persist in altered habitats.

Measuring and Managing the Environmental Cost of Coffee Production in Latin America

Coffee is a major international commodity, and because of this, coffee production has the potential for considerable global impacts on the environment. These impacts can include the consumption of energy, water, land and the loss of native forest. Here we quantify these costs using Costa Rica as a case study, and describe an initiative undertaken at the Montes de Oro Cooperative in which these impacts are reduced substantially through the development and application of alternative technologies. We show how these processes reduce the consumption of resources, and also reduce economic costs to the farmer, thus providing a market-based incentive for conservation. The initiatives undertaken at Montes de Oro can provide a model for the future, for reducing the environmental costs of coffee production, while simultaneously improving the economic conditions of the people in coffee producing regions.

Recent sightings of Kirtland's Warblers on San Salvador Island, The Bahamas

Abstract Here we present recent accounts of Kirtlands Warblers (Setophaga kirtlandii) captured and observed on San Salvador Island, The Bahamas, in 2012 and 2013. We conducted mist-netting and passive surveys in a variety of habitats on the island from January–March 2012 and December 2012–March 2013. We captured four warblers and sighted at least six other individuals, including two color-banded birds originally banded near Mack Lake, Michigan, USA. Warblers were primarily captured or observed in coastal scrub and inland low coppice habitats where vegetation height is <4 m, has a scrub/shrub appearance, and openings because of disturbance. These habitats are similar to habitats preferred by Kirtlands Warblers on other Bahamian islands, and also have fruiting plants the warblers prefer such as Erithalis fruticosa, and Lantana involucrata. To our knowledge, these are the first confirmed cases of observed Kirtlands Warblers on the island in over 46 years.