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David I. King - One of the best experts on this subject based on the ideXlab platform.

  • Measuring the effectiveness of conservation programs for shrubland birds
    Global Ecology and Conservation, 2015
    Co-Authors: Scott Schlossberg, David I. King
    Abstract:

    Abstract Disturbance-dependent habitats such as grasslands and Shrublands are declining in many regions. To mitigate these declines, government agencies are using anthropogenic disturbances like logging and mowing to mimic natural ones. Because these programs can be costly or controversial, measuring their effectiveness is important. Here, we evaluate the conservation effectiveness of shrubland management for 15 bird species in Massachusetts, USA. Because Shrublands are constantly changing in extent and location, we suggest that the key measure of conservation effectiveness should be how managed areas contribute to habitat availability. We used remotely-sensed data to assess the total area of Shrublands in Massachusetts and consulted managers and a timber-harvest database to determine contributions of management by government agencies and non-governmental conservation organizations. We calculated species-specific habitat availability based on the habitat relationships of individual bird species. The area of potential habitat for shrubland birds in Massachusetts averaged 35,000 ± SD of 11,300 ha. Of this total, an average of 20% ± 15% exists because of management by government and NGOs. Management was most important for birds that nest primarily in uplands and avoid wetlands. We conclude that active management by government agencies and NGOs provides a substantial proportion of shrubland habitat in Massachusetts. With habitat on private property being lost to development or succession, active management will be even more important in the future.

  • Effects of low-density housing development on shrubland birds in western Massachusetts
    Landscape and Urban Planning, 2011
    Co-Authors: Scott Schlossberg, David I. King, Richard B. Chandler
    Abstract:

    Housing development in rural areas is the fastest-growing type of land use in the U.S. For birds, development near natural habitats is a problem because it can reduce abundances and nesting success and increase brood parasitism by brown-headed cowbirds (Molothrus ater). In southern New England, populations of shrubland birds are declining rapidly while exurban development is widespread and increasing. We studied effects of landscape-scale low-density housing development on abundance and nesting success of birds in western Massachusetts Shrublands. Study sites included beaver wetlands, utility rights-of-way managed as Shrublands, regenerating clearcuts, and mechanically treated old fields. Of 14 focal bird species, four increased with development within 1 km of study sites whereas white-throated sparrow (Zonotrichia albicollis) decreased. Abundances of avian nest predators increased slightly with development, and abundances of brown-headed cowbirds decreased with development. Prairie warblers (Dendroica discolor) had lower nest success in more developed areas, but for seven bird other species and the community as a whole, nest success did not change with development in the surrounding landscape. Brood parasitism by brown-headed cowbirds was higher on sites with more development. Overall, only white-throated sparrow and prairie warbler showed negative impacts of development, but both of these species are declining rapidly in New England. Housing development in the surrounding landscape should be a consideration in management of these species. For other shrubland birds, however, low-density housing development at the landscape scale appears to have more neutral or even positive effects.

  • An evaluation of powerline rights-of-way as habitat for early-successional shrubland birds
    Wildlife Society Bulletin, 2010
    Co-Authors: David I. King, Bruce E. Byers
    Abstract:

    Recent population declines among bird species that breed in early-successional shrubland habitats in the eastern United States have been associated with declines in habitat availability. Forest succession has eliminated Shrublands in many locations, but powerline rights-of-way constitute a potential reservoir of shrubland habitat for birds. We studied 2 populations of an early-successional shrubland bird, the chestnut-sided warbler (Dendroica pensylvanica), in powerline rights-of-way in western Massachusetts over five breeding seasons to evaluate the potential conservation value of these habitats. Our goals were to l) measure reproductive success and adult survival of birds nesting in powerline rights-of-way, 2) test for edge-related increases in nest predation that might compromise the health of bird populations in powerline rights-of-way, and 3) evaluate whether reproductive success and adult survival rates of birds nesting in powerline rights-of-way were sufficient to maintain these populations. Our results indicated that nesting and fledging success in these populations were high, but nest success was marginally lower (P=0.09) near edges in 1 of 2 years for which distances from nests to edge were measured. Also, reproductive success and adult survival were sufficient at both sites to balance losses from mortality, suggesting that powerline rights-of-way can support populations of early-successional shrubland birds.

Tamar Dayan - One of the best experts on this subject based on the ideXlab platform.

  • Increased songbird nest depredation due to Aleppo pine (Pinus halepensis) encroachment in Mediterranean shrubland.
    BMC Ecology, 2019
    Co-Authors: Asaf Ben-david, Ido Izhaki, Roni Efronny, Roi Maor, Hila Shamon, Tamar Dayan
    Abstract:

    In recent decades, a decrease of passerine densities was documented in Mediterranean Shrublands. At the same time, a widespread encroachment of Aleppo pines (Pinus halepensis) to Mediterranean shrubland occurred. Such changes in vegetation structure may affect passerine predator assemblage and densities, and in turn impact passerine densities. Depredation during the nesting season is an important factor to influence passerine population size. Understanding the effects of changes in vegetation structure (pine encroachment) on passerine nesting success is the main objective of this study. We do so by assessing the effects of Aleppo pine encroachment on Sardinian warbler (Sylvia melanocephala) nest depredation in Mediterranean Shrublands. We examined direct and indirect predation pressures through a gradients of pine density, using four methods: (1) placing dummy nests; (2) acoustic monitoring of mobbing events; (3) direct observations on nest predation using cameras; and (4) observation of Eurasian jay (Garrulus glandarius) behaviour as indirect evidence of predation risk. We found that Aleppo pine encroachment to Mediterranean Shrublands increased nest predation by Eurasian jays. Nest predation was highest in mixed shrubland and pines. These areas are suitable for warblers but had high occurrence rate of Eurasian jays. Encroaching pines directly increase activity of Eurasian jays in shrubland habitats, which reduced the nesting success of Sardinian warblers. These findings are supported by multiple methodologies, illustrating different predation pressures along a gradient of pine densities in natural Shrublands. Management of Aleppo pine seedlings and removal of unwanted trees in natural shrubland might mitigate arrival and expansion of predators and decrease the predation pressure on passerine nests.

  • Increased songbird nest depredation due to Aleppo pine (Pinus halepensis) encroachment in Mediterranean shrubland
    2019
    Co-Authors: Asaf Ben-david, Ido Izhaki, Roni Efronny, Roi Maor, Hila Shamon, Tamar Dayan
    Abstract:

    Abstract Background In recent decades, a decrease of passerine densities was documented in Mediterranean Shrublands. At the same time, a widespread encroachment of Aleppo pines ( Pinus halepensis ) to Mediterranean shrubland occurred. Such changes in vegetation structure may affect passerine predator assemblage and densities, and in turn impact passerine densities. Depredation during the nesting season is an important factor to influence passerine population size. Understanding the effects of changes in vegetation structure (pine encroachment) on passerine nesting success is the main objective of this study. We do so by assessing the effects of Aleppo pine encroachment on Sardinian warbler ( Sylvia melanocephala ) nest depredation in Mediterranean Shrublands. We examined direct and indirect predation pressures through a gradients of pine density, using four methods: (1) placing dummy nests; (2) acoustic monitoring of mobbing events; (3) direct observations on nest predation using cameras; and (4) observation of Eurasian jay ( Garrulus glandarius ) behaviour as indirect evidence of predation risk. Results We found that Aleppo pine encroachment to Mediterranean Shrublands increased nest predation by Eurasian jays. Nest predation was highest in mixed shrubland and pines. These areas are suitable for warblers but had high occurrence rate of Eurasian jays. Conclusions Encroaching pines directly increase activity of Eurasian jays in shrubland habitats, which reduced the nesting success of Sardinian warblers. These findings are supported by multiple methodologies, illustrating different predation pressures along a gradient of pine densities in natural Shrublands. Management of Aleppo pine seedlings and removal of unwanted trees in natural shrubland might mitigate arrival and expansion of predators and decrease the predation pressure on passerine nests.

  • Increased songbird nest depredation due to Aleppo pine (Pinus halepensis) encroachment in Mediterranean shrubland
    2019
    Co-Authors: Asaf Ben-david, Hila Shamoon, Ido Izhaki, Roni Efronny, Roi Maor, Tamar Dayan
    Abstract:

    Abstract Background In recent decades, a decrease of passerine densities was documented in Mediterranean Shrublands. At the same time, a widespread encroachment of Aleppo pines ( Pinus halepensis ) to Mediterranean shrubland occurred. Such changes in vegetation structure may affect passerine predator assemblage and densities, and in turn impact passerine densities. Depredation during the nesting season is an important factor to influence passerine population size. Understanding the effects of changes in vegetation structure (pine encroachment) on passerine nesting success is the main objective of this study. We do so by assessing the effects of Aleppo pine encroachment on Sardinian warbler ( Sylvia melanocephala ) nest depredation in Mediterranean Shrublands. Methods We examined direct and indirect predation pressures through a gradients of pine density, using four methods: (1) placing dummy nests; (2) acoustic monitoring of mobbing events; (3) direct observations on nest predation using cameras; and (4) observation of Eurasian jay ( Garrulus glandarius ) behaviour as indirect evidence of predation risk. Results We found that Aleppo pine encroachment to Mediterranean Shrublands increased nest predation by Eurasian jays. Nest predation was highest in mixed shrubland and pines. These areas are suitable for warblers but had high occurrence rate of Eurasian jays. Conclusions Encroaching pines directly increase activity of Eurasian jays in shrubland habitats, which reduced the nesting success of Sardinian warblers. These findings are supported by multiple methodologies, illustrating different predation pressures along a gradient of pine densities in natural Shrublands. Management of Aleppo pine seedlings and removal of unwanted trees in natural shrubland might mitigate arrival and expansion of predators and decrease the predation pressure on passerine nests.

  • Increased songbird nest depredation due to invasive Aleppo pine (Pinus halepensis) encroachment in Mediterranean shrubland
    2019
    Co-Authors: Asaf Ben-david, Hila Shamoon, Ido Izhaki, Roni Efronny, Roi Maor, Tamar Dayan
    Abstract:

    Abstract Background In recent decates, a decrease of passerine densities was documented in Mediterenean Shrublands. At the same time, a widspread encroachment of Aleppo pines (Pinus halepensis) to Mediterranean shrubland occurred. Such changes in vegetation structure may effect passerine predator assemblage and densities, and in turn impact passerine densities. Depredation during the nesting season is an important factor to influence passerine population size. Understanding the effects of changes in vegetation structure (pine encroachment) on passerine nesting success is the main objective of this study. We do so by assesing the effects of Aleppo pine encroachment on Sardinian warbler (Sylvia melanocephala) nest depredation in Mediterranean Shrublands. Methods We examined direct and indirect predation pressures throught a gradients of pine density, using four methods: (1) placing dummy nests; (2) acoustic monitoring of mobbing events; (3) direct observations on nest predation using cameras; and (4) observation of Eurasian jay (Garrulus glandarius) behaviour as indirect evidence of predation risk. Results We found that Aleppo pine encroachment to Mediterranean Shrublands increased nest predation by Eurasian jays. Nest predation was highest in with median encroaching pine. These areas are suitable for warblers, but had high occurrence rate of Eurasian jays. Conclusions Invasive pines directly increase activity of avian predators in shrubland habitats which impacted shrubland songbird nesting success. These findings are supported by multiple methodologies, illustrating different predation pressures along a gradient of pine densities in natural Shrublands. Management of Aleppo pine seedlings and removal of unwanted trees in natural shrubland might mitigate arrival and expansion of native-invasive predators and decrease the predation pressure on passerine nests.

Javier Pereztris - One of the best experts on this subject based on the ideXlab platform.

  • habitat effects on resource tracking ability do wintering blackcaps sylvia atricapilla track fruit availability
    Ibis, 2006
    Co-Authors: Jose Luis Telleria, Javier Pereztris
    Abstract:

    If resource availability shapes population distribution, changes in resource abundance should cause parallel changes in population numbers. However, tracking ability may be disrupted by different environmental and behavioural factors that act at different spatial and temporal scales. Here we analyse the ability of wintering Blackcap Sylvia atricapilla populations to track spatio-temporal variation in fruit availability in southern Spain in two habitats (forests and Shrublands) with different population structure. Former studies had shown that forests are equally used by both adult migrant and local Blackcaps, whereas Shrublands are nearly monopolized by juvenile migrants. These differences might affect resource tracking: it should be disrupted in forests, as local birds remain over winter in their breeding territories, but not in Shrublands where similarly competitive juvenile migrants can freely track the spatial distribution of fruits. We analysed the fruit-tracking ability of Blackcap populations among sites and years in both habitat types using a habitat-matching model, which predicts spatio-temporal changes in population abundance proportional to changes in resource availability. We counted Blackcaps and fruiting shrubs (dominated by Lentiscs Pistacia lentiscus and Wild Olives Olea europaea sylvestris) during four winters in forest and shrubland patches. The abundance of fruits was always higher in Shrublands than in forests. In Shrublands, Blackcaps seemed to move freely across fruit-rich habitat patches, tracking changes in fruiting-shrub abundance among sites and years. However, such tracking was not observed in forests. This supports the view that fruit-tracking ability may be constrained by local factors, such as the social structure of populations occurring in different habitat types, which introduces spatio-temporal variation in the way fruit availability shapes the abundance distribution of these birds in their Mediterranean wintering grounds.

Marc Estiarte - One of the best experts on this subject based on the ideXlab platform.

  • synthesizing greenhouse gas fluxes across nine european peatlands and Shrublands responses to climatic and environmental changes
    Biogeosciences, 2012
    Co-Authors: Mette Sustmann Carter, Marc Estiarte, Klaus Steenberg Larsen, Bridget A Emmett, C Field, I D Leith, Magnus Lund, Ana Meijide, Robert T E Mills
    Abstract:

    Abstract. In this study, we compare annual fluxes of methane (CH4), nitrous oxide (N2O) and soil respiratory carbon dioxide (CO2) measured at nine European peatlands (n = 4) and Shrublands (n = 5). The sites range from northern Sweden to Spain, covering a span in mean annual air temperature from 0 to 16 °C, and in annual precipitation from 300 to 1300 mm yr−1. The effects of climate change, including temperature increase and prolonged drought, were tested at five shrubland sites. At one peatland site, the long-term (> 30 yr) effect of drainage was assessed, while increased nitrogen deposition was investigated at three peatland sites. The Shrublands were generally sinks for atmospheric CH4, whereas the peatlands were CH4 sources, with fluxes ranging from −519 to +6890 mg CH4-C m−2 yr−1 across the studied ecosystems. At the peatland sites, annual CH4 emission increased with mean annual air temperature, while a negative relationship was found between net CH4 uptake and the soil carbon stock at the shrubland sites. Annual N2O fluxes were generally small ranging from −14 to 42 mg N2O-N m−2 yr−1. Highest N2O emission occurred at the sites that had highest nitrate (NO3−) concentration in the soil water. Furthermore, experimentally increased NO3− deposition led to increased N2O efflux, whereas prolonged drought and long-term drainage reduced the N2O efflux. Soil CO2 emissions in control plots ranged from 310 to 732 g CO2-C m−2 yr−1. Drought and long-term drainage generally reduced the soil CO2 efflux, except at a hydric shrubland where drought tended to increase soil respiration. In terms of fractional importance of each greenhouse gas to the total numerical global warming response, the change in CO2 efflux dominated the response in all treatments (ranging 71–96%), except for NO3− addition where 89% was due to change in CH4 emissions. Thus, in European peatlands and Shrublands the effect on global warming induced by the investigated anthropogenic disturbances will be dominated by variations in soil CO2 fluxes.

  • VALUATION OF CLIMATE‐CHANGE EFFECTS ON MEDITERRANEAN Shrublands
    Ecological Applications, 2007
    Co-Authors: Pere Riera, Josep Peñuelas, Verónica Farreras, Marc Estiarte
    Abstract:

    In general, the socioeconomic analysis of natural systems does not enter into the realms of natural science. This paper, however, estimates the human-welfare effects of possible physicochemical and biological impacts of climate change on Mediterranean Shrublands over the coming 50 years. The contingent choice method was applied to elicit the trade-offs in perceived values for three climate-sensitive attributes of shrubland (plant cover, fire risk, and soil erosion) and for the costs of programs designed to mitigate changes. Soil erosion was found to be the attribute of shrubland that most concerned the population, followed by fire risk and then plant cover. An increase of 1% in the shrubland area affected by erosion was estimated to cost each person on average 2.9 euros per year in terms of lost welfare, a figure that is equivalent in terms of perceptions of social welfare to an increase of 0.24% in the shrub area burned annually and a decrease of 3.19% in the area of plant cover. These trade-off values may help ecologists, policy makers, and land managers to take social preferences into account.

  • valuation of climate change effects on mediterranean Shrublands
    Ecological Applications, 2007
    Co-Authors: Pere Riera, Josep Peñuelas, Verónica Farreras, Marc Estiarte
    Abstract:

    In general, the socioeconomic analysis of natural systems does not enter into the realms of natural science. This paper, however, estimates the human-welfare effects of possible physicochemical and biological impacts of climate change on Mediterranean Shrublands over the coming 50 years. The contingent choice method was applied to elicit the trade-offs in perceived values for three climate-sensitive attributes of shrubland (plant cover, fire risk, and soil erosion) and for the costs of programs designed to mitigate changes. Soil erosion was found to be the attribute of shrubland that most concerned the population, followed by fire risk and then plant cover. An increase of 1% in the shrubland area affected by erosion was estimated to cost each person on average 2.9 euros per year in terms of lost welfare, a figure that is equivalent in terms of perceptions of social welfare to an increase of 0.24% in the shrub area burned annually and a decrease of 3.19% in the area of plant cover. These trade-off values may help ecologists, policy makers, and land managers to take social preferences into account.

Zhou Guoying - One of the best experts on this subject based on the ideXlab platform.

  • Belowground biomass of alpine Shrublands across the northeast Tibetan Plateau
    Ecology and Evolution, 2020
    Co-Authors: Nie Xiuqing, Dong Wang, Yang Lucun, Zhou Guoying
    Abstract:

    Although belowground biomass (BGB) plays an important role in global cycling, the storage of BGB and climatic effects on it are remaining unclear. With data from 49 sites, we aimed to investigate BGB and its climatic controls in alpine Shrublands in the Tibetan Plateau. Our study showed that the BGB (both grass-layer and shrub-layer biomass) storage in the alpine Shrublands was 67.24 Tg, and the mean BGB density and Shrublands area were 1,567.38 g/m2 and 4.29 × 104 km2, respectively. Shrub layer had a larger BGB stock and accounted for 66% of total BGB this area, while only 34% was accumulated in the grass layer. BGB of the grass layer in the Tibetan Plateau Shrublands was larger than that of Tibetan alpine grasslands, indicating that shrubland ecosystem played a critical importance role in carbon cycle on the Tibetan Plateau. The BGB in the grass layer and shrub layer demonstrated different correlations with climatic factors. Specifically, the effects from mean annual temperature on shrub-layer BGB were not significant, similarly to the relationship between mean annual precipitation and grass-layer BGB. But shrub-layer BGB had a significantly positive relationship with mean annual precipitation (p 

  • belowground biomass of alpine Shrublands across the northeast tibetan plateau
    Ecology and Evolution, 2020
    Co-Authors: Nie Xiuqing, Dong Wang, Yang Lucun, Zhou Guoying
    Abstract:

    Although belowground biomass (BGB) plays an important role in global cycling, the storage of BGB and climatic effects on it are remaining unclear. With data from 49 sites, we aimed to investigate BGB and its climatic controls in alpine Shrublands in the Tibetan Plateau. Our study showed that the BGB (both grass-layer and shrub-layer biomass) storage in the alpine Shrublands was 67.24 Tg, and the mean BGB density and Shrublands area were 1,567.38 g/m2 and 4.29 × 104 km2, respectively. Shrub layer had a larger BGB stock and accounted for 66% of total BGB this area, while only 34% was accumulated in the grass layer. BGB of the grass layer in the Tibetan Plateau Shrublands was larger than that of Tibetan alpine grasslands, indicating that shrubland ecosystem played a critical importance role in carbon cycle on the Tibetan Plateau. The BGB in the grass layer and shrub layer demonstrated different correlations with climatic factors. Specifically, the effects from mean annual temperature on shrub-layer BGB were not significant, similarly to the relationship between mean annual precipitation and grass-layer BGB. But shrub-layer BGB had a significantly positive relationship with mean annual precipitation (p < .05), while grass-layer BGB showed a trend of decrease with increasing mean annual temperature (p < .05). Consequently, the actual and potential increases of BGB varied due to different increases of mean annual precipitation and temperature among different areas of the Tibetan Plateau. Therefore, in the warmer and wetter scenario, due to contrary relationships from mean annual precipitation and temperature on shrub-layer BGB and grass-layer BGB, it is necessary to conduct a long-term monitoring about dynamic changes to increase the precision of assessment of BGB carbon sequestration in the Tibetan Plateau alpine Shrublands.