scholarly journals Afrotropical montane birds experience upslope shifts and range contractions along a fragmented elevational gradient in response to global warming

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248712
Author(s):  
Montague H. C. Neate-Clegg ◽  
Simon N. Stuart ◽  
Devolent Mtui ◽  
Çağan H. Şekercioğlu ◽  
William D. Newmark
Keyword(s):  
Global Warming ◽  
Bird Species ◽  
Bird Community ◽  
Elevational Gradient ◽  
Range Limits ◽  
Forest Fragments ◽  
Local Climate ◽  
Elevational Range ◽  
Changes Over Time ◽  
Over Time

Global warming is predicted to result in upslope shifts in the elevational ranges of bird species in montane habitats. Yet few studies have examined changes over time in the elevational distribution of species along fragmented gradients in response to global warming. Here, we report on a resurvey of an understory bird community in the Usambara Mountains in Tanzania, along a forested elevational gradient that has been fragmented over the last 200 years. In 2019, we resurveyed seven sites, ranging in elevation from 360 m to 2110 m, that were originally surveyed between 1979 and 1981. We calculated differences in mean elevation and lower and upper range limits for 29 species between the two time periods and corrected for possible differences in elevation due to chance. Over four decades, we documented a significant mean upslope shift across species of 93 m. This shift was smaller than the 125 m expected shift due to local climate warming. Of the 29 focal species, 19 shifted upslope, eight downslope, and two remained unchanged. Mean upslope shifts in species were driven largely by contracting lower range limits which moved significantly upslope on average across species by 183 m, while upper range limits shifted non-significantly upslope by 72 m, leading to a mean range contraction of 114 m across species. Community composition of understory bird species also shifted over time, with current communities resembling communities found historically at lower elevations. Past forest fragmentation in combination with the limited gap-crossing ability of many tropical understory bird species are very likely important contributory factors to the observed asymmetrical shifts in lower and upper elevational range limits. Re-establishing forested linkages among the largest and closest forest fragments in the Eastern Arc Mountains are critical to permitting species to shift upslope and to reduce further elevational range contractions over time.

scholarly journals Behavior influences range limits and patterns of coexistence across an elevational gradient in tropical bird diversity

2019 ◽  
Author(s):  
Benjamin G Freeman ◽  
Joseph A Tobias ◽  
Dolph Schluter
Keyword(s):  
Interference Competition ◽  
Bird Species ◽  
Elevational Gradient ◽  
Range Limits ◽  
Bird Diversity ◽  
Basic Question ◽  
Evolutionary Relatedness ◽  
Range Overlap ◽  
Elevational Range ◽  
Close Relatives

AbstractDoes competition influence patterns of coexistence between closely related taxa? Here we address this basic question in ecology by analyzing patterns of range overlap between related bird species (“sister pairs”) distributed along a Neotropical elevational gradient. We explicitly contrast the behavioral dimension of interspecific competition (interference competition) with similarity in resource acquisition traits (exploitative competition). We find that behavioral interactions are generally important in setting elevational range limits and preventing coexistence of closely related species. Specifically, close relatives that defend year-round territories tend to live in non-overlapping elevational distributions, while close relatives that do not defend territories tend to broadly overlap in distribution. In contrast, neither similarity in beak morphology nor evolutionary relatedness was associated with patterns of range limitation. Our main result is that interference competition can be an important driver of species ranges at the scale of entire diverse assemblages. Consequently, we suggest that behavioral dimensions of the niche should be more broadly incorporated in macroecological studies.

scholarly journals Evidence of change in a low-elevation forest bird community of Hawai'i since 1979

2003 ◽  
Vol 13 (3) ◽  
pp. 175-187 ◽  
Author(s):  
Michelle H. Reynolds ◽  
Richard J. Camp ◽  
Bonnie M. B. Nielson ◽  
James D. Jacobi
Keyword(s):  
Native Species ◽  
Bird Species ◽  
Bird Community ◽  
Natural Area ◽  
Present Evidence ◽  
Forest Bird ◽  
Bird Survey ◽  
Elevational Range ◽  
Abundance And Distribution ◽  
Avian Disease

We evaluated the abundance and distribution of low-elevation forest birds on windward Hawai'i Island during August 1993-February 1994, and present evidence of changes in the species composition of the forest bird community since 1979. Endemic Hawaiian birds occurred in native-dominated forests as low as 120 m elevation. Non-native species were detected at all survey locations. We observed non-native Saffron Finch Sicalis flaveola, previously unrecorded in Puna. Variable circular plot surveys of Kahauale'a Natural Area Reserve indicated the disappearance of two native species ('I'iwi Vestiaria coccinea and 'O'u Psittitostra psittacea), and two non-native additions (Red-billed Leiothrix Leiothrix lutea and Kalij Pheasant Lophura leucomelana) to the study area since the Hawai'i Forest Bird Survey conducted in 1979. We present evidence that native 'Elepaio Chasiempsis sandwichensis has experienced a decrease in population density and an elevational range contraction since 1979. Surveys indicate Puna's forest bird community has had increasing aliens and declining native species since 1979. The persistence of some native bird species within the range of avian disease vectors such as Culex quinquefasciatus in forests below 1,000 m elevation presents an important enigma that requires additional study.

scholarly journals Changes in the structure and composition of the ‘Mexical’ scrubland bee community along an elevational gradient

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254072
Author(s):  
Sergio Osorio-Canadas ◽  
Noé Flores-Hernández ◽  
Tania Sánchez-Ortiz ◽  
Alfonso Valiente-Banuet
Keyword(s):  
Global Warming ◽  
Life Story ◽  
Extinction Risk ◽  
Elevation Gradient ◽  
Elevational Gradient ◽  
Negative Consequences ◽  
Flower Density ◽  
Bee Community ◽  
Elevational Range ◽  
Bee Abundance

‘Mexical’ scrubland is a sclerophyllous evergreen Mediterranean-like vegetation occurring in the leeward slopes of the main Mexican mountain ranges, under tropical climate. This biome occupies an elevational range approximately from 1900 to 2600 meters above sea level, which frequently is the upper-most part of the mountains range. This puts it at risk of extinction in a scenario of global warming in which an upward retraction of this type of vegetation is expected. The Mexical remains one of the least studied ecosystems in Mexico. For instance, nothing is known about pollinator fauna of this vegetation. Our main objective is to make a first insight into the taxonomic identity of the bee fauna that inhabits this biome, and to study how it is distributed along the elevational gradient that it occupies. Our results highlight that elevation gradient negatively affects bee species richness and that this relationship is strongly mediated by temperature. Bee abundance had no significant pattern along elevational gradient, but shows a significant relationship with flower density. Interestingly, and contrary to previous works, we obtained a different pattern for bee richness and bee abundance. Bee community composition changed strongly along elevation gradient, mainly in relation to temperature and flower density. In a global warming scenario, as temperatures increases, species with cold preferences, occupying the highest part of the elevation gradient, are likely to suffer negative consequences (even extinction risk), if they are not flexible enough to adjust their physiology and/or some life-story traits to warmer conditions. Species occupying mid and lower elevations are likely to extend their range of elevational distribution towards higher ranges. This will foreseeably cause a new composition of species and a new scenario of interactions, the adjustment of which still leaves many unknowns to solve.

scholarly journals Diversity of Bird Communities in Tea (Camellia sinensis) Plantations in Fujian Province, South-Eastern China

Diversity ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 457
Author(s):  
Titus S. Imboma ◽  
Marco Ferrante ◽  
Min-sheng You ◽  
Shijun You ◽  
Gábor L. Lövei
Keyword(s):  
Eastern China ◽  
Bird Species ◽  
Bird Community ◽  
Bird Communities ◽  
Forest Fragments ◽  
Species Accumulation Curves ◽  
Fujian Province ◽  
Mountain Areas ◽  
South Eastern ◽  
Tea Plantations

Habitat conversion in mountain areas threatens their biodiversity. The effect on biodiversity of creating a mountain landscape with a network of forest fragments and a cultivated habitat matrix is poorly documented in China. Bird communities in forest fragments and tea plantations were censused by field observations in two years (2018–2019) in three tea-growing locations, Anxi, Beifeng, and Wuyishan in Fujian Province, south-eastern China. Out of a potential pool of 247 forest-associated bird species, we detected the presence of 82, mostly resident species, 32–47 of those regularly visiting tea plantations. Species-accumulation curves indicated the near-completeness of the census. The Rényi diversity profiles indicated a more diverse community in forest fragments than nearby tea plantations at Anxi and Beifeng, but the tea plantations at Wuyishan supported a more diverse bird community than the forest. Avian communities in tea plantations were a significantly nested subset of the forest communities. Tea plantations can provide resources for forest-associated birds, but the effectiveness of preserving avian diversity depends on natural forest fragments and can be enhanced by landscape-scale management, when the biocontrol potential of birds can also be enhanced.

scholarly journals Bird community structure as a function of habitat heterogeneity: A case of Mardi Himal, Central Nepal

2020 ◽  
Vol 22 (1) ◽  
Author(s):  
Naresh Pandey ◽  
Laxman Khanal ◽  
Neeti Chapagain ◽  
K. Deepak Singh ◽  
Bishnu Prasad Bhattarai ◽  
...  
Keyword(s):  
Community Structure ◽  
Habitat Heterogeneity ◽  
Bird Species ◽  
Bird Community ◽  
Elevational Gradient ◽  
Feeding Guilds ◽  
Habitat Types ◽  
Conservation Area ◽  
Point Count ◽  
Central Nepal

Abstract. Pandey N, Khanal L, Chapagain N, Singh KD, Bhattarai BP, Chalise MK. 2021. Bird community structure as a function of habitat heterogeneity: A case of Mardi Himal, Central Nepal. Biodiversitas 22: 262-271. Community structure of birds at different habitat types is underexplored in the montane environment of the central Himalaya. Therefore, this study explored bird community structure in different habitat types in Mardi Himal of the Annapurna Conservation Area, central Nepal, and tested association of different feeding guilds with the habitats. Data on the avian richness and abundance were collected in the winter and the summer of 2019 by point count method along the elevational gradient in every 100 m rise and analyzed using ordination methods. A total of 673 individuals of 112 bird species from 35 families under 13 orders were recorded. Among the observed orders and families, the order Passeriformes (77 species) and family Muscicapidae (16 species) were the most dominant. A linear species accumulation curve was obtained in both seasons. Species richness and abundance were found higher at forest edges of mid-elevations and insectivores were the most abundant birds. Frugivorous and carnivorous birds showed no specific association with habitat types, whereas, insectivores and omnivores were more abundant in pastureland and forest, respectively. Our results revealed that the community composition of birds varies with the habitat types and their feeding specialization is one of the major determinants.

scholarly journals Fifteen years in a global warming hotspot: changes in subtidal mobile invertebrate communities

2020 ◽  
Vol 656 ◽  
pp. 227-238 ◽  
Author(s):  
YR Mulders ◽  
T Wernberg
Keyword(s):  
Global Warming ◽  
Latitudinal Gradient ◽  
Cumulative Effect ◽  
Lower Latitude ◽  
Size Distributions ◽  
Invertebrate Communities ◽  
Cool Temperate ◽  
Changes Over Time ◽  
Warm Temperate ◽  
Over Time

Temperate subtidal reefs are increasingly exposed to gradual warming and short periods of high temperatures (marine heatwaves; MHWs). These pressures can directly and indirectly affect the mobile invertebrate communities on these reefs. We investigate changes in mobile invertebrate communities from benthic surveys 15 yr apart (1999-2001 vs 2016-2019), spanning a 4° latitudinal gradient in Western Australia (30-34°S), expecting the biggest changes to the communities in the lower latitudes, where the cumulative effect of MHWs and warming is largest. The urchins Centrostephanus tenuispinus (warm temperate affinity) and Phyllacanthus irregularis (cool temperate affinity) showed trends toward opposite responses over time; while P. irregularis densities declined (non-significantly at all sites), C. tenuispinus densities increased (significantly at one of 3 sites). The magnitude of the responses appeared to decrease with increasing latitude, with C. tenuispinus recorded in significantly higher densities only at the lowest latitude location. Neither the densities, nor change in density over time of cool temperate gastropod Lunella torquatus and urchin Heliocidaris erythrogramma reflected a latitudinal gradient, suggesting other localized factors play a larger role in determining abundances of these species. However, size distributions of L. torquatus populations at the lower latitude locations were clearly impacted by the 2011 MHW, while those at higher latitudes remained relatively consistent. Overall, the biggest changes over time were seen at the warm edge of the temperate ecosystem. As temperatures continue to rise, the magnitude of these changes is not only expected to increase, but also to occur at higher latitudes.

Comparison of two devices for measuring exercise transcutaneous oxygen pressures in patients with claudication

VASA ◽  
2015 ◽  
Vol 44 (5) ◽  
pp. 355-362 ◽  
Author(s):  
Marie Urban ◽  
Alban Fouasson-Chailloux ◽  
Isabelle Signolet ◽  
Christophe Colas Ribas ◽  
Mathieu Feuilloy ◽  
...  
Keyword(s):  
Oxygen Pressure ◽  
Optical Sensors ◽  
Chemical Sensors ◽  
Transcutaneous Oxygen ◽  
Starting Values ◽  
Two Systems ◽  
Transcutaneous Oxygen Pressure ◽  
New Sensors ◽  
Changes Over Time ◽  
Over Time

Abstract. Summary: Background: We aimed at estimating the agreement between the Medicap® (photo-optical) and Radiometer® (electro-chemical) sensors during exercise transcutaneous oxygen pressure (tcpO2) tests. Our hypothesis was that although absolute starting values (tcpO2rest: mean over 2 minutes) might be different, tcpO2-changes over time and the minimal value of the decrease from rest of oxygen pressure (DROPmin) results at exercise shall be concordant between the two systems. Patients and methods: Forty seven patients with arterial claudication (65 + / - 7 years) performed a treadmill test with 5 probes each of the electro-chemical and photo-optical devices simultaneously, one of each system on the chest, on each buttock and on each calf. Results: Seventeen Medicap® probes disconnected during the tests. tcpO2rest and DROPmin values were higher with Medicap® than with Radiometer®, by 13.7 + / - 17.1 mm Hg and 3.4 + / - 11.7 mm Hg, respectively. Despite the differences in absolute starting values, changes over time were similar between the two systems. The concordance between the two systems was approximately 70 % for classification of test results from DROPmin. Conclusions: Photo-optical sensors are promising alternatives to electro-chemical sensors for exercise oximetry, provided that miniaturisation and weight reduction of the new sensors are possible.

Neuropsychological Symptoms in Posttraumatic Stress Disorder and Changes Over Time

2007 ◽  
Author(s):  
Miranda Olff ◽  
Mirjam Nijdam ◽  
Kristin Samuelson ◽  
Julia Golier ◽  
Mariel Meewisse ◽  
...  
Keyword(s):  
Posttraumatic Stress Disorder ◽  
Posttraumatic Stress ◽  
Stress Disorder ◽  
Neuropsychological Symptoms ◽  
Changes Over Time ◽  
Over Time

Changes Over Time in Adaptive Behavior Functioning of Twice-Exceptional Children

2010 ◽  
Author(s):  
Rebecca D. Stinson ◽  
Zachary Sussman ◽  
Megan Foley Nicpon ◽  
Allison L. Allmon ◽  
Courtney Cornick ◽  
...  
Keyword(s):  
Adaptive Behavior ◽  
Exceptional Children ◽  
Twice Exceptional ◽  
Changes Over Time ◽  
Over Time
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