1,154 research outputs found
Where are the tropical plants? A call for better inclusion of tropical plants in studies investigating and predicting the effects of climate change
Tropical plant species are systematically underrepresented in large-scale analyses or synthesis looking at the potential effects of global climate change. The reason being that we simply don’t know enough about the distributions and ecologies of most tropical plant species to predict their fate under climate change. This gaping hole in our knowledge is extremely worrisome given the high diversity of tropical plants, the crucial roles that they play in supporting global diversity and ecosystem function, and the elevated threats that climate change may pose to tropical species in general. </p
Four Decades of Andean Timberline Migration and Implications for Biodiversity Loss with Climate Change
Rapid 21st-century climate change may lead to large population decreases and extinction in tropical montane cloud forest species in the Andes. While prior research has focused on species migrations per se, ecotones may respond to different environmental factors than species. Even if species can migrate in response to climate change, if ecotones do not they can function as hard barriers to species migrations, making ecotone migrations central to understanding species persistence under scenarios of climate change. We examined a 42-year span of aerial photographs and high resolution satellite imagery to calculate migration rates of timberline–the grassland-forest ecotone–inside and outside of protected areas in the high Peruvian Andes. We found that timberline in protected areas was more likely to migrate upward in elevation than in areas with frequent cattle grazing and fire. However, rates in both protected (0.24 m yr-1) and unprotected (0.05 m yr-1) areas are only 0.5–2.3% of the rates needed to stay in equilibrium with projected climate by 2100. These ecotone migration rates are 12.5 to 110 times slower than the observed species migration rates within the same forest, suggesting a barrier to migration for mid- and high-elevation species. We anticipate that the ecotone will be a hard barrier to migration under future climate change, leading to drastic population and biodiversity losses in the region unless intensive management steps are taken
Centuries-old logging legacy on spatial and temporal patterns in understory herb communities
a b s t r a c t Understory herb communities in the Southern Appalachians are among the highest biodiversity plant communities in North America. In the mid-1990s, a debate began over whether understory herb communities recover to their pre-disturbance states following logging. Studies showing reduced herb-layer diversity in previously logged forests were criticized for not accounting for intersite environmental heterogeneity. More recent studies have addressed environmental heterogeneity, but have neglected long-term recovery by using "mature forests" as young as 80 years old as the benchmark for diversity comparison, even though old growth stands have disturbance return intervals exceeding 500 years. Here we address concerns clouding previous studies of high-diversity Appalachian herb communities and investigate their long-term recovery by comparing paired sites of old growth forest and forest logged 100-150 years ago. We found that species richness and individual abundance is greater in old growth forests than mature forests and that species composition differed significantly between the two. Turnover in species among old growth and mature forests accounted for 11% of the total species richness and was significantly greater than expected. Species turnover at intermediate (5-50 m) and landscape-scales (>10 km) contributed the most towards total species richness. Herb communities in rich cove forests have successional trajectories that exceed 150 years, with important community changes still occurring long after the forest returns to what has been previously termed a "mature" state. To conserve the diverse herb layer, we conclude that mature forest stands are too young to serve as baselines for recovery, landscapescale preservation of multiple forest stands is needed to maximize species richness, and maintaining 100-150-year logging rotations will likely lead to loss of biodiversity
An annotated checklist of trees and relatives in tropical montane forests from southeast Peru: the importance of continue collecting
Los Andes están considerados como los puntos calientes más diversos de los trópicos, dentro de estos se encuentra el Parque Nacional del Manu, cuyas complejas condiciones climáticas y fisiográficas albergan una mega-diversidad y endemismo. En el presente trabajo se presenta una lista anotada de especies arbóreas y afines a lo largo de un gradiente de elevación desde los bosques submontanos a 800 m hasta la línea de bosque a 3625 m en la Reserva de Biosfera del Manu. En base a una red de 21 parcelas permanentes de una hectárea y exploraciones botánicas se sistematiza la información florística por rangos de elevación, distribución geográfica y endemismo. Estos resultados preliminares se traducen en 1108 especies de las cuales el 39.7% son morfoespecies, el 43% de las especies determinadas son registros nuevos para la región del Cusco, 15 especies son nuevos registros para la flora peruana, 40 especies son endémicas para Perú y 30 son potenciales especies nuevas para la ciencia. Adicionalmente, se resalta la expansión del rango altitudinal para el 45.2% de las especies determinadas (302 especies). Estos resultados son una muestra de la alta diversidad arbórea y afines en estos ecosistemas montañosos registrados en tan solo ~20 km de distancia geográfica, además muestra lo escasamente colectados y poco estudiados que se encuentran. Mas colecciones botánicas son necesarias - estos estudios básicos de florística son imperativos para un mejor entendimiento de la distribución de especies y la función del ecosistemas, además ayudará a responder una de las grandes preguntas en la ecología global moderna, ¿Cómo responderán los bosques tropicales al cambio climático global?The tropical Andes and adjacent Amazon are Earth’s highest biodiversity hotspot. Manu National Park in southeastern Peru encompasses an entire watershed, ranging from Andean highlands to Amazonian lowlands, and is a megadiverse landscape on the Andes to Amazon transition. Here we present an annotated checklist of trees and related species is along an elevation gradient in the Manu Biosphere Reserve that runs from sub-montane forests at 800 m elevation up to the tree line at 3625 m. Based on a network of 21 1-hectare permanent tree plots and botanical explorations, the floristic information is systematized by elevation ranges, geographical distribution and endemism. These preliminary results show 1108 species. Of these, 43% are new records for the region of Cusco, 15 species are new records for the Peruvian flora, 40 species are endemics for Peru, and 30 are potential new species for science. Another 39.7% are identified to genus or family level and remain morphospecies. Additionally, we show altitudinal range expansion for 45.2% of identified species (302 species). These results were found in a transect of plots spanning only 20 km of geographic distance, and are a sample of the high tree diversity in these mountainous ecosystems. The data show how poorly collected and understudied these ecosystems are. Basic floristic studies and collections are imperative for a better understanding of species distribution and function of ecosystems, and the basic biodiversity of the tropical Andes. They will also help to answer a major, unresolved question in modern global ecology of how tropical forests will respond to global climate change
Microbes do not follow the elevational diversity patterns of plants and animals
The elevational gradient in plant and animal diversity is one of the most widely documented patterns in ecology and, although no consensus explanation exists, many hypotheses have been proposed over the past century to explain these patterns. Historically, research on elevational diversity gradients has focused almost exclusively on plant and animal taxa. As a result, we do not know whether microbes exhibit elevational gradients in diversity that parallel those observed for macroscopic taxa. This represents a key knowledge gap in ecology, especially given the ubiquity, abundance, and functional importance of microbes. Here we show that, across a montane elevational gradient in eastern Peru, bacteria living in three distinct habitats (organic soil, mineral soil, and leaf surfaces) exhibit no significant elevational gradient in diversity (r2 0.1 in all cases), in direct contrast to the significant diversity changes observed for plant and animal taxa across the same montane gradient (r2 > 0.75, P < 0.001 in all cases). This finding suggests that the biogeographical patterns exhibited by bacteria are fundamentally different from those of plants and animals, highlighting the need for the development of more inclusive concepts and theories in biogeography to explain these disparities
Influence of inflammatory polyarthritis on quantitative heel ultrasound measurements.
BACKGROUND: There are few data concerning the impact of inflammatory polyarthritis (IP) on quantitative heel ultrasound (QUS) measurements. The aims of this analysis were i) to determine the influence of IP on QUS measurements at the heel and, ii) among those with IP to determine the influence of disease related factors on these measurements. METHODS: Men and women aged 16 years and over with recent onset IP were recruited to the Norfolk Arthritis Register (NOAR). Individuals with an onset of joint symptoms between 1989 and 1999 were included in this analysis. At the baseline visit subjects underwent a standardised interview and clinical examination with blood taken for rheumatoid factor. A population-based prospective study of chronic disease (EPIC-Norfolk) independently recruited men and women aged 40 to 79 years from the same geographic area between 1993 and 1997. At a follow up assessment between 1998 and 2000 subjects in EPIC-Norfolk were invited to have quantitative ultrasound measurements of the heel (CUBA-Clinical) performed. We compared speed of sound (SOS) and broadband ultrasound attenuation (BUA), in those subjects recruited to NOAR who had ultrasound measurements performed (as part of EPIC-Norfolk) subsequent to the onset of joint symptoms with a group of age and sex matched non-IP controls who had participated in EPIC-Norfolk. Fixed effect linear regression was used to explore the influence of IP on the heel ultrasound parameters (SOS and BUA) so the association could be quantified as the mean difference in BUA and SOS between cases and controls. In those with IP, linear regression was used to examine the association between these parameters and disease related factors. RESULTS: 139 men and women with IP and 278 controls (mean age 63.2 years) were studied. Among those with IP, mean BUA was 76.3 dB/MHz and SOS 1621.8 m/s. SOS was lower among those with IP than the controls (difference = -10.0; 95% confidence interval (CI) -17.4, -2.6) though BUA was similar (difference = -1.2; 95% CI -4.5, +2.1). The difference in SOS persisted after adjusting for body mass index and steroid use. Among those with IP, disease activity as determined by the number of swollen joints at baseline, was associated with a lower SOS. In addition SOS was lower in the subgroup that satisfied the 1987 ACR criteria. By contrast, disease duration, steroid use and HAQ score were not associated with either BUA or SOS. CONCLUSIONS: In this general population derived cohort of individuals with inflammatory polyarthritis there is evidence from ultrasound of a potentially adverse effect on the skeleton. The effect appears more marked in those with active disease.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Evolutionary heritage shapes tree distributions along an Amazon-to-Andes elevation gradient
Understanding how evolutionary constraints shape the elevational distributions of tree lineages provides valuable insight into the future of tropical montane forests under global change. With narrow elevational ranges, high taxonomic turnover, frequent habitat specialization, and exceptional levels of endemism, tropical montane forests and trees are predicted to be highly sensitive to environmental change. Using plot census data from a gradient traversing > 3,000 m in elevation on the Amazonian flank of the Peruvian Andes, we employ phylogenetic approaches to assess the influence of evolutionary heritage on distribution trends of trees at the genus‐level. We find that closely related lineages tend to occur at similar mean elevations, with sister genera pairs occurring a mean 254 m in elevation closer to each other than the mean elevational difference between non‐sister genera pairs. We also demonstrate phylogenetic clustering both above and below 1,750 m a.s.l, corresponding roughly to the cloud‐base ecotone. Belying these general trends, some lineages occur across many different elevations. However, these highly plastic lineages are not phylogenetically clustered. Overall, our findings suggest that tropical montane forests are home to unique tree lineage diversity, constrained by their evolutionary heritage and vulnerable to substantial losses under environmental changes, such as rising temperatures or an upward shift of the cloud‐base.National Science Foundation, Grant/Award Number: NSF DEB LTREB 1754647 and NSF DEB LTREB 1754664; Natural Environment Research Council, Grant/Award Number: NE/G018278/1 and NE/L002558/1; Australian Research Council, Grant/Award Number: DP17010409
climate change and biodiversity in Amazonia: a Late-Holocene perspective
Fire is an important and arguably unnatural component of many wet Amazonian and Andean forest systems. Soil charcoal has been used to infer widespread human use of landscapes prior to European Conquest. An analysis of Amazonian soil carbon records reveals that the records have distinct spatial and temporal patterns, suggesting that either fires were only set in moderately seasonal areas of Amazonia or that strongly seasonal and aseasonal areas are undersampled. Synthesizing data from 300 charcoal records, an age-frequency diagram reveals peaks of fire apparently coinciding with some periods of very strong El Niñ o activity. However, the El Niñ o record does not always provide an accurate prediction of fire timing, and a better match is found in the record of insolation minima. After the time of European contact, fires became much scarcer within Amazonia. In both the Amazonia and the Andes, modern fire pattern is strongly allied to human activity. On the flank of the Andes, forests that have never burned are being eroded by fire spreading downslope from grasslands. Species of these same forests are being forced to migrate upslope due to warming and will encounter a firm artificial fire boundary of human activity
Assessing the carbon capture potential of reforestation project
Acknowledgements We acknowledge funding through the UP-Green-LCA (NE/P019668/1) and Soils-R-GGREAT (NE/P019498/1) projects of the greenhouse gas removal (GGR) programme. The GGR programme is financed by the UK Natural Environment Research Council (NERC), Engineering and Physical Science Research Council (EPSRC), Economic and Social Science Research Council (ESRC) and the UK department for Business, Energy and Industrial Strategy (BEIS). We thank CINCIA and its funders (USAID and WWF) for their help and support during this projectPeer reviewedPublisher PD
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