Habitat fragmentation causes collapse of kelp recruitment

2020 ◽  
Vol 648 ◽  
pp. 111-123
Author(s):  
C Layton ◽  
MJ Cameron ◽  
M Tatsumi ◽  
V Shelamoff ◽  
JT Wright ◽  
...  
Keyword(s):  
Habitat Fragmentation ◽  
Patch Size ◽  
Life Stage ◽  
Extended Period ◽  
Anthropogenic Disturbances ◽  
Anthropogenic Sources ◽  
Kelp Forests ◽  
Natural Disturbances ◽  
Short Term ◽  
Turf Algae

Kelp forests in many regions are experiencing disturbance from anthropogenic sources such as ocean warming, pollution, and overgrazing. Unlike natural disturbances such as storms, anthropogenic disturbances often manifest as press perturbations that cause persistent alterations to the environment. One consequence is that some kelp forests are becoming increasingly sparse and fragmented. We manipulated patch size of the kelp Ecklonia radiata over 24 mo to simulate persistent habitat fragmentation and assessed how this influenced the demography of macro- and microscopic juvenile kelp within the patches. At the beginning of the experiment, patch formation resulted in short-term increases in E. radiata recruitment in patches <1 m2. However, recruitment collapsed in those same patches over the extended period, with no recruits observed after 15 mo. Experimental transplants of microscopic and macroscopic juvenile sporophytes into the patches failed to identify the life stage impacted by the reductions in patch size, indicating that the effects may be subtle and require extended periods to manifest, and/or that another life stage is responsible. Abiotic measurements within the patches indicated that kelp were less able to engineer the sub-canopy environment in smaller patches. In particular, reduced shading of the sub-canopy in smaller patches was associated with proliferation of sediments and turf algae, which potentially contributed to the collapse of recruitment. We demonstrate the consequences of short- and longer-term degradation of E. radiata habitats and conclude that habitat fragmentation can lead to severe disruptions to kelp demography.

scholarly journals Human encroachment into wildlife gut microbiomes

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Gloria Fackelmann ◽  
Mark A. F. Gillingham ◽  
Julian Schmid ◽  
Alexander Christoph Heni ◽  
Kerstin Wilhelm ◽  
...  
Keyword(s):  
Habitat Fragmentation ◽  
Alpha Diversity ◽  
Anthropogenic Disturbances ◽  
Vital Role ◽  
Domesticated Animals ◽  
Generalist Species ◽  
Fragmented Forest ◽  
Catch Up ◽  
Per Se ◽  
The One

AbstractIn the Anthropocene, humans, domesticated animals, wildlife, and their environments are interconnected, especially as humans advance further into wildlife habitats. Wildlife gut microbiomes play a vital role in host health. Changes to wildlife gut microbiomes due to anthropogenic disturbances, such as habitat fragmentation, can disrupt natural gut microbiota homeostasis and make animals vulnerable to infections that may become zoonotic. However, it remains unclear whether the disruption to wildlife gut microbiomes is caused by habitat fragmentation per se or the combination of habitat fragmentation with additional anthropogenic disturbances, such as contact with humans, domesticated animals, invasive species, and their pathogens. Here, we show that habitat fragmentation per se does not impact the gut microbiome of a generalist rodent species native to Central America, Tome’s spiny rat Proechimys semispinosus, but additional anthropogenic disturbances do. Indeed, compared to protected continuous and fragmented forest landscapes that are largely untouched by other human activities, the gut microbiomes of spiny rats inhabiting human-disturbed fragmented landscapes revealed a reduced alpha diversity and a shifted and more dispersed beta diversity. Their microbiomes contained more taxa associated with domesticated animals and their potential pathogens, suggesting a shift in potential metagenome functions. On the one hand, the compositional shift could indicate a degree of gut microbial adaption known as metagenomic plasticity. On the other hand, the greater variation in community structure and reduced alpha diversity may signal a decline in beneficial microbial functions and illustrate that gut adaption may not catch up with anthropogenic disturbances, even in a generalist species with large phenotypic plasticity, with potentially harmful consequences to both wildlife and human health.

Patch size but not short-term isolation influences occurrence of westslope cutthroat trout above human-made barriers

2013 ◽  
Vol 23 (4) ◽  
pp. 556-571 ◽  
Author(s):  
Douglas P. Peterson ◽  
Bruce E. Rieman ◽  
Dona L. Horan ◽  
Michael K. Young
Keyword(s):  
Patch Size ◽  
Cutthroat Trout ◽  
Westslope Cutthroat Trout ◽  
Short Term

scholarly journals Measurement report: Short-term variation in ammonia concentrations in an urban area increased by mist evaporation and emissions from a forest canopy with bird droppings

2020 ◽  
Vol 20 (20) ◽  
pp. 11941-11954
Author(s):  
Kazuo Osada
Keyword(s):  
Urban Areas ◽  
Forest Canopy ◽  
Anthropogenic Sources ◽  
Daily Maximum ◽  
Short Term ◽  
Daily Minimum ◽  
Bird Droppings ◽  
Morning Peak ◽  
Air Temperatures ◽  
Cloudy Weather

Abstract. Local meteorological conditions and natural and anthropogenic sources affect atmospheric NH3 concentrations in urban areas. To investigate potential sources and processes of NH3 variation in urban areas, hourly NH3 and NH4+ concentrations were measured during November 2017–October 2019 in Nagoya, a central Japanese megacity. Average NH3 concentrations are high in summer and low in winter. Daily minimum NH3 concentrations are linearly correlated with daily minimum air temperatures. By contrast, daily maximum NH3 concentrations increase exponentially with temperature, suggesting that different nighttime and daytime processes and air temperatures affect concentrations. Short-term increases in NH3 concentrations of two types were examined closely. Infrequent but large increases (11 parts per billion (ppb) for 2 h) occurred after mist evaporation during daytime. During 2 years of observations, only one event of this magnitude was identified in Nagoya, although evaporation of mist and fog occurs frequently after rains. Also, short-term increases occur with a large morning peak in summer. Amplitudes of diurnal variation in NH3 concentration (daily maximum minus minimum) were analyzed on days with nonwet and low wind conditions. Amplitudes were small (ca. 2 ppb) in winter, but they increased from early summer along with new leaf growth. Amplitudes peaked in summer (ca. 20 ppb) because of droppings from hundreds of crows before roosting in trees on the campus. High daily maximum NH3 concentrations were characterized by a rapid increase occurring 2–4 h after local sunrise. In summer, peak NH3 concentrations at around 08:00 local time (LT) in sunny weather were greater than in cloudy weather, suggesting that direct sunlight particularly boosts the morning peak. Daily and seasonal findings related to the morning peak imply that stomatal emission at the site causes the increase. Differences between daily amplitudes during the two summers was explained by the different input amounts of reactive nitrogen from bird droppings and rain, suggesting that bird droppings, a temporary rich source of NH3, affected the small forest canopy.

Abnormal Times

2019 ◽  
pp. 313-328
Author(s):  
Emily Gioielli
Keyword(s):  
Eastern Europe ◽  
Extended Period ◽  
State Building ◽  
First World War ◽  
World War ◽  
Short Term ◽  
The First World War ◽  
Political Factions ◽  
Military Occupations ◽  
First World

THE END of the First World War in eastern Europe could hardly be said to have inaugurated a period of peace. Marked by revolutions, counter-revolutions, renewed foreign warfare, and military occupations, the early post-armistice state-building processes were violent affairs, as political factions wrestled for dominance over their political, ethnic, and religious enemies, and armies battled for territory. This extended period of conflict and violence in the region could be described as the ‘long First World War’. The conflicts that shaped it traced their short-term roots to the preceding years of open warfare and the revolutions that occurred in the wake of the defeat of the Central Powers....

scholarly journals Did the introduction and increased prescribing of antidepressants lead to changes in long-term trends of suicide rates?

2020 ◽  
Author(s):  
Simone Amendola ◽  
Martin Plöderl ◽  
Michael P Hengartner
Keyword(s):  
General Pattern ◽  
Extended Period ◽  
Joinpoint Regression ◽  
Short Term ◽  
Term Study ◽  
Suicide Rates ◽  
Long Term Study ◽  
Prescription Rates ◽  
Long Term Trends

Abstract Background Ecological studies have explored associations between suicide rates and antidepressant prescriptions in the population, but most of them are limited as they analyzed short-term correlations that may be spurious. The aim of this long-term study was to examine whether trends in suicide rates changed in three European countries when the first antidepressants were introduced in 1960 and when prescription rates increased steeply after 1990 with the introduction of the serotonin reuptake inhibitors (SSRIs). Methods Data were extracted from the WHO Mortality Database. Suicide rates were calculated for people aged 10–89 years from 1951–2015 for Italy, 1955–2016 for Austria and 1951–2013 for Switzerland. Trends in suicide rates stratified by gender were analyzed using joinpoint regression models. Results There was a general pattern of long-term trends that was broadly consistent across all three countries. Suicide rates were stable or decreasing during the 1950s and 1960s, they rose during the 1970s, peaked in the early 1980s and thereafter they declined. There were a few notable exceptions to these general trends. In Italian men, suicide rates increased until 1997, then fell sharply until 2006 and increased again from 2006 to 2015. In women from all three countries, there was an extended period during the 2000s when suicide rates were stable. No trend changes occurred around 1960 or 1990. Conclusions The introduction of antidepressants around 1960 and the sharp increase in prescriptions after 1990 with the introduction of the SSRIs did not coincide with trend changes in suicide rates in Italy, Austria or Switzerland.

Risk of disease recurrence and mortality in gastrointestinal stromal tumor (GIST) patients receiving short-term versus long-term imatinib adjuvant therapy: A chart review analysis.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e20511-e20511
Author(s):  
Anthony Paul Conley ◽  
Annie Guerin ◽  
Medha Sasane ◽  
Genevieve Gauthier ◽  
Frances Schwiep ◽  
...  
Keyword(s):  
Extended Period ◽  
Disease Recurrence ◽  
Mortality Rates ◽  
Short Term ◽  
Online Data ◽  
Risk Of Recurrence ◽  
Adjusted Risk ◽  
Risk Of Disease ◽  
Collection Form

e20511 Background: The benefits of long-term (36 months) use of adjuvant imatinib (IM) in high risk GIST patients (pts) have been demonstrated in a recent multicenter, prospective clinical trial that compared efficacy and safety of 3 years vs 1 year IM treatment. However, in clinical practice, there is no consensus on the optimal IM treatment duration after surgery. The objective of this retrospective observational study was to compare the risk of recurrence and survival among primary resectable Kit positive GIST pts treated with adjuvant IM for a short vs an extended period of time in a real-world setting. Methods: Information on adult pts with primary resectable Kit positive GIST initiating imatinib ≤84 days after surgery was collected from 248 U.S. oncologists using an online data collection form. Detailed pt information following first GIST diagnosis, including demographic, GIST-related characteristics (e.g., risk profile), comorbidity profile, IM treatment characteristics, disease recurrence and mortality was collected for pts with short-term (6-12 months) and long-term IM use (≥24 months). Disease recurrence and mortality rates were estimated from the 1st surgery date to the 1st evidence of recurrence, mortality, or end of observation period. Multivariate Cox proportional hazard models were used to compare recurrence and mortality rates between short vs long term IM use pts. Results: Among the 246 short-term and 395 long-term IM pts, the median follow up was 884 and 963 days, respectively. The average age was similar [59.0 (10.4) vs 58.1 (9.5); p=.23] but short-term pts had less males [57.7% vs 69.6% (p<.01)] and a lower Miettinen risk score [0.3 vs 0.4, p< .01)] than long-term pts. Disease recurrence [7.3 vs 1.8%, (p< .01)] and mortality rates [6.9% vs 2.3%, (p < .01)] were also higher in short- vs long-term pts. The adjusted risk of recurrence was 4.77 times [95% CI: 1.98 – 11.48, (p<.01)] higher and mortality risk was 3.44 times [CI: 1.53 – 7.75, (p<.01)] higher in short- vs long-term pts. Conclusions: Use of IM over an extended period of time is associated with a reduction in long-term risk of disease recurrence and mortality.

scholarly journals Population signatures of large-scale, long-term disjunction and small-scale, short-term habitat fragmentation in an Afromontane forest bird

Heredity ◽  
2014 ◽  
Vol 113 (3) ◽  
pp. 205-214 ◽  
Author(s):  
J C Habel ◽  
R K Mulwa ◽  
F Gassert ◽  
D Rödder ◽  
W Ulrich ◽  
...  
Keyword(s):  
Habitat Fragmentation ◽  
Large Scale ◽  
Small Scale ◽  
Short Term ◽  
Forest Bird ◽  
Afromontane Forest

scholarly journals Measurement report: Short-term variation of ammonia concentration in an urban area: contributions of mist evaporation and emissions from a forest canopy with bird droppings

2020 ◽  
Author(s):  
Kazuo Osada
Keyword(s):  
Urban Area ◽  
Air Temperature ◽  
Forest Canopy ◽  
Leaf Growth ◽  
Anthropogenic Sources ◽  
Daily Maximum ◽  
Short Term ◽  
Daily Minimum ◽  
Bird Droppings ◽  
Morning Peak

Abstract. Short-term variations of NH3 concentrations in the urban atmosphere are affected by local meteorological conditions and variations of natural and anthropogenic sources. To investigate potential sources and processes of NH3 variation in an urban area, hourly NH3 and NH4+ concentrations were measured from November 2017 through October 2019 in Nagoya, a megacity located in central Japan. Monthly averages of NH3 concentrations were high in summer and low in winter. Daily minimum NH3 concentrations were almost linearly correlated with daily minimum air temperature. In contrast, daily maximum NH3 concentrations revealed an exponential increase with temperature, suggesting that different processes with air temperature acted during the nighttime and daytime. Short-term increases of NH3 concentrations of two types were examined closely. The first is a rare but large increase (11 ppb for 2 hr) after mist evaporation during daytime. It is noteworthy that an event of this magnitude was identified only once during two years of observations at Nagoya even though evaporation of mist or fog droplets is expected to be frequent after rain. The second short-term increase was a large morning peak in summer. After selected days were fulfilled with non-wet and weak wind conditions, the amplitude of diurnal variation of NH3 concentration (daily maximum minus minimum) was analyzed: the amplitude was small (ca. 2 ppb) in winter but it increased from early summer along with new leaf growth. It peaked in summer (up to ca. 20 ppb) during intense addition of droppings from hundreds of crows on trees in the campus assembled before roosting. The high daily maximum NH3 concentration was characterized by a rapid increase occurring 2–4 hr after local sunrise. Daily and seasonal findings related to the morning peak implied that stomatal emission at the site was responsible for the increase. The yearly difference between daily amplitudes during the two summers was explained by the difference in the input amounts of reactive nitrogen derived from bird droppings and some rain, suggesting that the canopy of a small forest affected by the bird droppings might act as a temporary but strong source of NH3.

scholarly journals Bamboo Water Transport Assessed with Deuterium Tracing

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 623 ◽  
Author(s):  
Tingting Mei ◽  
Dongming Fang ◽  
Alexander Röll ◽  
Dirk Hölscher
Keyword(s):  
Water Transport ◽  
Water Use ◽  
Extended Period ◽  
Sap Flux ◽  
Short Term ◽  
The Difference ◽  
Highly Correlated ◽  
Species Specific ◽  
Water Use Rates ◽  
Deuterium Tracing

Bamboo water transport comprises the pathway rhizomes-culms-leaves as well as transfer among culms via connected rhizomes. We assessed bamboo water transport in three big clumpy bamboo species by deuterium tracing. The tracer was injected into the base of established culms, and water samples were collected from leaves of the labeled culms and from neighboring culms. From the base of labeled culms to their leaves, the average tracer arrival time across species was 1.2 days, maximum tracer concentration was reached after 1.8 days, and the tracer residence time was 5.6 days. Sap velocities were high (13.9 m d−1). Daily culm water use rates estimated by the tracer method versus rates measured by a calibrated sap flux method were highly correlated (R2 = 0.94), but the tracer estimates were about 70% higher. Elevated deuterium concentrations in studied neighbor culms point to deuterium transfer among culms, which may explain the difference in culm water use estimates. We found no differences in deuterium concentrations between neighbor-established and neighbor freshly sprouted culms of a given species. In two species, elevated concentrations in both neighbor-established and neighbor freshly sprouted culms were observed over an extended period. An applied mixing model suggests that five neighbor culms received labeled water. In contrast, for the third species, elevated concentrations in neighbor culms were only observed at the earliest sampling date after labeling. This could indicate that there was only short-term transfer and that the tracer was distributed more widely across the rhizome network. In conclusion, our deuterium tracing experiments point to water transfer among culms, but with species-specific differences.

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