H. Casper results 46
· Newest (Page 1/2, per page 25)
Author: H. Casper ×Clear All Filters
Search Results
Knowledge of which animal clades and dispersal mechanisms contribute to seed dispersal is critical for understanding the ecology and evolution of plant communities. However, a broad understanding is limited by a focus on single clades and mechanisms. Here, we analyzed a Europe‐wide multi‐clade seed dispersal dataset with interactions among 447 animal species and 1901 plant species via four dispersal mechanisms: endozoochory (i...
Smallholder households across rural sub-Saharan Africa often rely on goats to support their livelihoods, food security, and financial security, and as a risk mitigation strategy. Across the region, goat health and performance outcomes vary greatly, and it is often difficult to quantify the impact of the animal health-nutrition nexus on livelihood outcomes. Two socio-economic surveys were conducted to this end in Botswana. Firs...
Estimating Time‐Varying Productivity and Reference Points: A Case of North Sea Demersal Fish StocksNARA Subscribed
The productivity of marine fish populations determines both maximum sustainable yield (MSY) and resilience to exploitation. While biological reference points like MSY and depend on species traits and population density, they are also influenced by environmental variability and ecological interactions. However, commonly used models, such as stock–recruitment and surplus production models (SPMs), often assume constant productivi...
Diabetes and other age-related diseases are associated with an increased risk of cognitive impairment, but the underlying mechanisms remain poorly understood. Methylglyoxal (MGO), a by-product of glycolysis and a major precursor in the formation of advanced glycation end-products (AGEs), is increased in individuals with diabetes and other age-related diseases and is associated with microvascular dysfunction. We now investigate...
Tundra Vegetation Community Type, Not Microclimate, Controls Asynchrony of Above‐ and Below‐Ground PhenologyNARA Subscribed
The below‐ground growing season often extends beyond the above‐ground growing season in tundra ecosystems and as the climate warms, shifts in growing seasons are expected. However, we do not yet know to what extent, when and where asynchrony in above‐ and below‐ground phenology occurs and whether variation is driven by local vegetation communities or spatial variation in microclimate. Here, we combined above‐ and below‐ground...
The nutritional feed gap: Seasonal variations in ruminant nutrition and knowledge gaps in relation to food security in Southern AfricaNARA Subscribed
Livestock production is critical to food security and rural livelihoods across Southern Africa. Despite progress in livestock science research in recent years, the seasonal availability and quality of feed remains one of the key challenges to livestock productivity in Southern Africa. In particular, dry weather conditions, the lack of rain and lower temperatures in the dry season cause herbaceous plants to die back and browse...
Environmental Conditions Modulate Warming Effects on Plant Litter Decomposition GloballyNARA Subscribed
Empirical studies worldwide show that warming has variable effects on plant litter decomposition, leaving the overall impact of climate change on decomposition uncertain. We conducted a meta‐analysis of 109 experimental warming studies across seven continents, using natural and standardised plant material, to assess the overarching effect of warming on litter decomposition and identify potential moderating factors. We determin...
Multiple Pleistocene refugia for Arctic Bell‐Heather revealed with genomic analyses of modern and historic plantsNARA Subscribed
Aim Arctic plants survived the Pleistocene glaciations in unglaciated refugia. The number, ages, and locations of these refugia are often unclear. We use high‐resolution genomic data from present‐day and Little‐Ice‐Age populations of Arctic Bell‐Heather to re‐evaluate the biogeography of this species and determine whether it had multiple independent refugia or a single refugium in Beringia. Location Circumpolar Arctic and Coas...
Float, fly, then sink: wetland plant seed buoyancy is lost after internal dispersal by waterbirdsNARA Subscribed
Seed dispersal distance is an important indicator of how well a plant species can cope with environmental changes. Seeds of wetland plants are primarily dispersed by hydrochory (floating on the water surface) or endozoochory (ingestion and egestion by animals). However, both mechanisms can also be combined (diplochory), which increases dispersal distances. In wetlands, seeds often float on the water surface before ingestion an...
Reading tea leaves worldwide: Decoupled drivers of initial litter decomposition mass‐loss rate and stabilizationNARA Subscribed
The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large‐scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass‐loss rates and stabilization factors of plant‐derived carbon, using the Tea...
Individual differences in GHB consumption in a new voluntary GHB self-administration model in outbred ratsNARA Subscribed
Background and purpose The use of the recreational drug gamma-hydroxybutyric acid (GHB) has increased over the past decade, concomitantly leading to a higher incidence of GHB use disorder. Evidence-based treatment interventions are hardly available and cognitive effects of long-term GHB use remain elusive. In order to study the development of GUD and the causal effects of chronic GHB consumption, a GHB self-administration mode...
Extracerebral microvascular dysfunction is related to brain MRI markers of cerebral small vessel disease: The Maastricht StudyNARA Subscribed
Background Cerebral small vessel disease (cSVD) is a late consequence of cerebral microvascular dysfunction (MVD). MVD is hard to measure in the brain due to its limited accessibility. Extracerebral MVD (eMVD) measures can give insights in the etiology of cerebral MVD, as MVD may be a systemic process. We aim to investigate whether a compound score consisting of several eMVD measures is associated with structural cSVD MRI mark...
Patient-reported burden of intensified surveillance and surgery in high-risk individuals under pancreatic cancer surveillanceNARA Subscribed
In high-risk individuals participating in a pancreatic cancer surveillance program, worrisome features warrant for intensified surveillance or, occasionally, surgery. Our objectives were to determine the patient-reported burden of intensified surveillance and/or surgery, and to assess post-operative quality of life and opinion of surgery. Participants in our pancreatic cancer surveillance program completed questionnaires inclu...
Invasive silver carp is empirically linked to declines of native sport fish in the Upper Mississippi River SystemNARA Subscribed
Empirical assessments of the influence of invasive species on native species are infrequent because the required long-term data are rarely available. The invasion of silver carp in the Upper Mississippi River System (UMRS) provides a unique opportunity to assess the influence of this invasive species on native fishes because a highly standardized, long-term monitoring program has been sampling the fish communities in six reach...
Arctic climate warming will be primarily during winter, resulting in increased snowfall in many regions. Previous tundra research on the impacts of deepened snow has generally been of short duration. Here, we report relatively long‐term (7–9 years) effects of experimentally deepened snow on plant community structure, net ecosystem CO 2 exchange ( NEE ), and soil biogeochemistry in Canadian Low Arctic mesic shrub tundra. The sn...