Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 7 de 7
Filter
Add more filters










Publication year range
1.
Ecology ; 105(4): e4238, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38212148

ABSTRACT

Growing evidence supports the hypothesis that temperate herbivores surf the green wave of emerging plants during spring migration. Despite the importance of autumn migration, few studies have conceptualized resource tracking of temperate herbivores during this critical season. We adapted the frost wave hypothesis (FWH), which posits that animals pace their autumn migration to reduce exposure to snow but increase acquisition of forage. We tested the FWH in a population of mule deer in Wyoming, USA by tracking the autumn migrations of n = 163 mule deer that moved 15-288 km from summer to winter range. Migrating deer experienced similar amounts of snow but 1.4-2.1 times more residual forage than if they had naïve knowledge of when or how fast to migrate. Importantly, deer balanced exposure to snow and forage in a spatial manner. At the fine scale, deer avoided snow near their mountainous summer ranges and became more risk prone to snow near winter range. Aligning with their higher tolerance of snow and lingering behavior to acquire residual forage, deer increased stopover use by 1 ± 1 day (95% CI) day for every 10% of their migration completed. Our findings support the prediction that mule deer pace their autumn migration with the onset of snow and residual forage, but refine the FWH to include movement behavior en route that is spatially dynamic.


Subject(s)
Deer , Animals , Animal Migration , Seasons , Herbivory , Equidae
2.
Ecol Evol ; 13(7): e10282, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37484933

ABSTRACT

Animal movement is the mechanism connecting landscapes to fitness, and understanding variation in seasonal animal movements has benefited from the analysis and categorization of animal displacement. However, seasonal movement patterns can defy classification when movements are highly variable. Hidden Markov movement models (HMMs) are a class of latent-state models well-suited to modeling movement data. Here, we used HMMs to assess seasonal patterns of variation in the movement of pronghorn (Antilocapra americana), a species known for variable seasonal movements that challenge analytical approaches, while using a population of mule deer (Odocoileus hemionus), for whom seasonal movements are well-documented, as a comparison. We used population-level HMMs in a Bayesian framework to estimate a seasonal trend in the daily probability of transitioning between a short-distance local movement state and a long-distance movement state. The estimated seasonal patterns of movements in mule deer closely aligned with prior work based on indices of animal displacement: a short period of long-distance movements in the fall season and again in the spring, consistent with migrations to and from seasonal ranges. We found seasonal movement patterns for pronghorn were more variable, as a period of long-distance movements in the fall was followed by a winter period in which pronghorn were much more likely to further initiate and remain in a long-distance movement pattern compared with the movement patterns of mule deer. Overall, pronghorn were simply more likely to be in a long-distance movement pattern throughout the year. Hidden Markov movement models provide inference on seasonal movements similar to other methods, while providing a robust framework to understand movement patterns on shorter timescales and for more challenging movement patterns. Hidden Markov movement models can allow a rigorous assessment of the drivers of changes in movement patterns such as extreme weather events and land development, important for management and conservation.

3.
Nat Commun ; 14(1): 2008, 2023 04 10.
Article in English | MEDLINE | ID: mdl-37037806

ABSTRACT

Billions of animals migrate to track seasonal pulses in resources. Optimally timing migration is a key strategy, yet the ability of animals to compensate for phenological mismatches en route is largely unknown. Using GPS movement data collected from 72 adult female deer over a 10-year duration, we study a population of mule deer (Odocoileus hemionus) in Wyoming that lack reliable cues on their desert winter range, causing them to start migration 70 days ahead to 52 days behind the wave of spring green-up. We show that individual deer arrive at their summer range within an average 6-day window by adjusting movement speed and stopover use. Late migrants move 2.5 times faster and spend 72% less time on stopovers than early migrants, which allows them to catch the green wave. Our findings suggest that ungulates, and potentially other migratory species, possess cognitive abilities to recognize where they are in space and time relative to key resources. Such behavioral capacity may allow migratory taxa to maintain foraging benefits amid rapidly changing phenology.


Subject(s)
Deer , Animals , Female , Animal Migration , Ecosystem , Seasons , Equidae
5.
BIS, Bol. Inst. Saúde (Impr.) ; 24(2): 171-178, 2023.
Article in Portuguese | CONASS, Sec. Est. Saúde SP, SESSP-ISPROD, Sec. Est. Saúde SP, SESSP-ISACERVO | ID: biblio-1527470

ABSTRACT

O estudo discute as competências envolvidas na condução de rodas de conversas. Trata-se de um relato analítico e reflexivo desenvolvido a partir das experiências dos estudantes da disciplina de Promoção da Saúde de um programa de Mestrado Profissional em Saúde da Família, Mato Grosso do Sul, Brasil. As experiências foram registradas no formato de relatórios de experiências e enfatizaram o uso de rodas de conversas em Unidades de Saúde da Família. A partir do corpus documental, foram levantados o público- alvo, temáticas/objetivos e quatro competências aplicadas para o desenvolvimento das rodas de conversa, a saber: aprender a conhecer, aprender a fazer, aprender a conviver, e aprender a ser. Observou-se que o público-alvo e as temáticas desenvolvidas nas rodas de conversas foram relacionados a situação epidemiológica do território. Ainda, foi identificado que a técnica é frequentemente baseada no referencial teórico de Paulo Freire, com etapas sistematizadas. As competências de saber conhecer e saber fazer foram desafiantes. As competências saber conviver e ser destacaram- se positivamente nas experiências descritas. Por fim, as experiências revelaram que há competências que precisam ser aprimoradas para a condução de rodas de conversas, com vistas a alcançar o seu potencial transformador.


Subject(s)
Primary Health Care , Health Promotion , Health Education
6.
Microorganisms ; 11(1)2022 Dec 25.
Article in English | MEDLINE | ID: mdl-36677355

ABSTRACT

Phytoplankton is fundamental to life on Earth. Their productivity is influenced by the microbial communities residing in the phycosphere surrounding algal cells. Expanding our knowledge on how algal-bacterial interactions affect algal growth to more hosts and bacteria can help elucidate general principles of algal-host interactions. Here, we isolated 368 bacterial strains from phycosphere communities, right after phycosphere recruitment from pond water and after a month of lab cultivation and examined their impacts on growth of five green algal species. We isolated both abundant and rare phycosphere members, representing 18.4% of the source communities. Positive and neutral effects predominated over negative effects on host growth. The proportion of each effect type and whether the day of isolation mattered varied by host species. Bacteria affected algal carrying capacity more than growth rate, suggesting that nutrient remineralization and toxic byproduct metabolism may be a dominant mechanism. Across-host algal fitness assays indicated host-specific growth effects of our isolates. We observed no phylogenetic conservation of the effect on host growth among bacterial isolates. Even isolates with the same ASV had divergent effects on host growth. Our results emphasize highly specific host-bacterial interactions in the phycosphere and raise questions as to which mechanisms mediate these interactions.

7.
Curr Biol ; 30(17): 3444-3449.e4, 2020 09 07.
Article in English | MEDLINE | ID: mdl-32619482

ABSTRACT

Animals exhibit a diversity of movement tactics [1]. Tracking resources that change across space and time is predicted to be a fundamental driver of animal movement [2]. For example, some migratory ungulates (i.e., hooved mammals) closely track the progression of highly nutritious plant green-up, a phenomenon called "green-wave surfing" [3-5]. Yet general principles describing how the dynamic nature of resources determine movement tactics are lacking [6]. We tested an emerging theory that predicts surfing and the existence of migratory behavior will be favored in environments where green-up is fleeting and moves sequentially across large landscapes (i.e., wave-like green-up) [7]. Landscapes exhibiting wave-like patterns of green-up facilitated surfing and explained the existence of migratory behavior across 61 populations of four ungulate species on two continents (n = 1,696 individuals). At the species level, foraging benefits were equivalent between tactics, suggesting that each movement tactic is fine-tuned to local patterns of plant phenology. For decades, ecologists have sought to understand how animals move to select habitat, commonly defining habitat as a set of static patches [8, 9]. Our findings indicate that animal movement tactics emerge as a function of the flux of resources across space and time, underscoring the need to redefine habitat to include its dynamic attributes. As global habitats continue to be modified by anthropogenic disturbance and climate change [10], our synthesis provides a generalizable framework to understand how animal movement will be influenced by altered patterns of resource phenology.


Subject(s)
Animal Migration/physiology , Climate Change , Deer/physiology , Ecosystem , Plant Development , Plant Physiological Phenomena , Plants/metabolism , Animals , Geographic Information Systems , Herbivory
SELECTION OF CITATIONS
SEARCH DETAIL
...