The influence of intraspecific trait variation on species interactions makes trait-based approaches critical to understanding eco-evolutionary processes. Because species occupy habitats that are ...patchily distributed in space, species interactions are influenced not just by the degree of intraspecific trait variation but also the relative proportion of trait variation that occurs within- versus between-patches. Advancement in trait-based ecology hinges on understanding how trait variation is distributed within and between habitat patches across the landscape. We sampled larval spotted salamanders (Ambystoma maculatum) across six spatially discrete ponds to quantify within- and between-pond variation in mass, length, and various metrics associated with their relationship (scaling, body condition, shape). Across all traits, within-pond variation contributed more to total observed morphological variation than between-pond variation. Between-pond variation was not negligible, however, and explained 20-41% of total observed variation in measured traits. Between-pond variation was more pronounced in salamander tail morphology compared to head or body morphology, suggesting that pond-level factors more strongly influence tails than other body parts. We also observed differences in mass-length relationships across ponds, both in terms of scaling slopes and intercepts, though differences in the intercepts were much stronger. Preliminary evidence hinted that newly constructed ponds were a driver of the observed differences in mass-length relationships and morphometrics. General pond-level difference in salamander trait covariation suggest that allometric scaling of morphological traits is context dependent in patchy landscapes. Effects of pond age offer the hypothesis that habitat restoration through pond construction is a driver of variation in trait scaling, which managers may leverage to bolster trait diversity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Major advancements in ecology and biodiversity conservation have been made thanks to methods for marking and individually tracking animals. Marking animals is both widely used and controversial due ...to the potential consequences for animal welfare, which are often incompletely evaluated prior to implementation. Two outstanding knowledge gaps concerning the welfare consequences of individual marking are their short-term behavioural impacts and the relative impacts from marking versus the handling of animals while carrying out procedures. We addressed these knowledge gaps through an experimental study of alpine newts (
) in which we varied handling and marking procedures. Examining individual responses to handling, toe clipping and visible implant elastomer (VIE) injection over 21 days showed that handling and marking elicited increased newt activity and hesitancy to feed compared to animals that did not get handled or marked. These effects were apparent even when animals were handled only (not marked), and marking did not further increase the magnitude of responses. Increases in newt activity and feeding hesitancy were transient; they were not observed in the weeks following handling and marking. While previous studies emphasise the welfare impacts of marking procedures themselves, these findings highlight that handling alone can elicit behavioural changes with possible costs to welfare. Yet, the transient nature of behavioural responses suggests that immediate costs of handling may be subsequently compensated for in the short term.
The level of detail on host communities needed to understand multihost parasite invasions is an unresolved issue in disease ecology. Coarse community metrics that ignore functional differences ...between hosts, such as host species richness, can be good predictors of invasion outcomes. Yet if host species vary in the extent to which they maintain and transmit infections, then explicitly accounting for those differences may be important. Through controlled mesocosm experiments and modeling, we show that interspecific differences between host species are important for community-wide infection dynamics of the multihost fungal parasite of amphibians (Batrachochytrium dendrobatidis Bd), but only up to a point. The most abundant host species in our system, fire salamander larvae (Salamandra salamandra), did not maintain or transmit infections. Rather, two less abundant “auxiliary” host species, Iberian tree frog (Hyla molleri) and spiny toad (Bufo spinosus) larvae, maintained and transmitted Bd. Frogs had the highest mean rates of Bd shedding, giving them the highest contributions to the basic reproduction number, R0. Toad contributions to R0 were substantial, however, and when examining community-level patterns of infection and transmission, the effects of frogs and toads were similar. Specifying more than just host species richness to distinguish salamanders from auxiliary host species was critical for predicting community-level Bd prevalence and transmission. Distinguishing frogs from toads, however, did not improve predictions. These findings demonstrate limitations to the importance of host species identities in multihost infection dynamics. Host species that exhibit different functional traits, such as susceptibility and infectiousness, may play similar epidemiological roles in the broader community.
Animals switch habitats on a regular basis, and when habitats vary in suitability for parasitism, routine habitat switching alters the frequency of parasite exposure and may affect post‐infection ...parasite proliferation. However, the effects of routine habitat switching on infection dynamics are not well understood.
We performed infection experiments, behavioural observations and field surveillance to evaluate how routine habitat switching by adult alpine newts (Ichthyosaura alpestris) influences infection dynamics of the pathogenic parasite, Batrachochytrium dendrobatidis (Bd).
We show that when newts are exposed to equal total doses of Bd in aquatic habitats, differences in exposure frequency and post‐exposure habitat alter infection trajectories: newts developed more infections that persisted longer when doses were broken into multiple, reduced‐intensity exposures. Intensity and persistence of infections were reduced among newts that were switched to terrestrial habitats following exposure.
When presented with a choice of habitats, newts did not avoid exposure to Bd, but heavily infected newts were more prone to reduce time spent in water.
Accounting for routine switching between aquatic and terrestrial habitat in the experiments generated distributions of infection loads that were consistent with those in two populations of wild newts.
Together, these findings emphasize that differential habitat use and behaviours associated with daily movement can be important ecological determinants of infection risk and severity.
A plain language summary is available for this article.
Plain Language Summary
Free-living eukaryotic microbes may reduce animal diseases. We evaluated the dynamics by which micrograzers (primarily protozoa) apply top-down control on the chytrid
(
) a devastating, panzootic ...pathogen of amphibians. Although micrograzers consumed zoospores (∼3 μm), the dispersal stage of chytrids, not all species grew monoxenically on zoospores. However, the ubiquitous ciliate
, which likely co-occurs with
, grew at near its maximum rate (
= 1.7 d
). A functional response (ingestion vs. prey abundance) for
, measured using spore-surrogates (microspheres) revealed maximum ingestion (
) of 1.63 × 10
zoospores d
, with a half saturation constant (
) of 5.75 × 10
zoospores ml
. Using these growth and grazing data we developed and assessed a population model that incorporated chytrid-host and micrograzer dynamics. Simulations using our data and realistic parameters obtained from the literature suggested that micrograzers could control
and potentially prevent chytridiomycosis (defined as 10
sporangia host
). However, simulated inferior micrograzers (0.7 ×
and 1.5 ×
) did not prevent chytridiomycosis, although they ultimately reduced pathogen abundance to below levels resulting in disease. These findings indicate how micrograzer responses can be applied when modeling disease dynamics for
and other zoosporic fungi.
Risks of parasitism vary over time, with infection prevalence often fluctuating with seasonal changes in the annual cycle. Identifying the biological mechanisms underlying seasonality in infection ...can enable better prediction and prevention of future infection peaks. Obtaining longitudinal data on individual infections and traits across seasons throughout the annual cycle is perhaps the most effective means of achieving this aim, yet few studies have obtained such information for wildlife. Here, we tracked spiny common toads (
) within and across annual cycles to assess seasonal variation in movement, body temperatures and infection from the fungal parasite,
. Across annual cycles, toads did not consistently sustain infections but instead gained and lost infections from year to year. Radio-tracking showed that infected toads lose infections during post-breeding migrations, and no toads contracted infection following migration, which may be one explanation for the inter-annual variability in
infections. We also found pronounced seasonal variation in toad body temperatures. Body temperatures approached 0 °C during winter hibernation but remained largely within the thermal tolerance range of
. These findings provide direct documentation of migratory recovery (i.e., loss of infection during migration) and escape in a wild population. The body temperature reductions that we observed during hibernation warrant further consideration into the role that this period plays in seasonal
dynamics.
We currently face significant, anthropogenic, global environmental challenges and the role of ecologists in mitigating these challenges is arguably more important than ever. Consequently there is an ...urgent need to recruit and train future generations of ecologists, both those whose main area is ecology, but also those involved in the geological, biological and environmental sciences.
Here we present the results of a horizon scanning exercise that identified current and future challenges facing the teaching of ecology, through surveys of teachers, students and employers of ecologists. Key challenges identified were grouped in terms of the perspectives of three groups: students, for example the increasing disconnect between people and nature; teachers, for example the challenges associated with teaching the quantitative skills that are inherent to the study of ecology; and society, for example poor societal perceptions of the field of ecology.
In addition to the challenges identified, we propose a number of solutions developed at a workshop by a team of ecology teaching experts, with supporting evidence of their potential to address many of the problems raised. These proposed solutions include developing living labs, teaching students to be ecological entrepreneurs and influencers, embedding skills‐based learning and coding in the curriculum, an increased role for learned societies in teaching and learning, and using new technology to enhance fieldwork studies including virtual reality, artificial intelligence and real‐time spoken language translation.
Our findings are focused towards UK higher education, but they should be informative for students and teachers of a wide range of educational levels, policy makers and professional ecologists worldwide.
The influence of intraspecific trait variation on species interactions makes trait-based approaches critical to understanding eco-evolutionary processes. Because species occupy habitats that are ...patchily distributed in space, species interactions are influenced not just by the degree of intraspecific trait variation but also the relative proportion of trait variation that occurs within- versus between-patches. Advancement in trait-based ecology hinges on understanding how trait variation is distributed within and between habitat patches across the landscape. We sampled larval spotted salamanders (Ambystoma maculatum) across six spatially discrete ponds to quantify within- and between-pond variation in mass, length, and various metrics associated with their relationship (scaling, body condition, shape). Across all traits, within-pond variation contributed more to total observed morphological variation than between-pond variation. Between-pond variation was not negligible, however, and explained 20-41% of total observed variation in measured traits. Between-pond variation was more pronounced in salamander tail morphology compared to head or body morphology, suggesting that pond-level factors more strongly influence tails than other body parts. We also observed differences in mass-length relationships across ponds, both in terms of scaling slopes and intercepts, though differences in the intercepts were much stronger. Preliminary evidence hinted that newly constructed ponds were a driver of the observed differences in mass-length relationships and morphometrics. General pond-level difference in salamander trait covariation suggest that allometric scaling of morphological traits is context dependent in patchy landscapes. Effects of pond age offer the hypothesis that habitat restoration through pond construction is a driver of variation in trait scaling, which managers may leverage to bolster trait diversity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Novel outbreaks of emerging pathogens require rapid responses to enable successful mitigation. We simulated a 1‐day emergency meeting where experts were engaged to recommend mitigation strategies for ...a new outbreak of the amphibian fungal pathogen Batrachochytrium salamandrivorans. Despite the inevitable uncertainty, experts suggested and discussed several possible strategies. However, their recommendations were undermined by imperfect initial definitions of the objectives and scope of management. This problem is likely to arise in most real‐world emergency situations. The exercise thus highlighted the importance of clearly defining the context, objectives, and spatial–temporal scale of mitigation decisions. Managers are commonly under pressure to act immediately. However, an iterative process in which experts and managers cooperate to clarify objectives and uncertainties, while collecting more information and devising mitigation strategies, may be slightly more time consuming but ultimately lead to better outcomes.
Many organisms avoid habitats posing risks of parasitism. Parasites are not generally conspicuous, however, which raises the question of what cues individuals use to detect parasitism risk. Here, we ...provide evidence in alpine newts (
Ichthyosaura alpestris
) that non-visual cues from parasite-exposed conspecifics inform habitat avoidance. Alpine newts breed in aquatic habitats and occasionally move among adjacent terrestrial habitat during breeding seasons. We completed experiments with newts whereby individuals had access to both habitats, and the aquatic habitats varied in prior occupancy by conspecifics with different histories of exposure to the parasitic skin fungus,
Batrachochytrium dendrobatidis
(
Bd
). Continuous filming of newt activity for 2 days provided little evidence that prior use of aquatic habitats by conspecifics, regardless of their
Bd
exposure history, immediately influenced newt habitat use. However, newts that encountered aquatic habitats used specifically by
Bd
-exposed conspecifics on day 1 spent less time aquatic on day 2, whereas other newts did not alter habitat use. Responses could have been elicited by cues generated by
Bd
stages on the conspecifics or, perhaps more likely, cues emitted by the conspecifics themselves. In either case, these observations suggest that newts use non-visual cues sourced from exposed conspecifics to detect
Bd
risk and that those cues cause newts to avoid aquatic habitats.
Bd
may therefore influence host behavior in early phases of interactions, and possibly before any contact with infectious stages is made, creating potential for non-consumptive effects.
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