Investigating temporal changes and effects of elevation on the prevalence of a rickettsial blood parasite in red-backed salamanders (Plethodon cinereus) in Virginia, USA

Davis, Andrew K.; Toledo, Gabriela; Richards, Robert J.

doi:10.1007/s00580-016-2299-9

Cited by 2 publications

(2 citation statements)

References 23 publications

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“…The positive association between riparian forest cover and parasite status described herein is remarkably consistent with the positive associations between forest cover and metrics of hellbender status that have been previously described ( Bodinof Jachowski and Hopkins, 2018 ; Bodinof Jachowski et al , 2016 ; Hopkins et al , 2023 ) and suggest that the distribution of our focal parasites was largely determined by the underlying patterns of local abundance of hellbender hosts which respond positively to riparian forest cover ( Bodinof Jachowski and Hopkins, 2018 ). Our findings are consistent with patterns of parasitism in some other salamanders ( Plethodon cinereus, Davis et al 2016 ) and, when viewed collectively, are indicative of classic density-dependent parasite transmission ( Dietz, 1988 ). We are thus led to conclude that, in our system, stream reaches of highest abiotic quality not only harbor the highest density of hellbenders, but also present the greatest risk of hellbenders contracting leech and trypanosome infections.…”

Section: Discussionsupporting

confidence: 87%

The habitat quality paradox: loss of riparian forest cover leads to decreased risk of parasitism and improved body condition in an imperiled amphibian

Bodinof Jachowski,

Alaasam,

Blumenthal

et al. 2024

Conservation Physiology

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Amphibian declines are a global phenomenon but responses of populations to specific threats are often context dependent and mediated by individual physiological condition. Habitat degradation due to reduced riparian forest cover and parasitism are two threats facing the hellbender salamander (Cryptobranchus alleganiensis), but their potential to interact in nature remains largely unexplored. We investigated associations between forest cover, parasitic infection and physiology of hellbenders to test the hypotheses that physiological condition responds to infection and/or habitat degradation. We sampled 17 stream reaches in southwest Virginia, USA, on a year-round basis from 2013 to 2016 and recorded 841 captures of 405 unique hellbenders. At each capture we documented prevalence of two blood-associated parasites (a leech and trypanosome) and quantified up to three physiological condition indices (body condition, hematocrit, white blood cell [WBC] differentials). We used generalized linear mixed models to describe spatiotemporal variation in parasitic infection and each condition index. In general, living in the most heavily forested stream reaches, where hellbender density was highest, was associated with the greatest risk of parasitism, elevated neutrophil-to-lymphocyte (N:L) ratios and eosinophils, slightly lower hematocrit and lower mean body condition in hellbenders. All condition indices fluctuated temporally in a manner consistent with seasonal variation in hellbender metabolic demands and breeding phenology and were associated with land use during at least part of the year. Paradoxically, relatively low levels of forest cover appeared to confer a potential advantage to individuals in the form of release from parasites and improved body condition. Despite improved body condition, individuals from less forested areas failed to exhibit fluctuating body condition in response to spawning, which was typical in hellbenders from more forested habitats. We postulate this lack of fluctuation could be due to reduced conspecific competition or reproductive investment and/or high rates of filial cannibalism in response to declining forest cover.

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Section: Discussionsupporting

confidence: 87%

The habitat quality paradox: loss of riparian forest cover leads to decreased risk of parasitism and improved body condition in an imperiled amphibian

Bodinof Jachowski,

Alaasam,

Blumenthal

et al. 2024

Conservation Physiology

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“…While it is often thought that parasites are most common in warmer environments near the equator and at lower elevations, a recent meta‐analysis found that parasitism instead increases towards the poles (Zvereva & Kozlov, 2021). Evidence for patterns along elevational gradients is mixed, with some cases where the prevalence of infection decreases at higher elevations (Bears, 2004; Meléndez et al, 2014; Zamora‐Vilchis et al, 2012; Zanet et al, 2017) but others that show the opposite trend (Álvarez‐Ruiz et al, 2018; Davis et al, 2016; Schai‐Braun et al, 2019), or even prevalence peaks at mid‐elevations (Bodawatta et al, 2020). One possible resolution to these conflicting reports is that patterns differ among different lineages of parasites (González et al, 2014; Merino et al, 2008; Preisser, 2019).…”

Section: Introductionmentioning

confidence: 99%

Host phylogeny and elevation predict infection by avian haemosporidians in a diverse New Guinean bird community

Lau

Freeman

Pulgarín‐R

et al. 2022

Journal of Biogeography

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Aim The biotic interactions hypothesis predicts that interactions between species are stronger at lower elevations compared to higher elevations. We tested whether this prediction is met by examining elevational patterns in avian haemosporidian infections in New Guinean birds. Location YUS Conservation Area, Papua New Guinea. Taxon Birds and haemosporidia. Methods We collected blood samples from 2268 individuals of 66 bird species along a reef‐to‐ridgetop tropical elevational gradient covering ~3000 m of elevation. We used molecular methods to screen samples for haemosporidian parasites, and sequenced 70% of positive infections to determine the identity of parasite genera. We fit a phylogenetic generalized mixed‐effects model to test whether infection prevalence was higher at low elevations, as predicted by the biotic interactions hypothesis. Finally, we tested for phylogenetic signal in parasite prevalence and in host elevational distribution using Pagel's λ. Results Overall parasite prevalence was 45%. Infection prevalence decreased with elevation, though prevalence remained above ~30% even for high‐elevation communities between 2000 and 3000 m. We found strong phylogenetic signal in infection prevalence, but no phylogenetic signal in host elevational distribution. Nearly all sequenced infections (97%) were of Haemoproteus. Main Conclusions Our results are consistent with predictions arising from the biotic interactions hypothesis. However, phylogenetic relationships among hosts are a much better predictor of infection prevalence than is elevational position: closely related bird species tend to have similar infection prevalence regardless of the elevations where they live.

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Investigating temporal changes and effects of elevation on the prevalence of a rickettsial blood parasite in red-backed salamanders (Plethodon cinereus) in Virginia, USA

Cited by 2 publications

References 23 publications

The habitat quality paradox: loss of riparian forest cover leads to decreased risk of parasitism and improved body condition in an imperiled amphibian

The habitat quality paradox: loss of riparian forest cover leads to decreased risk of parasitism and improved body condition in an imperiled amphibian

Host phylogeny and elevation predict infection by avian haemosporidians in a diverse New Guinean bird community

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