Targeted management approaches for minimizing Navy activity impacts on long-lived vertebrates
Abstract
Significant progress has been made linking behavior with health and vital rates to predict thepotential for a Population Consequence, of Disturbance (PCoD). PCoD models rely on inputparameters such as survival and reproductive rates that have generally been thought, toadequately represent the population. However, these demographic measures are typically derivedfrom population averages, thus assu,ming that the likelihood of reproduction is equivalent acrossindividuals. Recent research in long-lived vertebrates has discovered t,hat the likelihoods ofreproduction and survival are highly variable across individuals. Therefore, the populationconsequence of a di,sturbance is not likely to impact individuals across all demographic groupsequally. Some females might be particularly resilient to,disturbance whereas others might bemore sensitive. Data on northern elephant seals (Mirounga angustirostris) and bottlenosedolphins,(Tursiops truncatus) has shown that a few individuals appear to be more resilient tointerannual variations in resource limitation or, other stressors and thus disproportionatelycontribute to population viability; however, traits that contribute to this resilience a,re not known.We propose that targeted management should account for this individual heterogeneity because adisturbance can have a tr,emendously variable impact on population dynamics depending on thecharacteristics of the disturbed animals. To quantify the importan,ce of individual variability forPCoD efforts, we will utilize northern elephant seals. In this robust model system, critical data on,the phenological, ecological, physiological, and genetic drivers of lifetime fitness can beconsistently obtained. Our research will,leverage existing long-term data and produce new datato answer the following questions: (1) Which phenotypic and/or genotypic traits, mediate lifetimereproductive success (LRS)? (2) How does the relationship between chronological age (i.e., timesince birth) and bio,logical age (i.e., evaluating markers for DNA methylation in the blood) relateto LRS? (3) What are the implications of variation in,LRS for population dynamics andmanagement? First, we will evaluate whether phenotypic traits (at-sea behavior, diet, life-historyphe,nology) and/or genotype modulate individual heterogeneity in LRS. As an alternativeexplanation, we will explore whether variation in, LRS simply occurs due to random chance.Next, we will leverage existing samples to quantify similarities between chronological andbi,ological age and determine the degree to which LRS impacts these epigenetic metrics. Finally,we will synthesize the findings above b,y modeling the impact of variation in female LRS onpopulation dynamics under targeted versus random management approaches. Understan,ding thelocations, times, and predictive characteristics of the most demographically valuable individualscan help to strategically p,lan disturbances in space and time to minimize the impacts of Navyactivities. These findings will help quantify the population conse,quences of a naval exercise,which can be applied to other threatened, endangered, and at-risk species that are of high concernto the, ONR MMB Program. Our work will also set the stage for elucidating the interactionsbetween Navy exercises and climate change, as mar,ine mammal core habitats are displaced andpotentially overlap with active Navy sonar training areas. Finally, this work will involve, severalcohorts of undergraduate researchers, which will facilitate student engagement and increase thelikelihood that under-represe,nted students will join the STEM and DoD workforc
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 08, 2022
- Source ID
- N000142212707
Entities
People
- Roxanne S Beltran
Organizations
- Office of Naval Research
- United States Navy
- University of California, Santa Cruz