‘Unscrambling’ the drivers of egg production in Agassiz’s desert tortoise: Climate and individual attributes predict reproductive output
Links
- More information: Publisher Index Page (via DOI)
- Data Releases:
- USGS data release - Mojave Desert Tortoise (Gopherus agassizii) Morphometrics and Egg Data from Seven Sites across the Mojave, (1997-2002)
- USGS data release - Agassiz's desert tortoise and egg data from the Sonoran Desert of California (1997-2000, 2015-2018)
- Open Access Version: Publisher Index Page
- Download citation as: RIS | Dublin Core
Abstract
ABSTRACT: The ‘bet hedging’ life history strategy of long-lived iteroparous species reduces short-term reproductive output to minimize the risk of reproductive failure over a lifetime. For desert-dwelling ectotherms living in variable and unpredictable environments, reproductive output is further influenced by precipitation and temperature via effects on food availability and limits on activity. We assembled multiple (n = 12) data sets on egg production for the threatened Agassiz’s desert tortoise Gopherus agassizii across its range and used these data to build a range-wide predictive model of annual reproductive output as a function of annual weather variation and individual-level attributes (body size and prior-year reproductive status). Climate variables were more robust predictors of reproductive output than individual-level attributes, with overall reproductive output positively related to prior-year precipitation and an earlier start to the spring activity season, and negatively related to spring temperature extremes (monthly temperature range in March-April). Reproductive output was highest for individuals with larger body sizes that reproduced in the previous year. Expected annual reproductive output from 1990-2018 varied from 2-5 to 6-12 eggs female-1 yr-1 , with a weak decline in expected reproductive output over this time (p = 0.02). Climate-driven environmental variation in expected reproductive output was highly correlated across all 5 Recovery Units for this species (Pearson’s r > 0.9). Overall, our model suggests that climate change could strongly impact the reproductive output of Agassiz’s desert tortoise, and could have a negative population-level effect if precipitation is significantly reduced across the species’ range as predicted under some climate models.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | ‘Unscrambling’ the drivers of egg production in Agassiz’s desert tortoise: Climate and individual attributes predict reproductive output |
| Series title | Endangered Species Research |
| DOI | 10.3354/esr01103 |
| Volume | 44 |
| Year Published | 2021 |
| Language | English |
| Publisher | Inter-Research Science Publisher |
| Contributing office(s) | Southwest Biological Science Center, Western Ecological Research Center |
| Description | 14 p. |
| First page | 217 |
| Last page | 230 |
| Country | United States |
| State | California, Arizona, Nevada, Utah |
| Google Analytic Metrics | Metrics page |