Implications for the future
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Life history characteristics and habitat selection of Opea KalaOle over a strong precipitation gradient: Implications for the future
Life history characteristics and habitat selection of Opae kalaole over a strong precipitation gradient
Implications for the future
Ralph W. Tingley III1, Richard MacKenzie2, Dana M. Infante1, Ayron M. Strauch3 Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI Institute of Pacific Island Forestry, Pacific Southwest Research Station, Hilo, HI University of Hawaii, Manoa, HI
Hello everyone and thank you for making it to my talk today. First, I would just like to say that we are in the very early steps of this process and any input on sampling methods or design would be greatly appreciated.1Climate change may lead to decreased flow in Hawaiis freshwater streamsIncrease in air temperature, amplified at high elevations (Giambelluca 2008)Changes or shifts in annual precipitation Expansion of strawberry guava
USGS has shown a 10% decrease in stream flow over the last 30 years (Oki 2003)
How might these changes impact stream biota?How can we study this impact?
Climate change and Hawaiis freshwater systemsAlright; so it is widely accepted that a changing climate will have impacts on ecosystem function around the globe. In HawaiI, it has been hypothesized that climate change and other factors may lead to decreases in flow. For instance, over the past 30 years the USGS has shown a decrease in stream flow of 10%, with a changing climate as a possible contributor. Additionally air temperatures have been shown to be increasing, with higher elevations showing the most dramatic increases. This may lead to increased evapotranspiration, magnified at these higher elevations. It has also been suggested and is currently being explored that change and shifts in annual preciptation will occur across the Hawaiian island. In addition to these direct effects, the expansion of strawberry guava may lead to lower levels of input to the stream.
The questions that many our concerned with then is how might these changes impact stream biotaand we cannot study the changing climate directly, how can we study its potential impact.2
Space for time: Differences across a precipitation gradient
Unique and extreme gradient in precipitation
Similar landscape and land cover characteristics
Thanks to a the unique geography and climate of Hawaii, studying the potential effects of climate change may be possible by using a space for time substitution. Across the Hamukua coast north of Hilo, there is a strong precipitation gradient across streams with very similar land use and land cover characteristics.. By comparing biotic characteristics within streams with high levels of precipitation to those with low, we may be able to understand how decreased flow may affect stream biota with a limited number of covariables influencing our study. Given that high elevations ecosystems may be most impacted by climate change and that these streams have very similar landscape characteristics, studying a species that generally uses higher elevation systems may be most appropriate. In our case, we chose to focus on the Opae kala ole.
3Why focus on shrimp?Keystone speciesCulturally important Opportunity to gain knowledge on life history
Does variation in annual precipitation alter life history characteristics, abundance and habitat selection?
Opae kalaole in a changing world
Growth rateSecondary productionFecundityHabitat selectionAbundance
hawaii.edu/hsrc/home/timbolsv.htmWhy are we choosing to focus shrimp. First of all, they are a keystone species within high elevations streams in which they spend a large majority of their lives; increasing biodiversity, facilitating leaf litter breakdown, and supplying food for high organisms They are also culturally important in that they were traditionally an important food source for native Hawaiians (and still are). Additionally, there is little documented on life history characteristics of the species within the literature, and this may offer an opportunity to learn more. SO the question we are then attempting to answer is : Does variation in annual precipitation alter life history characteristics abundance and habitat selection of Opae Kala ole?We plan to address this question by sampling growth rate, secondary production, fecundity, habitat selection and abundance in three to six streams across the precipitation gradient during this upcoming summer41. Production and growth rateCapture-mark-recapture2. Fecundity# gravid females and weight3. Abundance/habitat selectionRandom 1 m2 visual estimatesStratified by habitat type
hbs.bishopmuseum.org/waipio/Critter%20pages/atyoida.htmlWe plan on using several methods in order to address this question. First, we will use capture mark recapture to calculate instantaneous growth rate and production of the species. At each site we plan to use baited minnow traps to collect individuals, then tag them individually using VI alphla tags or bin them by tagging with VI elastomer tags.These methods have been shown to be successful in several studies of atyid species in Puerto RicoWe also plan tomeasure fecundity in collected females by counting the total number of gravid females collected and perhaps collecting individual weights as wellFinally, we will address abundance and habitat selection by conducting visiual survery in 1 m2 throughout the stream, stratifying by habitat type.
5Anticipated resultsGrowth rateSecondary productionGravid femalesIndividual fecundity
In streams with less precipitation (i.e. flow):Pool occupancyDensity
hawaii.gov/dlnr/dar/streams_native_animals.htmlWhat we expect to see is that those streams with less preciptation and therefore flow will have decreased growth rates, less secondary production, and a smaller number of gravid females and invidiaul fecundity. In terms of habitat selection, we anticipate an increase in pool occupancy and a overall density as available habitat decreases. Our anticipated results are based on studied on atyid species from several studies exploring growth rates and fecundity before and after drought conditions in Puerto Rico
We hypothesize that limitations on growth rate and secondary production may be related to food limitation from density dependent effects and decreases in downstream particle movement, therefore directly correlated with increase of pool use and decreases in suitable habitat. Our anticipated results are based on studied on atyid species from several studies exploring growth rates and fecundity before and after drought conditions in Puerto Rico
6Benefits and applicationsImmediate applicationsBetter understanding of life history characteristicsInsight into habitat selection of freshwater shrimp throughout the tropicsDefine in-stream flow thresholdsWeb-based management tool
Future directionsUse results and climate change projections to predict distribution and abundance changesExplore relationships between abundance and land cover
In terms of immediate benefits, we believe this stidy will give us a better understanding of life history characteristics of Opae kala ole, while supplying insight into habitat selection of other atyid species throughout the tropics. Additionally, these results will be used to define instream flow thresholds for healthy and productive populations, which will then be built into a larger web based management tool.
We also hope that the results of this research combined with climate change projections may help predict distribution and abundance changes across hawaii. In additional, we also hope to explore have current and perhaps future landcover may impact the abundance of opae kala ole in high elevations, with initial abundance estimates this summer being a jumping off point.7AcknowledgementsDr. Christian Giardina, Dr. Gordon Smith, Dr. Robert Nishimoto, Dr. Greg BrulandTara HolitzkiUSDA Forest ServiceDivision of Aquatic ResourcesHFHP PartnershipUniversity of Hawaii at ManoaKamehameha SchoolsMichigan Sate UniversityUSGS
With that, I would just like to thank all the individuals involved on this project and the larger monitoring project Aryon just spoke on, as well as the wide range in funders and participating groups.