[LTER-luq] Connection info for monthly meeting

[Jess Zimmerman]

Hi  All,

Another item for the Monthly Meeting.

jess


Jess K. Zimmerman
Professor
Lead PI, Luquillo LTER Program
Director, El Verde Field Station
Department Environmental Sciences
University of Puerto Rico - Rio Piedras
Rio Piedras, Puerto Rico

Tel: 787-764-0000 ext. 1-XXXX-# where XXXX is:
   LTER Program Office: 88233
   El Verde Field Station: 83467
Mobile: 787-380-3311

On Wed, Feb 15, 2017 at 9:12 AM, Sarah Stankavich <sarahstankavich at gmail.com
> wrote:

> *Hypothesis 6*. Increased frequency of intense hurricanes could result in
> higher-elevation streams shifting
> from consumer-controlled to producer-controlled ecosystems, due to the
> increase in stream nutrient
> concentrations, litter inputs, and light inputs that re-configure
> terrestrial-aquatic linkages in these
> headwater streams and riparian forests. (Pringle, Covich, Crowl, McDowell,
> Ortiz, Ramirez)
>
> *Background* – Twenty years of research on stream chemistry and biology
> shows that there is a strong
> response to hurricanes, which alter the riparian forest-stream
> connections, increase some nutrients, and
> change food web dynamics for months to years (Brokaw et al. 2012, Crowl et
> al. 2012, McDowell et al.
> 2013). After hurricanes, nitrate concentrations remain elevated for 18
> months or more (McDowell et al.
> 2013), large litter inputs enter the stream but are rapidly decomposed
> (Crowl et al. 2001, Beard et al.
> 2005), and light levels increase because of increased canopy openness. In
> many ways, the Luquillo
> Mountain streams have been very resilient in response to the past two
> major hurricanes.
> 23
> Increased frequency of intense storms is likely to have profound effects
> on stream communities, bidirectional
> subsidy exchanges, and biogeochemistry. Shifts in riparian vegetation
> toward more shade
> intolerant trees will alter both the transient light regime (more frequent
> periods of high light due to
> repeated hurricane disturbance) as well as the baseline light regime
> (lower LAI with more drought-tolerant
> species), and the quality, quantity, and timing of leaf-litter inputs. We
> will focus on species that are most
> likely to enter or leave the riparian forest community (Hypothesis 4) and
> their effects on subsidy
> dynamics. Following Hurricane Hugo, we observed a 1 kg/m2 input of
> detrital material across the forest
> including the streams (Lodge et al. 1991). We experimentally demonstrated
> that this input resulted in an
> increase in dissolved C, N, and particulate C production and export (Crowl
> et al. 2001).
> In the longer term, we expect that our relatively unproductive
> communities, limited by light and predation,
> will switch from being consumer controlled to being producer controlled,
> resulting in increased microbial,
> algal, insect and decapod and fish densities, total biomass and secondary
> production, as a consequence
> of increased nutrients, allochthonous inputs, and light. In addition, the
> increased inputs of coarse woody
> debris and palm fronds will result in a significant increase in debris
> dams, leaf-litter storage, and habitat
> heterogeneity. This increased habitat complexity will most likely result
> in more spatial refugia for prey
> species and decreased predation by larger consumers (Macrobrachium spp)
> resulting in a decrease in
> top-down control on insects and smaller shrimp species. Taken in
> aggregate, we hypothesize that the
> increased frequency of severe storms in the LEF will fundamentally alter
> the stream ecosystems,
> resulting in increased primary productivity, standing stock biomass, and
> tighter nutrient cycling during
> extended periods between less-frequent, high-discharge events.
>
> *Work plan* – We will enhance our existing stream monitoring to include
> monthly litter inputs, light and
> light gap measurements and microbial responses. In addition, nutrients,
> algal standing crop as well as
> insect, decapod, and fish densities and biomass will be sampled twice a
> year in six headwater streams
> (four of which are currently sampled as LTER focal streams; two additional
> higher-elevation streams).
> Sampling periods will include during the driest time of the year
> (Feb-March) and the period of the most
> severe storms (late September) to capture the effects of dry periods on
> stream biota. Sampling methods
> will follow protocols from our long term measurements (Section 3.1) and
> already established within the
> LUQ framework. Light gaps, coarse woody debris, and leaf-litter inputs
> will be mapped and quantified in
> replicate 100 m reaches in the study streams.
> We will simulate hurricane impacts on the riparian vegetation using the
> SORTIE and Demographics
> models already parameterized for the LEF. Simulations will be used to
> model both short-term (annual) as
> well as long-term (decadal) impacts on riparian canopy composition and
> structure. These simulation
> results will guide future experimental manipulations of riparian canopy
> cover and increased light on the
> stream ecosystem components. Our future goals (LUQ VI) are to conduct a
> canopy trimming experiment
> for streams using a similar design as the CTE. We will explore the
> separate and combined drought
> (stream-water diversion, SDE) and hurricane disturbance through direct
> manipulations and modeling.
>
> On Wed, Feb 15, 2017 at 8:38 AM, Maria Uriarte <mu2126 at columbia.edu>
> wrote:
>
>> Hi Sarah
>>
>> Can u pls send us hypothesis 6?
>>
>> Thanks Maria
>>
>> Sent from my iPhone
>>
>> On Feb 15, 2017, at 6:40 AM, Sarah Stankavich <sarahstankavich at gmail.com>
>> wrote:
>>
>> Hi all - The monthly meeting today at 2 pm EST, 3 pm AST will focus on
>> hypothesis 6. Connection info below
>>
>> LUQ monthly meeting
>>
>> Please join my meeting from your computer, tablet or smartphone.
>> https://global.gotomeeting.com/join/363744021
>>
>> You can also dial in using your phone.
>> United States: +1 (408) 650-3123 <(408)%20650-3123>
>>
>> Access Code: 363-744-021
>>
>> First GoToMeeting? Try a test session: http://help.citrix.com/getready
>>
>> --
>> Sarah Stankavich
>> LUQ-LTER Coordinator
>> El Verde Field Station, Puerto Rico
>> 787-764-0000 ext. 83466 <(787)%20764-0000> (office)
>> 787-222-7756 <(787)%20222-7756> (cell)
>>
>> _______________________________________________
>> Long Term Ecological Research Network
>> luq mailing list
>> luq at lternet.edu
>>
>>
>
>
> --
> Sarah Stankavich
> LUQ-LTER Coordinator
> El Verde Field Station, Puerto Rico
> 787-764-0000 ext. 83466 <(787)%20764-0000> (office)
> 787-222-7756 <(787)%20222-7756> (cell)
>
> _______________________________________________
> Long Term Ecological Research Network
> luq mailing list
> luq at lternet.edu
>
>
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