Project: Salinity Concentration Monitoring of Fresh Water Holes in the Florida Keys.

Interim Report #1: 4/28/2019

Approaching the first month of conducting this project, we are releasing a brief summary of the start-up conditions encountered:

Compared to this time last year, Keys’ wildlife is in much better shape drinking-water wise…with a few exceptions. Referring to our 4/11/2018 report (find it under the “News” tab), mid-April last year had only 2 out of 19 sites on Big Pine Key we informally looked at with salinities below 15ppt, and a single (very dingy) site on No Name that was holding at 6.4ppt. Last year’s dry season was one of the driest in recorded history for Southern Florida and the Keys – hence the abysmal numbers. This year has so far been much kinder to the animals (and plants). Since this project officially started, we have had two significant rain events in April, primarily on the 9th and 19-20th. Data from rain gauges we managed to install before these events underscore how vastly different rainfall can be at different waterhole locations in the Keys: on the 9th, Long Beach Rd. at the southern end of BPK received the same amount of rain as mid-BPK. During the 19th event, Long Beach received only half of what mid-BPK got. We are extremely happy to report that SOKD has initiated a cooperation with the Florida Keys Mosquito Control group who have rain gauges in many places of our study area, and they agreed to share their data for this project. So the newly uploaded salinity and rain gauge location maps include approximate (to safeguard their gauges) locations of some of their gauges as well.

All monitored islands have, at present, multiple sources of wildlife-accessible fresh water with salinities in the single digits – with 3 exceptions, and one island of concern. More importantly, these palatable sources are spatially spread through each island so local deer have local sources. The exceptions are:

1)  BPK Long Beach Road and Refuge land northward along US-1: Since Irma, this area has had no palatable water. The multiple ponds in the forested area have either dried out or act as salt sinks after each rain, only concentrating salt from the surrounding ground runoff…to the point their salinity concentrations exceed 3X seawater. Red algae that thrive in such super-saline conditions are blooming in these ponds and can even be seen from high resolution satellite images. Ponds on private property along Long Beach Rd. show salinities in the seawater range. Hence, any wildlife in this area likely continues to be dependent on human-related water sources. The hammock area between US-1 and Long Beach has recovered greatly from the plant side, but will take years to support any mammal life on a regular basis.

2)  Big Munson Island: Owned by the US Boy Scouts, a recent survey by SOKD found ample fresh signs of deer (6-8+ estimated, which agrees with post-Irma survival estimates). All ponds known and tested were above palatability levels – similar to Long Beach’s problem, although not as severe (ppts in the 30-40s). A single very small solution contained palatable water from the latest rain – 4.32ppt, however, it will likely dry out in the next couple of weeks.

 3) Ramrod Key: As of today, Ramrod has no natural, palatable wildlife drinking water that we are aware of. The (few) deer there may be dependent on man-made/maintained ponds (of which we know 1).
4) Cudjoe Key: This key is a mystery to us, since our scouting of it for drinkable water found only one source directly next to US-1 that is likely way out of territory for the deer that live on this island – some of which were transported here in the early 2000s. We welcome any comments from residents about how this population is finding water.

All comments/suggestions are greatly appreciated! SOKD Board

P.O. Box 431303, Big Pine Key, FL 33043 http://www.saveourkeydeer.org