Wednesday, June 30, 2010

Alligators in Virginia.....The Science!

Gator habitat? Let's find out!

Dream of being a habitat ecologist?! Then get used to doing math!
(8-8-11) - Note to readers: Click HERE for more detailed analysis on where in the Tidewater area that alligators might move in and not be forcibly moved out in the next decade or so......

So, I've been following my web traffic with my little buddy Sitemeter. I've seen some interesting trends develop over just the last month or two since I installed it. The most unexpected has been the volume in web traffic I receive from people searching for "alligators in Virginia" and finding my first post on the topic. Since apparently this is a hot topic among internet users (who knew?) I thought I'd look into the topic a little further (as I've been meaning to do for over a decade). Remember that I mentioned the USFWS Habitat Suitability Index Model for Alligators? Well, I downloaded it, read it, and figured out the model. It's an interesting one. The results are in the excel worksheet above, but what fun is that? Here's what I learned....
First of all, as I sort of mentioned before, we have to blissfully ignore and/or accept three admissions made by the creators of this habitat model. First, though I suspect they were tasked by USFWS to create this model for the entire country, the authors created a habitat model only for the northern Gulf of Mexico (TX, MS, LA, FL panhandle). Second, a lot of geographic assumptions in their text are based on a 1958 field guide to reptiles and amphibians. That's more embarassing than the first thing, for sure. Third, the authors admit (I missed this on my first read) that they never actually field tested the model. And as a habitat ecologist, I can say that that's incredibly pathetic. But you know what? It's better than my model, because I don't have one.
So I entered all of their variables for these sites into their mathematical model for 15 sites near the NC/VA border where alligators are not recognized to exist naturally, 2 sites in NC where they are recognized to be reproducing successfully, and 1 site on the Gulf in TX that is supposedly renowned for its gator population. I did not use 5 sites out of the 18 because once I started working with the HSI model, it was clear that they would score very poorly. As the authors of the HSI recommended, I did my analysis of each habitat "factor" through a combination of memory of some of these areas, photographs I could find, and aerial photos (I used Google Earth). So, are there gator-compatible habitats in Virginia, based on a mathematical model created by the USFWS, who propose that alligators do not live in Virginia?
Absolutely. But I was surprised by the results. You'll recall (links above) that the two closest reproducing populations are at Alligator River NWR (on Albemarle Sound, 60 miles south of the VA border) and Merchant Millpond State Park (in the inland forested swamps, less than 25 miles south of the VA border, with gators occasionally - and officially - spotted within 12 miles of the border at Dismal Swamp State Park).
So what? Well, according to the HSI scores (see below), the highest quality alligator habitats near the VA-NC border are where Back Bay meets the Currituck Sound.....60 miles north of Alligator River NWR. Inland, this is not true, as marginal, patchy habitat occurs just over the VA line within the Dismal Swamp. This probably goes a long way toward explaining why alligators have not moved north faster. A pretty basic conclusion is this: Alligators expanding northward on the coastal sounds are likely to settle on other territories far south of the VA line - they need to go no further. Alligators expanding northward in the interior swamps are likely to find low-quality habitat, and any net progress northward is haphazard.

The HSI scores backed up my analysis...the three reference sites (known gator habitat) scored between 0.57 and 0.75 (out of a possible 1.00 for optimal habitat). 6 out of 7 sites in the far-flung coastal area of Virginia Beach & Chesapeake met or exceeded that range. 0 out of 4 sites in the much closer interior flooded swamp (and rivers like the Nottoway) met that range, although 3 sites were close.
A marketing analogy is easy - would you be more likely to drive 1 mile for a cheap, grizzly hamburger, or an unknown but longer distance to get a delicious steak dinner, cooked just the way you like it? That's exactly the type of decision that sub-adult male alligators are having to make when they get kicked out of their territory and consider a swim north.
I'll polish up this analysis soon with some final predictions for where-exactly, and when-approximately, I believe alligators are likely to first naturally settle and reproduce in Virginia. As a teaser, here are the habitat suitability rankings of the wetlands I analyzed (this is assuming that alligators were air dropped on each site at the same time). Remember that I omitted 99% of the actual area of southeastern VA, concentrating only on "reasonably possible" habitats. These all represent marginal (ranks 14-8), good (ranks 7-2) , or near-optimal (#1) habitat.
19 - 15 Omitted
14. Impoundment at Cavalier WMA
13. Great Dismal Swamp @ Dismal Road
12. Mackay NWR Impoundments (NC)
11. Great Dismal Swamp (Lake Drummond)
10. Camp Mill Impoundments
9. Great Dismal Swamp (NC) (Existing gators - Reference Site)
8. North Landing River - lower reach
7. Aransas NWR Sloughs (TX) (Reference Site)
6. Northwest River - Hog Island (NC)
5. Northwest River - Irrigation Ponds
4. Merchants Millpond (NC) (Reference Site)
2. Ponds & marshes along the Albemarle & Chesapeake Canal
2. Large stormwater ponds along West Neck Ditch
and the #1 ranked site is......
#1 - Knotts Island Causeway, marsh ponds, and impoundment. If alligators establish here, they will easily migrate up into, and through, Back Bay.

Later Alligators!

Wednesday, June 23, 2010

102 Degrees Already?

My Sky-Net style e-traffic robot tells me that you all loved the last bee balm picture, so here's another, now in bloom: Bee Balm var. Jakob Kline. The bees have been abusing it!
In late May, we were 1" above average for rainfall. Barely 4 weeks later, we are nearly 1" below average. Air temperatures have consistently been in the mid-90s (and topped 100 today), with 70-90% humidity almost every day. With air quality warnings in the Northeast (and a 9-month old baby/toddler in my care), it's been an unexpected stay inside for the last few weeks. The good news is that if you water your plants, they sure do grow in this heat and humidity! Check out my garden plot today (below), vs. just a week ago.

We are eatin' some produce now!!!
I've also had the chance to get out and explore some previously restored wetlands (part of my day job), which have ranged from relatively urban stormwater treatment wetlands, to restored bogs, to restored seasonal wetlands on agricultural lands. Unless the weather breaks, I'll be following up this post with a post about those restored wetlands....but here are a few shots...
5-year old restored wetland, designed to treat stormwater in Annapolis, Md. Project was a partnership between the Chesapeake Bay Trust and the South River Federation
Blue Dasher dragonfly perched on an intentionally placed log in a restored bog
Bullfrog hanging out in a dense stand of Parrotfeather about 10 feet away from the dragonflies. Coincidence? Unlikely. 5 minutes later, we saw a 48" water snake inhale a mature bullfrog. Ahhh, life.

Thanks for stopping by!

Wednesday, June 16, 2010

A Quick Stroll Around the Garden

My first year growing Bee Balm var. Pink photoshop editing!
This time of year, it's easy to find beauty in the natural world. Here are a few shots from around the house and garden. Hope everyone's enjoying the outdoors!!! And come on, is that bee balm pink OR WHAT?!

Chive flower (yes, chives!)
The garden plot, mid-June
In the garden, spring greens are starting to get thick! Chives and garlic are basically done, spinach, leaf lettuce, and carrots are growing their hearts out, and the summer vegetables are off to a good start, except for the cucumbers, which all died. We are having a few problems with cutworms (not since I applied Bt!) and slugs (yes, still) but otherwise the pests haven't been bad. I have heard tales of a yearly whitefly infestation at our "farm," and I am not looking forward to that. Check out the garden 20, 60, and 90 days ago!

Dame's Rocket, a European wildflower from a mix I planted in 2009

Black and Yellow Mud Dauber attacking Fall Webworm.
I've also noticed around the yard and garden that a lot of different wasps have been cruising low, right above the ground, and working over the same areas for hours at a time. It finally occured to me that the wasps have all probably laid eggs, and are now hoarding food for their little wasp children (I'm told that's the technical terminology). I'm not totally convinced of the ID of this critter, especially since the "most likely" two species' larvae feed on insects that are not caterpillars (grasshoppers for one species and spiders for another). Regardless, this is a display of behavior similar to that of the the Cicada Killer, which I was fortunate enough to document last summer.

Don't stop, just get it, get it!

Wednesday, June 9, 2010

Fishing Northeastern Maryland at the Intersection of Good Luck, Good Planning, and Perfect Weather

I really wanted a better photo of this hog, but he was tough to hold onto, and ultimately I wanted him to go home unharmed!
Once again, work took me up into the northeastern corner of Maryland. My last trip up here was a really fun one as I was able to get in a few casts before a long day of work travel. There were a lot of variables, including a "late" start (in fishing terms...left the house at 7am), a serious cold front moving through the same morning, and the fact that it's now post-spawn for bass in our area. I really had no idea how it would go, but I figured it was worth a try.
Another nice largemouth caught on light tackle
As I sped northeast up the highway, with the storm bearing down on me from the southwest, I tried to make peace with the fact that this could be an awful trip - from bad weather, to spawn-related "weirdness" with fish feeding patterns, to - worst of all - more people fishing the area due to our recent warm weather.....I had no idea what would happen.
As usual, I started by "indicator fishing" with ultralight tackle (the Pflueger UL Razor Tip is a charm!). Empty first cast, UL lure disfigured by large sunfish (missed the hook) on second cast, 11" largemouth on 4th cast. Time to move to bigger gear.
For reasons I'm too emotional to discuss ("snap!"), I am no longer fishing my famed BPS Wally Marshall Light Spinning Rod. Man, I caught a lot of nice fish on that rod. I have actually moved a step up to the BPS Micro-Lite Rod (Light/Fast Action) and using the same Okuma Avenger reel that I used on the Wally Marshall. I have mixed feelings about the new rod so far. It's extremely sensitive on the strike (which is good) but during fish retrieval, the rod feels really "dead," and I couldn't tell much difference between the biggest fish I caught (first picture in this post) and some of the larger bluegills. In fact, when I got the big guy to the surface, I was not prepared to deal with him - I was just thinking, "get him over land! Get him over land!" And "Sweet! 3 pounder!"
For the first 30 minutes of fishing, I mixed up different sizes and colors of Yo-Zuri Pin Minnows (all 1.6" to 2"). The big boy at the top of this post was caught on the black and silver pin minnow. Other nice fish were caught on the green/white and the black/blue/silver.
I took a stab at other hard baits, including the "Ghost Walk X-Rap" (see below), and had some success. The rain appeared after about an hour, and as the sun came over the trees, the bite slowed down quite a bit. I threw some soft plastics out with pretty minimal results.

This fish looks small until you realize the lure is a 4" X-Rap
Ultimately, in 2 hours I caught about 9 or 10 bass and maybe 8 large pumpkinseed and bluegills. Compared to my last visit to this site, when I caught (I recall) 6 bass and 18? bluegills in 90 minutes. I think the change is a result of my restricting myself to using larger lures and staying away from visible schools of small sunfish. And of course, the falling barometer during this fishing adventure did not hurt one bit!

The water was stained from the vegetation and maybe even from some runoff, so just for fun, I took a page out of Tugboatdude's fishing manual and threw a black inline spinner out there. It worked, ha ha!

Wednesday, June 2, 2010

The Baltimore Community Garden Experiment (#2)

....Baby not included in this package
So I guess I am 8 or 10 weeks into my experiment, which is essentially to find out if someone of moderate gardening talent (me) can successfully grow reasonable amounts of food in a community garden setting - where the individual gardener has no control over (long term) soil conditions, pest control used (or not used) by gardeners less than 36 inches away, or even the other gardeners' attention to their own crops. My observations, it should be noted, are based on my growing (ha ha) experience with the City Farm Community Garden Program of Baltimore, Maryland. We started fairly recently, here. My observations so far have been different than I expected, but first, it's hard to argue with results, so compare the photo above to my starting conditions in April of this year (below).
Wow, that is just plain sad.
First, the demographics of my particular garden differ from other gardens in the City (or so I'm told, upon asking around). Out of 90+ garden plots, there are about 50 gardeners. 49 out of 50 are men. 48 out of 50 are over the age of 60. Most are fully retired. Most are black. Many gardeners picked up "extra" abandoned plots during the 1990s, when community gardening was not a popular idea (at least in Baltimore), so several folks have pretty expansive gardens as a result (how much lettuce can a man eat?). A few seem to have extensive wildflower and herb garden "set-asides" and I am interested in seeing how they develop.
The City Farm program is run, I think, by young idealists who understand the idea of sustainable urban agriculture and local food. This makes me very happy. However, because of the demographics of these gardens (at least mine), there seems to be a disconnect of information and practices - let me use two quick examples.
The City Farm Program Guide explicitly discourages the use of conventional pesticides and herbicides. This makes plenty of sense, on sites where every garden is adjacent to at least 3 other gardens. So imagine my surprise when, on the first warm day of late April, I saw 3 gardeners scooping out piles of systemic insecticide onto open ground on their garden plots. One gardener was so kind as to leave a half-full bag of Sevindust out for other gardeners to use. Given my interest in bees and wildlife, and my own use of Bt, this was a big let down. Honestly though, old guys do it the way they've always done it. How do you change that behavior?
Second example, the City Farm Guide mentions "cover crops" but also has very explicit language about keeping garden plots "free of weeds." For the advanced gardener, this probably seems clear, but clearly most gardeners just practice "clean farming" and forget about "cover crops," whatever that means (I can hear an old timer saying it). This means that at the end of the summer, every ounce of organic matter is removed from the soil, which is then left bare all winter. The effect is that after 20 years of gardening this 5 acre (or so) site, the soil elevation of the garden plots is anywhere from 6 to 18 inches lower than the surrounding turf/clover borders. All that erosion, all that sediment......right to the Chesapeake Bay. I think the City Farm staff should be far more aggressive with encouraging cover crops and other soil conservation methods (like maybe a sediment basin at the lowest end of our site). I'm not sure they are aware of the extent to which many of their gardeners "don't get it."
Another unexpected, and positive, observation I've had is the reinforcement of my theory that the outdoors can bring out the best in people. When our "farm rabbit" ate my lettuce, another gardener said I could take as much of his as I wanted. Almost daily now, other gardeners leave extra seedlings in the shade, labeled for a stranger to take and grow. I've seen gardeners help each other with menial tasks, and I know that I keep watering my "neighbor's" plot, because he visits infrequently and for some reason, I don't want his plants to die. I've never even met him - although someone told me that "he" is a "him," that's all I know about the guy. I haven't heard a single comment about my age (I'm certain I'm the youngest) or my whiteness (I'm not the whitest, ha ha), and honestly, I didn't know if I'd be able to make those statements when I started a few months ago.
The harvest so far has been slim, but things are starting to turn. I'll let you know what happens next!

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Over 12 years ago, I started this blog. There were very few conservation or outdoor blogs at the time, few websites with fast-breaking con...