habitat management

Hughes Mountain redux

/ Ted C. MacRae / Leave a comment

Despite the relatively long drive from St. Louis, a healthy group of 15 showed up for this past Monday’s WGNSS Botany Group outing at Hughes Mountain Natural Area; participation no doubt helped out by a spectacular forecast (sunny with highs in the 70s) and near-peak fall colors. Hughes Mountain is situated in the northern portion of the St. Francois Mountains. At its summit is Devil’s Honeycomb—a barren expanse of uniquely fractured Precambrian rhyolite formed by the gradual cooling of magma inside a volcano that was then exposed over 1.5 billion years of erosion. Devil’s Honeycomb is one of Missouri’s geologic wonders, and it’s rocks are among the oldest exposed rocks in all of North America.

Devil’s Honeycomb, summit of Hughes Mountain.

Rocks are not the only items of interest here; the igneous substrate results in acidic conditions that affect the flora in equally interesting ways. This is most pronounced in the igneous “glades” (more properly called xeric igneous prairies) where the soils are too thin and conditions too dry to support the growth of trees, offering refugia for grasses and other herbaceous plants more typical of the western grasslands to persist. Surrounding the glades are dry and dry-mesic upland deciduous forests of oak and hickory featuring a rich shrub layer and open woodland-adapted herbaceous plants.

Beginning on the trail from the parking lot, John Oliver pointed out a stand of tall, now leafless sumacs which nearly everybody (including this author) assumed to be Rhus glabra (smooth sumac) due to their size. In fact, despite their size, they proved to be R. copallinum (winged sumac), with the ID confirmed by a few persisting leaves and their distinctive axial “wings.” John pointed out that an easy winter ID tip for this species is the fruiting structures, which nod distinctively after first frost (those of R. glabra do not).

Post-frost “nodding” seed head of Rhus copallinum (winged sumac).

Ascending the trail through the dry-mesic forest towards the first set of glades, we noted the brilliant colors of small Acer rubrum (red maple) saplings in the understory. When their leaves finally drop, they will be more difficult to distinguish from A. saccharum; however, their rounded rather than elongated buds will still allow differentiation.

Acer rubrum (red maple).

Several of the oaks were examined, with most thinking they were largely Quercus shumardii (Shumard’s oak) and Q. velutina (black oak)—both similar to each other but the latter bearing larger, grayer, pubescent, quadrangular terminal buds. Approaching the glades, Q. marilandica (blackjack oak), Carya texana (black hickory), and Ulmus alata (winged elm) became more abundant, all three much preferring the drier conditions found around the glade margins. An interesting feature of the latter (in addition to the distinctive, corky ridges on the twigs), is the leaves, which are smaller than those of most other elms but tend to grow larger towards the terminus of the twig. They also tend to be much less asymmetrical at their base than other elms.

Ulmus alata (winged elm) showing gradually larger leaves towards the twig terminus.

Very little was left in bloom, but the remnants of recent bloomers were still evident. Solidago petiolaris (downy goldenrod) and Symphyotrichum anomalum (many-rayed aster) were common along the trail and still recognizable, their showy flowers gone and replaced by developing seeds. Hieracium sp. prob. gronovii (beaked hawkweed) was found nestled among mosses perched on a rhyolite shelf, the flowers gone but the leaves still green and distinctively hairy. Hypericum gentianoides (pineweed) was found on the glades proper, most with their stems and leaves turning red but the occasional plant still green enough to allow crushing its stems and enjoying its orange-like fragrance. Bucking the trend, however, was a small patch of Solidago nemoralis (old-field goldenrod), it’s yellow flowers fresh and bright in defiance of the calendar’s call to senescence. A small jumping spider in the genus Phidippus took advantage of the lingering greenery, hiding among the leaves in hopes of finding equally persistent prey.

Hieracium sp. prob. gronovii (beaked hawkweed).
Solidago nemoralis (old-field goldenrod).
Phidippus sp. on Solidago nemoralis (old-field goldenrod).

The benefits of management efforts by the Missouri Department of Conservation in the area’s forests were more evident than ever. Between the first set of glades and the main glades surrounding the summit, a rich shrub layer dominated by Rhus aromatica (fragrant sumac) stretched endlessly under an open woodland of oak and hickory, the latter turning the canopy bright yellow in vivid contrast to the orange and red shrub layer beneath. Such open woodlands were once common in pre-settlement Missouri but are now rare due to the elimination of fire in the landscape and its mediating impacts.

Rhus aromatica (fragrant sumac).

Entering the main glades, the group made their way up towards the summit and Devil’s Honeycomb, while Ted and Sharon stayed back to take a closer look at and photograph a robust colony of Cladonia cristellata (British soldiers) growing under Juniperus virginiana (eastern red-cedar). Lichens, of course, are unique in the world of vegetation in that they are a composite organism—a fusion between a fungus and another organism (usually a green alga or cyanobacterium) capable of producing food via photosynthesis. None of these groups of organisms are considered plants in the modern sense, and, in fact, fungi are more closely related to animals than they are to plants. Nevertheless, the convergence in appearance, habitat, and ecology of lichens with plants puts their study much more in the realm of botany than zoology.

Cladonia cristatella (British soldiers).
Cladonia cristatella (British soldiers).

The group arrived at the summit just in time to enjoy spectacular vistas under crystal blue skies with wisps of clouds and the balmiest temperatures one could possibly hope for in early November.

The group enjoys the view from the summit of Hughes Mountain.
L–R: Ted MacRae, Rich Thoma, Kathie Bildner, Michael Laschober, Tina Cheung, Kathy Thiele, Nancy Mathis, Sharon Lu, Alan Brant, Mark Peters, John Oliver, Larry Lindenberger, Burt Noll, Gwyn Wahlman, Keith Woodyard.

©️ Ted C. MacRae 2021

9th Annual Fall Tiger Beetle Trip: Day 1

/ Ted C. MacRae / 6 Comments

Once again, I have embarked upon my Annual Fall Tiger Beetle Trip, this being the ninth consecutive year that I have done such a trip. Unlike previous editions, however, the quarry on Day 1 (Sept. 15) was not a tiger beetle but a longhorned beetle. Ataxia hubbardi is not uncommon in the eastern and central U.S. and breeds in the living tissues of a variety of herbaceous plants, but especially certain species of Helianthus, Ambrosia, and Silphium in the family Asteraceae. I was hoping to see a distinctive population of this beetle that is associated with prairie dock (Silphium terebinthinaceum) in the dolomite glades just south of St. Louis. This population is interesting because individuals are smaller, darker, and narrower in form than is typical for the species, and I would like very much to get some photographs of the adults, which seem most abundant in the fall, on the tall flower stalks of their host plant.

Victoria Glades Natural Area | Jefferson Co., Missouri

I first discovered the population many years ago—back in the 1980s when I visited one particular glade, Victoria Glades Natural Area, almost weekly over a period of several years. I left Missouri for a few years in the early 1990s but returned in 1995, and during my absence fire was implemented in Victoria Glades and other glades in the area as a management practice for controlling invasion by woody plants (primarily eastern red-cedar, Juniperus virginiana). While the use of fire has certainly done much to restore the glades and improve its floral diversity, it seems more than coincidental that insect abundance and diversity on the glades is only a fraction of what I observed during my pre-burn collecting in the 1980s. There are a number of beetle species that I found at the glade historically that I have not seen now for more than 20 years; one of which is this distinctive population of A. hubbardi.

Prairie dock (Silphium terebinthinaceum) – host for Ataxia hubbardi

The prairie dock plants were at the height of bloom, but the flower stems seemed shorter and the normally large, spatulate basal leaves of the plants generally smaller than typical—perhaps a result of this summer’s severe drought. How such conditions affect the beetles is unknown. The day was also rather cool due to unbroken cloud cover and light drizzle, with temperatures in the low 70s during my visit. I spent the better part of two hours inspecting the stems of every prairie dock plant that I encountered and did not see a single beetle, so it has now been 23 years—almost a quarter century—since I’ve seen this once fairly common species at the glade. Can I prove that fire management has extirpated the beetle? No—populations might have been knocked down by the drought, or maybe the adults hide on cool, cloudy, drizzly days. Still, the pattern is too consistent to ignore, and I become increasingly worried that a special feature of these glades has now been lost.

Ninebark (Physocarpus opulifolius intermedius) – host for Dicerca pugionata

On the other hand, another quite rare beetle that I encountered abundantly at Victoria Glades in the past seems to have rebounded from its long absence—the jewel beetle Dicerca pugionata. This beautiful beetle is associated with the scraggly clumps of ninebark (Physocarpus opulifolius intermedius) that hang on in the moist toe slopes of the glades. I wrote about this species earlier this year after re-discovering it in the glades; however, I couldn’t resist taking a few more photographs of this stunningly gorgeous species. This species also makes its appearance in the fall as well as spring, and in the two hours I spent searching I counted 13 beetles—more than I’ve ever seen on any one day. Interestingly, most of these were associated with a stand of plants in an area at the south end of the glade that I had never searched before and that appears not to have been subjected to fire management (cedar removal has been effected instead with a chain saw). Only a few of the beetles were found in the much more abundant plants growing in the area of the glade I am more familiar with and that has obviously been subjected to repeated burning. It’s not proof, but I’m just saying…

Dicerca pugionata on ninebark branch.

Adult beetles are colored almost precisely the same as the bark of their host plant.

More even lighting in this face shot compared to my previous attempts.

The cool temperatures and light drizzle were not conducive to much other insect activity, but while crossing the small, shallow creek that separates the south end of the glade from the main glade, the biggest male tarantula (Aphonopelma hentzi) that I have ever seen caught my attention as it crossed the creek. Situated only 30 miles south of St. Louis, Victoria Glades must represent the northeastern limit of distribution for the species, and although I once saw a tarantula crossing the road very near to this location, this is the first tarantula that I have actually seen in the glades that lie so close to St. Louis. Males are famous for their fall wanderings, presumably in search of the females that tend to stay within their burrows. This male was missing part of one of its hind legs but otherwise appeared quite healthy and robust. I hope he succeeds in finding a mate and sires many offspring and is not discovered by any of the poachers who regularly scour the glades and steal its more unusual inhabitants—the glades have already lost enough of their unique residents…

Can you find the tarantula crossing the creek? (Hint: 0.60X, 0.37Y)

Male Aphonopelma hentzi | Jefferson Co., Missouri

Copyright © Ted C. MacRae 2012

Flaming the debate

/ Ted C. MacRae / 14 Comments

Eastern redcedar encroaching loess hilltop prairie, a critically imperiled natural community in Missouri.

ResearchBlogging.orgAs my interest in prairie insects has increased over the past few years, so has my interest in their conservation. Many insects are restricted to prairies through dependence upon prairie plants or their unique physical and trophic characteristics. Thus, preservation of not only prairie plants but their insect associates as well is a major goal of conservationists.  The task is daunting – for example only ~1% of tallgrass prairie remains in the central U.S., the rest long ago converted to agriculture or otherwise irreparably altered.  Prairies are dynamic natural communities that rely upon disturbance – this need to “disturb to preserve” creates an oxymoronic conundrum for restoration ecologists that is made even more difficult by the fragmented nature of today’s prairie landscape.  The situation here in Missouri is even more difficult, as nearly all of our grassland preserves (tallgrass prairie, sand prairie, loess hilltop prairie and glades) are exceedingly small and highly disjunct relicts not connected as parts of larger systems.

In recent years, prescribed burning has become the management tactic of choice for restoring and maintaining grassland preserves.  There are good reasons for this – not only are increased floral diversity and reversal of woody encroachment well-documented responses to fire, but burning is also highly cost-effective (a critical consideration in today’s climate of shrinking public budgets).  As the use of prescribed burning on grassland preserves has become widely adopted, however, concerns about the impacts of fire on invertebrate populations have been raised.  The subject is now an area of intense research, but studies are hampered by the limited availability of large, long-unburned tracts of native prairie, and no scientific consensus has yet emerged.  Regrettably, the debate has polarized into “pro-” and “anti-fire” camps that seem unable to communicate with each other constructively.  This is unfortunate, since both ends of the spectrum offer ideas that could be used to achieve the goal of preserving prairie remnants while mitigating concerns about invertebrate impacts.  I have previously expressed my own views on the subject, a position that I suspect some might mistakenly characterize as “anti-fire.”  While I do support the use of prescribed burning, I do not support its use with no consideration of other prairie management strategies such as haying and light grazing (not to be confused with the heavy, abusive, unmanaged kind of grazing that has degraded so much of our landscape).  All of these tools (as well as parcels that receive no management at all) have potential value in prairie management and should be considered.

Those interested in potential fire impacts on prairie invertebrates will be interested in this latest salvo by Scott Swengel and colleagues, who used metadata analysis to correlate declines of prairie butterflies in the Midwest with the widespread adoption of prescribed burning as a management tactic.  The authors present convincing evidence that tallgrass prairie butterfly populations are not co-evolved with fire regimes currently used for prairie management, although their conclusions will no doubt be challenged.  Nevertheless, until a firmer scientific consensus can be achieved, prudence should dictate some measure of caution in the use of fire as an exclusive prairie management tactic.

Dear Colleagues:

We are pleased to announce a new article by Scott Swengel, Dennis Schlicht, Frank Olsen, and Ann Swengel, based on long-term data that has just been published online,  Declines of prairie butterflies in the midwestern USA.  This paper is available free from Springer Open Choice at http://www.springerlink.com/content/l732444592662434/fulltext.pdf or by going to the Journal of  Insect Conservation Online First section and scanning through the articles in ascending number order until getting to articles posted 13 August 2010.

The trends of tallgrass prairie skippers shown here, although disastrous, underestimate the decline in Iowa and Minnesota for several reasons:

  1. In statistical testing we only include sites with adequate data for testing, which eliminates many sites from inclusion that had 100% declines of a specialist we know about.
  2. Nearly all sites with long time series were the top sites to begin with, which are likely to take a longer time to show large declines than medium or low-quality sites.
  3. Recent government sponsored surveys not included here show another round of huge declines for Poweshiek Skipperling in Iowa and Minnesota.
  4. Some species went undetectable by the late 1980s and early 1990s, so didn’t register as a presence when the study began.  Hence, they cannot show a decline since then.

Some good news is that conservation based on existing knowledge of specialists’ management responses gets far better results (as shown by Regal Fritillaries and Karner Blues in Wisconsin than typical management.  So declines like this are not inevitable.

The Ecological Interpretations and Conservation Conclusion section of Discussion contain some of our new insights explaining the observed about land-use effects on prairies and butterflies.

Scott Swengel

My thanks to Scott Swengel for giving me permission to reprint his introduction.

REFERENCE:

Swengel, S. R., D. Schlicht, F. Olsen & A. B. Swengel. 2010. Declines of prairie butterflies in the midwestern USA Journal of Insect Conservation: DOI 10.1007/s10841-010-9323-1.

Copyright © Ted C. MacRae 2010

The joys of ecological restoration

/ jtrager / 11 Comments

Indian paintbrush and lousewort now dominate patches of SNR

I moved to Missouri in the summer of 1988, having experienced 8 years of generous support of my family’s livelihood by my research on the infamous imported fire ants of the US Southeast, and their relatives in South America. When I arrived in the Midwest, I  hoped to land a job as an insect taxonomist in a university or museum, a goal of mine since before entering college. But this dream was one that even before moving to Missouri was dimming, and then receded ever further from the realm of possibility for me (and for traditionally trained taxonomists, generally), once here. So, I began to re-think what I might do with my work life. It would be something, I hoped, that would make some use of all the course work (mostly in entomology and botany) and research (on ant systematics) I had done during my 24 years (!) of getting educated and four additional years as a post-doc. As or more important, whatever job I ended up in would somehow have to allow me to share my life-long love of nature with others.

A museum drawer of ant specimens mounted for taxonomic study, the ants no doubt frustrated by the years of inattention they have received as I have tended to the duties of my day job.

Early in my residence in eastern Missouri, I made the acquaintance of the naturalist at a 2500-acre (1000-hectare) nature reserve outside of St. Louis. Shaw Arboretum, as it was then known, is country cousin to the world-renowned Missouri Botanical Garden, and is named after the Garden’s founder Henry Shaw. Long story short, in the summer of 1990 the naturalist mentioned to me that he would soon retire, the position would become available, and that I ought to apply. So I applied, and was hired as the arboretum’s naturalist in January 1991.

A dolomite glade plant endemic to a few counties in eastern Missouri, this leatherflower was established at SNR in the 1930s, but expanded exponentially after prescribed fire was introduced in the 1990s. Here, an ant characteristic of glades and dry prairies forages on the flower.

When I came on board, the “Arboretum” had mostly ceased to be an arboretum (a formal collection of trees for display, breeding and research), and most folks seemed unable to either pronounce or define the word. Indeed we learned, through a public survey, that the strange name and the stone wall in the front actually dissuaded people unfamiliar with it from entering! Yes, there were a few patches of exotic trees scattered around the property, especially in the conifer collection near the front entrance know as the “Pinetum”, but ever since the Garden had decided around 1930 that it would not, afterall move all of its horticultural operations to this then very rural site (the original intent of its purchase), formal arboretum and botanical garden type activities had been few and far between, and the site began gradually reverting from abandoned farmland to a wilder sort of place, as well as a haven for native biota. Thus, on its 75th anniversary in the year 2000, Shaw Arboretum was renamed Shaw Nature Reserve.

Colony-founding queen bumblebees are the primary actors in loosening pollen with ultrasound from shootingstar anthers, and distributing it about the plant population.

Around that time, my title changed too, to “Restoration Biologist”. The job is multifaceted; presenting public programs and classes on various aspects of the site’s natural history, writing and reviewing articles, acting as liaison to the vigorous regional group of academic ecologists who use the site for research and teaching, a very intermittent personal research program on ants resulting in sporadic publications, and last but certainly not least, ecological restoration.

Ecological restoration, in the broad sense, consists of  two primary practices:

  • Restoration of a natural community to structure and species composition presumed characteristic of an  ;;earlier condition (however arbitrary or ill-defined).
  • Reconstruction of regional, native-like habitats, de novo, using locally acquired native plant propagules in the appropriate settings of soil, hydrology,  slope aspect and climate.

Both  require essentially perpetual, follow-up maintenance, including invasive species control, mowing, haying, grazing, selective timber removal, species richness enhancements, and prescribed burning. All of these have many variations and nuances in application, and there can be impassioned arguments about their implementation in the literature, at conferences, and in forums and blogs on ecological restoration, native plants, butterflies, beetles, etc..

An ecologically conservative lily ally of undisturbed moist soil habitats now thrives in prairie plantings at the Reserve.

Attitudes about ecological restoration vary, among practitioners, among sociologists and philosophers, and in the general public. One broad attitudinal schism lies along the lines of  whether ecological restoration activities are some sort of primitivist, grand-scale gardening, or do they represent ecologically valid landscape conservation? Another question some pose is to what extent we should interfere with “natural successsion”? Be this as it may be, most people with functioning sensory perception agree the results can be very beautiful. The loveliness of the mosaic of colors in the herb layer of a spring woodland is inarguable, especially so after it has had its woody stem density reduced, and had the leaf litter burned off, to allow more light, rain and seeds to the soil surface — even where there is genuine concern about damage to invertebrate assemblages residing in forest duff. A waving meadow of grasses and flowers in a tallgrass prairie planting, intended to replace just a few of the tens of millions of acres of this ecosystem that have succumbed to the plow, has its own grand beauty, though its per-square-meter species density of plant species remains less than half that of a native prairie remnant and it is dominated mainly by habitat-generalist insect species rather than prairie specialists, even after 30 or more years.

A self-introduced grassland ant forages among a thriving, human-introduced population of this wet prairie gentian.

The smaller, daily rewards of restoration, to the practicing ecological restorationist and to those who visit his or her work, are many. Over 20 years, in the opened-up woods, restored glades and prairie and wetland plantings at SNR, I repeatedly have enjoyed the “sudden appearance” and increase in populations of ant species (of course) that I never observed during my early years of working at SNR (then scouring it for purposes of preparing an annotated ant list). The feeling I get upon discovering that a grouping of shooting star, royal catchfly, bunch flower or bottle gentian plants, are in bloom at a site where I spread their seeds five, seven, or even ten years earlier is a bit like that one feels when a child is born. The spontaneous colonization of SNR grassland plantings by prairie ragged orchid never fails to amaze me. Bird, or frog, or katydid and cricket songs in a former crop field or pasture, as the “restored” vegetation fills in and matures, is as pleasing to my ear as it is to my soul.

A few days ago (in early July), the director of the Reserve came to my office asking if I had noticed a purply pink, “possibly orchid” flower growing on a section of a berm (planted with native vegetation) in our 32-acre wetland complex. I had not been in the area recently, but headed right out to see what it was. Joyously, and not a little surprised, I learned that seeds of the purple fringeless orchid, sowed at a location nearby 17 years previously, had washed to this site, taken root, and as terrestrial orchids are wont to do, flowered after so many years!

The black-legged greater meadow katydid thrives in low areas and near bodies of water in SNR

The prairie ragged orchid began to appear in old fields and prairie plantings where prescribed burning occurs at SNR. It has not been seen in fields maintained exclusively by mowing or haying.

The purple fringeless orchid surprised the restorationist and St. Louis area botanists by flowering in the SNR wetland area 17 years after the original sowing.

Copyright © James Trager 2010

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Are we loving our prairies/glades/woodlands to death?

/ Ted C. MacRae / 25 Comments

I had such high hopes for last weekend’s collecting trip – late May is boom time for insects across Missouri, we have had good moisture this spring, and I would be visiting some high-quality natural communities that I had not visited for a long time.  My stated goals (the jewel beetles, Agrilus impexus and A. frosti) were long shots – I knew that and would have been fine coming home without those species (which I did) had the the collecting been otherwise productive (which it was not).  Still, I’ve been doing this for a long time now, and I’ve learned to draw on my accumulated experience when things don’t go as planned to give myself the best shot at turning a bad collecting trip into a decent one when things don’t go as planned.  The itinerary with which I start is rarely the one that I actually follow, and this past weekend was a good example of such.

My first stop was Ha Ha Tonka State Park, one of Missouri’s premier parks, boasting high-quality chert, dolomite, and sandstone savanna interspersed with dolomite glades.  It is on these glades and savannas that I hoped to find Agrilus impexus, or failing that at least collect a nice diversity of other jewel beetles on the oaks and hickories of the savannas and surrounding woodlands.  However, it was with some reservation that I even came here after being told by my colleague at the Department of Natural Resources just 2 days before my trip that 75% of the park’s grasslands and woodlands had been burned within the past two years.  For an insect collector, this is never good news – in all my years of collecting insects, my experience in relatively recently-burned habitats has been consistent: collecting sucks!  I decided, however, to visit Ha Ha Tonka anyway because of the quality of the natural communities it contains, thinking perhaps I might be able to find pockets of unburned habitat supporting good insect populations.  This was not to be. I beat oak after oak in the savannas and woodlands – nothing!  I swept little bluestem and Indian grass in the glades – nothing!  The foliage was lush and green and the savanna and glade landscapes highly diverse – given the time of season the place should have been teeming with insect life, yet it almost seemed sterile. Were it not for a few Chrysobothris quadriimpressa jewel beetle adults that I found attracted to a recently wind-thrown black oak tree, I would not have seen any insects here at all.  It appeared my fears about park-wide depression of insect populations had been realized.  However, not one to waste a visit I decided to explore some of Ha Ha Tonka’s fascinating geological features.  Ha Ha Tonka contains one of Missouri’s best examples of karst geology, with complex structures formed from the collapse of a major cave system.  The Devil’s Promenade is one of the more spectacular examples of such, its horseshoe-shaped cliff representing the former interior walls of a now-collapsed cave.  As dusk approached, the day’s poor insect collecting caused me to abandon my plans to stay here and blacklight for nocturnal beetles.  Instead, I decided to break from the itinerary, drive further west and explore Lichen Glade Natural Area in the morning before heading to the Penn-Sylvania Prairie BioBlitz later that afternoon.

Devils Promenade, Ha Ha Tonka State Park

Lichen Glade Natural Area is a small area owned by The Nature Conservancy that boasts a high-quality sandstone glade surrounded by post oak/black jack oak forest.  My first visit to the area more than 20 years ago was during May, and it was one of the most productive collecting trips I’ve had with a number of Agrilus spp. (including A. frosti) beaten from post oak (Quercus stellata) along the woodland edge.  I didn’t visit again until fall of 2002, when Chris Brown, Rich Thoma and I found claybank tiger beetles (Cicindela limbalis) sunning on the exposed sandstone outcrops, and I made one more visit the following May to beat more insects off of post oak.  The Lichen Glade that I returned to this past weekend was a very different place from when I last visited – the surrounding woodlands had been extensively opened (I would guess within the past few years based on the size of the post oak resprouts), and fire had been used throughout the area.  Anticipation turned to frustration when no amount of beating of the woodland vegetation and sweeping of the glade vegetation turned up beetles in any appreciable numbers (or any insects for that matter) and two hours worth of effort yielded not a single buprestid beetle!

Sandstone glade community, Lichen Glade Natural Area

With resignation, I headed on over to Penn-Sylvania Prairie, where during the introduction to the BioBlitz I learned that nearly half of the 160-acre prairie was burned last December and all of it had been burned within the past few years.  I knew what I was going to find – nothing!  Okay, I shouldn’t say nothing, as there actually were some beetles present.  However, the numbers and diversity were low, with all of the species encountered representing common, widespread species.  Moreover, it was not just beetles – all of the invertebrate group leaders (which included experts on snails, ants, butterflies, and bees) reported low overall abundance and diversity in their groups of interest.  Only the vascular plants – the metric by which the value of prescribed burning is always assessed – showed high diversity, with 300 species of mostly native prairie plants recorded for the site.  It was a fun event, with probably ~75 attendees and a delicious pot luck dinner that evening; however, it would have been more enjoyable had there actually been a nice diversity of insects present to document for the preserve.

My comments may make it seem that I am against the use of prescribed burning.  This is not true – I understand the critical role that fire as a management technique plays in restoring and maintaining examples of Missouri’s historically fire-mediated landscape. Without fire and other processes to mimic natural disturbance factors, most of Missouri’s historical grasslands and woodlands suffer relentless encroachment by woody vegetation. However, the modern landscape is very different from the historical landscape, where fires of unpredictable scale, intensity, and frequency operated within a vastly larger scale to create a shifting mosaic of natural communities in various stages of ecological succession. Such processes cannot be recreated on today’s severely fragmented landscape, where the precious few remaining tracts of native habitat are relatively to extremely small and more often than not separated from each other by vast expanses of homogeneous and “inhospitable” habitat (e.g., agricultural, urbanized, or severely degraded lands).  It is in that context that I have great concerns about how aggressively fire has been used in recent years on our state’s natural areas and the impact this is having on insect populations – specialist and generalist alike.  Fire proponents will point to published studies that show little to no effect by the use of fire for managing small, isolated remnants on specialist insects (see review in Henderson 2010).  However, there are an equal number of studies that suggest such concerns are well-founded (see review in Panzer 2002). A consistent limitation in all of the studies that have been conducted is the lack of very large and long un-burned remnants.  Prescribed burning has been adopted so rapidly and pervasively that there just aren’t any significant un-burned remnants left to properly include as controls in such studies.  As a result, the insect fauna present at a given site at the start of such a study is already skewed towards those species that successfully recolonized the area post-burn.  At a minimum, the data to this point are inconclusive, and certainly the potential for impacts has not been given the consideration it warrants in designing fire-management plans for our own state’s prairies and glades. Furthermore, as rapidly and aggressively as fire has been adopted on our few, small, widely disjuct remnants, the opportunity for proper investigation of those potential effects may be gone.  A particularly egregious example of the lack of consideration being given to prairie invertebrates in designing fire management plans is shown in these photos of Iowa’s Sylvan Runkel State Preserve before and after a late May burn and the impact of that burn on a resident population of Nevada buck moths (Hemileuca nevadensis).

Here in Missouri, as in Iowa, it’s a problem of scale – the landscape is too fragmented and remnants too disjunct to manage based strictly on floristic response.   Populations of generalist insect species will recover, and even specialist species may be able to overcome such management practices if they are widely distributed and sufficiently mobile. But what about conservative species with low vagility, such as the swift tiger beetle (Cylindera celeripes) and our disjunct population of the frosted dromo tiger beetle (Dromochorus pruinina), flightless species restricted in Missouri to the few tiny remnants of loess hilltop prairie in northwestern Missouri and a single 2.5-mile stretch of roadside habitat in west-central Missouri?  Until directly relevant data, gathered here in Missouri, are forthcoming to suggest otherwise, I believe the most judicious use of fire possible should be practiced in restoring and maintaining our grasslands and woodlands.  In-season burns may have been a part of the historical landscape, but their use today has great potential to result in local extirpations and should be used only after the most careful consideration.  Leaving un-burned refugia within remnant habitats to accelerate recovery would also be prudent – yet many land managers disregard this practice because of its logistical difficulties. This is especially true in small parcels, yet it is precisely these remnants that have the most to gain from their use (or lose from not doing so!).  In the historical landscape, every burn was a patch burn – no matter what its size, there were always adjacent or proximal unburned habitat from which recolonization could occur.  Elk and bison, too, were integral components of the presettlement prairie landscape – their roamings caused intermittent, localized disturbances that were likely not only crucial to the tiger beetles that I study but may also have contributed to vegetational diversity through patch succession.  Techniques that mimic these natural disturbance factors include mowing, haying, and managed grazing.  They can be utilized to mimic those disturbances as well as delay woody encroachment, and their use in land management should be considered for their ecological value rather than deprioritized because of their relatively greater complexity and cost to implement. Mechanical removal and selective use of herbicides offer additional tools for addressing woody encroachment while minimizing potential impacts to insect populations. An effective management program that considers all of the flora and fauna of a remnant may not be possible unless all of these management tools are utilized, or at least properly considered. As my good friend James Trager said in a recent email (quoting Andrew Williams), habitat restoration “cannot rest on any single management practice, nor practicing it too extensively.”

REFERENCES:

Henderson, R. A.  2010. Influence of Patch Size, Isolation, and Fire History on Hopper (Homoptera: Auchenorrhyncha) Communities of Eight Wisconsin Prairie Remnants.  Wisconsin Department of Natural Resources, Research Report 189, 22 pp.

Panzer, R. 2002. Compatibility of prescribed burning with the conservation of insects in small, isolated prairie reserves. Conservation Biology, 16(5):1296-1307.

Copyright © Ted C. MacRae 2010

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BitB’s Newest Contributor

/ Ted C. MacRae / 10 Comments

Those of you who have followed this blog for any length of time have likely noticed fairly regular participation in the comments sections by one James C. Trager.  Occasionally irreverent and always articulate, his informed quips are among those that I have enjoyed the most.  One can surmise from James’ comments that he knows a thing or two about entomology himself, but to say this would be an understatement!  Like me, James is a passionate entomologist whose scientific interests take him deep into many related fields of natural history study.  Unlike me, James is a formally trained insect taxonomist, specializing in ants (family Formicidae).  He has conducted numerous biogeographical and systematic studies on this group, much of it in the southeastern U.S. (list of publications), and is the current project leader for the Missouri Ants and Illinois Ants pages at AntWeb.org (whose ambitious goal is to provide information and high quality color images for each of the ~10,000 known ant species).  James’ deep knowledge of this single taxon, however, does not limit his interest in other insects — singing insects in particular are among his favorites. It is, thus, with great pleasure that I introduce James as the newest BitB contributor.

In fact, James and I have known each other for many years, as we are both based in the St. Louis area.  James is a restoration ecologist at Shaw Nature Reserve, a 2,500-acre ecological preserve located in the Ozark foothills (and just 15 miles from my house).  Originally established by the Missouri Botanical Garden for managed plant collections, its recent focus has shifted to environmental education and ecological research, and James has played a key role in their many ongoing wetland, woodland, prairie and glade (xeric limestone prairie) restoration efforts.  This experience combines with his entomological expertise and extensive travel within the U.S. and abroad (e.g., Ecuador) to give him a breadth of knowledge and perspective achieved by few, and I think you will find his writings most enjoyable.  Look for his first post to appear in the next day or so.

Ted & James in restored woodland at Shaw Nature Reserve. Photo by Madison MacRae.

Copyright © Ted C. MacRae 2010

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Florida Scrub Lizard

/ Ted C. MacRae / 18 Comments

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The Florida scrub lizard (Sceloporus woodi) is restricted to isolated sand scrub habitats in peninsular Florida.

Tiger beetles were not the only rare endemic species that I encountered during my visit to the Lake Wales Ridge in central Florida last August.  I didn’t know what this small lizard was as I watched it bolt from the trail and scamper for cover during my approach; however, having already found two endemic tiger beetles, I had a feeling that this lizard might also be a good one.  The photo shown here is admittedly not one of my best, but it was the only one I managed to get before the lizard ducked into the brush for good.  Horribly overexposed, I did what I could with it in Photoshop to make it halfway presentable, but there is no question that its subject represents a Florida scrub lizard, Sceloporus woodi¹.  This small, diurnal, ground-dwelling lizard belongs to the family Phrynosomatidae (same family as the Texas horned lizard that I featured in this post) and is restricted to Florida’s rare sand scrub and sandhill habitats.  Like the recently featured Highlands Tiger Beetle, this species is threatened by the isolated, disjunct nature of its required habitat—a threat made worse by the ever increasing pressures of agricultural conversion and urban development.

¹ Sceloporus is derived from the Greek word scelos meaning “leg” and the Latin word porus meaning “hole”, referring to the pronounced femoral pores found in this genus of lizards. The species epithet honors Nelson R. Wood, a taxidermist at the U.S. National Museum who collected the type specimen in 1912.

Distribution of the Florida scrub lizard (from Branch et al. 2003).

The Florida scrub lizard is related to and closely resembles the much more common and widely distributed southern fence lizard (Sceloporus undatus), which co-occurs with the scrub lizard in northern Florida.  Fence lizards, however, lack the dark brown lateral stripe that is clearly visible in the above photo, a feature seen in juveniles and adults of both sexes of the scrub lizard.  Juvenile and adult female scrub lizards also exhibit a dorsal zigzag pattern; however, this fades in males as they reach adulthood and develop the characteristic bright blue belly patches that are seen in both this species and in the fence lizard (Branch and Hokit 2000).  Since light blue patches are just visible on the belly and throat of the individual in the photograph, I haven’t been able to determine whether it represents a mature female or a still-juvenile male—any help from a knowledgeable reader would be greatly appreciated.  Unlike the fence lizard, the scrub lizard displays a high degree of habitat specificity, occurring as disjunct populations in strict association with the major sand scrub ridges of Florida.  The healthiest populations are found on the Mt. Dora Ridge in northern peninsular Florida, on which significant remnants of scrub habitat are preserved in the Ocala National Forest.  Populations also occur on the Lake Wales Ridge of central Florida and the Atlantic Coastal Ridge, but the status of these populations is less secure.  Populations also once occurred along the southwestern coast on the Gulf Coast Ridge, but these populations are now believed extirpated as a result of urban development (Jackson 1973, Enge et al. 1986).  While the Florida scrub lizard is not listed as a threatened or endangered species at the state or federal level, its high specificity to an increasingly isolated and fragmented habitat and its apparently low dispersal capabilities are clear causes for concern over its long-term prospects. As remnant habitats continue to shrink and become more isolated, the threat of localized extinction becomes an increasing concern for the lizard populations that they support.

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Scrub lizard habitat is threatened by development, fragmentation and increased vegetation.

The precarious status of scrub lizards and their occurrence in several disjunct, isolated populations makes them interesting subjects for genetic studies. Mitochondrial DNA analyses suggest that scrub lizard populations exhibit a high degree of phylogeographical structure, with populations diverging significantly not only between major scrub ridges, but also within them (Branch et al. 2003).  The findings support the notion of long-term isolation of scrub lizard populations on the major scrub ridges and confirm their low dispersal rates among adjacent scrub habitats within ridges (as little as a few hundred yards of “hostile” habitat may be sufficient to prevent movement to adjacent habitats).  More significantly, the results support the concept of two distinct morphotypes on the Mt. Dora and Lake Wales Ridges and also raise the possibility that Atlantic Coastal Ridge populations represent a distinct evolutionary entity as well.  These findings are consistent with the hypothesis that scrub lizards evolved in central Florida, where they were isolated when surrounding lands were inundated by rising sea levels during the late Pliocene and subsequent interglacial periods during the Pleistocene.  During periods of low sea level they dispersed to the younger Atlantic and Gulf Coastal Ridges, where they were isolated from parent populations when more mesic conditions returned during the Holocene (12 kya to present).  The genetic distinctiveness of these different ridge populations may justify qualifying each of them for protection as “significant evolutionary units” under the U.S. Endangered Species Act, since it raises concerns about the use of translocations, a common strategy for establishing new populations in restored habitat or augmenting existing populations, as a conservation strategy for the species as a whole.  Since lizards located on different ridges are more divergent than lizards from populations located on the same ridge, movement of lizards between ridges could compromise the integrity of the genetic differences that have accumulated over millions of years and result in loss of genetic diversity.  As a result, augmenting populations on the Lake Wales and Atlantic Coast Ridges with lizards from robust populations on the Mt. Dora Ridge may not be desirable.  Instead, it may be necessary to protect individual scrub lizard populations on each of the major scrub ridges in order to preserve as much of their genetic diversity as possible.

REFERENCES:

Branch, L. C. and D. G. Hokit. 2000. Florida scrub lizard (Sceloporus woodi). University of Florida, IFAS Extension Service Publication #WEC 139, 3 pp.

Branch, L. C., A.-M. Clark, P. E. Moler and B. W. Bowen.  2003. Fragmented landscapes, habitat specificity, and conservation genetics of three lizards in Florida scrub.  Conservation Genetics 4:199

Enge, K. M., M. M. Bentzien, and H. F. Percival. 1986. Florida scrub lizard status survey. Technical Report No. 26, U.S. Fish and Wildlife Service, Jacksonville, Florida, U.S.A.

Jackson, J. F. 1973. Distribution and population phenetics of the Florida scrub lizard, Sceloporus woodi. Copeia 1973:746–761.

Copyright © Ted C. MacRae 2009

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Highlands Tiger Beetle

/ Ted C. MacRae / 11 Comments

When my wife and I made plans to spend a week at her sister’s condominium in Florida this past summer, I began making a list of the tiger beetle species that I wanted to see.  I would be happy to see anything, since I had never before tiger beetled in Florida, but early August was looking to be on the late side for many things.  In addition, since this was a family vacation, I would only have a couple days at most to sneak off on my own and immerse myself in bug hunting.  All this meant that I would have to be very judicious about where I went and what I looked for.  I sought advice from a few other cicindelophiles on species and localities, and by the time we made the 16-hour drive from St. Louis to Seminole (near St. Petersburg) I had settled on two destinations—the Lake Wales Ridge of central Florida to look for Cicindela highlandensis (Highlands Tiger Beetle), and the so-called “Road to Nowhere” near Steinhatchee where as many as 10 species of tiger beetles can be seen when the season is right.  Things started out well when, before even looking for any of these species, I stumbled upon Ellipsoptera marginata (Margined Tiger Beetle), its sibling species E. hamata lacerata (Gulf Beach Tiger Beetle), and some 3rd-instar larvae in their burrows that proved to be the Florida endemic Tetracha floridana (Florida Metallic Tiger Beetle) in the small coastal preserve just outside the back door of my sister-in-law’s condo.

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Dry sand scrubland on Lakes Wales Ridge in central Florida

The big target of the trip, however, was not so straightforward.  Cicindela highlandensis is one of Florida’s rarest endemic tiger beetles, being restricted entirely to remnant sand scrubland and pine woodland habitats along the Lake Wales Ridge of Polk and Highlands Counties in central Florida (Choate 2003).  The Lake Wales Ridge represents former shorelines deposited when the rest of peninsular Florida was covered by seas.  The quick draining sands have created desert-like open habitats dominated by oaks, pines, and other drought-tolerant species.  Cicindela highlandensis is one of many plants and animals endemic to the Lake Wales Ridge, which has the highest concentration of endangered plants in the continental U.S.  Unfortunately, the natural communities found on the Lake Wales Ridge have suffered severe reductions from their historical occurrence.  An estimated 85% of the scrub and sandhills has been converted to citrus groves and urban developments, and the few remaining tracts face not only continued development pressure, but also the threat of degradation from reductions in the frequency and extent of the wildfires that are essential for their maintenance (Turner et al. 2006).  NatureServe (2009) estimates that C. highlandensis populations have declined by as much as 90%, and only a few of the sites where it is known to occur are large enough to sustain viable populations.  While the species has a global status of G1 (critically imperiled) due to its limited range, restricted habitat, and very small population size, and is a candidate for listing as an endangered species by the U.S. Fish & Wildlife Service (Pearson et al. 2006), it remains—bafflingly—unlisted even as threatened by the State of Florida.  As a result, there is no formal conservation management plan for this species to ensure its survival.  Fortunately, the largest populations of C. highlandensis occur on an assemblage of public and private lands that are under partial to full conservation ownership, and preservation/management activities are taking place at most of these.

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Cicindela highlandensis, Highlands Tiger Beetle, in alert position

I had debated whether to look for Cicindela highlandensis at all—not because I wasn’t anxious to see it, but because I lacked confidence that I would be able find it.  A late season search for a rare species had all the hallmarks of a potential wild goose chase.  Nevertheless, I like a good challenge, and I had succeeded in obtaining information about specific locations for the species (a matter of public record; however, I prefer to maintain some discretion in this venue).  Although I began my search with tempered optimism, it didn’t take long for me to acheive my goal.  Similar to my experience with Cylindera celeripes in Oklahoma, I had barely walked ten yards into a gorgeous sand scrub habitat at the first site I had planned to search before I saw an individual.  The dark metallic blue coloration of the species would seem to make it easily seen in its white sand environs; however, in reality it is almost impossible to see until it moves.  Some have suggested that its coloration functions to make the beetle resemble the many small pieces of debris that litter the sand surface—perhaps the bits of charred wood that are common in open, fire-mediated environments.  Its dependence upon natural disturbance factors such as fire was made apparent to me by the distinct preference I noted for adults to congregate along trails kept open by human disturbance, and to a lesser degree in the larger, naturally open scrub areas.  The adults made very short escape flights and were easy to follow but difficult to approach closely enough for photographs due to extreme wariness—their long legs giving some indication of their highly cursorial capabilities.

Cicindela highlandensis

Cicindela highlandensis - note absence of setae on thorax and abdomen

Cicindela highlandensis is closely related to two other species of tiger beetles in Florida—C. abdominalis (Eastern Pinebarrens Tiger Beetle), widely distributed throughout the Atlantic and Gulf Coastal Plain, and C. scabrosa (Scabrous Tiger Beetle), confined to the Florida Peninsula and adjacent southeastern Georgia.  Both of these species are absent from the Lake Wales Ridge and, thus, do not co-occur with C. highlandensis. It is likely that C. highlandensis evolved from isolated populations of the widespread C. abdominalis that diverged during pre-Pleistocene separation of the Lake Wales Ridge from the mainland (Choate 1984).  Despite its resemblance to both C. abdominalis and C. scabrosa, C. highlandensis can be distinguished from both of those species by the complete absence of flattened, white setae on the sides of the prothorax and the abdomen and by the highly reduced or absent elytral maculations (note the very small apical markings on the individuals in these photographs).  All three of these species belong to the subgenus Cicindelidia (American Tiger Beetles) and possess red adominal coloration that is prominent during flight.

Photo details:
Photo 1: Canon 17-85mm zoom lens on Canon 50D (landscape mode), ISO-100, 1/160 sec, f/13, natural light.
Photos 2–3: Canon 100mm macro lens on Canon 50D (manual mode), ISO-100, 1/250 sec, f/14 (photo 2) or f/20 (photo 3), MT-24EX flash w/ Sto-Fen diffusers.

REFERENCES:

Choate, P. M., Jr.  1984.  A new species of Cicindela Linnaeus (Coleoptera: Cicindelidae) from Florida, and elevation of C. abdominalis scabrosa Shaupp to species level.  Entomological News 95:73–82.

Choate, P. M., Jr. 2003. A Field Guide and Identification Manual for Florida and Eastern U.S. Tiger Beetles.  University Press of Florida, Gainesville, 224 pp.

NatureServe.  2009.  NatureServe Explorer: An online encyclopedia of life [web application].  Version 7.1.  NatureServe, Arlington, Virginia.  Available at: http://www.natureserve.org/explorer (accessed: November 12, 2009).

Pearson, D. L., C. B. Knisley and C. J. Kazilek. 2006. A Field Guide to the Tiger Beetles of the United States and Canada. Oxford University Press, New York, 227 pp.

Turner, W. R., D. S. Wilcove and H. M. Swain.  2006.  State of the scrub: conservation progress, management responsibilities, and land acquisition priorities for imperiled species of Florida’s Lake Wales Ridge.  Archbold Biological Station, Lake Placid, Florida, iii + 44 pp.

Copyright © Ted C. MacRae 2009

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