The stoneflies (Insecta, Plecoptera) of the Talladega Mountain region, Alabama, USA: distribution, elevation, endemism, and rarity patterns

Abstract Background The Talladega Mountain region of eastern Alabama is the southernmost outlier of the ancient Appalachian Mountains, including the highest peaks and ranges in the state. Collections of stoneflies (Plecoptera) previously here have been sporadic yet has led to several new species descriptions in modern times (James 1974, James 1976, Stark and Szczytko 1976, Kondratieff and Kirchner 1996, Szczytko and Kondratieff 2015) and expanded our understanding of southeastern US stoneflies. During the period 2003–2012 we conducted an intensive inventory of the stonefly fauna of the Talladega Mountain region. We collected across all months from 192 unique localities, covering a broad range of stream sizes and elevation gradients present in the region. New information A total of 57 confirmed species across eight of the nine Nearctic families were collected as adults (Table 4), including four species described as new during the study period (Table 2). Leuctra crossi James, 1974 was easily the most common species collected. Median elevations per species ranged from 174 m (Clioperla clio (Newman, 1839)) to 410 m (Leuctra triloba Claassen, 1923 (Fig. 3). Dot distribution maps were included for all 57 species plus one for undetermined nymphs of Pteronarcys Newman, 1838 (Figs. 4–19). As many as seven species may be endemic to the region but sampling efforts northeastward into Georgia, plus additional focused sampling in Alabama and a comprehensive examination of all available material held in museums and personal collections, are needed for confirmation.

Stoneflies are aquatic insects that are sensitive indicators of habitat and water quality conditions (Stewart and Stark 2002). Master et al. (2000) listed stoneflies as the third most imperiled biotic group across aquatic and terrestrial systems in the United States. There is ample evidence that several midwestern USA states have experienced extirpation of their native stonefly fauna since the 1950s. For example, 18 (25% of the state's native fauna) and 10 (12%) species are considered extirpated from Illinois and Indiana, respectively (DeWalt and Grubbs 2011). Extirpation is not unique to North America. In Europe, large river species have disappeared due to organic enrichment and decreases in dissolved oxygen levels (Zwick 1992,Bojkova et al. 2012).
Climate change is affecting biological systems globally both in aquatic and terrestrial habitats (Walther 2010). Mountain ranges are particularly vulnerable due to the influence of "summit traps", especially in low-elevation montane systems (Sauer et al. 2011, Sheldon and. Stoneflies include several cold-stenothermal taxa (Zwick 2000) whose distributions are restricted to montane, high latitude, or spring-fed systems. Consequently, cold stenotherms are considered highly vulnerable to climate warming (Tierno de Figueroa et al. 2010). For example, two stoneflies endemic to the Waterton-Glacier International Peace Park (Alberta, Canada and Montana, USA), Lednia tumana (Ricker, 1952) and Zapada glacier (Baumann and Gaufin, 1971), have experienced reductions in range and genetic diversity with concomitant loss of glaciers and snowfields (Giersch et al. 2015, Jordan et al. 2016).
Natural areas (e.g. nature reserves, national parks) are widespread throughout the US and have the potential to conserve ecosystems and native fauna and flora (Jenkins et al. 2015). Unfortunately, the task of providing biotic protection is not always realized (Venter et al. 2014) despite the fact that distributional data is increasingly more accessible to land managers (Pimm et al. 2014). Focused surveys and monitoring programs have the capacity to increase our understanding of how protected areas support and protect regional species pools.
Our overall objective of this study was to thoroughly inventory the stonefly fauna of a significant focal area, the Talladega Mountain region (eastern Alabama, USA), by collecting across months and years from multiple localities representative of the broad range of stream sizes and elevation gradients. We intended these data to useful in conservation and land management applications, adequate for ecological, systematic and biogeographic analyses, and a firm basis for designing subsequent research on the ecology of stoneflies of this interesting region.

What is the Talladega Mountain region?
The Talladega Mountain region, as the southernmost outlier of the ancient Appalachian Mountains, represents a unique location in the biological and landscape diversity of the southeastern USA (Duncan 2013). This region consists of metamorphic and igneous rocks and is a composite of several low-lying ridges and other uplifted regions and adjacent valleys in the Piedmont plus Ridge and Valley Physiographic Provinces in eastern Alabama ( Fig. 1). For convenience, The Talladega Mountain region can be dissected into "southern" and "northern" sections by Highway Interstate 20 (I-20; Fig. 1).
Starting southward in the Piedmont Physiographic Province, Talladega Mountain in a broad sense is a composite of several long and narrow ridges that include Rebecca Mountain, Horn Mountain, and Cheaha Mountain (= high point in Alabama, 734 m/2407 ft), plus several other high peaks (e.g. Odum Point, 714 m/2342 ft) within the region (Fig. 1). These ridges are defined by erosion resistant metamorphic rock (Cheaha Quartzite) and bordered by terrain of moderate relief on softer Lay Dam Formation (Geological Survey of Alabama 1988). The exposed quartzite ends beyond Cheaha Mountain and the mountainous region continue north of Highway I-20 as an uplifted region that includes Brymer Mountain (442 m/1450 ft) and Rattlesnake Mountain (509 m/1670 ft). The region contacts sedimentary rocks of the Valley and Ridge Province northward along County Route 55. The dominant formation in the northern portion of the region is the Weisner Ridge Sandstone and some Shady Dolomite, reaching 652 m (2140 ft) at Dugger Mountain. Located immediately west and extending southward towards Highway I-20 is Choccolocco Mountain, the other prominent Ridge and Valley structure in this region. Choccolocco Mountain peaks at 629 m (2063 ft) and is also part of the Weisner Ridges with outcroppings of Weisner Quartzite.
The regional climate is highly variable and characterized by hot summers, cool winters, and moderate rainfall. The period extending from August-October is a dry season. Heflin, AL  All unique collection localities (n = 192) in this study and the locations of the larger streams and rivers in the region.
Streams are numerous and the entire region is nested within the Coosa River Basin. Upland streams drain northward to Terrapin Creek, eastward into the Tallapoosa River, southward into Lake Martin, or westward directly to the Coosa River (Fig. 2). Most upland streams are unregulated but three impoundments influence upper Shoal Creek and there is a small impoundment in the Dry Creek headwaters within Cheaha State Park. Larger regional streams support diverse assemblages of fishes, mussels, and snails, including several species of conservation concern (Boschung and O'Neil 1981, Mirarchi et al. 2004, Meade et al. 2009, Edelman et al. 2015. Forest composition varies from diverse bottomland hardwood forests, including some loblolly pine (Pinus taeda L.), to pine-dominated (shortleaf pine P. echinata Mill., longleaf pine P. palustris Mill., and Virginia pine P. virginiana Mill.) forests with several species of oak (Quercus L.) at higher elevations and on drier sites (Shankman andWills Jr. 1995, Womack andCarter 2011). Establishment of loblolly pine plantations and restoration of longleaf pine savannas (Duncan 2013) continue to alter the forest landscape. Much of the range is publically owned and managed by the Talladega National Forest (Talladega and Shoal Creek Ranger Districts) and Cheaha State Park. When the Talladega National Forest was established in 1936 about 30% of its area lacked forest (Duncan 2013). Forest cover, including pine plantations and successional stages, is virtually complete at present.

Stonefly Collections in the Talladega Mountain region
Collections of stoneflies (Plecoptera) previously here have been sporadic yet has led to several new species descriptions in modern times (James 1974, James 1976, Stark and Szczytko 1976, Kondratieff and Kirchner 1996, Szczytko and Kondratieff 2015. The first records of stoneflies from the Talladega Mountain region were given by Audrey James in her Ph.D research on Alabama Plecoptera (James 1972). Although she did not use the words "Talladega Mountains" in her dissertation, dot distribution maps  depicted 32 species from the region at that time. Four new regional species were included as informal manuscript names that would be formally described shortly thereafter in James (1974James ( , 1976; Table 1). Stark and Harris (1986) made several references to stonefly species from the Talladega region but only by county (i.e. Calhoun, Cleburne, Clay, and Talladega). Feminella (1996) compared aquatic insect communities along flow permanence gradients in six Talladega National Forest streams, but all stonefly taxa reported were determined only to the generic level. Since James (1974James ( , 1976, seven species have been described from the Talladega Mountain region (

Species
Leuctra crossi James, 1976 Leuctra pinhoti Grubbs and Sheldon, 2009 Zealeuctra talladega Grubbs, 2005 Family Perlidae Beloneuria jamesae Stark and Szczytko, 1976 Hansonoperla cheaha Kondratieff and Kirchner, 1996 Family Perlodidae Isoperla davisi James, 1974 Isoperla sandbergi Szczytko and Kondratieff, 2015 The origin of a biogeographic study of the stonefly fauna of the Talladega Mountains occurred after SAG traveled to the region in February 2003 looking extensively for the nemourid genus Soyedina Ricker, 1952 (none were ever found). Collections during that first trip, however, provided material leading to the description of Zealeuctra talladega Grubbs, 2005 and the first male specimen of Allocapnia menawa Grubbs and Sheldon, 2008. Shortly thereafter, ALS contacted SAG about collaborating on a focused research project and a formal sampling concept was conceived and commenced in 2005. ALS has collected mainly in upland streams throughout the region whereas SAG provided complimentary work both in upland streams and from the largest streams draining northward and southward. In total, 26 collecting trips occurred as independent endeavors by the authors between 2003 and 2012 (Table 3).

Field Methods
Most sampling in upland streams occurred in Talladega National Forest at U.S. Forest Service road crossings, adjacent to campgrounds (e.g. Turnipseed), along established hiking trails (e.g. Pinhoti National Recreation Trail), and by hiking off trail along streams. Larger streams (e.g. Hatchet Creek) were located mainly at road crossings adjacent to private land. In total, we have positive collections from 192 unique sites (Fig. 2). Some sites were located at different elevations along the same stream (e.g. Swept Creek). Sites ranged in elevation from 131-660 m (429-2165 ft). Most sites, however, were nested within a narrow range of elevations (190-390 m, n = 150) and basin areas (< 25 km , n = 176) (Fig. 3). The least common streams available for collecting were those at higher (> 500 m, n = 13) and lower (< 190 m, n = 9) elevations, and in basin areas larger than 100 km (n = 13) (Fig. 3). Nearly all data (ca. 99%) presented in this treatment were based on adult specimens. Adults, particularly males, provide the best and most objective set of characteristics for identifying species. This paper does not include the nymphal data of Acroneuria abnormis (Newman, 1838), Beloneuria jamesae Stark and Szczytko, 1976, and Eccoptura xanthenes a b c d (Newman, 1838) presented in . Adults were collected with a beating sheet to dislodge specimens from riparian vegetation, hand-picking from rocks, leaf packs, tree trunks and bridges, and use of light traps on warm evenings. The latter is especially effective for members of the family Perlidae. Specimens were preserved on site in 75-95% ethanol.

Laboratory Methods and Data Management
Location data (in decimal degrees) for each specimen record were recorded either directly on site with a portable GPS unit or georeferenced from vial label data using Acme Mapper 2016 (https://mapper.acme.com/; datum WGS-84). Drainage area for each sampling location was determined using the CONTDA function in StreamStats 4.0 (https:// streamstatsags.cr.usgs.gov/streamstats). We used drainage area as a proxy of stream size.
Regional distribution maps for all species were initially prepared using an ArcGIS public web account (http://www.arcgis.com/home) and then finished using ArcMap 10.2. Latitude and longitude coordinates in decimal degrees of all collection records for each species were overlaid on a public domain map titled "Oceans".
With the exception of type material for the four species previously described as new during this study (Table 2), most material is currently stored in 75-95% ethanol at Western Kentucky University (WKUC). All materials collected by ALS were referenced by a unique field number identifier. Data are presented in two formats. Collections are organized chronologically (Table 3) following the recommendation of Sheldon (2016) that multispecies collection data are primary, informative, and readily available. Species records, also organized chronologically, are archived in Darwin Core Archive file format supported by Pensoft's Integrated Publishing Toolkit and posted at the Global Biodiversity Information Facility (GBIF) (Grubbs and Sheldon 2017).

Species present and comparisons to prior research
Nearly 700 specimen records (= vials) and > 3200 individual specimens were obtained during this study, resulting in 57 verified species (Table 4). This species tally is conservative since we did not collect Perlinella drymo (Newman, 1839), adults of Pteronarcys Newman, 1838, and other species we expected to find during this study (see below). For several reasons outlined below, seven species listed from the region by James (1972) are not represented in Table 4.  The most speciose families found in the region as adults were Perlidae (n = 12 species), followed by Leuctridae and Perlodidae (n = 10 species each), and Capniidae (n = 9 species) (Table 4). Leuctra Stephens, 1836 (n = 9 species), Allocapnia Claassen, 1928 (n = 8 species), and Isoperla Banks, 1906 (n = 6 species) were the most speciose genera present (Table 4). Although all nine Nearctic families are present in the region, we did not collect adult specimens of Pteronarcys. The Alabama state record of P. biloba Newman, 1838 that arose from a single nymphal specimen from Cleburne County in James (1972, her Fig. 127), and carried forward in Stark and Harris (1986), Grubbs (2011), and DeWalt et al. (2017), is still considered as tentative since this specimen has not been located for study. Similarly, ALS collected Pteronarcys nymphs from eight streams ) that have been tentatively determined as P. biloba. We have also collected nymphs lacking abdominal spines that are either P. dorsata (Say, 1823) or P. pictetii (Hagen, 1873). Pteronarcys nymphs can problematic to identify to species, however, so adults are needed for confirmation. A regional distribution map for Pteronarcys spp. nymphs was included in hopes that adults of both nymphal types (i.e. abdomen with and lacking lateral spines) will be collected (Fig. 19) Four plotted records of Leuctra presented in James (1972) require clarification (Table 1). First, she plotted single records of L. alabama James, 1974 andL. alexanderi Hanson, 1941 from Calhoun and Jackson counties, respectively (her Fig. 115). These distributional points may have been inadvertently switched. Leuctra alabama was later formally described (James 1974) from a single locality in Jackson County (far northeastern Alabama) that appears to match identically to Fig. 115 in James (1972). Her singular record of L. alexanderi refers to the Calhoun County type locality of L. crossi James, 1976, a species she noted was morphologically similar to L. alexanderi in James (1972). Second, her simple line drawing (her Fig. 33) of L. biloba Claassen, 1923 is easily interpretted as L.
grandis Banks, 1906. Grubbs (2010 first reported L. grandis from the Talladega Mountains and in this study it was commonly collected across the region (Table 4). The dorsal abdominal lobes of L. grandis are consistently triangular across the broad range of this widespread Appalachian species, which is in sharp contrast to the bluntly rectangular lobes exhibited by L. biloba (Grubbs, unpublished research). Third, we did not collect L. moha Ricker, 1952 during this study. James (1972) reported this species from Alabama based only on females, including a regional locality from southern Clay County. All four regional species of Leuctra with autumnal emergence periods (L. cottaquilla James, 1974, L. ferruginea (Walker, 1852, L. tenuis (Pictet, 1841), L. triloba Claassen, 1923) were not collected during September-November south of streams draining Cheaha Mountain and Odum Point (Fig. 1). Leuctra triloba was collected from Horn Mountain but only in late January.   We collected two species of Neoperla Needham, 1905 and four species of Perlesta Banks, 1906 during this study (Table 4). At the time of James (1972), however, Neoperla was recognized only as a single, variable species (= N. clymene (Newman, 1839); Stark and Baumann 1978). The regional site record plotted in James (1972, her Fig. 128) could be one of several species, including the two reported here (Table 4). Similarly, in the early 1970s Perlesta was recognized as P. placida (Hagen, 1861), a species also of variable form at that time, and P. frisoni Banks, 1948(Stark 1989. The multiple regional records of a b Figure 19. a b Distribution dot maps for Remenus bilobatus and Pteronarcys nymphs. The red distribution dot refers to the approximate locality plotted for a single P. biloba nymph in James (1972, her Fig. 127). The black dots refer to nymphs conditionally determined as P. biloba. The blue dot refers to nymphs that could be determined only to P. dorsata or P. pictetii. P. placida plotted in James (1972, her Fig. 131) could have referred to any of the four species reported here (Table 4), including the true P. placida. In addition, we did not collect Perlinella drymo during this study. James (1972, her Fig. 131) plotted a single regional record for P. drymo from Cleburne County.
The absence of two subfamilies from the region that include eastern Nearctic species needs mention. First, the genus Megaleuctra Neave, 1934 (Leuctridae: Megaleuctrinae) does not extend southward into the Talladega Mountains. The two eastern Nearctic Megaleuctra species are restricted to cold-water systems located farther north (Baumann and Stark 2013). ALS made numerous attempts to collect Megaleuctra from high elevation seeps and springs but was unsuccessful. Second, we did not collect non-gilled nemourids (Nemouridae: Nemourinae) in the region. In addition to Soyedina, we had anticipated that species of two additional genera were present in the region. Ostrocerca truncata (Claassen, 1923) can be a locally abundant species in headwater streams, is distributed extensively along the Appalachian Mountains , and has been reported <100 km northward in DeSoto State Park (DeKalb County;Young et al. 1989). A second species, Prostoia completa (Walker, 1852), is typically found in small rivers and large streams through eastern and central North America  and was plotted in James (1972, her Fig. 126) from southern Tallapoosa County.
Increasing altitude with concomitant reduction in flow permanence and stream size, however, had no influence on uncommon or rarity patterns. Although we found 12 species at higher elevation sites (> 500 m), all were collected commonly during this study (range: 8-61 unique localities/species). Leuctra crossi was also the most common species found at higher elevation sites (n = 8 unique sites > 500 m), followed by Amphinemura nigritta (Provancher, 1876) (n = 4 unique sites), and L. alta, L. ferruginea, and A. wui (Claassen, 1936) (n = 3 unique sites each).

Succession of adult stoneflies
Helopicus subvarians was the only regional species not collected as adults. Adult data is also missing from August (Table 3); this was the only month when neither author travelled to the region. Four species of Leuctra were collected during autumn (Table 5), including two species (L. ferruginea, L. triloba) with extended emergence periods. An extended emergence period for L. ferruginea has been shown previously (Harper 1973). The life cycle of L. triloba is unknown. Species of the families Capniidae and Taeniopterygidae are "winter stoneflies" (Ross and Ricker 1971) with adult emergence at low elevations and midlatitudes typically occurring mainly from December through March. All eight regional Allocapnia species and all four Taeniopterygidae species were collected as adults between December and March (  The remaining four regional species of Leuctridae (L. alta, L. crossi, L. grandis, L. pinhoti, P. sara) and all four species of Nemouridae (Amphinemura appalachia Baumann, 1996, A. delosa, A. nigritta, A. wui) commenced emergence during the spring months (Table 5). Although both regional species of Tallaperla were often collected together, the emergence period of T. laurie extended ca. one month later compared to T. maria (Table 5).
Two regional species of Perlodidae, Clioperla clio and Isoperla sandbergi Szczytko and Kondratieff, 2015, started emergence in late winter (Table 5). The remaining five regional Isoperla species were collected as adults only during spring. The two species of Perlodinae collected as adults were found during late spring (Diploperla duplicata (Banks, 1920)) or spring-summer (Remenus bilobatus (Needham and Claassen, 1925). All six regional Chloroperlidae were also found predominantly in spring (Table 5). Alloperla chloris was the only regional chloroperlid species collected into June.
As expected, the family Perlidae was found commonly during the summer months.
Although Perlesta decipiens and P. ephelida were collected by mid-April (Table 5), most perlid species did not emerge until May. Five species, Acroneuria abnormis, A. filicis Frison, 1942, Beloneuria jamesae, Eccoptura xanthenes, Neoperla coosa Smith and Stark, 1998, and P. shawnee, were collected through late July (Table 5) and likely into August had we collected during the latter month.
Endemics and northern vs. southern regional species Seven species, including three of the family Leuctridae, may be endemic to the Talladega Mountain region (Table 4). This number should be viewed as tentative, however, because little is understood about statewide distribution patterns of stoneflies across Alabama and northeastward into Georgia. For example, Allocapnia muskogee was described as new during this study (Grubbs and Sheldon 2008) but is also known from northern Georgia (Verdone et al. 2017). Except for Zealeuctra talladega, all of the supposed endemic species may have distribution patterns extending northward through the Valley and Ridge region into adjacent northwestern Georgia. Zealeuctra talladega has been collected only in the southern Talladega Mountain region (Fig. 9). Streams draining Dugger Mountain in the northern portion of the region were particularly emphasized because this is one of the few peaks > 2000 ft (> 610 m) and to provide broad north-south spatial coverage. We have yet, however, to collect Z. talladega north of the vicinity of Cheaha Mountain.
Overall, roughly 2/3 (39 species or 68%) of species were collected both north and south of Highway I-20. Several species are likely also more represented along Choccolocco Mountain but much of this area is located in private landholdings and collections by us here were limited both in effort and number (Fig. 2). Several species were found only or mainly in northern or southern portions of the Talladega Mountain region. Characterizing any species as northern or southern Talladega regionals, however, may by spurious. For example, nine species were found only in the southern Talladega region. Yet seven of these species, Allocapnia smithi Ross and Ricker, 1971 (Fig. 6), A. virginiana Frison, 1942 (Fig. 6), Nemocapnia carolina ( Fig. 7; Stark et al. 2016), Amphinemura wui ( Fig. 10), Oemopteryx contorta (Fig. 10), Acroneuria filicis Frison, 1942 (Fig. 14), and Helopicus subvarians (Fig. 17), have distributions farther northward in eastern North America. As indicated above, Z. talladega (Fig. 9) appears restricted to the southern Talladega region but there is too little distribution data on Allocapnia menawa (Fig. 5) to be confident. On a related note, there are four species that may be restricted to the northern Talladega region: Leuctra pinhoti (Fig. 8), Amphinemura delosa (Fig. 10), Taeniopteryx maura (Fig. 11), and Alloperla usa Ricker, 1952 (Fig. 12).

Conclusions
Our combined efforts across a 10-year period resulted in 57 confirmed species from the Talladega Mountain region. Four new species (Grubbs 2005, Grubbs and Sheldon 2008, Grubbs and Sheldon 2009 were previously described during the study period. We detected clear patterns of stream size and elevation gradients with species abundance data. We expect, however, that more species are present in the region for two reasons. First, we did not collect at least one species previously reported (i.e. Perlinella drymo) by James (1972). Second, adults of two species of Pteronarcys are present but adults are needed for verification. In addition, there may be other species (i.e. Ostrocerca truncata) that we did not obtain yet may be collected at some point in the future. Seven species may be endemic, but focused collecting efforts northeastward into Georgia and examinations of museum holdings and personal collections, are needed for confirmation. This form of baseline data can be useful for managers of national forest lands, especially for species with smaller ranges (i.e. regional endemics) that are of greater risk of extinction (Pimm et al. 2014). Natural areas can protect large proportions of the regional species pool by providing intact habitat and by mitigating development within their boundaries, even in eastern US national forests which are often comprised of a mosaic of public and private landholdings.