Bird Diversity and Composition in Even-Aged Loblolly Pine Stands Relative to Emergence of 13-year Periodical Cicadas and Vegetation Structure
In southern Arkansas, l&year periodical cicadas (Magicicada spp.) were expected to emerge in late April and early May of 1998. Presence of a superabundant food source, such as periodical cicadas, may attract greater numbers of b i r d s a n d m o r e s p e c i e s o f b i r d s t h a n i s u s u a l l y p r e s e n t i n a p a r t i c u l a r a r e a . T h r e e e v e n a g e d l o b l o l l y p i n e (Pinus faeda L . ) stands were surveyed for birds by using a fixed-width transect before, during, and after emergence of the periodical c i c a d a s . E m e r g i n g c i c a d a n y m p h s w e r e t r a p p e d a n d c o u n t e d t o o b t a i n a n e s t i m a t e o f c i c a d a d e n s i t y . T h e d e n s i t y o f cicadas in these pine stands was considerably lower than densities reported for other forest stands in the Eastern U.S. Bird d i v e r s i t y w a s v a r i a b l e b e t w e e n m o n t h s a n d s t a n d s b u t d i d n o t a p p e a r t o b e s t r o n g l y i n f l u e n c e d b y t h e p r e s e n c e o f p e r i o d i c a l c i c a d a s . B i r d c o m p o s i t i o n i n t h e s e m a n a g e d l o b l o l l y p i n e s t a n d s w a s s i m i l a r t o t h a t i n u n m a n a g e d , e v e n a g e d p i n e a n d p i n e / h a r d w o o d s t a n d s o f s i m i l a r a g e s . INTRODUCTION Emergence of periodical cicadas (Homoptera: Cicadidae: Magicicada) is a highly predictable occurrence. The l3-year race of periodical cicadas that occurs in Arkansas is a group of three species including Magicicada tredecim (Walsh and Riley), M. tfedecassirti (Alexander and Moore), and M. tredecula (Alexander and Moore). Adult cicadas synchronously emerge from the ground every 13 years, ascend the nearest tree, and cast their nymphal skin. Adult males aggregate in the forest canopy and form chorusing centers to attract females for mating (Williams and Smith 1991). Adults complete their reproductive cycle and die within 4 to 6 weeks. Adult populations of periodical cicadas can be very dense. Populations in previous emergences have been estimated at tens of thousands to hundreds of thousands of individuals per acre (Dybas and Davis 1962, Rodenhouse and others 1997, White and others 1962). This type of ephemeral, high density occurrence of insects can provide a superabundance of food that may attract greater numbers and more species of insectivorous birds than is usually present in a particular location. In this study, we investigated the influence of 13-year periodical cicadas on bird diversity in even-aged stands of loblolly pine (Pinus taeda L.) in southern Arkansas where periodical cicadas were observed during a previous emergence (personal observation, M.D. Cain, 1985). The study also provided an opportunity to examine bird composition relative to vegetation structure of loblolly pine stands that were managed to maximize pine development. Others have examined bird composition relative to vegetation structure in unmanaged, even-aged pine and pine/hardwood stands (Childers and others 1986, Conner and others 1979, Conner and others 1983, Dickson and Segelquist 1979, Kellner 1996), but this information is lacking for managed stands. Recent concern over declining populations of neotropical migratory songbirds and an increasing interest in managing forests at the ecosystem level warrants an examination of bird communities inhabiting forests managed for timber production (Finch and Stangel 1993). METHODS Study Sites Three plots were surveyed for birds and cicadas on the Crcssett Experimental Forest, Ashley County, Arkansas. Merchantable-sized trees (a3.5 in. d.b.h.) on all plots were primarily loblolly pine, but a few shortleaf pine (Pinus echinafa Mill.) and assorted hardwood species were present. Plot 5 is a 1 O-acre, 25year-old stand measuring 1,320 ft long and 330 ft wide. This stand was precommercially and commercially thinned and periodically prescribe burned in winter (Cain 1996). Burning was initiated in the ninth year to control understory vegetation. The most recent bum was conducted in February 1998. Plot 5 also had patches of unmanaged pine and openings that supported grasses and forbs. Plots 37N and 37s are both 15-year-old loblolly pine stands. Plot 37N is 1,000 ft long and 165 ft wide (3.8 acres), and plot 37s is 660 ft long and 330 ft wide (5.0 acres). As part of one ongoing study, plots 37N and 37s have been similarly managed (Cain 1997). Both plots were precommercially and commercially thinned and competing vegetation was controlled with herbicides, manual removal, or both during the first 5 years of pine development. These two plots also had patches of unmanaged pine. All plot boundaries were well-defined by mowed fire lanes. Bird Survey Birds were surveyed using a fixed-width transect (Mikol 1980). A transect was established through the center of each plot. Bird surveys were conducted along each transect for 2 days each in early-April, mid-May, and mid-June of 1998. Each 2-day survey was completed within a 4-day period. All birds detected by sight or sound within the plot boundary were recorded and plotted on a map as the observer slowly traversed the transect. In addition, all birds detected within 80 ft outside the plot boundary were recorded and mapped for two reasons. First, birds were not confined to our artificially-defined boundaries. Second, birds in the periphery were observed using the study plots. ’ P a p e r p r e s e n t e d a t t h e T e n t h B i e n n i a l S o u t h e r n S i l v i c u l t u r a l R e s e a r c h C o n f e r e n c e , S h r e v e p o r t , L A , F e b r u a r y 1 6 1 8 , 1 9 9 9 . ’ Biological Science Technician and Research Forester, USDA Forest Service, Southern Research Station, P.O. Box 3516, Monticello, AR 71656,
Effects of Loblolly Pine Plantations on Songbird Dynamics in the Virginia Piedmont
Avifauna was sampled in 8 developmental stages of loblolly pine (Pinus taeda) plantations and in 2nd growth pine-hardwood forests during the summer, winter, and spring seasons of 1979-80 in the central Piedmont of Virginia. During summer, the number of birds (N) peaked in the 2and 5-year-old plantations and dropped significantly (P < 0.05) in older plantations. Average N of species/stand (S), total N of species in all stands of a given developmental stage (T), and species diversity (H') followed a similar trend. N, S, and T were significantly (P < 0.05) lower in the 2nd growth forests than in younger plantations. N, S, T, and H' were lower in winter than in other seasons sampled. N, S, and H' values were higher in the 2-5-year-old pine plantations than in the older, 7-24-year-old plantations. Values for 2nd growth forests were comparable to those in the 7-24-year-old plantations. In the spring breeding season, N, S, T, and H' were similar to those found during the later summer period. Species equitability (J') remained relatively high in all stands surveyed. J. WILDL. MANAGE. 50(3):406-413 Loblolly pine is one of the major tree species used by the forest industry in Virginia. Although not native to the study area in the central Piedmont, it was introduced in the early 1930's and has proved more profitable than the native pines (Williston and Huckenpahler 1958, Smally and Pierce 1972). Abandoned farmlands were used as plantation sites until the mid-1950's when this type of land increased in value. Forest industries then were compelled to use lower value, 2nd growth hardwood stands for plantation sites by clearcutting and planting loblolly pine. This conversion practice has created major changes in the composition and structure of the vegetation found in the central Piedmont (Felix et al. 1983) and may have effects on nongame wildlife species. The objective of this study was to determine the effects of establishment and development of loblolly pine plantations on the relative density, abundance, and diversity of breeding and winter resident songbirds. We would like to acknowledge P. T. Bromley and J. D. Fraser for their reviews of earlier drafts of this paper.
Effects of silviculture on neotropical migratory birds in central and southeastern oak pine forests
Avian communities that are associated with forest habitat attributes are affected by silvicultural and other stand influences. Some species have specific habitat requirements, whereas others occupy a broad range of vegetative conditions. In general, bird species richness and density are positively related to stand foliage volume and diversity. Bird density and diversity are usually high in young brushy stands, decrease in dense pole stands as canopies close and shade out understories, and are highest in older stands with diverse foliage strata. Tree harvesting generally favors early successional species such as the Indigo Bunting, Prairie Warbler, and Yellow-breasted Chat, but some late successional forest species, such as the Black-and-white Warbler, persist with partial cutting. A few forest interior species, such as the Ovenbird, are less abundant in landscapes with cutting and forest fragmentation. Some species may have elevated nest parasitism and nest predation along forest edges. Recommendations for NTMB include: Maintain some large, old-growth stands; manage foresf habitat for NTMB; employ special measures for endangered or sensitive species; implement long-term monitoring; and develop more complete information through research regarding NTMB, population viability, and their forest habitat. Central hardwood, loblolly-shortleaf pine, longleaf-slash-pine, and bottomland hardwood forests dominate the central and southeastern United States. These forests are managed by both even-aged and uneven-aged silvicultural systems. We review the impacts of silvicultural practices on neotropical migratory birds (NTMB), in forests of this region. We approach this topic by (1) identifying general relationships between birds and forest habitats and landscapes in the region, (2) assessing effects of forest management on the NTMB in each ecosystem, and (3) conclude with some management strategies that extend across forest types.