Christopher E. Moorman

EFFECTS OF GROUP-SELECTION OPENING SIZE ON BREEDING BIRD HABITAT USE IN A BOTTOMLAND FOREST

Research on the effects of creating group-selection openings of various sizes on breeding birds habitat use in a bottomland hardwood forest of the Upper Coastal Plain of South Carolina. Creation of 0.5-ha group selection openings in southern bottomland forests should provide breeding habitat for some field-edge species in gaps and habitat for forest-interior species and canopy-dwelling forest-edge species between gaps provided that enough mature forest is made available.

Proceedings: the role of fire for nongame wildlife management and community restoration: traditional uses and new directions

Contains 16 papers and 4 abstracts on the use of fire for nongame wildlife management and rare plant community management in restoration in the United States with an emphasis on forested systems.

Hooded Warbler Nesting Success Adjacent to Group-selection and Clearcut Edges in a Southeastern Bottomland Forest

Abstract During the 1996, 1997, and 1998 breeding seasons, we located and monitored Hooded Warbler (Wilsonia citrina) nests in a bottomland forest and examined the effects of edge proximity, edge type, and nest-site vegetation on nesting success. Successful Hooded Warbler nests were more concealed from below and were located in nest patches with a greater abundance of >0.5-m-tall switchcane (Arundinaria gigantea) stems than unsuccessful nests. Daily nest survival rates, clutch size, and number of fledglings per successful nest did not differ between nests near edges of selection-harvest openings within the bottomland and nests near edges of clearcuts adjacent to the bottomland. Daily survival rate, clutch size, and number of fledglings per successful nest did not differ among nests 0–50 m, 51–100 m, and >100 m from the nearest edge, and probability of nest survival was not related to proximity to either edge type. However, probability of parasitism by Brown-headed Cowbirds (Molothrus ater) was higher near clearcut edges, and parasitism reduced clutch size and numbers of fledglings per successful nest. The combined effects of edge, especially edge created by the relatively small (≤0.5 ha) group-selection openings, on Hooded Warbler nesting success were minimal. However, our study was conducted in a primarily forested landscape, so cowbird abundance or negative edge effects may have been low relative to agricultural landscapes in the South. Éxito de Anidación de Wilsonia citrina en Sitios Adyacentes a Bordes de Claros Formados por Extracción de Árboles Seleccionados y por Tala Rasa en Bosques Ribereños del Sureste Resumen. Durante las épocas reproductivas de 1996, 1997 y 1998, ubicamos y monitoreamos nidos de Wilsonia citrina en un bosque de ribereño y evaluamos los efectos de la proximidad al borde, el tipo de borde y la vegetación del sitio de anidación sobre el éxito reproductivo. Los nidos exitosos estuvieron más escondidos desde abajo y se ubicaron en parches de bosque con una mayor abundancia de tallos de Arundinaria gigantea de más de 0.5 m de alto que los nidos no exitosos. Las tasas de supervivencia diaria de los nidos, el tamaño de la nidada y el número de polluelos emplumados por nido exitoso no difirieron entre nidos ubicados cerca de bordes de aperturas de cosecha selectiva dentro del valle ribereño y nidos cerca de bordes de sitios completamente talados adyacentes al valle. La tasa de supervivencia diaria, el tamaño de la nidada y el número de polluelos emplumados por nido exitoso no difirió entre nidos ubicados a 0–50 m, 51–100 m y >100 m del borde más cercano, y la probabilidad de supervivencia de los nidos no estuvo relacionada con la proximidad a ningún tipo de borde. Sin embargo, la probabilidad de parasitismo por Molothrus ater fue mayor cerca de bordes de tala rasa, y el parasitismo redujo el tamaño de la nidada y el número de polluelos emplumados por nido exitoso. Los efectos combinados de borde sobre el éxito de anidación de W. citrina fueron mínimos, especialmente aquellos de los bordes creados por los claros relativamente pequeños (≤0.5 ha) formados tras extraer grupos de árboles seleccionados. Sin embargo, nuestro estudio fue realizado en un paisaje principalmente forestal, de modo que la abundancia de M. ater o los efectos de borde negativos pueden haber sido menores en relación a paisajes agrícolas del sur.

Response of Reptiles and Amphibians to Repeated Fuel Reduction Treatments

Abstract Recent use of prescribed fire and fire surrogates to reduce fuel hazards has spurred interest in their effects on wildlife. Studies of fire in the southern Appalachian Mountains (USA) have documented few effects on reptiles and amphibians. However, these studies were conducted after only one fire and for only a short time (1–3 yr) after the fire. From mid-May to mid-August 2006 and 2007, we used drift fences with pitfall and funnel traps to capture reptiles and amphibians in a control and 3 replicated fuel-reduction treatments: 1) twice-burned (2003 and 2006), 2) mechanical understory cut (2002), and 3) mechanical understory cut (2002) followed by 2 burns (2003 and 2006). We captured fewer salamanders in mechanical + twice-burned treatment areas than in twice-burned and control treatment areas, but we captured more lizards in mechanical + twice-burned treatment areas than in other treatment areas. Higher lizard captures in mechanical + twice-burned treatment areas likely was related to increased ground temperatures and greater thermoregulatory opportunities. Higher and more variable ground temperatures and faster drying of remaining litter and duff may have led to fewer salamander captures in mechanical + twice-burned treatment areas. Our longer term results, after 2 prescribed burns, differ from shorter term results. After one prescribed burn at the same site, eastern fence lizard (Sceloporus undulatus) captures were greater in mechanical + burn treatment areas but salamander captures did not differ among treatment areas. Our results indicate that multiple (≥2) fuel-reduction treatments that decrease canopy cover may benefit lizards but negatively affect salamanders.

Southern two-lined salamanders in urbanizing watersheds

Forested riparian buffers are an increasingly common method of mitigating the negative effects of impervious surface cover on water quality and wildlife habitat. We sampled larval southern two-lined salamanders (Eurycea cirrigera) in 43 streams, representing the range of impervious surface cover and forested riparian buffer width across Wake County, NC, USA. Larval abundance decreased with increasing impervious surface cover in the upstream catchment, but was not affected by buffer width. This is likely a result of an incomplete buffer system and culverts or other breaches along streams. Larval abundance increased with detritus cover in the stream to a threshold and then decreased as detritus continued to increase. As percent pebble substrate in the stream increased, especially in perennial streams, larval salamander abundance also increased. We suspect salamanders were unable to migrate with the water column during dry periods in intermittent streams with sedimented interstices below the surface, resulting in low abundances. A combination of increased peak flows and sedimentation, reduced base flow, and chemical changes likely reduces the abundance of salamanders in urban and suburban streams. We suggest creation of catchment-wide, unbreached buffers to maintain the integrity of stream habitats in urbanizing watersheds.

The Importance of Habitat Shape and Landscape Context to Northern Bobwhite Populations

Abstract Northern bobwhite (Colinus virginianus) populations have declined nationally for at least the past 4 decades. Field borders have been promoted as an important component of conservation plans to reverse this decline. Field border characteristics, such as shape and the landscapes in which the borders are established, have the potential to influence their effectiveness for recovering northern bobwhite populations. We established narrow linear (approx. 3-m-wide) and nonlinear field borders on farms in agriculture-dominated and forest-dominated landscapes in the Coastal Plain of North Carolina, USA, after collecting pretreatment data on summer bobwhite abundance. After establishment of field borders, summer bobwhite abundance nearly doubled on farms in agriculture-dominated landscapes and increased approximately 57% on farms with nonlinear field borders. Summer bobwhite abundance did not increase on farms with linear field borders in forest-dominated landscapes. Nonlinear and narrow linear field borders can be used to increase bobwhite numbers on farms in landscapes dominated by agriculture. Less flexibility exists in forest-dominated landscapes, where we found only nonlinear field borders resulted in an increase.

Do biological and bedsite characteristics influence survival of neonatal white-tailed deer?

Coyotes recently expanded into the eastern U.S. and potentially have caused localized white-tailed deer population declines. Research has focused on quantifying coyote predation on neonates, but little research has addressed the potential influence of bedsite characteristics on survival. In 2011 and 2012, we radiocollared 65 neonates, monitored them intensively for 16 weeks, and assigned mortality causes. We used Program MARK to estimate survival to 16 weeks and included biological covariates (i.e., sex, sibling status [whether or not it had a sibling], birth weight, and Julian date of birth). Survival to 16 weeks was 0.141 (95% CI = 0.075-0.249) and the top model included only sibling status, which indicated survival was lower for neonates that had a sibling. Predation was the leading cause of mortality (35 of 55; 64%) and coyotes were responsible for the majority of depredations (30 of 35; 86%). Additionally, we relocated neonates for the first 10 days of life and measured distance to firebreak, visual obstruction, and plant diversity at bedsites. Survival of predation to 10 days (0.726; 95% CI = 0.586-0.833) was weakly associated with plant diversity at bedsites but not related to visual obstruction. Our results indicate that neonate survival was low and coyote predation was an important source of mortality, which corroborates several recent studies from the region. Additionally, we detected only weak support for bedsite cover as a covariate to neonate survival, which indicates that mitigating effects of coyote predation on neonates may be more complicated than simply managing for increased hiding cover.

White-Tailed Deer Vigilance: The Influence of Social and Environmental Factors

Vigilance behavior may directly affect fitness of prey animals, and understanding factors influencing vigilance may provide important insight into predator-prey interactions. We used 40,540 pictures taken withcamera traps in August 2011 and 2012to evaluate factors influencing individual vigilance behavior of white-tailed deer (Odocoileus virginianus) while foraging at baited sites. We used binary logistic regression to determine if individual vigilance was affected by age, sex, and group size. Additionally, we evaluated whether the time of the day,moon phase,and presence of other non-predatorwildlife species impacted individual vigilance. Juveniles were 11% less vigilant at baited sites than adults. Females were 46% more vigilant when fawns were present. Males and females spent more time feeding as group size increased, but with each addition of 1 individual to a group, males increased feeding time by nearly double that of females. Individual vigilance fluctuated with time of day andwith moon phase but generally was least during diurnal and moonlit nocturnal hours, indicating deer have the ability to adjust vigilance behavior to changing predation risk associated with varyinglight intensity.White-tailed deer increased individual vigilance when other non-predator wildlife were present. Our data indicate that differential effects of environmental and social constraints on vigilance behavior between sexes may encourage sexual segregation in white-tailed deer.

INFLUENCE OF PATCH SIZE AND SHAPE ON OCCUPANCY BY SHRUBLAND BIRDS

Abstract. Populations of many shrubland bird species are declining in the eastern United States. Efforts to restore shrubland and early-successional forest may help to ameliorate these declines. However, uncertainty remains about how the size and shape of habitat patches and the surrounding habitat matrix affect patch occupancy by shrubland passerines. Our objectives were to determine if shrubland birds avoid small or irregularly shaped habitat patches and to identify minimum area requirements for area-sensitive species. Additionally, we sought to determine if the proportion of mature forest cover in the landscape influences patch occupancy. We surveyed 35 individual habitat patches in 2007 and 43 in 2008 for the presence of eight shrubland birds. Then, we modeled the probability of five of these species occupying an individual patch relative to patch area, patch shape, and percent forest cover within 1 km of the patch. We documented evidence of area sensitivity for the Yellow-breasted Chat (Icteria virens) and Prairie Warbler (Setophaga discolor) and estimated their minimum area requirements at 2.3 and 1.1 ha, respectively. The Blue Grosbeak (Passerina caerulea) also was area-sensitive in irregularly shaped patches. Predicted patch-occupancy probability was >0.9 in patches ≥5.5 ha for all area-sensitive species. Patch shape alone and proportion of forest cover were not important predictors of occupancy for these shrubland birds. Restored shrubland and early-successional forest in agricultural landscapes can provide habitat for many shrubland birds, but patches should be >5 ha to maximize shrubland bird diversity.

SEASONAL BIRD USE OF CANOPY GAPS IN A BOTTOMLAND FOREST

Abstract Bird use of small canopy gaps within mature forests has not been well studied, particularly across multiple seasons. We investigated seasonal differences in bird use of gap and forest habitat within a bottomland hardwood forest in the Upper Coastal Plain of South Carolina. Gaps were 0.13- to 0.5-ha, 7- to 8-year-old group-selection timber harvest openings. Our study occurred during four bird-use periods (spring migration, breeding, postbreeding, and fall migration) in 2001 and 2002. We used plot counts and mist netting to estimate bird abundance in canopy gaps and surrounding mature forest habitats. Using both survey methods, we observed more birds, including forest-interior species, forest-edge species, field-edge species, and several individual species in canopy gap and gap-edge habitats than in surrounding mature forest during all periods. Interactions between period and habitat type often were significant in models, suggesting a seasonal shift in habitat use. Bird activity generally shifted between the interior of canopy gaps and the immediate gap edge, but many species increased their use of forested habitat during the breeding period. This suggests that many species of birds selectively choose gap and gap-edge habitat over surrounding mature forest during the non-breeding period. Creation of small canopy gaps within a mature forest may increase local bird species richness. The reasons for increased bird activity in gaps remain unclear.