Residual Patches and their Contribution to Forest‐Bird Diversity on Northern Minnesota Aspen Clearcuts

Abstract

Managers of upland forest generally operate with the assumption that leaving residual timber in clearcuts is beneficial for wildlife. Our primary objective in this study was to evaluate the contribution of residual patches to forest birds by (1) characterizing differences in components of bird diversity between clearcuts with and without residual patches, (2) characterizing differences in components of bird diversity between residual patches and clearcut edges, and (3) describing any clearcut-wide effects of residual patches for any bird species or group. Breeding birds were surveyed in 40 aspen clearcuts (20 clearcuts with and 20 clearcuts without residual patches) 3-9 years old from May to July 1993 in northern Minnesota. Sixteen additional survey points were established, eight each in clearcut edge and in clearcuts with residual patches but with the survey point outside the residual patch. Two diversity indices, four avian nesting guilds, and 12 bird species showed significant differences between treatments when analyzed with multiple regression analysis and analysis of variance. Five of the seven species significantly associated with residual patches are of high regional management concern: Veery ( Catharus fuscescens ), Ovenbird ( Seiurus aurocapillus ), Rose-breasted Grosbeak ( Phucticus ludovicianus ), Canada Warbler ( Wilsonia canadensis ), and Black-throated Green Warbler ( Dendroica virens ). Results from this study suggest that residual patches contribute to forest-bird diversity in northern Minnesota aspen clearcuts, and may enhance bird populations on regional and landscape scales.Las Reservas Forestales y su Contribución a la Diversidad de la Avifauna del Bosque en Matarrasas de Álamos del Norte de Minnesota Resumen: Los administradores de bosques de altura generalmente postulan la idea de que el dejar pequeñas reservas forestales en zona de tala es beneficioso para la vida silvestre. El objetivo principal de este estudio fue el de evaluar la contribución de las reservas forestales a la diversidad de la avifauna del bosque. Esto se llevó a cabo mediante (1) Caracterización de los componentes de la diversidad de la avifauna con y sin áreas de reservas forestales; (2) Caracterización de las diferencias de los componentes de la avifauna entre áreas de reserva y de tala; (3) Descubrir los efectos que tiene la tala de las áreas de reserva en las especies de aves o grupos de aves. Aves en reproducción fueron estudiadas en el norte de Minnesota en 40 parcelas de tala de álamos 3 a 9 años de edad (20 en zonas con reservas y 20 en zonas sin reservas) durante los meses de mayo a julio de 1993. Deiciséis parcelas de estudios fueron establecidos, 8 en zonas de tala sin reservas y 8 en zonas de tala con reservas, pero con puntos de observación fuera de la zona de reserva. Diferencias significativas entre tratamientos se encontraron mediante Análisis de Regresión Múltiples y Análisis de Varianza (ANOVA) utilizando dos índices de diversidad, cuatro grupos de la avifauna anidando y 12 especies de aves. Se encontró ...

Silviculture for old-growth attributes

“…However, a detailed review of the large body of literature on effects of retention is beyond the scope of this paper. The following studies provide examples of the benefits of retention on birds and understorey (Merrill et al, 1998;Beese and Bryant, 1999), canopy lichens (Coxson and Stevenson, 2005), aerial insects (Deans et al, 2004), ground-layer bryophytes (Dovčiak et al, 2006), small terrestrial mammals (Gitzen et al, 2007) and saproxylic beetles (Jonsell and Weslien, 2003). Since the retention of structural attributes has not been practised for very long, short-term responses (assumption 1) are documented better than the long-term responses (assumption 2).…”

Songbird response to experimental retention harvesting in red pine (Pinus resinosa) forests

“…Many studies have been conducted on responses of wildlife to the retention of mature trees in harvest operations, including a review by Thompson et al (2003) and a meta-analysis by Schieck and Song (2006). Several themes emerge, including that retention of 15-80% of the overstory can maintain habitat for many species found in mature, unharvested stands (Hansen et al, 1995;Schmiegelow et al, 1997;Merrill et al, 1998;Leupin et al, 2004;Schieck and Song, 2006). However, in all of these studies, the bird communities observed in harvested stands always differed from those in unharvested stands.…”

Benefits of aggregate green tree retention to boreal forest birds

“…Previous studies have suggested that bird communities in retention forest are not the same as communities in mature or old-growth forest (Merrill et al, 1998;Preston and Harestad, 2007;Atwell et al, 2008). However, studies have also demonstrated that forest patches can provide habitat for at least some forest species (Hansen et al, 1995;Schmiegelow et al, 1997;Seip and Parker, 1997;Merrill et al, 1998;Schieck and Hobson, 2000) although in all of these studies only occupancy or abundance were examined.…”

“…However, studies have also demonstrated that forest patches can provide habitat for at least some forest species (Hansen et al, 1995;Schmiegelow et al, 1997;Seip and Parker, 1997;Merrill et al, 1998;Schieck and Hobson, 2000) although in all of these studies only occupancy or abundance were examined. In this study, we compared boreal bird abundance and breeding in residual forest patches with plots of dispersed retention and intact forest during the breeding season.…”