Assessing the ability of novel ecosystems to support animal wildlife through analysis of diurnal raptor territoriality

Abstract

Novel ecosystems have emerged through human intervention and are rapidly expanding around the world. Whether they can support animal wildlife has generated considerable controversy. Here we developed a new approach to evaluate the ability of a novel forest ecosystem, dominated by the exotic tree species Eucalyptus globulus, to support animal wildlife in the medium and long term. To evaluate this ability, we took advantage of the fact that species territory size decreases with increasing habitat quality, and we used territoriality of a raptor guild composed of Northern Goshawk (Accipiter gentilis), Eurasian Sparrowhawk (A. nisus) and Common Buzzard (Buteo buteo) as indicator. We compared the territoriality of these species in the novel ecosystem with that in other ecosystems found in the literature. Average distances between con-specifics in the novel ecosystem were similar, or even shorter, than those in other ecosystems. Average distances between Goshawk con-specifics were among the shortest described in the literature. All three species nested preferably in mixed stands abundant in large exotic trees, with high structural complexity and abundance of native species within the stand. Key factors supporting this diverse and dense raptor community were the special forest management system implemented in the study area and the agricultural matrix located close to forest plantations that complements the supply of prey. Our results suggest that forest management that promotes a complex and suitable forest structure can increase the ability of novel forest ecosystems to support wildlife biodiversity, particularly a diverse nesting community of forest-dwelling raptors and their preys. The results further suggest the suitability of territoriality for assessing this potential of novel ecosystems.

Anything for a quiet life: shelter from mobbers drives reproductive success in a top‐level avian predator

“…Over the last decades, we have observed how goshawks increasingly prey on racing pigeons, which is a lucrative activity within the study area (Rebollo et al 2017a). In recent years, we have detected illegal trap killing of goshawks in the study area, which coincided with a decrease in the number of goshawk breeding pairs (Martínez-Hesterkamp et al 2018). The pigeon-raptor conflict is in fact a worldwide human-raptor conflict that requires effective yet socially acceptable solutions (Parrott et al 2008).…”

“…Forest patches were systematically surveyed on foot for goshawk nests in order to locate active nests every year for the period 2008–2011 (see details in García‐Salgado et al 2018 and Martínez‐Hesterkamp et al 2018). These surveys are part of a long‐term ecological research program focused on the diurnal raptor community since 2004 and continuing to the present (2022).…”

“…Land cover types were digitised using a geographic information system (Arc‐GIS 10, ESRI 2010). To verify the classification of land cover types, we surveyed all UTM (Universal Transverse Mercator) 1 × 1 km 2 grids in April–May 2011, covering 200 grid cells and spending an average of 36 min per grid cell checking and validating the land cover types and their spatial limits (Martínez‐Hesterkamp et al 2018). At a detailed spatial scale, farmland areas contain multiple small forest patches or are close to woodland‐farmland ecotones.…”

Services provided by birds (high-mobile link species) in farmland and forest mosaics: forest regeneration and plague regulation

“…Nuestros resultados mostraron que la comunidad de rapaces puede ser densa y diversa en estos mosaicos agroforestales (Rebollo et al 2011). La densidad de parejas reproductoras fue, para algunas especies ornitófagas como el azor (Accipiter gentilis), una de las más elevadas del mundo (Martínez-Hesterkamp et al 2018a). Hasta el momento sólo hemos publicado datos de la dieta del azor, la rapaz con mayor interés para el control de la avifauna potencialmente plaga en los viñedos estudiados.…”

“…En la selección del lugar de nidificación de las rapaces estudiadas influyeron, por orden de importancia, la competencia intra-específica, la complejidad estructural del bosque y las interacciones inter-específicas en el gremio de rapaces. Las parejas se distribuyeron en el espacio de manera regular y las distancias mínimas medias entre parejas activas oscilaron entre 2080-2433 m en el azor, 1310-1774 m en el gavilán (Accipiter nisus) y 1071-1657 m en el busardo ratonero (Buteo buteo) dependiendo del año (Martínez-Hesterkamp et al 2018a). Esta acusada territorialidad intra-específica posiblemente limita la densidad local de parejas reproductoras.…”