Nest sites as a key resource for population persistence: A case study modelling nest occupancy under forestry practices

Abstract

Natural nest sites are important breeding resource in terms of population dynamics, especially in forest systems where nest trees limit populations or timber harvesting destroys nests. Nest structures usually have a long life and can be reused by breeding pairs across multiple breeding seasons, so studying their dynamics is of relevance for biodiversity conservation. In this study, we develop a dynamic model to evaluate nest site availability and its influence on the breeding settlement of a forest raptor community composed of booted eagle (Hieraaetus pennatus), common buzzard (Buteo buteo) and northern goshawk (Accipiter gentilis) in a Mediterranean forest ecosystem in southeast Spain. This model approach is also applied to analyse the influence of forestry practices on the dynamics of occupied nests for a simulated period (2010–2050). The simulated scenarios include unmanaged forest and timber harvesting practices of clearcuttings every ten years considering two factors: the age class of trees for clearcutting (40, 50, 60 and 70 years old) and the type of forest management (with or without nest protection). Our simulated results show that the number of breeding pairs is constant during the period without timber harvest, whereas breeding pairs gradually decrease in the scenario of clearcutting trees aged from 70 to 50-years without nest protection, and populations become extinct with the clearcutting of 40-year old trees. Considering the practice of clearcutting and nest protection, nest occupancy can reach the maximum number of occupied nests for the scenarios of cutting 70 and 60-year old trees, and maintain populations without extinction for the scenarios of cutting 40-year old trees. We conclude that nest sites (whether occupied or not) are key resources for increasing the occupancy of the forest raptor community and that nest protection measures buffer the effects of clearcuttings, thus preventing population extinction.

Declining American Goshawk (Accipiter atricapillus) Nest Site Habitat Suitability in a Timber Production Landscape: Effects of Abiotic, Biotic, and Forest Management Factors

“…Previous studies found harvest activities at the nest-stand scale resulted in fewer nests used by goshawks (Byholm et al 2020), and goshawk nest sites or territories with less harvest nearby or with relatively large trees were more likely to be occupied (Rodriguez et al 2016). Harvest limits available nest sites and use by forest-dwelling raptors (Jiménez-Franco et al 2018). Therefore, retaining natural stand structure and limiting extensive commercial treatments is important, but pre-commercial thinning could be used to improve structure in nest areas of forest-dwelling raptors (Lõhmus 2005).…”

Models d’idoneïtat d’hàbitat de l’astor: una eina per a la conservació de les pinedes de pi blanc

“…A més, el 100% dels nius localitzats al final d'aquesta darrera campanya (n=46) es troben a les zones definides amb el 60% d'idoneïtat. El model, per tant, sembla una eina útil per obtenir una cartografia predictiva de la presència d'astor, primer objectiu del treball, i delimitar aquelles zones de bosc millor conservades a escala arbre, tal i com definien a priori els treballs de Sergio et al (2005), García-Salgado (2018) i Jiménez-Franco et al (2018. També es va poder observar a la representació del model que, a aquesta escala, les zones potencialment favorables es trobaven dins de rodals més o menys extensos de pi blanc.…”

“…Els models a escala de territori i, especialment, el de rodal, aporten localitzacions d'hàbitat òptim continu dins els forests que poden abastar fins a desenes d'hectàrees. Aquesta extensió correspon aproximadament amb les àrees immediatament al voltant dels nius utilitzats, però també conté, si hi són presents, altres nius coneguts d'altres anys que s'han rebutjat, essent la preservació del conjunt de tots els nius de gran importància per a la conservació dels rapinyaires forestals (Jiménez-Franco et al 2018). Els indrets amb major desenvolupament dels arbres són els primers rodals que es tallen, ja siguin per treballs silvícoles de prevenció d'incendis o aprofitaments forestals.…”

Differential utilization of surface and arboreal water bodies by birds and mammals in a seasonally dry Neotropical forest in southern Mexico

“…These effects can escalate to affect the structure and dynamics of animal communities. Examples of limiting resources affecting bird and mammal communities include shared prey (Gilg et al., 2003 ), nectar‐producing flowers (Guevara et al., 2023 ), and cavities for nesting birds (Jiménez‐Franco et al., 2018 ).…”