We are currently working on two projects:
- Human impacts on great bustard population dynamics
- Plan of preventive, corrective and compensatory measures to redress Great Bustards and other steppe birds of the Important Bird Area ‘Talamanca-Jarama’ and the LIC ‘Cuenca de los ríos Jarama y Henares’ for the construction of the highways M-50 and R-2
Financed by: Dirección General de Investigación, Ministry of Science and Innovation (Project CGL2008-02567)
1 January 2009 – 31 December 2013
Principal researcher: Juan C. Alonso
Habitat fragmentation reduces the flow of individuals between populations, constituting a major risk of biodiversity loss. The great bustard is a globally endangered species that has recently suffered dramatic declines due to agriculture intensification, and human-induced habitat fragmentation. The Iberian Peninsula represents, with more than half the world total, the species’ last stronghold, but conservation measures are urgently needed to maintain genetic diversity, counteract isolation, and prevent the species’ extinction. This project aims to assess the impact of changing land-use patterns, and other important human-induced sources of mortality, on great bustards in Iberia, and to propose ways to reconcile agricultural and rural development with species survival. This will be achieved through integration of our large data series obtained through radiotracking during the last two decades on individual behaviour and population dynamics (mating system, dispersal capability, migratory behaviour, annual recruitment, mortality, longevity), habitat availability (carrying capacity, satellite imagery) and genetic structure of the population (mitochondrial and nuclear DNA analyses) in spatially-explicit simulation models. The models will (a) help testing relevant hypotheses of metapopulation theory, (b) provide an analytical framework for assessing how patterns of land use affect the long-term survival of bustards, and (c) indicate ways to minimize human impacts on the conservation of the species and its habitat.
The project aims to assess human impacts on the viability of great bustards in Iberia, the last stronghold of this globally endangered species. We will test the hypothesis that changing land-use patterns, habitat fragmentation, and other human impacts are affecting the species’ survival by reducing the contact between isolated groups, decreasing genetic diversity, and altering fundamental demographic parameters (annual recruitment, sex ratio, mortality).
- To assess the current status, population trends and habitat availability of great bustards in selected Iberian subpopulations by defining the sizes and shapes of suitable habitat patches, and assessing for each patch its carrying capacity and degree of isolation from all others.
- To update and revalidate the current distribution and habitat availability of the species in Iberia during the breeding and non-breeding season.
- To assess the current impact of human-induced negative factors on the population dynamics of selected subpopulations by (i) obtaining detailed estimates of relevant demographic parameters through radiotracking marked birds (lifetime reproductive success, mortality, age of first breeding, longevity, natal and breeding dispersal rates and distances) or long-term surveying of leks (sex ratio, age structure, productivity), and (ii) studying spatial and recent temporal variations of these parameters among breeding groups subject to various degrees of fragmentation and human influence (hunting pressure, land-use changes, and human infrastructures).
- To assess the extent and distribution of the species’ composite genetic diversity in the Iberian Peninsula, weigh up the significance of individual populations to the overall genetic diversity, and relate patterns of genetic variability with spatial distribution in habitat quality (landscape genetics).
- To elucidate the historical landscape-level processes (climatic, physiographic and ecological changes) or human factors (past hunting pressure and agricultural transformations) that have shaped the current distribution pattern of the species.
- To identify non-viable populations and propose rational measures for the conservation of the species in the context of sustainable development.
The research is considered relevant because:
It represents the obvious culmination of a research line carried out throughout the last 2 decades by our team, thanks to which the great bustard is today one of the best studied endangered species of Europe; the effort invested in previous projects justifies the current proposal, in order to obtain reliable data and approriate samples of certain demographic parameters that need several years in long-lived and complicated species like the great bustard.
Our previous results (see CV and www.proyectoavutarda.org) and records on behaviour, habitat use, dispersal and migration (>800 individuals marked and radiotracked up to now, >120 of them still alive), genetics (>800 samples) constitute the necessary baseline data for rigorous modelling of habitat availability, space use and population viability.
The continued study of a species throughout many years is of unique value to understand its life history and population dynamics, and the effects of human intervention in a system where responses are slow must also be analyzed from long-term data series.
Most great bustard populations outside Iberia, and many breeding groups within Iberia, have gone extinct during the last decades, or are severely threatened with extinction, but the causes of these decrceases are still poorly known.
The great bustard is a globally threatened species, and the Iberian population is the only one with guaranteed survival probabilities in the long term; thus, the study proposed can only be done in Spain, although its conclusions will be applicable in other populations of the species worldwide.