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Restoration of abandoned agricultural lands toward umbrella species habitats

AgSAP Conference 2009, Egmond aan Zee, the Netherlands
Restoration of abandoned agricultural lands toward umbrella species
M. Arriaza, O. Nekhay and M.J. López-Baldovín
Centro IFAPA “Alameda del Obispo”. Apartado 3092. Córdoba, Spain
The present study analyses the suitability of agricultural lands with risk of abandonment to be
restored to suitable habitats for endangered species. As a case study, we focus on the olive
plantations of mountain areas of Southern Spain and the Iberian lynx. The methodology
weighs experts’ judgements about the effects of the landscape elements on this habitat via the
Analytic Hierarchy Process (AHP) and spots the most suitable areas for restoration through
the Geographical Information Systems (GIS).
The main interest of the study relies on the potentiality of the methodology to combine
complex territorial analysis with the biological requirements of endangered species to
facilitate their dispersal.
The methodology involves three phases: First, an inventory of Iberian lynx habitat
requirements is drawn up. Then, the AHP method is implemented based on the experts’
knowledge. Finally, the Geographical Information Systems technology is used to assess the
potential of the study area for Iberian lynx’s habitat restoration.
Selection of landscape elements related to Iberian lynx habitat requirements
The main causes that have brought the Iberian lynx to the border of extinction are habitat
alterations and removal, the fall in the number of rabbits (the main lynx’s prey), human
activity, such as illegal hunting and traps, (Delibes et al., 2000; Gaona et al., 1998).
Analytic Hierarchy Process multicriteria decision-making technique
There are two specific characteristics that distinguish this method (Saaty, 1980) from the
other multicriteria methods of this family: (a) the construction of the hierarchy structure of the
problem to be solved, and (b) the pair-wise comparisons made between different criteria to
weigh them with respect to the overall objective.
GIS-aided analysis
The GIS software used as a platform for the representation, management and analysis of the
spatial information was ArcGIS 9.1 and ILWIS 3.4 (Integrated Land and Water Information
System). The operations of spatial multi criteria evaluation was carried out in ILWIS 3.4.
SMCE module. The input data were: land use map (1999; 1:50,000); aerial monochrome
orthophotos (2001-2002; 1:5000) and color orthophotos (2005; 1:10,000); olive plantations
productivity maps (2004; 1:25,000); road infrastructure map (1999; 1:25,000).
This research has been financed by INIA through the research project RTA04-086.
AgSAP Conference 2009, Egmond aan Zee, the Netherlands
Results and discussion
According to the results, the most important landscape objects are the natural vegetation
structures (32%), followed by the proximity to asphalted roads (28%), the proximity to the
Natural Park (18%) and the proximity to watercourses (14%). Olive groves with vegetation
cover obtained the lowest weight (8%).
Figure 1. Evaluation of Iberian lynx habitat restoration potential
The red spot in the centre represents the urban area and it is regarded as a constraint (non-
compensatory criteria). The red lines that pass through the map represent two motorways that
have high levels of traffic. The maximum suitability value recorded in the study area was
0.92, the minimum was 0 and mean value was 0.46 (in a 0-1 scale). The green colour
represents the areas suitable to implement the restoration measures. All situated on the North
of the motorway A-IV. Since the divergences in the opinions of the experts raise a good deal
of uncertainty about the reliability of the result, we decided to perform a sensitivity analysis
of the results.
It is interesting to report some similarities between the results obtained in this study and those
provided by Van der Horst and Gimona (2005), which used multicriteria spatial analysis to
determine the most suitable territories in agricultural areas for the implementation of action
plans to promote biodiversity. Unlike the present study, these authors combine the
requirements of 15 species as map layers, weighted according to the importance of each
species. However, the results of both studies emphasise the importance of the edge zones of
major agricultural areas, the riparian zones (in our case the natural vegetation) and areas
adjacent to nature pinewoods (in our case Mediterranean forest and shrub lands) as having the
highest potential for biodiversity.
Delibes, M. et al., 2000. Action plan for the conservation of the Iberian lynx (Lynx pardinus) in
Europe. Nature Environ 111, 1-45.
Gaona P. et al., 1998. Dynamics and viability of a metapopulation of the endangered Iberian lynx
(Lynx pardinus). Ecol Monog 68, 349-370.
Saaty, T.L., 1980. The analytic hierarchy process: Planning, priority setting, resource allocation.
McGraw-Hill, NY.
Van Der Horst, D. & A. Gimona, 2005. Where new farm woodlands support biodiversity action plans:
a spatial multi-criteria analysis. Biol Conserv 123, 421-432.
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Full-text available
The use of metapopulation models in conservation biology is growing exponentially, but there is a need for empirical studies that support theoretical approaches, especially for species with large and long-lived individuals. In this paper we explore the viability and dynamics of a real metapopulation of an endangered mammal by combining field work and modeling in order to support conservation decisions and evaluate theoretical approaches. The Iberian lynx (Lynx pardinus), considered the most vulnerable felid in the world, is restricted to the Iberian Peninsula in southwestern Europe, The persistence of the species is handicapped by the high fragmentation of its populations. Fewer than 1000 individuals are distributed in nine isolated populations, each of them also fragmented but with their patches connected by dispersers, in what could be called metapopulations. One of these metapopulations, including similar to 60 individuals, inhabits the Donana National Park (DNP) and its surroundings. Demographic and behavioral data gathered over one decade for this lynx population were employed to develop a spatially realistic structured model with density-dependent fecundity and migration, including demographic and environmental stochasticity. Such a model is used to identify the demographic features that determine the dynamics of this population and to predict its risk of decline under a set of alternative assumptions. A hypothetical lynx metapopulation with values of the parameters such as those observed in Donana, but without stochastic events, could sustain itself over time. Results of this deterministic model show how females occupy all the potential breeding territories, while males are below the carrying capacity. The metapopulation has a source-sink structure, with the sources internal and the sinks external to the national park. Sinks result from reduced survival rather than reduced fecundity, as generally assumed. High mortality in sink patches is deterministic, deriving both from within-patch risks and from factors related to the landscape matrix among patches. The survival rate of adults with territories in the sources was the most sensitive parameter, leading the dynamics of the metapopulation. When we include demographic stochasticity in the model, the population becomes extinct 22% of the time within 100 yr, and this value increases to 33.8% when environmental stochasticity is also considered. Most of the metapopulation extinctions occurred because of the disappearance of males due to sex differences in demographic parameters related to behavioral aspects (e.g., dispersal rate). Different scenarios were simulated as modifications affecting either within- or between-patch dynamics. Changes in the carrying capacity of source and sink patches would have very different consequences in terms of metapopulation persistence: one breeding territory increase in the largest source reduces metapopulation extinction risk from 33.8 to 17.2% in 100 yr, while an increase of three territories in the largest sink does not modify the extinction risk. In this sense, results suggest that the best management strategy for conservation should be restoring habitat at the source patches and reducing mortality at the sinks. The results of our models emphasize the need for empirical studies to characterize metapopulations in nature and distinguish between such terms as source-sink, mainland-island, nonequilibrium, or even "refuge" metapopulations.
In many developed countries forest cover is growing and the provision of non-market benefits is increasingly important for forestry management. The benefits provided by a new woodland not only depend on the design of the woodland (local site level), but also on its location in the wider landscape. This paper develops a generic GIS-based method to map the potential biodiversity benefits of new woodlands through an integration of species-habitat modelling for a list of 15 key species derived from a "Local Biodiversity Action Plan", encompassing the Northeast of Scotland, and spatial multi-criteria analysis. For each selected species 'Preferred Future Woodland' maps are produced, indicating the extent to which populations of these species are expected to expand or contract in response to further afforestation. Species are then weighted on the basis of criteria of relative scarcity of suitable habitat and national importance of the regional population. The maps are then combined using this weighting to yield an overall potential biodiversity benefit map, which shows that the areas with the highest potential biodiversity gains are the edges of major agricultural areas (mostly deciduous), the riparian zones (deciduous) and areas adjacent to mature native pine woods (coniferous). It is demonstrated that the use of this map for more explicit spatial targeting of an existing farm afforestation scheme can help to provide much more 'biodiversity value' for taxpayers' money. (c) 2004 Elsevier Ltd. All rights reserved