Geology topics

B. Cabezudo

Publications and source records attributed to B. Cabezudo.

3 recordsLinked to original sources

USGS2013

Developmental instability of gynodioecious Teucrium lusitanicum

Developmental instability was assessed in two geographical races of Teucrium lusitanicum using morphometric measures of vegetative and reproductive structures. T. lusitanicum is a gynodioecious species. Male sterile (female) individuals showed greater developmental instability at all sites. Plants located inland had higher developmental instability of vegetative characters and lower developmental instability of reproductive characters than coastal plants. These results support the contentions that (1) developmental instability is affected more by the disruption of co-adapted gene complexes than by lower heterozygosity, and (2) different habitat characteristics result in the differential response of vegetative and reproductive structures.

Evolutionary Ecology↗

USGS2003

Quantitative characterization of the regressive ecological succession by fractal analysis of plant spatial patterns

We studied the effect of grazing on the degree of regression of successional vegetation dynamic in a semi-arid Mediterranean matorral. We quantified the spatial distribution patterns of the vegetation by fractal analyses, using the fractal information dimension and spatial autocorrelation measured by detrended fluctuation analyses (DFA). It is the first time that fractal analysis of plant spatial patterns has been used to characterize the regressive ecological succession. Plant spatial patterns were compared over a long-term grazing gradient (low, medium and heavy grazing pressure) and on ungrazed sites for two different plant communities: A middle dense matorral of Chamaerops and Periploca at Sabinar-Romeral and a middle dense matorral of Chamaerops, Rhamnus and Ulex at Requena-Montano. The two communities differed also in the microclimatic characteristics (sea oriented at the Sabinar-Romeral site and inland oriented at the Requena-Montano site). The information fractal dimension increased as we moved from a middle dense matorral to discontinuous and scattered matorral and, finally to the late regressive succession, at Stipa steppe stage. At this stage a drastic change in the fractal dimension revealed a change in the vegetation structure, accurately indicating end successional vegetation stages. Long-term correlation analysis (DFA) revealed that an increase in grazing pressure leads to unpredictability (randomness) in species distributions, a reduction in diversity, and an increase in cover of the regressive successional species, e.g. Stipa tenacissima L. These comparisons provide a quantitative characterization of the successional dynamic of plant spatial patterns in response to grazing perturbation gradient. ?? 2002 Elsevier Science B.V. All rights reserved.

Cabo de Gata Natural Park↗

USGS2001

Translational and fluctuating asymmetry as tools to detect stress in stress-adapted and nonadapted plants

Plants having experienced previous exposure to a stress are expected to be more resistant to further stress than those not having been exposed. While the assessment of stress in plants is a difficult task, particularly for stress-adapted plants, developmental instability has proven a useful tool for assessing stress in organisms. We examined the effect of water availability on developmental instability (translational asymmetry and fluctuating asymmetry) and growth of Anthyllis cytisoides L. under a precipitation gradient. We compared A. cytisoides in very xeric (Almeri??a, 256 mm of average rainfall) and subhumid (Ma??laga, 613 mm of average rainfall) areas, from north- and south-facing slopes, after both a period of extreme drought (1995) and a humid period (1997). Translational symmetry varied between north- and south-exposed plants but differently for the Almeri??a and Ma??laga populations. We observed that developmental stability was enhanced in south-exposed plants in the population from the more xeric habitat (Almeri??a) after both dry and humid periods. In contrast, A. cytisoides living in a subhumid habitat did not alter their developmental stability in response to exposure after a humid period but exhibited a decline in stability in south-exposed slopes after a dry period. That is interpreted as a consequence of the adaptation of A. cytisoides to aridity. Growth patterns were also investigated. By reducing growth, plants can mitigate stress through a reduction of water and nutrient demands, allowing the maintenance of a steady supply of nutrients for developmental stability. This strategy was followed by plants acclimated to drought. But in mild weather, such as that of Montes de Ma??laga, a high growth rate cannot be supported when water is scarce. We also observed that floral fluctuating asymmetry was greatest on north-facing slopes at both the Almeri??a and Ma??laga sites. That is, southern exposure enhanced floral homeostasis during development. Additionally, comparisons between translational and fluctuating asymmetry showed that translational asymmetry is more sensitive to environmental change than fluctuating asymmetry.

International Journal of Plant Sciences↗