Structure and growth rate of Prosopis flexuosa woodlands in two contrasting environments of the central Monte desert

Villagra, Pablo E.; Villalba, Ricardo; Boninsegna, José A.

doi:10.1016/j.jaridenv.2004.03.016

Cited by 31 publications

(31 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Vegetative reproduction and seedling banks may be another strategy of population persistence. The latter have been suggested for Prosopis flexuosa in the Monte Desert (Villagra et al 2005), an area which has a number of similarities with the Prepuna.…”

Section: Discussionmentioning

confidence: 98%

The role of nurse plants in the establishment of shrub seedlings in the semi-arid subtropical Andes

et al. 2007

View full text Add to dashboard Cite

In the nurse plant syndrome, or nurse association, seedlings (beneficiaries) are associated with adult shrubs/trees (benefactors). This phenomenon has been documented in several regions of the planet. Abiotic stress amelioration (one mechanism of facilitation) is one of the causes of this association. Most of the studies addressing the nurse syndrome have been conducted on spatial scales of a few hectares and have focused on only one or a few species. Moreover, there is an almost complete lack of studies addressing the incidence and characteristics of the nurse phenomenon in the arid Andes of South America. We undertook a first approximation to the study of facilitation in these ecosystems. The study was conducted at local and regional scales and involved the assessment of the spatial distribution of juveniles (seedlings and saplings) of 51 populations of 16 shrub and 12 cactus species in relation to shrub cover at 20 localities of the Prepuna (subtropical Andes of Bolivia and Argentina, 20-26 degrees S). In terms of spatial distribution, the juveniles of most of the populations of shrubs studied were distributed both under the shrubs and in open spaces, thereby showing an apparent indifference to microhabitat. Globose and opuntioid cacti were preferentially distributed below the canopies of shrubs and were usually more associated with the dominant shrub species, which stood out as better potential nurses. The pattern was consistent throughout the region, including the more mesic and arid localities. The fact that Prepuna woody species are capable of establishing in open spaces would confer this region a greater resilience. Our findings further suggest that community dynamics in arid and semi-arid environments are more variable than previously thought.

show abstract

Section: Discussionmentioning

confidence: 98%

The role of nurse plants in the establishment of shrub seedlings in the semi-arid subtropical Andes

et al. 2007

View full text Add to dashboard Cite

show abstract

“…This is not necessary true for all forest systems. For example, some forest systems in the Chaco region of Argentina are based on the current year's precipitation given that the phreatic level is below 70 m, inaccessible to plants (Villagra et al 2005), and one might expect, Ceteris paribus, that dD F of birds feeding in these systems to more closely track the annual values of dD P . Birds that are more closely dependent on annual plants might also be expected to reflect more of the inter-annual variation in dD P .…”

Section: Discussionmentioning

confidence: 99%

Fundamental limits to the accuracy of deuterium isotopes for identifying the spatial origin of migratory animals

2008

View full text Add to dashboard Cite

Deuterium isotope analyses have revolutionized the study of migratory connectivity because global gradients of deuterium in precipitation (deltaD(P)) are expressed on a continental scale. Several authors have constructed continental scale base maps of deltaD(P) to provide a spatial reference for studying the movement patterns of migratory species and, although they are very useful, these maps present a static, 40-year average view of the landscape that ignores much underlying inter-annual variation. To more fully understand the consequences of this underlying variation, we analyzed the GNIP deuterium data, the source for all current deltaD(P) maps, to estimate the minimum separation in deltaD(P) (and latitude) necessary to conclude with a given level of confidence that distinct deltaD(P) values represent different geographic sites. Extending analyses of deltaD(P) successfully to deuterium in tissues of living organisms, e.g., feathers in migratory birds (deltaD(F)), is dependent on the existence of geographic separation of deltaD(P), where every geographic location has a distribution of values associated with temporal variability in deltaD(P). Analyses were conducted for three distinct geographic regions: North America, eastern North America (east of longitude 100 degrees W), and Argentina. At the 80% confidence level, the minimum separation values were 12, 7, and 14 degrees of latitude (equivalent to 53, 31, and 32 per thousand) for North America, eastern North America, and Argentina, respectively. Hence, in eastern North America, for example, one may not be able to accurately assign individual samples to sites separated by less than about 7 degrees of latitude as the distributions of deltaD(P) were not distinct at latitudes <7 degrees apart. Moreover, two samples that differ by less than 31 per thousand cannot be confidently said to originate from different latitudes. These estimates of minimum separation for deltaD(P) do not include other known sources of variation in feather deuterium (deltaD(F)) and hence are a first order approximation that may be useful, in the absence of more specific information for the system of interest, for planning and interpreting the results of new stable isotope studies.

show abstract

“…In areas of the Monte desert with different total annual precipitation amounts and different accessibility to the water-table by plants, population structure, and growth rate of P. flexuosa show differences that could be attributed to the type of the water sources: e.g., the faster rate of radial growth may respond to the presence of a nearsurface phreatic layer (Villagra et al 2005). In our study site, the accessibility of the roots to deep water sources may allow extra supplies of water throughout the year, complementing the contributions of the regional rainfall necessary for the radial growth of P. flexuosa.…”

Section: Discussionmentioning

confidence: 99%

Annual variation and influence of climate on the ring width and wood hydrosystem of Prosopis flexuosa DC trees using image analysis

Giantomasi

Roig

Villagra

et al. 2008

Trees

View full text Add to dashboard Cite

We developed chronologies based on the width of tree rings, total area of vessels, and the number of vessels per tree ring of the Prosopis flexuosa wood samples from the xerophytic woodlands of central Argentina. We evaluated the influence of climate on these tree-ring characteristics considering the period from 1940 to 2004 (65 years). The width of the rings, the number of vessels, and the total area of vessels were positively influenced by regional precipitation corresponding to the seasonalized November to December period, which reflects the importance of the water availability in the initial stage of the formation of the wood. The width of the rings and the total area of vessels were negatively influenced by temperature during the same period, while the number of vessels was not significantly correlated with temperature. The high temperatures in spring increase evapotranspiration, which reduces water availability to plants and results in an inverse growth response. This study was the first to develop chronologies based on anatomical characters of wood from the arid and semiarid regions of South America and with significant applications in ecological and climatic studies.

show abstract

Structure and growth rate of Prosopis flexuosa woodlands in two contrasting environments of the central Monte desert

Cited by 31 publications

References 19 publications

The role of nurse plants in the establishment of shrub seedlings in the semi-arid subtropical Andes

The role of nurse plants in the establishment of shrub seedlings in the semi-arid subtropical Andes

Fundamental limits to the accuracy of deuterium isotopes for identifying the spatial origin of migratory animals

Annual variation and influence of climate on the ring width and wood hydrosystem of Prosopis flexuosa DC trees using image analysis

Contact Info

Product

Resources

About