Mapping the pine rocklands of the Turks and Caicos Islands (original) (raw)
Related papers
Conserving and restoring the Caicos pine forests: The first decade
Plant Diversity
The severe and rapid attack on the Caicos pine Pinus caribaea var. bahamensis (Pinaceae) by the nonnative invasive pine tortoise scale, Toumeyella parvicornis, has resulted in the death of most of the trees in the Turks and Caicos Islands (TCI) in just over a decade. Local and international conservation efforts have enabled the necessary multidisciplinary research, data gathering, and monitoring to develop and implement a restoration strategy for this endemic tree from the Bahaman archipelago. The native plant nursery established on North Caicos and horticultural expertise acquired throughout the years were crucial to the successful rescue of Caicos pine saplings from the wild populations and cultivation of new saplings grown from locally sourced seeds. These saplings have been used to establish six Restoration Trial Plots on Pine Cay and a seed orchard on North Caicos in TCI. Core Conservation Areas (CCAs) for the Caicos pine forests have been identified and mapped. To date, forest within the Pine Cay CCA has been supplemented by planting more than 450 pine trees, which have survived at a high (>80%) rate.
Aim Marginal populations are frequently neglected in static views of vegetation types, particularly when defining conservation reserves. The biogeographical and evolutionary importance of a marginal and endangered population of Pinus canariensis is addressed in this study to ascertain the need for conservation action. Diversity loss between adults and offspring and patterns of seed dispersal and recruitment were examined to provide evidence of recent degradation of marginal P. canariensis pinewoods. The scientific basis for the provision of sound conservation policies was investigated by elucidating the factors responsible for significant population structure.
Botanical Journal of the Linnean Society, 2014
For the first time a comprehensive population genetics study of the endemic Caribbean pine, Pinus caribaea var. bahamensis, in the Bahamas and the Turks and Caicos Islands (TCI) is undertaken. Information on inbreeding levels, genetic diversity and spatial structure in the focus taxon are important tools for its future conservation and can help guide local forest management. Plastid (pDNA) and nuclear microsatellite (nDNA) loci were used to reveal past and contemporary patterns of genetic differentiation and levels of genetic diversity and to test the hypothesis of isolation by distance of populations in the Bahamas and TCI regions. Due to its non-recombinant nature, low mutation rates and uniparental inheritance, pDNA can give an insight into an earlier state of the populations than that revealed by nDNA. Data from pDNA showed only 12 haplotypes, with one of them present in c. 81% of individuals, low unbiased genetic diversity (uh < 0.107) and lack of significant variation between regions (FCT = 0.011, P = 0.20); whereas nDNA showed higher unbiased genetic diversity (uHS > 0.487) and significant variation between regions (FCT = 0.156, P < 0.01). Isolation by distance was only significant for nDNA (r 2 = 0.56, P < 0.01). Only two of the populations had significant levels of inbreeding (FIS = 0.090, FIS = 0.113). High levels of gene flow and lack of isolation in the past were revealed by pDNA, whereas nDNA showed a more recent spatial isolation and genetic differentiation between the Bahamas and TCI populations. Conservation measures are discussed in view of the genetic diversity, inbreeding and spatial structure found in the taxon.
Theoretical and Applied Genetics, 2003
The Canary archipelago, located on the northwestern Atlantic coast of Africa, is comprised of seven islands aligned from east to west, plus seven minor islets. All the islands were formed by volcanic eruptions and their geological history is well documented providing a historical framework to study colonization events. The Canary Island pine (Pinus canariensis C. Sm.), nowadays restricted to the westernmost Canary Islands (Gran Canaria, Tenerife, La Gomera, La Palma and El Hierro), is considered an old (Lower Cretaceous) relic from an ancient Mediterranean evolutionary centre. Twenty seven chloroplast haplotypes were found in Canary Island pine but only one of them was common to all populations. The distribution of haplotypic variation in P. canariensis suggested the colonization of western Canary Islands from a single continental source located close to the Mediterranean Basin. Present-day populations of Canary Island pine retain levels of genetic diversity equivalent to those found in Mediterranean continental pine species, Pinus pinaster and Pinus halepensis. A hierarchical analysis of variance (AMOVA) showed high differentiation among populations within islands (approximately 19%) but no differentiation among islands. Simple differentiation models such as isolation by distance or stepping-stone colonization from older to younger islands were rejected based on product-moment correlations between pairwise genetic distances and both geographic distances and population-age divergences. However, the distribution of cpSSR diversity within the islands of Tenerife and Gran Canaria pointed towards the importance of the role played by regional Pliocene and Quaternary volcanic activity and long-distance gene flow in shaping the population genetic structure of the Canary Island pine. Therefore, conservation strategies at the population level are strongly recommended for this species.
Arctic, Antarctic, and Alpine Research, 2002
Variation in spatial pattern and its consequences for intraspecific aSSOCIatIOns, regeneration, and allometric relationships in a population of Pinus canariensis was studied along an altitudinal gradient at the treeline on the west-northwest slope of Pico del Teide (Mount Teide) in Tenerife, Canary Islands. We sampled II plots (20 by 20 m), situated 30 m a.s.1. apart along a 4380 m transect which ran from the treeline at (2020 m a.s.l.) to the forest interior (1720 m a.s.L), In each plot, we recorded height, diameter at breast height (DBH) and location of all tree stems (> 130 ern in height), number of seedlings and saplings, and percent cover of vegetation layers. Stand basal area and maximum tree height decreased with altitude. The spatial distribution of P. canariensis was characterized by increasing regularity with tree size irrespective of altitude. The decrease in intensity of clumping with tree-size and the uniform pattern in older stages indicated intraspecific resource competition. The tree response to increasing altitude was largely associated with restricted height growth. At the treeline, the trees similar in diameter to those of lower-altitude sites were substantially shorter. The seedling and sapling density decreased significantly with increased altitude and increased in stands with increased basal area and canopy cover. Tree density along the altitudinal transect was similar, but trees at high-altitudes were shorter with smaller crowns, thus creating less favorable conditions for seedling and sapling survival. The positive or facilitating relationship between canopy trees and seedlings and saplings suggests that environmental factors (here stressful conditions) perform a key role in seedling establishment. Our results suggest that competitive relationships among canopy trees playa key role in generating stand structure.
Introduction The recognition of endangered species takes into account geographic isolation and small size of populations, as is the case of two populations of Pinus caribaea var. hondurensis distributed in México. • Materials and methods This study evaluates the genetic variation within and among Mexican populations of P. caribaea var. hondurensis to make inferences on the historical dynamics of the populations by screening a total of 69 trees with six nuclear microsatellites. • Results The results indicate intermediate levels of genetic variation in both populations (HE = 0.465). The level of inbreeding was significant for both populations (Caobas FIS = 0.097; Pioneros FIS = 0.163), but the effective population size was higher in the Pioneros population (Ne = 868) compared to Caobas (Ne = 402). Average genetic differentiation was low (RST = 0.033) and historical migration rate was relatively high (M = 13.2). • Discussion These results, together with the analysis of bottlenecks, provide us evidence of historical events of contraction of the population size, which probably occurred between 8,100 and 35,000 years ago. We propose conservation strategies for the emergent recovery of these remaining native forest patches.
The pine rockland community in southern Florida, which supports numerous stateand federally listed flora and fauna species, is considered endangered. Without its foundation species, Pinus elliottii var. densa, habitat and species diversity are lost to tropical hardwood hammock. Here, we investigate the landscape factors that contribute to the long-term persistence of pine rocklands on the 2 islands that contain the largest remaining habitat in the Florida Keys: Big Pine Key and No Name Key. Plot-level biophysical data and island-scale remotely sensed vegetation data were collected from pine rockland savannas and examined with multi-dimensional analysis. On both islands, vegetation plots located at higher elevations contain the greatest basal area and the oldest and largest-diameter trees. In contrast, the lowest-elevation plots contain more standing dead trees and downed logs. Change-detection analysis of the normalized difference vegetation index between 2001 and 2011 supports the notion that habitat areas at lower elevations experience more vegetation change compared to those at higher elevations during the time period (p < 0.05). Trees rooted at higher elevations frequently exceeded 200 yr in age, which is uncommon in this highly disturbed sub-tropical region. Although elevation range on the 2 islands was only ca. 0 to 3 m, these results demonstrate that higher elevations can act as a refuge for the saltintolerant P. elliottii var. densa during storm surge events, which promotes long-term development of old-growth savanna structure and aids the long-term persistence of pine rocklands in the Florida Keys.