Tillandsia candida

In Central and South America, epiphytes have experienced dramatic population decreases mainly because of habitat loss and extraction activities, which have driven many species close to extinction (Mondragon et al. 2006). Caatinga originally covered ca 70% of the vegetative cover of northeast Brazil. At least 50% of the Caatinga has been either completely converted from its native vegetation or modified in a major way by human activities (i.e., the second/third most degraded ecosystem in Brazil) (Da Silva 2001, Leal et al. 2005). Specific activities include: unsustainable timber extraction for fuel, clearance for pastures, overgrazing, slash and burn agriculture, "Sertanjos" (conversion of remnant vegetation to new and short lived crops), extensive and uncontrolled fires and, more recently, cotton and sugar cane cultivation.

Fragmentation of forests is a major cause of bromeliad extinction. It causes local and regional extirpation of emergent trees (key habitats for epiphytic bromeliads) and vertebrate seed dispersers, a reduction in pollinator abundance and leads to habitat desiccation and invasion of ruderal plants. Fragments are therefore more prone to fire, which appears to be detrimental to many bromeliad species (Benzing 2000, Ariani et al. 2004, Filho and Leme 2007). Forest fragmentation also facilitates the extraction of ornamental species (Benzing 2000, Filho and leme 2006, Filho and Tabarelli 2006), including many Tillandsia spp. However, microclimatic conditions in fragmented landscapes, which are generally drier and more exposed force a shift from shade loving, mesic to sun loving and drought tolerant bromeliads (Wolf 2005, Filho and Leme 2006, Cascante-Marin et al. 2009). Type V Tillandsia are usually drought tolerant and often heliophile. Tillandsoid epiphytes, especially atmospheric (type V) Tillandsia, are frequently reported to occur in higher abundance compared to other bromeliad species and types of epiphytes in disturbed sites, where higher light and drought stress are common (Cascante-Marin et al. 2008, Reyes-Garcia et al. 2008).

Many bromeliads have become very important horticultural plants because of their unique appearance (Barfuss et al. 2005). Bromeliads may also be of ornamental or ceremonial value to indigenous people. As a consequence, there is a local and rapidly expanding international market for bromeliads, which are collected in large numbers from natural populations without control of the extraction rate (Read 1989, Wolf and Konings 2001). Over the last 20 years, bromeliads have become more popular in Brazil as home and garden ornamentals and this has promoted increasing collection pressures on wild populations (Versieux and Wendt 2007). It is not known whether T. candida is collected for these purposes but commercial exploitation of wild populations may develop unchecked as new groups of plants become fashionable (Read 1989, Cascante-Marin 2009). Tillandsia species are relatively difficult to propagate and take several years to flower from seeds. Propagation by offsets, which form after flowering, is only in a limited number. These increase the incentive to collect wild specimen for direct sale. There is considerable evidence that many plants for sale are collected from the wild in Central and South America.

In the northeastern Atlantic Forest, some ornamental bromeliads have been intensively collected and almost eliminated from forest fragments close to human settlements (Filho and Tabarelli 2006). In Mexico, the volume of illicitly traded epiphytes in local markets exceeds legal exports and comprise many species (Toledo-Aceves and Wolf 2008). Bromeliads with narrow geographic distribution can be considered extremely vulnerable to commercial exploitation. Grey leaved Tillandsia, like T. candida, are the most at risk.

This species was collected outside any protected areas. It does not benefit from any legal protection in Brazil. Less than 1% of the Caatinga is protected in parks or reserves (Da Silva 2001). Although biodiversity conservation has consistently been one of the lowest investment priorities in the region, new conservation initiatives on small scale are now being implemented and new protected areas developed (Leal et al. 2005).

Current occurrence of the taxon needs first to be confirmed. Surveys and census should be conducted in the type locality and potentially suitable sites of occurrence to determine the current size and range of the population and whether local extinction has occurred. The population should be closely monitored and its dynamics studied. The habitat conditions, availability of propagules, dispersal characteristics and requirement for seedlings establishment as well as breeding system and genetic structure of the population should be studied (Cascante-Marin et al. 2006).

The taxon is grown in various botanical institutions. Seeds have not yet been collected for germplasm conservation. There is no national protection in law covering this species.