New England Wild Flower Society

About: New England Wild Flower Society is a archive organization based out in Framingham, Massachusetts, United States. It is known for research contribution in the topics: Population & Species richness. The organization has 8 authors who have published 19 publications receiving 1421 citations.

The Loss of Species: Mangrove Extinction Risk and Geographic Areas of Global Concern

Abstract: Mangrove species are uniquely adapted to tropical and subtropical coasts, and although relatively low in number of species, mangrove forests provide at least US $1.6 billion each year in ecosystem services and support coastal livelihoods worldwide. Globally, mangrove areas are declining rapidly as they are cleared for coastal development and aquaculture and logged for timber and fuel production. Little is known about the effects of mangrove area loss on individual mangrove species and local or regional populations. To address this gap, species-specific information on global distribution, population status, life history traits, and major threats were compiled for each of the 70 known species of mangroves. Each species' probability of extinction was assessed under the Categories and Criteria of the IUCN Red List of Threatened Species. Eleven of the 70 mangrove species (16%) are at elevated threat of extinction. Particular areas of geographical concern include the Atlantic and Pacific coasts of Central America, where as many as 40% of mangroves species present are threatened with extinction. Across the globe, mangrove species found primarily in the high intertidal and upstream estuarine zones, which often have specific freshwater requirements and patchy distributions, are the most threatened because they are often the first cleared for development of aquaculture and agriculture. The loss of mangrove species will have devastating economic and environmental consequences for coastal communities, especially in those areas with low mangrove diversity and high mangrove area or species loss. Several species at high risk of extinction may disappear well before the next decade if existing protective measures are not enforced.

Comparative ecophysiology of four wetland plant species along a continuum of invasiveness

Abstract: We compared the ecophysiological performance of four dominant, perennial plant species of tidal marshes of northeastern North America (Phragmites australis, Typha angustifolia, Spartina alterniflora, and Leersia oryzoides), asking whether species that fall along a continuum of invasiveness vary consistently in terms of primary productivity, growth, biomass allocation, phenology, maximal photosynthetic rate, leaf turnover, tissue nutrient and chlorophyll content, and water use. During 1999, we examined plants growing at two brackish marshes and two freshwater tidal marshes in southern Connecticut, USA. Phragmites and Typha consistently exceeded the other two species in both marsh types in terms of ramet biomass, standing crop, length of the growing season, standing leaf area, leaf longevity, and total chlorophyll. Typha, Phrag- mites, and Spartina showed similar maximal photosynthetic rates across marsh types, significantly greater than the P max observed in Leersia. Foliar nitrogen was significantly greater in Phragmites than in all other species, suggesting that this species accrues nutrients more efficiently. Phragmites and Typha populations did not differ in a number of characters between freshwater and brackish marshes, indicating low sensitivity to exposure to moderate salinity levels. A principle components analysis placed Phragmites and Typha close to each other and more distant from Spartina and Leersia along axes describing components of competitive ability and photosynthetic performance. Thus, moderately and highly invasive species are distinct from less invasive species in terms of ecophysiology in both wetland types. As Phragmites australis and Typha an- gustifolia displace other plant species in marshes, they will likely influence the carbon- and nitrogen-cycling functions of wetlands, subject to the species' varying tolerances for salinity.

Is purple loosestrife (lythrum salicaria) an invasive threat to freshwater wetlands? conflicting evidence from several ecological metrics

Abstract: Conflicting interpretations of the negative impacts of invasive species can result if inconsistent measures are used among studies or sites in defining the dominance of these species relative to the communities they invade. Such conflicts surround the case of Lythrum salicaria (purple loosestrife), a widespread exotic wetland perennial. We describe here a 1999 study in which we quantified stand characteristics of L. salicaria and associated vegetation in arrays of 30 1-m2 plots in each of five wet meadows in Connecticut, USA. We explored linear and non-linear relationships of above-ground plant biomass, stem density, and indices of species richness, diversity, and composition to gradients of L. salicaria dominance, including stem density, percent cover, and biomass. Species richness, other diversity metrics, and stem density of other species were not significantly correlated with the density or percent cover of L. salicaria stems. The relative importance values (number of quadrats in which they were found) of co-occurring species in low-density L. salicaria quadrats were significantly correlated with their relative importance in high-density L. salicaria quadrats, indicating that only modest shifts in abundance occurred as L. salicaria increased in density. No individual species were consistently associated with or repelled by the presence of L. salicaria across sites. In contrast to density and diversity features, however, the total biomass of species other than L. salicaria was significantly, negatively correlated with the total biomass of L. salicaria at each site surveyed. Lythrum salicaria in pure, dense stands maintained a greater above-ground standing biomass on invaded sites than uninvaded vegetation of similar physiognomy. This study demonstrates that hypotheses about L. salicaria effects can vary depending upon the ecological metric that is examined. Where one-time, correlative studies are the most feasible option, data taken on a range of metrics—especially biomass—should be taken to inform us about mechanisms by which L. salicaria invades and predominates in wetlands.

Hormones and shifting ecology throughout plant development

Abstract: Hormones modulate complex suites of ecologically relevant behaviors through interactive cascades of signal transduction; evolutionary changes in the function of a single hormone can result in multiple changes in plant traits. Sites of hormone action and tissue sensitivity change throughout plant ontogeny, as embryos, seedlings, and reproductively mature plants cope with shifting suites of environmental variables and resource availability. Phenotypic plasticity and correlations and trade-offs between life history traits (such as resource use efficiency and allocation to growth and differentiation of meristems) also change as plants age; hormonal changes are central to these shifts. I synthesize evidence from the molecular and physiology literature and present novel data on mangrove propagules, seedlings, saplings, and trees. Together, these data demonstrate that several ecologically important traits are hormonally mediated (both in the short term and over evolutionary time) in the diversification of plant lineages. I focus on two hormones with contrasting action: (1) abscisic acid (ABA), which regulates internal plant osmotic stability, membrane integrity, seed dormancy, and stomatal conductance; and (2) cytokinins (zeatin and allied adenine derivatives), which promote cell division, stimulate growth, delay leaf senescence, enhance the capacity of tissues to act as N sinks, and help to transduce signals of light and nutrient availability. ABA and cytokinin levels are correlated with patterns of osmotic tolerance, photosynthesis, growth, and leaf longevity, and their concentrations in specific tissues change throughout plant development. Ecologists and evolutionary biologists are in a strong position now to creatively comprehend, predict, and potentially engineer plant strategies and adaptive trade-offs over plant lifetimes in light of emerging knowledge of hormones.

Next-Generation Field Guides

Abstract: To conserve species, we must first identify them. Field researchers, land managers, educators, and citizen scientists need up-to-date and accessible tools to identify organisms, organize data, and share observations. Emerging technologies complement traditional, book-form field guides by providing users with a wealth of multimedia data. We review technical innovations of next-generation field guides, including Web-based and stand-alone applications, interactive multiple-access keys, visual-recognition software adapted to identify organisms, species checklists that can be customized to particular sites, online communities in which people share species observations, and the use of crowdsourced data to refine machine-based identification algorithms. Next-generation field guides are user friendly; permit quality control and the revision of data; are scalable to accommodate burgeoning data; protect content and privacy while allowing broad public access; and are adaptable to ever-changing platforms and browsers...