Riverscour is an eclectic assemblage of highly biodiverse riparian natural communities that share characteristics with grasslands, savannas, glades, wetlands, and floodplains. We define “riverscour” as “open riparian habitats of rocky, stable-substrate (bedrock, boulder, cobble) zones, often along high-gradient streams, where periodic high-energy flows (water, ice, debris) and edaphic factors inhibit woody vegetation and promote persistent grassland-shrubland-open woodland-outcrop communities rich in conservative heliophytes.” A key factor distinguishing riverscour from gravel and sand bars and other floodplain habitats is that these areas are underlain by more stable substrates, which resist structural reworking by floodwaters. Within Eastern Unglaciated North America, we mapped 1322 stream reaches totaling 2385.8 km containing riverscour. Given their small size, these communities support a disproportionately large number of rare, endemic, and undescribed species. For example, within a five-county area in Tennessee, riverscour makes up significantly less than 1% of the area but contributes at least 37 (25%) of the region's 150 state- and federally-listed vascular plant species. There are numerous threats to riverscour, the greatest being inundation caused by impoundment of rivers and associated downstream hydrologic alterations. Interruption of scouring processes associated with flooding and/or ice promotes succession toward larger woody species and away from open herbaceous/shrub-dominated vegetation. Other threats include invasive species, recreation pressure, and climate change. These threats, coupled with high biodiversity and historical losses, make protection and proper management of riverscour ecosystems especially important in conserving the native biodiversity of eastern North America.

Natural Protected Areas in Mexico help to conserve biodiversity. However, as a megadiverse country, it is necessary to consider other strategies that complement the conservation of species. Archaeological sites in Mexico receive the same level of federal protection as their physical spaces, with different objectives, focused on the safeguarding of culture. El Tajin, a site of archaeological monuments in Veracruz, Mexico, receives protection from the federal government because it is an important historical site. This study was conducted in the archeological zone of El Tajin to determine the diversity of epiphytic orchids and their relationship with their hosts within three different uses of the site. Orchids are probably the largest family of plants; orchids grow and develop by living on other orchids and host plants as well. Three hundred and ninety epiphytic orchids corresponding to five species were found growing on 17 host species. The orchid species with the highest abundance was Lophiaris cosymbephora. Vanilla planifolia, a species in a protected category, was identified. The quadrant with the highest tourist traffic presented the highest abundance and richness of species. Based on our findings, it is important to implement strategies that allow diversity to flourish, particularly the diversity of protected species. This can happen only if these species are cared for. This study supports the idea of considering the archaeological zone as a space for the conservation of biodiversity.

The name ramp or wild leek refers to two taxa: Allium tricoccum and A. burdickii. The latter, named narrow-leaf ramp, has historically been recognized as a variety but recently as a distinct species. Habitat differences between these species have been reported, although distribution of A. burdickii in eastern North America is unresolved. A better understanding of A. burdickii habitat will aid population discovery and conservation as A. burdickii is of conservation concern in parts of the United States. Eight populations, four for each species, were identified in southwestern Pennsylvania. The associated flora, soil fertility and moisture, and site characteristics (e.g., topography) were documented. A. tricoccum was associated with northern aspects and higher soil moisture content throughout the growing season whereas A. burdickii was found on a variety of aspects. Soil pH and nutrient content were greater at A. burdickii sites than A. tricoccum sites and suggest the former may rely more heavily on base nutrients such as calcium. The most common overstory tree associate was sugar maple (Acer saccharum) for both species but understory flora differed. Wet-mesic preferring species, including blue cohosh (Caulophyllum thalictroides) and wood nettle (Laportea canadensis), were associated with A. tricoccum, whereas dry-mesic species, including mayapple (Podophyllum peltatum) and false Solomon's seal (Maianthemum racemosum), were associated with A. burdickii. Results are consistent with observations that these species may differ in mesoscale habitat conditions due to topographic position and its influence on soil moisture and fertility.