Fruits produced as a result of reproductive biology studies at four sites in Big Bend National Park were sent to Desert Botanical Garden where seeds were and-cleaned and counted to determine number of seeds per fruit for each treatment at each site. Numbers of seeds per fruit vary considerably with numbers ranging from 200 to over 700. The seed viabilities and germination percentages are now being tested at Desert Botanical Garden.

(Desert Botanical Garden 2000) Big Bend National Park has actively worked to conserve the species since 1982, when the species was included in the Natural Resources Management Plan. Permanent monitoring plots were established and plants that were salvaged from road work were sent to the Chihuahuan Desert Research Institute and Desert Botanical Garden.

During 1999, Dr. Bonnie Amos, from San Angelo State University, and Chris Vassilou conducted reproductive biology studies on Echinocereus chisoensis at four sites in Big Bend National Park. They applied four treatments at each site: open-pollination, self-pollination (exclosing flowers before and after selfing), cross-pollination with pollen collected from nearby plants, and exclosed with no manipulation. Fruit set was high on open-pollinated plants, demonstrating that pollinator activity is adequate. Cross-pollinated flowers yielded similar results as open-pollinated flowers. The exclosed and selfed plants produced very few fruits, leading to the conclusion that Echinocereus chisoensis is probably self-incompatible. Fruits produced as a result of these studies were sent to Desert Botanical Garden where seeds were and-cleaned and counted to determine number of seeds per fruit for each treatment at each site. Numbers of seeds per fruit vary considerably with numbers ranging from 200 to over 700. The seed viabilities and germination percentages are now being tested at Desert Botanical Garden. (Desert Botanical Garden 2000) Big Bend National Park has actively worked to conserve the species since 1982, when the species was included in the Natural Resources Management Plan. Permanent monitoring plots were established and plants that were salvaged from road work were sent to the Chihuahuan Desert Research Institute and Desert Botanical Garden.

Fruits produced as a result of reproductive biology studies at four sites in Big Bend National Park were sent to Desert Botanical Garden where seeds were and-cleaned and counted to determine number of seeds per fruit for each treatment at each site. Numbers of seeds per fruit vary considerably with numbers ranging from 200 to over 700. The seed viabilities and germination percentages are now being tested at Desert Botanical Garden. (Desert Botanical Garden 2000) Big Bend National Park has actively worked to conserve the species since 1982, when the species was included in the Natural Resources Management Plan.

There are about 10 known occurrences known, with probably fewer than 1000 individuals in total. This variety's range is limited to a very small area on the southeastern side of Big Bend National Park in extreme southwestern Texas. It is threatened with extinction due to collection. Although not mentioned in the 1994 Kartesz checklist or the 1999 Synthesis, Kartesz (discussion with Larry Morse, 1Jul99) does not question the existence or distinctiveness of the variety; its omission was merely the result of a policy decision to omit from the checklist typical varieties (or subspecies) for species for which no other varieties (or subspecies) occur within his geographical territory.

The major threat to these cacti is collection, environmental stress and lack of reproductive fitness. Populations accessible by roadways are thought to be in decline (USFWS 1982).

The population occurs within a single area in Big Bend National Park, with 11 occurrences (numbers of individuals are low in each population, as there are only ca. 1,000 individuals in 7 populations) (USFWS 1982a, USFWS 1993).

Research on E. chisoensis has been active since the late eighties, with the species studied by Texas Parks and Wildlife (McMahan et al. 1984), and the staff at Big Bend National Park (Evans 1986, Alex and Norland 1987, Norland 1987). During 1999, Dr. Bonnie Amos, from San Angelo State University, and Chris Vassilou conducted reproductive biology studies on Echinocereus chisoensis at four sites in Big Bend National Park. They applied four treatments at each site: open-pollination, self-pollination (exclosing flowers before and after selfing), cross-pollination with pollen collected from nearby plants, and exclosed with no manipulation. Fruit set was high on open-pollinated plants, demonstrating that pollinator activity is adequate. Cross-pollinated flowers yielded similar results as open-pollinated flowers. The exclosed and selfed plants produced very few fruits, leading to the conclusion that Echinocereus chisoensis is probably self-incompatible. Fruits produced as a result of these studies were sent to Desert Botanical Garden where seeds were and-cleaned and counted to determine number of seeds per fruit for each treatment at each site. Numbers of seeds per fruit vary considerably with numbers ranging from 200 to over 700. The seed viabilities and germination percentages are now being tested at Desert Botanical Garden. (Desert Botanical Garden 2000) Big Bend National Park has actively worked to conserve the species since 1982, when the species was included in the Natural Resources Management Plan. Permanent monitoring plots were established and plants that were salvaged from road work were sent to the Chihuahuan Desert Research Institute and Desert Botanical Garden.

Management at Big Bend National Park has been conducted with an awareness of the status of E. chisoensis. The Park has been working with Texas State Parks and Wildlife, San Angelo State University, U.S. Fish and Wildlife Service, and Desert Botanical Garden to investigate the reproductive biology of E. chisoensis.

Populations require continued monitoring, biotic and abiotic features of the community and how they interact with this species need to be studied (USFWS 1993).

Desert Botanical Garden has an ongoing agreement with the US Fish and Wildlife Service to establish a conservation seedbank of thirteen rare plants that grow in west Texas, including Echinocereus chisoensis. Under this agreement, some of the seeds sent to Desert Botanical Garden will be seedbanked both at the Garden and at National Seed Storage Lab. The apparently low reproductivity of this species may be linked directly to seed ecology. In addition to traditional studies, we would also like to explore a hydration-rehydration technique of seed germination developed by Joseph Dubrovsky (1996). Dubrovsky allowed seeds of three species of cacti, Stenocereus thurberi, Ferocactus peninsulae and Pachycereus pecten-aboriginum, to imbibe, then dehydrate, then re-imbibe. The treated seeds germinated faster than untreated seeds, a strategy for survival allowing seedlings to accumulate a greater biomass during optimal conditions for germination and initial growth.