Abstract The factors that determine the size of benefits to landowners who participate in the use‐value assessment program under the California Land Conservation Act are identified, and the level of benefits available to landowners is calculated for several cropping patterns in Sacramento County. Possibilities for decisionmakers to increase participation by altering benefits is examined through a sensitivity analysis on the factors that determine benefit levels. It is concluded that little opportunity exists for decisionmakers to influence enrollment significantly except through measures that influence land values or development expectations of landowners.
The Sacramento splittail (Pogonichthys macrolepidotus) is a cyprinid fish endemic to the Central Valley of California with a range that centers on the San Francisco Estuary. It is a state Species of Special Concern and was only recently (2003) delisted as a threatened species by the U. S. Fish and Wildlife Service. Splittail live 7-9 years, tolerate a wide range of environmental conditions, and have high fecundity. Typically, adults migrate upstream in January and February and spawn on seasonally inundated floodplains in March and April. In May the juveniles migrate back downstream to shallow, brackish water rearing grounds, where they feed on detritus and invertebrates for 1-2 years before migrating back upstream to spawn. Seven long-term sampling programs in the estuary indicate that the splittail population is maintained by strong year classes resulting from successful spawning in wet years, although some spawning occurs in all years. Modeling shows them to be resilient, but managing floodplains to promote frequent successful spawning is needed to keep them abundant. Additionally, it is important to provide safe migration corridors between spawning and rearing grounds as well as abundant high-quality brackish water rearing habitat. Key research needs are (1) to examine how the timing, magnitude, and duration of high flows contribute to the generation of strong year classes, (2) to describe differences in young of year survival on the floodplain and in river margins from hatching to down-river migration, (3) explore the possible trophic effects of new invaders such as the overbite clam and Siberian prawn, and (4) determine the response of splittail populations to climate change and sea level rise.
Secondary succession in former sheep pastures in the northern California coastal prairie favors cover dominance by perennials, especially grasses. Studies of secondary succession at Sea Ranch, Sonoma County, show that the relative cover is dominated increasingly by Anthoxanthum odoratum, an perennial grass. Native species are not successful at increasing their cover during succession and are unlikely to regain cover dominance in the coastal prairie. Historically, large parts of the California coastal prairie were used for grazing by domestic animals. One of the main effects of grazing in this grassland is a change in species composition, accomplished by selection against grazing-intolerant species. Grazing has been implicated as a major factor in the change of vegetation in the Central Valley (Burcham 1957), and is likely to have been important in the coastal zone as well, although such changes have never been documented. Secondary succession may be defined as the predictable sequence of species replacements occurring after a disturbance such as grazing defoliation. It differs from primary succession only in that the latter is assumed to start from a substrate that has not been occupied previously by any vegetation. Secondary succession is the ecological process governing change in species composition once grazing pressure is reduced or eliminated, and thus successional studies may reveal whether or not the natural recovery process can ameliorate the effects of grazing (see Mcintosh 1980). The classic expectation of the effects of secondary succession are based on early work by Clements (1916), who argued that succession would favor species, which are well adapted to each other and their physical environment. Invaders and weedy species, however, would be crowded out eventually and recovery to the original climax vegetation would be complete. More recently, Heady and others (1977) have predicted that introduced plants will continue Madrono, Vol. 33, No. 3, pp. 189-206, 1986 This content downloaded from 207.46.13.128 on Wed, 07 Sep 2016 06:03:40 UTC All use subject to http://about.jstor.org/terms 190 MADRONO [Vol. 33 to be abundant on many hectares of coastal prairie, but succession will apparently move rapidly toward dominance of perennial grasses if land management practices are suitable. This is a modified Clementsian view, which recognizes that invading species may not be so easily displaced. Heady refers specifically to the replacement of annuals by perennial grasses in the coastal prairie. Although Mediterranean annuals are commonly treated as the dominant vegetation of interior valleys, they have been as abundant in the coastal prairie flora, at least in range systems. Studies in secondary succession would appear to be useful in California prairies for several basic and applied reasons. There are a number of succession models proposed (e.g., Connell and Slatyer 1 977, Shugart 1 984) that could be tested using California vegetation. On the other hand, range and reserve managers could use such information in management and restoration activities. Despite the obvious need, secondary succession in the coastal prairie is not well known at present. Those few studies that exist suggest that species may dominate the vegetation as succession proceeds. Huffaker and Kennett (1959) showed that perennial grasses, especially one species ( Danthonia californica) replaced an perennial ( Hypericum perforatum) known as Klamath weed, following successful biological control by the Klamath weed beetle ( Chry solina hyperici) in the coastal prairie of Humboldt County. Elliott and Wehausen (1974) analyzed cover in three plots with different grazing pressure in Point Reyes National Seashore. Their data predict that the coastal shrub Baccharis pilularis and the perennial bunchgrass Deschampsia holciformis would increase during succession. Lathrop and Gogan (1985) surveyed the Tule Elk Range at Tomales Point, immediately to the north of the area studied by Elliott and Wehausen. They argued that shrubs would dominate secondary succession in wind-protected areas, but that perennial grasses would also increase (particularly the perennial Stipa pulchra Hitchcock). The invasion of prairie by northern coastal scrub is indicated by their data, and is more strongly suggested by the work of McBride and Heady (1968) and McBride (1974). It is not clear, however, that the coastal prairie is a serai stage whose climax is ultimately shrub or forest dominated. Despite the evidence suggesting the successional superiority of species over species, it is far from conclusive. A number of counter examples, demonstrating the tenacity of invading species, also exists; perhaps the best example is that of Bromus tectorum in the Great Basin (Harris 1 967, Mack 1981). The literature pertaining to the emergence of natives during succession in California prairies also does not support the theory. White (1967) claimed that Stipa pulchra should be one of the climax dominants in the oak woodland at Hastings Reservation in Carmel Valley, and Burcham This content downloaded from 207.46.13.128 on Wed, 07 Sep 2016 06:03:40 UTC All use subject to http://about.jstor.org/terms 1 986] FOIN & HEKTNER: SUCCESSION IN COASTAL PRAIRIE 1 9 1 (1957) hypothesized that the same species dominated the primeval Central Valley prairies. On the other hand, Wester (1981) has used historical records to argue that perennial grasses did not dominate the inland prairies now dominated by annuals, except in wet places. Bartolome and Gemmili (1981) showed experimentally that Stipa pulchra was competitively inferior to Bromus mollis at high densities. Their evidence makes it clear that there may be great differences between species, and that being native does not necessarily confer a competitive advantage over species. Even the theoretical expectation is fragile because it was based on a number of assumptions that have been proven erroneous, the largest of which was the assumption of evolutionary advantage in a highly coevolved plant community (for a good discussion of the contribution of Clements to modern plant ecology see McMahon 1980). These arguments may be used to challenge the importance of the community in succession and to emphasize the importance of the population dynamics of key species in governing the outcome of succession (Foin and Jain 1977, Westoby 1979, Mcintosh 1981). To evaluate the dominance of versus plants in secondary succession of coastal prairie, we conducted chronosequential studies at Sea Ranch, Sonoma Co., California (38°40'N, 123°24'W) in 1974. An earlier paper (Hektner and Foin 1977) examined differences in the vegetation in different areas of the Sea Ranch coastal prairie using the data obtained in the summer of 1 974. The present paper reports the results of succession based on the 1 974 census and additional samples taken in 1975-1978. Detailed information on site conditions, species present, and land use history may be found in the 1977 paper.
The Sacramento splittail (Pogonichthys macrolepidotus) is a cyprinid fish endemic to the Central Valley of California with a range that centers on the San Francisco Estuary. It is a state Species of Special Concern and was only recently (2003) delisted as a threatened species by the U. S. Fish and Wildlife Service. Splittail live 7-9 years, tolerate a wide range of environmental conditions, and have high fecundity. Typically, adults migrate upstream in January and February and spawn on seasonally inundated floodplains in March and April. In May the juveniles migrate back downstream to shallow, brackish water rearing grounds, where they feed on detritus and invertebrates for 1-2 years before migrating back upstream to spawn. Seven long-term sampling programs in the estuary indicate that the splittail population is maintained by strong year classes resulting from successful spawning in wet years, although some spawning occurs in all years. Modeling shows them to be resilient, but managing floodplains to promote frequent successful spawning is needed to keep them abundant. Additionally, it is important to provide safe migration corridors between spawning and rearing grounds as well as abundant high-quality brackish water rearing habitat. Key research needs are (1) to examine how the timing, magnitude, and duration of high flows contribute to the generation of strong year classes, (2) to describe differences in young of year survival on the floodplain and in river margins from hatching to down-river migration, (3) explore the possible trophic effects of new invaders such as the overbite clam and Siberian prawn, and (4) determine the response of splittail populations to climate change and sea level rise.
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