Reflections on Restoration: Ten Years after Breaching of the Levees at GiacominiLorraine Parsons One of the most striking similarities between results of recent monitoring of some relatively disparate indices of ecosystem health is the sense that the restored wetland may be approaching some type of equilibrium. The initial post-restoration period was characterized by a heady, almost uniquely American sense of unlimited potential and growth. The initial cautious estimates of the wetland taking 10–20 years to evolve into a system even remotely resembling natural marshes was quickly replaced by a sense of wonderment, as thousands of waterbirds showed up in the first month after levees were breached, and salt marsh vegetation rapidly encroached into dying pasture grasses. In the first two to three years after restoration, numbers associated with all sorts of parameters kept quickly climbing—waterfowl, wading birds, invertebrates, salt marsh vegetation, tidewater goby, California red-legged frogs, native fish, special status breeding birds. The sky was, seemingly, the limit. However, much like the dot com phenomenon, these expectations quickly came down to earth. What has become evident at this intermediate restoration time period is that unrestrained growth is not sustainable, whether it be economic or ecological. Birds, fish, plant, invertebrates, all responded to the ecological promise of the restored wetland, but, eventually, newly created niches were occupied; overly abundant resources were depleted; and the wetland reached a sort of ecological status quo. One of the primary drivers of this initial ecological euphoria was really disturbance. Creation of new channels, removal of levees, scraping of pastures to create new intertidal marsh, and re-flooding of the historic wetland represent disturbance or a perturbation to the existing ecosystem. Many species, both native and non-native, take advantage of the new opportunities associated with disturbance to colonize or use these habitats. However, as species move in, conditions begin to stabilize, leading to fewer opportunities for species in the future. A perfect example of this can be found with some of the salt marsh rare plant species. Within the first few years after restoration, the extent of habitat colonized by rare marsh annuals such as Point Reyes bird's-beak and Humboldt Bay owl's-clover jumped significantly, spreading from existing seed wherever tidal waters reached. At this point, vegetation communities were in transition, with saltwater killing off former pasture grasses, which led to either bareground or sparse cover. Rare plants moved into these disturbance niches and quickly spread, with the largest acreage re-distribution occurring within 1–2 years after restoration. However, by Year 10, the spatial extent of rare plants had contracted considerably. This contraction appears to coincide with continued evolution of salt marsh plants into a more mature, densely vegetated community that leaves less room for disturbance-adapted rare annual plants. A second example would be California red-legged frog use of the newly created Tomasini Triangle freshwater marsh. As this marsh was literally excavated into former pasturelands, vegetation at the outset was limited to some perimeter plantings of emergent marsh species. Open water colonized by small, floating emergent marsh species dominated most of the marsh. However, over time, already existing stands of cattails have encroached into these open waters, making habitat less attractive to breeding red-legged frogs, as well as greatly complicating efforts to track this species. This may be why some of the best remaining habitat in Point Reyes for frog ponds tends to be agricultural stock ponds that are maintained to keep emergent vegetation at a minimum. What this means is that, somewhere between Year 5 and Year 10, the Giacomini Wetlands reached some kind of dynamic equilibrium condition. As was discussed in a previous website posting almost 10 years ago, several different models exist about ecosystem evolution. The classic Gradual Continuum Model assumes a linear model of change from disturbed condition (i.e., diked pasture) to a more natural state (e.g., tidal marsh). One of the most famous theoretical constructs of ecological change is the so-called Clementsian succession model, in which forests convert to meadow during fires and then evolve over time back to forest, the "climax" community, through successional processes. While not necessarily envisioned as a classic successional process, the evolution of the Giacomini Wetlands was anticipated to occur more or less in a linear fashion or along some type of continuum of change (i.e., A→AB→B). However, early on, it became apparent that the transition to tidal marsh would not necessarily follow this Gradual Continuum Model of habitat evolution, but more of what is being called a Threshold or Dynamic Regime Model (Hobbs and Suding 2008). While certain threshold-type models also assume progression from a disturbed condition to a more natural state with removal of disturbance factors, the progression is not necessarily assumed to be linear or to occur along a continuum of conditions. Rather, under these models, change occurs in a more discrete, step-like fashion, often with abrupt transitions between different states or conditions that require certain "thresholds" to be passed for movement from one state or condition to the next. In addition, certain perturbations can actually cause movement between states or conditions to be negative or to revert habitat back to an earlier condition. In 2009, the perturbation factor predicted to transition the wetland towards a more stable salt marsh system was high stormflow. Flooding would carve out new channels, erode old levees, and drop new sediment for rare plants and salt marsh plants to colonize. Ten years later, the Giacomini Wetlands still have yet to experience an ecosystem changer in terms of flooding. While 2017 was a very wet year, the previously dry years meant that upstream reservoirs were empty, so peak stormflow was captured behind dams and not allowed to flow down Lagunitas Creek to its wetland destination. By the time the reservoirs were full, the winter storms had eased off for the season. While disturbance is often perceived as a negative influence on ecosystem health, particularly as it can open the door to unwanted non-native plants or animals, many native ecosystems are adapted to some level of episodic perturbation or disturbance. Chaparral and some native forests require periodic fires to regenerate. Grassland health appears to be tied some level of grazing by ungulates. Based on research done in other systems, the health of tidal wetlands appears strongly associated with periodic flooding of an intensity that can widen existing channels, carve out new ones, open up vegetation canopy, and deposit new sediment for establishment of rare plants and other plants that are less able to compete in dense salt marsh communities. The importance of flooding for ecosystem development, called Flood Pulsing Theory, has been recognized both for riverine and tidal wetland systems (Middleton 2002). The lack of high-intensity flood events in Giacomini since breaching of the levees 10 years ago is driving the wetland ecosystem towards a more stable and perhaps even stagnant condition that lessens opportunities for disturbance-adapted species. This same phenomenon is observed in San Francisco Bay marshes that are highly managed or hydrologically constrained and often dominated by monocultures of either single or a few highly uber-competitive plant species such as pickleweed or saltgrass that preclude establishment of more uncommon or rare marsh plant species. Granted, disturbance can be double-edged sword, with flood flows sometimes bringing in unwanted invasives such as perennial pepperweed, as it did at Giacomini. Until more natural hydrologic, disturbance-promoting regimes can be achieved at Giacomini, the wetlands are likely to remain in somewhat of a dynamic equilibrium, with more tangible indices of wetland health such as birds, fish, and invertebrates unlikely to change unless there are some major climatic or hydrologic changes at a watershed or regional level. While numbers of birds, native fish, and benthic invertebrates may have reached a sustainable status quo of sorts, it should be acknowledged that less tangible indices of wetland health such as biogeochemical processes and nutrient cycles may be still evolving and not have reached any type of equilibrium as yet. The 15th Anniversary will be a golden opportunity to tests these theories of ecological evolution and determine how the successional trajectory for the Giacomini Wetlands is altered by external factors such as flood pulsing, sea level rise, and increases in salinity levels within Tomales Bay waters. From Pasture to Tidal Marsh: Vegetation Community Response to RestorationCody Ender1, Lorraine Parsons2, and Amelia Ryan3 
The restoration process at the Giacomini Wetlands has had a profound effect on the vegetation communities that occur within the Giacomini Wetland Restoration Project Area. Point Reyes National Seashore has monitored these changes through pre- and post-restoration monitoring that includes vegetation transects/quadrats, vegetation community mapping, and rare plant surveys. Vegetation community mapping is intended to give detailed information about the spatial representation of vegetation communities. It tells us overall acreage of different communities throughout the site, allows us to see how they are configured spatially, and shows how the spatial extent of different types of vegetation communities change over time. One of the goals of the restoration project was to see vegetation communities shift from dairy pasture to tidal salt and brackish marsh. We also hoped to see an increase in native plant-dominated communities. Before the restoration, the site was a working dairy ranch, and the project area was actively managed as pasture. Not only were tidewaters prevented from entering the site, but several active steps we taken to manage the plant community for dairy production. Palatable forage grasses such as non-native ryegrass were seeded at the site, and pastures were irrigated to keep grasses growing longer and favor certain grass and forb species. In addition, cattle-grazing itself affected plant species. The first changes at Giacomini occurred even prior to restoration when cows were removed in 2007, and all agricultural management practices discontinued. Native grasses suddenly expanded within the Project Area even without re-seeding, and lower elevation areas began to convert to diked brackish marsh. Following removal of the levees in 2008, inundation killed off many plants immediately, particularly in the northern end of the restored wetlands. After initial die-off, vegetation began to change more subtly in terms of die-off and plant establishment along elevational gradients in response to fairly consistent patterns in duration and frequency of tidal inundation. A second wave of extensive die-off occurred with build-up of salt in soils. These changes are reflected in vegetation community mapping conducted in 2009 and 2010, which documented a huge reduction in Wet Pasture by 2010 relative to 2003 (200 acres) and an associated increase in Sparsely Vegetated/Mudflat Panne habitat. While the sudden onslaught of tidal inundation initially killed all vegetation, some encroachment by salt and brackish marsh species into these barren areas had already taken place by 2010, with the amount of sparsely vegetated mudflat decreasing by 20 acres. 2018 mapping showed that salt and brackish marsh continues to increase with years following restoration. Salt and brackish marsh communities have increased 143 acres since pre-restoration mapping occurred in 2003 rising from 9% of the project area to 37%. A large portion of the increase in salt marsh can be attributed to establishment of the native California cordgrass (Spartina foliosa), which, now grows in 21% of the project area (as compared to 0.02% prior to restoration). There also was a steep decline in grassland communities and an increase in sparsely vegetated mudflat/panne immediately following restoration, changes that have persisted in the 10 years following restoration. In accordance with restoration goals, we saw non-native-dominated and mixed-nativity communities decrease (from 327 acres in 2008 to 164 acres in 2018), and native-dominated communities increase (from 80 acres in 2008 to 257 acres in 2018). This maturation of the marsh has both positive and negative aspects. The goal of the restoration project is to end up with a marsh that strongly resembles some of the natural marshes in Tomales Bay, and that appears to be occurring. However, the continued expansion of salt marsh vegetation and an increase in biomass and cover of strongly competitive marsh species such as pickleweed (Sarcornia virginica), saltgrass (Distichlis spicata), and gumweed (Grindelia stricta) means less opportunity for more uncommon or rare plant species. The number of "open" areas or canopy gaps available for new or annual species has dwindled, which is reflected in the fact that rare plant mapping shows that the areal extent of rare annuals such as Point Reyes birds-beak (Chloropyron maritimum ssp. palustre) and Humboldt Bay owl's-clover (Castilleja ambigua ssp. humboldtiensis) has actually contracted since 2012 and 2011, respectively. These species may be adapted to colonizing areas where flood-associated wrack disturbance or sediment deposition creates gaps in dense salt marsh canopies. Since the restoration, large-scale flooding has largely not occurred due to prolonged drought and capture of peak storm flows by upstream reservoirs even during wet winters such as 2017. While we still struggle with a number of weedy, ruderal species in the upland portion of the site and with several patches of perennial pepperweed (Lepidium latifolium) that have been spreading in the high marsh/upland ecotone and along Lagunitas Creek, overall, restoration has been very successful from a vegetation point of view. The site now supports a greater diversity of plant communities, the site is more similar to native reference marshes, is less weedy, and is a haven for the rare Point Reyes birds beak (Chloropyron maritimum ssp. palustre) and Humboldt Bay owl's clover (Castilleja ambigua ssp. humboldtiensis). This evidence points to significant success in restoration goals and in providing valuable habitat for wildlife. Untangling the Food Web: Changes in Prey Base Following RestorationLorraine Parsons1, Cody Ender2, and Michael Spaeth2 Tidal marsh mitigation and restoration projects are often accompanied by very quick changes in the numbers and types of mobile taxa such as birds and fish using restored tidal wetlands, with much slower changes in the invertebrate community, particularly those that burrow in the mud. However, monitoring results from 10 years after restoration of the Giacomini Wetlands shows a slightly different pattern. Point Reyes National Seashore conducted benthic invertebrate and zooplankton monitoring before restoration and for 3–5 years after restoration. Benthic invertebrate monitoring was also conducted in Year 10. Benthic invertebrates are invertebrates that live in or on marsh muds and in marsh waters: some are large macroinvertebrates such as crabs and oysters; others are almost invisible to the naked eye. These animals live at the very bottom of the marsh food chain and are typically eaten by larger organisms such as fish and birds that are, in turn, eaten by larger organisms themselves. Benthic invertebrate monitoring was designed to coincide with periods of maximum waterbird abundance, as waterbirds are large consumers of invertebrates. These waterbirds often specialize on particular prey groups. For example, among ducks, canvasback females often prefer immature aquatic insects and snails, while lesser scaups have developed specialized bills for straining small crustaceans (amphipods) from the water (Ehrlich et al. 1988). Shorebirds also have different foraging strategies based on bill size and shape, either feeding in the water or either deeply or shallowly probing the mud for snails, worms, insects, small crabs, and even small fish. Least sandpipers—one of the most common waders at Giacomini—will forage on insects in exposed or drier mudflat areas; dowitchers probe the mud in shallow water for mollusks; and greater yellowlegs feed in deeper water, snatching small fish from the water (NRCS 2000). Prior to restoration, benthic invertebrate communities in the Giacomini Wetlands differed considerably from those in natural marshes (Parsons et al. 2015), although the less distinct separation between the dairy ranch and natural marshes for zooplankton communities may have been influenced by the slight hydrologic connection between diked and undiked areas due to leaking tidegates and culverts and levee overtopping during flood events. Immediately after restoration, both the zooplankton and benthic invertebrate communities responded strongly, shifting species assemblage to the point that some convergence with communities in natural marshes was already apparent. Species richness and density of benthic invertebrates, which had both been quite low during ranching management (9.1 species and 0.15 organism/cm2, respectively), also climbed considerably, although average densities (0.99 organism/cm2) were not quite statistically equivalent with those of post-restoration undiked tidal wetlands (1.74 organisms/cm2). By Year 10, benthic invertebrate densities in the Giacomini Wetlands remained statistically equivalent between the immediate post-restoration period (first 3 years; 0.99 organism/cm2) and the intermediate post-restoration period (10 years; 1.44 organism/cm2) and were also statistically equivalent with reference wetlands 10 years later (1.71 organism/cm2). Species richness reached statistical equivalence with reference wetlands (16.5 species and 19.2 species, respectively) immediately after restoration and retained equivalence 10 years later, with Giacomini and natural tidal marshes averaging 16.7 and 15.7 species, respectively. As is obvious from the data, invertebrate densities also jumped dramatically after "restoration" in reference wetlands, as well as the Project Area, which is probably why densities were not equivalent immediately after restoration in these sampling areas. While restoration can obviously have far-reaching effects throughout the watershed—and was, in fact, intended to help improve quality and health of Tomales Bay—the largest contributor to increased average densities in natural tidal marshes came from a large increase in invertebrates in Limantour Marsh, which is outside of the direct impact area. Interestingly, a wetland restoration project was conducted in this area—removal of Muddy Hollow Pond in the upper part of the Limantour watershed—around the same time as Giacomini. Initial increases in species richness and density of benthic invertebrates did not necessarily appear to result from heavy colonization by opportunistic, often non-native polychaete species that have been found in other newly restored systems (Parsons et al. 2015), however, by Year 10, the average number of non-native species was roughly equivalent between restored (6.3 species) and reference (5.5 species) wetlands, as were benthic invertebrate densities. Multivariate analysis showed that species composition differed prior to restoration, started overlapping immediately after restoration, and then shifted again—at least for Giacomini—10 years later. This is probably due to changes in non-native species. Colonization of non-native benthic invertebrates is of concern, because it can dramatically disrupt the food web as has been seen in San Francisco Bay with the introduction of the Asian clam (Potamocorbula amurensis), which has been linked in the early 2000s with the decline of some native fish species due to decreased food supply. Even Tomales Bay has not been immune to the impacts of invasion. With the opening of the estuary lying right off one of the major shipping lanes for San Francisco Bay, organisms contained in ballast water are likely to reach its waters. While there are no definitive numbers, the recent all-taxa biological inventory in Tomales Bay found a considerable number of non-native species (TBBP 2011). However, unlike San Francisco Bay, the historical ecology of the Bay is not well known, so it is difficult to determine how much impact to the historical food web that these recent invaders have had. Some of the more well-known invasive species within the southern portion of the watershed near Giacomini Wetlands include the green crab (Carcinus maenas), signal crayfish (Pacifastacus leniusculus), and New Zealand boring isopod (Sphaeroma quoyanum). Ehrlich, P.R., D.S. Dobkin, and D. Wheye. 1988. The Birder's Handbook. Simon & Schuster, New York. 785 pp. Fish Communities in Giacomini Wetland Restoration, Tomales Bay, Marin County: 2005 to PresentMichael Reichmuth1 and Lorraine Parsons2 The composition of fish species showed strong differences between the dairy ranch and natural marshes even prior to restoration. The largest difference in these areas came from the higher relative abundances or proportion of catch of sculpin, threespine stickleback (Gasterosteus aculeatus), and non-native mosquitofish (Gambusia affinis) in dairy ranch waters, while natural wetlands appeared to have higher numbers of topsmelt (Atherinops affinis), a larger fish species (Parsons et al. 2015). Mosquitofish were probably introduced into the Giacomini Ranch drainage ditches and potentially creeks at some point by the ranchers to keep down mosquito numbers. Since then, they thrived in Project Area waters with seemingly little "maintenance" or re-stocking. After the second year post restoration, no clear differences emerged in fish community composition in the Project Area between pre- and post-restoration periods (Parsons et al. 2015). The only clear difference in relative species abundance between these periods was in the proportion of non-native yellowfin goby (Acanthogobius flavimanus) and Sacramento sucker (Catostomus occidentalis), which were more abundant prior to restoration (ibid). In general, relative abundance of non-native fish and invertebrate species, including relative abundances of mosquitofish, yellowfin goby, cheekspot goby (Ilypnus gilberti), silver carp (Hypophthalmichthys molitrix), white crappie (Pomoxis annularis), and signal crayfish (Pacifastacus leniusculus), dropped considerably immediately after restoration (ibid). Fish composition of the restored wetlands also continued to differ strongly from natural marshes even several years after restoration. Natural marshes supported more arrow goby (Clevelandia ios), goby and longjaw mudsucker (Gillichthys mirabilis), while Giacomini had higher relative abundance of sculpin and bay pipefish (Syngnathus leptorhynchus; ibid). By Year 10, some of the trends observed immediately after restoration continued to develop, with further decreases in non-native fish species richness and abundance of certain species. Mosquitofish dropped from 20% of the fall catch prior to restoration to 1% after restoration, and yellowfin goby went from 5% of the summer catch pre-restoration to 2% post-restoration, although numbers appeared to increase again in 2018 (Reichmuth 2018). Numbers of arrow goby and topsmelt—two of the species strongly associated with natural marshes prior to restoration—jumped dramatically by Year 10 (ibid). Threespine stickleback (Gasterosteus aculeatus) remained, however, the most common species caught in either summer and fall both prior to and after restoration (ibid). Total catch of native and non-native fish species climbed sharply in Year Two after restoration (2010) with more than 7,000 fish caught in summer sampling event, but numbers have declined since then, with catching consistently hovering around 4,500 individuals (ibid). This same leveling-off effect does not appear to be occurring with total species richness, as the total number of fish species caught has climbed slightly from 40 species in 2009 to more than 50 species in 2018 (ibid). Ultimately, composition of the Giacomini Wetlands and natural marsh fish communities may never totally converge, because the Project Area will continue to be influenced much more strongly by freshwater from creek flow and abundant groundwater flow from the surrounding Point Reyes Mesa and Inverness Ridge than any of our reference wetlands (Parsons et al. 2015). Threespine stickleback can occur across a range of salinities, but its abundance is typically highest in freshwater and brackish environments, while arrow goby predominates in more saline environments (ibid). Threespine stickleback occur in much lower numbers in natural marshes, probably because of the higher range of salinities in this Study Area (ibid). Numbers of tidewater goby (Eucyclogobius newberryi), a federally endangered brackish water fish that occurred in the Project Area even prior to restoration, did not appear to change immediately with restoration, and, in fact, relative abundance might have been highest actually during the period when dairy ranching was discontinued, but levees weren't breached: In 2007, more than 300 tidewater goby were found (Reichmuth 2018). During construction, some of the restoration effort focused on protecting existing goby habitat. However, in October 2009, fisheries biologists actually found tidewater goby already using some of the newly restored tidal creek habitat, well ahead of the expected timeline for colonization of these new habitat areas. Despite expansion of habitat, overall numbers of goby were still quite low in 2009 (~25 fish; ibid). They remained low until 2011, when goby suddenly moved into the mainstem Lagunitas Creek channel: the fall sampling event captured more than 150 goby, most of which were found in Lagunitas Creek (ibid). Subsequent sampling events in 2012 and 2013 continued to find this species, although seemingly at lower abundance. There was no additional sampling until 2018, when fish monitoring found no goby in either the summer or fall sampling events. While some annual variability in numbers might be expected with this short-lived species—it, after all, remained undetected for almost 50 years in the Tomales Bay watershed until baseline surveys for Giacomini re-discovered it in one of the diked creeks in the dairy ranch—the failure to capture any goby during the 2018 season is concerning. Park biologists will be developing a plan to conduct more detailed sampling for this species starting in fall 2019. Parsons, L., L. Sanders, A. Ryan, and M. Reichmuth. 2015. Changes in the Food Web Linked to Restoration Effort Intensity and Watershed Conditions. Natural Resources. 6:344–362. (accessed 14 December 2018) Giacomini Marsh Wetland Restoration Avian Monitoring 2009–2018Jules Evens and Mary Anne Flett Waterbird numbers grew sharply in the initial years following restoration, with a record high number of approximately 16,000 waterbirds counted on one day in December 2013 (ARA 2018a). However, waterbird numbers started tapering off in 2014/2015, and numbers remained similar during the most recent monitoring in 2017/2018. Since restoration, two species of surface-feeding ducks—green-winged teal and American wigeon—were the most abundant, accounting for 43.3 percent of all waterbirds present (Sept–Feb; ARA 2018a). It is possible that reduced waterbird numbers at Giacomini reflect the influence of other tidal wetland restoration projects in San Francisco Bay, which may be changing regional migration patterns by increasing the number of foraging locations available (J. Evens, ARA, pers. comm.). Another possibility is that resources were depleted by the early abundance of waterfowl (ibid). While overall waterbird numbers remained seemingly static over the last three years, total wader numbers increased as a percentage of all detections during the winter period from 11.5 percent in 2014–15 to 29.5 percent in 2017–18. Winter waders were dominated by calidrines, especially the least sandpiper which represented 27.3 percent of all waterbird observations and 65.1 percent of all waders (ARA 2018a). Immediately after restoration, shorebird numbers were low in the first winter, moderate in the second year and first half of the third year, and then declined sharply in the latter half of the third year (ARA 2012). In Year 4, shorebird numbers rebounded to approximately Year 2 levels (ARA 2012). These trends suggest that Giacomini is continuing to evolve as potential shorebird habitat, with this evolution strongly dependent on invertebrate prey bases in marsh muds. In the early years, the restored wetland primarily attracted species that forage in the water column, ground, and in shallow sediments (J. Evens, ARA, pers. comm.), however, the arrival in fall 2011 of marbled godwits and wowitchers, which forage more deeply in muds, may have been yet another confirmation of what we have observed through our benthic invertebrate and zooplankton monitoring results—numbers of benthic invertebrates in the restored wetlands have climbed dramatically, and species composition has shifted. (See accompanying summary of changes in benthic invertebrate community: Untangling the Food Web: Changes in Prey Base Following Restoration.) The increase in available habitat and food sources for shorebirds has had a positive effect not just on Giacomini, but the entire southern portion of Tomales Bay. (See accompanying summary on this phenomenon in "Tidal Marsh Restoration Stimulates the Growth of Winter Shorebird Populations in a Temperate Estuary."). As with waterbirds, densities of spring breeding birds increased following restoration, particularly for some of the wetland-dependent passerines. Overall, species richness was highest in Year 2, while the total number of observations was actually highest in Year 4 (ARA 2018b). Approximately 280 observations were made in 2009, compared to 430 in 2010, 413 in 2011, 484 in 2012, 399 in 2013, and 398 in 2018 (ARA 2018b). The number of species detected has remained relatively consistent, ranging from a low of 66 in 2012 to a high of 82 in 2010 with most years averaging around 70 species (ARA 2018b). Of the wetland associates, all except red-winged blackbird showed population increases; both riparian associates showed increases, and of grassland/upland associates, abundance values of goldfinches were essentially stable, whereas Savannah sparrows declined (ARA 2018b). Most emblematic of the restoration of tidal marsh habitat was the recolonization of the historic wetlands by the California black rail, a state "threatened" species. Detections of this furtive marsh bird 2016–2018 indicate that a nesting population has occupied approximately 10 hectares of newly established salt marsh habitat seven years after the reintroduction of tidal influence (ARA 2018b). Avocet Research Associates (ARA). 2012. Giacomini Marsh Wetland Restoration Avian Population Surveys: Post-Restoration Avian Population Surveys. Winter Season Year-4 2011–2012. Final report to Point Reyes National Seashore, National Park Service. Tidal marsh restoration stimulates the growth of winter shorebird populations in a temperate estuaryJohn P. Kelly and T. Emiko Condeso The regional responses of winter shorebird populations in the nearly 3,000 ha estuary of Tomales Bay, California, to the restoration of 223 ha of historic tidal wetlands were evaluated for 27 years: 19 years prior to tidal reintroduction and 8 years after tidal reintroduction. We used interrupted time series analyses to measure the spatial extent of the restoration effect and to model the magnitude and length of time associated with the gradual, restoration-induced growth of winter shorebird populations in the bay. Expanded, regional benefits of the restoration were revealed by consistent patterns of winter shorebird population growth. Eight years after tidal reintroduction, overall shorebird abundances in southern Tomales Bay nearly tripled in response to the restoration. Substantial winter population growth by most species in southern Tomales Bay was evident within 3 years after tidal reintroduction, and maximum responses to the restoration were estimated to be predominantly achieved within 8 years. In contrast to strong effects of tidal marsh restoration on winter shorebird populations in southern Tomales Bay, no significant overall responses were exhibited by shorebirds in the northern portion of the bay, although marginal evidence of expanded effects on a few species in northern Tomales Bay were suggested. The results illustrate the importance of accounting for restoration effects beyond the spatial and temporal boundaries of the restored habitat, to consider both the potentially expanded benefits and the spatial limits of those benefits to regional wildlife populations. The summary above is the abstract for: Build It and They Will Come: California Red-Legged Frog Use of Restored WetlandsAlexa Killion and Patrick Kleeman While the Giacomini Wetland Restoration Project was intended to convert the former dairy ranch back into tidal wetlands that once existed there previously, there were a number of threatened and endangered freshwater marsh and brackish marsh species that had taken up residence within the pastures and associated aquatic habitats such as drainage ditches, ditched creeks, hunting ponds, and remnant freshwater marshes. During baseline surveys conducted in the 1990s, the federally threatened species, California red-legged frog (Rana draytonii), was found in a freshwater marsh area along the western edge of the ranch north of Inverness Park. This population was sizeable, supporting as many as 80 breeding frogs at one point. As hydrodynamic modeling indicated that this marsh would convert to brackish or even saline habitat with removal of levees and reintroduction of tidal flow, the National Park Service worked with U.S. Geological Survey biologists to identify some potential measures for mitigation of these impacts. As part of these efforts, freshwater ponds and marshes were designed in areas that hydrodynamic modeling determined would not be impacted by tidal influence after restoration: At Point Reyes National Seashore, eggs surviving to hatching have not been observed in water with a salinity > 2.0 ppt (P. Kleeman, USGS, pers. comm. in Baylands Ecosystem Habitat Goals Science Update (2015)), and adults typically do not occur in water with salinity levels greater than 7.0 ppt (Hennings and Jaye 1990). Four mitigation features were created: one on the eastern edge of the Giacomini Ranch near Point Reyes Station (Tomasini Triangle Marsh); two just east of Olema Marsh (Olema Creek Frog Ponds North and South); and one on the western side of the ranch near Inverness Park (Lucchesi Pond). USGS biologists Gary Fellers and Patrick Kleeman have been monitoring frog populations in the Giacomini Ranch since the project was first initiated. California red-legged frogs were not found at Tomasini Triangle Marsh until 2010, three years after creation of the marsh, but have been present in varying numbers since then (Killion and Kleeman 2018). Peak numbers of CRLF were seen in 2013 with 59 adults in the winter and 80 subadults in the summer, demonstrating good reproductive success (ibid). Fewer adults were seen in the winter of 2018 (14), with up to five (5) egg masses observed, but no sign of successful breeding was found during the summer surveys (ibid). Numbers were much lower at the Olema Creek Frog Ponds, with a maximum of one (1) to two (2) adults, one (1) egg mass, and no juveniles detected (ibid). No CRLF were observed at the Lucchesi Pond. Meanwhile, some remnant freshwater features such as the Lucchesi Drainage continue to support small, but consistent populations of red-legged frog (ibid). The decline in CRLF numbers in recent years follows a trend that has been seen at many newly created ponds in the San Francisco Bay area: CRLF often colonize ponds soon after pond creation if there is enough vegetation to provide cover for adults and sites for them to attach their egg masses (Killion and Kleeman 2018). These early years often have high numbers of adults followed by fewer adults in subsequent years as the sites become more vegetated (ibid). Visual detectability of all life stages of CRLF becomes more difficult as vegetation becomes denser at sites, but this probably does not completely account for fewer CRLF seen at these sites (ibid). While it may be disconcerting to find lower numbers of CRLF over a span of years, it's important to note that persistence of CRLF at any given site may be more important from a meta-population perspective than variable yearly counts of individuals (ibid). Allen, S. and P. Kleeman. 2015. Baylands Ecosystem Habitat Goals Science Update (2015). www.baylandsgoals.org Page 1 of 8 Science Foundation Chapter 5. Appendix 5.1 – Case Study of California Red-Legged Frog (Rana draytonii) |
Last updated: April 25, 2024