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HomeMy WebLinkAbout; Coastline of North Carlsbad Resouces; Coastline of North Carlsbad Resouces; 2000-03-31OBSERVATIONS ON THE STATUS OF BIOLOGICAL AND PHYSICAL INTERTIDAL RESOURCES ALONG THE COASTLINE OF NORTH CARLSBAD for The City of Carlsbad Carlsbad, CA 92008 by Coastal Environments 2166 Avenida de la Playa "E" La Jolla, CA 92037 (858) 459-0008 March 31,2000 CE REFERENCE NO. 00-07 Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad TABLE OF CONTENTS Section TABLE OF CONTENTS i LIST OF PHOTOGRAPHS ii EXECUTIVE SUMMARY iii 1. INTRODUCTION 1 2. BACKGROUND 1 3. HABITAT TYPES 4 3.1 Surfgrass (Phyllospadix spp.) 4 3.2 Feather boa kelp (Egregia menziesii) 4 3.3 Southern Sea Palm (Eisenia arbored) 4 3.4 Giant Kelp (Macrocystispyriferd) 5 4. INTERTIDAL 5 4.1 METHODS 5 4.2 OBSERVATIONS 5 5. CONCLUSIONS 7 6. RECOMMENDATIONS 8 7. LITERATURE CITED 8 APPENDIX A PHOTOGRAPHS A-l APPENDIX B SURVEYS B-l Coastal Environments CE Reference No. 00-07 Technical Report Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad LIST OF PHOTOGRAPHS Photographs are presented in Appendix A. Photograph No. Description 1. 2 3a. 3b. 4a. 4b. 5a. 5b. 6a. 6b. 7a. 7b. 8a. 8b. View of the beach extending north from a location below the Carlsbad parking lot located between Oak and Pine streets, 1/21/2000. View of the beach extending south from a location below the Carlsbad parking lot located between Oak and Pine streets, 1/21/2000. View of the rocky intertidal reef located slightly south of the northernmost stairway to the beach walkway, 1/20/2000. View of one of the larger rocks in the rocky intertidal reef located slightly south of the northernmost stairway to the beach walkway, 1/20/2000. View of the rocky intertidal reef located below and slightly south of Beachwalk Access Stairway 2 (numbered from the north) looking south, 1/21/2000. Part of one of the rocks in the rocky intertidal reef located below and slightly south of Beachwalk Access Stairway 2, 1/21/2000. View of the rocky intertidal reef located below and slightly south of Beachwalk Access Stairway 3 (numbered from the north) looking south, 1/21/2000. Part of one of the rocks in the rocky intertidal reef located below and slightly south of Beachwalk Access Stairway 3, 1/21/2000. View of algae on one of the scattered rocks comprising the intertidal reef below Beachwalk Access Stairway 4 (numbered from the north), 1/21/2000. Surfgrass on the rocky intertidal reef located below Beachwalk Access Stairway 4, 1/21/2000. View of part of the submerged rocky intertidal reef located below Beachwalk Access Stairway 5 (numbered from the north), 1/21/2000. Surfgrass on the rocky intertidal reef located below Beachwalk Access Stairway 4 (numbered from the north), 1/21/2000. View of one of the higher rocks in the rocky intertidal reef located below the Tamarack parking lot, 1/21/2000. Rocky intertidal reef located below Tamarack parking lot, 1/21/2000. Coastal Environments CE Reference No. 00-07 Technical Report Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad EXECUTIVE SUMMARY The purpose of this study is to provide new information useful in the determination of whether there are biological or physical resources present along the coast that preclude the addition of sand for beach replenishment on north Carlsbad beaches. Qualitative observations of the intertidal rocky reefs along the north Carlsbad coastline were taken during January and February 2000 to document the location and type of intertidal biological resources, show whether the resource is likely to be present long-term, and evaluate whether placement of sand will impact jj existing biota considered important. In addition, a survey of the shallow subtidal area offshore *—' this coastline was done earlier using side-scan sonar to identify subtidal areas of hard bottom and bathymetry (water depth) to evaluate height of rocky areas above the sea floor. The presence of offshore rocky areas is important as those with relief between 1 and 3 feet may support sensitive species that could be at risk to sand that was moved offshore by wave action after placement on the beach. The north Carlsbad coastline surveyed stretches from Oak Street south to the north jetty for Agua Hedionda Lagoon. Seven rocky intertidal areas were visible during the low tides during these surveys. These were sampled by a biologist who took observations, video, and photographs. The field observations, information extracted from the videos, and resources shown on the photographs were combined into the report. The rocky areas were comprised primarily of low-relief rocks (<1 foot above the surrounding M sand) with either no algal cover or with short algal forms such as erect coralline algae to 2 inches *—' high) or the brown alga Zonaria farlowii. These areas and their attached biota are adapted to occasional cover by sand in this dynamic environment. The rocky area located below the third stairway from the street to the Carlsbad beach walkway had a few rocks with relief up to 1.5 feet. These rocks also supported coralline algae and Zonaria farlowii. Surfgrass was present on several reefs in the area south of the fourth stairway from the north. There was a little attached surfgrass on the rocks further offshore of this stairway. These rocks had a higher relief than the others comprising this reef. Surfgrass was present on the two southern reefs, one below Stairway 5 and the other approximately 150 feet north of the north jetty for Agua Hedionda Lagoon. These beds were dense and extended a considerable distance offshore. Because this area was in the surfzone when observations were taken, an accurate estimate of the rock height was not obtained. The later observations showed that the sand beach extended to the inshore edge of the surfgrass and that there was a considerable amount of sand around the bases of the plants. When evaluating the impact of sand replenishment, it is important to consider that all of the plants normally found within the intertidal zone in the study area are adapted to withstand the constant movement of sand. Surfgrass, for example, was consistently found with the bases buried. In several places, it was nearly covered with only a few inches of its bright green leaves Coastal Environments iii Technical Report CE Reference No. 00-07 Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad extending above the sand. Since it can receive nutrients from the water column through the leaves, it may be able to withstand a considerable amount of burial (both thickness of sand and period of cover) before dying. Feather boa kelp, another important species, is a brown algae fairly closely related to giant kelp. It has a small holdfast that is attached to rocks and was found attached to rocks close to sand. These results suggest that prudently placed sand (location and thickness) should not cause serious environmental impact to the important biota in the intertidal. This habitat is characterized by considerable natural movement of sand and a biota adapted to survive the perturbations caused by this movement. Surfgrass, probably the most abundant of the important intertidal biological resources and one of considerable concern, was present in intertidal areas located primarily south of the fifth stairway from the north. Sand was usually present around its ^ bases ranging in thickness from a thin layer to 6 or more inches, yet surfgrass was apparently healthy. As the surfgrass was able to survive a range of depths of sand burial, this suggests that surfgrass will be able to survive the impact of additional sand added to the beaches as long as it is not placed directly on or above it. 11 Several of the Carlsbad intertidal areas north of Stairway 4 are likely to be impacted by the addition of sand, as well as prolonged periods of weak swells and waves (commonly in the summer), because the reefs have low-relief and are located in depressions with an offshore sand bar. As these areas are at risk during natural conditions and did not support surfgrass or sensitive algal resources, it is likely that cover by sand of these intertidal areas would not be considered a problem. The areas south of Stairway 5 do raise a concern if there is significant lateral movement of sand that could accumulate north of the jetty. The areas observed during this study appeared to have low relief, but supported surfgrass. It became apparent during the visits during February that this surfgrass was being encroached by the existing sand on the beach. The surfgrass would not be affected by additional sand that raises the beach height a few inches, but a foot would cover the intertidal surfgrass observed during this survey. A baseline component of a monitoring program that follows this area of surfgrass will show whether this area becomes buried naturally during prolonged periods of low wave action (usually summer). If sand were placed on the beach without this baseline information, the resource might be considered damaged and require mitigation even if it were covered by sand by normal onshore-offshore movement of sand. Coastal Environments - iv Technical Report CE Reference No. 00-07 Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad STATUS OF BIOLOGICAL AND PHYSICAL RESOURCES ALONG THE COASTLINE OF NORTH CARLSBAD 1. INTRODUCTION A survey was done to document the location and type of biological resources present along ^ the Carlsbad coast, and show whether the resources are likely to be present long-term. The purpose of this qualitative study is to provide new information useful in the determination of whether there are biological or physical resources present along the coast that preclude the addition of sand for beach replenishment. The survey incorporates the following components. • Assessment of intertidal hard bottom areas by biologists • Side-scan/sub-bottom profiles to identify subtidal areas of hard bottom and some evaluation of their elevation above the sea floor • Assessment at low tide of the low intertidal/shallow subtidal areas that are not normally visible in the intertidal or in the side-scan/sub-bottom profiles. fj Observations made during surveys of the intertidal rocky (hard bottom) reefs done during '-' early 2000 are presented in this report along with the results of offshore side-scan and bathymetry surveys. 2. BACKGROUND The beaches along southern California have diminished in width and elevation in recent years due to lack of sand resources to naturally replenish sand lost to the natural processes of sand movement. Sand normally moves onto the beach in the summer and off the beach to subtidal areas in the winter. In addition there is a general downcoast (southward) movement due to predominant southward littoral currents in the Oceanside Littoral Cell. The onshore-offshore movement of sand often results in a net loss of sand because some sand may be moved further offshore in winter than can be moved onshore during the summer. This results in a net loss of beach sand and a build up of sand in some offshore areas. The largest loss of sand, however, is ,—, due to the general downcoast (southward) movement by currents. Downcoast sand movement often is stopped by coastal barriers such as jetties or eventually lost into nearshore deep water canyons such as Carlsbad Canyon and Scripps Canyon. Thus, sand on the beaches is eventually lost, either to offshore sand deposits or to deepwater canyons. This means that the sand has to be replaced at the same rate of loss or the beaches will diminish in size. This is what has happened and is caused by a decrease in the sources and amount of sand coming to the beaches. Original sources of sand were the drainages from constantly flowing terrestrial water sources (rivers, creeks,, streams), episodic periods of runoff Coastal Environments 1 Technical Report CE Reference No. 00-07 0 Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad from these water sources as well as from areas that normally are dry, and nearshore cliff erosion. Dams, flood control projects, and concrete channels have dramatically decreased the amount of sand coming from the upland terrestrial sources. Projects are continuously attempting to stop nearshore cliff erosion. The net result is that little sand is available to replenish the beaches. Thus, sand for beaches comes primarily from the normal onshore-offshore cycle and from sand transported from upstream (generally northern) beaches by littoral currents. As discussed above, these sources have a net loss, thus the beaches have decreased in amount of sand. The decrease in sand has resulted in physically lower intertidal (areas of the beach exposed during the period between high and low tides) and nearshore subtidal (areas offshore of the beach that are never exposed, even at the lowest of tides) areas. Thus, areas that in the past had a sand bottom with underlying rock that was occasionally exposed, now may have rock that is continuously exposed. Rock, or hard bottom, is more highly valued as a substratum for biota. This is because it is less common than the sand bottom in intertidal and nearshore areas in southern California and it supports a more visible and three-dimensional biota that is important as food, nursery, and refuge. Thus, these areas then fit under the National Marine Fisheries Service (NMFS) Habitat Protection Policy (NMFS 1991) specifically the following. "The Southwest Region of NMFS will not recommend approval or authorization of any project or activity that will damage any existing or potentially restorable habitat of living marine, estuarine, or anadromous resources." The NMFS does have processes that will allow a project to proceed that will damage the habitat. These processes require some type of compensation or mitigation. These can require an expenditure in addition to the project and in recent mitigation projects for damages much larger in scope than beach replenishment have resulted in a large habitat restoration project in Batiquitos Lagoon and habitat enhancement by building an artificial reef off San Clemente, California. "Under circumstances in which habitat/resource damages can be compensated, exceptions to the policy may be allowed. The following conditions are required for such exception: 1. The project will incorporate all feasible modifications and construction techniques to minimize adverse environmental impacts. 2. For adverse environmental impacts that cannot reasonably by eliminated by project modifications, an acceptable combination of habitat restoration, enhancement, or other suitable mitigation will be adopted." Rock areas (both intertidal and nearshore subtidal) with low elevation above the surrounding sand are covered and uncovered by natural sand movement processes each year. This elevation above the sand has been selected as <1 foot. In addition, areas of high relief, selected as >3 feet above the surrounding sand are not considered to be at risk to cover by sand if the amount of sand to be placed on the beach is expected to increase the beach height by approximately 1 foot. Coastal Environments 2 Technical Report CE Reference No. 00-07 Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad Several intertidal and subtidal areas along the Carlsbad coastline have been reported as between the 1 and 3 foot heights with a biota attached that has been considered important. Thus, the following needs to be considered. • Is it important to put sand on the beaches? • If so, is compensation/mitigation needed? • Are there rocky areas that presently exist along this coastline that are at risk? • Do these rocky areas support a community that would be at risk due to occasional cover by sand? • Do these rocky areas support a community that would be at risk due to prolonged/permanent cover by sand? An increase in sand on the beaches should provide an additional buffer for protection of the bluffs along the coast. The decrease in the sand level has led to more direct wave action against the cliffs as the higher elevation of sand there previously helped to dissipate some of the wave energy before it reached the cliffs and may have stopped some waves from reaching the bluffs. In addition, areas of the cliffs that had previously had sand covering their bases may be more prone to erosion by the direct wave action because this area of the cliff has not recently experienced these forces. Therefore, adding sand to these beaches may result in some protection (I for the bluffs. Additionally, a higher elevation of sand along the bluffs will provide more useable '-' beach space for beach visitors. According to the NMFS policy (NMFS 1991), mitigation or compensation is the technique to allow projects to continue if techniques are used to minimize adverse environmental impacts. The agencies' concerns about sand replenishment in this area have, in the past, primarily concerned the loss of valuable rock habitat. As bottom configurations change constantly due to wave action, sand movement, etc. the present status of the habitats in the area of concern should be known to provide the best assessment. Some of the area was surveyed for the beach replenishment component of the Navy's homeporting project for aircraft carriers in San Diego Bay. These surveys were done primarily in winter 1996 with some possibly in 1997. Observations indicated that "this beach segment consists of a predominantly flat sandy beach, extending from the surf line to rip-rap slopes and sea walls." This survey has several components, one of which is to conduct a physical survey that will identify the bottom types present in the subtidal areas offshore of the Carlsbad coastline. P, " A second component of this survey is to look at the areas identified as hard bottom, particularly those shown to have a moderate elevation above the surrounding sea floor, to qualitatively evaluate and document what biota are present. Coastal Environments - 3 Technical Report CE Reference No. 00-07 Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad 3. HABITAT TYPES 3.1 SURFGRASS (PHVLLOSP/ID/XSPP.) The surfgrass along this coastline is comprised of two species, Phyllospadix scouleri and P. torreyi. Phyllospadix is generally found slightly deeper than coralline algae and restricts the distribution of coralline algae (en sensu Stewart 1989) in the intertidal zone. Surfgrass can also extend offshore to depths of approximately 20 feet (Dawson and Foster 1982). Several authors have indicated that surfgrass would exclude coralline algae in the mid-intertidal zone, if it were not removed by winter storms in the shallower areas (Dethier 1984); (Turner 1985). The Phyllospadix species are distinguished by the shape and diameter of the leaves, the number of reproductive structures, and usually by the location in the intertidal. Phyllospadix torreyi has narrow leaves (1-2 mm) that are elliptical in cross section and several spadices at the end of long flowering stems (Dawson and Foster 1982). According to (Dawson and Foster 1982), it is most common in protected sandy areas. Phyllospadix scouleri has broader leaves (2-4 mm) that are flat, one or two spadices at the end of short flowering stems, and is most abundant attached to PI rocks in areas of heavy surf (Dawson and Foster 1982). In Baja California where both species M were found, P. scouleri had its maximum biomass higher in the intertidal than P. torreyi (Ramirez-Garcia 1998). Phyllospadix spp. Watson ('surfgrass') is one of very few seagrass species that grow on rocks. Thus, unlike most other seagrasses, nutrient uptake is across leaves rather than across roots might be very important for nutrient acquisition. Low NH4+ uptake rates by roots (<0.2 umol N g dry wt-1 h-1) suggest that surfgrass acquires most of its nitrogen via its leaves (Terrados and Williams 1997). This along with the compact cross-section of the leaves of the plant may help explain its ability to withstand some sand cover over the bases of its plants. 3.2 FEATHER BOA KELP (EGREGIA MENZIESII) Egregia menziesii is a fast growing brown algae (kelp) that attaches to rock and inhabits mid- intertidal to subtidal areas (60 feet) in southern California in protected to moderately exposed areas (Abbott and Hollenberg 1976). It is characterized by a thick mid-rib with leaves branching from the mid-rib. This looks like a 'feather boa,' thus its common name. It commonly forms thick patches in the deep intertidal and shallow subtidal. 3.3 SOUTHERN SEA PALM (EISENIA ARBOREA) M Eisenia arborea is also a brown alga that attaches to rock (Abbott and Hollenberg 1976). It belongs to the same taxonomic family as the feather boa kelp, but is a much smaller plant than the feather boa. It has a thick stipe that is approximately one foot tall. At the top, the stipe branches into two parts, each supporting numerous leaves. It occasionally forms moderately dense groups of plants in the shallow subtidal and occasional single plants are found in the intertidal. Coastal Environments 4 Technical Report CE Reference No. 00-07 Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad 3.4 GIANT KELP (MACROCYSTIS PYRIFERA) ,—I This is a brown algae found in subtidal areas. It is fast growing and produces very large plants. While the number of plants in an area may not be large, older plants form a canopy as the tops of the plants float on the surface of the water and spread out, often appearing to completely cover the water surface. Areas where these plants produce a canopy are referred to as 'kelp beds' or 'kelp forests' and usually are present for a number of years. While these areas appear to be continuously present in the same location, there are commonly changes in where the plants are present as old plants die, are removed by storms, or float away if they become too big for the rock they are attached to. If conditions are acceptable, young plants grow where there is adequate light, often not beneath the old canopy, and produce a canopy, often not quite in the same location as the old canopy. Because of the shading effect of old plants, rock often needs to be disturbed to make new space available for kelp plants to colonize. Different types of disturbance have been shown to open up new space including storm effects that remove plants, plants that become too buoyant for their attachment and float away, and covering and uncovering of rock by sand. 4. INTERTIDAL The intertidal from north of Oak Street to the north jetty of the mouth of Agua Hedionda Lagoon was surveyed during the low tides on January 20 and 22, 2000 and observations on selected areas taken on February 16 and 18, 2000. Because the areas of low intertidal are visible only during very low tides, this period provided a very good opportunity to view the low intertidal. 4.1 METHODS Sampling for the intertidal component of the survey was comprised of the following. • Video of beach areas • Still photographs of rocky intertidal areas • Beach width estimates from the base of the sea wall to rocky areas • Beach width estimates from the base of the sea wall to areas with surfgrass • General biological observations 4.2 OBSERVATIONS The observations will be presented starting at the north end of the area observed moving toward the south end. Written descriptions are supplemented with photographs. R Initial observation during low tide on January 20th from the beach below the parking lot '—' located between Oak and Pine Streets showed that no intertidal rocky areas were visible north of Pine Street (Photograph 1), but several rocky areas were visible south of Pine Street (Photograph Coastal Environments 5 Technical Report CE Reference No. 00-07 Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad 2). Thus, the majority of time was spent taking observations south of Pine Street. Description of the location of rocky areas observed is oriented to the stairways leading to the Carlsbad Beachwalk from Coast Drive. The northernmost stairway was designated as ' 1' and each one further south was increased by increments of one. Approximately 50 feet south of Stairway 1 was a rocky outcrop with a sand bar offshore (Photograph 3a). Biota on the rocks included crustose coralline algae (generally pink algae that form a flat crust on the rock), a little erect coralline algae, and some small barnacles (Photograph 3b). It extends to about 75 feet north of Stairway 2. Approximately 50 feet south of Stairway 2 were some finger reefs with red algal turf and few larger plants (Photograph 4a). One area did have some small mussels (about 1/4 inch long) and some crustose coralline algae (Photograph 4b). This area was estimated to extend 200 feet along the shore. A third rocky area was present below Stairway 3 (Photograph 5a). This appeared to be the largest rocky intertidal area along the north Carlsbad beach. As with the two northern reefs, it had a sand bar offshore of the rocks and sand bars to the north and south, thus, surrounding the rocks with sand. Red algal turf was present on the rocks on the north end. Approximately halfway to Stairway 4 there were a few rocks with higher relief (up to approximately 1.5 feet above the sand at their base). These rocks supported erect coralline algae and the small brown alga Zonaria farlowii (Photograph 5b). These algae covered approximately 40 to 50% of the rock surface with corallines being more abundant. The remainder of the rock surface was primarily covered with sand and some red algal turf. Stairway 4 also had a rocky area below it and to the north of it. The rocks closest to the beach were low and had red algal turf and Zonaria farlowii growing on them. Some areas also had high percentages of erect coralline algae (Photograph 6a). Both types of algal cover had considerable sand on the rocks. The rocks further offshore had a higher relief with a little attached surf grass (Photograph 6b). Just north of Stairway 5 there is an area with low rocks covered with a thin layer of sand and Zonaria farlowii. The edges of these rocks also supported erect coralline algae. Below Stairway 5 is a rocky reef that starts approximately 150 feet from the seawall for the walkway (Photograph 7a). There is a dense patch of surfgrass on these rocks that extended approximately 50 feet offshore (Photograph 7b). Because this area was in the surfzone at the time of observation, an accurate estimate of the rock height could not be obtained. There is another rocky area approximately 150 feet north of the north jetty for Agua Hedionda Lagoon and 75 feet south of the end of the seawall for the walkway (Photograph 8a). This area is very low intertidal, perhaps more shallow subtidal. It supports a fairly large and dense patch of surfgrass (Photograph 8b). There was no intertidal rocky area between the jetty and this rocky area. Coastal Environments 6 Technical Report CE Reference No. 00-07 D D Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad 5. CONCLUSIONS The qualitative observations of the Carlsbad intertidal taken during this survey from the north of Oak Street to the north jetty of Agua Hedionda Lagoon mouth showed that there are several rocky areas within this stretch of coast. Most are comprised of low-relief rocks (<1 foot above the surrounding sand) with either no algal cover or with erect coralline algae or the brown alga Zonaria farlowii. These areas are adapted to occasional cover by sand in this dynamic environment. There are only a few rocky areas that had higher relief during this survey. The area off Stairway 3 had a few rocks slightly higher than 1 foot above the sand at their base. These rocks supported erect coralline algae and the small brown alga Zonaria farlowii. The rocky areas below Stairway 5 and north of the jetty were not measured but also may have higher relief. These areas supported surfgrass in the lower intertidal. One other area had a small patch of surfgrass. This was on low-relief rocks below and north of Stairway 4. All of the plants normally found within the intertidal zone are adapted to withstand the constant movement of sand in this zone even though they are attached to rocks. Surfgrass, for example, was consistently found with the bases buried. Since they can receive nutrients from the water column through their leaves, they may be able to withstand a considerable amount of burial before dying (I could find no literature that addressed this issue). Also important is whether their haptera or holdfast survives burial for prolonged periods of time even if the leaves have dropped off. Again, I could find no literature addressing this important aspect of surfgrass biology. Feather boa kelp, another important species, is a brown alga that is fairly closely related to giant kelp. It has a small holdfast that is attached to rocks. Throughout this intertidal area, it was found attached to rocks close to sand. Plants were also found with holdfasts completely buried, yet the plants appeared to be in good health (proper color). As this species is commonly found in the lower intertidal and shallow subtidal, it is undoubtedly better adapted to some sand burial than giant kelp which can withstand only short periods of burial of its holdfast. Some observational information supports the idea that surfgrass may be able to re-establish itself fairly quickly following accretion and erosion of sand on rocky surfaces. Recently (one to two years ago) sand was placed on the beaches north of the jetty. This sand apparently covered some of the surfgrass area near the Tamarack Beach surf area (the southernmost area where we observed surfgrass). After the sand eroded, surfgrass was present on the rocks in a short period of time (perhaps 4 months). Unfortunately, this information is not documented and is based on the recollection of surfer (also a trained biologist) that frequents the area, so it has little value in dealing with the resource agencies. Coastal Environments 7 Technical Report CE Reference No. 00-07 Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad 6. RECOMMENDATIONS The addition of sand will benefit the beaches along the coastline, and prudent placement of the sand should result in no significant impact on the biota inhabiting the rocky areas. This can be documented by a monitoring program, which should include an intertidal component, as well as beach profile, subtidal reef, and giant kelp components. This is necessary to ensure that resources are being protected, and to verify the computer model used to determine where and how much sand could be placed. To evaluate whether the resources are being protected will require monitoring rocky areas both within and outside the projected area of potential impact. This is necessary to help evaluate the impact of sand placement by providing information that can be used to account for other environmental factors. This will also require multiple sampling during a minimum of one-year following each placement of sand. r~T, While this may seem excessive, it will provide the scientific information necessary to I] effectively evaluate whether the biota on the rocky areas is being impacted. A program that incorporates sampling multiple times during a year will provide the basis for understanding the effect of natural seasonal changes in sand movement and biological populations. Sampling areas outside of the boundaries where added sand is expected to move will provide additional information on local environmental patterns or episodic events, without which monitoring results could be misconstrued. Thus, a monitoring program that incorporates sampling throughout the year and sampling areas away from the location(s) will lead to proper evaluation of the impact of the sand replenishment. A proper monitoring program will evaluate the impact of sand PI placement on the biological resources living on the rocky reefs considered at risk, reduce the ^ possibility that unwarranted mitigation would be required, and assess the accuracy of the sand movement model, thus providing important information necessary for future beach replenishment. 7. LITERATURE CITED (NMFS), N. M. F. S. (1991). Habitat Protection Policy, Southwest Region. Long Beach, CA, National Marine Fisheries Service (NMFS): 1. Abbott, I. A. and G. J. Hollenberg (1976). Marine Algae of California. Stanford, California, Stanford University Press. Dawson, E. Y. and M. S. Foster, Eds. (1982). Seashore Plants of California. California Natural History Guides. Berkeley, University of California Press. Dethier, M. N. (1984). "Disturbance and recovery in intertidal pools: maintenance of mosaic patterns." Ecological Monographs 54:99-118. Stewart, J. G. (1989). "Maintenance of a balanced, shifting boundary between the seagrass Phyllospadix and algal turf." Aquatic Botany 33: 223-241. Coastal Environments 8 Technical Report CE Reference No. 00-07 Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad I Terrados, J. and S. Williams (1997). "Leaf versus root nitrogen uptake by the surfgrass Phyllospadix torreyi." Marine Ecology Progress Series (MEPS) 149: 261-211'. Turner, T. (1985). "Stability of rocky intertidal surfgrass beds: persistence, preemption, and recovery." Ecology 66: 83-92. D Coastal Environments 9 Technical Report CE Reference No. 00-07 D D Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad APPENDIX A Photographs of the North Carlsbad Rocky Intertidal Resources Coastal Environments A-l Technical Report CE Reference No. 00-07 Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of Carlsbad Photograph 1. View of the beach extending north from a location below the Carlsbad parking lot located between Oak and Pine streets, 1/21/2000 (above). Note the lack of rocky intertidal reefs. Photograph 2. View of the beach extending south from a location below the Carlsbad parking lot located between Oak and Pine streets, 1/21/2000 (above). Rocky intertidal reefs are visible at the water's edge in the middle of the photograph. Coastal Environments CE Reference No. 00-07 A-1 Technical Report Observations on the Status of Biological and Physical intertidal Resources along the Coastline of Carlsbad Photograph 3a. View of the rocky intertidal reef located slightly south of the northernmost stairway to the beach walkway, 1/20/2000 (above). Note that the reef is small and that there is a sandbar offshore of the rocks. Photograph 3b. View of one of the larger rocks in the rocky intertidal reef located slightly south of the northernmost stairway to the beach walkway, 1/20/2000 (above). Note the lack of biological cover. Coastal Environments CE Reference No. 00-07 A-2 Technical Report Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of Carlsbad j Photograph 4a. View of the rocky intertida! reef located below and slightly south of Beachwalk Access Stairway 2 (numbered from the north) looking south, 1/21/2000 (above). Note the low relief of this rocky intertidal reef. Photograph 4b. Part of one of the rocks in the rocky intertidal reef located below and slightly south of Beachwalk Access Stairway 2, 1/21/2000 (above). This rock has numerous young mussels on it (the dark spots) as well as crustose coralline algae (pink) and sand. Coastal Environments CE Reference No. 00-07 A-3 Technical Report Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of Carlsbad Photograph 5a. View of the rocky intertidal reef located below and slightly south of Beachwalk Access Stairway 3 (numbered from the north) looking south, 1/21/2000 (above). Note the generally low relief of this rocky intertidal reef. A few rocks were as much as 1.5 feet above the sand although most were less than 1 foot. Also note the presence of a sand bar offshore of the reef. ; : Photograph 5b. Part of one of the rocks in the rocky intertidal reef located below and slightly south of Beachwalk Access Stairway 3, 1/21/2000 (above). This rock is covered by erect coralline algae (the pink areas), a small brown alga Zonaria farlowii (brown area), and sand. Coastal Environments CE Reference No. 00-07 A-4 Technical Report Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of Carlsbad Photograph 6a. View of algae on one of the scattered rocks comprising the intertidat reef below Beachwalk Access Stairway 4 (numbered from the north), 1/21/2000 (above). Erect coralline algae (Corallina spp.) is pink and Zonaria farlowii is brown. Note the presence of sand intermixed with the algae. Photograph 6b. Surfgrass on the rocky intertidal reef located below Beachwalk Access Stairway 4, 1/21/2000 (above). The surfgrass is on low relief rocks and has a considerable amount of sand on the rocks and around the bases of the surfgrass plants. Coastal Environments CE Reference No. 00-07 A-5 Technical Report Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of Carlsbad Photograph 7a. View of part of the submerged rocky intertidal reef located below Beachwalk Access Stairway 5 (numbered from the north), 1/21/2000 (above). Note the low relief of this rocky intertidal reef. Note the presence of sand intermixed with the rocks which supported erect coralline algae (pink areas). Photograph 7b. Surfgrass on the rocky intertidal reef located below Beachwalk Access Stairway 4 (numbered from the north), 1/21/2000 (above). The surfgrass is on low relief rocks and has a considerable amount of sand on the rocks and around the bases of the surfgrass plants. Coastal Environments CE Reference No. 00-07 A-6 Technical Report Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of Carlsbad Photograph 8a. View of one of the higher rocks in the rocky intertidal reef located below the Tamarack parking lot, 1/21/2000 (above). Note the low relief of this rock, the presence of erect coralline algae (pink areas) and sand on the rock. Photograph 8b. Rocky intertidal reef located below Tamarack parking lot, 1/21/2000 (right). In the foreground is a rock with erect coralline algae and further offshore is part of an extensive surfgrass bed. Coastal Environments CE Reference No. 00-07 A-7 Technical Report Observations on the Status of Biological and Physical Intertidal Resources along the Coastline of North Carlsbad APPENDIX B Surveys Coastal Environments B-l Technical Report CE Reference No. 00-07 ooo CN oo COTO_l £"55 COc 3CO O j*:oro CO01cu ooo-co ooo LO CD ooo-f-.in CO §oin oooCOCDro oooCO ooo oooa> oooCN cooO) CD_J CD W CD 0rsCDi+—o 0) o IO CDE CDCD ooo— COCDCD OOO SCD LOCD OOO —h- ooo-ID OOOin ooo CO ooo oooen <D 03JC OO OCD CM 22 Q. oi ICM £. en o^- *: Q c> CCDO)0)1 1 CD i 1 ! 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