Spatial patterns of invertebrate settlement in giant kelp forests
نویسندگان
چکیده
Settlement of kelp-associated organisms may vary as they are delivered to (and through) giant kelp (Macrocystis pyrifera) forests, with implications for local population dynamics and community structure. Previous work suggests that settlement of invertebrates with long pelagic durations would be reduced as they move from an offshore environment toward the interior of kelp forests due to dampened current flow and reduced larval delivery. We evaluated spatial variation in settlement across giant kelp forests in an extensive field study conducted over 2 yr. We collected and sorted >36000 settling organisms and had sufficient data to explore patterns in detail for 8 taxa. Orthogastropods (snails) were the most common invertebrates and exhibited a pattern of declining settlement from the outer (seaward) to inshore edge of kelp forests. Inverse patterns were observed for Crepidula spp. and carideans, and other abundant taxa (non-sessile polychaetes and pectinids) showed spatial structure that differed regionally and between years. Other taxa failed to exhibit significant spatial variation in settlement. In general, settlement was lower near the sea floor than in the upper water column, and similar across locations for most groups. For some taxa, spatial variation was more apparent when the magnitude of settlement was relatively low, which may suggest that kelp forests become ‘saturated’ with larvae during pulses of high settlement. Our results are in contrast to previous predictions, as we observed high settlement in the interior for several species with long pelagic durations. For taxa that settled evenly across kelp-forested reefs, differential distributions of adults may be attributed to post-settlement processes. The patterns we observed here warrant additional study to address potential mechanisms for differential settlement.
منابع مشابه
Synchrony in dynamics of giant kelp forests is driven by both local recruitment and regional environmental controls.
Populations of many species display spatially synchronous fluctuations in abundance. Synchrony is most commonly attributed to three processes: factors that influence recruitment (e.g., dispersal, early survival), large-scale environmental variability, and spatially autocorrelated trophic interactions. However it is often difficult to link population synchrony to a specific dominant process, par...
متن کاملWave disturbance overwhelms top-down and bottom-up control of primary production in California kelp forests.
We took advantage of regional differences in environmental forcing and consumer abundance to examine the relative importance of nutrient availability (bottom-up), grazing pressure (top-down), and storm waves (disturbance) in determining the standing biomass and net primary production (NPP) of the giant kelp Macrocystis pyrifera in central and southern California. Using a nine-year data set coll...
متن کاملScale-dependent changes in the importance of larval supply and habitat to abundance of a reef fish.
While there is great interest in the degree to which local interactions "scale-up" to predict regional patterns of abundance, few studies in marine systems have simultaneously examined patterns of abundance at both the large scale (tens of kilometers) typical of larval movement and the small scale (meters) typical of post-settlement interactions. We addressed this gap by monitoring larval suppl...
متن کاملCatastrophe, recovery and range limitation in NE Pacific kelp forests: a large-scale perspective
The 1997–98 El Niño was one of the strongest on record and resulted in widespread losses of the giant kelp Macrocystis pyrifera (Agardh) along the west coast of North America. Drawing on a rich history of studies that have shown abnormally large waves and warm nutrient-poor water associated with El Niños to negatively impact giant kelp populations at some locations in southern and Baja Californ...
متن کامل