Short‐ and long‐term patterns of sponge diversity on a rocky tropical coast: evidence of large‐scale structuring factors

Abstract

The importance of a long-term ecological perspective is well documented, yet long-term data are not widely available. This paper represents the first quantitative description of sublittoral sponge assemblages over long temporal scales (6 years) along the coast of the East Pacific Ocean (Mazatlan Bay), with the goal of describing their levels of intra-and inter-annual variability, and their relationship to changing environmental conditions. It was possible to detect an apparent short-term pattern (intra-annual), with a highly diverse and stable structure, usually in the drought season, which was consistent most of the years. However, only a few species showed regular (predictable) seasonal cycles. The species per square meter (from 0.1 to 0.5), total species per sampling (14-21), and H' diversity using log e (1.4-2) also fluctuated greatly between years, suggesting that although a consistent short-term pattern was found most of the years, the inter-annual variability was also high. The univariate and multivariate results and regression models indicated that local winds played a key role in this shortterm pattern (intra-annual). During the rainy season, or during the transition between the drought and rainy season, the winds coming from the southwest (WSW) produced an increase in the net sediment movement, which was an important factor for diversity. The long-term fluctuations (annual pattern of diversity) also correlated positively with wind speed (88% of the variance observed) and with sediment deposition (69% of the variance observed). In addition, the results indicated the existence of large-scale structuring factors, as the annual pattern of diversity also was correlated positively with the Southern Oscillation (SOI) and Multivariate ENSO (MEI) indices (82% and 88% of the observed variance, for MEI and SOI, respectively). In conclusion, this study suggests that sponge assemblages in Mazatlán Bay are extremely dynamic, and changes in this community are associated with processes that occur over the short-and long-time scales (several months to several years). The significant positive relationship between wind speed and sediment deposition showed that the main factors controlling the diversity in these shallow rocky ecosystems are the winds and the swell. A high proportion of coarse sand also indicated a very high energy in the environment, which, combined with the effect of silting, abraded and removed sponges and other organisms. These features contribute to the instability of the community by producing dramatic fluctuations in species abundance and preventing competitive processes from producing a more stable community.

Sponge–rhodolith interactions in a subtropical estuarine system

“…52 ind m -2 ) and richness (max. 6.1 species m -2 ) of sponges were comparable with those reported in rocky habitats (17.5 ind m -2 and 4.3 species m -2 , Bell and Carballo 2008;Carballo et al 2008) and Sargassum beds (23.9 ind m -2 and 4.8 species m -2 , Á vila et al 2010) of the region.…”

Spongivory in the Wakatobi Marine National Park, Southeast Sulawesi, Indonesia

“…In the Ca rib be an, a long -term de cline (over 14 years) in abun dance and diver sity of a reef sponge com mu nity was linked to dis ease in Panama (Wulff 2006 b ) and increases in abun dance of X. muta over a 6 -yr pe riod were re lated to re cruit ment pulses in the Florida Keys (McMurray et al 2010). A study of a sub trop i cal rocky coast sponge assem blage in Mexico revealed short -term fl uctu a tions were cor re lated with sea sonal changes in lo cal wind pat terns and sed i ment de po sition, nested within large -scale an nual patterns re lated to the Southern Oscillation and Multivariate El Ni ñ o Southern Oscillation indi ces (Carballo et al 2008). Longer -term mon i tor ing of the sponge as sem blages at Hoga and Sampela are nec es sary in or der to de ter mine the cause of the ob served in crease in sponge abun dance and whether these increases are part of a long -term trend or shortterm sea sonal fl uc tu a tions.…”

Patterns of Sponge Abundance Across a Gradient of Habitat Quality in the Wakatobi Marine National Park, Indonesia

“…A 14 year study of sponges on a shallow reef in Panama revealed a steady disappearance of sponge species over the study period possibily due to sponge disease [35]. The results of a six year study in Mexico found short-term and long term fluctuactions in sponge densities as a result of seasonal changes in wind patterns and large-scale structuring factors such as the El Niño Southern Oscillation [36]. These contrasting results indicate that the factors controling sponge densities are likely to vary on different reef systems.…”