Ten-year dynamics of vegetation in a Mediterranean temporary pool in western Morocco

Abstract

The aim of this work was to test the hypotheses that the species composition of the vegetation of one pool in Morocco change continuously along with rainfall fluctuations, that among the vegetation can be recognized Pool species and Opportunistic species with distinct dynamics in time.We expected the Pool species to show lower interannual variation than the Opportunistic species. This hypothesis was tested in a 10-year study of the species composition of the vegetation along two permanent transects. The results showed high cumulative species richness (95 species) with large differences between years and a predominance of annual species (77). The proportion of Pool species during these 10 years was low (39%) when compared to opportunists (61%). In dry years the Opportunistic species were dominant and declined during wet years. The number of Pool species was correlated with the amount of rainfall. A large number of these species revealed a preference for wet years. No negative interaction between annuals/perennials and pools/non-pools species was found, suggesting that competition was not a major process during the survey. The intensity of the drought and flood stress, related to climate fluctuations, seems to be the main factors controlling the species composition of the vegetation of this unstable habitat. However, beyond the inter-annual fluctuation of the species composition of the vegetation a directional change was noticed. This directional change could result from a recovery process of the vegetation during the first years of the study after a severe flood which extirpated most of the Opportunistic species of the pool. In the last years this directional change of the species composition of the vegetation is less clear and random recruitment of the Opportunistic species from the surrounding forested habitats could contribute to explain inter-annual changes. The data collected over Electronic supplementary material The online version of this article (

Pond conservation: from science to practice

“…Fahd et al (2009) present in this volume a four-decade record of the Copepods and Branchiopods associated with 50 temporary ponds in the Doñana National Park (SW Spain) and underline the usefulness of such long-term monitoring. Shorter time span can also already bring useful results, as demonstrated here by a 10-years continuous monitoring in a Mediterranean temporary pool facing fluctuating hydrology (Rhazi et al, 2009a).…”

“…The same evidence came also from studies of aquatic plants from these Mediterranean temporary ponds: hydrology appears to be the primordial factor that structures and selects the species of a community (Sahib et al, 2009;Rhazi et al, 2009a); the hydrology modifies any disturbance effects and influences competition intensity through its impact on primary production. The expected reduction of humid years and of rainfall globally may lead to a decrease in the probability of survival of populations of characteristic pool species (Rhazi et al, 2009a). Such data will be particularly useful in the future, because we expect drastic changes in hydroperiod length.…”

Distribution review, habitat suitability and conservation of the endangered and endemic Moroccan spadefoot toad (Pelobates varaldii)

“…Despite this, very few records of P. varaldii from this region exist. The cork oak forest surrounding Ben Slimane harbours substantial amounts of original habitat and over 600 temporary ponds are present in this region covering a total surface area of 1994 ha (RHAZI et al, 2009). The multiple surveys into this area surprisingly did not produce any records of P. varaldii presence despite extensive dip netting of many temporary ponds.…”

Biodiversity and Conservation of Temporary Ponds — Assessment of the Conservation Status of “Veiga de Ponteliñares”, NW Spain (Natura 2000 Network), Using Freshwater Invertebrates

“…The expected reduction of humid years and of rainfall globally may lead to a decrease in the probability of survival of populations of characteristic pond species [31]. Thus, changes in the hydrology will be a key factor to investigate.…”