How can ecosystem engineer plants boost productivity in east Mediterranean drylands  

作　　者：Elena Constantinou Dimitrios Sarris Magda Psichoudaki Javier Cabello Ioannis N.Vogiatzakis 

机构地区：[1]Faculty of Pure&Applied Sciences,Open University of Cyprus,2252 Nicosia,Cyprus [2]KES Research Centre,1055 Nicosia,Cyprus [3]KES College,1055 Nicosia,Cyprus [4]Nireas-International Water Research Center,University of Cyprus,P.O.Box 20537,1678 Nicosia,Cyprus [5]Andalusian Center for the Assessment and Monitoring of Global Change,University of Almería,04120 Almería,Spain [6]Department of Biology and Geology,University of Almería,04120 Almería,Spain.

出　　处：《Ecological Processes》2023年第1期425-437,共13页生态过程（英文）

摘　　要：Background Water availability is the key limiting factor for plant productivity in drylands covering ca.40%of Earth’s land surface.For such ecosystems to retain productivity and biodiversity under climatic change,it would be valu-able to identify/promote keystone plant species that(i)have developed strategies to more efficiently utilize moisture resources not easily accessible and(ii)improve moisture conditions for neighboring plants.The very deep-rooted Ziziphus lotus,considered an ecosystem engineer,is one such example.However,it is not known which biotic traits:(a)canopy interception of moisture/rainfall,(b)hydraulic redistribution of deep ground moisture by roots,or non-biotic factors:(c)soil’s volume,and(d)organic matter content,Z.lotus activates/modulates to play such a role.We,thus,selected dryland ecosystems where the plant dominates and measured for potential effects on the less deep-rooted Thymbra capitata.For assessing impacts on ecosystem productivity,we measured the spatial aggregation of ca.3600 T.capitata plants.As a proxy for soil moisture availability and its spatial variability,we conducted a 7-year-long study using thymes’nighttime rehydration.Sampling extended up to 15 m away from Z.lotus.Results The density of T.capitata plants growing up to 5 m around Z.lotus vs.thymes growing 10-15 m away was found significantly increased(2.5-4.5 times),while their stem/leaf moisture was ca.10%higher at predawn compared to nightfall during the dry season.This suggests that ecosystem productivity is driven by a greater soil moisture avail-ability around Z.lotus permitting more thyme daytime transpiration,in contrast to thymes growing further away.The phenomenon appeared only under dry topsoil(during the dry season;becoming stronger during dry years).Morning dew/rainfall interception from the canopy or soil depth/organic matter did not show significant effects,leaving only the hydraulic lift properties of Z.lotus as the most likely driver for soil moisture availability.Conclusions The deep-rooting prope

关 键 词：Plant–plant interaction DESERTIFICATION Mediterranean DRYLAND Moisture content Deep root Ziziphus lotus Stress-gradient 

分 类 号：Q948[生物学—植物学]