Improvement of Native Pasture Productivity through Introduction of Various Types of Palatable Species on Dry Lands in Timor

This research was aimed to evaluate the productivity of native pasture in Timor Island by introducing various palatable species.The study was carried out on native pasture in Tuatuka,Timor Island for seven months.The study was performed by using randomized block design(RBD)with eight treatments(S0:no introduction,S1:Cynodon dactilon,S2:Dicanthium aristatum,S3:C.plectotachyus,S4:Brachiaria decumbens,S5:Desmanthus virgatus,S6:Macroptilium atropurpureum,S7:Clitoria ternatea)with four replications.Procedures on this study include trial plots preparation,tillers preparation for each species,introduction of species in trial plots,maintenance and observation of the productivity.Variables observed were forage production(fresh and dry matter(DM)in ton/ha),nutrient content(%)and stock capacity(animal unit(AU)/ha).Data were analyzed for variance based on RBD and followed by Duncan’s test.Analysis of variance showed that introduction of species had a very significant effect(p<0.01)on all observed variables.The introduction of M.atropurpureum produced the highest fresh forage(2.1 t/ha)and DM production(0.69 t/ha).M.atropurpureum also had the highest DM content(43.61%),nitrogen free extract(52.52%)and stock capacity(1.06 AU/ha).The highest crude protein and crude fiber content were found in D.virgatus(4.31%and 36.62%).The highest extract ether was observed in D.aristatum(1.48%).No introduction had the lowest productivity,but demonstrated the highest ash content.The introduction of palatable species increased the productivity of native pasture in Timor and M.atropupureum was the best introduced species.

Fine-scale analysis of heavily invaded Italian freshwater fish assemblages

Inland waters are highly vulnerable to the introduction and spread of non-native species,due to heavy human use of aquatic ecosystems and the natural linkages among streams and lakes.This is particularly noticeable in freshwater fish communities.To better evaluate how these communities are affected by non-native species intro­ductions,we conducted a fine-scale analysis of the changes in Italian freshwater fish assemblages after species introduction.For this analysis,we collected information on fish species present in 44 basins.The present Ital­ian freshwater fish fauna is composed of 48 native and 41 established introduced species,while a further 15 in­troduced species have been reported but are not yet considered naturalized.The changes in the fish assemblages mostly took place in the past 2 centuries and have increased recently,with nearly 60%of the species introduced in the past 3 decades.The number of species introduced per basin ranged from 0 to 35(mean 10.85±7.77 spe­cies/basin),and in 10 basins the number of species introduced is now equal to or even higher than the number of native species.In the past,introduced species mainly originated from America,but over the past three de­cades,an increase of introductions from other parts of Europe and Asia has been recorded.Our results show that basins already rich in native species tend to become even richer as a consequence of the establishment of intro­duced species.This confirms the trend toward a biotic homogenization of ecosystems even at a local scale,due to an increase in the human-mediated spread of generalist species.

An intercontinental comparison of insect seed predation between introduced and native oaks

Novel interactions between introduced oaks and their natural enemies across different continents provide an opportunity to test the enemy release hypothesis(ERH)at local and global scales.Based on the ERH,we assessed the impacts of native seed-feeding insects on introduced and native oaks within and among continents.We combined a common-garden experiment in China and biogeographic literature surveys to measure seed predation by insects and the proportion of acorn embryos surviving after insect infestation among 4 oak species with different geographical origins:Quercus mongolica origin from China,Q.robur and Q.petraea from Europe,and Q.rubra from North America.Mostly supporting the ERH,oaks in introduced continents escaped seed predation compared to those in native continents and compared to other native oaks in introduced continents.Common-garden comparisons showed that total acorn infestation rate of introduced Q.rubra(section Lobatae)was considerably lower than that of native oaks(section Quercus)in China and Europe,likely because of the differences in seed traits associated with different oak sections.Literature surveys showed that seed predation of introduced oaks was lower in the introduced continent than in the native continent.Embryo survival was higher in introduced Q.rubra than native oaks in China and Poland.However,insect seed predation of recently introduced Q.rubra in China was similar to that in Europe,which is not consistent with the ERH.Our results suggest that reduced acorn attack by native insects and higher embryo survival after acorn damage could increase the establishment success or invasion risk of introduced oaks in non-native continents.