http://vital.seals.ac.za:8080/vital/access/manager/Index en-us 5 http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10438 Wed 12 May 2021 23:13:27 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10453 Wed 12 May 2021 22:30:17 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10630 70 percent). It was observed that browsing on trees resulted in a clear browse-line and browsing on propagules mainly by goats resulted in reduced seedling establishment in most of the estuaries except those in protected areas. Mangroves had re-established in estuaries where they had been previously lost but mouth closure due to drought and sea storms resulted in the mass die back of mangroves in the Kobonqaba Estuary. There was a total loss of 31.5 ha in mangrove area cover in the last 30 years and this was a total reduction of 10.5 ha (11 percent) for every decade. This is high considering that the present total mangrove area cover is only 240.6 ha for all the Transkei estuaries. In this study it was concluded that the anthropogenic impacts such as livestock browsing and trampling as well as harvesting in these estuaries contributed most to the mangrove degradation as these are continuous pressures occurring over long periods and are expected to increase in future with increasing human population. Natural changes such as sea storms occur less frequently but could result in large scale destruction over shorter periods. Examples of these are mouth closure that result in mangrove mass mortality as well as strong floods which destroy forest by scouring of the banks.]]> Wed 12 May 2021 21:00:01 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10689 50 years of impacts on the thicket shrub community and test their spatial and temporal extent near water. I confirm the vulnerability of thicket to transformation (particularly near water) as the accumulated influences of elephant reduce community composition and structure, and predict that these impacts will eventually bring about landscape-level degradation and a significant loss of biodiversity. Importantly, results show an uneven distribution of effects between elements of this community: from community composition and structure, to the structure of individual canopy species and ecological functioning. While these findings confound our interpretation of the extent of the impacts, it demonstrates the importance of explicitly recognizing biodiversity and heterogeneity for the conservation management of elephant. Finally, I test the consequences of the impacts for coexisting rhinoceros. While I show that this causes rhinoceros to change their foraging strategies in the presence of elephant at high densities, I also show that elephant may facilitate access to food for rhinoceros at reduced densities. These findings indicate the importance of elephant in driving the structure and composition of the thicket shrub community and the consequences of this for coexisting large herbivores. Thus, developing a predictive understanding of the spatial and temporal variations of elephant impacts between elements of biodiversity and the mechanisms driving these changes are key to their management. This implies that the effective conservation management of elephant can only be achieved through the careful, scientific design of monitoring programmes.]]> Wed 12 May 2021 20:53:58 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10472 Wed 12 May 2021 19:25:08 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10688 Wed 12 May 2021 17:58:04 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10663 Wed 12 May 2021 17:55:37 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10452 Wed 12 May 2021 17:31:05 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10709 Wed 12 May 2021 16:49:13 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10549 Wed 12 May 2021 16:30:14 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:9387 Wed 12 May 2021 16:14:35 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10708 Wed 12 May 2021 16:11:36 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10482 Wed 12 May 2021 16:04:46 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10489 Wed 12 May 2021 15:51:55 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:26423 Thu 13 May 2021 08:53:16 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10637 7 days) but could survive submergence of short duration (< 7 days) through continuous underwater photosynthesis, accumulation of osmolytes such as oxalic acid and carotenoid, and maintenance of relative water content and succulence within control levels. When considered together, results showed that the two upper intertidal species were sensitive to waterlogging and would not survive complete submergence, whereas the lower intertidal species could in addition to its natural range, thrive in conditions typical of the upper intertidal range, namely prolonged dry conditions and high sediment salinity. These results have important implications for the future management of salt marshes under predicted climate change conditions. In permanently open South African estuaries, a landward migration of salt marsh will be possible if coastal squeeze is limited and the rate of landward recruitment is on par with sea level rise. In this case salt marsh species would retain their current zonation while shifting inland. Increased sea storms and saltwater intrusion could lead to high salinity concentration in the sediment and significantly reduce growth of salt-sensitive plants. In estuaries that are temporarily open to the sea, reduced freshwater inflow will result in an increase in mouth closure, high water levels, prolonged submergence, and consequently die back of salt marsh vegetation. On the other hand increased abstraction and drought would result in low water levels and high sediment salinity which would decrease growth and survival of salt marsh. This research has provided new knowledge on the ecophysiology of salt marsh plants which can be used to predict the responses of plants to climate change.]]> Thu 13 May 2021 07:33:25 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10559 Thu 13 May 2021 07:18:21 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10449 Thu 13 May 2021 07:13:00 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10607 Thu 13 May 2021 06:16:18 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10404 Thu 13 May 2021 04:05:40 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10668 Thu 13 May 2021 03:57:49 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10619 Thu 13 May 2021 02:22:04 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10687 Thu 13 May 2021 01:55:52 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:26418 Thu 13 May 2021 01:48:43 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10669 Thu 13 May 2021 01:05:14 SAST ]]> http://vital.seals.ac.za:8080/vital/access/manager/Repository/vital:10483 Thu 13 May 2021 00:30:52 SAST ]]>