Nile crocodiles threatened by alien weed

Nile crocodiles (Crocodylus niloticus) have no natural enemies. These efficient predators grow to a length of six meters and eat everything from fish to antelopes in wetlands across sub-Saharan Africa as they have for millennia. But recent findings in South Africa by Earthwatch Institute-supported researchers suggest that these ancient reptiles may have met their match. Nile crocodiles could face local extinction due to a perennial shrub.

The alien plant, known as locally as trifid weed (Chromolaena odorata), has invaded critical shoreline nesting habitat for crocodiles at Greater St. Lucia Wetland Park, a World Heritage Site in northern Kwazulu-Natal and the largest estuarine system in Africa. The fibrous roots of the weed cause some nesting crocodiles to abandon their nest sites, while shade from the plant alters the temperature of other nests, making them non-viable or resulting in all female hatchlings.

"This problem is definitely not limited to St. Lucia," said Dr. Alison Leslie, Department of Conservation Ecology at the University of Stellenbosch and chair of the Herpetological Association of Africa. "If ignored it will significantly affect crocodile populations in South Africa." Dr. Leslie and Dr. James Spotila of Drexel University reported their results, which were supported by volunteers on Earthwatch's Nile Crocodile project, in a recent issue of Biological Conservation (98 (2001), pp. 347-355).

As in several other reptiles, the sex of crocodiles is determined by the temperature of the nest while they are still in the egg, so that the sex ratio of hatchlings can be skewed by nest sites that are too warm or too cold. Female crocodiles at St. Lucia and elsewhere tend to return to the same nesting site year after year, usually open sandy areas close to the water. But when these nest sites are shaded by the invasive trifid weed, the hatchlings are like to be entirely female, threatening the viability of the population.

"We found a three-to-one

Contact: Dr. Alison Leslie
Earthwatch Institute

Page: 1 2

Related biology news :

1. Danger spots identified for threatened grizzly bear
2. 51 globally threatened species get new lease on life in the Caucasus
3. Bighorn sheep threatened by climate change
4. California pistachio industry threatened by potentially devastating disease
5. Tourism to Earths most threatened areas surges by over 100 percent in last decade
6. More than 700 threatened species remain completely unprotected, new study shows
7. Lake ecosystem critical to East African food supply is threatened by climate change
8. Plant diversity threatened by climate change and buildup of greenhouse gas, study reveals
9. Rare Asian dolphin threatened by human activities
10. Walleye fishery threatened; Puerto Rico aquaculture, calling ALVIN on ocean bottom
11. One in every three primates now threatened with extinction

Post Your Comments:

(Date:5/1/2020)... ... April 30, 2020 , ... ... Siemens Healthineers and several healthcare VC firms announces an official launch of CareDoctors.com. ... is to enhance patient care experience by offering live video consultations with board ...
(Date:5/1/2020)... SEATTLE (PRWEB) , ... April 30, 2020 , ... ... for emerging infectious diseases, announced today that it had been awarded a contract ... of the Assistant Secretary for Preparedness and Response at the U.S. Department of ...
(Date:4/30/2020)... ... April 28, 2020 , ... Pebble Labs USA ... challenges in agriculture and aquaculture with the mission of improving global food security, announced ... F&A Next ' Next Heroes in Food- and Ag-Tech ' virtual event, a global ...
Breaking Biology News(10 mins):
(Date:4/26/2020)... ... April 23, 2020 , ... ... today, an online store providing applications and services for use on Microsoft Azure. ... business needs to sign up online for a built-for-purpose customer engagement capability to ...
(Date:4/22/2020)... ... April 20, 2020 , ... ... MA, announced today that Omixon’s founder and chairman Dr. Attila Berces returns as ... product Holotype HLA since 2014 before stepping into the CEO role in 2017. ...
(Date:4/22/2020)... ... April 21, 2020 , ... Ripple Science ... Many clinical trial teams are working remotely and have paused patient visits, forcing ... researchers continue their research during this uncertain time by giving research teams free ...
(Date:4/7/2020)... (PRWEB) , ... April 06, 2020 , ... Gateway ... future children, reached 200,000 SneakPeek Early Gender DNA Tests sold in March, ... was launched as an ecommerce product, where a mom could order her kit ...
Breaking Biology Technology:
Cached News: