Summary Woody plants store large quantities of carbon (C) and nutrients. As plants senesce and decay, these stores transfer to the soil or other organisms or are released to the atmosphere. Exogenous factors such as topographic position and microclimatic and edaphic conditions tied to locations affect decay rates; however, we know less about how exogenous relative to endogenous factors such as morphological, anatomical and chemical construction tied to plant species affect these rates, especially across different tissue types. We monitored stem, fine branch and leaf decay over 1 year in ‘rot plots’ distributed across four watersheds in ridge top and valley bottom habitats in a temperate deciduous oak‐hickory forest at Tyson Research Center, MO, USA, in the Ozark Highlands for 21 species of woody plants that vary in their constructions. We found poor coordination across tissues in construction and decay, which likely reflects how functional constraints on living tissues influence recalcitrance to decay. Additionally, for all three tissues, species membership and construction were better predictors of decay than was location. Of the construction traits, chemical composition including total fibre, lignin, cellulose, hemicellulose and concentrations of multiple microelements were the best predictors of decay, although the strength of these relationships differed among tissues. Synthesis. We have long known that rates of biogeochemical cycling are influenced by exogenous factors, such as climatic and edaphic factors. Here, we show across plant tissues that endogenous factors, including species identity and tissue construction, can have stronger controls on rates of decay within our study system than do exogenous factors. However, it is likely that the relative strengths of these different controls change through time and among tissues. We predict that anatomical and morphological controls may be more important at early stages and exogenous factors may be more important at later stages of decay.
For 30 years, regular aerial surveys in Zimbabwean protected areas were funded, designed and executed primarily to estimate elephant numbers. Other large herbivores were recorded, even though some species were not easily seen from the air in savannah woodlands. Population estimates for species other than elephant provided indices of abundance that could be used to determine temporal trends in population size. This study tests for significant trends in the abundance of large herbivores in Gonarezhou National Park, assuming that data from aerial sample surveys designed for elephant also provide accurate estimates of real trends in the populations of other herbivores. For each species, the exponential rate of population change was calculated using weighted regression, with the variance of this rate based on the sampling variances of the population estimates. Significant population trends were detected for eight species. Before the 1992 drought, elephant number was held approximately constant by frequent culls, but afterwards, it increased at a mean annual rate of 6.2% (confidence limits 4.0% and 8.6%). Elephants in cow herds increased at 7.3%, significantly faster than elephants in bull herds (−0.5%). Buffalo, eland, kudu, nyala, waterbuck, wildebeest and zebra all increased in number, after population declines during the drought.
Human–wildlife conflicts are common across Africa. In Mozambique, official records show that wildlife killed 265 people during 27 months (July 2006 to September 2008). Crocodile Crocodylus niloticus, lion Panthera leo, elephant Loxodonta africana and hippopotamus Hippopotamus amphibius caused most deaths but crocodiles were responsible for 66%. Crocodile attacks occurred across Mozambique but 53% of deaths occurred in districts bordering Lake Cabora Bassa and the Zambezi River. Hippopotamus attacks were also concentrated here. Lion attacks occurred mainly in northern Mozambique and, while people were attacked by elephants across the country, 67% of deaths occurred in northern Mozambique. Attacks by lions, elephants or hippopotamuses were relatively rare but additional data will probably show that attacks by these species are more widespread than the preliminary records suggest. Buffalo Syncerus caffer, hyaena Crocuta crocuta and leopard Panthera pardus were minor conflict species. Good land-use planning, a long-term solution to many conflicts, is particularly relevant in Mozambique, where the crocodile and hippopotamus populations of protected areas are often in rivers that border these areas, and cause conflicts outside them, and where people commonly live within protected areas. Poverty may prompt fishermen to risk crocodile attack by entering rivers or lakes. The high incidence of conflicts near Limpopo and South Africa’s Kruger National Parks (both within the Great Limpopo Transfrontier Conservation Area) highlights the problems created for people by facilitating the unrestricted movement of wildlife between protected areas across their land.
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