Biology subjects

Prins, H. H. T.

Publications and source records attributed to Prins, H. H. T..

6 recordsLinked to original sources

bioRxiv2024

Interactions between weather, ungulates and geese create opportunities for wood-pasture cycles

Managing nature reserves to achieve coexistence of ungulate species and vegetation heterogeneity is challenging in small reserves. A central question is whether spatial heterogeneity is maintained or restored through occasional natural disturbances. This is the premise of the wood-pasture hypothesis, which asserts that natural disturbances, such as winter severity, are sufficiently significant to sustain the long-term coexistence of ungulate species and provide opportunities for the establishment of shrubs and trees, thereby enhancing vegetation heterogeneity. Testing the wood-pasture hypothesis under field conditions necessitates long-term time series of both vegetation and herbivore dynamics. Therefore, we employed a modeling approach to test this hypothesis. The study area was the Oostvaardersplassen, a nature reserve in the Netherlands characterized by rich and productive clay soil. This area hosts an assemblage of Heck cattle, Konik horses, and red deer. Additionally, large numbers of geese frequent this reserve, competing for the same food resources. The Oostvaardersplassen is one of the few areas in Europe where neither the populations of coexisting herbivore species nor the vegetation have been managed and its development was monitored for several decades. This provides unique insights into natural herbivore-vegetation interactions that can be applied to the management of other nature reserves. The results indicate that weather variability and the presence of both geese and large ungulates are essential factors in creating a heterogeneous landscape. The general pattern is that weather variability induces fluctuations in ungulate numbers, and geese reduce the numbers of ungulates. Coexistence of the three ungulate species remains possible regardless of weather variability and the presence of geese. However, the presence of the largest ungulate, cattle, is threatened when weather is highly variable and geese numbers are high. The vegetation is likely evolving towards a predominantly open landscape with occasional opportunities for the establishment of spiny shrub species. Nature reserves managed with an assemblage of ungulate species, which numbers are controlled by food supply, winter severity and competition, should thus focus on the substantial presence of a few species ("biomassality," e.g., for migratory birds) rather than achieving the highest species diversity in a small area ("biodiversity").

ecology↗

bioRxiv2024

Protected area establishment in Southern and Eastern Africa: Consequences for management today

To understand the complexities of managing protected areas, it is important to understand the causes for their established. We summarized the motives for establishing protected areas in Southern and Eastern Africa, and the possible consequences for management of these areas today. We scrutinised documents for 48 randomly selected protected areas and investigated, (1) when and why each of the protected areas was established? (2) what the management implications were of the reasons for incorporation for these areas? and (3) how/if the original management still impacts conservation in these areas today? First, we learnt that the establishment of protected areas occurred in three periods, namely, Period 1 when area protection was started to protect wild animals from decimation; Period 2 during which areas considered marginal for agriculture, prone to disease or sickness and considered uninhabitable for humans were set aside; and Period 3 when areas were proclaimed protected because of ecological or cultural importance. Second, we showed that the establishment of protected areas has ramifications for management of these areas today, which for Period 1 were remote logistics and tourism, anti-poaching difficulties, large size logistics and human wildlife conflict. Period 2 has consequences for community-land issues and intensive management, with Period 3 having intensive management to meet the objectives of these parks. Our insights have consequences for management of protected areas today, with Period 1 protected areas generally being managed on a laissez-faire approach and Period 2 and 3 protected areas being managed on a more intensive management basis.

ecology↗

bioRxiv2024

Provisioning polyethylene glycol (PEG) to large herbivores in nutrient poor savannas can break food limitation

Reproduction and survival of herbivores in nutrient poor savannas is low due to low nutrient and energy availability, partly caused by high levels of tannins. Polyethylene glycol (PEG) increases the availability of proteins for herbivores by binding tannins. The effect of PEG on the diet of free-roaming herbivores has not been tested. Our hypothesis was deploying lick blocks with the addition of PEG in a nutrient poor savanna, will result in a broadening of the diet of free-roaming herbivores with higher percentages of browse species and higher utilisation per browse species, with higher tannin levels. We further hypothesised that the mineral content in the faeces, once exposed to PEG would increase. We collected faecal samples of five herbivore species with various feeding methods (grazers, browsers or mixed feeders). The study used a Before-After-Control-Impact (BACI) design. The results show that the addition of PEG promotes a change in the browse dietary choices of four of the five herbivore species, and are expressed as a broader choice of diet, coupled with higher numbers of browse species with low edibility and higher tannin levels. The addition of PEG had no noteworthy effect on the concentration of minerals found in the faeces.

ecology↗

bioRxiv2024

Nutrient addition on grazing lawns and selection by free-roaming mammalian herbivores in a nutrient poor savanna

Grazing lawns are important food sources in nutrient poor savannas for free-roaming mammalian herbivores. It has been hypothesized that increased grazing pressure by mammalian herbivores can create and maintain patches of lawn grass. We tested whether the application of specific nutrients, nitrogen (N), phosphorus (P) or in combination with calcitic and dolomitic lime (Ca), in a nutrient poor African savanna, would make the grass sward more nutrient rich, which would attract mammalian herbivores to graze more frequently. We investigated the grazing patterns of six species of mammalian herbivores, namely, blue wildebeest (Connochaetes taurinus), Burchells zebra (Equus quagga burchellii), common eland (Taurotragus oryx), impala (Aepyceros melampus), square-lipped rhinoceros (Ceratotherium simum) and warthog (Phacochoerus africanus). We show that the addition of N attracts and increases the grazing pressure for three of the herbivore species, namely, blue wildebeest, Burchells zebra and impala. Our findings suggest that these often abundantly present mammalian herbivores with intermediate body mass, attracted to grazing lawns by the addition of N, can maintain grazing lawns. Conservation implicationsArtificial fertilization with nitrogen attracts large free-roaming herbivore species to localized grazing lawns, stimulating the creation and expansion of high nutrient quality lawn grasses in nutrient poor savannas. This results in a nutrient high food source which would normally not be available in nutrient poor savannas.

ecology↗

bioRxiv2024

Effects of mineral addition on the establishment of grazing lawns in a nutrient poor savanna

Nutrient poor savannas are often characterized by inedible or rarely palatable grasses, which generally provide poor nutrition for mammalian grazers. So-called grazing lawns, with short, stoloniferous edible grasses, could provide high-quality food for grazers, but these lawn grasses are rare in nutrient poor savannas. We tested whether we could use mineral addition to establish grazing lawns in a nutrient poor African savanna, in order to achieve a switch from tall, nutritionally poor to short, highly nutritional grass species. The key finding is that phosphorus and lime, nitrogen and nitrogen and lime supplementation resulted in shift from tall to short grasses within three years, with a higher overall nutrient concentration in the grass leaf, than without supplementation. When grazed, the cover of lawn grasses was higher compared to the other grasses when not grazed, demonstrating the role of grazers in maintaining and expanding lawn grass patches. We conclude that local fertilisation in nutrient poor savannas is a viable method of increasing mineral levels in the soil and grass leaf. We also concluded that grazing results in an increase in lawn grass cover and a combination of fertilisation and grazing can improve forage quality to ensure higher nutrient availability to herbivores.

ecology↗

bioRxiv2021

Habitat loss exacerbates pathogen spread: An Agent-based model of avian influenza infection in migratory waterfowl

Habitat availability determines the distribution of migratory waterfowl along their flyway, which further influences the transmission and spatial spread of avian influenza viruses (AIVs). The extensive habitat loss in the East Asian-Australasian Flyway (EAAF) may have potentially altered the virus transmission and spread, but those consequences are rarely studied. We constructed 6 fall migration networks that differed in their level of habitat loss, wherein an increase in habitat loss resulted in smaller networks with fewer sites. The networks were integrated with an agent-based model and a susceptible-infected-recovered model to simulate waterfowl migration and AIV transmission. We found that extensive habitat loss in the EAAF can 1) relocate the outbreaks northwards responding to the distribution changes of wintering waterfowl geese, 2) increase the outbreak risk in remaining sites due to larger bird congregations, and 3) facilitate AIV transmission among wintering geese. Our modelling output suggested that there was a certain system resilience of migration network to confront the site removal. In addition, the outputs were in line with the predictions from the concept of "migratory escape", affecting the pattern of infection prevalence in the waterfowl population. Our modelling shed light on the potential consequences of habitat loss in transmitting and spreading AIV at the flyway scale, and suggested the driving mechanisms behind these effects, advocating the importance of nature conservation in changing spatial and temporal patterns of AIV outbreak. Author summaryWhat are the possible consequences of extensive habitat loss on the transmission and spread of avian influenza viruses (AIVs)? We used a logistic regression model to select the suitable habitats of Greater white-fronted goose in the East Asian-Australasian Flyway and treated these habitats as sites to construct 6 fall migration networks that differed in their level of habitat loss (i.e., site removal). We then simulate geese migration in these networks, and explore the impacts of habitat loss on habitat connectivity and AIV transmission. We found the extensive habitat loss can cause relocation of the outbreaks and increase the outbreak risk and AIV transmission. Our modelling outputs suggested a certain network resilience to confront the site loss, and a "migratory escape" to change the spatial and temporal pattern of infection prevalence in the population. Overall, our study showed that land use changes and habitat loss can affect disease distribution and prevalence, suggested the importance of habitat conservation in changing the spatial and temporal pattern of AIVs transmission and spread.

ecology↗