The Ecohistory of Tanzania’s Northern Rift Valley – Can One Establish an Objective Baseline as an Endpoint for Ecosystem Restoration?

Prins, Herbert H. T.; Jong, Joost F. de

doi:10.1007/978-3-030-93604-4_7

Cited by 10 publications

(24 citation statements)

References 104 publications

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“…It enables the assessment of the magnitude of changes, and determination of whether the current state of wildlife populations aligns with historical baselines or represents a concerning departure from them. Consequently, achieving the goal of restoring wildlife populations to historical baselines would require much more effective conservation actions than those currently employed (Prins & de Jong, 2022).…”

Section: Discussionmentioning

confidence: 99%

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Assessing protected area effectiveness in western Tanzania: Insights from repeated line transect surveys

Kiffner,

Giliba,

Fust

et al. 2023

Afr J Ecol

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In many parts of East Africa, wildlife populations have declined over the past decades. Given these trends, site‐based studies are needed to assess how protected areas with differing management strategies enable the effective conservation of wildlife populations. In Tanzania, game reserves are managed for tourist hunting, while national parks are managed for non‐consumptive wildlife‐based tourism. To assess the relative performance of these management strategies, we here focus on two areas: Rukwa Game Reserve (RGR) and Katavi National Park (KNP). Based on systematically designed line distance surveys in 2004 and 2021, we compared densities and group sizes of large mammal populations (African elephant, giraffe, buffalo, zebra, topi, and hartebeest) over time. Contrary to published ecosystem‐wide declines observed in numerous species which considered earlier baselines, we did not detect significant population declines between 2004 and 2021. While these new results showing apparent stable populations do not invalidate earlier studies on wildlife declines, they could indicate a stabilisation phase after declines. This highlights the importance of considering appropriate temporal baselines and historical contexts when assessing conservation effectiveness.

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Section: Discussionmentioning

confidence: 99%

“…Consequently, achieving the goal of restoring wildlife populations to historical baselines would require much more effective conservation actions than those currently employed (Prins & de Jong, 2022).…”

Section: Did Wildlife Populations Decline Between 2004 and 2021?mentioning

confidence: 99%

Assessing protected area effectiveness in western Tanzania: Insights from repeated line transect surveys

Kiffner,

Giliba,

Fust

et al. 2023

Afr J Ecol

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“…prior to the 1980s). Therefore, elucidating whether the populations of Manyara monkey and vervet monkey have declined, increased, or remained largely unaffected by the substantial changes that occurred in LMNP over recent decades (Prins and de Jong, 2022) cannot be established with certainty.…”

Section: Population Dynamicsmentioning

confidence: 99%

“…Water flow from catchment areas has markedly declined (Prins and de Jong, 2022), but floods occur more frequently, leading to silting of the lake (Janssens de Bisthoven et al, 2020). The once predominantly open savannah habitats have transitioned into woodlands with a dense understorey (Kiffner et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Population dynamics of the Manyara monkey (Cercopithecus mitismanyaraensis) and vervet monkey (Chlorocebus pygerythrus) in Lake Manyara National Park, Tanzania

Kiffner

Kioko

Butynski³

et al. 2022

Primate Biol.

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Abstract. Estimating population densities and their trends over time is essential for understanding primate ecology and for guiding conservation efforts. From 2011 through to 2019, we counted two guenon species during seasonal road transect surveys in Lake Manyara National Park: the Tanzania-endemic Manyara monkey Cercopithecus mitis manyaraensis (International Union for Conservation of Nature and Natural Resources, IUCN, Red List category of “endangered”) and the vervet monkey Chlorocebus pygerythrus (Red List category of “least concern”). To account for imperfect detectability, we analysed the data in a line distance sampling framework, fitted species-specific detection functions, and subsequently estimated seasonal densities. To test for seasonal differences and yearly trends in the species-specific density estimates, we fitted generalized additive models. Seasonal point density estimates fluctuated considerably during the 9 years (2011–2019) of our study, ranging from 3 to 29 individuals km−2 for Manyara monkeys and from 19 to 83 individuals km−2 for vervet monkeys. Densities of both taxa did not differ seasonally, and we did not detect marked directional population trends. Our study illustrates the utility and limitations of line distance sampling for long-term primate monitoring. Beyond informing primate ecology and management, our results highlight the conservation importance of Lake Manyara National Park for primate conservation.

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“…The Serengeti Ecosystem (~33,000 km 2 ) and the Tarangire Ecosystem (~25,000 km 2 ) are two of the most critical ecosystems in Tanzania for biodiversity conservation. Both ecosystems conserve biodiversity and large landscapes, and support two of Africa's few remaining long‐distance migrations of large mammals including the white‐bearded wildebeests ( Connochaetes taurinus ) and the plains zebras ( Equus quagga ) and along with their major predators including lions ( Panthera leo ) and leopards ( Panthera pardus ) (Bond et al, 2022 ; Estes, 2014 ; Guy et al, 1981 ; Hopcraft et al, 2013 ; Lamprey, 1964 ; Lohay et al, 2022 ; Morrison et al, 2016 ; Prins & de Jong, 2022 ; Sinclair, 2012 ). Each ecosystem also host two of the largest remaining populations of Masai giraffes (Figure 1b ), (Bolger et al, 2019 ; Lee & Bolger, 2017 ; Lee & Bond, 2022 ; Lee & Strauss, 2016 ; Strauss et al, 2015 ), with substantial contributions to vegetation dynamics, food webs, and community ecology.…”

Section: Introductionmentioning

confidence: 99%

Genetic evidence of population subdivision among Masai giraffes separated by the Gregory Rift Valley in Tanzania

Lohay

Lee

Wu-Cavener

et al. 2023

Ecology and Evolution

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The Masai giraffe has experienced a population decline from 70,000 to 35,000 in the past three decades and was declared an endangered subspecies by the IUCN in 2019. The remaining number of Masai giraffe are geographically separated by the steep cliffs of the Gregory Rift escarpments (GRE) in Tanzania and Kenya dividing them into two populations, one west and one east of the GRE. The cliffs of the GRE are formidable barriers to east–west dispersal and gene flow and the few remaining natural corridors through the GRE are occupied by human settlements. To assess the impact of the GRE on Masai giraffe gene flow, we examined whole genome sequences of nuclear and mitochondrial DNA (mtDNA) variation in populations located east (Tarangire ecosystem) and west (Serengeti ecosystem) of the GRE in northern Tanzania. Evidence from mtDNA variation, which measures female‐mediated gene flow, suggests that females have not migrated across the GRE between populations in the Serengeti and Tarangire ecosystems in the past ~289,000 years. The analysis of nuclear DNA variation compared to mtDNA DNA variation suggests that male‐mediated gene flow across the GRE has occurred more recently but stopped a few thousand years ago. Our findings show that Masai giraffes are split into two populations and fulfill the criteria for designation as distinct evolutionary significant units (ESUs), which we denote as western Masai giraffe and eastern Masai giraffe. While establishing giraffe dispersal corridors across the GRE is impractical, conservation efforts should be focused on maintaining connectivity among populations within each of these two populations. The importance of these efforts is heightened by our finding that the inbreeding coefficients are high in some of these Masai giraffe populations, which could result in inbreeding depression in the small and fragmented populations.

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The Ecohistory of Tanzania’s Northern Rift Valley – Can One Establish an Objective Baseline as an Endpoint for Ecosystem Restoration?

Cited by 10 publications

References 104 publications

Assessing protected area effectiveness in western Tanzania: Insights from repeated line transect surveys

Assessing protected area effectiveness in western Tanzania: Insights from repeated line transect surveys

Population dynamics of the Manyara monkey (Cercopithecus mitismanyaraensis) and vervet monkey (Chlorocebus pygerythrus) in Lake Manyara National Park, Tanzania

Genetic evidence of population subdivision among Masai giraffes separated by the Gregory Rift Valley in Tanzania

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